Extraction of Co and Ni metals using emulsion liquid membrane and liquid-liquid extraction with Cyanex 272 as extractant

Abstract

Metals from spent lithium ion batteries are generally taken by using leaching method. However, the use of leaching method produces solutions containing a variety of metals, such as cobalt (Co) and nickel (Ni). The methods to separate Co and Ni metals from the leaching solution was done in this research by using emulsion liquid membrane extraction and liquid-liquid extraction. In the emulsion liquid membrane extraction, pH of aqueous phase solution (4-6) was varied and in the liquid-liquid extraction, pH of aqueous solution (2-8) and extractant concentration (0.6-1.2 M) were varied. Cyanex 272 is an acidic extractant that was used in this research and the extraction of Co and Ni metal take place through cation exchange mechanisms. In this research, the aqueous solution contains Co and Ni metals, both respectively 4533 mg/L and 945 mg/L. In emulsion liquid membrane extraction, the metals from aqueous solution was extracted using 0.7 M Cyanex 272 in kerosene solvent, 10% w/v SPAN 80 as surfactant and 0.1 M H2SO4 as stripping agent by varying the pH of the aquatic solution. The liquid-liquid extraction process was then employed by varying the pH of the aquatic solution and the extractant concentration in order to obtain optimum separation of Co and Ni metals. The optimum extraction of Co and Ni metals using emulsion liquid membrane was obtained at pH 6 with Co and Ni metals extracted 47.09% and 29.49%. While liquid-liquid extraction gave the optimum extraction at pH 4 with extractant concentration was 0.6 M with Co and Ni metals extracted 42.64% and 34.73%. The result of this research showed that liquid-liquid extraction gave more optimum separation of Co and Ni metals rather than the emulsion liquid membrane extraction.