Solvent extraction of Hf(IV) from acidic chloride solutions using Cyanex 302

Studies on solvent extraction of Hf(IV) from acidic chloride solutions have been carried out using Cyanex 302 as the extractant diluted in kerosene. Variations of acid and extractant concentrations on the extraction of metal indicated decrease and increase in percentage extraction, respectively. Further, the plots of logD vs. log [HCl]/log [HA] gave negative and positive slopes of 2, indicating that the extraction follows ion exchange mechanism: MO2+(aq) + 2HA(org) ↔ MOA2(org) + 2H+(aq), where, M=Hf(IV); HA=Cyanex 302. Stripping of metal from the loaded organic (LO) with different acids indicated sulfuric acid as the best stripping agent. Increase of temperature during extraction stage increases the metal transfer showing exothermic nature of the extraction process. Regeneration and recycling capacity of Cyanex 302, extraction behavior of associated elements such as Zr(IV), Ti(IV), Al (III), Fe(III) and IR spectra of the extracted Hf–Cyanex 302 has been studied.