废旧锂离子电池正极极粉与铝箔高分离及正极极粉的还原浸出  

High separation of positive electrode powder from aluminum foil and reduction leaching of positive electrode powder of waste lithium-ion batteries

作　　者：姚丽 钟盛文[1,2] YAO Li;ZHONG Shengwen(Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;Jiangxi Key Laboratory of Power Battery and Materials,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China)

机构地区：[1]江西理工大学材料冶金化学学部,江西赣州341000 [2]江西理工大学江西省动力电池及材料重点实验室,江西赣州341000

出　　处：《有色金属科学与工程》2024年第4期479-486,共8页Nonferrous Metals Science and Engineering

基　　金：江西省重大科技研发专项“揭榜挂帅”项目(20213AAE02010)。

摘　　要：由于聚偏氟乙烯(PVDF)提供的强大结合力,正极材料和铝箔很难分离。本研究将正极片置于加热的乙二醇中,当乙二醇温度达到PVDF黏结剂的熔融温度后,PVDF由固态逐渐熔化转为液态,此时黏结剂对正极材料与铝箔的黏合力降低,可通过搅拌力的作用,使铝箔和正极材料分离。本文详细分析了正极材料在乙二醇中搅拌时受到的力,并引入了边界层理论,提出了边界层描述的布拉修斯解,计算了分离铝箔和正极材料的理论搅拌线速度。通过流体动力学计算表明,在乙二醇中分离正极材料的理论搅拌线速度为5.08 m/s,即当搅拌速度大于441 r/min时,正极材料在乙二醇中所受合力大于0,可以实现与铝箔的分离。实验结果表明,在加热温度180℃、搅拌速度550 r/min、搅拌时间120 min的条件下,剥离率可达93.00%以上,与理论转速相符合。分离得到的正极粉末采用硫酸-茶多酚体系还原浸出,最终在硫酸浓度1.25 mol/L、茶多酚含量5 g/L、浸出温度65℃、浸出时间90 min的较优条件下得到锂、镍、钴、锰的浸出率均大于95.00%。Considering the strong binding force provided by polyvinylidene fluoride(PVDF),it is challenging to separate the positive electrode material from the aluminum foil.In this study,the positive electrode sheet was placed in heated ethylene glycol.As the temperature of ethylene glycol reached the melting point of the PVDF binder,PVDF gradually changed from a solid to a liquid state.At this point,its adhesive force on both the positive electrode material and aluminum foil decreased,allowing separation through the action of stirring forces.A detailed analysis of the forces acting on the positive electrode material was conducted during stirring in ethylene glycol,and the boundary layer theory was employed,proposing the Blasius solution for describing the boundary layer.The theoretical stirring linear velocity required for separating the aluminum foil from the positive electrode material was calculated.Fluid dynamics calculations demonstrated that the theoretical stirring linear velocity for separating positive electrode material in ethylene glycol was 5.08 m/s,corresponding to a rotational speed exceeding 441 r/min.When the rotational speed reached this value,the positive electrode material generated a net force greater than zero in ethylene glycol,enabling its separation from the aluminum foil.Experimental results showed that under conditions of heating at 180℃,stirring at 550 r/min,and a stirring time of 120 min,the delamination rate exceeded 93.00%,consistent with the theoretical rotational speed.The separated positive electrode powder was subjected to a sulfuric acid-catechol system for reduction and leaching.Ultimately,under the optimal conditions of a sulfuric acid concentration of 1.25 mol/L,catechol content of 5 g/L,a leaching temperature of 65℃,and a leaching time of 90 min,the leaching rates for lithium,nickel,cobalt,and manganese all surpassed 95.00%.

关 键 词：正极材料 铝箔 废弃锂电池 流体力学 浸出 

分 类 号：TD952[矿业工程—选矿]