METHOD FOR PREPARING CALCIUM OXIDE Russian patent published in 2003 - IPC

FIELD: inorganic chemistry, chemical technology. SUBSTANCE: concentrate of isotope- -enriched calcium is dissolved in hydrochloric acid, solution is purified from impurities by precipitation of calcium oxalate in ammonia medium in the presence of tartaric acid, impurities of heavy metals are precipitated and separated as sulfides. From prepared solution calcium oxalate is precipitated repeatedly in ammonia medium in the presence of tartaric acid and calcium oxalate is dissolved in acid. Calcium carbonate is precipitated from purified solution with ammonia solution saturated with ammonium carbonate and calcium carbonate is separated and subjected for thermal treatment for two steps at 200-300 C and 800-850 C. Method for purification of calcium-containing concentrate provides rather complete separation of impurities and isolation of calcium without loss practically. Conditions for thermal treatment allows preparing the required chemical form of ready product. Proposed method provides isolation of 99.3% of isotope-enriched calcium as oxide with purification degree 99.96%. Method allows using standard equipment, available reagents being without significant consumption of electric energy. Method can be used for treatment of isotope-enriched calcium prepared by method of electromagnetic separation. EFFECT: improved preparing method, high yield and quality of product. 6 ex