SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2023, Vol. 54 ›› Issue (2): 306-315.DOI: 10.1016/j.cjche.2022.04.005

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Recovery of Li2CO3 and FePO4 from spent LiFePO4 by coupling technics of isomorphic substitution leaching and solvent extraction

Yong Niu1,2,4, Xiaowu Peng1,2, Jinfeng Li3, Yuze Zhang1,2, Fugen Song1,2, Dong Shi1,2, Lijuan Li1,2,5   

  1. 1. Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Engineering Laboratory for Green Applications of Salt Lakes and Salt Deposits, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China;
    2. Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources, Xining 810008, China;
    3. Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China;
    4. University of Chinese Academy of Sciences, Beijing 100049, China;
    5. Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2021-10-18 Revised:2022-04-01 Online:2023-05-11 Published:2023-02-28
  • Contact: Fugen Song,E-mail:songfugen@isl.ac.cn;Dong Shi,E-mail:shidong@isl.ac.cn;Lijuan Li,E-mail:lilijuanisl@163.com
  • Supported by:
    This work was financially supported by the National Natural Science Foundation of China (U1707601), project of Youth Innovation Promotion Association, Chinese Academy of Sciences (2021430), project of Innovation Academy for Green Manufacture, Chinese Academy of Sciences (IAGM2020C26) and project of Bureau of International Cooperation, Chinese Academy of Sciences (122363KYSB20190033).

Recovery of Li2CO3 and FePO4 from spent LiFePO4 by coupling technics of isomorphic substitution leaching and solvent extraction

Yong Niu1,2,4, Xiaowu Peng1,2, Jinfeng Li3, Yuze Zhang1,2, Fugen Song1,2, Dong Shi1,2, Lijuan Li1,2,5   

  1. 1. Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Engineering Laboratory for Green Applications of Salt Lakes and Salt Deposits, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China;
    2. Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources, Xining 810008, China;
    3. Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China;
    4. University of Chinese Academy of Sciences, Beijing 100049, China;
    5. Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
  • 通讯作者: Fugen Song,E-mail:songfugen@isl.ac.cn;Dong Shi,E-mail:shidong@isl.ac.cn;Lijuan Li,E-mail:lilijuanisl@163.com
  • 基金资助:
    This work was financially supported by the National Natural Science Foundation of China (U1707601), project of Youth Innovation Promotion Association, Chinese Academy of Sciences (2021430), project of Innovation Academy for Green Manufacture, Chinese Academy of Sciences (IAGM2020C26) and project of Bureau of International Cooperation, Chinese Academy of Sciences (122363KYSB20190033).

Abstract: Efficient and low-cost recycling of spent lithium iron phosphate (LiFePO4, LFP) batteries has become an inevitable trend. In this study, an integrated closed-loop recycling strategy including isomorphic substitution leaching and solvent extraction process for spent LFP was proposed. An inexpensive FeCl3 was used as leaching agent to directly substitute Fe2+ from LFP. 99% of Li can be rapidly leached in just 30 min, accompanied by 98% of FePO4 precipitated in lixivium. The tri-n-butyl phosphate (TBP)-sulfonated kerosene (SK) system was applied to extract Li from lixivium through a twelve-stage countercurrent process containing synchronous extraction and stepwise stripping of Li+ and Fe3+. 80.81% of Li can be selectively enriched in stripping liquor containing 3.059 mol·L-1 of Li+ under optimal conditions. And the Fe stripping liquor was recovered for LFP re-leaching, of which, Fe2+ was oxidized to Fe3+ by appropriate H2O2. Raffinate and lixivium were concentrated and entered into extraction process to accomplished close-loop recycling process. Overall, the results suggest that more than 99% of Li was recovered. FeCl3 holding in solution was directly regenerated without any pollutant emission. The sustainable mothed would be an alternative candidate for total element recycling of spent LFP batteries with industrial potential.

Key words: Spent LiFePO4, Leaching lithium, Extraction, Stripping, Recovery

摘要: Efficient and low-cost recycling of spent lithium iron phosphate (LiFePO4, LFP) batteries has become an inevitable trend. In this study, an integrated closed-loop recycling strategy including isomorphic substitution leaching and solvent extraction process for spent LFP was proposed. An inexpensive FeCl3 was used as leaching agent to directly substitute Fe2+ from LFP. 99% of Li can be rapidly leached in just 30 min, accompanied by 98% of FePO4 precipitated in lixivium. The tri-n-butyl phosphate (TBP)-sulfonated kerosene (SK) system was applied to extract Li from lixivium through a twelve-stage countercurrent process containing synchronous extraction and stepwise stripping of Li+ and Fe3+. 80.81% of Li can be selectively enriched in stripping liquor containing 3.059 mol·L-1 of Li+ under optimal conditions. And the Fe stripping liquor was recovered for LFP re-leaching, of which, Fe2+ was oxidized to Fe3+ by appropriate H2O2. Raffinate and lixivium were concentrated and entered into extraction process to accomplished close-loop recycling process. Overall, the results suggest that more than 99% of Li was recovered. FeCl3 holding in solution was directly regenerated without any pollutant emission. The sustainable mothed would be an alternative candidate for total element recycling of spent LFP batteries with industrial potential.

关键词: Spent LiFePO4, Leaching lithium, Extraction, Stripping, Recovery