PATENTS   
Patents > Guidance, Tools, and Manuals >> Classification >>> Class Definition
    Class Numbers & Titles   | Class Numbers Only   | USPC Index   | International   | HELP  
You are viewing a Class definition.

 [Search a list of Patent Appplications for class 423]   CLASS 423,CHEMISTRY OF INORGANIC COMPOUNDS
Click here for a printable version of this file

SECTION I - CLASS DEFINITION

This is the generic class for:

1. Inorganic Compounds

2. Nonmetallic Elements

3. Processes . . . (a) Processes of producing or separating by a chemical reaction a product a product of 1. or 2. supra, (b) chemical reaction processes not elsewhere provided for, (c) processes of separating or purifying a gaseous mixture including a chemical reaction and (d) processes which are directed to extracting, leaching or dissolving a product or 1. or 2. supra from a mixture either, per se, or in combination with steps not otherwise provided for and for dissolving of such a product to make a water solution thereof.

AMPLIFICATION OF CLASS SUBJECT MATTER

This class provides for what is generally termed the field of inorganic chemistry. It includes inorganic compounds, nonmetallic elements and processes of producing the same involving a chemical reaction. The products are generally in a relatively pure state but may be a mixture with no other utility than as a source material for an inorganic compound or element. This includes metal compound products useful in metallurgical processes of obtaining free metals (see Subclass References to the Current Class, below).

A mixture of an inorganic compound or nonmetallic element with a preserving agent whose sole function is to prevent physical or chemical change of such compound or element is provided for in this class, unless the mixture is disclosed or claimed as having a function or utility provided for in the composition classification (see Subclass References to the Current Class, below). Also, processes of merely incorporating a preservative are included in this class.

The rules for determining class placement of the original reference (OR) for claimed chemical compositions are set forth in the class definition for compositions. See the (17) Note under LINES WITH OTHER CLASSES AND WITHIN THIS CLASS for additional information.

This class also provides for processes of separating or purifying a normally gaseous mixture by a chemical reaction, unless the resulting mixture has a disclosed utility provided for in the composition classification.

This class is also the residual class for all chemical reactions not provided for elsewhere, e.g., a reactive process where no specific product compound is disclosed.

For this class, the nonmetallic elements are: the halogens including astatine, the inert gases, hydrogen, boron, carbon, silicon, nitrogen, phosphorus, oxygen, sulfur, selenium and tellurium.

This class is also the class for extracting, leaching or dissolving processes not provided for elsewhere (see Subclass References to the Current Class, below).

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

(1) Note. An inorganic compound for this class must contain a nonmetallic element; intermetallic compounds, or union of metallic elements only are excluded and will be found in Class 420.
(2) Note. Subclasses which recite nitrogen or hydrogen in their titles do not include the ammonium radical (NH4+) within their definitions; the NH4+radical is considered to be, and is treated as, an entity or element, equivalent to Na, Ca, N, etc.
(3) Note. When a radical is indicated in a subclass title, (e.g., sulfide, carbonate, phosphate, etc.), all forms thereof (i.e., the acid forms, such as HSO3-, HCO3-, HPO42-, H2PO4-) are also included within the definition, unless specifically stated otherwise. Generally, however, in the metal recovery area, subclasses 1+, only the radicals listed in the titles are involved and no other. For example, in subclass 36, "sulfating" means that only the sulfate (SO42-) radical is intended. In the remaining areas of the schedule all forms of the radical are generally intended.
(4) Note. Use of a chemically reactive material, e.g., acid or base is considered to involve a chemical treatment for this class, unless there is evidence to the contrary or where otherwise stated, (see subclass 210, reference to Class 95, for example).
(6) Note. Processes of purification which involve oxidation or chemical conversions of impurities, as well as those processes wherein the compound sought to be purified is first converted into some other form or derivative from which it is reverted to the original compound are also considered to be chemical treatment.
(7) Note. Processes of preparation of an inorganic compound or a nonmetallic element which include chemical treatment or preparation are classified in the appropriate compound or element subclass, unless a process subclass is specifically provided therefor under the compound or element subclass, even though combined with a purely physical operation precedent, subsequent, or both. However, a patent containing a claim to the product and a claim to the process of manufacture thereof, which process is indented under the product subclass, should be placed in the outdent (product subclass) and cross-referenced to the other. A claim to the product of making it is considered to be a product claim and should be classified in the appropriate product subclass and cross referenced to the process, if any.
(8) Note. Processes of preparation or treatment of inorganic compounds and nonmetallic elements which involve only physical treatment except for extracting, leaching or dissolving, per se, are classified in 23, Chemistry: Physical Processes, subclasses 293+ unless specifically provided for in some other main class. When extracting, leaching or dissolving processes are combined with significant crystallization steps, see Class 23, Chemistry: Physical Processes, subclasses 295+. Also see Class 23, Chemistry: Physical Processes, subclasses 293, 294 and 306 thru 308 for extracting, leaching or dissolving which may be combined with physical steps therein provided for. When patents include claims to a physical process and also claims to the compound or element treated, the original patent is classified in Class 423 in the appropriate subclass providing for the compound or element and cross-referenced to the appropriate process subclass in Class 23.
(9) Note. Varying the amount of water of crystallization or hydration is considered to involve a chemical reaction; merely changing from one crystalline form to another or from or to a non crystalline form is not considered to be a chemical reaction.
(10) Note. The combination of a nominal molding step and a chemical reaction is properly classified in Class 423. See definition of Class 264 for examples of "nominal" molding steps.
(11) Note. The combinations of a chemical reaction and magnetic separation is in Class 423.
(12) Note. A compound having water of hydration or crystallization attached thereto is classified with the basic compound unless there is a specific subclass provided for the hydrated compound. In this respect, the water (H2O) is treated as a unit and the hydrogen and oxygen therein of themselves do not cause classification in the oxygen area (579+) or the hydrogen area (644+).
(13) Note. A material or substance containing a metal or other element in a range of absolute values or mole ratios compared to another metal or other element, (e.g., 1.7-3.5 parts, mole ratio of M to X in the range of 1.1-3.7, etc.), will be considered proper for a composition class; if the metal or other element is present in specifically defined whole integer values, (e.g., 1, 2 or 3 parts, etc.), it will be considered a compound properly classified in Class 423. Similarly if atoms or molecules in a chemical formula are not present as whole small integer values or cannot be multiplied by a factor to yield integer values, then the substance represented by the formula will be considered to be a mixture or composition classifiable in a locus other than Class 423. However, see (1) Note in subclass 328 for exception to general rule stated above.
(14) Note. A water solution (whether preserved or not) of a Class 423 compound or element is classified in Class 423 unless its use is claimed or a single use is disclosed, in which case classification in the use class is indicated.
(15) Note. When a patent includes (1) a single claim directed to the formation of 2 or more desired products, or (2) plural, equally comprehensive claims defining processes or products wherein the individual claims would be classified in separate classes, the following rules apply: (1) As between Class 423 and other classes providing for compounds the patent is placed in Class 423. (2) As between Class 423 and Class 75 the patent is placed in Class 75. (3) As between Class 423 and classes providing for compositions, the patent is placed in the composition class.
(16) Note. Where a process includes a step of recovery of the energy in a fluid (e.g., expansion in a motor to produce mechanical or electrical power, use in a heat exchanger for utilization outside of the process, etc.) the intent of the patentee must be considered for proper classification. If the intent is to conduct the chemical reaction, make the product or purify a gas or separate a mixture as provided for in Class 423 and recovery of the energy in the fluid is simply for economic reasons the classification is proper for Class 423. If the intent of the chemical reaction, is to increase the energy level in the fluid for the purpose of producing the mechanical or electrical power, then classification in another main class is indicated. If the power produced is used in the process, e.g., pumping, refrigeration, heat exchange, etc. classification in Class 423 in proper.
(17) Note. The rules for determining Class placement of the Original Reference (OR) for claimed chemical compositions are set forth in the Class Definition of Class 252 in the section LINES WITH OTHER CLASSES AND WITHIN THIS CLASS, subsection COMPOSITION CLASS SUPERIORITY, which includes a hierarchical ORDER OF SUPERIORITY FOR COMPOSITION CLASSES.

SECTION III - SUBCLASS REFERENCES TO THE CURRENT CLASS

SEE OR SEARCH THIS CLASS, SUBCLASS:

1+,for treating mixture to obtain metal containing compound (see the Class Definition, above).
265+,.for products or processes comprising a compound or a nonmetallic element physically interrelated with another substance which serves to improve, protect or modify the product, which substance does not take part in the reaction, which makes the product, but is added to the reaction or to the product or is made by a separate and distinct reaction.
658.5,for extracting, leaching or dissolving processes.

SECTION IV - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

23Chemistry: Physical Processes,   for processes of preparing or treating inorganic compounds or nonmetallic elements which involve only physical treatments except for extracting, leaching, or dissolving, per se, and not specifically provided for in some other class; for processes for analysis which involve a chemical reaction.
48Gas: Heating and Illuminating,   for processes for making heating and illuminating gas in general and processes and apparatus for purifying a heating and illuminating gas; processes involving a chemical reaction for making or purifying heating or illuminating gas consisting of a single element or organic compound, per se, are classified in Class 423.
53Package Making,   appropriate subclasses especially subclasses 428+ for methods of manufacturing chemical compounds followed by a subsequent packaging step.
65Glass Manufacturing,   for a process or apparatus for chemically manufacturing silicon or silicon dioxide (arbitrarily considered to be glass for Class 65) combined with significant shaping or heat treating.
71Chemistry: Fertilizers,   appropriate subclasses for compositions, and processes of making such compositions, having a nutrient action on plant growth. See (1) Note in the definition of Class 71 and (13) Note and (15) Note in the definition of Class 423 for lines between these two classes.
75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   the line with the Class 75, Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures, is generally as follows: Class 75 provides for metals and processes for their manufacture. Class 423 provides for chemically modifying metal bearing compositions to form intermederiary products which comprise inorganic compounds even if intended for subsequent reduction to free metals. When it is not clear from the claimed disclosure whether the product produced is an intermediary of a free metal, it is assumed to be intermediary. A smelting process is assumed to produce a free metal unless otherwise stated. Class 75 provides for ore beneficiating processes which claim a sintering or agglomerating step, even though the production of a free metal is not claimed, and compounding of ingredient to make a composition which is in better form for pyrometallurgy, even though some chemical reaction is involved. Patents including claims classifiable in Class 423 and equally comprehensive claims classifiable in Class 75 are classified in Class 75 and cross-referenced to Class 423. Processes resulting in the production or separation of undesired metallic material,e.g, impurities, during the manufacture of Class 423 compounds are classified in Class 423. If the metal is a desired material, however, the patent is classified in Class 75. See also the note to Class 420, Alloy or Metallic Composition below. As between Class 75 and Class 423, intermetallic compounds are in Class 75. Processes resulting in the production or separation of undesired metallic material, e.g., impurities, during the manufacture of Class 423 compounds are classified in Class 423. If the metal is a desired material, however, the patent is classified in Class 75.
95Gas Separation: Processes,   for processes of a purely physical nature involving steps resulting in separation of a gas from a fluid mixture comprising (a) a gas and solid or liquid particles entrained therein, (b) a liquid and gas entrained therein, or (c) a plurality of gases. For patents to be placed in Class 423, a particular chemical must be claimed and the chemical reaction must be inherent or disclosed. Broadly reciting the separating material as a "chemical" or as "gas purifying material" does not exclude the patent from Class 95. Absorption and adsorption are not considered chemical reactions in this respect. Processes for separating a gaseous fluid mixture having therein ammonia (NH3) or acid anhydrides (e.g., CO2, SO2, etc.) by contacting the gaseous fluid mixture with water and thus dissolving these gases out of the gaseous fluid mixture are in Class 95, notwithstanding the fact that a chemical reaction occurs in the solution and that ammonium hydroxide or the acids are formed. See also, search class note to Class 95 in Class 423, subclass 210 .
106Compositions: Coating or Plastic,   appropriate subclasses for coating or plastic compositions not otherwise provided for. For the line between Classes 106 and 423. In regard to materials and ingredients, e.g., pigments, see the note to the definition of Class 106 under the heading "Materials or Ingredients". See also (13) Note and (15) Note in the definition of Class 423 and (4) Note in subclass 265 of that class.
117Single-Crystal, Oriented-Crystal, and Epitaxy Growth Processes; Non-Coating Apparatus Therefor,   for processes and non-coating apparatus for growing therein-defined single-crystal of all types of materials, including inorganic or organic.
134Cleaning and Liquid Contact With Solids,   appropriate subclasses, especially subclasses 2+ for the process of treating a mixture to remove foreign matter from the surface. The line between this Class 134 and Class 423 is as follows: in Class 423 the intent is to recover a metal compound from a mixture thereof, while in Class 134, the intent is merely to clean the mixture, whether or not the removed foreign matter is later treated to recover valuable by-products.
148Metal Treatment,   for processes for making case hardened metals and the corresponding products (e.g., carbided or nitrided metals) in which a metal is treated so as to form the nitride or carbide of the metal in more or less as a layer thereon, but which layer varies in composition towards the inside, the intention being to form case hardened metal, not to form a definite compound for recovery thereof.
162Paper Making and Fiber Liberation,   appropriate subclasses for process of chemically preparing or recovering inorganic compound with a fiber liberation step, and especially subclasses 29+ for processes of regenerating, for purposes of reusing, a fiber treating liquor, even though a compound or nonmetallic element for Class 423 is recovered. For the line between this Class 162 and Class 423 in regard to regeneration, the intent of the disclosure must be considered. If there is an intent to regenerate, reconstitute, reclaim or recycle the waste or used liquor being treated, whether or not a Class 423 product is recovered, classification is in Class 162.
201Distillation: Processes, Thermolytic,   appropriate subclasses for a process of carbonizing solid carbonaceous material, or for calcining coke to produce a coke or other impure carbon containing material, not otherwise provided for. A document having claims to both the process of coking and the additional steps of producing carbon black will be classified in Class 423 and cross referenced to Class 201.
203Distillation: Processes, Separatory,   for a process of separating a liquid mixture by vaporizing and condensing a portion thereof to isolate in the distillate or in the residue a relatively pure compound which was present as such in the original mixture, and for a process including a chemical reaction and a separatory distillation operation when the chemical reaction merely facilitates the isolation by the distillation process of a pre-existing substance in the original mixture. Class 423, Inorganic Chemistry, takes a process of preparing a compound and isolating it by a separatory distillation process or vaporizing a mixture and contacting the vaporous mixture with a substance which purified the mixture and prepares a compound for that class.
204Chemistry: Electrical and Wave Energy,   for processes of producing an inorganic compound or nonmetallic element by directly employing electrical or wave energy. The general line between this Class 423, and Class 204 is as follows: Class 423 provides for (1) process steps falling within the definition of Class 204 wherein a simultaneous or subsequent chemical reaction takes place which modified the product of the Class 204 to produce a different compound or element, and (2) branching processes wherein one of the branches comprises a process falling within the definition of Class 204 and at least one branch falls within the definition of Class 423. Class 204 takes processes wherein an initial or preparatory reaction of the type provided for in Class 423 is followed by process step of the type provided for in Class 204 which modifies the product of the initial reaction. In processes where a useful by-product is formed, the patent is classified accordingly.
(1) Note. If electrolysis takes place in a reagent which immediately reacts with a product of the electrolysis to yield a Class 423 product, classification is proper for Class 423.
209Classifying, Separating, and Assorting Solids,   appropriate subclasses, for processes of separating a mixture of compounds by magnetic action. However, processes which include both a chemical reaction and a magnetic separation are classified in the appropriate chemical class, e.g., Class 423, etc.
210Liquid Purification or Separation,   for chemical processes where the main intent is to purify a liquid, not to purify or recover a compound or nonmetallic element for Class 423, in regard to treatment of an effluent or waste liquor, the intent of the disclosure must be considered. If it be the main intent to purify the effluent liquor for disposal, classification is in Class 210 even though a product for Class 423 is recovered as an incident to the purification. If the main intent is to treat the effluent to recover a Class 423 product then classification in Class 423 is indicated. If the disclosure contains both intentions and it cannot be determined which is the primary intention, then classification is in Class 423 with cross reference to Class 210 where necessary.
252Compositions,   appropriate subclasses, for compositions of matter not otherwise provided for. See the definitions of Class 252 for its scope and the notes thereto for classification of other compositions. See also (13) Note and (15) Note in the definition of Class 423.
260Chemistry of Carbon Compounds,   appropriate subclasses, for claimed chemical processes in which an organic compound is the end result, even though the intent is to make an inorganic compound from this organic intermediate. However, a process which results in several different chemical compounds, one of which is classifiable in Class 423 and another is classifiable in Class 260, is classified in Class 423 and cross referenced into Class 260, except where the compound classifiable in Class 423 is only incidentally produced by the reaction, such as, for example, HC1 and is not an objective of the process.
376Induced Nuclear Reactions: Processes, Systems, and Elements,   for appropriate subclasses for changes in the chemical nature of materials brought about by nuclear reactions; and subclasses 156+ and 323+ for production of materials, other than or in addition to the conversion of nuclear fuel, by means of nuclear reactions.
420Alloys or Metallic Compositions,   appropriate subclasses for alloys, intermetallic compounds or compounds or composition containing a continuous phase of metal and methods of making them. See the class definition of Class 420 for the line between Class 420 and Class 75 for processes fo making alloys.
422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 1 through 44for processes for disinfecting, deodorizing, preserving, or sterilizing. Inorganic compounds or nonmetallic elements claimed with an additive which only serves to preserve the product are in Class 423. See also the notes in Class 423, subclasses 265+ and subclasses 45+ for chemical reactors and apparatus for carrying out chemical physical processes.
424Drug, Bio-Affecting and Body Treating Compositions,   appropriate subclasses for a Class 423 product combined with an additive which is claimed or solely disclosed as having a Class 424 utility. A Class 423 product having combined therewith an additive which protects the product, itself against biological attack is proper for Class 423, see subclasses 265+ .
426Food or Edible Material: Processes, Compositions, and Products,   subclasses 160+ , for baking powder compositions, which in some cases are made to deliberately contain impurities to stabilize the same and to cause proper reaction rates. In many instances, the compound is calcium acid pyrophoshate and the impurity is a calcium or aluminum compound.
428Stock Material or Miscellaneous Articles,   appropriate subclasses, for metallic compounds having specific outer structure, especially subclasses 379+ for a structurally defined or coated rod, strand, fiber or particle which may include a metal compound; subclasses 432 and 469+ for a non structural composite web or sheet including a layer of a metal compound.
429Chemistry: Electrical Current Producing Apparatus, Product, and Process,   subclasses 188+ for electrolyte compositions; subclass 247 for materials used to make a battery separator; and other appropriate subclasses having compositions combined with structure.
432Heating,   subclasses 1+ , for a residual process of heating. The line between Classes 423 and 432 is generally as follows: Class 423 takes heating processes which involve a chemical reaction to produce an inorganic compound or nonmetallic element. Materials identified by, terms such as "lime", "limestone" and "gypsum", are considered to be compounds for Class 423, but terms such as "cement" and "clay" are not. Residual processes which do not include a chemical reaction or do not result in a compound are in Class 432. The terms "calcining", "burning", "removing water of hydration", etc. are considered to involve a chemical reaction.
435Chemistry: Molecular Biology and Microbiology,   for processes of making separating or purifying compounds or elements by operations that include fermentation, and compositions and apparatus that are specialized for use therein and processes of making such compositions for such use.
504Plant Protecting and Regulating Compositions,   appropriate subclasses for compositions, and processes of making such compositions, having a stimulating or regulating action on plant growth. See (13) Note and (15) Note in the definition of Class 423 for lines between these two classes.
505Superconductor Technology: Apparatus, Material, Process,   subclasses 100+ for high temperature (Tc 30 K) superconducting materials, per se, or subclasses 300+ for processes of producing same.
506Combinatorial Chemistry Technology: Method, Library, Apparatus,   for a chemical library or a process of creating said library.
585Chemistry of Hydrocarbon Compounds,   appropriate subclasses for a claimed chemical process to synthesize a hydrocarbon. When a process produces an inorganic compound for Class 423 and a hydrocarbon compound for Class 585, both of which are intended to be recovered, the patent is classified as an original in Class 423 and cross-referenced to Class 585.
588Hazardous or Toxic Waste Destruction or Containment,   appropriate subclasses for the process of chemical destruction of hazardous or toxic waste, other than gas (except chemical warfare agents), by way of incineration heating or other chemical reactions when the destruction of the waste is the intended purpose. Class 423 takes all intended production or recovery of marketable products in the form of inorganic compounds or elements, and subclasses 210+ provide for the chemical destruction of gaseous hazardous or toxic waste (except chemical warfare agents). Note that subclasses 245.1+ provide for an organic component.

SECTION V - GLOSSARY

Terms used throughout the schedule and definitions are to have the meanings ascribed below. In some instances all the limitations found below may not have been included in the subclass definitions; all discrepancies should be resolved in favor of the following definitions.

ABSORPTION

The ability of a substance to retain or concentrate gases, liquids or dissolved substance (absorbate) within its bodies.

ADSORPTION

The ability of a substance (usually a solid) to retain or concentrate gases, liquids or dissolved substances (adsorbate) upon its surface.

ALKALI METALS

The metal elements of the first group of the periodic system, consisting of Li, Na, K, Rb, Cs.

ALKALINE EARTH METALS

The metal elements in Group II A of the periodic system, consisting of Mg, Ca, Sr, Ba.

BINARY COMPOUND

A chemical compound consisting of 2 elements only with 2 or more atoms; e.g., NaC1, FeC13, Fe304, etc.

CHALCOGEN

Also known as chalcogenide(s), the elements oxygen, sulfur, selenium, tellurium and polonium.

CATALYST

A substance which either increases or decreases the speed of a chemical reaction without itself undergoing a permanent change.

COMPLEX COMPOUND

A chemical combination of two or more compounds or ions; e.g., 4 KCN and Fe (Cn)2 give the complex compound K4Fe (Cn)6; 2 HF and Si F4give the complex acid H2 Si F6. An electrically charged radical or group of atoms, e.g., Cu (NH3) 2+, is a complex ion.

COMPOUND

The elements or compounds comprising a material or produced from it by analysis.

COMPOUND

A substance whose molecules consist of unlike atoms, whose constituents cannot be separated by physical means, whose properties are entirely different from those of its constituent elements and which contains definite proportions of its constituent elements, depending on their atomic weights.

FLOTATION

A process for the concentration of selective separation of components of ores by grinding the ores with a frothing agent, floating them on water and agitating the mixture with compressed air, causing the wet gangue (earthy portion of the ore) to settle and permitting the concentrated ore to be skimmed off.

FLUIDIZED BED

A mass of solid particles maintained in a state of constant turbulent motion in a gas stream, resulting in a suspension of finely divided particles in a stream of gas thus increasing the surface area and therefor surface activity of the particles.

HALOGENS

Also known as halogenides, the nonmetallic elements of the seventh group of the periodic system and consisting of F, C1, Br, I, At.

INERT GASES

The noble gases of the zero group of the periodic system, consisting of He, Ne, Ar, Kr, Xe, Rn, which have no valency and combine only with great difficulty, if at all, with other elements.

ION EXCHANGE

A process in which ions are chemically transferred from a material to a liquid or solid separatory substance or exchanger which, because of its chemical structure of loosely bound ions, has an affinity for certain ions and gives up some of its own ions to the material. The exchange occurs between ions of like charge; the exchanger substance can usually be regenerated by passing another material through it to elute the previously sorbed ions and replace them with the original kind of loosely bound ions. These ion exchange substances are usually resins or zeolites or chelates.

IRON GROUP METALS

Those metals in the central part of the third period of the periodic system consisting of Fe, Co and Ni, all of which form colored salts and 2 or more series of compounds.

LEACHING

The process of extracting or dissolving a soluble component from a mixture by contacting the mixture with a solvent, resulting in dissolution or solution of the solubles and leaving an insoluble material.

(Note. Solution of a substance in a normally solid, molten material is not considered to be "leaching" as defined above.)

LIQUID-LIQUID EXTRACTION

The process of transferring a substance (fluid or solid) from one liquid phase in which it is dispersed or dissolved to a second liquid phase which is immiscible with the first liquid.

NONMETALLIC ELEMENTS

The electronegative elements on the right of the periodic system, which generally exist in several stages of oxidation and whose oxides form acids. See main class definition for list of nonmetals for this class.

ORGANIC COMPOUND

A compound as defined in the definition of Class 260, Chemistry of Carbon Compounds as qualified by (34) Note.

PLATINUM METALS

A group of noble metals that occur together in nature and form 2 groups in the periodic system, i.e., Ru, Rh, Pd, Os, Ir and Pt.

PROMOTER

A substance which stimulates or aids the effect of a catalyst.

RADIOACTIVE

Able to give off rays by spontaneous disintegration. The radioactive elements are usually those having an atomic number of 84 or greater and the phenomenon of radioactivity is not affected by chemical or physical influences.

RARE EARTHS

The oxides of the rare earth metals consisting of the elements having atomic numbers 21, 39, 57-71, inclusive.

RECOVERY

The extraction or removal of a valuable constituent from a raw material, by-product or waste product.

REFRACTORY METALS

Those metals in Group IV B, V B and VIB of the periodic system, consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, some of which are used in making bricks or cement which resist heat and are slow to soften.

TERNARY COMPOUND

A chemical compound consisting of 3 elements only, such as NaOH, H2SO4, KCN, etc.

VOLATIZING

Converting a normally solid or liquid material into a gas or vapor state; mere volatization of water or a solvent is excluded under this definition.

