A review on the aqueous chemistry of Zr(IV) and Hf(IV) and their separation by solvent extraction

Solvent extraction systems for the separation of zirconium(IV) and hafnium(IV) from different aqueous media, such as sulfate, chloride and nitrate were reviewed. The important parameters like extraction efficiency, extraction reaction, separation selectivity and separation factor were discussed in the light of the complex formation of the two metals and the nature of extractants. The studies showed the possibility for the separation of zirconium and hafnium from different aqueous solutions using single anionic, cationic, solvating extractants and extractant mixtures. The comparisons and summaries presented in this review may guide the future direction for the solvent extraction separation of zirconium and hafnium.

Graphical abstractIllustration of the extraction and separation behaviors of Zr(IV) and Hf(IV) in HCl, HNO3 and H2SO4 solutions with different kinds of extractants.Figure optionsDownload full-size imageDownload as PowerPoint slide