A production process and device of nano fumed silica

Abstract

The invention discloses a production process and device for efficiently producing nano fumed silica. The production process specifically comprises the following steps: gasifying chlorosilane in a corresponding preheater, further feeding into a mixer, mixing the processed chlorosilane with hydrogen and air, heating to 100 DEG C or greater, feeding into a sealed furnace through a reactor at a flowing speed of 30-100m / s, performing combustion hydrolysis reaction, controlling the reaction temperature to be 1000-1800 DEG C, and performing process treatment such as aggregation, separation and deacidification on obtained fumed silica particles, thereby obtaining a fumed silica product. By controlling the inner diameter of a fitting reactor nozzle and the size of the sealed furnace, the single-line production capacity is increased; due to adoption of the sealed furnace equipment and processes, the condition that the reactions are not affected by external temperature differences and humidity can be guaranteed, the specific surface area standard deviation of the obtained fumed silica at different points is smaller than 10, the sieve residues of 45 microns are less than 100ppm, the product quality and the production stability are improved, data controllability is ensured, and the on-stream time is prolonged by 120 days or more.

Description

technical field [0001] The invention belongs to the field of nanometer powder materials, and in particular relates to a gas-phase silicon dioxide production process and equipment thereof. Background technique [0002] Fumed silica, also known as fumed silica, is an extremely fine nano-scale amorphous silica obtained by high-temperature hydrolysis of halosilane in an oxygen-hydrogen flame, with small particle size, uniform particle size distribution, and large specific surface area. , with high surface activity. Fumed silica can be used in polymer composite materials, silicone rubber, coatings, electronic packaging materials, colloids, batteries, ceramics, plastics, glass fiber reinforced plastics, sealants, papermaking, food, cosmetics, gel coat resins, chemical mechanical polishing and other industries. It can play the role of reinforcement, thickening, thixotropy, extinction, etc., and has a wide range of uses. [0003] At present, the domestic fumed silica has the follo...

AI Technical Summary

Problems solved by technology

[0004] 1. The single-line production capacity is low. Although the current domestic fumed silica production enterprises have a certain scale, the single-line gauge generally does not exceed 1,000 tons per year. The scale is small and the market demand is large, resulting in a shortage of products;

[0005] 2. The quality of the product fluctuates greatly. The downstream customers of fumed silica generally report that the use of domestic fumed silica fluctuates greatly during the use process. The thickening and reinforcing effects are good and bad. It is necessary to change the formula at any time, which causes certain troubles to the production. Compared with foreign products, the gap is obvious;

[0006] 3. The types of technologies are single. In the production process of fumed silica, many manufacturers often use a single raw material for production, and production is often constrained by raw material suppliers

[0008] 1. Chlorosilane is very easy to hydrolyze, and the high water content of raw material air and hydrogen will cause hydrolysis of chlorosilane, white spots and fluctuations in specific surface area in the product;

[0009] 2. The reaction process is easily affected by the outside world. The structure of the existing fumed silica production process reaction furnace is mainly an open furnace. The outside air is sucked into the reaction furnace to participate in the reaction. As the air humidity and temperature change, the product quality will change accordingly. Changes occur, and the process parameters are uncontrollable;

[0010] 3. The compounding of raw materials is difficult. Chlorosilane has a large difference in the activity of raw materials and a large fluctuation in boiling point due to the different proportion of silicon and chlorine. Conventional static mixing and reboiling is prone to the problem of inhomogeneous mixed gas phase, and the appearance of the product will deteriorate. The mixing time If it is not used for too long, it will easily cause the concentration gradient of the raw materials in the tank to change, and it needs to be recycled before it is put into production, which will increase the cost and cause great inconvenience to the production.

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