SUBCLASSES

[List of Patents for class 423 subclass 1]    1TREATING MIXTURE TO OBTAIN METAL CONTAINING COMPOUND
 This subclass is indented under the class definition.  Processes wherein a mixture is chemically treated to obtain or recover a compound of a metal contained in the original mixture as an element, a compound or a precursor transmutable to the metal.
(1) Note. The chemical reaction need not involve the desired metal, it may be with another constituent of the mixture for easier separation of the desired compound.
(2) Note. The following are assumed to be mixtures unless otherwise specifically disclosed or stated: the slightly impure compound, ores, metalliferous materials, minerals, alloys, amalgams, scrap metal, clay, metals coated, plated or jacketed on other metals, or on other material, spent or waste liquors (regenerating, purifying or recovering from) limestone, flue dust, gypsum.
(3) Note. It must be the inventor"s intent that a metal in compound form be obtained, but it is not necessary that this compound be separated from the mixture. For example, the process of changing Fe2O3in ore to Fe3O4by magnetic roasting in order to obtain a better form for smelting is properly classified in this group of subclasses (151+). Further the initial or starting material must be considered in order to determine whether or not the claimed process is for isolating a metallic compound from a mixture. Where two compounds are first mixed together, as disclosed, and subsequent to a chemical reaction, a separation is made, classification of such a process is not in this group of subclasses even though the initial step of mixing is not claimed; such a patent may be classified in other areas of this class on other features. Also, where a mixture results from an intermediate step in a process for making a product and the mixture is separated, that is not considered as treating a mixture to obtain metal compounds for this group of subclasses.
(4) Note. Changing the form of a compound to render it less effective as an impurity or to make it nondetrimental is not considered to be recovery under this definition. Further, converting part of a mixture which is considered an impurity to the desired part is not considered to be recovery under this definition. For example converting the Na2CO3in a mixture with Na2S to Na2S, therefore resulting in all Ma2S, is not recovery.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   appropriate subclasses, for a process of (1) purifying mixtures and obtaining the free metal, (2) making agglomerates for metallurgical purposes, (3) smelting (which is assumed to result in the free metal unless otherwise specifically disclosed), (4) cementation of one metal on another, (5) deposition of a metal on another material (6) making an impure metal but in the elemental form. As between Classes 423 and 75, the claimed process which goes to the metallic compound indicates classification in Class 423, whether the purpose is to commercially use the compound or to later dissociate the compound to obtain the free metal, while the additional claimed step of yielding the free metal brings the claim to Class 75; in the situation where some of the claims recite the metal and others recite the metallic compound, the most comprehensive or combination claim controls (free metal) and the document is classified in Class 75; similarly if the intent is to obtain both the metal and the compound and both processes are claimed the patent goes to Class 75, as an original. If a metal which is definitely only an impurity is removed as an element and the desired metal is in compound form, classification of the original is in Class 423.
134Cleaning and Liquid Contact With Solids,   subclasses 2+ , for a process of removing foreign matter from a metallic substance, where the intent is merely for cleaning purposes, not to recover a metal containing compound.
209Classifying, Separating, and Assorting Solids,   appropriate subclasses, for separating parts of a solid mixture where no chemical reaction is involved.
216Etching a Substrate: Processes,   for etching of any material not otherwise provided for, and including composite substrates or mixtures.
241Solid Material Comminution or Disintegration,   for ore crushing and physical separation.
299Mining or In Situ Disintegration of Hard Material,   for in situ chemical separation.
420Alloy or Metallic Compositions,   appropriate subclasses for alloys, intermetallic compounds or composition containing a continuous phase of metal and methods of making them.
432Heating,   subclasses 1+ , for a residual process of applying heat to a material.
  
[List of Patents for class 423 subclass 2]    2Radioactive metal (At. No. 84+ or radioactive isotope of another metal)
 This subclass is indented under subclass 1.  Processes in which the compound comprises a metal which exhibits spontaneous nuclear disintegration with emission of radioactive particles, either as (1) the naturally unstable metal which has an atomic number of at least 84, or (2) a metal which has been treated to render an isotope thereof radioactive; see Glossary.
(1) Note. Compounds of the trans-actinide elements, i.e., those having atomic numbers greater than 103 will be found in this group of subclasses.
(2) Note. Patents wherein the claims are directed to making an element radioactive or to forming a different isotope of a radioactive element are classified in Class 376, Induced Nuclear Reactions: Processes, Systems, and Elements, subclasses 156+ even when the element is in compound form.

SEE OR SEARCH THIS CLASS, SUBCLASS:

249+,for a radioactive compound, element or isotope, per se.
  
[List of Patents for class 423 subclass 3]    3Actinide series metal (At. No. 89+)
 This subclass is indented under subclass 2.  Processes in which the radio-active compound comprises a metal of the actinide series, i.e., one having an atomic number of 89 or greater.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   for processes in general of obtaining pure metal values in a metallurgical process and particularly subclass 84.1 for pyrometallurgical processes for obtaining actinide and trans-actinide series metals. Production of the metal, e.g., uranium, plutonium, etc., compounds or concentrates as products even if disclosed for metallurgical purposes are classified in this and indented subclasses.
204Chemistry: Electrical and Wave Energy,   appropriate subclasses for electrical or wave energy preparation, separation, or recovery of actinide series products. Also see the References to Other Classes section of the Class 204 definition for the general class line between Class 204 and Class 423.
205Electrolysis: Processes, Compositions Used Therein, and Methods of Preparing the Compositions,   subclasses 43+ for electrolytic processes involving an actinide series element or compound, including preparation, separation, or recovery of actinide series products.
376Induced Nuclear Reactions: Processes, Systems, and Elements,   for processes of producing a reaction product by an impact or bombardment of a nucleus and in subclasses 189 , 195, 198, and 201 for such processes followed by product treatment for recovery or separation.
420Alloys or Metallic Compositions,   subclasses 1+ for alloys, metallic compositions or intermetallic compounds containing an actinide or transactinide series metal.
  
[List of Patents for class 423 subclass 4]    4Removing cladding or coating from fuel element
 This subclass is indented under subclass 3.  Processes in which the actinide metal comprises a nuclear fuel element and is obtained by treating the fuel element to remove the covering or casing material therefrom.

SEE OR SEARCH CLASS:

252Compositions,   subclasses 625+ , for processes producing a useful composition containing actinide series elements and such compositions.
376Induced Nuclear Reactions: Processes, Systems, and Elements,   subclasses 409+ for the structure of the fuel element, per se.
534Organic Compounds,   for organic actinide compounds and methods of making the same, in particular subclasses 11+ for carbocyclic or acyclic actinide compounds. See also main class definition of Class 260.
  
[List of Patents for class 423 subclass 5]    5Fusing
 This subclass is indented under subclass 3.  Processes in which the treatment includes the step of melting material or using molten material.
  
[List of Patents for class 423 subclass 6]    6Ion exchanging or sorbing
 This subclass is indented under subclass 2.  Processes which include (1) attracting and retaining a component of the mixture by contact with an ion exchange substance or (2) using a substance which has an affinity for and retains a selected component or portion of the mixture being treated; see Glossary.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   subclasses 90+ for processes of gas separation using solid sorbents, per se.
210Liquid Purification or Separation,   subclasses 24+ , for processes of separation in general by ion exchange or sorption.
  
[List of Patents for class 423 subclass 7]    7Organic synthetic resin
 This subclass is indented under subclass 6.  Processes in which the substance is an organic synthetic resin.
(1) Note. For the definition of "synthetic resin", see Class 520, subclass 1.
  
[List of Patents for class 423 subclass 8]    8Liquid-liquid extracting
 This subclass is indented under subclass 3.  Processes which include the step of selectively dissolving a compound in one of two contacting immiscible liquids for separation; see Glossary.

SEE OR SEARCH THIS CLASS, SUBCLASS:

24,54, 63, 70, 112, 139, 157, and 181, for processes of treating mixtures including a desired metal to form a compound of the metal, in which the step of liquid-liquid extraction if utilized.
  
[List of Patents for class 423 subclass 9]    9Organo-nitrogen solvent
 This subclass is indented under subclass 8.  Processes in which one of the immiscible liquids is an organic solvent containing nitrogen, e.g., amines, etc.

SEE OR SEARCH CLASS:

260Chemistry of Organic Compounds,   appropriate subclasses for nitrogen containing organic solvents.
  
[List of Patents for class 423 subclass 10]    10Organo-phosphorus solvent
 This subclass is indented under subclass 8.  Processes in which one of the liquids is an organic solvent which contains phosphorus.

SEE OR SEARCH CLASS:

260Chemistry of Organic Compounds,   appropriate subclasses for phosphorus containing organic solvents.
  
[List of Patents for class 423 subclass 11]    11Forming insoluble substance in liquid
 This subclass is indented under subclass 3.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 12]    12By coprecipitating with carrier
 This subclass is indented under subclass 11.  Processes in which another substance is caused to become insoluble and acts to carry out ions of the actinide series metal while coming out of solution.
(1) Note. In some instances, the carrier compound acts to sorb the additional ions.
  
[List of Patents for class 423 subclass 13]    13Carrier contains bismuth
 This subclass is indented under subclass 12.  Processes in which the other compound comprises bismuth.
  
[List of Patents for class 423 subclass 14]    14Carrier contains lanthanum
 This subclass is indented under subclass 12.  Processes in which the other compound comprises lanthanum.
  
[List of Patents for class 423 subclass 15]    15Forming compound containing plural metals or metal and ammonium
 This subclass is indented under subclass 11.  Processes in which a compound formed contains the ammonium (NH4+) radical or another metal in addition to an actinide series metal.
(1) Note. In this subclass will be found, for example, double salts of uranium compounds, i.e., those containing at least two cations and which crystallize as a single substance but ionize as two substances, and compounds of uranic acid (U2O72-).
  
[List of Patents for class 423 subclass 16]    16Forming peroxide (e.g., U04, etc.)
 This subclass is indented under subclass 11.  Processes which include forming a peroxide such as UO4, etc.
  
[List of Patents for class 423 subclass 17]    17Carbonate leaching
 This subclass is indented under subclass 11.  Processes which include making a separation by using a carbonate as an active ingredient to leach, wash, or dissolve; see Glossary.
  
[List of Patents for class 423 subclass 18]    18Acid leaching
 This subclass is indented under subclass 11.  Processes which include making a separation by using an acid as an active ingredient to leach, wash, or dissolve; see Glossary.
  
[List of Patents for class 423 subclass 19]    19Volatizing
 This subclass is indented under subclass 3.  Processes including the step of causing a normally liquid or solid substance in element or compound form to be changed into a gas or a vapor; see Glossary.
(1) Note. Mere volatization of water or a solvent to concentrate a solution is not included under this definition; classification of such a process is based on other features.
  
[List of Patents for class 423 subclass 20]    20Acid leaching
 This subclass is indented under subclass 3.  Processes which include making a separation by using an acid as an active ingredient to leach, wash, or dissolve; see Glossary.

SEE OR SEARCH THIS CLASS, SUBCLASS:

18,for similar processes which include acid leaching in combination with forming an insoluble substance in a liquid.
  
[List of Patents for class 423 subclass 21.1]    21.1Rare earth metal (At. No. 21, 39, or 57-71):
 This subclass is indented under subclass 1.  Processes in which the compound comprises one of the metals known as the "rare earth metals" and which has an atomic number of 21, 39, or 57-71, inclusive.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415for the treatment of hazardous or toxic waste containing rare earth metals (atomic numbers 21, 39, or 57-71).
  
[List of Patents for class 423 subclass 21.5]    21.5Ion exchanging or liquid-liquid extracting:
 This subclass is indented under subclass 21.1.  Processes which include the step of (a) attracting and retaining a compound of the mixture by contact with an ion exchange substance or (b) selectively dissolving a compound in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 22]    22Platinum group metal (Ru, Rh, Pd, Os, Ir, or Pt)
 This subclass is indented under subclass 1.  Processes in which the compound comprises one of the metals known as the platinum group metals, i.e., ruthenium rhodium, palladium, osmium, iridium or platinum.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 407+ , 412 and 249-260 for the destruction or containment of hazardous or toxic waste containing platinum group elements (ruthenium, rhodium, palladium, osmium, iridium, or platinum).
  
[List of Patents for class 423 subclass 23]    23Group IB metal (Cu, Ag, or Au)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises copper, silver or gold.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 100 , 117 and 118, for hydrometallurgical processes wherein the metal values recovered consist of copper, silver or gold in elemental form.
556Organic Compounds,   subclasses 110+ for organo-metallo compounds containing copper, silver or gold or the processes for preparing such compounds.
588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste being volatilized or containing Cu, Ag, or Au.
  
[List of Patents for class 423 subclass 24]    24Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 23.  Processes, which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance or (2) selectively dissolving a component in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 25]    25Sorbing or magnetic separating
 This subclass is indented under subclass 23.  Processes which include the step of attracting or retaining a component or portion of the mixture by means of magnetic lines of force or by selective adherence to the surface of a solid; see Glossary.
  
[List of Patents for class 423 subclass 26]    26Flotation
 This subclass is indented under subclass 23.  Processes which include the step of floating or causing concentrated metal values of the mixture to rise to the top and to be skimmed off while the earthy portions of the ore are permitted to settle; see Glossary.
  
[List of Patents for class 423 subclass 27]    27Leaching, washing, or dissolving
 This subclass is indented under subclass 23.  Processes, including a step of causing separation by leaching, washing or dissolving out; see Glossary.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 101+ , for a process of obtaining a pure elemental metal and including the step of leaching with a chemical.
  
[List of Patents for class 423 subclass 28]    28Specified particle size
 This subclass is indented under subclass 27.  Processes which specify a particular particle size or range for the starting mixture, the intermediate or the final product.
  
[List of Patents for class 423 subclass 29]    29With a cyanide compound
 This subclass is indented under subclass 27.  Processes in which one of the active leaching ingredients is a cyanide.

SEE OR SEARCH THIS CLASS, SUBCLASS:

371+,for a cyanide compound, per se, or the process of preparing such a compound where the starting material is substantially a pure substance.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclass 105 for the process of obtaining a pure elemental metal and which includes the step of leaching with a cyanide compound.
  
[List of Patents for class 423 subclass 30]    30And pressurizing
 This subclass is indented under subclass 29.  Processes in which a pressure above atmospheric is employed while the leaching is being effected.
(1) Note. Included under this definition is the use of gas under pressure contacting the mixture either above the surface thereof or as a submerged blast.
  
[List of Patents for class 423 subclass 31]    31And agitating
 This subclass is indented under subclass 29.  Processes, wherein the reaction mixture is subjected to stirring, vibration or mixing while being leached.
(1) Note. The agitation of the mixture may be effected by any means, e.g., fluid, mechanical or sonic, etc.
  
[List of Patents for class 423 subclass 32]    32With ammonia or ammonium containing compound
 This subclass is indented under subclass 27.  Processes in which one of the active leaching ingredients is ammonia or an ammonium compound.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclass 103 , for a process of obtaining a pure elemental metal and which includes the step of leaching with ammonia or an ammonium compound.
  
[List of Patents for class 423 subclass 33]    33Specified temperature
 This subclass is indented under subclass 32.  Processes wherein a specified temperature or range thereof is recited.
(1) Note. This subclass includes patents which specify a temperature preceding, during or following the leaching step.
  
[List of Patents for class 423 subclass 34]    34Forming insoluble substance in liquid
 This subclass is indented under subclass 27.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein, and comes out of solution or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Included under this definition of insolubilization is that wherein a substance crystallizes out of solution due to temperature or concentration change.
(2) Note. The compounds formed by the titles specifically set out in the indented subclasses need not be those which come out of the solution; they may remain soluble while others formed by the process precipitate out.

SEE OR SEARCH THIS CLASS, SUBCLASS:

42+,for a process of forming an insoluble substance in a liquid which process does not involve a leaching step.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 101+ for a process of obtaining a pure elemental metal, which includes the step of chemical leaching and which may involve precipitating a substance or causing it to come out of solution; and subclasses 106+ for a process of obtaining a pure elemental element by causing it or a compound thereof to come out of solution and which involves leaching with a cyanide compound.
  
[List of Patents for class 423 subclass 35]    35Forming oxide or carbonate
 This subclass is indented under subclass 34.  Processes in which an oxide or carbonate is formed.
  
[List of Patents for class 423 subclass 36]    36Sulfating
 This subclass is indented under subclass 34.  Processes which includes chemically forming a compound having the sulfate (SO42-) radical.
(1) Note. In this subclass may be found disclosures to double sulfates of a monovalent metal and a tri-valent metal.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 110 and 115+ for a process of obtaining a pure elemental metal and which involves the formation of a sulfate compound.
  
[List of Patents for class 423 subclass 37]    37Sulfiding
 This subclass is indented under subclass 34.  Processes which includes chemically forming a compound having the sulfide (S2-) ion.
  
[List of Patents for class 423 subclass 38]    38Halogenating
 This subclass is indented under subclass 27.  Processes which include chemically forming a halogen containing compound.
(1) Note. Included in this and the indented subclasses are methods of wet or dry chloridizing precedent to or subsequent to leaching.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 111+ for a process of forming a pure elemental metal which includes the step of chloridizing.
  
[List of Patents for class 423 subclass 39]    39Specified temperature
 This subclass is indented under subclass 38.  Processes in which a specific temperature or a range of temperatures is recited during at least part of the process either for the mixture or for a substance involved in the process.
  
[List of Patents for class 423 subclass 40]    40With chlorine gas or chlorinated water
 This subclass is indented under subclass 38.  Processes in which the halogen in the compound formed is chlorine and is provided by using as a reactant either chlorine gas or chlorinated water.
  
[List of Patents for class 423 subclass 41]    41Sulfating
 This subclass is indented under subclass 27.  Processes which include chemically forming a compound having the sulfate (SO42-) radical.

SEE OR SEARCH THIS CLASS, SUBCLASS:

36,for a process of forming a similar metal compound which includes the step of forming a sulfate as well as the steps of leaching or dissolution and causing a substance to become insoluble in, or precipitate out of a liquid or slurry.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 110 and 115+ for a process of obtaining a pure elemental metal which includes the step of sulfating.
  
[List of Patents for class 423 subclass 42]    42Forming insoluble substance in liquid
 This subclass is indented under subclass 23.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and other materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 108+ for a process of obtaining a pure elemental metal and which includes step of precipitation.
  
[List of Patents for class 423 subclass 43]    43Specified pH
 This subclass is indented under subclass 42.  Processes in which specific alkalinity or acidity is employed during the process.
  
[List of Patents for class 423 subclass 44]    44Volatizing copper, silver, or gold
 This subclass is indented under subclass 23.  Processes including the step of causing copper, silver or gold in either the elemental or compound form to pass into the form of a gas or a vapor; see Glossary.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 111+ for a process of obtaining a pure elemental metal which may include a step of volatizing a substance.
  
[List of Patents for class 423 subclass 45]    45Sulfating
 This subclass is indented under subclass 23.  Processes which include chemically forming a compound containing the (SO42-) sulfate radical.

SEE OR SEARCH THIS CLASS, SUBCLASS:

36,for a process in which a similar sulfate compound is formed, but in which also a substance is caused to come out of solution in a liquid or slurry and in which leaching is effected.
41,in which a similar sulfate compound is formed and in which leaching effected.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 110 and 115+ for a process of obtaining a pure elemental metal and which involves the formation of a sulfate compound.
  
[List of Patents for class 423 subclass 46]    46Halogenating
 This subclass is indented under subclass 23.  Processes which include chemically forming a halogen containing compound.

SEE OR SEARCH THIS CLASS, SUBCLASS:

38+,for a process of obtaining a similar metal compound in which a halogen containing compound is formed and in which the step of leaching or dissolution is included.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidatedr Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 110 and 111+ for a process of obtaining a pure elemental metal and which involves the formation of a chlorine containing compound.
  
[List of Patents for class 423 subclass 47]    47Desulfurizing or de-arsenating
 This subclass is indented under subclass 23.  Processes including the removal of sulfur or of arsenic from the mixture.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclass for a process of removing at least a portion of the sulfur or of the arsenic from an ore for the purpose of concentrating the metal values of the ores.
  
[List of Patents for class 423 subclass 48]    48Forming sulfide or matte
 This subclass is indented under subclass 23.  Processes which include forming a sulfide compound or a mixture of sulfides known as a matte.
  
[List of Patents for class 423 subclass 49]    49Group VIIB metal (Mn, Tc, or Re)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises manganese, technetium or rhenium.
(1) Note. Technetium does not occur naturally; it is a fission product of uranium. Compounds of technetium are known, however, e.g., Tc2°7, NH4Tc°4, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2+,for processes of treating mixtures to obtain radioactive group VIIB metal compounds and subclasses 249+ for the radioactive metal compound, per se.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing Mn, Tc, or Re.
  
[List of Patents for class 423 subclass 50]    50Forming insoluble substance in liquid
 This subclass is indented under subclass 49.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 51]    51Halogenating
 This subclass is indented under subclass 50.  Processes including the step of chemically forming a compound containing a halogen.
  
[List of Patents for class 423 subclass 52]    52Sulfating
 This subclass is indented under subclass 50.  Process including the step of forming a compound containing the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 53]    53Group VIB metal (Cr, Mo, or W)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises chromium, molybdenum, or wolfram (tungsten).

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste being volatilized or containing Cr, Mo, or W.
  
[List of Patents for class 423 subclass 54]    54Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 53.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance or (2) selectively dissolving a component in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 55]    55Forming insoluble substance in liquid
 This subclass is indented under subclass 53.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 56]    56Ammoniating or nitrating
 This subclass is indented under subclass 55.  Processes including the step of chemically forming a compound which contains the ammonium (NH4+) or nitrate (NO3-) radical.
  
[List of Patents for class 423 subclass 57]    57Sulfating
 This subclass is indented under subclass 55.  Processes including the step of chemically forming a compound having the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 58]    58Forming compound containing plural metals
 This subclass is indented under subclass 55.  Processes including the step of chemically forming a compound which contains at least two metals.
  
[List of Patents for class 423 subclass 59]    59Volatizing
 This subclass is indented under subclass 53.  Processes including the step of causing a normally solid or liquid substance in either elemental or compound form to be changed into a gas or a vapor; see Glossary.
  
[List of Patents for class 423 subclass 60]    60As a compound containing chlorine
 This subclass is indented under subclass 59.  Processes wherein the substance is a compound which contains chlorine.
  
[List of Patents for class 423 subclass 61]    61Forming compound containing plural metals
 This subclass is indented under subclass 53.  Processes including the step of chemically forming a compound which contains at least two metals.

SEE OR SEARCH THIS CLASS, SUBCLASS:

58,for process of forming a plural metal containing compound containing a Group VIB metal from a mixture, which process also includes forming an insoluble substance in a liquid.
  
[List of Patents for class 423 subclass 62]    62Group VB metal (V, Nb, or Ta)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises vanadium, niobium, or tantalum.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing V, Nb, or Ta.
  
[List of Patents for class 423 subclass 63]    63Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 62.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance, or (2) selectively dissolving a component in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 64]    64From organic liquids
 This subclass is indented under subclass 62.  Processes wherein the compound is separated from liquids which are organic compounds, i.e., those nonpolar compounds consisting of carbon and hydrogen with or without other elements (except for those compounds in which carbon plays an unimportant part, as carbonates) e.g., petroleum oils, etc.
  
[List of Patents for class 423 subclass 65]    65Forming insoluble substance in liquid
 This subclass is indented under subclass 62.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 66]    66Hydroxylating or hydrating
 This subclass is indented under subclass 65.  Processes including the step of chemically forming a hydroxide or a hydrate.
  
[List of Patents for class 423 subclass 67]    67Ammoniating or sulfating
 This subclass is indented under subclass 65.  Processes including the step of chemically forming a compound which contains the ammonium (NH4+) radical or the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 68]    68Leaching, washing, or dissolving
 This subclass is indented under subclass 62.  Processes which include leaching, washing, or dissolving out a portion of the mixture; see Glossary.
  
[List of Patents for class 423 subclass 69]    69Group IVB metal (Ti, Zr, or Hf)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises titanium, zirconium, or hafnium.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   especially subclasses 84+ for a process in which Ti, Zr, or Hf is reduced to metallic state from a compound thereof after a treatment to separate such compounds from mixtures.
588Hazardous or Toxic Waste Destruction or Containment,   subclasses 407 and 412 for the treatment of hazardous or toxic waste containing Ti, Zr, or Hf.
  
[List of Patents for class 423 subclass 70]    70Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 69.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance, or (2) selectively dissolving a component in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 71]    71Forming compound containing plural metals
 This subclass is indented under subclass 69.  Processes including chemically forming a compound which contains at least two metals.
  
[List of Patents for class 423 subclass 72]    72Halogen containing
 This subclass is indented under subclass 71.  Processes in which the compound also contains a halogen.
  
[List of Patents for class 423 subclass 73]    73Separating Group IVB metals from each other
 This subclass is indented under subclass 69.  Processes in which the mixture contains at least two members from the group comprising Ti, Zr, and Hf, and in which one of these members is recovered separately from any other.
  
[List of Patents for class 423 subclass 74]    74Utilizing fluidized bed
 This subclass is indented under subclass 69.  Processes in which solids are suspended in upward flowing gas or vapor, the upward force of the fluid on the solids being countered by gravity, resulting in the formation of a zone in which the particles are compacted into a dense phase; see Glossary.
(1) Note. The particles are in a state of hindered settling and the dense bed resembles a boiling liquid and above this dense bed some solids may be suspended in a dilute or dispersed phase.
  
[List of Patents for class 423 subclass 75]    75Volatizing
 This subclass is indented under subclass 69.  Processes which include the step of causing a normally solid or liquid substance in either elemental or compound form to be changed into a gas or vapor; see Glossary.

SEE OR SEARCH CLASS:

203Distillation: Processes, Separatory,   appropriate subclasses, especially subclasses 28+ for a process which includes a chemical reaction solely for the purpose of facilitating the isolation by distillation of a component of the original mixture. A process which includes vaporizing an impure mixture and then chemically treating the impure vapor to recover or separate therefrom a desired metal compound is classified in Class 423; see also reference to Class 203 in section III, Line and Search Notes.
  
