CPC B22C 1/167 (2013.01) [B22C 1/02 (2013.01); B22C 1/183 (2013.01); B22C 1/2253 (2013.01); B22C 1/2273 (2013.01); B22C 9/088 (2013.01); C04B 35/6303 (2013.01); C04B 35/63404 (2013.01); C04B 35/63476 (2013.01); C04B 38/0061 (2013.01); C04B 38/085 (2013.01); C04B 2235/3427 (2013.01)] | 10 Claims |
1. A molding for the foundry industry, produced using
closed-pore microspheres of expanded perlite, having a closed foam structure with pores separated from one another, and wherein the microspheres are closed on their surface;
wherein the microspheres have a particle size d50 of 200 to 250 μm;
expanded glass;
wherein a weight ratio of perlite to expanded glass ranges from 1:1 to 1:2;
and an organic or inorganic binder or a mixture of organic and inorganic binder, wherein the binder is selected from the group consisting of water glass, phenol-formaldehyde resins, two-component systems comprising as reactants a polyisocyanate and a polyol component containing free hydroxyl groups (OH groups), and starch
wherein the closed-pore microspheres of expanded perlite have a bulk density from 200 to 500 kg/m3.
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