Abstract：
The recovery of spent lithium-ion batteries by traditional acid leaching is limited by serious pollution, complicated technology, and the low purity of Li2CO3. To address the problems of the traditional acid leaching process and increasing demand for decarbonization, a technique for the selective carbonation leaching of Li and the recovery of battery-grade Li2CO3 by a simple concentration precipitation process without acids or bases was developed. The coupling of CO2 and reducing agents could effectively promote the precipitation of MCO3 (M=Ni/Co/Mn) and the selective leaching of Li by decreasing the reducing capability needed for transition metals and decreasing the pH of the solution. The optimal selective leaching process of Li was obtained under 1 MPa CO2 with 20 g/L Na2S2O3 at an L/S ratio of 30 mL/g for 1.5 h. FT-IR, XRD, ICP-MS and other methods were used to reveal the multiphase interfacial reaction mechanism of the carbonation reduction of layered cathode materials, which indicated that the reducing agent Na2S2O3 could promote lattice distortion of the cathode materials and effective separation of Li. In summary, a green and economical method for the selective recovery of battery-grade Li2CO3 using a one-step method of CO2 carbonation recovery in a near-neutral environment was proposed.
摘要：
传统酸浸回收废旧锂离子电池受到严重污染的限制,复杂的技术,和Li2CO3的低纯度。针对传统酸浸工艺存在的问题和脱碳需求不断增加的问题,开发了一种通过不含酸或碱的简单浓缩沉淀法选择性碳化浸出Li和回收电池级Li2CO3的技术。CO2和还原剂的耦合可以通过降低过渡金属所需的还原能力和降低溶液的pH来有效地促进MCO3（M=Ni/Co/Mn）的沉淀和Li的选择性浸出。在1MPaCO2和20g/LNa2S2O3的条件下，L/S比为30mL/g，持续1.5h，获得了Li的最佳选择性浸出工艺。FT-IR，XRD,采用ICP-MS等方法揭示了层状正极材料碳化还原的多相界面反应机理,这表明还原剂Na2S2O3可以促进正极材料的晶格畸变和Li的有效分离。总之,提出了一种在近中性环境中使用一步CO2碳酸化回收方法选择性回收电池级Li2CO3的绿色经济方法。