[List of Patents for class 423 subclass 76]    76Titanium, zirconium, or hafnium
 This subclass is indented under subclass 75.  Processes in which titanium, zirconium or hafnium is volatized in elemental or compound form.
(1) Note. This subclass includes processes where an impure chloride is purified by distillation of the Group IVB metal chloride.
  
[List of Patents for class 423 subclass 77]    77Removing undesirable matter from vapor
 This subclass is indented under subclass 76.  Processes in which the vapor stream is treated to remove undesired materials, the Group IVB metal values remaining in vapor form during the separation.

SEE OR SEARCH THIS CLASS, SUBCLASS:

75,and 76, for a process in which either the undesirable material or the Ti, Zr, or Hf is volatilized, there being no separation of one from the other in the vapor stream.
  
[List of Patents for class 423 subclass 78]    78Specified physical form of feed solids
 This subclass is indented under subclass 76.  Processes in which volatilization takes place using solids which have been given a claimed physical shape; e.g., briquettes, pellets, etc.

SEE OR SEARCH CLASS:

264Plastic and Nonmetallic Article Shaping or Treating: Processes,   appropriate subclasses, for briquetting or otherwise shaping solid mixtures.
  
[List of Patents for class 423 subclass 79]    79Contacting feed solids with chlorine gas
 This subclass is indented under subclass 76.  Processes in which the vaporization of the Ti, Zr, or Hf is effected during contact of a solid feed material with gaseous chlorine.
  
[List of Patents for class 423 subclass 80]    80Chemically converting for physical solid-solid separation
 This subclass is indented under subclass 69.  Processes in which a chemical reaction is performed upon the mixture to enable two solid components of the mixture, usually of different compositions, to be more readily separated from each other by nonchemical methods and while the components are still in a solid-state.
(1) Note. Examples of solid-solid separation are: magnetic, gravity, centrifugal, etc. Solution (leaching) of one of the solids is not considered to be solid-solid separation for this subclass.

SEE OR SEARCH CLASS:

209Classifying, Separating, and Assorting Solids,   for methods and apparatus for solid-solid separation, per se, especially subclasses 3+ for treatments, preliminary to a solid-solid separation, which do not involve a chemical reaction.
  
[List of Patents for class 423 subclass 81]    81Treating with nitrogen or nitrogenous compound
 This subclass is indented under subclass 69.  Processes which include the step of reacting or contacting the mixture with a compound which contains nitrogen, e.g., nitric acid, ammonia, etc.
  
[List of Patents for class 423 subclass 82]    82Treating with sulfur or halogen containing acid
 This subclass is indented under subclass 69.  Processes which include the step of reacting or contacting the mixture with an acid which contains sulfur or a halogen, e.g., H2S, H2SO4, HC1, etc.
  
[List of Patents for class 423 subclass 83]    83Forming metallic iron or insoluble iron containing compound
 This subclass is indented under subclass 82.  Processes which include the formation of iron in elemental form or of an insoluble iron containing compound.
  
[List of Patents for class 423 subclass 84]    84Treating with compound containing alkali metal or alkaline earth metal
 This subclass is indented under subclass 69.  Processes which include the step of reacting or contacting the mixture with a compound which contains an alkali metal or an alkaline earth metal.
  
[List of Patents for class 423 subclass 85]    85Forming insoluble compound containing Group IVB metal
 This subclass is indented under subclass 69.  Processes in which a liquid or slurry is treated to form a substance containing a Group IVB metal and which substance is insoluble in, and comes out of solution from, the liquid or slurry, or the composition of the liquid is changed so that the part of the mixture containing the Group IVB metal becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid or slurry.
  
[List of Patents for class 423 subclass 86]    86Dissolving or leaching of iron
 This subclass is indented under subclass 69.  Processes which include the step of dissolving or leaching iron and thereby separating it from part of the original mixture; see Glossary.

SEE OR SEARCH THIS CLASS, SUBCLASS:

150.3,for general processes for chemically leaching iron values from iron-bearing ores.
  
[List of Patents for class 423 subclass 87]    87Group VA metal or arsenic (Sb, Bi, or As)
 This subclass is indented under subclass 1.  Processes in which the compound comprises antimony, bismuth or arsenic.
(1) Note. For purposes of this Class 423, arsenic is considered to be a metal.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing Sb, Bi, or As.
  
[List of Patents for class 423 subclass 88]    88Volatizing
 This subclass is indented under subclass 87.  Processes which include the step of causing a normally solid or liquid substance in either elemental or compound form to be changed into a gas or a vapor; see Glossary.
  
[List of Patents for class 423 subclass 89]    89Group IVA metal (Ge, Sn, or Pb)
 This subclass is indented under subclass 1.  Processes in which the compound comprises germanium, tin, or lead.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing Ge, Sn, or Pb
  
[List of Patents for class 423 subclass 90]    90Detinning
 This subclass is indented under subclass 89.  Processes in which the compound comprises tin and is obtained by treating an article or waste material of a mixture of metals which includes tin (e.g., terne plate, tin plate, cans, etc.).

SEE OR SEARCH CLASS:

134Cleaning and Liquid Contact With Solids,   subclasses 2+ for a process of treating articles or material for the purpose of cleaning or removing foreign matter therefrom, not to remove or strip a metal coating to recover the metal.
  
[List of Patents for class 423 subclass 91]    91Treating with free halogen or hydrogen halide
 This subclass is indented under subclass 90.  Processes in which the article or waste material is treated with a halogen which is either in the free state or combined with hydrogen as a halogen containing acid.
  
[List of Patents for class 423 subclass 92]    92Forming insoluble substance in liquid
 This subclass is indented under subclass 89.  Processes in which a liquid or slurry is treated to form a substance which is insoluble in and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 93]    93Pressurizing or agitating during reaction
 This subclass is indented under subclass 92.  Processes in which a chemical reaction takes place while the pressure on the mixture is higher than atmospheric or while the mixture is agitated or vibrated.
(1) Note. Agitation or vibration can be effected by any means, e.g., mechanical, sonic, fluid, etc. Pressure increase can be effected by any means, e.g., submerged blast of a gas into a liquid or slurry mixture, pumping of the liquid or slurry mixture, increase in pressure of the gas space above a liquid surface, etc.
  
[List of Patents for class 423 subclass 94]    94Halogenating
 This subclass is indented under subclass 92.  Processes which includes the step of chemically forming a compound containing a halogen.
  
[List of Patents for class 423 subclass 95]    95Nitrating or sulfating
 This subclass is indented under subclass 92.  Processes which include the step of chemically forming a compound which contains the nitrate (NO3-) radical or the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 96]    96Volatizing germanium or tin
 This subclass is indented under subclass 89.  Processes including the step of causing germanium or tin in elemental or compound form to be changed into a gas or vapor; see Glossary.
  
[List of Patents for class 423 subclass 97]    97Volatizing lead
 This subclass is indented under subclass 89.  Processes including the step of causing lead in elemental or compound form to be changed into a gas or vapor; see Glossary.
  
[List of Patents for class 423 subclass 98]    98Leaching, washing, or dissolving
 This subclass is indented under subclass 89.  Processes which include leaching, washing or dissolving out a portion of the mixture; see Glossary.

SEE OR SEARCH THIS CLASS, SUBCLASS:

90,for a process of destining scrap metal by forming and dissolving a tin compound.
  
[List of Patents for class 423 subclass 99]    99Group IIB metal (Zn, Cd, or Hg)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises zinc, cadmium or mercury.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 407 , 412 and 249-260 for the destruction or containment of hazardous or toxic waste containing Zn, Cd, or Hg.
  
[List of Patents for class 423 subclass 100]    100Ion exchanging or magnetic separating
 This subclass is indented under subclass 99.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance or (2) attracting and separating a component of the mixture from another component by means of magnetic lines of force; see Glossary.
  
[List of Patents for class 423 subclass 101]    101Forming insoluble substance in liquid
 This subclass is indented under subclass 99.  Processes wherein a liquid or a slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 102]    102Agitating during reaction
 This subclass is indented under subclass 101.  Processes in which a chemical reaction takes place while the mixture is agitated or vibrated.
(1) Note. Agitation or vibration can be effected by any means, e.g., mechanical, sonic, fluid, etc.
  
[List of Patents for class 423 subclass 103]    103Halogenating
 This subclass is indented under subclass 101.  Processes including the step of chemically forming a compound which contains a halogen.
  
[List of Patents for class 423 subclass 104]    104Hydroxylating or hydrating
 This subclass is indented under subclass 101.  Processes including the step of chemically forming a hydroxide or a hydrate.
  
[List of Patents for class 423 subclass 105]    105Carbonating
 This subclass is indented under subclass 101.  Processes including the step of chemically forming a compound having the carbonate (CO32-) radical.
  
[List of Patents for class 423 subclass 106]    106Sulfating
 This subclass is indented under subclass 101.  Processes including the step of chemically forming a compound having the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 107]    107Volatizing zinc, cadmium, or mercury
 This subclass is indented under subclass 99.  Processes including the step of causing zinc, cadmium or mercury in elemental or compound form to be changed into a gas or a vapor; see Glossary.
  
[List of Patents for class 423 subclass 108]    108Mixture contains lead
 This subclass is indented under subclass 107.  Processes wherein the mixture contains lead.
  
[List of Patents for class 423 subclass 109]    109Leaching, washing, or dissolving
 This subclass is indented under subclass 99.  Processes which include leaching, washing, or dissolving out a portion of the mixture; see Glossary.
  
[List of Patents for class 423 subclass 110]    110Desulfurizing
 This subclass is indented under subclass 99.  Processes including the step of removing at least some sulfur from the mixture.
  
[List of Patents for class 423 subclass 111]    111Group IIIA metal or beryllium (Al, Ga, In, Tl, or Be)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises beryllium, aluminum, gallium, indium or thallium.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing, Al, Ga, In, Tl, or Be.
  
[List of Patents for class 423 subclass 112]    112Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 111.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance or (2) selectively dissolving a component in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 113]    113Magnetic separating
 This subclass is indented under subclass 111.  Processes wherein a separation is made by attracting and separating a component of the mixture from another component by means of magnetic lines of force; see Glossary.
  
[List of Patents for class 423 subclass 114]    114Forming compound containing ammonium and metal
 This subclass is indented under subclass 111.  Processes including the step of chemically forming a compound which contains the ammonium radical and a metal.
  
[List of Patents for class 423 subclass 115]    115Forming compound containing plural metals
 This subclass is indented under subclass 111.  Processes including the step of chemically forming a compound which contains a plurality of metals.
  
[List of Patents for class 423 subclass 116]    116And halogen
 This subclass is indented under subclass 115.  Processes wherein the compound also contains a halogen.
  
[List of Patents for class 423 subclass 117]    117And sulfur
 This subclass is indented under subclass 115.  Processes wherein the compound also contains sulfur.
  
[List of Patents for class 423 subclass 118.1]    118.1Aluminosilicate other than zeolite:
 This subclass is indented under subclass 115.  Processes wherein the compound is an aluminosilicate, other than a zeolite, containing silicon, oxygen, aluminum, and another metal; e.g., sodium aluminosilicate.

SEE OR SEARCH THIS CLASS, SUBCLASS:

700+,for products and processes for producing zeolites.
  
[List of Patents for class 423 subclass 119]    119Alkali metal aluminate
 This subclass is indented under subclass 115.  Processes wherein the compound is an alkali metal aluminate, e.g., sodium aluminate (Na2Al204 or Na Al O2).
  
[List of Patents for class 423 subclass 120]    120From alunite
 This subclass is indented under subclass 119.  Processes wherein the mixture or source material includes the mineral alunite, which is naturally occurring K2SO4.Al2(SO4)3 4Al(OH)3 or KAl3(OH) 6(SO4)3.
  
[List of Patents for class 423 subclass 121]    121From bauxite
 This subclass is indented under subclass 119.  Processes wherein the mixture or source material is the mineral bauxite, which is naturally occurring Al2O(OH)4.
  
[List of Patents for class 423 subclass 122]    122Forming insoluble substance in liquid
 This subclass is indented under subclass 111.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 123]    123Subjecting mixture to pressure, vacuum, or steam
 This subclass is indented under subclass 122.  Processes wherein a chemical reaction takes place while the pressure on the mixture is either higher or lower than atmospheric; or while steam or water vapor is brought into contact with the mixture.
(1) Note. Pressure increase, or decrease can be effected by any means, e.g., submerged blast of a gas into a slurry or liquid, pumping of the liquid or slurry, increase or decrease in pressure of the gas space above a liquid surface, etc.
  
[List of Patents for class 423 subclass 124]    124Agitating during reaction
 This subclass is indented under subclass 122.  Processes wherein a chemical reaction takes place while the mixture is agitated or vibrated.
(1) Note. Agitation or vibration can be effected by any means, e.g., mechanical, sonic, fluid, etc.
  
[List of Patents for class 423 subclass 125]    125Nitrating
 This subclass is indented under subclass 122.  Processes including the step of chemically forming a compound having the nitrate (NO3-) radical.
  
[List of Patents for class 423 subclass 126]    126Halogenating
 This subclass is indented under subclass 122.  Processes which include the step of chemically forming a compound having a halogen as part thereof.
  
[List of Patents for class 423 subclass 127]    127Hydroxylating or hydrating
 This subclass is indented under subclass 122.  Processes including the step of chemically forming a hydroxide or a hydrate.
  
[List of Patents for class 423 subclass 128]    128Sulfating
 This subclass is indented under subclass 122.  Processes including the step of chemically forming a compound containing the sulfate (SO42-)radical.
  
[List of Patents for class 423 subclass 129]    129Carbonating
 This subclass is indented under subclass 122.  Processes including the step of chemically forming a compound having the carbonate (CO32-) radical.
  
[List of Patents for class 423 subclass 130]    130Destroying or separating organic impurity
 This subclass is indented under subclass 111.  Processes in which the mixture contains an impurity which meets the definitions of an organic compound and the process includes a step of (1) removing the impurity from the mixture or (2) doing away with or breaking up completely the impurity.
(1) Note. The organic impurity may be done away with or broken up completely by any means, as for example, chemical or flame oxidation, or combustion, etc.
  
[List of Patents for class 423 subclass 131]    131Leaching, washing, or dissolving
 This subclass is indented under subclass 111.  Processes which include leaching, washing, or dissolving out a portion of the mixture; see Glossary.
  
[List of Patents for class 423 subclass 132]    132With acid
 This subclass is indented under subclass 131.  Processes in which an acid is used as the leaching, washing or the solvent medium.
  
[List of Patents for class 423 subclass 133]    133Volatizing
 This subclass is indented under subclass 111.  Processes including the step of causing a normally solid or liquid substance in either element or compound form to be changed into a gas or a vapor; see Glossary.
  
[List of Patents for class 423 subclass 134]    134Beryllium
 This subclass is indented under subclass 133.  Processes in which the substance is beryllium.
  
[List of Patents for class 423 subclass 135]    135Group IIIA metal
 This subclass is indented under subclass 133.  Processes in which the substance is aluminum, gallium, indium or thallium.
  
[List of Patents for class 423 subclass 136]    136Utilizing elemental halogen as reactant
 This subclass is indented under subclass 135.  Processes which include the step of reacting an uncombined halogen.
  
[List of Patents for class 423 subclass 137]    137Utilizing carbon as reducing agent
 This subclass is indented under subclass 111.  Processes in which include the step of using elemental carbon as a reducing agent.
  
[List of Patents for class 423 subclass 138]    138Iron group metal (Fe, Co, or Ni)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises one of the three metals in Period 4, Group VIII of the periodic system, i.e., iron, cobalt or nickel, commonly known as the iron group metals; see Glossary.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclass 407 , 412 and 249-260 for the destruction or containment of hazardous or toxic waste containing Fe, Co, and Ni.
  
[List of Patents for class 423 subclass 139]    139Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 138.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance, or (2) selectively dissolving a component in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 140]    140Forming insoluble substance in liquid
 This subclass is indented under subclass 138.  Processes wherein a liquid or a slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 141]    141Subjecting mixture to pressure, vacuum, or steam
 This subclass is indented under subclass 140.  Processes wherein a chemical reaction takes place while the pressure on the mixture is either higher or lower than atmospheric; or while steam or water vapor is brought into contact with mixture.
(1) Note. Pressure increase or decrease can be effected by any means, e.g., submerged blast of a gas into a slurry or liquid, pumping of the liquid or slurry, increase or decrease in pressure of the gas space above a liquid surface, etc.
  
[List of Patents for class 423 subclass 142]    142Agitating during reaction
 This subclass is indented under subclass 140.  Processes wherein the mixture is agitated or vibrated while a chemical reaction is taking place.
(1) Note. Agitation or vibration can be effected by any means, e.g., mechanical, sonic, fluid, etc.
  
[List of Patents for class 423 subclass 143]    143Utilizing or forming nitrogenous compound
 This subclass is indented under subclass 140.  Processes wherein a nitrogen containing compound is formed, reacted, or placed in contact with the mixture during part of the process.
  
[List of Patents for class 423 subclass 144]    144Carbonating, hydroxylating, or hydrating
 This subclass is indented under subclass 143.  Processes including the step of chemically forming a hydroxide, or a hydrate, or a compound having the carbonate (CO32-) radical.
  
[List of Patents for class 423 subclass 145]    145Sulfating
 This subclass is indented under subclass 143.  Processes including the step of chemically forming a compound containing the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 146]    146Sulfating
 This subclass is indented under subclass 140.  Processes including the step of forming a compound containing the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 147]    147Halogenating, hydroxylating, or hydrating
 This subclass is indented under subclass 146.  Processes including the step of chemically forming a hydroxide, or a hydrate or a compound containing a halogen element.
  
[List of Patents for class 423 subclass 148]    148Utilizing fluidized bed
 This subclass is indented under subclass 138.  Processes in which solids are suspended in upward flowing gas or vapor, the upward force of the fluid on the solids is countered by gravity resulting in the formation of a zone in which the particles are compacted into a dense phase; see Glossary.
(1) Note. The particles are in a state of hindered settling and the dense bed resembles a boiling liquid and above this dense bed some solids may be suspended in a dilute or dispersed phase.
  
[List of Patents for class 423 subclass 149]    149Volatizing iron, nickel, or cobalt
 This subclass is indented under subclass 138.  Processes including the step of causing any of the iron group metals either as an element or a compound to be changed into a gas or a vapor; see Glossary.
  
[List of Patents for class 423 subclass 150.1]    150.1Leaching, washing, or dissolving:
 This subclass is indented under subclass 138.  Processes which include removing or bringing into solution matter by leaching, washing, or dissolving out a portion of the mixture - see glossary.

SEE OR SEARCH THIS CLASS, SUBCLASS:

140+,for leaching processes which further include a step of forming an insoluble substance in a liquid.
  
[List of Patents for class 423 subclass 150.2]    150.2Spent catalyst:
 This subclass is indented under subclass 150.1.  Processes that include recovering values from catalysts.

SEE OR SEARCH CLASS:

502Catalyst, Solid Sorbent, or Support Therefor: Product or Process of Making,   subclasses 22+ for processes of treating in a liquid phase to regenerate or rehabilitate a catalyst.
  
[List of Patents for class 423 subclass 150.3]    150.3Treatment of iron containing waste mixture:
 This subclass is indented under subclass 150.1.  Processes which include treatment of iron containing product stream that is a by-product or discarded product of another process (e.g., products of pickle liquor).

SEE OR SEARCH THIS CLASS, SUBCLASS:

531,for removal or separation of impurities present in sulfuric acid or reactants that form sulfuric acid.

SEE OR SEARCH CLASS:

208Mineral Oils: Processes and Products,   subclass 13 for treatment of mineral oil refining sludge.
216Etching a Substrate: Processes,   particularly subclass 93 for methods of chemical etching including a step of recycling the etchant.
  
[List of Patents for class 423 subclass 150.4]    150.4Treatment of matte or nodule:
 This subclass is indented under subclass 150.1.  Processes in which the mixture is a matte or nodule containing material (i.e., in form of roasted or smelted ore) or relatively small lumps of mineral.
  
[List of Patents for class 423 subclass 150.5]    150.5Gas injected into mixture:
 This subclass is indented under subclass 150.4.  Processes which include a step of injecting matter that is gaseous at ambient temperature into the mixture.
  
[List of Patents for class 423 subclass 150.6]    150.6With electrolytic or magnetic separation:
 This subclass is indented under subclass 150.1.  Process which include a step of removing a component from the mixture by electric current or magnetomotive force.

SEE OR SEARCH CLASS:

205Electrolysis: Processes, Compositions Used Therein, and Methods of Preparing the Compositions,   appropriate subclasses for electrolytic processes.
209Classifying, Separating, and Assorting Solids,   appropriate subclasses for processes of separating a mixture by magnetic action without a chemical reaction.
210Liquid Purification or Separation,   subclasses 222+ for processes of separation in liquids by magnetic attraction.
  
[List of Patents for class 423 subclass 151]    151Converting metal to magnetic form
 This subclass is indented under subclass 138.  Processes including the step of changing a metal from a nonmagnetic to a magnetic form.
(1) Note. Although many patents in this subclass are drawn to "magnetic roasting", i.e., roasting of Fe2°3 to form magnetic Fe3°4 (FeO. Fe2°3) other forms of conversion from nonmagnetic to magnetic forms may also be found.
(2) Note. Magnetic separation may also be included in the processes classified in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

148,for similar processes wherein a fluidized bed is utilized.
632+,for patents wherein Fe3O4 is made from a relatively pure starting material.

SEE OR SEARCH CLASS:

209Classifying, Separating, and Assorting Solids,   appropriate subclasses, especially subclasses 38 through 40and 212-232, for processes and apparatus for magnetic separating of materials, including ores, where no chemical change takes place.
  
[List of Patents for class 423 subclass 152]    152At specified temperature
 This subclass is indented under subclass 151.  Processes wherein the temperature or range thereof at which the conversion is made is recited specifically.
  
[List of Patents for class 423 subclass 153]    153Desulfurizing
 This subclass is indented under subclass 138.  Processes including the step of removing at least some sulfur from the mixture.
  
[List of Patents for class 423 subclass 154]    154At specified temperature
 This subclass is indented under subclass 153.  Processes wherein the temperature or range thereof at which the sulfur removal takes place is specifically recited.
  
[List of Patents for class 423 subclass 155]    155Alkaline earth metal (Mg, Ca, Sr, or Ba)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises one of the metals belonging to the group known as the alkaline earth metals, i.e., magnesium, calcium, strontium or barium, or the Group 11A metals of the periodic system except for beryllium and radium.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2+,for a process of obtaining a radium compound from a mixture.
111+,for a process of obtaining a beryllium compound from a mixture.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing Mg, Ca, Sr, or Ba.
  
[List of Patents for class 423 subclass 156]    156Magnetic separating
 This subclass is indented under subclass 155.  Processes which include the step of attracting a component or portion of the mixture by means of magnetic lines of force to effect a separation.
  
[List of Patents for class 423 subclass 157]    157Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 155.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance or (2) selectively dissolving a component in one of two immiscible liquids to effect a separation; see Glossary.
  
[List of Patents for class 423 subclass 157.2]    157.2Phosphate rock or ore:
 This subclass is indented under subclass 155.  Processes wherein the initial mixture is a naturally formed aggregate material of earth in the form of rock or ore containing phosphate.
  
[List of Patents for class 423 subclass 157.3]    157.3Acid treatment:
 This subclass is indented under subclass 157.2.  Processes wherein the mixture is treated with an acid.
  
[List of Patents for class 423 subclass 157.4]    157.4Sulfating:
 This subclass is indented under subclass 157.3.  Processes in which the treatment includes the step of chemically forming a compound containing the sulfate, (SO4)-2, radical.
(1) Note. Included in this subclass are treatments with materials such as sulfuric acid and (SO4)-2 salts.
  
[List of Patents for class 423 subclass 157.5]    157.5Phosphorous or phosphorous compound containing waste as feed:
 This subclass is indented under subclass 155.  Processes wherein the mixture treated is a by-product or discarded product of another process.
  
[List of Patents for class 423 subclass 158]    158Forming insoluble substance in liquid
 This subclass is indented under subclass 155.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Cystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 159]    159Subjecting mixture to pressure, vacuum, or steam
 This subclass is indented under subclass 158.  Processes wherein a chemical reaction takes place while the pressure on the mixture is either higher or lower than atmospheric; or while steam or water vapor is brought into contact with the mixture.
(1) Note. Pressure increase or decrease can be effected by any means, e.g., submerged blast of a gas into a liquid or a slurry, pumping of the liquid or slurry, increase or decrease on pressure of the gas space above a liquid surface.
  
[List of Patents for class 423 subclass 160]    160Agitating during reaction
 This subclass is indented under subclass 158.  Processes wherein the mixture is agitated or vibrated while a chemical reaction is taking place.
(1) Note. Agitation or vibration can be effected by any means, e.g., fluid, mechanical or sonic, etc.
  
[List of Patents for class 423 subclass 161]    161Specified particle size used or made
 This subclass is indented under subclass 158.  Processes in which a specific particle size is either employed or formed.
(1) Note. The particle size may be specified in any way, e.g., mesh size, dimension, etc., and may be formed or employed in any process step prior, during or subsequent, to a chemical reaction.
  
[List of Patents for class 423 subclass 162]    162Nitrating or ammoniating
 This subclass is indented under subclass 158.  Processes including the step of chemically forming a compound which contains the nitrate (NO3-) radical or the ammonium (NH4+) radical.
  
[List of Patents for class 423 subclass 163]    163Halogenating
 This subclass is indented under subclass 158.  Processes including the step of chemically forming a compound containing a halogen.
  
[List of Patents for class 423 subclass 164]    164Hydroxylating or hydrating
 This subclass is indented under subclass 158.  Processes including the step of chemically forming a hydroxide or a hydrate.
  
[List of Patents for class 423 subclass 165]    165Carbonating
 This subclass is indented under subclass 158.  Processes including the step of chemically forming a compound having the carbonate (CO32-) radical.
  
