失效锂离子电池材料真空热处理及氨性浸出

研究了失效锂离子电池中塑料、电极隔膜等有机物的真空脱除,并以电池级纯钴酸锂(LiCoO2)为原料,与活性炭粉混合,在真空中进行热还原,还原产物用含NH3和NH4HCO3的氨性水溶液浸出。实验结果表明,当加热温度大于450℃,真空压力<400 Pa时,失效锂离子电池中有机挥发物基本被脱除。在400℃真空温度下纯LiCoO2不被炭粉还原;当还原温度达到600℃,LiCoO2转变为CoO、Co和Li2CO3;在800℃时,还原产物主要为六方相、立方相金属钴及少量的CoO。还原产物中的钴易于被氨性水溶液浸出,浸出3 h后,钴基本进入溶液中,锂的浸出率也达到97%以上。

Heating treatment of spent lithium-ion batteries and ammoniacal leaching of product of LiCoO2 reduced by carbon in vacuum

The removal of organics from spent lithium-ion batteries,such as outer plastic shell and electrode membrane by vacuum distillation was studied.Battery-grade LiCoO2 was reduced by activated carbon using vacuum carbonthermal reduction method,and then the reduced mixture was leached in ammoniacal aqueous solution containing NH3 and NH4HCO3.Experimental results demonstrated that all the organics were removed at 450℃ under the vacuum pressure of 400 Pa.There was no reaction between LiCoO2 and carbon when heating temperature was below 400℃ under vacuum condition.Co and Li elements in the mixture of LiCoO2 and carbon were then transformed into CoO,Co and Li2CO3 phases at 600℃.Cobalt metal in cubic and hexagonal structures and a small amount of CoO were obtained at 800℃.The reduced product was easily leached out in the ammoniacal solution.Cobalt phases were dissolved into solution with leaching time up to 3 h,and the leaching ratio of lithium was above 97%.