Efficient separation and recovery of gallium and indium in spent CIGS materials

Spent copper indium gallium selenide (CIGS) materials are considered a viable resource for the recovery of Cu, In, Ga, and Se. The oxidative roasting-leaching-extraction separation scheme for the recovery of these valuable metals is proposed. Spent CIGS materials were first roasted to transform Cu, In, and Ga from selenides to oxides and volatilize Se. Hydrochloric acid was then used to leach the oxides. The optimum leaching conditions are as follows: acid concentration of 4 mol/L, temperature of 80 °C, leaching time of 3 h, and liquid–solid ratio of 10 mL/g. The leaching rates of Cu, In, and Ga were 99.98%, 93.40%, and 96.86%, respectively. Finally, In and Ga were sequentially extracted from the solution by P204. Through solvent extraction, the extraction rate of In can reach 99.92%, that of Ga can exceed 99.34%, and Cu is hardly extracted. Meanwhile, using hydrochloric acid as the stripping agent, the stripping rates of In and Ga were 99.90% and 99.93%, respectively. Results suggest that the efficient recovery and separation of Cu, In, and Ga in spent CIGS materials can be achieved.