化学学报 ›› 2021, Vol. 79 ›› Issue (8): 1073-1081.DOI: 10.6023/A21030083 上一篇    下一篇

研究论文

退役锂离子电池碳/硫协同选择性提锂技术

徐平a, 张西华a,*(), 马恩a, 饶富a, 刘春伟b, 姚沛帆a, 孙峙b,*(), 王景伟a   

  1. a 上海第二工业大学电子废弃物研究中心 资源循环科学与工程中心 上海电子废弃物资源化协同创新中心 上海 201209
    b 北京市过程污染控制工程技术研究中心 中国科学院过程工程研究所环境技术与工程研究部 中国科学院绿色过程制造创新研究院 北京 100190
  • 投稿日期:2021-03-07 发布日期:2021-07-19
  • 通讯作者: 张西华, 孙峙
  • 基金资助:
    国家自然科学基金(51874269); 上海第二工业大学校基金(EGD20XQD06); 上海市高原学科—环境科学与工程(资源循环科学与工程)

Selective Recovery of Lithium from Spent Lithium-ion Batteries Synergized by Carbon and Sulfur Elements

Ping Xua, Xihua Zhanga(), En Maa, Fu Raoa, Chunwei Liub, Peifan Yaoa, Zhi Sunb(), Jingwei Wanga   

  1. a WEEE Research Centre, Research Center of Resource Recycling Science and Engineering, Shanghai Polytechnic University; Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai 201209, China
    b Beijing Engineering Research Center of Process Pollution Control; Division of Environment Technology and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2021-03-07 Published:2021-07-19
  • Contact: Xihua Zhang, Zhi Sun
  • Supported by:
    National Natural Science Foundation of China(51874269); Research fund of Shanghai Polytechnic University(EGD20XQD06); Gaoyuan Discipline of Shanghai - Environmental Science and Engineering(Resource Recycling Science)

针对当前退役锂离子电池有价金属提取工艺选择性差、环境风险突出的瓶颈问题, 提出了碳/硫协同选择性提锂的新思路. 首先在系统考察(NH4)2SO4、NH4HSO4、NaHSO4和H2SO4分别作为焙烧剂对退役锂离子电池LiNi1/3Co1/3Mn1/3O2正极粉末中锂的浸出选择性、环境友好性和经济性影响的基础上, 确定H2SO4为最佳焙烧剂. 基于此, 研究了石墨添加量对LiNi1/3Co1/3Mn1/3O2中锂的浸出选择性的影响, 揭示了C/S协同强化锂的浸出选择性的转化路径及其机制. 结果表明, 在LiNi1/3Co1/3Mn1/3O2与H2SO4物质的量比为2∶1、石墨添加量为20% (w)、焙烧温度为600 ℃、焙烧时间为120 min的最优条件下, LiNi1/3Co1/3Mn1/3O2中锂的浸出率高达93%, 回收的Li2CO3纯度高于电池级Li2CO3纯度要求; Ni、Co和Mn均进入渣相, 经分离纯化后可作为合成正极材料的前驱物, 分离得到的石墨可回用于硫化焙烧过程的添加剂. 通过对LiNi1/3Co1/3Mn1/3O2混合粉末(含20 wt.%石墨)硫化焙烧热行为及其产物X射线衍射(XRD)表征表明, 石墨的添加降低了硫化焙烧的反应温度, 通过C/S协同作用强化了LiNi1/3Co1/3Mn1/3O2中锂的选择性浸出, 且不产生SOx等有毒有害气体. 本工作结合硫化焙烧和碳热还原优势, 为退役锂离子电池正负极材料的同步循环利用开辟了新思路, 实现了LiNi1/3Co1/3Mn1/3O2中锂的高效选择性清洁提取和废石墨负极的循环利用.

关键词: 退役锂离子电池, 硫化焙烧, 废石墨, 选择性提取,

Recycling of spent lithium-ion batteries (LIBs) has attracted ever-growing attention globally owing to the scarcity of critical metals and potential environmental risk. To solve the bottlenecks including poor selectivity and prominent environmental risks during the recovery of valuable metals from spent LIBs, the work proposed a novel process for selectively recovery of lithium synergized by carbon and sulfur elements. Firstly, H2SO4 was determined as the optimal roasting reagent by systematically investigating the effects of various roasting reagents including NaHSO4, (NH4)2SO4, NH4HSO4 and H2SO4 on the leaching selectivity of lithium from the LiNi1/3Co1/3Mn1/3O2 active material in spent LIBs, environmental impact and cost of reagents. Then, the effect of graphite dosage on the selectivity of lithium from LiNi1/3Co1/3Mn1/3O2 is investigated. Finally, the conversion path and mechanism under the synergistic effect of C and S elements for enhancing the selectivity of lithium is revealed. It is found that the leaching efficiency can achieve 93% under the following optimal conditions: the molar ratio of LiNi1/3Co1/3Mn1/3O2 to H2SO4 of 2∶1, graphite dosage of 20% (w), roasting temperature of 600 ℃, and roasting time of 120 min. The purity of the precipitated Li2CO3 from the obtained leachate is higher than that of battery grade Li2CO3. Ni, Co and Mn from LiNi1/3Co1/3Mn1/3O2 almost remains in the leaching residue which can be employed as the precursor materials for synthesizing cathode materials after separation and purification treatment. In addition, the separated graphite can be reused as roasting additive during the sulfation roasting of LiNi1/3Co1/3Mn1/3O2. By analyzing the thermal behavior of the mixed powder of LiNi1/3Co1/3Mn1/3O2 and graphite, along with the X-ray diffraction (XRD) characterization of the roasting products, it is found that the roasting temperature can be reduced by the addition of waste graphite, the selectivity of lithium can be enhanced under the synergistic effect of C and S elements. Most importantly, no hazardous gases such as SOx are generated. This work proposed a new solution for simultaneous recycling of cathode and anode materials by combing the advantages of sulfation roasting and carbothermal reduction, thus the efficient, selective and cleaner extraction of lithium and the circulating utilization of waste graphite can be achieved.

Key words: spent lithium-ion battery, sulfation roasting, waste graphite, selective recovery, lithium