The selective recovery of cadmium(II) from sulfate solutions by a counter-current extraction–stripping process using a mixture of diisopropylsalicylic acid and Cyanex® 471X

The liquid–liquid extraction of cadmium(II) from solutions, obtained by leaching of deposited cadmium carbonate or cadmium cementation sponge and heavily contaminated with other components, especially zinc, has been studied. Initially the solutions were purified; iron and other contaminants were removed by oxyhydrolysis. An equimolar mixture of diisopropylsalicylic acid and Cyanex® 471X (0.5 mol/L/0.5 mol/L), diluted with Solvesso 150, was used as the solvent. Experiments were performed both, as a laboratory simulation of a counter-current system, and in continuous counter-current trials using mixer-settlers. Good separation of cadmium(II) and zinc(II) has been obtained.