Preparation of Iron Phosphate Battery Materials from Industrial Ferrous Sulfate Waste by Liquid Phase Method

Sulfuric acid method is a critical method to prepare rutile and anatase titanium dioxide. In the preparation process, acid leaching is accompanied by a large amount of iron-containing solid waste, represented by ferrous sulfate waste. If these solid wastes are stored directly without proper treatment, they will cause massive environmental damage and a lot of iron resources waste. The impurity removal and high added value utilization of ferrous sulfate had been studied deeply. Based on those studies, separation impurities from ferrous sulfate waste with various phosphate radical precipitation separation method was further explored. And a new process of preparing iron phosphate (FePO4) electrode material by liquid phase precipitation method was proposed to recover Fe from solid waste. Results showed that recovery of Fe in solid waste achieved 92%; moreover, removal rates of Ti, Mg, and Mn are higher than 95.3%, 78.4%, and 89.2%, respectively. The prepared iron phosphate reached the industrial battery grade (HG/T 4701-2014) standard by liquid phase reaction. The process realized efficient recovery of iron from solid waste and high value-added utilization of iron-containing solid waste.