[List of Patents for class 423 subclass 166]    166Sulfating
 This subclass is indented under subclass 158.  Processes including the step of chemically forming a compound having the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 167.1]    167.1Treating asbestos:
 This subclass is indented under subclass 155.  Processes wherein the mixture treated has asbestos, a native magnesium calcium silicate (e.g., chrysotile, crocidolite and amosite).

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclass 411 for the chemical destruction of asbestos, and subclass 154 for the permanent containment of asbestos.
  
[List of Patents for class 423 subclass 168]    168Mixing fuel with starting mixture
 This subclass is indented under subclass 155.  Processes wherein a combustible fuel material is mixed with the raw or original mixture.
  
[List of Patents for class 423 subclass 169]    169Separating magnesium and calcium from each other (e.g., treating dolomite, etc.)
 This subclass is indented under subclass 155.  Processes wherein the original mixture includes magnesium and calcium and wherein each is separated from the other.

SEE OR SEARCH THIS CLASS, SUBCLASS:

158+,for processes of separating magnesium and calcium from each other by forming an insoluble substance in a liquid.
  
[List of Patents for class 423 subclass 170]    170Treating impure sulfate (e.g., barite, etc.)
 This subclass is indented under subclass 155.  Processes in which the original mixture contains a metal sulfate.
  
[List of Patents for class 423 subclass 171]    171Calcining gypsum
 This subclass is indented under subclass 170.  Processes wherein at least some of the water of hydration is removed from gypsum (CaSO4 2H2O) by applying heat.
(1) Note. Usually gypsum or calcium sulfate dehydrate (Ca SO4.2H2O) is calcined to obtain plaster of Paris or calcium sulfate hemihydrate (CaSO4.1/2H2O).
  
[List of Patents for class 423 subclass 172]    172With steam or at specified temperature
 This subclass is indented under subclass 171.  Processes in which the heat for removing the water of hydration is supplied by steam or water vapor, or the particular heating temperature, or range thereof, is specified.
  
[List of Patents for class 423 subclass 173]    173Treating impure carbonate (e.g., oyster shells, etc.)
 This subclass is indented under subclass 155.  Processes wherein the original mixture contains the carbonate of an alkaline earth metal.
(1) Note. Limestone, magnetite, oyster shells, etc., are assumed to be impure since they are naturally occurring carbonates. Patents which claim treating calcium carbonate which is disclosed as being limestone, for example, are classified here. Processes for treating dolomite or oyster shells are classified here when no separation of the calcium and magnesium from each other is made.

SEE OR SEARCH THIS CLASS, SUBCLASS:

169,for treating impure carbonates, such as dolomite, to separate magnesium and calcium from each other, and subclass 167, for treating phosphate rock which contains some calcium carbonate.
  
[List of Patents for class 423 subclass 174]    174Forming calcium carbide
 This subclass is indented under subclass 173.  Processes including the step of chemically forming calcium carbide (CaC2).
  
[List of Patents for class 423 subclass 175]    175Calcining
 This subclass is indented under subclass 173.  Processes which include the step of heating the impure carbonate.
(1) Note. The end result of calcining an impure carbonate is usually the oxide due to driving off the carbon dioxide (CO2).
  
[List of Patents for class 423 subclass 176]    176Utilizing vacuum or steam
 This subclass is indented under subclass 175.  Processes wherein the mixture is subjected to a pressure below atmospheric or the heat is supplied by steam or water vapor.
  
[List of Patents for class 423 subclass 177]    177With agitating or at specified temperature
 This subclass is indented under subclass 175.  Processes including the step of agitating or vibrating the mixture while it is being heated or in which a particular heating temperature or range thereof is specified.
  
[List of Patents for class 423 subclass 178]    178Mixture contains halogen or sulfur
 This subclass is indented under subclass 155.  Processes wherein the original mixture contains a halogen or sulfur.
  
[List of Patents for class 423 subclass 179]    179Alkali metal (Li, Na, K, Rb, or Cs)
 This subclass is indented under subclass 1.  Processes wherein the compound comprises one of the metals belonging to the group known as the alkali metals, i.e., lithium, sodium, potassium, rubidium or cesium or the metals of Group 1A of the periodic system except for francium.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste being volatilized and containing Li, Na, K, Rb, and Cs.
  
[List of Patents for class 423 subclass 179.5]    179.5Lithium:
 This subclass is indented under subclass 179.  Processes wherein the metal has atomic number 3.
  
[List of Patents for class 423 subclass 180]    180Decomposing amalgam or other alloy
 This subclass is indented under subclass 179.  Processes wherein the mixture is an amalgam or another alloy of two or more metals.
(1) Note. Amalgams and alloys are considered mixtures for the purposes of this class.
  
[List of Patents for class 423 subclass 181]    181Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 179.  Processes which include the step of (1) attracting and retaining a component of the mixture by contact with an ion exchange substance or (2) selectively dissolving a component in one of two immiscible liquids to effect a separations; see Glossary.
  
[List of Patents for class 423 subclass 182]    182Regenerating solution
 This subclass is indented under subclass 179.  Processes in which the alkali metal is contained in a solution used in a process, and has become ineffective to properly function in such a process because of dilution, impurities or other reason, and the solution is then regenerated or rehabilitated to approximately its original state or condition.
(1) Note. The purpose of the processes classified here is merely regeneration. A process for another purpose which includes the subcombination of regenerating a solution is classified with the more comprehensive process. The solutions treated here are generally those used to react with an organic substance such as wood pulp and petroleum.
  
[List of Patents for class 423 subclass 183]    183Hydroxide solution
 This subclass is indented under subclass 182.  Processes wherein the solution contains hydroxide (OH-) ions.
  
[List of Patents for class 423 subclass 184]    184Forming insoluble substance in liquid
 This subclass is indented under subclass 179.  Processes wherein a liquid or slurry is treated to form a substance which is insoluble therein and comes out of solution, or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein, so the insoluble substance can be separated from the liquid and the materials which remain soluble in the liquid.
(1) Note. Crystallization of a substance is included under this definition of insolubilization.
  
[List of Patents for class 423 subclass 185]    185Fluorinating or defluorinating
 This subclass is indented under subclass 184.  Processes including the step of (1) chemically forming a compound having fluorine therein, (2) using fluorine in any form as a reactant or (3) treating the mixture to remove fluorine therefrom.
  
[List of Patents for class 423 subclass 186]    186Carbonating
 This subclass is indented under subclass 184.  Processes including the step of chemically forming a compound having the carbonate (CO32-) radical.
  
[List of Patents for class 423 subclass 187]    187Utilizing or forming nitrogenous compound
 This subclass is indented under subclass 186.  Processes wherein a compound containing nitrogen is formed, is reacted or is in contact with the mixture during at least part of the process.
  
[List of Patents for class 423 subclass 188]    188Subjecting mixture to pressure, vacuum, or steam
 This subclass is indented under subclass 186.  Processes wherein a reaction takes place while the pressure on the mixture is either higher or lower than atmospheric, or wherein steam or water vapor is brought into contact with the mixture.
(1) Note. Pressure increase or decrease can be effected by any means; e.g., submerged blast of a gas into a liquid or a slurry, pumping of the liquid or slurry, increase or decrease in pressure of the gas space above a liquid surface, etc.
  
[List of Patents for class 423 subclass 189]    189Utilizing carbon dioxide as reactant
 This subclass is indented under subclass 186.  Processes including the step of reacting carbon dioxide (CO2) with at least part of the mixture.
  
[List of Patents for class 423 subclass 190]    190Mixture contains metal chloride
 This subclass is indented under subclass 189.  Processes wherein the original mixture contains a metallic chloride compound.
  
[List of Patents for class 423 subclass 191]    191Halogenating
 This subclass is indented under subclass 186.  Processes including the step of chemically forming a compound containing a halogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

185,for similar processes wherein the halogen is fluorine.
  
[List of Patents for class 423 subclass 192]    192Hydroxylating or hydrating
 This subclass is indented under subclass 186.  Processes including the step of chemically forming a hydroxide or a hydrate.
  
[List of Patents for class 423 subclass 193]    193Sulfating
 This subclass is indented under subclass 186.  Processes including the step of chemically forming a compound containing the sulfate (SO42-) radical.
  
[List of Patents for class 423 subclass 194]    194Utilizing or forming nitrogenous compound
 This subclass is indented under subclass 184.  Processes wherein a compound containing nitrogen is formed, is reacted, or is in contact with the mixture during at least part of the process.

SEE OR SEARCH THIS CLASS, SUBCLASS:

187,above for similar processes including carbonation.
  
[List of Patents for class 423 subclass 195]    195Subjecting mixture to pressure, vacuum, or steam
 This subclass is indented under subclass 184.  Processes wherein a reaction takes place while the pressure on the mixture is either higher or lower than atmospheric; or wherein steam or water vapor is brought in contact with the mixture.
(1) Note. Pressure increase or decrease can be be effected by any means, e.g., submerged blast of a gas into a liquid or a slurry, pumping of the liquid or slurry, increase or decrease in pressure of the gas space above a liquid surface, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:

188,above for similar processes which include carbonation.
  
[List of Patents for class 423 subclass 196]    196Agitating during reaction
 This subclass is indented under subclass 184.  Processes in which a chemical reaction takes place while the mixture is agitated or vibrated.
(1) Note. Agitation or vibration can be effected by any means, e.g., fluid, mechanical or sonic etc.
  
[List of Patents for class 423 subclass 197]    197Halogenating
 This subclass is indented under subclass 184.  Processes including the step of chemically forming a compound containing a halogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

185,above for similar processes wherein the halogen is fluorine and subclass 191 for similar processes which include carbonation.
  
[List of Patents for class 423 subclass 198]    198Hydroxylating or hydrating
 This subclass is indented under subclass 184.  Processes including the step of chemically forming a hydroxide or a hydrate.

SEE OR SEARCH THIS CLASS, SUBCLASS:

192,for similar processes which include carbonation.
  
[List of Patents for class 423 subclass 199]    199Sulfating
 This subclass is indented under subclass 184.  Processes including the step of chemically forming a compound having the sulfate radical (SO42-).
  
[List of Patents for class 423 subclass 200]    200Volatizing an alkali metal
 This subclass is indented under subclass 179.  Processes including the step of causing an alkali metal in either the element or compound form to pass into a vapor; see Glossary.
  
[List of Patents for class 423 subclass 201]    201Agitating during heating or reaction
 This subclass is indented under subclass 179.  Processes wherein the mixture is agitated or vibrated while being heated or while a reaction is occurring.
(1) Note. Agitation or vibration may be effected by any means, e.g., fluid, mechanical or sonic, etc.
  
[List of Patents for class 423 subclass 202]    202Treating with acid or acid salt
 This subclass is indented under subclass 179.  Processes including the step of using a compound which yields hydrogen (H+) ions in solution and gives a pH of below 7, such as an acid or acid salt, e.g., NaHSO4, etc.
  
[List of Patents for class 423 subclass 203]    203Subjecting mixture to pressure, vacuum, or steam
 This subclass is indented under subclass 179.  Processes wherein the reaction or heating takes place while the pressure on the mixture is either higher or lower than atmospheric, or wherein steam or water vapor is brought in contact with the mixture.
(1) Note. Pressure increase or decrease can be effected by any means, e.g., submerged blast of a gas into a liquid or slurry, pumping of the liquid or slurry, increase or decrease in pressure of the gas space above a liquid surface, etc.
  
[List of Patents for class 423 subclass 204]    204Mixture contains organic impurity
 This subclass is indented under subclass 203.  Processes wherein the original mixture contains an organic impurity.

SEE OR SEARCH THIS CLASS, SUBCLASS:

182+,for a process which includes a step of regenerating or rehabilitating a solution, usually containing an organic impurity to obtain or recover alkali metal.
  
[List of Patents for class 423 subclass 205]    205Leaching or forming water soluble substance
 This subclass is indented under subclass 203.  Processes including the step of dissolving out part of a solid, or chemically forming a substance while is soluble in water; see Glossary for leaching.

SEE OR SEARCH THIS CLASS, SUBCLASS:

202,for processes which include the step of leaching with an acidic substance.
  
[List of Patents for class 423 subclass 206.1]    206.1Mixture contains organic or carbonaceous impurity:
 This subclass is indented under subclass 179.  Processes wherein the original mixture has an organic or a carbon containing impurity.

SEE OR SEARCH THIS CLASS, SUBCLASS:

182+,for processes which include regeneration of an alkali metal containing solution which also contains an organic impurity.

SEE OR SEARCH CLASS:

162Paper Making and Fiber Liberation,   subclass 30.11 for processes intended to treat paper making liquor.
  
[List of Patents for class 423 subclass 206.2]    206.2Alkali carbonate from trona:
 This subclass is indented under subclass 206.1.  Processes wherein the original mixture contains trona; i.e., an ore characterized by containing sodium carbonate.
  
[List of Patents for class 423 subclass 207]    207Burning the impurity
 This subclass is indented under subclass 206.1.  Processes including combusting the organic or carbonaceous impurity.
  
[List of Patents for class 423 subclass 208]    208Water leaching or forming water soluble substance
 This subclass is indented under subclass 179.  Processes including the step of dissolving out a portion of a solid with water as a solvent, or forming a substance which is soluble in water; see Glossary for leaching.

SEE OR SEARCH THIS CLASS, SUBCLASS:

179,for processes which include the step of leaching with water containing other materials, e.g., brine etc.
202,for processes which include the step of leaching with an acidic substance.
205,for processes which include leaching or forming a water soluble substance and additionally employ pressure, vacuum, or steam.
  
[List of Patents for class 423 subclass 209]    209Carbonating
 This subclass is indented under subclass 179.  Processes including the step of chemically forming a compound having the carbonate (CO32-) radical.
  
[List of Patents for class 423 subclass 210]    210MODIFYING OR REMOVING COMPONENT OF NORMALLY GASEOUS MIXTURE
 This subclass is indented under the class definition.  Processes in which an initial gaseous or vaporous mixture is treated so as to remove therefrom or change to a different chemical form at least one of the components therein, resulting in a heterogeneous composition.
(1) Note. As between coordinate subclasses distinguished by specified chemical components, the original placement of a patent is in the first appearing subclass providing for a component which has been chemically modified.
(2) Note. A chemical reaction must be involved in the process.
(3) Note. Wherever the recovery of a definite chemical compound or element as a product is claimed, original classification of the patent is in the subclass following subclass 215.5 which provides for the compound or element. However, where the claim does not include the step of separating the modified component, the patent is classified here (subclasses 210+) even though disclosed intent is to ultimately effect separation of the component.
(4) Note. The mixture need not be entirely gaseous; it may contain entrained solids or liquids. It must however be handled and distributed as a gas and must be in this form at the onset of the treatment.

SEE OR SEARCH THIS CLASS, SUBCLASS:

264,for rendering an impurity ineffective in a process in which either the starting mixture is not gaseous, or if gaseous, the intent is to make a compound; see preceding notes.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   appropriate subclasses, for processes of purifying a gaseous mixture or separating a constituent therefrom where no chemical reaction is involved in the separation or purification, per se. In this respect sorption on a solid (e.g., silica gel, charcoal etc.) or in water even of gases such as NH3,SO3, etc. which may form alkalis or acids with the water is considered to be a nonchemical separation proper for Class 95. However, adsorption on a basic or acidic solid, or absorption in acid or a base is considered to be a chemical reaction and proper for Class 423, subclasses 210+ , unless the acid or base is the solvent for itself, i.e., hydrochloric acid for gaseous hydrogen chloride, sulfuric acid for sulfur trioxide, etc.
102Ammunition and Explosive,   subclass 23 , for blasting methods which include procedures for fume control.
149Explosive and Thermic Compositions or Charges,   subclass 108.4 for subject matter of that class drawn to control of the smoke or gas produced.
260Chemistry of Carbon Compounds,   appropriate subclasses for preparation and treatment of organic materials.
431Combustion,   for processes of burning exhaust gases where the intent is to use the gas as a fuel primarily and not to separate or purify the gas. Note subclass 224 in Class 423 where combustion is used to purify or separate a gas.
588Hazardous or Toxic Waste Destruction or Containment,   subclass 401 for the chemical destruction of chemical warfare agents, which may be gaseous. This class, 423, provides for the treatment or chemical destruction of hazardous or toxic gasses in general.
  
[List of Patents for class 423 subclass 210.5]    210.5Direct contact with molten material
 This subclass is indented under subclass 210.  Processes in which the treatment includes the direct contact between the gaseous mixture and a material in the molten state.
(1) Note. Molten material for this defines only those substance, which are solid at ambient conditions but have been rendered liquid by a change in conditions.
  
[List of Patents for class 423 subclass 212]    212Mixture is exhaust from internal-combustion engine
 This subclass is indented under subclass 210.  Processes in which the initial gaseous mixture is the exhaust from an internal combustion engine.

SEE OR SEARCH CLASS:

60Power Plants,   subclasses 272 through 308for exhaust gas treatment in cooperation with engine function.
422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 168+ for apparatus for purifying exhaust gases from an internal combustion engine in which apparatus a catalyst is employed.
  
[List of Patents for class 423 subclass 213.2]    213.2Utilizing as solid sorbent, catalyst, or reactant a material containing a transition element
 This subclass is indented under subclass 212.  Processes, in which the material used to treat the gaseous mixture is in the solid-state and comprises a transition element, or compound thereof, and which functions to (1) modify a component, or (2) attract and retain a component, or (3) react with and chemically change a component.
(1) Note. The transition elements are those having atomic numbers of 21 through 30, 39 through 48, 57 through 80, 89 through 103.

SEE OR SEARCH THIS CLASS, SUBCLASS:

212,for a process of treating the gaseous which the treating material, if a solid catalyst, sorbent or reactant, does not contain a transition element.
  
[List of Patents for class 423 subclass 213.5]    213.5Group VIII element
 This subclass is indented under subclass 213.2.  Processes in which the transition element is one which appears in Group VIII of the Periodic Table.
  
[List of Patents for class 423 subclass 213.7]    213.7Including successive stage treatments to modify or remove a different component in each stage
 This subclass is indented under subclass 213.2.  Processes in which there are at least two serial treatments of the gaseous mixture, each treatment modifying or removing a component different than that affected by the other.
  
[List of Patents for class 423 subclass 215.5]    215.5Solid component
 This subclass is indented under subclass 210.  Processes in which the component removed is in the solid-state in the gaseous mixture.
(1) Note. The solid component is usually particulate in form and may be foreign matter (e.g., dust), or a chemical element or compound.
(2) Note. The usual method of removing a solid component from a gas stream is by physical means, e.g., filtering, washing, deflecting, electrostatic precipitating, etc. However, a chemical reaction is required with the solid component for placement of a patent in this Class 423; see search note following for separating a gaseous mixture by physical means only.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   appropriate subclasses, for separating a gas mixture by mere physical means, e.g., filtering, deflecting, electrostatic precipitating, washing with liquid, etc. where no chemical reaction is involved.
  
[List of Patents for class 423 subclass 219]    219Molecular oxygen or ozone component:
 This subclass is indented under subclass 210.  Processes in which the component is oxygen in a molecular form or ozone.

SEE OR SEARCH THIS CLASS, SUBCLASS:

210,for processes for removing ozone from a gaseous mixture.
217+,for processes for removing molecular oxygen from atmospheric air.
  
[List of Patents for class 423 subclass 220]    220Carbon dioxide or hydrogen sulfide component
 This subclass is indented under subclass 210.  Processes wherein the component is carbon dioxide (CO2) or hydrogen sulfide (H2S).

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating carbon dioxide (CO2) or hydrogen sulfide (H2S) from a gaseous fluid mixture by physical means only. See particularly subclasses 43+ for selective diffusion of gases, subclasses 90+ for solid sorption, and subclasses 149+ for liquid contacting.
  
[List of Patents for class 423 subclass 221]    221Utilizing thionate or thiosulfate as reactant
 This subclass is indented under subclass 220.  Processes in which the material used to treat the gaseous mixture comprises a thionate or thiosulfate compound (S2O32-).
  
[List of Patents for class 423 subclass 222]    222Reacting mixture with sulfur dioxide, sulfite, or bisulfite
 This subclass is indented under subclass 220.  Processes in which the material used to treat the gaseous mixture comprises sulfur dioxide or a solution thereof or a sulfite (SO32-) or bisulfite (HSO3-) compound.

SEE OR SEARCH THIS CLASS, SUBCLASS:

574+,for processes including the step of reacting hydrogen sulfide with sulfur dioxide.
  
[List of Patents for class 423 subclass 223]    223Utilizing reactant containing arsenic, phosphorus, or boron
 This subclass is indented under subclass 220.  Processes in which the material used to treat the gaseous mixture comprises arsenic, phosphorus or boron or compounds thereof.
(1) Note. Catalysts containing arsenic, boron or phosphorus are not included under this definition of reactant.

SEE OR SEARCH THIS CLASS, SUBCLASS:

230+,for a process in which the gaseous mixture is treated with a catalyst or sorbent which may contain arsenic, phosphorous or boron.
  
[List of Patents for class 423 subclass 224]    224By oxidizing or burning component
 This subclass is indented under subclass 220.  Processes in which the component is removed or changed by causing (1) it to combine with oxygen, or to produce a flame, or (2) the augmentation of the valence number of an ion or atom thereof as the result of the loss of negative charges as electrons thereby making it more electropositive.
(1) Note. Excluded from this subclass is a process in which a sorbent containing the removed constituent is revivified or regenerated by treating with an oxidizing gas. For such a step, see subclasses 221, 222, or 233.

SEE OR SEARCH CLASS:

431Combustion,   subclasses 2+ for processes of burning a gas for use as a fuel.
  
[List of Patents for class 423 subclass 225]    225By suspension of metal oxide or hydroxide particles in liquid
 This subclass is indented under subclass 220.  Processes in which the material used to treat the gaseous mixture comprises solid particles of an oxide or hydroxide of a metal dispersed throughout a liquid vehicle.
  
[List of Patents for class 423 subclass 226]    226Utilizing organic reactant
 This subclass is indented under subclass 220.  Processes in which the material used to treat the gaseous mixture comprises an organic compound, at least in part.
(1) Note. An organic compound under this definition is as defined in the definition of Class 260, Chemistry of Carbon Compounds, as qualified by (34) Note therein.
(2) Note. The organic part may be present as the organic radical part of a compound or as the organic portion of a mixture of organic and inorganic materials.
  
[List of Patents for class 423 subclass 227]    227Phenolate or phenolic type
 This subclass is indented under subclass 226.  Processes wherein the compound has an aromatic nucleus in which at least one of the hydrogen atoms has been replaced by a hydroxyl group.
  
[List of Patents for class 423 subclass 228]    228Amine
 This subclass is indented under subclass 226.  Processes wherein the organic compound is one derived from ammonia by substituting an organic radical for at least one of the hydrogens.
  
[List of Patents for class 423 subclass 229]    229Ethanolamine
 This subclass is indented under subclass 228.  Processes in which an aminoalcohol substituent is ethanol.
  
[List of Patents for class 423 subclass 230]    230Utilizing solid sorbent, catalyst, or reactant
 This subclass is indented under subclass 220.  Processes in which the treating material is in the solid-state and functions to (1) modify a component, (2) attract and retain the component, or (3) react with and chemically change the constituent.

SEE OR SEARCH THIS CLASS, SUBCLASS:

223,for a process in which the reactant contains arsenic, phosphorus or boron and may be in the solid-state.
225,for a process in which the solid sorbent, reactant or catalyst is used in the form of a suspension in a liquid in the process.
  
[List of Patents for class 423 subclass 231]    231Iron oxide or hydroxide
 This subclass is indented under subclass 230.  Processes in which the solid treating material includes an oxide or hydroxide of iron.
  
[List of Patents for class 423 subclass 232]    232Utilizing carbonate as reactant
 This subclass is indented under subclass 220.  Processes in which the treating material comprises a carbonate (CO32-) or bicarbonate (HCO3-) compound in solution.
  
[List of Patents for class 423 subclass 233]    233And regenerating reactant by incoming actifying gas
 This subclass is indented under subclass 232.  Processes in which the material is revivified after being used by being contacted with a gas to cause the constituent to be separated or removed therefrom so that the material may again be used to treat the gaseous mixture.
  
[List of Patents for class 423 subclass 234]    234Utilizing ammonium or metal hydroxide solution
 This subclass is indented under subclass 220.  Processes in which the gaseous mixture in contacted with a treating material comprising the hydroxide of a metal or of ammonium, is solution.
  
[List of Patents for class 423 subclass 235]    235Nitrogen or nitrogenous component
 This subclass is indented under subclass 210.  Processes in which the component is molecular nitrogen or a nitrogen-containing compound.

SEE OR SEARCH THIS CLASS, SUBCLASS:

217,for a process of removing molecular nitrogen from atmospheric air.
  
[List of Patents for class 423 subclass 236]    236Component also contains carbon (e.g., cyanogen, hydrogen cyanide, etc.)
 This subclass is indented under subclass 235.  Processes in which the component is a compound containing nitrogen and carbon atoms.
(1) Note. Examples of such carbon containing nitrogen compounds are cyanogen chloride or hydrocyanic acid.
  
[List of Patents for class 423 subclass 237]    237Ammonia
 This subclass is indented under subclass 235.  Processes in which the component is ammonia (NH3).

SEE OR SEARCH THIS CLASS, SUBCLASS:

236,for processes of separating ammonia from a gas mixture which also includes a carbon containing nitrogen compound (e.g., a mixture of ammonia and hydrogen cyanide).

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating ammonia from a gaseous fluid mixture by physical means only. See particularly subclasses 43+ for selective diffusion of gases, subclasses 90+ for solid sorption, and subclasses 149+ for liquid contacting.
  
[List of Patents for class 423 subclass 238]    238Utilizing liquid as reactant
 This subclass is indented under subclass 237.  Processes in which the ammonia is removed or changed by means of a reactant in the liquid state.

