METHOD OF EXTRACTION OF CERIUM FROM NITRATE SOLUTIONS CONTAINING SUM OF RARE-EARTH ELEMENTS Russian patent published in 2015 - IPC C01F17/00 

FIELD: metallurgy.

SUBSTANCE: invention can be used for processing of concentrates of rare-earth metals. For extraction of cerium from the nitrate solution containing the sum of rare-earth elements, cerium is oxidised to tetravalent state by hydrogen peroxide and is settled by ammonia by simultaneous their adding in separate portions at continuous stirring of pulp. The completeness of behaviour of reactions is monitored. The pulp is heated and filtered, deposit is washed out and the obtained cerium hydroxide is dried. Oxidation and sedimentation operations are conducted at the temperature of solution 40-50°C at pH 5.8-6.0. The pulp is heated up to the temperature 75-85°C and maintained at pH 5.8 within 30-60 minutes with the subsequent adding to the pulp of nitric acid up to pH value 4.5. Before filtration the pulp is conditioned for pH stabilisation. The obtained deposit of cerium hydroxide is washed out by distilled water using repulping-filtration method.

EFFECT: invention allows to the degree of extraction of cerium from solution and purity of cerium hydroxide at smaller number of operations.

4 cl, 3 tbl