废旧磷酸铁锂正极粉制备磷酸铁、磷酸锂的研究

Research on the Recovery of Waste Lithium Iron Phosphate Cathode Powder for the Preparation of Iron Phosphate and Lithium Phosphate

以废旧磷酸铁锂正极材料(LFP)为原料,经碱洗后在硝酸溶液中溶解出Li、Fe、P有价元素。通过沉淀法分步制备磷酸铁、磷酸锂。探究了氧化剂用量、终点pH、NaOH质量分数等对制备磷酸铁的影响。利用X射线衍射仪、电感耦合等离子发射光谱仪、扫描电子显微镜对磷酸铁、磷酸锂的形貌及化学成分进行表征。结果表明,最佳制备条件为:氧化剂用量为2.5%、pH=2.5、NaOH质量分数为1%,所制备的磷酸铁经600℃焙烧后结晶度较高且为纯相物质,其形貌较为规整且分散均匀。

Waste LFP battery powder was used as raw material,and Li,Fe and P valent elements in it were dissolved in nitric acid solution after alkaline washing.Iron phosphate and lithium phosphate were prepared step by step by precipitation method.The effects of oxidizer dosage,endpoint pH,and NaOH concentration on the preparation of iron phosphate were explored.X-ray diffractometer,inductively coupled plasma emission spectrometer,and scanning electron microscope were used to characterize the morphology and chemical composition of iron phosphate and lithium phosphate.The experimental results showed that the optimal conditions for the preparation of iron phosphate were as follows:oxidant dosage of 2.5 wt%,pH=2.5,NaOH concentration of 1%,and the prepared iron phosphate was more crystalline and pure phase after roasting at 600℃,and its morphology was more regular and uniformly dispersed.