磷酸铁是合成磷酸铁锂电池正极材料的主要原料，目前多采用硫酸亚铁和磷酸盐共沉淀方法制备。硫酸体系内共沉淀获得的磷酸铁中硫杂质含量较高，目前采用水洗方式脱除，吨磷酸铁洗水用量需60~100吨，硫酸盐废水处理成本高。为从源头削减磷酸铁脱硫过程产生的大量废水，根据硫酸盐高温分解的性质，提出磷酸铁高温煅烧脱硫新方法，开展了热力学可行性计算与高温煅烧脱硫动力学研究。结果表明，磷酸铁中硫元素主要以硫酸根形式存在，高温煅烧可有效促进含硫杂质分解，温度越高，脱硫效果越好。高温煅烧脱硫过程反应动力学级数为2，活化能为88.075 kJ/mol，属于化学反应控制。在温度1173 K、煅烧时间10 min的条件下，磷酸铁中硫杂质含量可降至0.01wt%以下。

Iron phosphate is the main material for the synthesis of lithium iron phosphate battery cathode material, which is mainly produced by co-precipitation method of using ferrous sulfate and phosphate salt. The sulfur content in the iron phosphate prepared by the co-precipitation process in the sulfate system is high, which has to be removed by washing with large amount of water of around 60~100 tons per ton of iron phosphate, bringing a huge burden of sulfate-bearing wastewater treatment. To reduce the amount of wastewater from the source, this research proposed an alternative way for desulfurization by high-temperature calcination based on the feature of sulfate decomposition at high temperatures. The thermodynamic feasibility and kinetics of the desulfurization were studied. The results showed that the sulfur in ferric phosphate existed in the form of sulfate, which can be effectively removed by high-temperature calcination. A higher temperature was preferred for a more satisfactory desulfurization efficiency. Kinetic study uncovered that the desulfurization reaction order was 2, and the activation energy was 88.075 kJ/mol, indicating a chemical reaction control mode. The sulfur content in iron phosphate can be reduced to less than 0.01wt% by calcining at 1173 K for 10 min.