METHOD OF PRODUCTION OF POTASSIUM HEXOFLUOROZIRCONATE PURIFIED FROM HAFNIUM Russian patent published in 2005 - IPC

FIELD: hydrometallurgy of zirconium and hafnium; methods of production of potassium hexafluorozirconate purified from hafnium.

SUBSTANCE: the invention is pertaining to the field of hydrometallurgy of zirconium and hafnium and may be used in production of potassium hexafluorozirconate. Zirconium, brazilite at presence of a potassium chloride is subjected to dissection of silicofluoride. Then conduct: a leaching of zirconium and hafnium from a fusion cake of water-soluble compounds at the temperature of up to 85°C; a settling and separation of a hot solution from non-soluble compounds; chilling of a solution; the countercurrent recrystallization of the separated crystals of potassium hexafluorozirconate with feeding during the last stages of the recrystallization of water or ammonium hexafluorozirconate solution with the share of zirconium - up to 10 g/l and withdrawal of hafnium -enriched mother liquors from the first stages of the recrystallization. Then follows extraction from the mother liquors of potassium hexafluorozirconate crystals for their returning to the first stages of the recrystallization. Then conduct settling of zirconium hydroxide from the solutions enriched with hafnium. The hafnium enriched mother liquors from the first stages of the recrystallization are fed to the leaching from the fusion cake of the zirconium and hafnium water-soluble compounds. The countercurrent recrystallization of the potassium hexafluorozirconate crystals conduct at each stage at a crystallization degree and the number of the parallel streams determined from a the ratio:(1-α)^-0.54 ≤ K_pur  ⁿ , where: K_pur -_{the factor of the salt purification from hafnium at the stage;α - hexafluorozirconate crystallization degree at the stage; n - the number of parallel currents of mother liquors. The technical result is decreased material inputs and increased effectiveness of separation of zirconium and hafnium by the method of the countercurrent recrystallization of their doubled potassium fluorides.}

EFFECT: the invention ensures decreased material inputs, increased effectiveness of separation of zirconium and hafnium by the method of the countercurrent recrystallization of their doubled potassium fluorides.

5 cl, 3 ex, 2 tbl