合成条件对气相法白炭黑性能的影响

以甲基三氯硅烷、氢气、空气为原料,制备气相法白炭黑。考察了原料配比、骤冷介质温度、合成炉温度、原料气速对白炭黑的比表面积、平均粒径的影响。结果表明：甲基三氯硅烷、氢气的量之比与白炭黑的比表面积成反比;合成炉温、骤冷介质温度与白炭黑的比表面积、平均粒径成反比;原料气速与白炭黑的比表面积成正比,与平均粒径成反比。较佳工艺为：甲基三氯硅烷、氢气与空气的量之比为0.33∶0.47∶1,冷却介质温度80～90℃,炉温800～850℃,气体流速5～6 m/s。

Synthesis Conditions on Property of Fumed Silica

Fumed silica was prepared with CH3 Si Cl3,hydrogen gas and air as the raw materials. The effects of the ratio of the raw materials,the temperature of quenching medium and synthesis oven,and the gas velocity of the material on the specific surface area,and the average diameter of fumed silica were investigated. Results showed that the surface area of fumed silica is inversely proportional to the ratio of CH3 Si Cl3and hydrogen gas and the specific surface area and the average diameter d50 are also inversely proportional to the temperature of quenching medium and the oven,whereas the gas velocity is proportional to the specific surface area,but inversely proportional to the average particle size d50. The optimal process is with a ratio of methyl trichlorosilane,hydrogen gas and air of 0. 33∶ 0. 47∶ 1 at a cooling medium temperature of 80 ～ 90℃ and an oven temperature of 800 ～ 850℃,and the gas velocity of 5 ～ 6 m / s.