The pretreatment of cathode material from spent lithium-ion batteries is employed for the purpose of selective lithium leaching, which combines reduction roasting with mechanochemical activation without any additives. Under a nitrogen atmosphere (600 °C, 240 min), lithium in the cathode material changes into lithium salts and other metals transform into low-valence/elemental states via intricate reactions between LiMn_xCo_yNi_zO₂ and inherent carbon. Then, the transition metals at low-valence and elemental states exhibit relatively slow leaching rates in a short time period, while lithium can efficiently migrate into solution. To further optimize this process, mechanochemical activation via ball milling (10 Hz, 30 min) is employed, decreasing the particle size and inducing a transition from crystal to an amorphous phase, facilitating the efficiency of lithium leaching. Under the low-temperature and short-duration leaching conditions (35 °C, 5 min, 2 mol/L H₂SO₄, 100 g/L), nearly 91.6% lithium is leached out, and the selectivity reaches 92.2%. The lithium solution is further purified by the extractant Versatic 10, and high-purity Li₂CO₃ is precipitated by adding Na₂CO₃. This method is also applied to selectively leach lithium from LiCoO₂ and LiNiO₂ cathodes, achieving remarkable leaching efficiencies of 95.8 and 100%, respectively.

中文翻译：

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通过还原焙烧和机械化学活化相结合从废旧锂离子电池中选择性浸出锂

对废旧锂离子电池正极材料进行预处理，实现选择性浸锂，将还原焙烧与机械化学活化相结合，不添加任何添加剂。在氮气气氛下（600℃，240分钟），正极材料中的锂转变为锂盐，其他金属通过LiMn _x Co _y Ni _z O ₂和固有碳之间的复杂反应转变为低价/元素态。然后，低价和单质态的过渡金属在短时间内表现出相对较慢的浸出速率，而锂可以有效地迁移到溶液中。为了进一步优化该过程，采用球磨（10 Hz，30 分钟）进行机械化学活化，减小颗粒尺寸并诱导从晶体到非晶相的转变，从而促进锂浸出的效率。在低温短时浸出条件下（35℃、5min、2mol/LH ₂ SO ₄、100g/L），锂浸出率接近91.6%，选择性达到92.2%。锂溶液通过萃取剂Versatic 10进一步纯化，并通过添加Na ₂ CO ₃沉淀出高纯度的Li ₂ CO ₃。该方法还应用于从LiCoO ₂和LiNiO ₂正极中选择性浸出锂，分别实现了95.8%和100%的显着浸出率。