Extraction and separation of Cd(II) and Ni(II) with salts of Cyanex 301 and amines

The extraction of cadmium from sulfuric acid solutions and its separation from nickel with salts of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) and amines was studied. The data obtained show that extractants based on Cyanex 301 and Quaternary ammonium bases are most suitable for this since it is possible to extract cadmium in the form of sulfates and bisulfates as well as stripping metal from the organic phase. For deep extraction of cadmium from sulfate solutions in this system, 1–2 stages of extraction are sufficient. At this stage, the separation coefficient of cadmium and nickel βCd/Ni reaches values > 106, and the distribution coefficient of cadmium reaches almost 104. Cadmium stripping is achieved by treating the organic phase with an ammonia solution containing ammonia more than 4 mol/L. The process can be used in the processing of cadmium–nickel batteries.