The recovery of lithium from spent lithium iron phosphate (LiFePO4) batteries is of great significance to prevent resource depletion and environmental pollution. In this study, through active ingredient separation, selective leaching and stepwise chemical precipitation develop a new method for the selective recovery of lithium from spent LiFePO4 batteries by using sodium persulphate (Na2S2O8) to oxidize LiFePO4 to FePO4. The impact of various variables on the efficiency of lithium leaching was investigated. Moreover, a combination of thermodynamic analysis and characterization techniques such as X-ray diffraction and X-ray photoelectron spectroscopy was employed to elucidate the leaching mechanism. It was found that 98.65% of lithium could be selectively leached in just 35 minutes at 60°C with only 0.2 times excess of Na2S2O8. This high leaching efficiency can be attributed to the stability and lack of structural damage during the oxidation leaching process. The proposed process is economically viable and environmentally friendly, thus showing great potential for the large-scale recycling of spent LiFePO4 batteries.

中文翻译：

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从废旧磷酸铁锂电池中选择性回收锂

从废磷酸铁锂（LiFePO）中回收锂4）电池对于防止资源枯竭和环境污染具有重要意义。本研究通过活性成分分离、选择性浸出和逐步化学沉淀，开发了一种从废旧磷酸铁锂中选择性回收锂的新方法4使用过硫酸钠（Na2S2氧8）氧化LiFePO4至磷酸铁4。研究了各种变量对锂浸出效率的影响。此外，结合热力学分析和X射线衍射和X射线光电子能谱等表征技术来阐明浸出机理。研究发现，在 60°C 的条件下，仅需 35 分钟即可选择性浸出 98.65% 的锂，而 Na 的用量仅过量 0.2 倍2S2氧8。这种高浸出效率可归因于氧化浸出过程中的稳定性和结构破坏的缺乏。该工艺经济可行且环境友好，因此显示出大规模回收废磷酸铁锂的巨大潜力4电池。