Solvent extraction recovery and separation of cadmium and copper from sulphate solution

• The ability of a phosphoric acid (D2EHPA) and an oxime extractant (MEX) to recovery and separation of cadmium and copper was compared.
• Optimum condition for solvent extraction of each extractant for each metal was determined.
• It was found that MEX has better ability to separate copper over cadmium whereas D2EHPA is more suitable whenever coextraction of these metals concerns.

In this study solvent extraction process has been used for separation of cadmium and copper from sulphate solution. A phosphoric acid extractant (D2EHPA) and an oxime extractant (MEX) in kerosene diluent were used as cadmium and copper extractants, respectively. The results showed that 1 g/L cadmium could be extracted by 30–35% (v/v) D2EHPA at the pH of 3.5–4. Cadmium separation factor over copper with D2EHPA was calculated 4.04 in best condition of pH (=2). On the other hand 3% MEX separated 1 g/L copper over cadmium optimally at the pH of 3.5 and under this condition of pH, copper separation factor is calculated 4495.5. Loading capacity studies showed that copper existence in cadmium aqueous solution reduces cadmium extraction with D2EHPA up to 10% whilst copper extraction percentage with MEX does not vary considerably in the presence of cadmium.