Zhang Guangwen, Liu Zimeng, Yuan Xue, He Yaqun, Wei Neng, Wang Haifeng, Zhang Bo
School of Environment Science and Spatial Informatics, China University of Mining and Technology, No.1 Daxue Road, Xuzhou, Jiangsu 221116, China; Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, No.59 Qinglong Road, Mianyang, Sichuan 621010, China.
School of Environment Science and Spatial Informatics, China University of Mining and Technology, No.1 Daxue Road, Xuzhou, Jiangsu 221116, China.
J Hazard Mater. 2022 May 15;430:128374. doi: 10.1016/j.jhazmat.2022.128374. Epub 2022 Jan 29.
From the perspective of environmental protection and resource recovery, recycling of spent lithium-ion batteries is a meaningful process. In this study, the removal of organics, liberatioin of electrode material, and reduction of high valence transition metal, as the key points in recycling efficiency of valuable metals, have been firstly achieved simultaneously by low temperature heat treatment recycling process. Pyrolysis characteristics of organics, phase transition behavior of spent cathode material and the thermal reduction mechanism were evaluated in the meantime. Results demonstrate that organics can be removed and the liberation of electrode materials can be improved by pyrolysis. High-valence transition metals in cathode materials are synchronously reduced to CoO, NiO, MnO, Ni, and Co based on the reducing action of organics, aluminum foil and conductive additives. At the same time, Li element exists in the form of LiCO, LiF and aluminum-lithium compound that can be recycled by water-leaching in the water impact crushing process while transition metals can be recycled by acid leaching without reducing agents. 81.26% of Li can be recycled from water-leaching process while the comprehensive recovery rate of Ni, Co, Mn is 92.04%, 93.01%, 92.21%, respectively. This study may provide an environmentally-friendly recycling flowchart of spent lithium-ion batteries.
从环境保护和资源回收的角度来看，废旧锂离子电池的回收是一个有意义的过程。在本研究中，通过低温热处理回收工艺首次同时实现了有机物去除、电极材料解离以及高价态过渡金属还原，这些是有价金属回收效率的关键点。同时对有机物的热解特性、废旧正极材料的相变行为及热还原机理进行了评估。结果表明，热解可去除有机物并提高电极材料的解离度。基于有机物、铝箔和导电添加剂的还原作用，正极材料中的高价态过渡金属同步还原为CoO、NiO、MnO、Ni和Co。同时，Li元素以LiCO、LiF和铝锂化合物的形式存在，在水冲击破碎过程中可通过水浸回收，而过渡金属在无还原剂的情况下可通过酸浸回收。水浸过程中Li的回收率可达81.26%，Ni、Co、Mn的综合回收率分别为92.04%、93.01%、92.21%。本研究可为废旧锂离子电池提供一个环保的回收流程。
