Abstract: In the reaction process of silica by oil of vitriol precipitation, oil-absorbed value, bulk density, size of amorphous silica were studied by reaction time and reaction temperature. The result shows that with the increasing of the reaction time, the oil-absorbed value increased first and decreased then, bulk density decreased first and increased then, the size of amorphous silica decreased first and increased then. With the increasing of reaction temperature, the oi-absorbed value increased first and decreased then, bulk density decreased first and increased then, the size of amorphous silica gradually decreased. Through the comprehensive analysis of factors, the best reaction temperature is 85 ℃, the best reaction time is 20 min. Silica is prepared for rubber reinforcement.

Key words: precipitation method%silica%rubber