基于磷酸铁锂提锂渣的电池级磷酸铁制备工艺研究

Research on the Preparation Process of Battery Grade Iron Phosphate Based on Lithium Iron Phosphate Extraction Slag

针对磷酸铁锂电池回收中只回收锂而提锂渣中因含铝杂质导致大量磷酸铁无法回收利用的难题,提出了一种硝酸浸提磷酸铁的新工艺。通过甲醇电解还原及氢氟酸沉淀技术,在反应时间70℃、反应时间60 min条件下铁浸出率达到93.4%,制备的磷酸铁中铝含量仅为72 mg/kg,磷酸铁各项指标满足HG/T 4701—2021电池级磷酸铁标准,该方法为提锂渣资源回收提供了有效方案。

A new process of nitric acid leaching of iron phosphate is proposed to address the problem of only recovering lithium in the recovery of lithium iron phosphate batteries and extracting a large amount of iron phosphate from lithium slag due to aluminum impurities that cannot be recycled.Through methanol electrolysis reduction and hydrofluoric acid precipitation technology,the iron leaching rate reached 93.4%under the conditions of reaction time of 70℃and 60 minutes.The aluminum mass fraction in the prepared iron phosphate was only 72 mg/kg,and all indicators of iron phosphate met the HG/T 4701-2021 battery grade iron phosphate standard.This method provides an effective solution for the recovery of lithium extraction slag resources.