| Abstract:To address the high cost associated with the use of reducing agents such as H?O? in conventional hydrometallurgical recycling of spent lithium-ion batteries, this study employed a pulp and paper by-product, eucalyptus pre-hydrolysis liquor as a reducing agent in combination with sulfuric acid leaching to recover valuable metals (Li, Ni, Co, and Mn) from spent ternary lithium batteries. Xylan was used as a model compound to systematically investigate the effects of different leaching conditions on metal recovery, and the feasibility of using eucalyptus pre-hydrolysate as a practical reducing agent was further evaluated. The results showed that, under the optimized conditions of 2.5 mol/L sulfuric acid, 80% xylan dosage, 30 °C, a liquid-to-solid ratio of 25:1, and a reaction time of 1 h, the leaching efficiencies of Li, Ni, Co, and Mn all exceeded 95%. In addition, SEM, XRD, and XPS characterizations were employed to elucidate the reaction process by which xylan-assisted reduction and acid dissolution promoted the structural decomposition of cathode materials. This study demonstrates a circular strategy of “treating waste with waste” and provides a new pathway for the high-value utilization of papermaking by-products and the low-carbon of spent lithium-ion batteries. |