Revealing role of oxidation in recycling spent lithium iron phosphate through acid leaching

IF 9.6 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Rare Metals Pub Date : 2024-11-08 DOI:10.1007/s12598-024-03007-x

Dan-Feng Wang, Min Chen, Jing-Jing Zhao, Feng-Yin Zhou, Hong-Ya Wang, Xin Qu, Yu-Qi Cai, Zhi-Yu Zheng, Di-Hua Wang, Hua-Yi Yin

{"title":"Revealing role of oxidation in recycling spent lithium iron phosphate through acid leaching","authors":"Dan-Feng Wang, Min Chen, Jing-Jing Zhao, Feng-Yin Zhou, Hong-Ya Wang, Xin Qu, Yu-Qi Cai, Zhi-Yu Zheng, Di-Hua Wang, Hua-Yi Yin","doi":"10.1007/s12598-024-03007-x","DOIUrl":null,"url":null,"abstract":"<div>The efficient recycling of spent lithium iron phosphate (LiFePO4, also referred to as LFP) should convert Fe (II) to Fe (III), which is key to the extraction of Li and separation of Fe and is not well understood. Herein, we systematically study the oxidation of LiFePO4 in the air and in the solution containing oxidants such as H2O2 and the effect of oxidation on the leaching behaviors of LFP. In the air, O2 breaks down the LFP olivine structure at 550 °C for 1 h by oxidizing Fe (II) to Fe (III) in terms of converting LFP to Li3Fe2(PO4)3 and Fe2O3. After that, Li is leached in 0.5 M sulfuric acid solution and is further recycled as Li3PO4 with a Li recovery efficiency of 97.48%. Meanwhile, Fe is recovered as FePO4 and Fe2O3. Compared with H2SO4–H2O2, the air oxidation saves H2O2 but increases the leaching efficiency of Fe and H2SO4 consumption. The discrepancy of Fe leaching efficiency can be attributed to the different leaching mechanisms involving the solid-to-solid and solid-to-liquid-to-solid conversions. Furthermore, the results of the Everbatt model analysis show that the air roasting-H2SO4 leaching method has low emission and potentially high income, which is simple and safe. Overall, this work will deepen the understanding of acid leaching of LFP and favorably stimulate the maturation of the LFP recycling technique.<h3>Graphical abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":749,"journal":{"name":"Rare Metals","volume":"44 3","pages":"2059 - 2070"},"PeriodicalIF":9.6000,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Rare Metals","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s12598-024-03007-x","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

The efficient recycling of spent lithium iron phosphate (LiFePO₄, also referred to as LFP) should convert Fe (II) to Fe (III), which is key to the extraction of Li and separation of Fe and is not well understood. Herein, we systematically study the oxidation of LiFePO₄ in the air and in the solution containing oxidants such as H₂O₂ and the effect of oxidation on the leaching behaviors of LFP. In the air, O₂ breaks down the LFP olivine structure at 550 °C for 1 h by oxidizing Fe (II) to Fe (III) in terms of converting LFP to Li₃Fe₂(PO₄)₃ and Fe₂O₃. After that, Li is leached in 0.5 M sulfuric acid solution and is further recycled as Li₃PO₄ with a Li recovery efficiency of 97.48%. Meanwhile, Fe is recovered as FePO₄ and Fe₂O₃. Compared with H₂SO₄–H₂O₂, the air oxidation saves H₂O₂ but increases the leaching efficiency of Fe and H₂SO₄ consumption. The discrepancy of Fe leaching efficiency can be attributed to the different leaching mechanisms involving the solid-to-solid and solid-to-liquid-to-solid conversions. Furthermore, the results of the Everbatt model analysis show that the air roasting-H₂SO₄ leaching method has low emission and potentially high income, which is simple and safe. Overall, this work will deepen the understanding of acid leaching of LFP and favorably stimulate the maturation of the LFP recycling technique.

Graphical abstract

查看原文本刊更多论文

废磷酸铁锂（LiFePO4，又称 LFP）的有效回收利用应将 Fe (II) 转化为 Fe (III)，而 Fe (III) 是萃取锂和分离铁的关键，但目前人们对这一问题还不甚了解。在此，我们系统研究了 LiFePO4 在空气中和含有 H2O2 等氧化剂的溶液中的氧化过程，以及氧化对 LFP 浸出行为的影响。在空气中，O2 在 550 °C 下持续 1 小时，通过将 Fe (II) 氧化为 Fe (III)，将 LFP 分解为 Li3Fe2(PO4)3 和 Fe2O3，从而破坏 LFP 橄榄石结构。之后，锂在 0.5 M 硫酸溶液中浸出，并以 Li3PO4 的形式进一步回收，锂的回收率为 97.48%。同时，铁以 FePO4 和 Fe2O3 的形式被回收。与 H2SO4-H2O2 相比，空气氧化节省了 H2O2，但增加了铁的浸出效率和 H2SO4 的消耗。铁浸出效率的差异可归因于涉及固-固和固-液-固转化的不同浸出机制。此外，Everbatt 模型分析结果表明，空气焙烧-H2SO4 浸出法具有低排放和潜在高收益的特点，且简单安全。总之，这项工作将加深人们对全氟辛烷磺酸酸浸法的理解，并有利于促进全氟辛烷磺酸回收技术的成熟。图文摘要

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Rare Metals 工程技术-材料科学：综合

CiteScore

12.10

自引率

12.50%

发文量

2919

审稿时长

2.7 months

期刊介绍： Rare Metals is a monthly peer-reviewed journal published by the Nonferrous Metals Society of China. It serves as a platform for engineers and scientists to communicate and disseminate original research articles in the field of rare metals. The journal focuses on a wide range of topics including metallurgy, processing, and determination of rare metals. Additionally, it showcases the application of rare metals in advanced materials such as superconductors, semiconductors, composites, and ceramics.