METHOD OF PREPARING ZIRCONIUM FLUORIDE COMPOUNDS HAVING LOWER HAFNIUM CONTENT Russian patent published in 2001 - IPC

FIELD: preparation of pure potassium fluorozirconate. SUBSTANCE: zirconium concentrate is stripped with nitric acid. Zirconium and hafnium are separated by extraction. The resulting zirconium solution is evaporated till crystals of mixture of zirconium nitrate and oxynitrate are isolated. The filtered crystals are treated with potassium fluoride and acid at pH of 3.0-5.0 at 70-95 C. KF/Hf molar ratio is not less than 5. Potassium fluoride is spent electrolyte or carbonate solution resulting from electrolytic preparation of zirconium powder. Acid is mixture of HF and HCl or HCl or HF. EFFECT: lower manufacturing cost intensified process, preparation of product. 2 cl, 3 ex, 1 tbl