SEE OR SEARCH THIS CLASS, SUBCLASS:

279through 282, 286-288, 305-315, 352-363, 396, 420, 470, 471, 517, 545-550, and 593.1-594.16, for processes of preparing an ammonium compound from a gas where it is clear that the main intent is to use the gas as the feedstock source of the ammonia and not to purify the gas.
  
[List of Patents for class 423 subclass 239.1]    239.1Utilizing solid sorbent, catalyst, or reactant:
 This subclass is indented under subclass 235.  Process in which the treating material is a solid and functions to (a) modify a component, (b) attract and retain a component, or (c) react with and chemically change a component.

SEE OR SEARCH THIS CLASS, SUBCLASS:

212,for processes which remove nitrogenous components from internal engine exhaust.
230,for processes using a solid sorbent, catalyst, or reactant to separate carbon dioxide or hydrogen sulfide in a gaseous mixture.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating nitrogen (N2) or nitrogen containing compounds from a gaseous fluid mixture by physical means only; particularly, subclasses 90+ for solid sorption, per se.
  
[List of Patents for class 423 subclass 239.2]    239.2Zeolite:
 This subclass is indented under subclass 239.1.  Process in which the treating material contains a zeolite.
  
[List of Patents for class 423 subclass 240]    240Halogenous component
 This subclass is indented under subclass 210.  Processes in which the component is a halogen containing material.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating a halogen from a gaseous fluid mixture by physical means only. See particularly subclasses 43+ for selective diffusion of gases, subclasses 90+ for solid sorption, and subclasses 149+ for liquid contacting.
  
[List of Patents for class 423 subclass 241]    241Free halogen
 This subclass is indented under subclass 240.  Processes in which the component is free or molecular halogen.
(1) Note. The constituent must be initially present in the gaseous mixture in the free or molecular form may be removed as such, or may be combined prior to removal or discharge.
  
[List of Patents for class 423 subclass 242.1]    242.1Sulfur or sulfur containing component:
 This subclass is indented under subclass 210.  Processes in which the component is sulfur or a compound thereof.

SEE OR SEARCH THIS CLASS, SUBCLASS:

200+,for separation and purification of a gaseous mixture in which the sulfur is present as hydrogen sulfide.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating sulfur (S) or a compound thereof from a gaseous fluid mixture by physical means only. See particularly subclasses 43+ for selective diffusion of gases, subclasses 90+ for solid sorption, and subclasses 149+ for liquid contacting.
  
[List of Patents for class 423 subclass 242.2]    242.2Utilizing reactant having organic portion to remove or modify sulfur or sulfur containing component:
 This subclass is indented under subclass 242.1.  Process wherein the sulfur or sulfur containing component is removed or changed by treatment with a reactant, a portion of which is an organic compound radical.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   appropriate subclasses, for processes of physically separating sulfur or a compound thereof from a gaseous fluid mixture.
  
[List of Patents for class 423 subclass 242.3]    242.3Organic acid:
 This subclass is indented under subclass 242.2.  Process wherein the reactant is an organic acid (i.e., a compound containing -COOH).
  
[List of Patents for class 423 subclass 242.4]    242.4Alcohol, arylhydroxide, or polyol:
 This subclass is indented under subclass 242.2.  Process wherein the organic portion is an alcohol, an aryl radical, or an organic radical having one or a plurality of hydroxyl groupings (i.e., (OH)-1).
  
[List of Patents for class 423 subclass 242.5]    242.5Sugar:
 This subclass is indented under subclass 242.2.  Process wherein the organic portion is a radical from a sweet carbohydrate, having a general formula of CNH2NON or CNH2N-2ON-1 (e.g., sucrose).
  
[List of Patents for class 423 subclass 242.6]    242.6Heterocyclic:
 This subclass is indented under subclass 242.2.  Process wherein the reactant contains an organic ring portion having a dissimilar atom (e.g., S or N) in the ring.
  
[List of Patents for class 423 subclass 242.7]    242.7Amine:
 This subclass is indented under subclass 242.2.  Process wherein the nitrogen containing reactant is an amine (i.e., NR3 grouping wherein at least one of the R groups is an organic radical).
  
[List of Patents for class 423 subclass 243.01]    243.01Utilizing aqueous reactant to remove or modify sulfur containing component:
 This subclass is indented under subclass 242.1.  Process wherein the sulfur or sulfur containing component is removed or changed by treatment with a reactant dissolved in or contained in water (e.g., solution or slurry).
  
[List of Patents for class 423 subclass 243.02]    243.02And addition of gaseous reactant:
 This subclass is indented under subclass 243.01.  Process wherein a reactant is added that is in a gaseous state at ambient condition (e.g., NH3, Cl2).
(1) Note. Excluded from this subclass are those liquid reactants that have been formed by dissolved gases such as NH4OH that have no specifically recited undissolved gaseous component.

SEE OR SEARCH THIS CLASS, SUBCLASS:

243.1,for those added components dissolved and forming ionic reactants, such as NH4OHNH4+ OH- in alkali or alkaline earth slurry or solution.
  
[List of Patents for class 423 subclass 243.03]    243.03Oxygen:
 This subclass is indented under subclass 243.02.  Process wherein the gaseous reactant includes elemental oxygen.
(1) Note. Elemental oxygen includes oxygen combined only with itself, such as free oxygen (O2) and ozone (O3), but does not include oxygen chemically combined with any other elements or compounds such as carbon monoxide (CO).
  
[List of Patents for class 423 subclass 243.04]    243.04Ion separation step:
 This subclass is indented under subclass 243.01.  Process wherein the treatment takes place by immediate reaction with a product of an ionic separation process, (i.e., dialysis, either by separation using a semipermeable membrane or by electrolysis).

SEE OR SEARCH CLASS:

210Liquid Purification or Separation,   subclasses 600+ for processes of ion separation where a reagent does not immediately react with a product of the separation wherein the intent is to purify a liquid.
  
[List of Patents for class 423 subclass 243.05]    243.05With component added to inhibit corrosion or scaling of processing apparatus:
 This subclass is indented under subclass 243.01.  Process wherein the treatment includes addition of a reactive component whose function is specified to restrain or stop corroding or scaling of processing equipment.

SEE OR SEARCH CLASS:

252Compositions,   subclasses 387+ for corrosion preventing or anti-corrosive agents.
422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 7+ for processes of maintaining an environment non-destructive to metal.
  
[List of Patents for class 423 subclass 243.06]    243.06Ammonium compound reactant:
 This subclass is indented under subclass 243.01.  Process wherein the reactant contains an ammonium (NH4)+1 radical.
  
[List of Patents for class 423 subclass 243.07]    243.07Transition metal or compound thereof reactant:
 This subclass is indented under subclass 243.01.  Process wherein the reactant is a transition metal or a compound thereof.
  
[List of Patents for class 423 subclass 243.08]    243.08Alkali or alkali earth compound reactant:
 This subclass is indented under subclass 243.01.  Process wherein the reactant is an alkali or alkaline earth compound.
  
[List of Patents for class 423 subclass 243.09]    243.09Sulfite:
 This subclass is indented under subclass 243.08.  Process wherein the alkaline component contains a sulfite radical (SO3)-2.
  
[List of Patents for class 423 subclass 243.1]    243.1And additional ionic reactant:
 This subclass is indented under subclass 243.08.  Process wherein the reactant also contains a dissociated ionic reactant other than the alkali or the alkaline earth compound reactant.
(1) Note. Included in this subclass are dissociated ionic components that take part in a reaction that removes or changes the sulfur containing component.

SEE OR SEARCH THIS CLASS, SUBCLASS:

265+,for processes of using additives which do not take part in the reaction, but which serve to improve, protect, or modify a product produced by a separate and distinct reaction.
270+,for additives specifically added when the product is sulfur trioxide.
  
[List of Patents for class 423 subclass 243.11]    243.11And subsequent reactive treatment to remove sulfur from spent reactant:
 This subclass is indented under subclass 243.01.  Process wherein the reactant, after removing or changing the sulfur or sulfur containing component from the gaseous mixture, is subjected to a further reactive treatment wherein sulfur or a sulfur containing component is removed from the reactant.
(1) Note. This subclass contains processes for removing or recovering a sulfur or sulfur containing component.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   subclasses 149+ , for gas separation processes including liquid contacting to remove sulfur or a compound thereof and regenerating of the liquid.
  
[List of Patents for class 423 subclass 243.12]    243.12Gaseous treatment:
 This subclass is indented under subclass 243.11.  Process wherein further reactive treatment is with a reactant in a gaseous state.
  
[List of Patents for class 423 subclass 244.01]    244.01Utilizing solid reactant or catalyst to remove or modify sulfur or sulfur containing component:
 This subclass is indented under subclass 242.1.  Process wherein the sulfur or sulfur containing component is removed or changed by treatment with a reactant or catalyst that is in a solid-state.
  
[List of Patents for class 423 subclass 244.02]    244.02Reactant or catalyst on support:
 This subclass is indented under subclass 244.01.  Process wherein the reactant or catalyst is positioned in contact with a supporting material.
  
[List of Patents for class 423 subclass 244.03]    244.03Carbonaceous support:
 This subclass is indented under subclass 244.02.  Process wherein the support is composed of a carbon containing material (e.g., activated carbon).
  
[List of Patents for class 423 subclass 244.04]    244.04Aluminosilicate support:
 This subclass is indented under subclass 244.02.  Process wherein the support is composed of a material containing a compound of aluminum, oxygen, and silicon.
  
[List of Patents for class 423 subclass 244.05]    244.05Reactant added to fuel for reaction in gas mixture:
 This subclass is indented under subclass 244.01.  Process wherein the reactant is added to a mixture consumed to produce energy.
  
[List of Patents for class 423 subclass 244.06]    244.06Transition metal or compound thereof reactant:
 This subclass is indented under subclass 244.01.  Process wherein the reactant is a transition metal or a compound thereof.
  
[List of Patents for class 423 subclass 244.07]    244.07Alkali or alkaline earth compound reactant:
 This subclass is indented under subclass 244.01.  Process wherein the reactant is a compound that contains an alkali metal or alkaline-earth metal.
  
[List of Patents for class 423 subclass 244.08]    244.08Carbonate:
 This subclass is indented under subclass 244.07.  Process wherein the compound contains a carbonate radical (i.e., (CO3)-2).
  
[List of Patents for class 423 subclass 244.09]    244.09Catalyst:
 This subclass is indented under subclass 244.01.  Process wherein the sulfur or sulfur containing component is treated with a catalyst present.
  
[List of Patents for class 423 subclass 244.1]    244.1Transition metal or compound thereof catalyst:
 This subclass is indented under subclass 244.09.  Process wherein the catalyst includes a transition metal or a compound thereof.
  
[List of Patents for class 423 subclass 244.11]    244.11Zeolite containing:
 This subclass is indented under subclass 244.09.  Process wherein the catalyst contains a zeolite.

SEE OR SEARCH CLASS:

502Catalyst, Solid Sorbent, or Support Therefor: Product or Process of Making,   appropriate subclasses for zeolites specifically structured to catalyze a component.
  
[List of Patents for class 423 subclass 245.1]    245.1Organic component:
 This subclass is indented under subclass 210.  Process wherein the component is an organic compound, at least in part.
(1) Note. See subclass 226 (1) Note for the structural requirement of an organic compound.
(2) Note. The phase of the modifying or removing agent that reacts with the organic component is what determines whether classification is proper in subclass 245.1, subclass 245.2, or substrate wetted with an aqueous hydrogen peroxide removing agent is properly classified in subclass 245.2. Removing agents comprising gases or solids dissolved in liquids are considered to be liquid reactants.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating an organic compound from a gaseous fluid mixture by physical means only. See particularly subclasses 43+ for selective diffusion of gases, subclasses 90+ for solid sorption, and subclasses 149+ for liquid contacting.
  
[List of Patents for class 423 subclass 245.2]    245.2Utilizing liquid reactant:
 This subclass is indented under subclass 245.1.  Process wherein a liquid reactant is utilized to modify or remove the organic component.
  
[List of Patents for class 423 subclass 245.3]    245.3By burning or catalytically combusting component:
 This subclass is indented under subclass 245.1.  Process wherein the organic component is either burned or catalytically combusted using oxygen, air, ozone, or a mixture thereof.
  
[List of Patents for class 423 subclass 246]    246Carbon monoxide component
 This subclass is indented under subclass 210.  Processes wherein the component is carbon monoxide.

SEE OR SEARCH THIS CLASS, SUBCLASS:

212+,for a process for separating or removing constituents from the exhaust of an internal combustion engine, one of which constituents may be carbon monoxide.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating carbon monoxide (CO) from a gaseous fluid mixture by physical means only. See particularly subclasses 43+ for selective diffusion of gases, subclasses 90+ for solid sorption, and subclasses 149+ for liquid contacting.
  
[List of Patents for class 423 subclass 247]    247Utilizing solid sorbent, catalyst, or reactant
 This subclass is indented under subclass 246.  Processes in which the treating material is in the solid-state and functions to (1) modify a component, (2) attract and retain a component or (3) react with and chemically change a constituent.

SEE OR SEARCH THIS CLASS, SUBCLASS:

212+,for a process in which a solid sorbent, catalyst or reactant is used to separate or remove carbon monoxide from the exhaust of an internal combustion engine.
223,for a process of treating a gaseous mixture to separate or purify carbon dioxide or hydrogen sulfide with a reactant containing boron, phosphorus or arsenic, which reactant may be in the solid-state.
230+,239 and 244 for processes for separating or purifying a gaseous mixture by using a solid catalyst, sorbent or reactant where a constituent is carbon dioxide or hydrogen sulfide, nitrogen or a nitrogenous compound or sulfur or a compound thereof respectively.
  
[List of Patents for class 423 subclass 248]    248Hydrogen component
 This subclass is indented under subclass 210.  Processes wherein the component is hydrogen in molecular form.

SEE OR SEARCH THIS CLASS, SUBCLASS:

246+,for processes of removing or separating carbon monoxide from a mixture thereof with hydrogen thus leaving pure hydrogen.

SEE OR SEARCH CLASS:

95Gas Separation: Processes,   for processes of separating hydrogen from a gaseous fluid mixture by physical means only. See particularly subclasses 43+ for selective diffusion of gases, subclasses 90+ for solid sorption, and subclasses 149+ for liquid contacting.
  
[List of Patents for class 423 subclass 249]    249RADIOACTIVE (AT. NO. 84+ OR RADIOACTIVE ISOTOPE OF ANOTHER ELEMENT)
 This subclass is indented under the class definition.  Products , or processes for making such products, which exhibit spontaneous nuclear disintegration with emission of radioactive particles and which comprises (1) the compound of an element which is naturally unstable and has an atomic number of at least 84, (2) compound of an element which has been treated to render an isotope thereof radioactive or (3) a nonmetallic element which is naturally or has been treated to make it or an isotope thereof radioactive; see Glossary.
(1) Note. In this subclass will be found radon, astatine, or compounds thereof.
(2) Note. Compounds, of the trans-actinide elements i.e., those having atomic numbers greater than 103, will be found in this group of subclasses.
(3) Note. Patents wherein the claims are directed to making an element radioactive or to making a different isotope of a radioactive element are classified in Class 376, Induced Nuclear Reactions: Processes, Systems, and Elements, subclasses 156+ even when the element is in compound form.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2+,for a process of treating a mixture to recover therefrom a compound of a radioactive metal.
  
[List of Patents for class 423 subclass 250]    250Transuranium compound
 This subclass is indented under subclass 249.  Products or processes in which the compound comprises an element having an atomic number of 93 or greater.
  
[List of Patents for class 423 subclass 251]    251Plutonium containing
 This subclass is indented under subclass 250.  Products or processes in which the compound comprises plutonium.
  
[List of Patents for class 423 subclass 252]    252Thorium compound
 This subclass is indented under subclass 249.  Products or processes in which the compound comprises thorium.
  
[List of Patents for class 423 subclass 253]    253Uranium compound
 This subclass is indented under subclass 249.  Products or processes which the compound comprises uranium.
  
[List of Patents for class 423 subclass 254]    254Binary compound
 This subclass is indented under subclass 253.  Products or processes in which the compound consists of uranium and only one other elements.
  
[List of Patents for class 423 subclass 255]    255Hydrogen containing
 This subclass is indented under subclass 254.  Products or processes in which the other element is hydrogen.
  
[List of Patents for class 423 subclass 256]    256Carbon containing
 This subclass is indented under subclass 254.  Products or processes in which the other element is carbon.
  
[List of Patents for class 423 subclass 257]    257Chlorine containing
 This subclass is indented under subclass 254.  Products or processes in which the other element is chlorine.
  
[List of Patents for class 423 subclass 258]    258Fluorine containing
 This subclass is indented under subclass 254.  Products or processes in which the other element is fluorine.
  
[List of Patents for class 423 subclass 259]    259Tetrafluoride
 This subclass is indented under subclass 258.  Products or processes in which the binary compound is uranium tetrafluoride (UF4).
  
[List of Patents for class 423 subclass 260]    260Oxygen containing
 This subclass is indented under subclass 254.  Products or processes in which the other element is oxygen.
  
[List of Patents for class 423 subclass 261]    261Dioxide
 This subclass is indented under subclass 260.  Products or processes in which the binary compound is uranium dioxide (UO2).

SEE OR SEARCH THIS CLASS, SUBCLASS:

16,for a process of treating a mixture containing uranium to recover uranium tetraoxide or peroxide, UO4) which process includes the step of precipitating a compound out of solution.
  
[List of Patents for class 423 subclass 262]    262INERT OR NOBLE GAS OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products or processes in which the product is a noble or inert gas having atomic nos. 2, 10, 18, 36, or 54, or a compound thereof; the gas being a member of the "zero" group of the periodic table, having no valency and combining with other elements only with difficulty.

SEE OR SEARCH THIS CLASS, SUBCLASS:

249,for radon (atomic no. 86), which is the radioactive member of the noble or inert gases, or a compound thereof.
  
[List of Patents for class 423 subclass 263]    263RARE EARTH COMPOUND (AT. NO. 21, 39, OR 57-71)
 This subclass is indented under the class definition.  Products or processes in which the product is a compound of a metal which is a member of the "rare earth" or lanthanide series and which has an atomic number of 21, 39, or 57 through 71.

SEE OR SEARCH THIS CLASS, SUBCLASS:

21.1+,for a process of treating a mixture containing a rare earth metal to obtain a compound of the metal.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclass 407 , 412, and 249-260 for the destruction or containment of hazardous or toxic waste containing rare earth or lanthanide elements (atomic numbers 21, 39, or 57-71).
  
[List of Patents for class 423 subclass 264]    264CHANGING COLOR CHARACTERISTIC OF IMPURITY
 This subclass is indented under the class definition.  Processes in which a compound whose color is, or would be, adversely affected by an impurity therein, is treated to chemically modify the impurity and thus improve the color.
(1) Note. Sometimes it is not economically feasible to remove an impurity from a compound which is to be used as a pigment, and so the impurity is changed to a nondetrimental form. For example, Fe2O3 is changed to Fe O which does not effect the color characteristics of titanium dioxide as much as Fe2O3 does.
  
[List of Patents for class 423 subclass 265]    265WITH ADDITIVE
 This subclass is indented under the class definition.  Products or processes comprising a compound or a nonmetallic element physically interrelated with another substance which serves to improve, protect or modify the product, which substance does not take part in the reaction, which makes the product, but is added to the reaction or to the product or is made by a separate and distinct reaction.
(1) Note. A catalyst or other reaction promoter is excluded under this definition of additive.
(2) Note. If in a chemical reaction a reagent is added to combine with a portion of the reactants to form an additive by a reaction other than that which makes the desired product, classification is proper for this group of subclasses.
(3) Note. A substance added to a feedstock to control or modify the product and is carried along in the reaction to be mixed with the product is considered to be additive for this group of subclasses. The final mixture is not considered to be proper for Class 106, Compositions: Coating or Plastic, or Class 252, Compositions unless the disclosure is clear and specific that the product is intended to be a mixture or composition for a specific utility or use. For example, in making carbon black various substances are added to the feedstock to be carried along to the final product and to modify the properties of the carbon black, e.g., oil absorption, crystal structure, etc. These patents are properly classified in this Class 423, subclasses 265+. However, the modified carbon black when disclosed for use as a filler for rubber articles is proper for Class 106, Compositions: Coating and Plastic, subclasses 400+.
(4) Note. Processes of preventing corrosion of metal containers or receptacles by a Class 423 product by admixing an anti-corrosion additive therewith are properly classified in Class 423, subclass 269, since this is the mere use of a product to which an anti-corrosion additive has been added, and since corrosion of the metal causes corrosion of the product. See (1) Note in Class 422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing, subclass 7.
(5) Note. Mixing ingredients to form a composition which is in better form for pyrometallurgy, even though some chemical reaction is involved, excluded from this Class 423 and will be found in Class 75.
(6) Note. Class lines
A. A Class 423 product, per se, is classified in Class 423 regardless of its utility.
B. A Class 423 product admixed with an additive whose sole function (claimed or disclosed) is to otherwise perfect the product is classified in Class 423.
C. The process of making a Class 423 product and adding a preservative thereto is classified in Class 423; the process of merely adding a preservative to a Class 423 product is also classified in Class 423.
D. A Class 423 product admixed with a substance which has one utility other than preserving attributed thereto is classified in the class providing for such utility if such class exists; otherwise classification is proper in Class 252, Compositions.
E. A Class 423 product admixed with a substance which has plural utilities other than preserving attributed thereto, all of which are unclaimed and such utilities are subjects matter for different classes, is proper for Class 252, Compositions.
F. A Class 423 product admixed with a preserving substance and the mixture is disclosed or claimed as having an art use is classified in the class providing for such use, e.g., table salt is properly classified in Class 426, Food or Edible Material: Processes, Compositions, and Products, a fertilizer comprising a phosphate and a preservative is proper for Class 71, Chemistry: Fertilizers.
G. The rules for determining Class placement of the Original Reference (OR) for claimed chemical compositions are set forth in the Class Definition of Class 252 in the section LINES WITH OTHER CLASSES AND WITHIN THIS CLASS, SUBSECTION COMPOSITION CLASS SUPERIORITY, which includes a hierarchical ORDER OF SUPERIORITY FOR COMPOSITION CLASSES.

SEE OR SEARCH CLASS:

8Bleaching and Dyeing; Fluid Treatment and Chemical Modification of Textiles and Fibers,   subclasses 101+ for bleaching processes under the Class 8 definition, and especially Class 107 for processes using specific chemicals.
71Chemistry: Fertilizers,   see (6) Note. Par. F. above.
106Compositions: Coating and Plastic,   see (3) Note above.
252Compositions,   subclasses 186.1+ for oxidative bleaching compositions, per se, and 397+ for anti oxidant and chemical change inhibiting compositions, per se. See also (6) Note. Par. E. above.
260Chemistry of Carbon Compounds,   for (a) carbon compounds of known and undetermined constitution. In the situation wherein it is uncertain whether the compound is prepared by reacting two or more reactants, the original will be classified in Class 260 in accordance with the rule set forth in the Class 260 Definition (Page 260-2) (b) essential oils of undetermined constitution and their reaction products. See subclass 236.6 . Single source essential oils of known constitution combined with plural ingredients having a claimed, or solely disclosed food use are classified in Class 426, Food or Edible Material: Processes, Compositions, and Products. (c) extracts of both plant and animal origin. Same rule applys as in (b) above. (d) proteins, oils and fats from a single source.
422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   see (6) Noteparagraph C above and definitions of Class 422.
424Drug, Bio-Affecting and Body-Treating Compositions,   subclass 62 , for bleach compositions, per se, to be used on live hair or skin, and subclasses 613+ for compositions under the 424 class definitions containing peroxide as an active ingredient.
  
[List of Patents for class 423 subclass 266]    266For stabilizing crystal size or shape
 This subclass is indented under subclass 265.  Products or processes in which the compound or nonmetallic element has a crystalline form and the substance serves to attain a desired crystal shape or size or to prevent change of the desired shape or size.

SEE OR SEARCH CLASS:

23Chemistry: Physical Processes,   subclasses 295+ for processes of crystallization which involve no chemical reaction, in particular, subclasses 300+ for those processes in which an additive is employed.
  
[List of Patents for class 423 subclass 267]    267Including anticaking or antihygroscopic function
 This subclass is indented under subclass 265.  Products or processes in which the substance acts to prevent or reduce (1) the absorption of moisture into the mixture or (2) the cohering of individual particles into larger masses.

SEE OR SEARCH CLASS:

252Compositions,   subclasses 381+ for anti-caking agents in general.
  
[List of Patents for class 423 subclass 268]    268Additive contains organic portion
 This subclass is indented under subclass 267.  Products or processes in which the substance is or includes an organic material.
(1) Note. See subclass 226 (1) Note for structural requirement of an organic compound.

SEE OR SEARCH CLASS:

252Compositions,   subclass 384 , for organic anti-caking agents, per se.
  
[List of Patents for class 423 subclass 269]    269Including corrosion inhibitor
 This subclass is indented under subclass 265.  Products or processes which the substance prevents or inhibits the compound or non metallic element from eroding or eating away materials external to the product.

SEE OR SEARCH CLASS:

106Compositions: Coating and Plastic,   especially subclass 14.05 , for compositions of the Class 106 type having a specific corrosion resisting effect beyond mere coating.
148Metal Treating,   especially subclasses 240+ for methods of inhibiting corrosion of metals which include coating the metal with a substance which reacts with the metal.
252Compositions,   subclasses 387+ , for corrosion inhibiting compositions, per se.
422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 1+ for processes of preventing corrosion not elsewhere provided for.
  
[List of Patents for class 423 subclass 270]    270For sulfur trioxide
 This subclass is indented under subclass 265.  Products or processes in which the product is sulfur trioxide (SO3).
(1) Note. The substance is usually added for the purpose of preventing polymerization of the SO3.

SEE OR SEARCH THIS CLASS, SUBCLASS:

532+,for sulfur trioxide, per se, and processes for its manufacture.
  
