Abstract: Studies have been made on the extraction of Zn and Cd by TBP(tri-n-butyl phosphate) from diluent hydrochloric acid solutions of soldium chloride.The experiments show that the species extracted from diluent HCI solutions of NaCl appear to be predominantly ZnCl_2· 2TBP and CdCl_2·2TBP.For Cd,at lower acidities,anionic complexes of the type H_2CdCl_3 are also extracted.As the acidity is increased,H_2CdCl_4 appear to be predominant complexes in organic phase.For Zn,the acidocomplexes of the type HZnCl_3 appear in organ- ic phase after the acidity of solutions reaching a certain value([HCl]>0.1 mol/L). Furthermore,the ultraviolet absorption spectra of both aqueous and organic phases have been studied,and the infrared spectra of the organic phases have been exomined.The extraction mechanism and temperature effect are also discussed.

Key words: extraction, solvent extraction, Zn, Cd, tri-n-butyl phosphate, zinc chloride