采用硫酸-还原剂浸出工艺从废旧锂离子电池中回收LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2

Recovery of LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2 from Spent Lithium Ion Batteries by Leaching with H_2SO_4 and Reductants

采用H_2SO_4-还原剂浸出工艺处理废旧锂离子电池正极材料(LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2),研究了H_2SO_4浓度以及浸出温度对有价金属元素浸出的影响,确定了浸出过程中适宜的H_2SO_4浓度为2 mol/L,浸出温度为40℃。在H_2SO_4浓度为2mol/L、原料与浸出剂比例为100g/L、浸出时间为2h、浸出温度为40℃、搅拌速度为500r/min的优化条件下,通过单因素实验考察了还原剂H_2O_2、C_6H_(12)O_6、Na_2SO_3对有价金属浸出的影响。结果显示,还原剂H_2O_2、C_6H_(12)O_6、Na_2SO_3的最佳添加量分别为4.5%、80g/L、60g/L。通过正交实验考察了混合还原剂的影响,结果表明当还原剂组成为120g/L C_6H_(12)O_6和100g/L Na_2SO_3时,Co、Li、Mn、Ni浸出率分别为93.51%、92.68%、95.61%、92.93%,Al浸出率仅达到18.57%。与单个还原剂相比,通过改变混合还原剂的组成,可在不明显降低有价金属(Li、Ni、Mn、Co)浸出率的情况下,控制杂质金属Al的浸出。另外,对于Al、Li的浸出,影响因素的主次关系分别为:Na_2SO_3>C_6H_(12)O_6>H_2O_2、H_2O_2>Na_2SO_3>C_6H_(12)O_6;对于Co、Mn、Ni的浸出,影响因素的主次关系为C_6H_(12)O_6>H_2O_2>Na_2SO_3。

The cathode materials（LiNi0.6Mn0.2Co0.2O2）in spent lithium ion batteries were processed by leaching with H2SO4 and reductants.The effects of H2SO4 concentration and leaching temperature on the leaching of valuable metals were studied.Optimal H2SO4 concentration and leaching temperature are determined of 2 mol/L and 40℃,respectively during leaching.Under the optimized conditions of H2SO4 concentration of 2 mol/L,the ratio of raw material to leaching agent of 100 g/L,leaching time of 2 h,leaching temperature of 40 ℃ and stirring speed of 500 r/min,the effects of such reductants as H2O2,C6H12O6 and Na2SO3 on the leaching of valuable metals were investigated by single factor experiments.The results show that the optimum addition of H2O2,C6H12O6 and Na2SO3 are 4.5%,80 g/L and 60 g/L,respectively.The effects of mixed reductants were also investigated by orthogonal experiments.When the composition of reductants is 120 g/L C6H12O6 and 100 g/L Na2SO3,the leaching rates of Co,Li,Mn and Ni are 93.51%,92.68%,95.61% and 92.93%,respectively,but the leaching rate of Al is only 18.57%.Compared with single reductant,mixed reductants with suitable composition can control the leaching of the impurity metal of Al under the condition that the leaching rate of valuable metals（Li、Ni、Mn、Co）is not obviously reduced.In addition,the factors affecting Al and Li leaching have the following primary and secondary orders：Na2SO3〉C6H12O6〉H2O2 and H2O2〉Na2SO3〉C6H12O6,respectively.And the factors affecting Co,Mn and Ni leaching have the following primary and secondary order：C6H12O6〉H2O2〉Na2SO3.