[List of Patents for class 423 subclass 271]    271Additive contains metal, boron, or silicon
 This subclass is indented under subclass 270.  Products or processes in which the substance is a metal, boron or silicon, or a compound thereof.
  
[List of Patents for class 423 subclass 272]    272For hydrogen peroxide
 This subclass is indented under subclass 265.  Products or processes which the product is hydrogen peroxide (H2O2).

SEE OR SEARCH THIS CLASS, SUBCLASS:

584+,for hydrogen peroxide and methods for making it.
  
[List of Patents for class 423 subclass 273]    273Additive contains metal, boron, or silicon
 This subclass is indented under subclass 272.  Products or processes in which the substance is a metal, boron or silicon, or a compound thereof.
  
[List of Patents for class 423 subclass 274]    274Coating or binder
 This subclass is indented under subclass 265.  Products or processes in which the substance is interrelated as a (1) covering over at least part of the surface of the product or (2) a binder causing the particles of the product to adhere to one another.
(1) Note. The coating or binder generally does not interfere, to any undue extent, with the reactivity of the product when such reactivity is desired.

SEE OR SEARCH CLASS:

264Plastic and Nonmetallic Article Shaping or Treating: Processes,   for briquetting or otherwise shaping the compositions of this subclass.
424Drug, Bio-Affecting and Body-Treating Compositions,   subclasses 16+ , for coated compositions meeting the Class 424 definition.
427Coating Processes,   for general processes of coating. The process of making and coating a Class 423 product is properly classified in Class 423 where the purpose of the coating is merely to preserve or stabilize the product. The process of coating a Class 423 product is proper for Class 427, and a coated Class 423 product is proper for Class 423.
  
[List of Patents for class 423 subclass 275]    275Additive contains metal, boron, or silicon
 This subclass is indented under subclass 265.  Products or processes in which the substance is a metal, boron or silicon, or a compound thereof.
  
[List of Patents for class 423 subclass 276]    276BORON OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products or processes wherein the product is boron or a compound thereof.
  
[List of Patents for class 423 subclass 277]    277Oxygen containing
 This subclass is indented under subclass 276.  Products or processes wherein the boron compound includes oxygen.
  
[List of Patents for class 423 subclass 278]    278Binary compound
 This subclass is indented under subclass 277.  Products or processes wherein the compound contains only the elements boron and oxygen.
  
[List of Patents for class 423 subclass 279]    279Ternary compound containing metal or ammonium
 This subclass is indented under subclass 277.  Products or processes wherein the compound contains only boron, oxygen and either a metal or the ammonium radical.
(1) Note. Under this definition the ammonium (NH4+) radical is considered as only 1 element of the ternary compound; see (2) Note of the main class definition.
  
[List of Patents for class 423 subclass 280]    280Utilizing dissolved or liquid reactant
 This subclass is indented under subclass 279.  Processes which includes the use of at least one reactant in the liquid state or in solution.
(1) Note. Included under the definition of dissolved or liquid reactant is a slurry of solids in a liquid.
  
[List of Patents for class 423 subclass 281]    281Peroxide
 This subclass is indented under subclass 280.  Processes in which the reactant comprises a peroxide.
  
[List of Patents for class 423 subclass 282]    282Carbon containing
 This subclass is indented under subclass 280.  Processes in which the reactant comprises a compound containing the element carbon.
  
[List of Patents for class 423 subclass 283]    283Ternary compound containing hydrogen
 This subclass is indented under subclass 277.  Products or processes wherein the compound contains only the three elements, boron, oxygen and hydrogen.
  
[List of Patents for class 423 subclass 284]    284Nitrogen and hydrogen containing
 This subclass is indented under subclass 276.  Products or processes in which the compound also contains nitrogen and hydrogen.
  
[List of Patents for class 423 subclass 285]    285Ternary compound
 This subclass is indented under subclass 284.  Products or processes in which the compound contains only the three elements boro, hydrogen and nitrogen.
  
[List of Patents for class 423 subclass 286]    286Hydrogen and metal or ammonium containing
 This subclass is indented under subclass 276.  Products or processes in which the compound also contains hydrogen and either a metal or the ammonium (NH4+).
  
[List of Patents for class 423 subclass 287]    287Utilizing halogen containing reactant
 This subclass is indented under subclass 286.  Processes which include the use of a halogen containing compound as a reactant.
  
[List of Patents for class 423 subclass 288]    288Utilizing oxygen containing reactant
 This subclass is indented under subclass 286.  Processes which include the use of an oxygen containing compound as a reactant.
  
[List of Patents for class 423 subclass 289]    289Binary compound (e.g., boride, etc.)
 This subclass is indented under subclass 276.  Products and processes in which the compound contains boron and only one other element.

SEE OR SEARCH THIS CLASS, SUBCLASS:

278,for binary compounds containing boron and oxygen and methods of making such compounds.
  
[List of Patents for class 423 subclass 290]    290Nitrogen containing
 This subclass is indented under subclass 289.  Products of processes wherein the other element is nitrogen.
  
[List of Patents for class 423 subclass 291]    291Carbon containing
 This subclass is indented under subclass 289.  Products or processes wherein the other element is carbon.
  
[List of Patents for class 423 subclass 292]    292Halogen containing
 This subclass is indented under subclass 289.  Products or processes wherein the other element is a halogen.
  
[List of Patents for class 423 subclass 293]    293Fluorine
 This subclass is indented under subclass 292.  Products or processes wherein the halogen is fluorine.
  
[List of Patents for class 423 subclass 294]    294Hydrogen containing
 This subclass is indented under subclass 289.  Products or processes wherein the other element is hydrogen.
  
[List of Patents for class 423 subclass 295]    295By reacting metal hydride or organic derivative thereof
 This subclass is indented under subclass 294.  Processes which include the step of reacting a metal containing hydride or an organic derivative thereof.
  
[List of Patents for class 423 subclass 296]    296By reacting free hydrogen
 This subclass is indented under subclass 294.  Processes which include the step of reacting elemental or uncombined hydrogen.
  
[List of Patents for class 423 subclass 297]    297Refractory metal containing (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, or W)
 This subclass is indented under subclass 289.  Products or processes wherein the other element is titanium, vanadium chromium, zirconium, niobium, molybdenum, hafnium, tantalum, or tungsten, commonly known as a refractory metal.
  
[List of Patents for class 423 subclass 298]    298Elemental boron
 This subclass is indented under subclass 276.  Products or processes wherein the product is elemental boron.
  
[List of Patents for class 423 subclass 299]    299PHOSPHORUS OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products or processes wherein the product is phosphorus or a compound thereof.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing, halogen, oxygen, sulfur, metal, and phosphorus.
  
[List of Patents for class 423 subclass 300]    300Halogen containing
 This subclass is indented under subclass 299.  Products or processes wherein the product contains a halogen.
  
[List of Patents for class 423 subclass 301]    301Fluorine
 This subclass is indented under subclass 300.  Products or processes wherein the halogen is fluorine.
  
[List of Patents for class 423 subclass 302]    302Nitrogen containing
 This subclass is indented under subclass 299.  Products or processes wherein the product contains nitrogen.
(1) Note. Nitrogen in the ammonium radical (NH4+) is not considered nitrogen for the purpose of this subclass; see (2) Note in the class definition.
  
[List of Patents for class 423 subclass 303]    303Sulfur containing
 This subclass is indented under subclass 299.  Products or processes wherein the product contains sulfur.
  
[List of Patents for class 423 subclass 304]    304Oxygen containing
 This subclass is indented under subclass 299.  Products or processes wherein the product contains oxygen.
  
[List of Patents for class 423 subclass 305]    305Metal or ammonium containing
 This subclass is indented under subclass 304.  Products or processes wherein the product also contains a metal or the ammonium (NH4+) radical.

SEE OR SEARCH THIS CLASS, SUBCLASS:

237+,for a process of preparing ammonium phosphate from the ammonia in gas where the mains intent is to purify the gas, the recovery of the product being of secondary importance.
  
[List of Patents for class 423 subclass 306]    306Plural metal or metal and ammonium containing
 This subclass is indented under subclass 305.  Products or processes wherein the product contains two metals or a metal and the ammonium (NH4+) radical.
  
[List of Patents for class 423 subclass 307]    307Hydrogen containing
 This subclass is indented under subclass 305.  Products or processes wherein the product also contains hydrogen.
  
[List of Patents for class 423 subclass 308]    308Orthophosphate (e.g., calcium hydroxyapatite)
 This subclass is indented under subclass 307.  Products or processes wherein the product contains the orthophosphate (PO43-) radical.
  
[List of Patents for class 423 subclass 309]    309Utilizing phosphoric acid or its anhydride as reactant
 This subclass is indented under subclass 308.  Processes which include the step of reacting phosphoric acid or its anhydride.
  
[List of Patents for class 423 subclass 310]    310And ammonia
 This subclass is indented under subclass 309.  Processes which include the step of reacting ammonia.
  
[List of Patents for class 423 subclass 311]    311Orthophosphate
 This subclass is indented under subclass 305.  Products or processes wherein the product contains the orthophosphate (PO43-) radical.
  
[List of Patents for class 423 subclass 312]    312Alkali metal or ammonium containing
 This subclass is indented under subclass 311.  Products or processes wherein the product contains lithium, sodium, potassium, rudidium, cesium or the ammonium (NH4+) radical.
  
[List of Patents for class 423 subclass 313]    313Utilizing phosphoric acid as reactant
 This subclass is indented under subclass 312.  Processes which includes the step of reacting phosphoric acid.
  
[List of Patents for class 423 subclass 314]    314Metaphosphate
 This subclass is indented under subclass 305.  Products or processes wherein the product contains the meta-phosphate (PO3-), (P2O62-) or (P6O186) radical.
  
[List of Patents for class 423 subclass 315]    315Triphosphate or tetraphosphate
 This subclass is indented under subclass 305.  Products or processes wherein the product contains the triphosphate (P3O105-) or the tetraphosphate (P4O136-) radical.
  
[List of Patents for class 423 subclass 316]    316Ternary compound containing hydrogen
 This subclass is indented under subclass 304.  Products or processes wherein the product contains phosphorus, oxygen and hydrogen, only.
  
[List of Patents for class 423 subclass 317]    317Orthophosphoric acid
 This subclass is indented under subclass 316.  Products or processes wherein the product is orthophosphoric acid (H3PO4).
  
[List of Patents for class 423 subclass 318]    318Utilizing reactant containing silicon or carbon
 This subclass is indented under subclass 317.  Processes which include the step of reacting silicon or carbon, or a compound thereof.
  
[List of Patents for class 423 subclass 319]    319Reacting an acid and phosphate rock
 This subclass is indented under subclass 317.  Processes which include the step of reacting an acid with phosphate rock.
  
[List of Patents for class 423 subclass 320]    320Sulfuric acid
 This subclass is indented under subclass 319.  Processes in which the acid includes sulfuric acid (H2SO4).
  
[List of Patents for class 423 subclass 321.1]    321.1Purification or recovery:
 This subclass is indented under subclass 317.  Process wherein the product is separated from impurities or undesired foreign matter.
  
[List of Patents for class 423 subclass 321.2]    321.2Organic solvent extraction:
 This subclass is indented under subclass 321.1.  Process wherein separation is by dissolution in an organic liquid.
(1) Note. Dissolution may be of product or impurity.
  
[List of Patents for class 423 subclass 322]    322Elemental phosphorus
 This subclass is indented under subclass 299.  Products or processes wherein the product is elemental phosphorus.
(1) Note. Changing yellow phosphorus to red phosphorus involves a chemical reaction since the water of hydration is changed, see (9) Note in the class definition.
  
[List of Patents for class 423 subclass 323]    323Utilizing a phosphate as reactant
 This subclass is indented under subclass 322.  Processes which include the step of reacting a material which contains a phosphate (PO43-) radical, e.g., phosphate rock, etc.
  
[List of Patents for class 423 subclass 324]    324SILICON OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products and processes wherein the product is silicon or a compound thereof.
(1) Note. Silicon and silicon dioxide are arbitrarily considered to be glass. A process of chemically manufacturing silicon or silicon dioxide combined with significant shaping or heat treatment will be found in either Class 438, Semiconductor Device Manufacturing: Process, or Class 65, Glass Manufacturing.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing silicon, oxygen, and metals.
  
[List of Patents for class 423 subclass 325]    325Oxygen containing
 This subclass is indented under subclass 324.  Products or processes wherein the product contains oxygen.
  
[List of Patents for class 423 subclass 326]    326Metal containing (i.e., silicate)
 This subclass is indented under subclass 325.  Products or processes wherein the product also contains at least one metal.
  
[List of Patents for class 423 subclass 327.1]    327.1Aluminum containing:
 This subclass is indented under subclass 326.  Products or processes in which the metal is aluminum.
  
[List of Patents for class 423 subclass 327.2]    327.2Mullite:
 This subclass is indented under subclass 327.1.  Products and processes in which the product is mullite (i.e., 3Al2O3 2SiO2).
  
[List of Patents for class 423 subclass 328.1]    328.1Aluminosilicate:
 This subclass is indented under subclass 327.1.  Product or processes in which the product is an aluminum silicate in combination with a metal oxide.

SEE OR SEARCH THIS CLASS, SUBCLASS:

118,for processes of treating mixtures to obtain an aluminosilicate.
  
[List of Patents for class 423 subclass 328.2]    328.2Crystalline:
 This subclass is indented under subclass 328.1.  Products and processes in which the products have geometrically arranged plane faces or surfaces and a symmetrical internal structure (e.g., pillared or phyllosilicates).
(1) Note. Crystalline aluminosilicates, such as sorbents, are to be considered products for Class 423, unless mixed with an additive whose function is not solely to perfect the product. See (6) Note to the definition of subclass 265.
(2) Note. Three dimension crystalline structural products that are zeolites are excluded from this subclass. See (2) Note to the definition of subclass 700.

SEE OR SEARCH THIS CLASS, SUBCLASS:

700,for products and processes wherein the product is a zeolite.

SEE OR SEARCH CLASS:

501Compositions: Ceramic,   subclasses 141+ for ceramic compositions and processes for producing such.
  
[List of Patents for class 423 subclass 328.3]    328.3Mica:
 This subclass is indented under subclass 328.2.  Products and processes in which the geometrical arrangement has a lamina structure which can be split into thin sheets (e.g., biovite, muscovite, phlogopite, zinnwaldite).
  
[List of Patents for class 423 subclass 329.1]    329.1X-ray diffraction pattern:
 This subclass is indented under subclass 328.1.  Products wherein the aluminosilicate structure is identified by a diffraction grating produced by an X-ray passing through it.
(1) Note. Original patents in this subclass require that an X-ray diffraction pattern be referenced in the claim.
  
[List of Patents for class 423 subclass 330.1]    330.1Gelling or precipitation:
 This subclass is indented under subclass 328.1.  Processes which include either forming a gel or causing a substance to come out of solution.
  
[List of Patents for class 423 subclass 331]    331Alkaline earth metal containing (Mg, Ca, Sr, or Ba)
 This subclass is indented under subclass 326.  Products or processes in which the product contains magnesium, calcium, strontium or barium (i.e., the alkaline earth metals).
  
[List of Patents for class 423 subclass 332]    332Alkali metal containing (Li, Na, K, Rb, or Cs)
 This subclass is indented under subclass 326.  Products or processes in which the product contains lithium, sodium, potassium, rubidium or cesium (i.e. an alkali metal).
  
[List of Patents for class 423 subclass 333]    333By precipitating or gelling from silicate solution
 This subclass is indented under subclass 332.  Processes which include the step of causing a substance to become insoluble and come out of solution or to become a jelly like mass in a solution, the solution being that of the silicate of an alkali metal.
  
[List of Patents for class 423 subclass 334]    334By heat treating silica and the alkali metal
 This subclass is indented under subclass 332.  Processes which include the step of reacting the alkali metal with silica (silicon dioxide) while heating.
  
[List of Patents for class 423 subclass 335]    335Silica
 This subclass is indented under subclass 325.  Products or processes in which the product is silicon dioxide (Si O2).
  
[List of Patents for class 423 subclass 336]    336By hydrolyzing vapor phase silicon compound
 This subclass is indented under subclass 335.  Processes which include the step of hydrolyzing a silicon compound while in the vapor phase.
  
[List of Patents for class 423 subclass 337]    337By oxidizing volatile silicon compound (e.g., combustion, etc.)
 This subclass is indented under subclass 335.  Processes which include the step of causing (1) a volatile silicon compound to unite with oxygen or (2) an increase of electronegative elements or radicals in a volatile silicon compound.
(1) Note. Combustion is a form of oxidation and is included under this definition.
  
[List of Patents for class 423 subclass 338]    338By gelling
 This subclass is indented under subclass 335.  Processes which include the step of gellation or forming a jelly like mass.
  
[List of Patents for class 423 subclass 339]    339By precipitating
 This subclass is indented under subclass 335.  Processes which include the step of causing a substance to come out of solution or become insolubilized.
  
[List of Patents for class 423 subclass 340]    340By purifying sand
 This subclass is indented under subclass 335.  Processes which include the step of purifying silicon dioxide.
  
[List of Patents for class 423 subclass 341]    341Halogen containing
 This subclass is indented under subclass 324.  Products or processes wherein the product contains a halogen.
  
[List of Patents for class 423 subclass 342]    342Halogenated silane
 This subclass is indented under subclass 341.  Products or processes in which the product is similar to a halogenated hydrocarbon in which a tetravalent silicon replaces the carbon atom; (silane is SiH4, trichlorosilane is SiHCl3).

SEE OR SEARCH THIS CLASS, SUBCLASS:

347,for the binary silane compound.
  
[List of Patents for class 423 subclass 343]    343Volatizing a solid
 This subclass is indented under subclass 341.  Processes which include the step of causing a normally solid substance to pass into a gas or a vapor; see Glossary.
  
[List of Patents for class 423 subclass 344]    344Binary compound (e.g., silicide, etc.)
 This subclass is indented under subclass 324.  Products or processes wherein the product is a compound containing silicon and only one additional element.

SEE OR SEARCH THIS CLASS, SUBCLASS:

335+,for binary silicon and oxygen containing compounds.
341+,for halogen containing compounds which may be binary.
  
[List of Patents for class 423 subclass 345]    345Of carbon (i.e., silicon carbide)
 This subclass is indented under subclass 344.  Products or processes wherein the additional element is carbon.
  
[List of Patents for class 423 subclass 346]    346By reacting vapor phase silicon compound with carbon or carbon containing compound
 This subclass is indented under subclass 345.  Processes which include the step of reacting carbon or a carbon containing compound with a silicon containing compound that is in the vapor phase.
  
[List of Patents for class 423 subclass 347]    347Of hydrogen (e.g., silane, etc.)
 This subclass is indented under subclass 344.  Products or processes in which the additional element is hydrogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

342,for halogen derivatives of the binary silanes.
  
[List of Patents for class 423 subclass 348]    348Elemental silicon
 This subclass is indented under subclass 324.  Products or processes wherein the product is elemental silicon.

SEE OR SEARCH CLASS:

117Single-Crystal, Oriented-Crystal, and Epitaxy Growth Processes; Non-Coating Apparatus Therefor,   especially subclasses 54+ for liquid phase epitaxial growth processes and subclasses 84+ for vapor phase growth processes.
438Semiconductor Device Manufacturing,   particularly subclasses 478+ for methods of depositing semiconductive silicon which is to function as an active region of a barrier layer device.
  
[List of Patents for class 423 subclass 349]    349From silicon containing compound
 This subclass is indented under subclass 348.  Processes wherein the starting materials include a silicon containing compound.
  
[List of Patents for class 423 subclass 350]    350Utilizing reducing substance
 This subclass is indented under subclass 349.  Processes which include the use of a reducing element, compound or composition to release the silicon from the compound.
(1) Note. Heat is not a reducing "substance" for the purposes of this subclass. If only heat is used to reduce the silicon containing compound the patent is classified in subclass 349 above.
  
[List of Patents for class 423 subclass 351]    351NITROGEN OR COMPOUND THEREOF (EXCEPT AMMONIUM SALT OF NON-NITROGEN ACID)
 This subclass is indented under the class definition.  Products or processes in which the product is nitrogen or a compound thereof, limited as follows: where the compound is an ammonium (NH4+) salt, the anion must contain a nitrogen atom.
(1) Note. Ammonium hydroxide (NH4OH) is included under this definition.

SEE OR SEARCH THIS CLASS, SUBCLASS:

217,for the process of separating or obtaining nitrogen from atmospheric air where it is the intent to separate components of or purify the air.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing nitrogen, oxygen, halogen, and metals.
  
[List of Patents for class 423 subclass 352]    352Ammonia or ammonium hydroxide
 This subclass is indented under subclass 351.  Products or processes wherein the product is ammonia (NH3), or ammonium hydroxide (NH4OH).
  
[List of Patents for class 423 subclass 353]    353From nitride of metal or silicon
 This subclass is indented under subclass 352.  Processes in which the product is made from the nitride of a metal or of silicon.
(1) Note. Where a metal or metal compound is contacted alternately with free nitrogen and free hydrogen and ammonia is produced, it is assumed that the nitrogen contact produces a nitride which is converted to ammonia in the later contact with hydrogen, and classification in this subclass is proper.
  
[List of Patents for class 423 subclass 354]    354And producing inorganic carbon and nitrogen containing compound
 This subclass is indented under subclass 352.  Processes in which an inorganic compound containing carbon and nitrogen is also made.
(1) Note. The inorganic compound is usually a cyanide or cyanamide.
(2) Note. The manufacture of the inorganic compound may precede or be similtananeous with the manufacture of the ammonia.
  
[List of Patents for class 423 subclass 355]    355By hydrolyzing inorganic carbon and nitrogen containing compound
 This subclass is indented under subclass 352.  Processes which include the step of hydrolyzing an inorganic compound containing carbon and nitrogen.
(1) Note. The inorganic compound is usually a cyanide or cyanamide.
(2) Note. The hydrolyzing agent is usually steam.
  
[List of Patents for class 423 subclass 356]    356From ammonium compound
 This subclass is indented under subclass 352.  Processes in which the product is made from a compound containing the ammonium (NH4+) radical.
(1) Note. The processes usually involve contact of the compound with steam.
(2) Note. The nitrogen in inorganic salts such as NH4Cl and (NH4)2SO4 is often referred to as "fixed nitrogen" in these patents.
  
[List of Patents for class 423 subclass 357]    357Utilizing calcium compound
 This subclass is indented under subclass 356.  Processes in which a compound containing the element calcium (Ca-+) is used.
  
[List of Patents for class 423 subclass 358]    358From organic material containing nitrogen
 This subclass is indented under subclass 352.  Processes in which the product is made from a substance which contains nitrogen and is of organic structure.
(1) Note. The organic material is frequently a waste product or of undetermined constitution.
(2) Note. The reaction often is a steam hydrolysis.
(3) Note. See subclass 226 (1) Note for structural requirement of an organic material.

SEE OR SEARCH THIS CLASS, SUBCLASS:

550,for processes wherein ammonia from waste gases is recovered as ammonium sulfate.
  
[List of Patents for class 423 subclass 359]    359From elemental hydrogen and nitrogen
 This subclass is indented under subclass 352.  Processes in which the product is made from elemental hydrogen and nitrogen.
  
[List of Patents for class 423 subclass 360]    360With exchanging heat between catalyst and synthesis or effluent gas
 This subclass is indented under subclass 359.  Processes including the step of exchanging heat values between a catalyst used in the process and the mixture of gases either prior to, or subsequent to, the reaction.
  
[List of Patents for class 423 subclass 361]    361Utilizing plurality of catalyst beds or portions
 This subclass is indented under subclass 359.  Processes which include the use of more than a single catalyst bed, or in which different portions of a single catalyst bed are subjected to different processing conditions, e.g., temperature, pressure, composition of reactant mixture, etc.
  
[List of Patents for class 423 subclass 362]    362Utilizing metal containing catalyst
 This subclass is indented under subclass 359.  Processes in which a catalyst comprising a metal is utilized.
  
[List of Patents for class 423 subclass 363]    363Alkali or alkaline earth metal
 This subclass is indented under subclass 362.  Processes in which the metal is lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium.
  
[List of Patents for class 423 subclass 364]    364Carbon containing
 This subclass is indented under subclass 351.  Products or processes in which the product also comprises carbon.
  
[List of Patents for class 423 subclass 365]    365And oxygen containing (e.g., fulminate, cyanate, etc.)
 This subclass is indented under subclass 364.  Products or processes in which the product also contains oxygen.
  
[List of Patents for class 423 subclass 366]    366And sulfur containing (e.g., thiocyanate, etc.)
 This subclass is indented under subclass 364.  Products or processes wherein the product also contains sulfur.
  
[List of Patents for class 423 subclass 367]    367And iron containing (e.g., ferrocyanide, etc.)
 This subclass is indented under subclass 364.  Products or processes wherein the product also contains iron.
  
[List of Patents for class 423 subclass 368]    368Cyanamide radical containing
 This subclass is indented under subclass 364.  Products or processes in which the carbon is combined with nitrogen as the cyanamide radical (CN2-1).
(1) Note. In this subclass are found salts of cyanamide. For hydrogen cyanamide see search note below.

SEE OR SEARCH THIS CLASS, SUBCLASS:

369,for processes of making hydrogen cyanamide or for chemically separating or purifying the product.
371,for processes producing carbonitrides having formulas wherein carbon and nitrogen atoms are present in the ratio of one carbon to two nitrogens, but are not clearly cyanamide compounds.

SEE OR SEARCH CLASS:

260Chemistry of Carbon Compounds,   for cyanamide polymers such as dicyandiamide and melamine.
  
[List of Patents for class 423 subclass 369]    369And hydrogen containing
 This subclass is indented under subclass 368.  Products or processes wherein the compound contains hydrogen and is usually named cyanamide, but may also be called cyanogenamide or carbodiimide, and has the formula HN:CNH (H2CH2) or N:CNH2 (H2NCH).

