METHOD OF RECOVERY OF CERIUM (+4) FROM NITRATE SOLUTION OF RARE-EARTH ELEMENTS Russian patent published in 2001 - IPC

FIELD: preparation of cerium compounds for production of catalysts and polishing powders. SUBSTANCE: water is added to solution of cerium (+4) and rare-earth elements. Water is used in amount that meets relationship: H orig. +3 [Cr(+4)]orig <(V add + V orig. / V orig <10 [(Ce+4)] orig wherein H orig, [Ce(+4)] orig. are numerical values of concentrations of free nitric acid and cerium in original solution expressed on mole/l; V orig and V add are numeral values of volumes of original solution and added water expressed in1. Cerium salt is deposited from the resulting solution at temperatures from 70 to 100 C for at least 30 minutes. EFFECT: selective recovery of cerium and reduced consumption of reactants. 1 ex, 1 tbl