硅溶胶制备纳米二氧化硅的工艺研究

以碱性硅溶胶和无机酸为原料,水和甲醇为反应介质,加入适宜的分散剂,反应体系在适宜的反应温度和pH值下反应一定时间,经过真空脱水干燥和超细筛网筛分得到稳定的纳米二氧化硅粉体。该方法的最佳工艺条件:反应温度50℃,pH=7.5~8.0,反应体系硅溶胶质量分数10%~20%,反应时间45 min。实验结果表明,制得纳米SiO2粉体的粒径为20~40 nm,比表面积大,分散性好,纯度在99%以上。该方法工艺简单,实用性强,适宜工业化生产。

Preparing Technics of Nano-silica with Silicon Sol

The preparation of nano-silica by chem-deposit method is carried out by using basic silicon sol and inorganic acid as materials.Upon considerable dispersant,reaction temperature and pH value of the reaction system,stable powder nano-silica is obtained through vacuum dehydrate dryness and fine sifting.The optimum conditions are describled as follow: the temperature is at 50 ℃,pH value at 7.5~8.0,the concentration of the reactants 10%~20%,and the reaction time 45 min.The result shows that the prepared nano-silica powder has good dispersivity with 20~40 nm of particle size and its purity exceeds 99%.This method is simply,applicable,and fits the industrial production.