The Study On Key Technology For Production Of Food-Grade Silica Using Silicon Tetrachloride By-Produced From Polysilicon

Silica is an important chemical products, mainly used as a substitute for carbon black, it is widely used in the rubber industry crosslinking reinforcing agent, ink, paint industry, thickeners, dispersants, thixotropic agents, as well as the food industry additives. The current domestic production of silica to precipitate more production, more low-end products for food-grade silica products mainly rely on imports.At the same time, with the rapid development of pHotovoltaic industry, polysilicon sound processing and use is becoming an increasingly prominent issue in the production of by-product of silicon tetrachloride, and even become a bottleneck in the development of domestic polysilicon.To explore the method of dealing with by-product Si Cl4, this paper is about the research on using precipitation process to prepare a food-grade silica particles which is the same as the gas-pHase process, through a small pilot study exploiting the starting materials of by product SiCl4 which was produced by sodium silicate and polysilicon. These factors of the reaction temperature, sodium silicate concentration, PH value of the solution, surface active agents were detailed studied on the effect on the particle size of silica products under different conditions.On the basis of a small pilot study, by precipitated silica production process improvements, this paper studied new technology process of producing high-quality precipitated silica as the starting materials of sodium silicate and polysilicon under mild reaction conditions.Through scientific amplification and orthogonal study the approach taken, every single factor of a small pilot study has been studied by the combination methods. Through the SPSS variance, we determine the different factors on the impact strength of the product size under the moderate test conditions, obtaining the optimal reaction conditions combination to produce qualified food-grade silica products. By using different instruments test product at the same time, the products was sent to the national authorities and sent to users to get the praise.By combining with the results and the situation of chemical industry in Hunan and Jiangxi provinces, this study also proposed ten thousand tons / year production process. Furthermore, the feasibility study of producing food-grade silica by tetrachloride silica by-product of the production was designed, which can obtain good economic social benefits after industrialization.