摘要
为实现对废旧磷酸铁锂电池的高效资源化回收,提出了一种双氧水氧化—酸浸—浸出液二次浸出的工艺回收正极材料中的Li。通过浸出液二次浸出,选择性地从LiFePO_(4)/C中浸出Li,既减少了双氧水的用量,又提高了锂离子浸出率。通过扫描电子显微镜(SEM)、原子吸收光谱仪(AAS)、X-粉末衍射仪(XRD)等分析表征手段考察了浸出温度、浸出时间、液固比(L/S)、pH以及H_(2)O_(2)/Li的摩尔比对Li、Fe、P元素浸出率的影响。结果表明,通过浸出液的二次浸出,Li的浸出率从94.82%上升到99.46%;同时,Fe和P的浸出率分别控制在0.03%和2.3%之内,为后续Fe、P的回收创造了有利条件。所得的Li_(2)SO_(4)浸出滤液,经过进一步的除杂和沉锂后得到Li2CO3白色粉末;Fe、P以橄榄型无水FePO_(4)的形式存在于灰色浸出渣中。本研究结果可为废旧磷酸铁锂电池正极材料中锂的工业化回收提供参考。
In order to achieve the efficient resource recovery of waste lithium iron phosphate batteries, this paper proposed a process of oxidation-acid leaching-secondary leaching of the filtrate via hydrogen peroxide to recycle Li from the cathode material. By selectively leaching of Li from LiFePO_(4)/C in secondary leaching of the filtrate, the consumption amount of hydrogen peroxide reduced and the leaching rate of lithium ion was improved. The effects of leaching temperature, leaching time, liquid-solid ratio(L/S), pH and the molar ratio of H_(2)O_(2)/Li on the leaching rates of Li, Fe and P were investigated by scanning electron microscopy(SEM), atomic absorption spectroscopy(AAS), X-ray powder diffraction(XRD) and other analytical detection methods. The results showed that the leaching rate of Li increased from 94.82% to 99.46% through secondary leaching of the filtrate, and the leaching rates of Fe and P were controlled within 0.03% and 2.3%, respectively, further creating favorable conditions for the subsequent recycle of Fe and P. White powder of Li2CO3was obtained via further impurity removal and lithium deposition of the resulting Li_(2)SO_(4)filtrate;Fe and P were presented in the gray leaching slag with the form of olive-shaped anhydrous FePO_(4). This paper provides a reference for the industrial recycling of lithium from the cathode materials of waste lithium iron phosphate batteries.
作者
梅华贤
伍泽广
陈核章
宋红柚
MEI Huaxian;WU Zeguang;CHEN Hezhang;SONG Hongyou(School of Chemistry and Chemical Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Hunan Provincial Key Laboratory of Clean Coal Resources Utilization and Mine Environmental Protection,Hunan University of Science and Technology,Xiangtan 411201,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2022年第12期4121-4129,共9页
Chinese Journal of Environmental Engineering
基金
湖南省普通高等学校教学改革项目(湘教通[2019]291号-476)
湖南省教育厅科学研究重点项目(21A0315)。
关键词
废旧磷酸铁锂电池
酸浸
分段浸出
浸出率
waste lithium iron phosphate batteries
acid leaching
segmented leaching
leaching rate
