Patent ID: 7708962

Claim:
A process for separation of hafnium and zirconium from a mixture containing ZrCl 4 and HfCl 4 , the process comprising: introducing the mixture of ZrCl 4 and HfCl 4 in vapour form into a continuous extractive distillation column; selective absorption of the ZrCl 4 and HfCl 4 vapours by an extraction solvent circulating in a counter-current to a stream of the vapours in the distillation column; drawing-off of one of a liquid and gaseous mixture of ZrCl 4 and HfCl 4 enriched with ZrCl 4 ; drawing-off of one of a liquid and gaseous mixture of ZrCl 4 and HfCl 4 enriched with HfCl 4 ; hydrolysis of one of the mixture obtained in the step of drawing-off of one of a liquid and gaseous mixture of ZrCl 4 and HfCl 4 enriched with HfCl 4 in an aqueous solution of strong inorganic acid to form an aqueous solution having from 7 to 12 mol of acid per liter; passing the aqueous solution into an anion-exchange resin; and eluting and recovering a fraction enriched with hafnium.