利用低品位红土镍矿制备纳米二氧化硅粉体

Preparation of nano silica powder from low grade laterite nickel ore

以低品位红土镍矿碱式水热过程中产生的硅酸钠滤液为原料,采用化学沉淀法合成纳米二氧化硅粉体。考察了硫酸浓度、熟化温度、熟化时间、搅拌速度、表面活性剂PEG种类对二氧化硅粉体粒径的影响。通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和激光粒度分析仪对制得的二氧化硅的物相、结构、形貌和粒径进行了表征。结果表明,反应的最佳条件为:硫酸浓度10%、熟化温度70℃、熟化时间1 h、搅拌速度600 r/min。在最佳条件下,当表面活性剂种类选用PEG 400时,制得的二氧化硅粒径相对较小,约为200 nm,球形度较好。

Nano silica powder was synthesized by chemical precipitation method from sodium silicate filtrate produced in the alkaline hydrothermal process of low grade laterite nickel ore.The effects of sulfuric acid concentration,curing temperature,curing aging time,stirring speed and surfactant PEG type on the particle size of silica were investigated.The phase,structure,morphology and particle size of silica prepared were characterized by X-ray powder diffraction(XRD),scanning electron microscope(SEM)and laser particle size distribution.The optimum conditions were determined as follows:sulfuric acid concentration 10%,curing temperature 70℃,curing time 1 h and stirring speed 600 r/min.Under the best conditions,when the surfactant type PEG 400 is selected,the size of silica prepared is relatively small,about 200 nm,and the sphericity is good.