METHOD OF PRODUCING AMORPHOUS SILICON DIOXIDE FROM PROCESSING WASTES OF HYDROFLUOROSILICIC ACID AND PRODUCTION OF ALUMINUM FLUORIDE Russian patent published in 2022 - IPC C01B33/12 

FIELD: technological processes.

SUBSTANCE: invention relates to a method of producing amorphous silicon dioxide from processing wastes of hydrofluorosilicic acid and production of aluminum fluoride, involving treatment of silica gel with a solution of mineral acids, separation, washing and drying, wherein the silica gel is dried at temperature of 100 to 120 °C for 2 to 4 hours, followed by pretreatment of the silica gel with a solution of sulfuric acid with concentration of 0.1 wt.% up to 0.5 wt.% in weight ratio of l:s from 5:1 to 20:1, then heated to temperature of 25 to 100 °C with continuous stirring for 0.1 to 2 hours, to obtain a solid phase — amorphous silicon dioxide, which is dried in air for at least 48 hours at temperature from 20 to 25 °C, then separated into two fractions with particle size from 2 to 50 mcm and from 50 to 150 mcm and liquid phase, which is sent for recycling.

EFFECT: described is a method of producing amorphous silicon dioxide.

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