High-dispersion nano silicon dioxide preparation method

Abstract

The invention discloses a method to prepare high-disperse nano SiO2, imputting O2-H2 organic halogen silane in a certain proportion into reaction room to make burning reaction, at the same time inputting a protective gas, vapor and inert gases, adopting the produced water and heat to make high-temperature hydrolytic condensation reaction and making the late process such as aggregative gas-solid separation deacidification on the reaction product to obtain it, primary particle dimaeter 7-40 nm, ratio surface area 100-400 m2 / g, pH value 3.8-4.5, SiO2 receiving rate >99%.

Description

Technical field [0001] The invention relates to a preparation method of highly dispersed nano silicon dioxide. Background technique [0002] Due to its unique physical and chemical properties, highly dispersed nano-silica is widely used in rubber and plastic coatings, paint inks, adhesives, cosmetics, medicine, agriculture and other fields, and plays a role in reinforcement, thickening, thixotropy, extinction, and anti-settling , anti-sagging and anti-aging effects. At present, the methods for preparing highly dispersed nano-silica can be divided into two types, one is the wet method, which uses a silicate solution (such as sodium silicate) to hydrolyze under acidic or alkaline conditions, and then undergoes a series of post-treatments. The process yields silica, also known as precipitated silica. The other is the dry method, using organosilicon halides (such as silicon tetrachloride, methyltrichlorosilane, etc.) Process to obtain silica, also known as fumed silica or fum...

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Problems solved by technology

For specific methods, refer to U.S. Patents 418964, 3954945 and 4048290 and Chinese Patent CN 1043633C, etc. However, in traditional methods, fumed silica particles are easy to deposit on the reaction chamber wall, and as time goes on, the deposited silica particles will make The size of the reaction chamber becomes smaller, which in turn affects the geometric size and shape of the reaction flame, and ultimately affects the uniformity and quality of the product. Sometimes during the production process, the reaction chamber must be stopped and mechanically cleaned, which affects the continuity of production.

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