Process for producing precipitated white carbon black from silicon tetrachloride

Abstract

The invention belongs to a preparation process of white carbon black, in particular to a process for producing precipitated white carbon black from silicon tetrachloride. Add silicon tetrachloride to the hydrochloric acid aqueous solution with a mass concentration of 29-33% containing a dispersant, control the temperature at 28-45°C to react to generate silica sol and hydrogen chloride gas, and the silica sol will form colloidal White flocculent precipitate, the precipitate is separated by filtration, washed, granulated and dried to obtain precipitated white carbon black. The present invention has short process flow, relatively simple production equipment and process control, and easy-to-obtain raw materials; silicon tetrachloride is effectively utilized, and the product hydrogen chloride is completely recovered, thereby reducing treatment costs, reducing the amount of waste acid, and reducing environmental pollution; The production cost is low, the application is extensive, and the market capacity is large.

Description

(1) Technical field [0001] The invention belongs to the preparation process of white carbon black, in particular to a process for producing precipitated white carbon black from silicon tetrachloride. (2) Background technology [0002] At present, white carbon black is generally produced by using sodium silicate, silicon tetrachloride, ethyl orthosilicate, etc. as silicon sources. There are two production processes: precipitation method and gas phase method: silicic acid is generally used in the production of white carbon black by precipitation method. Salt (usually sodium silicate) and inorganic acid (usually sulfuric acid) neutralization precipitation reaction method to produce; vapor phase production of white carbon black is the use of silicon chloride (silicon tetrachloride or methyl trichlorosilane) It is produced by high-temperature hydrolysis in a mixed air and hydrogen gas stream, and a large amount of low-purity hydrogen chloride is produced as a by-product during pr...

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Problems solved by technology

The silicon tetrachloride used in gas phase production of white carbon black mostly originates from the silicon tetrachloride by-product of trichlorosilane and polysilicon industry, but there are following problems: 1) the by-product of trichlorosilane and polysilicon industry is tetrachloride The amount of silicon is large, and the ability to produce white carbon black by the gas phase method is limited, so it cannot be processed effectively; 2) The process of producing white carbon black by the gas phase method is complicated and the cost is high, and at the same time, a large amount of low-purity hydrogen chloride by-product can only be made into waste hydrochloric acid , resulting in greater waste and environmental pollution; 3) The fumed silica is expensive, the scope of use is narrow, and the market capacity is small. Carbon black is cheap and widely used, and its market capacity is dozens of times that of fumed silica

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