SEE OR SEARCH THIS CLASS, SUBCLASS:

368,for processes of separating, purifying or manufacturing the cyanamide salt or a metal or the ammonium radical.
  
[List of Patents for class 423 subclass 370]    370Utilizing carbide as reactant
 This subclass is indented under subclass 368.  Processes which include the step of using a carbide as a reactant.
  
[List of Patents for class 423 subclass 371]    371Ternary compound
 This subclass is indented under subclass 364.  Products or processes in which the product consists of only one element in addition to the carbon and nitrogen.
(1) Note. The ammonium (NH4+!) radical is considered to be a single element, see (1) Note to the class definition.
  
[List of Patents for class 423 subclass 372]    372Hydrogen cyanide
 This subclass is indented under subclass 371.  Products or processes in which the product is hydrogen cyanide (HCN), which may also be designated as hydrocyanic acid, prussic acid, or formonitrile.
  
[List of Patents for class 423 subclass 373]    373Employing formamide or formate as reactant
 This subclass is indented under subclass 372.  Processes including the use of formamide (HCONH2) or of a compound containing the formamide (HCONH-) radical or of a compound containing the formate (HCOO-) radical.
(1) Note. The formate is usually in the form of the ammonium salt.
  
[List of Patents for class 423 subclass 374]    374Utilizing nitric oxide or free nitrogen as reactant
 This subclass is indented under subclass 372.  Processes which include the use of free nitrogen or nitric oxide in a reaction.
(1) Note. The presence of air in the reaction zone is not sufficient to classify a patent herein, unless clearly disclosed as the source of nitrogen.
  
[List of Patents for class 423 subclass 375]    375Employing ammonia as reactant
 This subclass is indented under subclass 372.  Processes including the use of ammonia in a reaction.
  
[List of Patents for class 423 subclass 376]    376And using catalyst
 This subclass is indented under subclass 375.  Processes wherein a catalyst is used.
  
[List of Patents for class 423 subclass 377]    377Utilizing metal cyanide as reactant
 This subclass is indented under subclass 372.  Processes including the use of a cyanide of a metal in a reaction.
(1) Note. Solutions and solids which contain undefined "cyanides" and are acidified, thus producing the product, are presumed to be metal cyanides for this subclass.

SEE OR SEARCH CLASS:

422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclass 36 for process of sterilizing or disinfecting using cyanide.
  
[List of Patents for class 423 subclass 378]    378Using cyanamide as reactant
 This subclass is indented under subclass 371.  Processes which include the use of cyanamide or a cyanamide salt in a reaction.
  
[List of Patents for class 423 subclass 379]    379Utilizing hydrogen cyanide as reactant
 This subclass is indented under subclass 371.  Processes which include the use of hydrogen cyanide (HCH) in a reaction.
  
[List of Patents for class 423 subclass 380]    380Utilizing free nitrogen as reactant
 This subclass is indented under subclass 371.  Processes including the use of elemental or free nitrogen in a reaction.
(1) Note. The presence of atompheric air in the reaction is not sufficient to classify a patent in this subclass, unless clearly disclosed as the source of nitrogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

374,for a process in which free or elemental nitrogen is used in the manufacture of hydrogen cyanide.
  
[List of Patents for class 423 subclass 381]    381And using catalyst
 This subclass is indented under subclass 380.  Processes which include the use of a catalyst.
  
[List of Patents for class 423 subclass 382]    382Utilizing carbon reactant from specified source
 This subclass is indented under subclass 380.  Processes which also include the use of carbon in a reaction and which is further disclosed as originationg from a particular source, e.g., charcoal, a carbide, oil, etc.
(1) Note. Where the reactant is described merely as "carbon" or "carbonaceous", this is not sufficient for classification herein.
  
[List of Patents for class 423 subclass 383]    383Halogen containing
 This subclass is indented under subclass 364.  Products or processes in which the product also contains a halogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

371+,for products and processes for making such products in which the halogen is one of three elements in a ternary compound.
  
[List of Patents for class 423 subclass 384]    384Binary (e.g., cyanogen, etc.)
 This subclass is indented under subclass 364.  Processes in which only nitrogen and carbon form the product, e.g., cyanogen (C2N2).
  
[List of Patents for class 423 subclass 385]    385Oxygen containing
 This subclass is indented under subclass 351.  Products or processes in which the product also contains oxygen.
  
[List of Patents for class 423 subclass 386]    386Halogen containing
 This subclass is indented under subclass 385.  Products or processes wherein the product also contains a halogen.
  
[List of Patents for class 423 subclass 387]    387Hydrogen containing
 This subclass is indented under subclass 585.  Products or processes wherein the product also contains hydrogen.
  
[List of Patents for class 423 subclass 388]    388Sulfur containing
 This subclass is indented under subclass 387.  Products or processes in which the product also contains sulfur.
  
[List of Patents for class 423 subclass 389]    389Sulfamic acid
 This subclass is indented under subclass 388.  Products or processes wherein the product is sulfamic acid or aminosulfonic acid, having one of the following formulas: HSO-3HN2, NH2SO3H or H2NSO3H.
  
[List of Patents for class 423 subclass 390.1]    390.1Nitric acid:
 This subclass is indented under subclass 387.  Products and processes in which the product is nitric acid; i.e., HNO3.

SEE OR SEARCH THIS CLASS, SUBCLASS:

400,for processes for the production of nitrogen oxides, per se.
  
[List of Patents for class 423 subclass 391]    391By reacting a salt and an acid
 This subclass is indented under subclass 390.1.  Processes which include the step of contacting a salt and an acid for a reaction.
  
[List of Patents for class 423 subclass 392]    392Utilizing ammonia as reactant
 This subclass is indented under subclass 390.1.  Processes which include the use of ammonia in a reaction.
  
[List of Patents for class 423 subclass 393]    393Utilizing nitrogen oxide as reactant
 This subclass is indented under subclass 390.1.  Processes in which an oxide of nitrogen is used as a reactant.
(1) Note. For this and the indented subclass the "reactant" may or may not be the starting material. The "reactant" may be used to make an intermediate product which is then used to make the desired product or the "reactant" may be used to directly make the desired product.

SEE OR SEARCH THIS CLASS, SUBCLASS:

392,for processes in which ammonia is oxidized to form a nitrogen oxide as an intermediate product.
  
[List of Patents for class 423 subclass 394]    394Nitrogen peroxide
 This subclass is indented under subclass 393.  Processes in which the nitrogen oxide is nitrogen peroxide, (NO2or N2 O4).
  
[List of Patents for class 423 subclass 394.2]    394.2Purification or recovery:
 This subclass is indented under subclass 390.1.  Processes wherein the nitric acid is separated from impurities or undesired foreign matter.
  
[List of Patents for class 423 subclass 395]    395Nitrate
 This subclass is indented under subclass 385.  Products or processes wherein the product contains the nitrate radical (NO3-).
(1) Note. Included under this definition are double salts of the nitrate radical, such as NaNO3. CaSO4.

SEE OR SEARCH THIS CLASS, SUBCLASS:

396,for processes wherein ammonium nitrate is made by reacting a nitrate.
  
[List of Patents for class 423 subclass 396]    396Ammonium containing
 This subclass is indented under subclass 395.  Products or processes wherein the product contains the ammonium (NH4+) radical.
  
[List of Patents for class 423 subclass 397]    397Utilizing ammonium or metal nitrate as reactant
 This subclass is indented under subclass 395.  Processes which include the use of a nitrate compound containing a metal or the ammonium (NH4+) ion as a reactant.
  
[List of Patents for class 423 subclass 398]    398Utilizing halogen containing reactant
 This subclass is indented under subclass 395.  Processes in which a compound containing a halogen is used as a reactant.
  
[List of Patents for class 423 subclass 399]    399And nitric acid reactant
 This subclass is indented under subclass 398.  Processes which also include the use of nitric acid (HNO3) as as a reactant.
  
[List of Patents for class 423 subclass 400]    400Binary compound (oxide of nitrogen)
 This subclass is indented under subclass 385.  Products or processes wherein the product contains only nitrogen and oxygen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

390.1,for processes for the production of nitric acid, which may include production of nitrogen oxides.
  
[List of Patents for class 423 subclass 401]    401Utilizing nitrosyl chloride as reactant
 This subclass is indented under subclass 400.  Processes which include the use of nitrosyl chloride (NOC1) as a reactant.
  
[List of Patents for class 423 subclass 402]    402Utilizing catalyst
 This subclass is indented under subclass 400.  Processes in which a catalyst is used.
  
[List of Patents for class 423 subclass 403]    403And ammonia as reactant
 This subclass is indented under subclass 402.  Processes which include the use of ammonia as a reactant.
  
[List of Patents for class 423 subclass 404]    404Catalyst is metal oxide
 This subclass is indented under subclass 403.  Processes wherein the catalyst contains the oxide of a metal.
  
[List of Patents for class 423 subclass 405]    405Nitric oxide (NO)
 This subclass is indented under subclass 400.  Processes wherein the product is nitric oxide (NO).
  
[List of Patents for class 423 subclass 406]    406Binary compound
 This subclass is indented under subclass 351.  Products or processes wherein the product includes nitrogen and only one additional element.

SEE OR SEARCH THIS CLASS, SUBCLASS:

290,for binary compounds containing nitrogen and boron and 400+ for binary compounds containing nitrogen and oxygen.
  
[List of Patents for class 423 subclass 407]    407Hydrazine or hydrazine hydrate
 This subclass is indented under subclass 406.  Products or processes in which the product is hydrazine (H2NNH2) or hydrazine hydrate (H2NNH2.H2O).

SEE OR SEARCH THIS CLASS, SUBCLASS:

388,for hydrazine sulfate (NH2NH2. H2SO4).
  
[List of Patents for class 423 subclass 408]    408Utilizing halogen or sulfur as reactant
 This subclass is indented under subclass 407.  Processes which include the use of a reactant containing sulfur or a halogen.
  
[List of Patents for class 423 subclass 409]    409Metal or ammonium containing
 This subclass is indented under subclass 406.  Products or processes in which the additional element is either a metal or the ammonium (NH4+) radical.
(1) Note. The ammonium (NH4+) radical is considered to be a single element, see (1) Note to the class definition.

SEE OR SEARCH CLASS:

148Metal Treatment,   subclasses 16.6 and 317+ for processes of making case hardened (nitrided) metals and the corresponding products, the intention being to form such case hardened metal, not to form a definite compound for recovery thereof, see reference to Class 148 in Line and Search Note Section of the Class Definition (423).
  
[List of Patents for class 423 subclass 410]    410Azide
 This subclass is indented under subclass 409.  Products or processes wherein the product includes the azide radical (-N3), with the metal or ammonium.
  
[List of Patents for class 423 subclass 411]    411Titanium or zirconium containing
 This subclass is indented under subclass 409.  Products or processes wherein the metal is titanium or zirconium.
  
[List of Patents for class 423 subclass 412]    412Aluminum containing
 This subclass is indented under subclass 409.  Products or processes wherein the metal is aluminum.
  
[List of Patents for class 423 subclass 413]    413Hydrogen containing (e.g., amide, imide, etc.)
 This subclass is indented under subclass 351.  Products or processes in which the product contains hydrogen.
(1) Note. Examples of compounds found in this subclass are: Amides (-NH2) and imides (-NH).
  
[List of Patents for class 423 subclass 414]    414CARBON OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products or processes in which the product is carbon or a compound thereof.

SEE OR SEARCH CLASS:

75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   subclasses 236+ for consolidated metal power compositions containing a carbide.
260Chemistry of Carbon Compounds,   for organic compounds and processes of making such compounds, meeting the structural requirements set out in the class definition thereof; see also (1) Note in subclass 226 of this class 423.
419Power Metallurgy Processes,   subclasses 14+ for processes of making articles from particulate material including a metal and a carbide compound comprising pressure and heat.
585Chemistry of Hydrocarbon,   appropriate subclasses for compounds containing carbon and hydrogen only, methods for their synthesis and purification, and certain compositions containing hydrocarbons.
588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing carbon, oxygen, sulfur, and metals.
  
[List of Patents for class 423 subclass 415.1]    415.1Oxygen containing:
 This subclass is indented under subclass 414.  Products or processes in which the product also contains oxygen.
  
[List of Patents for class 423 subclass 415.2]    415.2Percarbonate compound:
 This subclass is indented under subclass 415.1.  Products or processes wherein the compound has a percarbonate grouping; i.e., a (CO42-) radical.

SEE OR SEARCH THIS CLASS, SUBCLASS:

281,for processes of making perborates.
513,for processes of making persulfates.
584,for products and processes where the product is a peroxide.

SEE OR SEARCH CLASS:

252Compositions,   subclasses 181+ for bleaching agents.
  
[List of Patents for class 423 subclass 416]    416Carbonyl
 This subclass is indented under subclass 415.1.  Products or processes wherein the product contains the carbonyl group (CO) such as in iron penta carbonyl, Fe (CO)5, or carbonyl sulfide, COS.

SEE OR SEARCH CLASS:

260Chemistry of Carbon Compounds,   subclass 544 for carbonyl halide compounds or processes of making such compound.
  
[List of Patents for class 423 subclass 417]    417Metal containing
 This subclass is indented under subclass 416.  Products or processes wherein the product contains a metal in addition to the carbonyl group.
  
[List of Patents for class 423 subclass 418]    418Utilizing organic compound as reactant
 This subclass is indented under subclass 417.  Processes wherein at least one reactant is an organic chemical compound.
(1) Note. See (1) Note in subclass 226 for structural requirements of an organic compound.
  
[List of Patents for class 423 subclass 418.2]    418.2Carbon monoxide:
 This subclass is indented under subclass 415.1.  Products or processes wherein the product is carbon monoxide; i.e., CO.
  
[List of Patents for class 423 subclass 419.1]    419.1Carbonate or bicarbonate:
 This subclass is indented under subclass 415.1.  Products or processes wherein the product contains a carbonate (CO32-) or bicarbonate (HCO3-) radical.
(1) Note. A percarbonate may also be expressed as a carbonate in addition to a peroxide (e.g., Na2CO3 + H2O2); such compounds are assumed to have a percarbonate (CO42-) radical.

SEE OR SEARCH THIS CLASS, SUBCLASS:

105,for processes of treating mixtures to obtain a zinc (Zn), cadmium (Cd), or mercury (Hg) carbonate including (a) forming an insoluble substance in a liquid and (b) chemically forming a compound having the carbonate (CO32-) radical.
415.2,for products and processes wherein a compound has a percarbonate grouping.
  
[List of Patents for class 423 subclass 420]    420Ammonium containing
 This subclass is indented under subclass 419.1.  Products or processes wherein the carbonate contains the ammonium (NH4+) radical.

SEE OR SEARCH THIS CLASS, SUBCLASS:

237,for a process of preparing ammonium carbonate from ammonia in waste gas, the carbonate being recovered as a by-product, where the main intent is to purify the gas.
  
[List of Patents for class 423 subclass 420.2]    420.2Plural metal containing:
 This subclass is indented under subclass 419.1.  Products or processes wherein the carbonate product contains more than a single metal.
(1) Note. The plural metal of the carbonate compound may be multiple occurrences of the same metallic element in the compound.
  
[List of Patents for class 423 subclass 421]    421Alkali metal containing (Li, Na, K, Rb, or Cs)
 This subclass is indented under subclass 419.1.  Products or processes wherein the carbonate contains an alkali metal (lithium, sodium, potassium, rubidium or cesium).

SEE OR SEARCH THIS CLASS, SUBCLASS:

186,for processes of treating mixtures with a carbon containing compound to form an alkali metal carbonate or bicarbonate, including the step of forming an insoluble substance in a liquid.
  
[List of Patents for class 423 subclass 422]    422Hydrogen containing (bicarbonate)
 This subclass is indented under subclass 421.  Products or processes in which the radical contains hydrogen and is the bicarbonate (HCO3-) radical.
  
[List of Patents for class 423 subclass 423]    423By carbonating ammoniated brine
 This subclass is indented under subclass 422.  Processes which include the step of carbonating a solution of ammonia and a salt.
  
[List of Patents for class 423 subclass 424]    424By reacting halogen containing compound
 This subclass is indented under subclass 422.  Processes which include the step of reacting a compound that contains a halogen.
  
[List of Patents for class 423 subclass 425]    425Sesquicarbonate
 This subclass is indented under subclass 422.  Products or processes in which the product is a sesquicarbonate, i.e., a combination of a simple normal carbonate (e.g., Na2CO3) and simple bircarbonate (e.g., NaHCO3).
  
[List of Patents for class 423 subclass 426]    426Densifying soda ash
 This subclass is indented under subclass 421.  Processes which include the step of compacting or compressing soda ash (crude sodium carbonate).
  
[List of Patents for class 423 subclass 427]    427By reacting a bicarbonate
 This subclass is indented under subclass 421.  Processes which include the step of reacting a bicarbonate (HCO3-).
  
[List of Patents for class 423 subclass 428]    428By reacting sulfur containing compound
 This subclass is indented under subclass 421.  Processes which include the step of reacting a compound containing sulfur.
  
[List of Patents for class 423 subclass 429]    429By reacting halogen containing compound
 This subclass is indented under subclass 421.  Processes which include the step of reacting a compound containing a halogen.
  
[List of Patents for class 423 subclass 430]    430Alkaline earth metal containing (Mg, Ca, Sr, or Ba)
 This subclass is indented under subclass 419.1.  Products or processes wherein the carbonate contains magnesium, calcium, strontium or barium, i.e., the alkaline earth metals.

SEE OR SEARCH THIS CLASS, SUBCLASS:

165,for processes of treating mixtures to obtain alkaline earth metal carbonates.
  
[List of Patents for class 423 subclass 431]    431By reacting sulfur or halogen containing compound
 This subclass is indented under subclass 430.  Processes which include the step of reacting a compound that contains sulfur or a halogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

165,for processes of treating mixtures to obtain an alkaline earth metal carbonate, including the steps of (1) forming an insoluble substance in a liquid, and (2) chemically forming a carbonate having the CO32- radical.
  
[List of Patents for class 423 subclass 432]    432By reacting oxide or hydroxide of the metal
 This subclass is indented under subclass 430.  Processes which include the step of reacting an oxide or a hydroxide that contains the metal of the carbonate product.

SEE OR SEARCH THIS CLASS, SUBCLASS:

165,for processes of treating mixtures to obtain an alkaline earth metal carbonate including the steps of (1) forming an insoluble substance in a liquid, and (2) chemically forming a carbonate having the CO32-) radical.
  
[List of Patents for class 423 subclass 433]    433Lead containing
 This subclass is indented under subclass 419.1.  Products or processes wherein the carbonate contains lead.
  
[List of Patents for class 423 subclass 434]    434By reacting compound containing sulfur or a halogen
 This subclass is indented under subclass 433.  Processes which include the step of reacting a compound that contains sulfur or a halogen.
  
[List of Patents for class 423 subclass 435]    435By reacting lead acetate or acetic acid
 This subclass is indented under subclass 433.  Processes which include the step of reacting lead acetate or acetic acid.
  
[List of Patents for class 423 subclass 436]    436And utilizing metallic lead as reactant
 This subclass is indented under subclass 435.  Processes which also include the step of reacting elemental lead.
  
[List of Patents for class 423 subclass 437.1]    437.1Carbon dioxide or carbonic acid:
 This subclass is indented under subclass 415.1.  Products or processes wherein the product is carbon dioxide (CO2) or a solution thereof in water.
  
[List of Patents for class 423 subclass 437.2]    437.2From carbon monoxide:
 This subclass is indented under subclass 437.1.  Processes in which the product is made from carbon monoxide (CO).
  
[List of Patents for class 423 subclass 438]    438From a carbonate
 This subclass is indented under subclass 437.1.  Processes in which the product is made from a compound containing the carbonate (CO32-) or the bicarbonate (HCO3-) radical.
  
[List of Patents for class 423 subclass 439]    439Binary compound (e.g., carbide, etc.)
 This subclass is indented under subclass 414.  Products or processes wherein the product contains carbon and only one other element.

SEE OR SEARCH THIS CLASS, SUBCLASS:

345,for binary compounds which contain only carbon and silicon.
415.1,for carbon monoxide.

SEE OR SEARCH CLASS:

148Metal Treatment,   subclass 16.5 and 316+ for processes for making case hardened (carbided) metals and the corresponding products, the intention being to form such case hardened metal, not to form a definite compound for recovery; see reference to Class 148 in line and Search Note Section of the Class Definition.
  
[List of Patents for class 423 subclass 440]    440Refractory metal containing
 This subclass is indented under subclass 439.  Products or processes wherein the other element is chromium, molybdenum, tungsten, vanadium, niobium, tantalum, titanium, zirconium or hafnium, known as the refactory metals.
  
[List of Patents for class 423 subclass 441]    441Calcium containing
 This subclass is indented under subclass 439.  Products or processes wherein the other element is calcium.
  
[List of Patents for class 423 subclass 442]    442By reacting carbon and inorganic calcium containing compound
 This subclass is indented under subclass 441.  Processes which include the step of reacting carbon with an inorganic compound containing calcium.

SEE OR SEARCH THIS CLASS, SUBCLASS:

174,for processes of making calcium carbide from an impure calcium carbonate such as limestone.
  
[List of Patents for class 423 subclass 443]    443Disulfide
 This subclass is indented under subclass 439.  Products or processes wherein the binary compound is carbon disulfide.
  
[List of Patents for class 423 subclass 444]    444By reacting free carbon
 This subclass is indented under subclass 443.  Processes which include the step of reacting elemental carbon.
  
[List of Patents for class 423 subclass 445]    445Elemental carbon
 This subclass is indented under subclass 414.  Products or processes wherein the product is free carbon in substantially pure form.
(1) Note. See the note in the Class 264 class definition II. A. (10) for the line between Class 264 and Class 423 subclasses 445+ concerning combined processes of molding and carbonizing.

SEE OR SEARCH CLASS:

201Distillation: Processes, Thermolytic,   appropriate subclasses, for a process of making coke.
502Catalyst, Solid Sorbent, or Support Therefor: Product or Process of Making,   subclasses 174+ for compositions of and methods of making inorganic carbon containing catalyst or precursor therefor, subclasses 416+ for compositions of and methods of making solid sorbent compositions including elemental carbon.
516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   subclass 32 for colloid systems of colloid-sized solid or semisolid material which is primarily Carbon (such as graphite or diamond) dispersed in primarily organic continuous liquid phase, subclasses 38+ for colloid systems of colloid-sized bituminous, coal, or Carbon phase dispersed in aqueous continuous liquid phase, cross-reference art collection 901 for collection of art under the Class definition related to colloid systems of substantially pure elemental Carbon (such as graphite, diamond, Carbon black, lamp black, Fullerenes); or agents for such systems or making or stabilizing such systems or agents; in each instance, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
  
[List of Patents for class 423 subclass 446]    446Diamond
 This subclass is indented under subclass 445.  Products or processes wherein the product is carbon crystallized in the isometric form, usually in octahedral shape.

SEE OR SEARCH CLASS:

117Single-Crystal, Oriented-Crystal, and Epitaxy Growth Processes; Non-Coating Apparatus Therefor,   subclass 79 for processes for growing therein-defined single-crystal of diamond and subclass 929 for the art collection of carbon single-crystal references. Class 423, subclass 446, is a mandatory search and cross-reference for patents directed to forming a free-standing single-crystal diamond even though properly placed in Class 117 as an original.
264Plastic and Nonmetallic Article Shaping or Treating: Processes,   subclass 84 for the process of molding with a high pressure generated by an explosive force.
425Plastic Article or Earthenware Shaping or Treating: Apparatus,   subclass 1 for apparatus for molding with a high pressure generated by an explosive force; subclass 77 for making diamonds by applying ultra high pressure.
  
[List of Patents for class 423 subclass 447.1]    447.1Fiber, fabric, or textile
 This subclass is indented under subclass 445.  Products and processes ... wherein the product is substantially pure carbon in the form of a slender threadlike structure (fiber) a woven, knitted or fetted sheet material (fabric) or a woven fabric or cloth (textile).

SEE OR SEARCH CLASS:

8Bleaching and Dyeing; Fluid Treatment and Chemical Modification of Textiles and Fibers,   subclasses 115.51+ for processes and compositions for treating textiles and fibers to effect a chemical modification thereof, where the resulting product is other than an inorganic compound or element (e.g., carbon) as provided for in this class 423.
428Stock Material or Miscellaneous Articles,   subclass 367 for a carbon fiber structurally defined as provided for in the Class 428 definitions.
  
[List of Patents for class 423 subclass 447.2]    447.2Product
 This subclass is indented under subclass 447.1.  Products.
(1) Note. In order to be placed in this subclass as an original, a patent must contain a claim to an elemental carbon fiber, fabric or textile.
  
[List of Patents for class 423 subclass 447.3]    447.3From gaseous reactants
 This subclass is indented under subclass 447.1.  Processes wherein all the carbon forming reactant(s) are in the gaseous phase.
  
[List of Patents for class 423 subclass 447.4]    447.4Prior treatment before carbonization (except with gaseous oxygen)
 This subclass is indented under subclass 447.1.  Processes wherein prior to a reaction to convert a fiber, fabric or textile article to carbon, the article is treated with a substance other than gaseous oxygen which substance either (a) chemically reacts with the article or (b) is retained in the article at least until the commencement of a reaction to convert the article to carbon.
  
[List of Patents for class 423 subclass 447.5]    447.5With metal, metal compound, or phosphorus compound
 This subclass is indented under subclass 447.4.  Processes wherein the treating substance is a metal, a metal containing compound or a phosphorus containing compound.
  
[List of Patents for class 423 subclass 447.6]    447.6Including reaction with gaseous oxygen
 This subclass is indented under subclass 447.1.  Processes including a step of reaction with gaseous oxygen.
(1) Note. Heating in air is considered to be reaction with gaseous oxygen only when it is positively disclosed that such a reaction takes place.
  
