电池级超微细磷酸铁的制备

为了探索一种低成本的磷酸铁合成工艺,以硫酸亚铁为原料,经过硫酸亚铁氧化、碱式磷酸铁沉淀、碱式磷酸铁转化制备出电池级超微细磷酸铁.研究了硫酸亚铁氧化、碱式磷酸铁沉淀、碱式磷酸铁转化反应过程中反应温度、加料时间、磷酸浓度等因素对磷酸铁产品质量的影响.通过试验得到了合成磷酸铁的最佳工艺条件：氧化反应过氧化氢加料量为标准量的120%,加料时间50min,沉淀反应温度40℃;磷酸铵加料时间40min,转化反应温度90℃,磷酸浓度0.5mol/L.在此最佳工艺条件下制备出了平均粒径小于3.0μm的电池级超微细磷酸铁,元素分析表明产品中金属杂质含量均小于0.005%,硫含量小于0.022%,且磷铁比为1.01,产品磷酸铁纯度较高.X射线衍射分析结果表明未经高温处理的产品是一种无定形微细颗粒,而经过600℃高温煅烧后的产品结晶度高,晶型完美.

Preparation of battery-grade ultra fine iron phosphates

To explore a low cost synthesis process of iron phosphates,preparation of battery-grade ultra fine iron phosphates is discovered with ferrous sulfate as the raw material by ferrous sulfate oxidation reaction,basic iron phosphate precipitation reaction and basic iron phosphate conversion reaction.Influences of reaction temperature,feeding time of hydrogen peroxide and ammonium phosphate,feeding quantity of hydrogen peroxide and concentration of phosphoric acid etc.on the product quality were discussed.The optimal process conditions are that hydrogen peroxide feeding quantity is 120% and feeding time is 50 mins in oxidation reaction,reaction temperature is 40 ℃;ammonium phosphate feeding time is 40 mins in precipitation reaction,reaction temperature is 90 ℃ and concentration of phosphoric acid is 0.5 mol/L in conversion reaction.Battery-grade ultra fine iron phosphates with particle size less than 3.0 μm can be prepared under the optimum conditions,elemental analysis reveals that the content of metal impurities is less than 0.005%,sulphur content is less than 0.022%,and n（P）/n（Fe） is 1.01;the iron phosphates is highly pure product.X-ray diffraction test results show that the product without high-temperature treatment is amorphous ultra fine particles,and the product after being treated under high temperature of 600 ℃ has high crystallinity,and crystal is very perfect.