Abstract: The efficient recycling of the spent lithium-ion batteries is of great significance for protecting the environment and promoting the sustainable development of the new energy industry. In view of the problems such as high recovery cost and waste gas emissions in the existing combined process, this study proposes a new method for selective lithium extraction from lithium cobaltate cathode material through thermite reduction roasting followed by lime leaching. The thermodynamic analysis of the thermite reduction process of lithium cobaltate is conducted using HSC Chemistry software to determine the feasible reaction path. Subsequently, the influence laws of roasting temperature and the dosage of reducing agent on selective lithium extraction and the phase composition of the roasted product are systematically investigated, and the effects of leaching temperature, leaching time, and the dosage of calcium oxide on selective lithium extraction efficiency are further studied. The roasted products and leaching residues are characterized by techniques such as XRD, SEM-EDS, and XPS. The research results show that the thermite reduction reaction of lithium cobaltate is thermodynamically feasible. Under the optimal roasting conditions of a roasting temperature of 650℃ and an aluminum powder dosage of 25wt%, LiCoO2 is efficiently dissociated and transformed into LiAlO2 and CoO. Subsequently, under the optimal leaching conditions of a leaching temperature of 70℃, a leaching time of 1.0 h, and a calcium oxide dosage twice the theoretical amount, 94.7% of Li can be selectively and efficiently leached. This innovative method exhibits distinct advantages over conventional processes, including zero exhaust gas emissions during thermal treatment, shortened recovery process, low operational costs, and high recovery efficiency of valuable metals. The proposed technique can provide an environmentally friendly and economically feasible solution for the short-process and low-carbon recovery of lithium from spent lithium-ion batteries, and offer a new idea for the sustainable utilization of secondary resources.

Key words: lithium cobaltate battery, aluminum thermite reduction, lime leaching, selective lithium extraction

摘要： 失效锂离子电池的高效循环利用对生态环境保护与新能源产业的可持续发展具有重要意义。针对现有联合回收工艺存在成本高、易产出废气等问题，本研究提出钴酸锂正极材料铝热还原焙烧-石灰浸出的选择性提锂新方法。采用HSC Chemistry软件对钴酸锂的铝热还原过程进行热力学分析，确定了可行的反应路径。随后，系统考察了焙烧温度和还原剂用量对选择性提锂及产物物相组成的影响规律，同时研究了浸出温度、时间和氧化钙用量对选择性提锂效果的影响，并通过XRD, SEM-EDS, XPS等技术对焙烧产物和浸出渣进行表征。结果表明，钴酸锂铝热还原反应在热力学上具有可行性；在焙烧温度650℃、铝粉用量25wt%的最优焙烧条件下，LiCoO2高效解离并转化为LiAlO2和CoO；后续在浸出温度70℃、浸出时间1.0 h、氧化钙用量为理论用量2倍的最优浸出条件下，94.7%的Li实现选择性高效浸出。与传统方法相比，该方法具有热处理过程无废气产生、回收流程短、成本低、有价金属回收率高等明显优势。该方法可为失效锂电池中锂元素的短流程、低碳回收提供一种环保且经济可行的解决方案，为二次资源的可持续利用提供新思路。

关键词: 钴酸锂电池, 铝热还原, 石灰浸出, 选择性提锂