以试剂型硅藻土作为硅源,通过碱溶法提取活性硅可制备SiO2气凝胶材料.通过响应面中的Box-Behnken试验设计方法,以SiO2溶出率和水玻璃模数的加权平均值为评价指标,优化硅藻土制备水玻璃工艺,以获得最优的工艺参数.试验结果表明,当碱硅质量比为3:10,NaOH质量浓度为10%,反应温度为90%时,水玻璃模数与SiO2溶出率的加权平均值达到最大值79.91%.
Alkali solution method can be used to extract activated silica for preparing silica aerogels by adopting reagent level diatomite as a silica source. Box-Behnken experimental design method was adopted to optimize waterglass preparation process to obtain the optimum synthesis parameters, the weighted average of silicon dioxide dissolution rate and waterglass modulus were took as evaluation index. Experimental results showed the optimum condition as follows:alkali- silica ratio 3 : 10, alkalinity 10%, reaction temperature 90℃, weighted average of modulus and dissolution rate of silicon dioxide reached maximum 79.91%.