Separation of hafnium from zirconium in hydrochloric acid solution with di(2-ethylhexyl)phosphoric acid by solvent extraction

The preparation of nuclear-grade zirconium and hafnium is very important for nuclear power. The separation of hafnium from zirconium in a hydrochloric acid solution by solvent extraction was investigated with di(2-ethylhexyl)phosphoric acid (D2EHPA). The effects of hydrochloric acid concentration, extractant concentration, diluents, and temperature on the distribution coefficient of hafnium and zirconium were studied. The species extracted were ZrOA(2)center dot 2HA and HfOA(2)center dot 2HA. In this process, the separation factors varied with different diluents and followed the order octane > hexane > toluene > chloroform. A high separation factor value of 4.16 was obtained under the conditions of a solution containing 0.05 mol/L HCl and 0.01 mol/L D2EHPA for the separation of hafnium from zirconium. The extraction reaction was endothermic.