磷酸铁锂正极废料选择性提锂制备电池级碳酸锂

废旧磷酸铁锂电池回收对减少环境污染与缓解锂资源压力有重要意义。传统废旧磷酸铁锂电池回收存在锂回收率低、废水处理成本高的问题。通过借鉴Li-Fe-P-H2O系E~pH图及磷酸铁锂电池充放电脱嵌锂的过程,提出采用“过氧化氢+硫酸”体系选择性回收锂。经XRD、SEM检测,提锂后橄榄石型的FePO4结构与原始LiFePO4相结构保持一致,微观形貌的变化也很小。优化条件下Li浸出率达98%以上,同时Fe、P的浸出率在0.1%以下。得到的锂浸出液经净化后成功制备出电池级的碳酸锂。

Preparation of Battery Grade Lithium Carbonate by Selective Extraction of Lithium from Waste Lithium Iron Phosphate Cathode

The recycling of waste lithium iron phosphate (LFP) batteries is of great significance to reduce environmental pollution and relieve pressure of lithium resources. The traditional method for recycling of waste LFP battery has the problems of low lithium recovery and high cost of waste water treatment. The system of "H2O2+H2SO4" was proposed to selectively recover lithium which was inspired by E-pH diagram of Li-Fe-P-H2O system and the charging and discharging process of LFP battery. XRD and SEM studies show that the structure of olivine FePO4 is consistent with structure of original LiFePO4 phase and change of micro morphology is also very small. Under the optimized conditions, leaching rate of Li is 98% above, while the leaching rate of Fe and P is 0.1% below. Battery grade lithium carbonate is prepared from the lithium leaching solution after purification.