SYNERGISTIC EXTRACTION OF THE MIXTURE OF DI-(2-ETHYLHEXYL)-DITHIOPHOS-PHORIC ACID AND TERTIARY AMINE IN THE SEPARATION OF CADMIUM FROM ZINC

摘要

The extraction and separation of cadmium from zinc by di-( 2- ethylhexyl) -dithiophosphoric acid(D2EHDTPA) and by D2EHDTPD-tertiary amine(TOA) are investigated with toluene as diluent. Cadmium can be extracted very easily by D2EHDTPA. Almost all the cadmium was extracted, but stripping of cadmium from the loaded organic phase is very difficult. When the synergistic extraction system of D2EHDTPA-TOA is used, the selective extraction of cadmium from zinc sulfate solution can be achieved, and cadmium can be easily stripped from the organic phase. The interfacial reactions are the extraction rate determining steps.