硅溶胶制备纳米二氧化硅的工艺研究

Preparing Technics of Nano-silica with Silicon Sol

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45min。实验结果表明，制得纳米SiO2粉体的粒径为20-40nm，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。

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.