综合利用钛铁矿制备二氧化钛、钛酸锂和磷酸铁锂

Preparation of titanium dioxide,lithium titanium oxide and lithium iron phosphate from ilmenite

以钛铁矿为原料,经机械活化-盐酸浸出得到水解钛渣和富铁浸出液;用H2O2将水解钛渣中的Ti配位溶出,得到配位浸出液,并以其为反应物制备纳米级片状的过氧钛化合物;该过氧钛化合物经洗涤、煅烧制备得到纳米级片状的TiO2,其纯度高达99.31%(质量分数)。将过氧钛化合物与Li2CO3混合,球磨后煅烧合成性能优良的锂离子电池负极材料Li4Ti5O12。以富铁浸出液为原料,经选择性沉淀制备含少量Al和Ti的FePO4.xH2O,并以其为前驱体制备了Al-Ti掺杂的LiFePO4。该LiFePO4在1C和2C倍率下的首次放电比容量分别达151.3和140.1(mA.h)/g,循环100次之后容量无衰减。该方法也可用于钛白粉副产品硫酸亚铁的回收利用,制备性能优异的LiFePO4。

Titanium hydrolysate and iron-rich lixivium were obtained from the ilmenite by mechanical activation and hydrochloric acid leaching.By using H2O2 as a coordination agent,titanium was leached from the titanium-slag and a coordination lixivium was obtained.A nano-sized platelike peroxo-titania compound was prepared by heating the coordination lixivium.The peroxo-titania compound was washed and sintered,then a nano-sized platelike TiO2（99.31%,mass fraction） was obtained.Li4Ti5O12 was synthesized by sintering the mixture of peroxo-titania compound and Li2CO3,the sample shows a good electrochemical performance as an anode material for the lithium-ion batteries.A selective precipitation method was used to synthesize FePO4·xH2O precursor from the iron-rich lixivium.The Ti-Al doped LiFePO4 was prepared using the FePO4·xH2O as the starting material.The as-prepared LiFePO4 exhibits a first discharge capacity of 151.3 and 140.1（mA·h）/g,respectively,and shows no capacity fading after 100 cycles.Also,this method was used to synthesize the high-performance LiFePO4 from the ferrous sulfate waste slag produced by the titanium dioxide industry.