Synthesis of precipitated silica from sodium silicate solution by carbonation method

Abstract

A method was proposed for the preparation of silica powders using sodium silicate as the silica source and carbon dioxide and hydrochloric acid as precipitating reagents. The effect of reaction temperature (20, 40, 60, and 80 °C) and SiO2 concentration in sodium silicate solutions (4, 6, 8, and 10 %) on silica morphology, dibutyl phthalate absorption, aggregate size distribution, and dispersion ability (agglomerates fragility) were investigated. The best properties of silica powder were achieved at reaction temperature 40 °C and SiO2 concentration 8 %. The properties of the silica sample obtained at optimal conditions were compared with properties of high-quality commercial silica used as rubber reinforcing filler. Also, the vulcanization characteristics and mechanical characteristics of rubber composites containing these two silica fillers were investigated. It was found that silica filler with excellent properties can be produced using the proposed method, while by tuning temperature and precursor concentration, the silica properties that are important for its reinforcing potential may be closely controlled.