关键词: zinc;cadmium;solvent extraction;thiophosphoric acid

Abstract: The extraction of cadmium and zinc with di-(2-ethylhexyl)-dithiophosphoric acid (D2EHDTPA)
-toluene and D2EHDTPA-triocty amine (TOA)-toluene has been investigated. Infrared spectrum
analysis, the nuclear magnetic resonance spectrum (NMR) analysis and conductivity
measurements confirm that the probable structures of the extracted complexes are CdA2 and
ZnA2. Cadmium can be extracted by D2EHDTPA very easily. Almost all the cadmium can be
extracted, but stripping of cadmium from the organic phase is very difficult. When a
mixture of D2EHDTPA and TOA is used, selective extraction of cadmium from zinc sulfate
solution can be achieved. Cadmium can be easily stripped from the organic phase.

Key words: zinc, cadmium, solvent extraction, thiophosphoric acid