Spent lithium-ion batteries (LIBs) are essential secondary resource, containing valuable metal elements including lithium, cobalt, nickel, manganese. Recovering valuable metals from spent LIBs is significant for achieving environmental protection and alleviating resource shortages. Herein, a sustainable and facile process for Li2CO3 and Mn2O3 recovery from spent LiMn2O4 batteries (LMO) was proposed via sulfation roasting with waste copperas. The leaching efficiencies of Li and Mn reached approximately 100 % and 82 % under the optimal conditions, and the final recovered products were Li2CO3 and Mn2O3 with high purities. The sulfation reaction between LMO and copperas was the transition from solid-solid to gas-solid reaction. During the sulfation reaction, LMO spinel structure was decomposed into MnO2 and Mn2O3 crystal structures, and the anti-fluorite structure Li2O embedded in the spinel structure was released. The Li2O was easily to be sulfated, while MnO2 was partly reduced by Fe2+ to more stable spinel structure Mn2O3. Furthermore, FeSO4 decomposed into SO2 gas, which greatly improved the sulfation reaction through permeating into the unreacted core of LMO. As a result, the spinel structure of Mn2O3 was broken, and Mn was escaped to combine with SO42- to form MnSO4. This research provided an alternative technological route for green recovery of spent LMO batteries, demonstrating high potential for broad application.

中文翻译：

---

通过废铜选择性硫酸盐化从废旧 LiMn2O4 电池中回收 Li2CO3 和 Mn2O3 的可持续和简便工艺


废旧锂离子电池 （LIB） 是必不可少的二次资源，含有锂、钴、镍、锰等有价值的金属元素。从废锂离子电池中回收有价金属，对实现环境保护和缓解资源短缺具有重要意义。在此，提出了一种可持续且简单的工艺，通过废铜硫酸化焙烧从废旧 LiMn2O4 电池 （LMO） 中回收 Li2CO3 和 Mn2O3。在最佳条件下，Li 和 Mn 的浸出效率分别达到约 100 % 和 82 %，最终回收的产物为高纯度的 Li2CO3 和 Mn2O3。LMO 和铜之间的硫酸化反应是从固 - 固到气 - 固反应的转变。在硫酸化反应过程中，LMO 尖晶石结构分解为 MnO2 和 Mn2O3 晶体结构，并释放嵌入尖晶石结构中的反萤石结构 Li2O。Li2O 容易被硫酸化，而 MnO2 部分被 Fe2+ 还原成更稳定的尖晶石结构 Mn2O3。此外，FeSO4 分解成 SO2 气体，通过渗透到 LMO 未反应的核心中，大大改善了硫酸盐化反应。结果，Mn2O3 的尖晶石结构被破坏，Mn 被逃逸与 SO42- 结合形成 MnSO4。这项研究为废旧 LMO 电池的绿色回收提供了另一种技术路线，显示出广泛的应用潜力。