The influence of the treatment of Zr(IV) and Hf(IV) sulfate solution on the ion-exchange purifying of zirconium from hafnium on Diphonix® resin

The tendency of Zr(IV) and Hf(IV) to form polynuclear species (especially mixed Zr–O–Hf complexes) in aqueous solutions is, besides their almost identical chemical properties, one of the main obstacles in their separation. Therefore, finding a suitable way for the aforementioned complexes to decompose may play a crucial role in efficiently purifying zirconium from hafnium. The best purifying efficiency on Diphonix® resin was obtained with a zirconium sulfate solution prepared with the intermediate stage of fluoride complexes creation. This permits the collection of the purest fraction of the zirconium sulfate solution, which has a hafnium content ten times lower than in the case of typically prepared solutions.