摘要
采用球磨-低温热处理两阶段流程可以将阻碍钴酸锂和石墨浮选分离的锂电池电极材料表面有机物膜去除,通过TG-DSC综合热分析、接触角、XPS测试进行机理研究。结果表明:机械球磨过程可以破坏石墨表面有机物膜,而钴酸锂表面有机物膜的去除需进行进一步处理。为去除钴酸锂表面有机物,同时避免石墨的损失,热处理温度应不高于500℃。在400℃焙烧30 min后,钴酸锂表面表面有机物的结构受到破坏,C—F键和P—F键打开后,F与活性材料中的Li、Co结合,转化为结合能更低的Li—F键和Co—F键,从而降低钴酸锂接触角,增大与疏水石墨表面的性质差异。再经浮选流程,钴酸锂回收率和品位高达90.32%和88.03%,达到了良好的分选效果。XRD、SEM、DES结果表明:浮选产品物相没有受到破坏,表面有机物被去除干净,具有直接重生再造的潜能。
The organic film on the surface of the lithium battery electrode material that hinders the separation of lithium cobaltate and graphite by flotation can be removed by two-stage process of ball milling-low temperature heat treatment. The mechanism study was conducted by TG DSC thermal analysis, contact angle and XPS test. The results show that the mechanical milling process can destroy the organic film on the graphite surface, and lithium cobalt oxide needs further processing. In order to remove the lithium cobalt oxide surface organic material while avoiding the loss of graphite, the heat treatment temperature should not exceed 500 ℃. When calcined at 400 ℃ for 30 min, the structure of PVDF on the surface of lithium cobalt oxide is destroyed. After the C F bond and P F bond are opened, the F element is combined with Li and Co in the active material to convert to Li F bond and Co F bond with lower binding energy, this reduces the contact angle of lithium cobalt oxide and increases the difference in surface properties with hydrophobic graphite. After the flotation process is conducted, the recovery rate and grade of lithium cobaltate are as high as 90.32% and 88.03%, achieving a good flotation effect. XRD, SEM, and DES test results show that the flotation product phase is not damaged, the surface organics are removed, and it has the potential for direct regeneration.
作者
黄红军
黄秋森
HUANG Hong-jun;HUANG Qiu-sen(School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2019年第4期878-886,共9页
The Chinese Journal of Nonferrous Metals
基金
中南大学"创新驱动计划"项目(2015CX005)~~
关键词
锂电池电极材料
浮选回收
球磨
低温热处理
lithium battery electrode materials
flotation recovery
ball milling
low temperature heat treatment
