Solvent extraction of hafnium from thiocyanic acid medium in DIBK-TBP mixed system

A novel process for the separation of hafnium from thiocyanic acid medium using the mixture of diisobutyl ketone (DIBK) and tributyl phosphate (TBP) as the extractant was developed. This extraction process was investigated experimentally as a function of the amount of TBP added, acidity, zirconium and hafnium concentrations, salting-out agent, temperature, duration, respectively. The results show that hafnium is enriched in the organic layer and zirconium is in aqueous layer in DIBK-TBP system. Under the optimal technological conditions: TBP addition 20% (v/v), aqueous phase acidity 3.0 mol/L, ammonium sulfate addition 0.8–1.25 mol/L, room temperature and extraction time 10 min, the separation factor of hafnium from zirconium is 9.3.