Solvent extraction of zirconium(IV) from acidic chloride solutions using 2-ethyl hexyl phosphonic acid mono-2-ethyl hexyl ester (PC-88A)

Solvent extraction of Zr(IV) from acidic chloride solutions has been carried out with 2-ethyl hexyl phosphonic acid mono-2-ethyl hexyl ester (PC-88A) as the extractant. Higher acid concentration increases the extraction of zirconium and is quantitative around 1 M HCl. An increase of extractant and Cl− concentration at constant H+ ion also increases the extraction of Zr(IV). Plots of log D vs. log [Cl−]/or [extractant] are linear with slopes ∼2 indicating the association of 2 mol of chloride ions and PC-88A with the extracted metal species. The IR spectra of the extracted Zr–PC-88A complex is reported. The effect of H+ ion concentration at constant concentration of [Cl−] has no effect on Zr(IV) extraction. Addition of sodium salts enhanced the extraction of Zr(IV) and follows the order NaSCN>NaNO3>Na2SO4>NaCl. Loading capacity of the 0.005 M PC-88A was determined to be 0.078 g L−1 Zr(IV). Stripping of metal from the loaded organic (LO) with different acids indicated sulphuric acid as the best stripping agent. Temperature, regeneration capacity of PC-88A, and extraction of associated elements such as Hf(IV), Ti(IV), Al(IV), and Fe(III) are also reported.