Study on Preparation Technology of Ultrafine Silica by Silicon Tetrachloride Gas Phase Hydrolysis Method

The ultrafine silica was prepared from silicon tetrachloride by gas phase hydrolysis method in this paper.Several reaction factors such as the ventilation rate of silicon tetrachloride,concent of Na2SiO3 and reaction temperature on the physical and chemical properties of product were investigated.The results show that the optimum conditions are confirmed as follows: ventilation rate of silicon tetrachloride is 150 mL/min,concent of Na2SiO3 is 13% and reaction temperature is 70 ℃.Under the optimum conditions,the product is amorphous silica and characterized in various aspects as follows: DBP is 2.57 mL/g,specific surface area is 115.49 m2/g,silica content(dry basis) is 99.06%,apparent density is 0.11 g/mL and particle size(d50) is 6.5 μm.