EXTRACTION OF ZINC AND CADMIUM BY TRI-N-BUTYL PHOSPHATE FROM AQUEOUS CHLORIDE SOLUTIONS

Studies have been made on the extraction of zinc and cadmium by TBP (tri-n-butyl phosphate) from aqueous solutions of calcium and sodium chloride. The separation of Zn from Cd is increased by dilution of the TBP to 50 per cent with kerosene and decreased by an increase in the extracted metal ion concentration. The species extracted from neutral solutions of CaCl2 and NaCl appear to be predominantly ZnCl2, 3TBP and CdCl2, 2TBP. In dilute acid solutions, acido-complexes of the type HMCl3 are also extracted, and there is evidence for the extraction of H2CdCl4 at >0·5. M HCl in NaCl and CaCl2 solutions. © 1969.