METHOD FOR PRODUCING AMORPHOUS SILICON DIOXIDE AND AMORPHIZED PRODUCT OBTAINED ACCORDING TO METHOD Russian patent published in 2017 - IPC C01B33/12 B82Y99/00 

FIELD: chemistry.

SUBSTANCE: method for producing amorphous silicon dioxide from rice husk ash is described, which is processing the feedstock natural moisture in the reactor of the oxygen or air-water mixture with obtaining of furnace gasificate and with excepting diffraction peaks of crystalline silica in the diffraction pattern from RHA (rice husk ash) and separating the impurities and dimensional agglomerates in the air-jet separator, downloading the product automatically in the acid cleaning station, which is further washed with purified water. After washing to a neutral wash water pH, the product is sent to an alkaline treatment module where a KOH solution of the optimum concentration is added and heat treated until the silicon-containing portion of the RHA is completely dissolved. Mineral acid is added to its resulting alkaline solution, the reaction mixture is warmed up with a gradual lowering of pH to neutral values, at which there is a drop of white flaky or a gelatinous precipitate that weathered, centrifuged, separated from the solution and washed with distilled water until a neutral wash water pH. The amorphized product obtained according to the method, is an amorphous silica of snow-white colour in the form of the single face plates of a nanometer size, articulated in different ways, the size of this type of grain is 2-12 microns with a possible further electrostatic conglomeration characterized by loss of moisture at 105°C 2-8 wt %, the mass loss up to 1000°C 4-14%, pH of the slurry to 5.5-8 and the content of SiO₂ in the calcined product of more than 99.99 wt % and heavy metals and chloride - lower limits of detection on the surface area of 180-360 m²/g.

EFFECT: method is developed that allows to obtain a product with an active surface demonstrating different particle sizes, their morphology and density.

3 cl