废旧磷酸铁锂正极材料除铝的研究进展

Progress in Aluminum Removal for Spent LiFePO_(4) Cathodes

针对废旧磷酸铁锂正极材料夹带残留的铝集流体,导致回收制备的磷酸铁含铝量普遍偏高的问题,本文系统总结了磷酸铁锂正极材料除铝的研究现状,通过简要介绍了各种除铝方法的原理和优劣势,提出深度除铝技术的发展趋势。碱浸法、选择性酸浸法、离子树脂交换法和化学沉淀法均可有效脱除铝杂质,提高产品品质。其中,碱浸法除铝效果佳,但存在碱耗量大和高盐废水产生量大等问题;选择性酸浸法具有操作简单、成本低等优点,但存在选择性低、除铝不彻底等不足,有待进一步完善;离子树脂交换法的铁铝分离指标较好,但实际成本较高,尚未实现工业化应用;化学沉淀法具备操作简单、过程易控制、可深度除铝等优势,是最具发展前景的技术方法。

The spent lithium iron phosphate cathode materials are always entrainment with residual aluminum foil collector,resulting in the high aluminum-content of recycled ferro-phosphorus.Therefore,the research process in aluminum removal for lithium iron phosphate cathodes has been systematically summarized in this paper,including the principles,advantages as well as disadvantages of various methods and development tendency of deep aluminum removal technology.Alkaline leaching,selective acid leaching,ion exchange and chemical precipitation all have been developed for deep aluminum removal and improvement of product quality.Among them,alkaline leaching method is efficient for removing aluminum,but there are some problems such as large amount of alkali consumption,high salt wastewater production and so on.Selective acid leaching has the advantages such as simple process and low cost,while it is need to be further improved for the low selectivity and poor effect of aluminum removal.The ion exchange method shows high efficient separation of iron and aluminum,while the high cost restricted the industry application.Chemical precipitation process become the guideline of the most promising technology for spent lithium iron phosphate cathode material because of simple operation,easy control and high aluminum removal effect.