METHOD OF OBTAINING FINE SILICA Russian patent published in 2012 - IPC C01B33/18 

FIELD: chemistry.

SUBSTANCE: invention relates to chemistry and the technology of inorganic silicon-oxygen compounds and can be used to produce fine silica from chlorosilane by-products from chemical-metallurgical chloride production of polysilicon and other metals and chemical production of organochlorosilanes. The method involves hydrolysis, subsequent condensation and deposition of particles in a solvent. The starting material used is chlorosilanes with functionality higher than 3, which, before hydrolysis, are alkoxylated with lower aliphatic alcohols C1-C3 in amount of 1.0-1.2 moles alcohol per 1 g-atom chlorine in chlorosilane. Further, the reaction mixture is diluted with a solution of alcohol with water in amount of 0.53-0.77 moles water per 1 g-atom alkoxy groups to until achieving concentration of deposited particles in the solvent of 14.0-25.2 wt %. The reaction mixture is boiled at 67-84°C for 2.5-3.5 hours.

EFFECT: simple technique of obtaining fine silica from high-functional chlorosilanes with output of 97,3-98,5 wt % of the load, improved quality and application properties of said silica, with simultaneous trapping of 89,4-96,7 wt % of the load of the formed gaseous hydrogen chloride.

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