Solvent extraction separation of Zn(II), Fe(II), Fe(III) and Cd(II) using tributylphosphate and CYANEX 921 in kerosene from chloride medium

In this work, the extraction of Zn(II), Fe(II), Fe(III) and Cd(II) with tributylphosphate (TBP) and commercial trioctyl phosphine oxide (CYANEX 921) in kerosene from chloride medium has been studied. Different parameters affecting the extraction of the investigated metal ions such as hydrochloric acid, hydrogen ion, extractant, metal ion concentrations and temperature investigations were carried out. The stoichiometry of the extracted metal species investigated by TBP and CYANEX 921 were found to be HZnCl3 center dot 3TBP, HFeCl4 center dot 2TBP, H2CdCl4 center dot 3TBP, HZnCl3 center dot 2C921, HFeCl4 center dot C921 and H2CdCl4 center dot 3C921, respectively. The stripping of the extracted metal species by nitric, sulfuric and hydrochloric acids and distilled water were carried out. Based on the obtained results undiluted TBP was selected as a suitable extractant for the recovery of zinc from pickling solution resulting from hot dipping galvanizing bath. (C) 2007 Elsevier B.V. All rights reserved.