METHOD OF PREPARING CERIUM CONCENTRATE Russian patent published in 1999 - IPC

FIELD: chemical industry, more particularly, production of rare-earth elements fro hydroxide stock. SUBSTANCE: pulp of rare- earth element hydroxides is isothermally saturated with chlorine or bromine till they are completely dissolved in water. The resulting mixture is then heated at rate of 0.5-10 deg/min. As soon as pH of solution reaches 0.5-3, heating is discontinued. This makes it possible to simplify method. Addition of chlorides of corresponding metals to pulp of rare-earth element hydroxides at molar ratio of hydroxides to chlorides of 1:(0.3-1) reduces amount of chlorine essential for operation. According to above-mentioned methods, cerium recovery is more than 95%. Recovery of cerium with chlorine is carried out at excessive pressure of 5 atm. Recovery of cerium into precipitate increases to 98% or more and relative cerium content in concentrate increases to 89% or more. EFFECT: more efficient preparation method. 3 cl, 4 ex