METHOD FOR PRODUCTION OF AMORPHOUS SILICON DIOXIDE IN GRANULE FORM Russian patent published in 2023 - IPC C01B33/193 B01J2/02 

FIELD: silicon production.

SUBSTANCE: invention relates to the production of amorphous silicon dioxide in the form of granules to obtain a product with improved properties. A method for obtaining amorphous silicon dioxide in the form of granules is proposed, which consists in preparing and purifying a sodium silicate solution with subsequent dissolution of settled flakes of undissolved sodium silicate at the first stage, at the second stage, the formation of the substrate (a), during which 18–20 m³ suspension of sodium silicate with a density of 1.130-1.200 g/cm³ and a temperature of 20-95°C and 5-6 m³ of sodium sulphate solution with a density of 1.03-1.06 g/cm³, the neutralization process (b), which consists in supplying dilute sulfuric acid to the substrate in the reactor at a feed rate of 14 to 20 m³/ h for 16-25 min, the temperature in the reactor at this stage is maintained at 80-88°C, then from 16-25 minutes to 47-87 minutes, sulfuric acid is fed into the reactor, the feed rate is 6-15 m³/h, and from 45-80 minutes to 79-110 minutes, a suspension of sodium silicate is fed into the reactor at a feed rate of 2 0-2.8 m³/h, at the same time, sulfuric acid is supplied simultaneously with sodium silicate, the feed rate is 2.0-2.8 m³/h, after 79-110 minutes the supply of sodium silicate stops, from 79- 110 to 96-130 minutes, the sulfuric acid supply rate is 2.2-3.0 m³/h, the suspension is averaged using the paddle mixer (c), at the third stage, the suspension is filtered, the sediment is washed and repulped, and at the fourth stage, suspension of silicon dioxide is dried and granulated, whereas the suspension is fed from the collection tank into the pressure tank of the dryer, from where it flows by gravity to the disk of the spraying mechanism, where due to its rotation at a speed of n = 4000-8000 rpm in the presence of a drying agent, the suspension is sprayed, whereas drying the suspension in the dryer occurs in the temperature zone 500-650°C by a short-term, within 5-8 seconds, stay of granules in it, then the amorphous silicon dioxide obtained in the form of microgranules settles in the cone of the dryer and is fed into the pneumatic transport system, from where it is fed to the cyclones by a fan, and the amorphous silicon dioxide that has settled inside the cyclones in the form of microgranules is supplied for packaging.

EFFECT: preservation of the original structure of the particles and the homogeneity of amorphous silicon dioxide, as well as the high purity of the resulting product.

1 cl, 4 dwg, 1 ex