Recycling of spent LiFePO₄ batteries has drawn recent attention relating to recovering their high contents of rare elements and negating potential negative environmental effects of their disposal. However, the stable crystal structure of LiFePO₄ materials has prevented the development of a recycling process with high selectivity and extraction efficiency. We report the selective extraction of Fe and Li from spent LiFePO₄ batteries via an environmentally friendly mechanochemical process with oxalic acid. With the use of a mechanochemical treatment and water leaching, the Li extraction efficiency can be improved to 99%. Furthermore, 94% of Fe can be simultaneously recovered as FeC₂O₄·2H₂O. To understand the reaction mechanism and determine the optimum reaction conditions, we investigated various parameters, including the LiFePO₄ to oxalic acid mass ratio, rotation speed, milling time, and ball-to-powder mass ratio. Moreover, metal ions from the water leaching process were recovered by chemical precipitation. This study provides an efficient and selective process for recovery of valuable metals from spent LiFePO₄ materials.

中文翻译：

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通过环保的机械化学方法选择性地从废锂离子电池中回收锂和铁

废LiFePO ₄电池的回收在回收高含量的稀有元素和消除其处置对环境的潜在负面影响方面引起了近期关注。然而，LiFePO ₄材料的稳定晶体结构阻碍了具有高选择性和提取效率的再循环工艺的发展。我们报道了通过草酸对环境友好的机械化学过程，从废弃的LiFePO ₄电池中选择性提取铁和锂。通过使用机械化学处理和水浸，可以将锂的提取效率提高到99％。此外，可以同时回收94％的Fe作为FeC ₂ O ₄ ·2H _2。O.为了了解反应机理并确定最佳反应条件，我们研究了各种参数，包括LiFePO ₄与草酸的质量比，转速，研磨时间和球粉质量比。此外，通过化学沉淀回收了水浸出过程中的金属离子。这项研究为从用过的LiFePO ₄材料中回收有价值的金属提供了一种有效的选择性方法。