低品位磷铁矿浸出液制备掺杂型磷酸铁

    Preparation of Doped Iron Phosphate by Acid Leaching Solution of a Low-grade Phosphate Iron Ore

    • 摘要: 【目的】为解决酸浸低品位磷铁矿对环境的污染问题,降低合成磷酸铁的生产成本,实现资源综合利用;【方法】以低品位磷铁矿为原料,通过酸浸法和共沉淀法,采用低品位磷铁矿酸浸液制备掺杂型磷酸铁作为磷酸铁锂电池的前驱材料。利用XRD、SEM-EDS、粒度分析仪、原子吸收、碳硫分析仪等检测手段,系统研究了不同实验参数对掺杂型磷酸铁的组分、形貌、粒度等因素的影响。【结果】较佳酸浸条件为起始硫酸浓度0.5 mol/L、酸浸时间30 min、搅拌速度300 r/min、液固比4∶1、酸浸温度25 ℃;合成掺杂型磷酸铁的较佳条件为pH值2.0、磷铁比1.5、反应时间240 min、反应温度85 ℃;将样品在800 ℃焙烧后得到的掺杂型磷酸铁分布均匀,无大量团聚现象;SEM谱图点分析显示,产物中除了FePO4,还含有部分AlPO4等掺杂元素;样品球磨后粒径D50为2.695 μm,符合电池级磷酸铁的行业标准,使用柠檬酸清洗15次以后,硫含量低于0.04%。【结论】制备的掺杂型磷酸铁可以作为磷酸铁锂电池的前驱材料。

       

      Abstract: Objective To address the environmental pollution caused by acid leaching of a low-grade phosphate iron ore, reduce the production cost of synthetic iron phosphate, and achieve comprehensive utilization of resources, Method doping-type iron phosphate was prepared by an acid leaching and co-precipitation method using low-grade phosphorite as the raw material and precursor of a lithium iron phosphate battery. The effects of different experimental parameters on the composition, morphology, and particle size of doped iron phosphate were systematically studied using XRD, SEM-EDS, particle size analysis, atomic absorption, and carbon sulfur analysis. ResultThe optimum acid leaching conditions were as follows: initial sulfuric acid concentration of 0.5 mol/L, acid leaching time of 30 min, stirring speed of 300 r/min, liquid-solid ratio of 4:1, and acid leaching temperature of 25 ℃. The optimum conditions for the synthesis of doped iron phosphate were a pH value of 2.0, phosphorus iron ratio of 1.5, reaction time of 240 min, and reaction temperature of 85 °C. The doped iron phosphate obtained after the calcination of the sample was evenly distributed without a large amount of agglomeration. After analyzing the SEM spectrum points, it is known that the product contains some doping elements, such as AlPO4 in addition to FePO4, and the particle size D50 of the sample after ball milling is 2.695 μm, which accords with the industry standard of battery-grade iron phosphate. After washing with citric acid 15 times, the sulfur content was < 0.04%. ConclusionDoped iron phosphate can be used as a precursor material for lithium iron phosphate batteries with a good electrochemical performance.

       

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