US 11,701,600 B2
Method for crystallization of β-ammonium tetramolybdate
Jiangtao Li, Changsha (CN); Zhongwei Zhao, Changsha (CN); Zhichao Li, Changsha (CN); Xingyu Chen, Changsha (CN); Xuheng Liu, Changsha (CN); Lihua He, Changsha (CN); Fenglong Sun, Changsha (CN); Yongjin Luo, Changsha (CN); and Muye Cui, Changsha (CN)
Assigned to CENTRAL SOUTH UNIVERSITY, Changsha (CN)
Filed by CENTRAL SOUTH UNIVERSITY, Changsha (CN)
Filed on Nov. 23, 2022, as Appl. No. 17/992,949.
Claims priority of application No. 202111396089.4 (CN), filed on Nov. 23, 2021.
Prior Publication US 2023/0158424 A1, May 25, 2023
Int. Cl. B01D 9/00 (2006.01); C01G 39/00 (2006.01)
CPC B01D 9/0063 (2013.01) [B01D 9/005 (2013.01); C01G 39/006 (2013.01); B01D 2009/0086 (2013.01); C01P 2002/72 (2013.01); C01P 2004/03 (2013.01)] 20 Claims
 
1. A method for a crystallization of β-ammonium tetramolybdate, comprising: performing a stepwise pH-adjusting treatment of an ammonium molybdate solution via zoning, wherein upon feeding the ammonium molybdate solution into a reaction system from a first zone, pH1 of a resultant solution in the first zone is adjusted to 7.0-6.0, prior to discharge into a second zone; pH2 of a resultant solution in the second zone is adjusted to be less than 6 and greater than or equal to 4, prior to discharge into a third zone; pH3 of a resultant solution in the third zone is adjusted to be less than 4 and greater than or equal to 2.5, prior to discharge into a fourth zone; pH4 of a crystallized slurry in the fourth zone is adjusted to be less than 2.5 and greater than or equal to 1, prior to discharge into a fifth zone; pH5 of a crystallized slurry in the fifth zone is adjusted to 2.5-4.0, prior to discharge into a sixth zone; and pH6 of a crystallized slurry in the sixth zone is adjusted to be less than 2.5 and greater than or equal to 2.0, prior to reflux of a portion of the crystallized slurry in the sixth zone to the third zone, with a remaining of the crystallized slurry in the sixth zone being fed into a product zone for a solid-liquid separation, to obtain the β-ammonium tetramolybdate.