Potassium Pyrosulfate-Assisted Roasting and Water Leaching for Selectively Li and Fe Recycling from Spent LiFePO 4 Batteries

作者：Haoquan Hu, Xianghao Meng, Yin Li, Yusong Yang, Yanqiu Xu, Junxian Hu, Yaochun Yao · 发表于：ACS Sustainable Chemistry & Engineering · 年份：2024 · DOI：10.1021/acssuschemeng.4c04236 · 被引用次数：25 · 研究领域：Extraction and Separation Processes、Advancements in Battery Materials、Recycling and Waste Management Techniques

In the era of extensive deployment of LiFePO 4 batteries in energy storage and electric vehicle domains, the recycling of lithium from spent LiFePO 4 (SLFP) batteries has emerged as a focus, which helps in alleviating environmental pollution and resource shortages. Traditional recycling techniques, encompassing pyrometallurgical and hydrometallurgical methods, are often marred by low selectivity and extraction efficiency. Herein, an eco-friendly and low-consumption recycling strategy involving potassium pyrosulfate (K 2 S 2 O 7 )-assisted low-temperature roasting and subsequent water leaching has been developed for selectively recycling Fe and Li from SLFP batteries. The proposed strategy, compared to the conventional inorganic acid leaching method, mitigates the environmental hazards caused by acidic wastewater generation and reduces the costs associated with wastewater treatment. Investigations of thermal performance characterization and thermodynamic calculation analyses have revealed that K 2 S 2 O 7 plays a pivotal role in extracting lithium from the Fe–P–O framework, converting lithium into a soluble sulfate variant and iron into insoluble compounds. This process culminates in the segregation of a lithium-rich leachate and an iron-enriched residue, which are further processed to synthesize Li 2 CO 3 and FePO 4 . The effects on Li leaching of the mass ratio of K 2 S 2 O 7 to SLFP, roasting time, roasting temperature, and water leaching time are systematically studied and...