中文摘要：

采用机械化学法处理废旧锂电池,选择性地回收金属锂,同时将钴转化为钴铁氧体（CoFe_2O_4）功能材料,并重点考察了不同供氯体和操作参数对Li回收率和Co转化率的影响。研究发现,共价类的供氯体不适于Li的回收和CoFe_2O_4的制备,离子类的供氯体具有高的反应活性,不仅可以促进Li的氯化,同时还可以保证Co完整地保留在反应残渣中转化为CoFe_2O_4。将LiCoO_2与Fe粉和NaCl混磨,既可以保证将Li转化为水溶性的盐,又可以在球磨过程中将Co与Fe进行晶格重组,保存在球磨残渣中形成磁性功能材料。确立的最佳操作参数为：m（LiCoO_2）∶m（Fe）∶m（NaCl）为1∶2.5∶5,球料比50∶1,球磨转速600 r·min^-1,时间12 h,此时Li回收率达到92%,Co与Fe保留在残渣中转化为CoFe_2O_4。对产物的晶相组成、形貌和磁性能进行表征发现,所得CoFe_2O_4结构紧密,具有良好的磁学性能,饱和磁化强度Ms为56.1 emu·g^-1,剩余磁化强度Mr为25.8 emu·g^-1,矫顽力Hc为1 165.3 Oe。本研究为废旧锂电池的资源化回收提供了一条清洁环保的新途径。

英文摘要：

The mechanochemical recycling of spent lithium-ion batteries for the selective recovery of Li and simultaneous transformation of Co into CoFe_2O_4 was investigated. This study mainly focused on the effects of different chlorine donors and operating parameters on the Li recovery rate and Co transformation efficiency. It was found that an ionic chlorine donor was much more suitable for Li recovery and Co transformation than a covalent chlorine donor,as it exhibited a much higher activity for improving the chlorination of Li and retaining Co within the residue. By milling LiCoO_2 with NaCl and Fe powder,the Li could be effectively transformed into a water-soluble form,and the Co and Fe crystals could be reshaped to form a magnetic material. The optimum m（ LiCoO_2） ∶ m（ Fe） ∶ m（ NaCl） ratio,ball-to-powder mass ratio,rotation speed,and milling time were 1∶ 2. 5∶ 5,50∶ 1,600 r·min^-1,and 12 h,respectively. Furthermore,the crystal structure,morphology,and magnetic properties of the products were characterized. The results indicate that the prepared cobalt ferrite has a close-packed structure and superior magnetic properties. The saturation magnetization Ms,residual magnetization Mr,and coercivity Hc were 56. 1 emu· g^-1,25. 8 emu·g^-1,and 1 165. 3 Oe,respectively. This study provides an efficient and green approach for the recycling of spent lithium-ion batteries.