磷酸铁锂废料中磷、铁、锂的综合回收

采用氢氧化钠溶液除去经前处理后的废旧磷酸铁锂电池、极片或边角料粉料中的铝, 采用盐酸浸出-双氧水氧化-纯碱调pH值工艺, 得到二水磷酸铁和氯化锂溶液。二水磷酸铁经洗涤后与氢氧化钠反应得到氢氧化铁产品和磷酸三钠水溶液, 磷酸三钠水溶液蒸发结晶得到十二水磷酸三钠产品。氯化锂溶液经进一步除杂和蒸发后与碳酸钠反应得到碳酸锂产品。重点研究了磷酸铁的沉淀以及由磷酸铁制备磷酸三钠的工艺。制得的产品十二水磷酸三钠达到了工业级要求, 主含量高达99.03%。实现了磷、铁、锂的全部综合回收。

Comprehensive Recovery of Phosphorus,Iron and Lithium from Spent Lithium Iron Phosphate Batteries

The pretreated spent lithium iron phosphate batteries, electrode plate or scrap powder was firstly processed with sodium hydroxide solution to remove aluminum, then subjected to a process consisting of leaching with hydrochloric acid, oxidation with hydrogen peroxide and adjusting the pH value with soda, with the iron phosphate and lithium chloride solution obtained. The iron phosphate after washing reacted with sodium hydrogen solution to give ferric hydroxide and trisodium phosphate solution. Trisodium phosphate solution went through the evaporation crystallization process, yielding a trisodium phosphate product. While previously obtained lithium chloride solution, after further purification and evaporation, was reacted with sodium carbonate to yield a lithium carbonate product. The precipitation of ferric phosphate and the process for preparing trisodium phosphate from ferric phosphate were the focuses of the study. It is shown that the obtained sodium phosphate tribasic dodecahydrate has reached the industrial grade requirement, with the main content as high as 99.03%, thus the comprehensive recovery of phosphorus, iron and lithium can be realized.