[List of Patents for class 423 subclass 447.7]    447.7In specific atmosphere (other than vacuum or air)
 This subclass is indented under subclass 447.1.  Processes including a step of reaction in a specifically recited atmosphere other than vacuum or air.
  
[List of Patents for class 423 subclass 447.8]    447.8Controlling varying temperature or plural heating steps
 This subclass is indented under subclass 447.1.  Processes wherein a carbonizing reaction is carried out by (1) varying the temperature over a given time span or by (2) heating to two or more distinct temperatures.
(1) Note. Heating to cure binder or dry is not considered a carbonizing reaction without positive disclosure that carbonizing occurs under those conditions.
(2) Note. Heating a temperature to cause a change in crystalline form of the carbon (e.g., graphitizing) is considered a step of carbonizing for this subclass.
  
[List of Patents for class 423 subclass 447.9]    447.9Carbonizing cellulosic material
 This subclass is indented under subclass 447.1.  Processes wherein the material carbonized is natural cellulose or its derivatives (e.g., esters, ether, regenerated cellulose, etc.).
  
[List of Patents for class 423 subclass 448]    448Graphite
 This subclass is indented under subclass 445.  Products or processes wherein the product is graphite, which is the crystalline allotropic form of carbon, characterized by a hexagonal arrangement of the atoms.

SEE OR SEARCH THIS CLASS, SUBCLASS:

447,for a fiber, textile or fabric which is made of graphite.
  
[List of Patents for class 423 subclass 449.1]    449.1Carbon black (e.g., lampblack):
 This subclass is indented under subclass 445.  Products or processes wherein the product is a finely divided carbon particulate.

SEE OR SEARCH CLASS:

264Plastic and Nonmetallic Article Shaping or Treating: Processes,   subclass 84 for processes of molding with high pressure generated by an explosive force.
425Plastic Article or Earthenware Shaping or Treating: Apparatus,   subclass 77 for apparatus making diamonds by applying ultra high pressure.
  
[List of Patents for class 423 subclass 449.2]    449.2Treating carbon black:
 This subclass is indented under subclass 449.1.  Processes wherein carbon black is treated to change its characteristics.
  
[List of Patents for class 423 subclass 449.3]    449.3Treating with acid, or gas which forms an acid in water:
 This subclass is indented under subclass 449.2.  Processes wherein the carbon black material is treated with a compound that is an acid or with a gas that in an aqueous state would form an acid (e.g., H2S).
  
[List of Patents for class 423 subclass 449.4]    449.4Halogen or compound thereof:
 This subclass is indented under subclass 449.2.  Processes wherein the acid or the gas includes a halogen group element (e.g., HCl).
  
[List of Patents for class 423 subclass 449.5]    449.5Gaseous oxygen containing compound:
 This subclass is indented under subclass 449.2.  Processes wherein the treatment is with a gaseous compound including oxygen (e.g., CO).
  
[List of Patents for class 423 subclass 449.6]    449.6Utilizing synthetic polymer as reactant:
 This subclass is indented under subclass 449.1.  Processes wherein a compound that is a synthetic polymer (e.g., polyanylonitrite) is reacted or decomposed to form the product.
  
[List of Patents for class 423 subclass 449.7]    449.7Tire:
 This subclass is indented under subclass 449.6.  Processes wherein the polymer is obtained from tires or parts thereof.
(1) Note. Included in this subclass are polymeric material from scrap tires composed of compounds that include those produced by vulcanization of natural or synthetic rubber.
  
[List of Patents for class 423 subclass 449.8]    449.8Solid material in feed:
 This subclass is indented under subclass 449.1.  Processes which include feeding stock material that is in a solid-state, either homogeneous or heterogeneous (e.g., wood or coke).
  
[List of Patents for class 423 subclass 449.9]    449.9Liquid feed only:
 This subclass is indented under subclass 449.1.  Processes wherein initial feed stock is in a liquid state only.
  
[List of Patents for class 423 subclass 450]    450Directly from fluid hydrocarbon only
 This subclass is indented under subclass 449.1.  Processes wherein the carbon is made from the direct pyrolysis, cracking or decomposition of a compound containing only carbon and hydrogen (i.e., hydrocarbon) which is normally in the liquid or gaseous state.
(1) Note. Any "oil" or any "gas" (e.g., natural) is considered to qualify under this definition of hydrocarbon unless it is clear from the disclosure that an element other than carbon and hydrogen is present in the gas or oil. However, impurities in the fluid are disregarded if they are not the source for the carbon.

SEE OR SEARCH THIS CLASS, SUBCLASS:

449,for a process which uses a halogen containing compound, e.g., CHC13. as the feed stock for carbon black.
  
[List of Patents for class 423 subclass 451]    451Rapid and discontinuous oxidation
 This subclass is indented under subclass 450.  Processes wherein the carbon is formed from the hydrocarbon by rapid and discontinuous oxidation such as in an explosive reaction.
  
[List of Patents for class 423 subclass 452]    452Including flame impinging on cool surface
 This subclass is indented under subclass 450.  Processes wherein the carbon is deposited from a flame by causing the flame to directly contact a relatively cool surface.
  
[List of Patents for class 423 subclass 453]    453By contacting with catalyst or hot solid surface
 This subclass is indented under subclass 450.  Processes in which the decomposition takes place on contact between the hydrocarbon and (1) catalytic material or (2) a solid surface heated to a temperature at which the pyrolysis can occur.
  
[List of Patents for class 423 subclass 454]    454Hot particulate bed or reaction zone lining or refactory
 This subclass is indented under subclass 453.  Processes in which the contact is with a heated solid surface comprising particulate solids or the inner surface or firebrick of the zone in which the decomposition takes place.

SEE OR SEARCH THIS CLASS, SUBCLASS:

453,for a process of making carbon by contact of a fluid hydrocarbon with a liquid catalyst or a bed of unheated particulate solids.
  
[List of Patents for class 423 subclass 455]    455Specified injection velocity
 This subclass is indented under subclass 450.  Processes in which the speed of entry into the reaction zone of any feed material associated with the process is specifically stated.
(2) Note. The term "feed material" under this definition is not limited to the hydrocarbon being decomposed to result in the carbon; it also includes atomizing, heating, combustion or carrier gas, fuel, heat exchange medium, etc.
  
[List of Patents for class 423 subclass 456]    456Specified injection angle (e.g., helical, tangential, etc.)
 This subclass is indented under subclass 450.  Processes in which the angle of entry into the reaction zone of any feed material associated with the process is specifically stated.
(1) Note. The term "feed material" under this definition is not limited to the hydrocarbon being decomposed; it also includes any material associated in any manner with the process, e.g., atomizing, heating, combustion, or carrier gas, fuel, etc.
  
[List of Patents for class 423 subclass 457]    457At least one radial inlet
 This subclass is indented under subclass 456.  Processes in which at least one feed material enters the reaction zone in a direction which, if extended would intersect the longitudinal axis.
  
[List of Patents for class 423 subclass 458]    458Gas or vapor only as infeed to process
 This subclass is indented under subclass 450.  Processes in which the hydrocarbon feed consists of a fluid which is normally in the gas or vapor state.
(1) Note. A normal gas or vapor is considered to be a compound having between 1 and 4 carbons only.
(2) Note. Excluded under this definition is a process in which a liquid had been vaporized before entering the reaction zone. The initial starting material must be a normal gas or vapor for this subclass; if liquid, classification is in subclass 450.

SEE OR SEARCH THIS CLASS, SUBCLASS:

450,for a process in which the initial feedstock comprises a liquid, a mixture of gas and liquid or either gas or liquid, claimed generically as a fluid.
  
[List of Patents for class 423 subclass 459]    459From carbon monoxide infeed to process
 Processes under 449.1 wherein the carbon is made from carbon monoxide.
  
[List of Patents for class 423 subclass 460]    460Treating carbon
 This subclass is indented under subclass 445.  Processes wherein carbon in the elemental state is treated to change its characteristics.
  
[List of Patents for class 423 subclass 461]    461Recovery or purification
 This subclass is indented under subclass 445.  Processes wherein the carbon is separated from impurities.
  
[List of Patents for class 423 subclass 462]    462HALOGEN OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products or processes in which the product is a nonmetallic element of Group VII A of the periodic system having atomic numbers 9, 17, 35, or 53, or a compound thereof.

SEE OR SEARCH THIS CLASS, SUBCLASS:

249,for astatine (Atomic No. 85), which is the radioactive member of the halogens, and compounds thereof.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing halogens, oxygen, sulfur, and metals.
  
[List of Patents for class 423 subclass 463]    463Plural metal or metal and ammonium containing
 This subclass is indented under subclass 462.  Products or processes in which the product is a compound, which contains either (1) two or more diverse and distinct metal elements or (2) a metal and the ammonium (NH4+) radical.
  
[List of Patents for class 423 subclass 464]    464Including fluorine
 This subclass is indented under subclass 463.  Products and processes in which the halogen is fluorine.
  
[List of Patents for class 423 subclass 465]    465Including aluminum
 This subclass is indented under subclass 464.  Products or processes in which he product contains aluminum.

SEE OR SEARCH THIS CLASS, SUBCLASS:

116,for processes of treating mixtures to obtain a plural metal and halogen containing compound, wherein one of the metals is aluminum.
  
[List of Patents for class 423 subclass 466]    466Plural diverse halogens containing
 This subclass is indented under subclass 462.  Products or processes wherein the products includes two or more different halogens.
  
[List of Patents for class 423 subclass 467]    467Sulfur containing
 This subclass is indented under subclass 462.  Products or processes wherein the product contains sulfur.
  
[List of Patents for class 423 subclass 468]    468Ternary compound containing oxygen
 This subclass is indented under subclass 467.  Products or processes wherein the product is a ternary compound and contains only oxygen in addition to the sulfur and halogen.
  
[List of Patents for class 423 subclass 469]    469Binary compound
 This subclass is indented under subclass 467.  Products or processes wherein the product is a binary compound and contains only sulfur and a halogen.
  
[List of Patents for class 423 subclass 470]    470Ammonium halide
 This subclass is indented under subclass 462.  Products or processes wherein the product consists of the ammonium (NH4+) radical and a halogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:

462,for ammonium bifluoride (NH4F.HF).
  
[List of Patents for class 423 subclass 471]    471Recovery or purification
 This subclass is indented under subclass 470.  Products or processes in which the ammonium halide is obtained by separation or purification from a mixture (usually waste material).

SEE OR SEARCH THIS CLASS, SUBCLASS:

237,for a process of preparing an ammonium halide from the ammonia in waste gas where the main intent is to purify the gas, the halide being recovered as a by-product and the recovery being of secondary importance.
  
[List of Patents for class 423 subclass 472]    472Ternary compound
 This subclass is indented under subclass 462.  Products or processes wherein the product is a ternary compound and consists of two elements in addition to the halogen.
(1) Note. For purposes of this and indented subclasses, the ammonium radical is considered to be a single entity (element) and is classified as a ternary compound when combined with two other elements, but not as a hydrogen containing ternay compound; see also (1) Note in class definition.

SEE OR SEARCH THIS CLASS, SUBCLASS:

116,for processes of treating mixtures to obtain a ternary compound wherein two of the elements are metals and the third is a halogen, one of the metals being beryllium or a Group III A element.
  
[List of Patents for class 423 subclass 473]    473Hypohalite or hypohalous acid
 This subclass is indented under subclass 472.  Products or processes which consist of oxygen and a halogen as the (XO-) radical in combination with a third element.
  
[List of Patents for class 423 subclass 474]    474Calcium hypochlorite
 This subclass is indented under subclass 473.  Products or processes in which the compound is calcium hypochlorite (Ca (OC1)2).
  
[List of Patents for class 423 subclass 475]    475Halogenate (e.g., chlorates, etc.)
 This subclass is indented under subclass 472.  Products or processes which consist of oxygen and a halogen as the (XO3-) radical in combination with a third element.
  
[List of Patents for class 423 subclass 476]    476Perhalate or perhalic acid
 This subclass is indented under subclass 472.  Products or processes which consist of oxygen and a halogen as the (XO4-) radical in combination with a third element.
  
[List of Patents for class 423 subclass 477]    477Chlorine dioxide
 This subclass is indented under subclass 462.  Products or processes wherein the compound is chlorine dioxide (C1O2).
  
[List of Patents for class 423 subclass 478]    478By reacting a chlorate
 This subclass is indented under subclass 477.  Processes which include reacting a compound having the chlorate radical (C1O3-).
  
[List of Patents for class 423 subclass 479]    479And a nitrogenous or carbonaceous compound
 This subclass is indented under subclass 478.  Processes wherein the chlorate is reacted with a compound containing either nitrogen or carbon.
  
[List of Patents for class 423 subclass 480]    480And sulfur dioxide
 This subclass is indented under subclass 478.  Processes wherein the chlorate is reacted with sulfur dioxide (SO2).
  
[List of Patents for class 423 subclass 481]    481Hydrogen halide
 This subclass is indented under subclass 462.  Products or processes wherein the compound consists of hydrogen and a halogen.
  
[List of Patents for class 423 subclass 482]    482By reacting alkali metal salt with sulfuric acid
 This subclass is indented under subclass 481.  Processes in which include reacting an alkali metal and halogen containing salt with sulfuric acid.
  
[List of Patents for class 423 subclass 483]    483Hydrogen fluoride
 This subclass is indented under subclass 481.  Products or processes in which the halogen is fluorine.
  
[List of Patents for class 423 subclass 484]    484From impure starting material
 This subclass is indented under subclass 483.  Processes wherein the hydrogen fluoride is formed from an initial mixture containing an impurity.
  
[List of Patents for class 423 subclass 485]    485Fluorspar
 This subclass is indented under subclass 484.  Processes wherein the impure initial material is the mineral fluorspar (calcium fluoride, fluorite, CaF2).
  
[List of Patents for class 423 subclass 486]    486Utilizing an element as reactant
 This subclass is indented under subclass 481.  Processes wherein at least one of the reactants which forms the hydrogen halide is in elemental form.
  
[List of Patents for class 423 subclass 487]    487Reacting elemental hydrogen and elemental halogen
 This subclass is indented under subclass 486.  Processes wherein both the hydrogen and halogen are supported in the elemental form and are reacted with each other.
  
[List of Patents for class 423 subclass 488]    488Recovery or purification
 This subclass is indented under subclass 481.  Processes which include the step of removing an impurity either from the product or from the initial mixture, e.g., removing H2O, free halogen, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:

240+,for a process of removing impurities from a gaseous mixture having a halogen or a compound thereof as a constituent therein.
  
[List of Patents for class 423 subclass 489]    489Binary fluorine containing compound
 This subclass is indented under subclass 462.  Products or processes wherein the compound contains fluorine and only one other element.

SEE OR SEARCH THIS CLASS, SUBCLASS:

126,for processes of treating a mixture to obtain a binary fluorine containing compound, including the step of forming an insoluble substance in a liquid, and 483+ for a binary compound which contains fluorine and hydrogen.
  
[List of Patents for class 423 subclass 490]    490Alkali or alkaline earth metal containing
 This subclass is indented under subclass 489.  Products and processes in which the other element of the binary compound is lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium.

SEE OR SEARCH THIS CLASS, SUBCLASS:

185,for treating a mixture to obtain an alkali metal and fluorine containing compound by forming an insoluble substance in a liquid.
  
[List of Patents for class 423 subclass 491]    491Binary compound containing metal
 This subclass is indented under subclass 462.  Products or processes wherein the compound contains only a halogen and a metal.

SEE OR SEARCH THIS CLASS, SUBCLASS:

103,for processes of treating mixtures to obtain a Group II B metal halide including the steps of (1) forming an insoluble substance in a liquid and (2) chemically forming a halogen containing compound.
  
[List of Patents for class 423 subclass 492]    492Refractory metal (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, or W)
 This subclass is indented under subclass 491.  Products and processes in which the metal is of Group IV B, V B, or VI B, i.e., titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten, commonly known as the refractory metals.
  
[List of Patents for class 423 subclass 493]    493Iron group metal or copper (Fe, Co, Ni, or Cu)
 This subclass is indented under subclass 491.  Products or processes in which the metal is iron, cobalt, nickel or copper.
  
[List of Patents for class 423 subclass 494]    494Group IVA metal (Ge, Sn, or Pb)
 This subclass is indented under subclass 491.  Products or processes in which the metal is either germanium, tin or lead.

SEE OR SEARCH THIS CLASS, SUBCLASS:

90,for a process of forming salts of tin wherein the intent is to recover a tin compound by destining a mixture thereof.
  
[List of Patents for class 423 subclass 495]    495Group IIIA metal or beryllium (Al, Ga, In, Tl, or Be)
 This subclass is indented under subclass 491.  Products or processes in which the metal is aluminum, gallium, indium, thallium or beryllium.

SEE OR SEARCH THIS CLASS, SUBCLASS:

126,for processes of treating a mixture to obtain a metal containing compound, wherein the metal is beryllium or a Group III A metal, including the steps of (1) forming an insoluble substance in a liquid and (2) chemically forming a halogen containing compound.
130,for the process of recovering aluminum chloride catalysts from hydrocarbon waste materials by destroying or separating from the hydrocarbon.
135+,for the process of recovering aluminum halides by volatization.
  
[List of Patents for class 423 subclass 496]    496Utilizing carbon or carbon containing compound
 This subclass is indented under subclass 495.  Processes in which the compound is made by utilizing carbon or a compound thereof in a reaction.

SEE OR SEARCH THIS CLASS, SUBCLASS:

135+,for the process of recovering aluminum halides by volatization wherein carbon or a carbon containing compound maybe utilized.
  
[List of Patents for class 423 subclass 497]    497Alkaline earth metal (Mg, Ca, Sr, or Ba)
 This subclass is indented under subclass 491.  Products or processes in which the metal is magnesium, calcium, strontium or barium.

SEE OR SEARCH THIS CLASS, SUBCLASS:

163,for processes of treating mixtures to obtain a compound containing a halogen and an alkaline earth metal, including the steps of (1) forming an insoluble substance in a liquid and (2) chemically forming a halogen containing compound.
490,for a binary compound consisting of fluorine and an alkali or alkaline earth metal.
  
[List of Patents for class 423 subclass 498]    498Anhydrous magnesium chloride
 This subclass is indented under subclass 497.  Products or processes wherein the compound is anhydrous magnesium chloride.
  
[List of Patents for class 423 subclass 499.1]    499.1Alkali metal:
 This subclass is indented under subclass 491.  Products or processes wherein the metal is an alkali metal (i.e., lithium, sodium, potassium, rubidium, or cesium).

SEE OR SEARCH THIS CLASS, SUBCLASS:

197,for treating mixtures to form an alkali metal and halogen containing compound by forming an insoluble substance in a liquid.
490,for a binary compound containing an alkali metal and fluorine.
  
[List of Patents for class 423 subclass 499.2]    499.2From carbonaceous compound:
 This subclass is indented under subclass 499.1.  Products or processes wherein the alkali metal is obtained from carbon containing compound.
  
[List of Patents for class 423 subclass 499.3]    499.3Lithium chloride:
 This subclass is indented under subclass 499.1.  Products and processes wherein the product is lithium chloride (i.e., LiCl).
  
[List of Patents for class 423 subclass 499.4]    499.4Sodium chloride:
 This subclass is indented under subclass 499.1.  Products and processes wherein the product is sodium chloride (i.e., NaCl).
  
[List of Patents for class 423 subclass 499.5]    499.5Purification:
 This subclass is indented under subclass 499.4.  Products and processes wherein purified sodium chloride is obtained.
  
[List of Patents for class 423 subclass 500]    500Elemental halogen
 This subclass is indented under subclass 462.  Products or processes wherein the product is a halogen in elemental form.

SEE OR SEARCH THIS CLASS, SUBCLASS:

249,for astatine (Atomic No. 85), which is the radioactive member of the halogen family, or a compound thereof.
  
[List of Patents for class 423 subclass 501]    501Ion exchanging or liquid-liquid extracting
 This subclass is indented under subclass 500.  Processes which includes the step of solvent-solvent extraction or ion exchange; see Glossary.
  
[List of Patents for class 423 subclass 502]    502Oxidizing catalytically
 This subclass is indented under subclass 500.  Processes which include the step of oxidation in the presence of a catalyst.
  
[List of Patents for class 423 subclass 503]    503Sorbing
 This subclass is indented under subclass 500.  Processes which include the use of a sorbent; see Glossary.
  
[List of Patents for class 423 subclass 504]    504From mixture containing alkali metal or alkaline earth metal
 This subclass is indented under subclass 500.  Processes wherein the elemental halogen is derived from an initial mixture which contains lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium.
  
[List of Patents for class 423 subclass 505]    505Forming insoluble substance in liquid
 This subclass is indented under subclass 504.  Processes wherein a substance is formed in a liquid or slurry, which substance is insoluble therein and can be or is separated from the liquid and the other materials which remain soluble in the liquid; or wherein the composition of the liquid is changed so that one part of the mixture becomes insoluble therein.
  
[List of Patents for class 423 subclass 506]    506By reacting alkali metal halide with sulfur compound
 This subclass is indented under subclass 500.  Processes which include the step of reacting a compound of sulfur with the halide of lithium, sodium, potassium, cesium or rubidium.
  
[List of Patents for class 423 subclass 507]    507By reacting hydrogen halide or ammonium halide
 This subclass is indented under subclass 500.  Processes in which a hydrogen halide or an ammonium halide is utilized as a reactant.

SEE OR SEARCH THIS CLASS, SUBCLASS:

502,for a process of preparing elemental halogen by catalytically reacting the hydrogen or ammonium halide.
  
[List of Patents for class 423 subclass 508]    508SELENIUM OR TELLURIUM OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products and processes wherein the product is either selenium or tellurium, or a compound thereof.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing Se or Te.
  
[List of Patents for class 423 subclass 509]    509Binary compound
 This subclass is indented under subclass 508.  Products and processes wherein the product is a binary compound which contains only one element in addition to the selenium or tellurium.
  
[List of Patents for class 423 subclass 510]    510Elemental selenium or tellurium
 This subclass is indented under subclass 508.  Products and processes wherein the product is elemental selenium or tellurium.
  
[List of Patents for class 423 subclass 511]    511SULFUR OR COMPOUND THEREOF
 This subclass is indented under the class definition.  Products or processes wherein the product is sulfur or a compound thereof.

SEE OR SEARCH CLASS:

588Hazardous or Toxic Waste Destruction or Containment,   subclasses 300 through 415and 249-260 for the destruction or containment of hazardous or toxic waste containing sulfur, halogen, nitrogen, and metals.
  
[List of Patents for class 423 subclass 512.1]    512.1Oxygen containing:
 This subclass is indented under subclass 511.  Products or processes wherein the product also contains oxygen.
  
[List of Patents for class 423 subclass 513]    513Persulfate
 This subclass is indented under subclass 512.1.  Products or processes wherein the product contains the peroxymonsulfate (SO52-) or the peroxydisulfate (S2O82-) radical.
(1) Note. These radicals may also be identified as the permonosulfate or the perdisulfate, respectively.
  
[List of Patents for class 423 subclass 514]    514Thiosulfate
 This subclass is indented under subclass 512.1.  Products or processes wherein the compound contains the thiosulfate radical (S2O32-).
  
[List of Patents for class 423 subclass 515]    515Dithionite
 This subclass is indented under subclass 512.1.  Products or processes wherein the product is a dithionite having the radical (S2O42-).
(1) Note. Dithionite is frequently incorrectly termed hydrosulfite in the patents.
(2) Note. The term hyposulfite is generic to both dithionite and thiosulfate.
  
[List of Patents for class 423 subclass 516]    516Employing amalgam as reactant
 This subclass is indented under subclass 515.  Processes wherein an alloy of mercury is employed as a reactant in the process of forming a dithionite.
  
[List of Patents for class 423 subclass 517]    517Metal and ammonium containing
 This subclass is indented under subclass 512.1.  Products or processes wherein the compound also contains both a metal and the ammonium (NH4+) radical in addition to sulfur and oxygen.
(1) Note. Examples of the compounds included in this subclass are K NH4 SO4, (NH4)2 H2ZrO(SO4)3 and 5 K2SO4 (NH4)2SO4.
(2) Note. Many of the ammonium and metal containing compounds belong to the class known as alums which are double salts of the general formula M"M" (SO4)2. 12H2O) where M" may be certain univalent cations (e.g., Na, K, NH4+, Li, Ag, etc.) and M""" may be certain trivalent cations (e.g., A1, Ga, Ti, Fe, Cr, etc.).

SEE OR SEARCH THIS CLASS, SUBCLASS:

114,for recovery of compounds containing ammonium and aluminum where the starting material is a mixture or an ore.
  
[List of Patents for class 423 subclass 518]    518Plural metal containing
 This subclass is indented under subclass 512.1.  Products or processes , wherein the compound contains two or more different metals in addition to sulfur and oxygen.
(1) Note. Examples of the compounds included in this subclass are K2SO4A12 (SO4)3 24 H2O, Na2A12 (SO4)4, and PbS BaO.
(2) Note. Many of the plural metal containing compounds are known as alums, see (2) Note in subclass 517 for description of these compounds.

SEE OR SEARCH THIS CLASS, SUBCLASS:

117,for processes of treating mixtures to obtain a plural metal compound containing both oxygen and sulfur.
  
[List of Patents for class 423 subclass 519]    519Bisulfite
 This subclass is indented under subclass 512.1.  Products or processes wherein the compound contains the bisulfite or acid sulfite radical (HSO3-).
  
[List of Patents for class 423 subclass 519.2]    519.2Sulfite:
 This subclass is indented under subclass 512.1.  Products and processes wherein the compound is a sulfite; i.e., includes a (SO32-) radical.
  
[List of Patents for class 423 subclass 520]    520Bisulfate
 This subclass is indented under subclass 512.1.  Products or processes wherein the compound contains the bisulfate or acid sulfate radical (SO42-).