Simultaneous extraction and separation of cobalt and nickel from chloride solution through emulsion liquid membrane using Cyanex 301 as extractant

In the present work, emulsion liquid membrane (ELM) is investigated to select the suitable conditions for extraction of Co (II) ions from acidic chloride solutions using Cyanex 301 as extractant. The effects of extractant and surfactant concentrations, mixing speed, concentration and type of stripping solution, phase ratio, treatment ratio, and nature of diluent on the extraction rate were studies. Under the optimum conditions, extraction of cobalt in competition with nickel has been also studied for different feed mixture solution. Solvent extraction and stripping of cobalt and nickel in mixture was first carried out in order to have an idea about this extractant. Solvent extraction results show that almost 99% of cobalt and nickel are extracted with 0.1 M Cyanex 301 at pH above 2 within 2 min. However, Based on the stripping process, it was possible to separate cobalt and nickel at low acid concentration (0.5 M) with separation factor of 502. ELM results show that under the optimum conditions, the system is selective for cobalt than nickel, especially within the first minutes of all experiments.