摘要：采用新型微筛孔反应器,以硅酸钠和硫酸为原料,制备一次粒径为10 nm左右的水合二氧化硅沉淀,以乙醇为分散溶液,经喷雾干燥得到高蓬松二氧化硅颗粒,研究终点pH值、分散液中乙醇含量对二氧化硅孔特性的影响规律。结果表明,由于微筛孔反应器能够强化传质,提高过饱和度和均匀度,形成的一次颗粒粒径较小,有利于得到大的孔容和孔径;以乙醇为分散溶液,喷雾干燥可以保持大孔不塌陷,提高样品蓬松性。当终点pH值为8.5时,制备出比表面积为251.40 m²/g,孔容为2.14 mL/g和孔径为34.07 nm的二氧化硅颗粒。通过与气相法二氧化硅消光剂产品对比,发现二者孔容和孔径性能相近,但沉淀法制备成本大大降低。

关键词：无定形二氧化硅；喷雾干燥；微筛孔反应器；消光

Abstract：The amorphous silica precipitation consisted of primary particles with a diameter of 10 nm was prepared using sodium silicate and sulfuric acid as feedstocks in a micro-sieve reactor.These precipitation was dispersed in ethanol,silica with high fluffy was obtained after spray drying.It was found that because of the high mass transfer rate in this micro-reactor,the supersaturation ratio could reach very high,which was suitable for the formation of tiny primary particles.Fluffy was improved by spray drying,through rapidly evaporating solution of ethanol,porous flatting agent was prepared.When the final pH was equal to 8.5,the specific surface area of silica particles was 251.40 m²/g,pore volume of silica hydrated reached as high as 2.14 mL/g and the average pore size was 34.07 nm.Comparing the amorphous silica with commercial products prepared by fume method,it was found that their properties were close,however,this precipitation method greatly reduced the production cost.

Keywords：amorphous silica；spray drying；micro-sieve reactor；flatting