Highly efficient and selective solvent extraction of zirconium and hafnium from chloride acid solution including amic acid extractant

Nuclear-grade zirconium (Zr) and hafnium (Hf) play an inevitably strategic role in the sustainable development of the nuclear industry. However, the efficient separation of Zr ions and Hf ions is still problematic due to their approximate ionic radii. This work, provides a novel strategy for separating Zr ions and Hf ions by solvent extraction using an HCl solution containing the green amic acid N, N-di-2-ethylhexyl diglycolamic acid (D2EHDGAA). The results demonstrated that D2EHDGAA in HCl solution presented excellent separation performance for Zr ions and Hf ions. The separation factor (βZr/Hf) in the simulation liquid was 11.4, and that in the zirconium oxychloride hydrolysate was 34.5 at an HCl concentration of 2.5 mol/L. In addition, the slope method shows that the concentration of Cl- in the feeding water phase plays a controlling role in the separation of Zr ions and Hf ions. Compared with HCl, HNO3 and ultrapure water, stripping can reach 94.3% at a H2SO4 concentration of 0.1 mol/L. Hopefully, the new environmentally friendly D2EHDGAA-HCl system can match the methyl isobutyl ketone (MIBK)-HSCN system for efficient and selective extraction of Zr and Hf ions and show optimistic application prospects in industry.