A separation–recovery method was proposed in this study to recover valuable elements from spent copper–indium–gallium–selenium (CIGS) materials based on the different physical and chemical properties of their components. Spent CIGS materials were first roasted at 1000 °C to achieve phase transformation. During the transformation, 99.9% selenium was volatilized and recovered via oxidation into selenium dioxide. Meanwhile, other metals were converted from selenides to oxides. Subsequently, the indium and gallium in the roasting product were separated from copper via sulfuric acid leaching and precipitation. After the precipitation product was roasted, mixed oxides that contained 90.59% indium oxide and gallium oxide were obtained. The recovery rates of indium and gallium were 97.74% and 97.41%, respectively. Lastly, 99.83% of the copper in the filtrate was recovered via solvent extraction. The selective separation and recovery of valuable metals can be achieved through the rational utilization of the physical and chemical properties of elements in spent CIGS materials.

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Lithium and rubidium, as important alkali metals, have a wide range of applications in many fields because of their unique physical and chemical properties. This paper proposes a novel method for the extraction of lithium and rubidium from polylithionite. The process primarily involves alkaline leaching, solvent extraction of rubidium, lithium phosphate precipitation, and zeolite synthesis. Results of alkaline leaching experiments show that the leaching rates of lithium and rubidium are 96.43 and 97.50%, respectively, under a leaching temperature of 250 °C, an NaOH concentration of 600 g/L, a leaching duration of 3 h, and a liquid−solid ratio of 7:1 mL/g. Through solvent extraction, the extraction rate of rubidium can reach 99.5%. More than 93.96% of lithium can be recycled by adding phosphoric acid to prepare lithium phosphate. The obtained basic leaching residue is pretreated to synthesize zeolite, achieving reasonable utilization of the waste residue. The rational use of waste residue has added value to the process and promoted the sustainable use of resources.

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