Solvent Extraction of Zirconium and Hafnium as Homologues of Rutherfordium by Triisooctylamine from HCl Solutions

Abstract

Solvent extraction of the group 4 elements Zr and Hf, homologues of Rf (Z = 104), by triisooctylamine (TIOA) from hydrochloric acid (HCl) was performed by batch method using carrier-free radioisotope tracers. The times required to reach equilibria were determined, and then variations of the equilibrium distribution ratios (D) were investigated against the TIOA and HCl concentrations. It was found that the chemical reactions involved in the extraction of the chloride complexes of Zr and Hf by 0.1–1.0 M TIOA from 7.4–10.4 M HCl reached equilibrium in 10–20 min. The D values increased as the concentrations of HCl and TIOA increased, suggesting the formation of anionic chloride complexes of Zr and Hf. We obtained comparison data to study Rf-chloride complex formation. Although the reaction time in the extraction needs to be shortened, the extraction behavior of Rf could be investigated by solvent extraction under the present experimental conditions.