An efficient process is proposed for recovery of waste LiMn₂O₄ cathode material, which is one of the most commonly used cathode materials in LIBs. This report constitutes the precipitation thermodynamic analysis and separation experiments based on the water-leaching solutions during the processes of low-temperature calcination with (NH₄)₂SO₄ and water-leaching. Precipitation thermodynamic analysis is undertaken to investigate the effects of initial concentration of the target solution, [N]_T1, excess precipitant, and addition of (NH₄)₂SO₄ on the manganese precipitation in the Mn²⁺–Li⁺–SO₄²⁻–NH₃–NH₄⁺–CO₃²⁻–H₂O system. Moreover, the effects of initial concentration of the target solution, [N]_T2, and excess precipitant on the lithium precipitation in the Li⁺–SO₄²⁻–NH₃–NH₄⁺–CO₃²⁻–H₂O system are investigated. All these factors clearly influence the manganese and lithium precipitation, particularly the [N]_T and the presence of excess precipitant in the system. The precipitation experimental results demonstrate that the optimal conditions are: a precipitation temperature of 35 °C; an excess coefficient of the precipitant of 2.4; the use of NHC-3 to precipitate the ML-3 solution; a maximum precipitation percentage of manganese of 99.96%; and an absence of Li₂CO₃ precipitation. The double-sulfate salts (Li(NH₄)SO₄ & (NH₄)₂SO₄) evaporated and crystallised from the Li⁺/NH₄⁺ solution are mixed with the waste LiMn₂O₄ cathode material for calcination and water leaching, for which the efficiencies of Li and Mn are 100% and 96.89%, respectively. The double-sulfate salts are calcined at 550 °C for 45 min to obtain the Li₂SO₄ product. Finally, the complete recovery and separation of Mn and Li in the waste LiMn₂O₄ cathode material are achieved.

提出了一种有效的方法来回收废LiMn ₂ O ₄阴极材料，该材料是LIB中最常用的阴极材料之一。该报告构成了在（NH ₄）₂ SO ₄低温煅烧和水浸过程中基于水浸溶液的沉淀热力学分析和分离实验。进行了沉淀热力学分析，以研究目标溶液的初始浓度，[N] _T1，过量沉淀剂和添加（NH ₄）₂ SO ₄对Mn ^2+中锰沉淀的影响。–Li ⁺ –SO ₄ ²⁻ –NH ₃ –NH ₄ ⁺ –CO ₃ ²⁻ –H ₂ O系统。此外，目标溶液的初始浓度，[N] _T2和过量的沉淀剂对Li ⁺ -SO ₄ ^2-- NH ₃ -NH ₄ ⁺ -CO ₃ ^2-- H ₂ O系统中锂沉淀的影响被调查。所有这些因素显然都会影响锰和锂的沉淀，特别是[N] _T以及系统中是否存在过多的沉淀剂。沉淀实验结果表明，最佳条件为：沉淀温度为35°C；温度为35°C。沉淀剂的过量系数为2.4；使用NHC-3沉淀ML-3溶液; 锰的最大沉淀百分比为99.96％；并且没有Li ₂ CO ₃沉淀。从Li ⁺ / NH ₄ ⁺溶液蒸发并结晶的双硫酸盐（Li（NH ₄）SO ₄和（NH ₄）₂ SO ₄）与废LiMn ₂ O ₄混合用于煅烧和水浸的正极材料，其Li和Mn的效率分别为100％和96.89％。将双硫酸盐在550℃下煅烧45分钟以获得Li ₂ SO ₄产物。最后，完全回收和分离了废LiMn ₂ O ₄正极材料中的Mn和Li 。