焙烧对废旧三元锂离子电池电极混料浮选分离的影响  

Effect of Roasting on the Flotation Separation of Electrode Mixtures of Spent Ternary Lithium-lon Batteries

作　　者：杨越 印艾宁 张靖 于嘉崎 涂亚楠[1] YANG Yue;YIN Aining;ZHANG Jing;YU Jiaqi;TU Yanan(School of Chemical and Environmental Engineering,China University of Mining and Technology Beijing,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《有色金属（选矿部分）》2023年第3期33-39,48,共8页Nonferrous Metals（Mineral Processing Section）

基　　金：国家自然科学基金资助项目(51974325);中国矿业大学(北京)大学生创新训练项目(202103038)。

摘　　要：考察了焙烧温度与时间对废旧三元锂离子电池电极混料可浮性的影响,并通过焙烧前后的粒度分析、热重分析以及X射线光电子能谱分析(XPS)阐释了影响机制。结果表明,焙烧可以有效分解聚偏氟乙烯(PVDF)黏结剂与残留电解质,从而消除其对正负极颗粒表面的覆盖,显化正极金属化合物与负极石墨间的表面亲疏水性差异,提高浮选效果;在500℃焙烧60min的条件下效果最好,此时电极粉料的烧失量为13.24%,正、负极材料的产率分别达到了58.97%和27.79%,灰分分别为94.21%和13.94%,贵金属(Li、Ni、Co、Mn)综合回收率分别为94.04%和5.96%,品位分别为39.55%和5.32%。热重分析表明,PVDF的主要分解温度区间为430~580℃,当温度超过580℃,则主要以石墨的燃烧分解为主。XPS分析进一步展示了PVDF和残留电解液的分解特性,且表明在焙烧温度达到600℃,尽管PVDF的分解更为彻底,但同时造成了负极石墨材料的大量烧失。Effect of roasting temperature and time on the floatability of spent ternary lithium-ion batteries(LiBs)electrode mixture was investigated,and the influence mechanism was discussed by particle size analysis,thermogravimetric(TG)analysis,and X-ray photoelectron spectroscopy(XPS)analysis before and after roasting.The results showed that roasting can effectively decompose polyvinylidene fluoride(PVDF)binder and residual electrolyte,removing its covering effect on the surface of cathode and anode particles,thus recovering the difference in surface hydrophilicity between metal compounds and graphite,and improving the flotation effect.The best comprehensive effect was achieved in this study under the condition of roasting 60 min at 500℃.In this case,the burning loss of electrode mixture was 13.24%,the yields of positive and negative materials were 58.97%and 27.79%,the ash content were 94.21%and 13.94%,the recoveries of precious metals(Li,Ni,Co,Mn)were 94.04%and 5.96%,and the grades were 39.55%and 5.32%,respectively.TG analysis showed that the main decomposition temperature range of PVDF was 430580℃.When the temperature was higher than 580℃,it was mainly the combustion decomposition of graphite.XPS analysis further illustrated the decomposition characteristics of PVDF and residual electrolyte,indicating that although PVDF decomposed more thoroughly,more burning lost occurred when the roasting temperature exceeded 600℃.

关 键 词：废旧三元锂离子电池 焙烧 浮选 回收 

分 类 号：TD925[矿业工程—选矿]