柠檬酸溶解废锂离子电池正极材料的研究

摘要

探求废锂离子电池正极材料LiMn2 O4在柠檬酸溶液中的溶解条件，为废旧电池的进一步回收利用奠定基础。采用单因素与正交实验相结合的方法，对废锂离子电池正极材料LiMn2 O4在柠檬酸溶液中的溶解条件进行研究，结果表明，废锂离子电池正极材料LiMn2 O4在柠檬酸溶液中适宜的溶解条件为：柠檬酸浓度1.0mol· L-1、溶解温度45℃、H2 O2加入量5.0％、料液比60g· L-1，在此条件下正极材料LiMn2 O4在柠檬酸溶液中的溶解率达到99.56％。对柠檬酸溶解废锂离子电池正极材料LiMn2 O4的机理进行了探讨，认为在加入H2 O2之前，尖晶石LiMn2 O4中的Mn3＋发生歧化反应生成Mn2＋以及MnO2，而Mn4＋在溶液中水解生成MnO2。MnO2与柠檬酸发生氧化还原反应生成丙酮二羧酸及Mn 2＋。加入H 2O 2之后，H 2O 2作为还原剂能够将剩余的MnO 2全部还原为 Mn2＋，使正极材料LiMn2 O4在柠檬酸溶液中的溶解率得以提高。%The foundation for the further recycling of the waste battery was laid through the research on the solution conditions of waste lithium-ion battery anode material .The optimum dissolution conditions of lithium-ion battery anode material LiMn 2 O4 in citric acid were determined by a single factor and orthogonal test .The optimum dissolution conditions were the concentration of citric acid,1.0 mol· L-1;the dissolution temperature ,45℃;the added content of H 2 O2 ,5.0%;the solid-liquid ratio,60 g·L -1 .And the dissolution ratio was 99.56%under the optimum solution conditions .The dissolution mechanism of waste lithium-ion battery anode material LiMn2O4in citric acid was discussed.First,Mn3+of spinel LiMn2O4 was disproportionated to Mn2+and MnO2,Mn 4+ of spi-nel LiMn 2O 4 was hydrolyzed to MnO 2 .And,MnO2 underwent a redox reaction in citric acid leading to the formation of acetone dicar -boxylic acid and Mn2+.Then,MnO2 was reduced to Mn2+by reductive agent H2O2.And the dissolution ratio can be increased .