Process for producing precipitated white carbon black by silicon tetrachloride

Abstract

The invention belongs to a process for preparing white carbon black and in particular relates to a process for producing precipitated white carbon black by silicon tetrachloride. The process comprises the following steps: adding the silicon tetrachloride into 29 to 33 mass percent hydrochloric acid aqueous solution which contains a dispersant, controlling the temperature to between 28 and 45 DEG C for reaction to generate silica sol and chlorine hydride gas, standing and ageing the silica sol to form colloidal white flocculent sediment, filtering, separating and washing the sediment, and pelletizing and drying the sediment to obtain the precipitated white carbon black. The process has short flow, relatively simple production equipment and process control, and available raw materials, effectively utilizes the silicon tetrachloride, totally reclaims the product chlorine hydride, reduces the processing expense, the amount of waste acid and the environmental pollution, and has low production cost, wide application and large market capacity.

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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