废旧磷酸铁锂电池阴极片低温热处理-球磨实验研究

Experimental study on low temperature heat treatment-ball milling of cathode sheet of waste lithium iron phosphate battery

针对磷酸铁锂电池大量退役亟需回收的现状,文章进行低温热处理-球磨工艺分离回收电池阴极片材料的研究。采用正交试验探究不同热处理温度和时间下阴极片粘接剂热变形程度与不同球磨参数的实验效果;并利用电镜扫描和X射线衍射(X-ray diffraction,XRD)分析低温热处理-球磨工艺回收产物的品质。实验结果表明:低温热处理可以大幅减弱粘接剂的粘接强度,低温热处理-球磨可以实现磷酸铁锂与集流体间的有效解离,且回收产物品质满足下游回收再利用要求;整个工艺流程经济效益好、无二次污染;在恒温90 min、250℃的热处理环境与磨料直径15 mm、球磨时间45 s的实验参数下,材料的解离率达88.7%,磷酸铁锂纯度为92.8%。

For the current situation that a large number of spent lithium iron phosphate batteries need to be recovered urgently,the separation and recovery of cathode sheet materials by low temperature heat treatment-ball milling process were studied.The orthogonal experiment was used to investigate the thermal deformation degree of cathode adhesive under different heat treatment temperature and time and the experimental effect of different ball milling parameters.The quality of the product recovered by the low temperature heat treatment-ball milling process was analyzed by scanning electron microscope(SEM)and X-ray diffraction(XRD).The experimental results show that low temperature heat treatment can greatly weaken the bonding strength of the adhesive,low temperature heat treatment-ball milling can realize the effective dissociation between lithium iron phosphate and current collector,and the quality of the recovered product meets the downstream recycling requirements.The whole process has good economic effect and no secondary pollution.The dissociation rate and purity of lithium iron phosphate are 88.7% and 92.8% respectively under the experimental conditions of 250℃,constant temperature of 90 min,abrasive diameter of 15 mm and ball milling time of 45 s.