METHOD OF CLEANING MIXTURE OF ZIRCONIUM AND HAFNIUM TETRACHLORIDES FROM IMPURITIES Russian patent published in 2019 - IPC C01G25/04 C01G27/04 C01B9/02 

FIELD: chemistry.

SUBSTANCE: invention can be used as a first step for purifying impurities from a mixture of zirconium tetrachlorides and hafnium before further separation and obtaining pure individual products. Method of cleaning mixture of tetrachlorides of zirconium and hafnium from impurities involves a step for dissolving zirconium tetrachlorides and hafnium in a solvent of potassium chloraluminate at temperature of 280–350 °C to achieve concentration of tetrachlorides 25–55 g per 100 g of solution. Resulting solution is fed at controlled rate to evaporation stage at temperature of 430–550 °C. Evacuated zirconium and hafnium tetrachlorides formed during evaporation are discharged for rectification separation operation. Zirconium and hafnium tetrachloride depleted solution is returned from the evaporation stage to a dissolution operation. Method includes performing flow-controlled removal of solid residue of insoluble impurities with solution taken from operation of evaporation, and simultaneous introduction of solvent into solution before operation of evaporation in volume equal to volume of withdrawn solution. At that removal of solid residue of insoluble impurities is performed at achievement of mass concentration of solid sediment in solution of 0.1–1.0 %.

EFFECT: invention increases degree of purification of mixture of zirconium tetrachlorides and hafnium from soluble and insoluble impurities.

1 cl, 1 dwg, 1 tbl