Extraction and concentration of cobalt from acidic leach solutions containing Co–Ni by emulsion liquid membrane using TOA as extractant

The present investigation deals with carrier-facilitated membrane transport of cobalt from acidic leach solutions containing cobalt and nickel by emulsion liquid membrane (ELM). In this work, the zinc plant electrolyte purification was leached with hydrochloric acid and main acidic leach solution containing Zn(II), Cu(II), Fe(II), Cd(II), Co(II) and Ni(II) ions was obtained. After Zn(II), Cu(II), Fe(II) and Cd(II) ions in the acidic leach solution were separated, the important parameters influencing the extent of cobalt extraction were investigated and optimum conditions were determined. Cobalt transport was influenced by number of parameters like cobalt initial concentration, mixing speed, extractant concentration, surfactant concentration, the stripping solution type and concentration, and the feed solution acid concentration. After the optimum parameter values were determined, cobalt from the acidic leach solution containing 100 mg Co/L and 200 mg Ni/L was almost completely extracted within 10 min. The results showed that it is possible to extract 99% of cobalt by using ELM from the acidic leach solutions containing Zn(II), Cu(II), Fe(II), Cd(II), Co(II) and Ni(II) ions at the optimum operating conditions.