This study focused on the extraction of valuable metals from the cathode-active materials in spent lithium-ion batteries using a high-concentration chloride solution. The effects of the concentrations of ammonium chloride (NH4Cl), hydrochloric acid (HCl), and reductants such as hydrogen peroxide (H2O2) and urea (CO(NH2)2) on metal extraction and chlorine production were studied experimentally. The leaching mechanism was analyzed, and a leaching model was established. It was found that the addition of solid NH4Cl to an HCl solution significantly improved the metal extraction capability of the latter and reduced the formation of chlorine gas by 96.0% compared to that only using HCl. The activation energies for leaching Li, Ni, Co, and Mn were determined to be 30.4, 38.5, 30.6, and 38.2 kJ·mol−1, respectively. This study demonstrates an environmentally friendly method for recycling metal resources from cathode-active materials and furthers understanding of how NH4Cl inhibits chlorine production when leaching with mixed solutions of HCl and NH4Cl.

中文翻译：

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使用高浓度氯化物溶液从废锂离子电池的阴极活性材料中浸出有价值的金属

这项研究的重点是使用高浓度氯化物溶液从废旧锂离子电池的阴极活性材料中提取有价值的金属。实验研究了氯化铵 (NH4Cl)、盐酸 (HCl) 和过氧化氢 (H2O2) 和尿素 (CO(NH2)2) 等还原剂的浓度对金属萃取和氯生产的影响。分析了浸出机理，建立了浸出模型。结果表明，与仅使用 HCl 相比，将固体 NH4Cl 添加到 HCl 溶液中显着提高了后者的金属提取能力，并减少了 96.0% 的氯气形成。浸出 Li、Ni、Co 和 Mn 的活化能分别确定为 30.4、38.5、30.6 和 38.2 kJ·mol-1。