METHOD OF PRODUCING ULTRAFINE SILICON DIOXIDE POWDER Russian patent published in 2019 - IPC C01B33/18 C09C1/28 

FIELD: manufacturing technology.

SUBSTANCE: invention can be used in production of heat-insulating materials, dry construction mixtures, modified additives for concrete, production of optical fiber. Method of producing ultrafine powders of silicon dioxide involves preliminary drying and grinding of diatomite. 5 % sodium hydroxide solution is added into milled diatomite and treated with an electromagnetic field of 0.44 MHz for 10–15 minutes. Silicon acid is precipitated from the filtrate by adding a concentrated solution of hydrochloric acid, treating the precipitate, separation of silicon (IV) oxide by filtration, drying the precipitate is carried out on a filter, then in a petri dish in a drying cabinet at temperature of 90–120 °C.

EFFECT: invention allows to obtain silicon dioxide powder with dispersion of 50–100 nm of high degree of purity from inexpensive initial mineral silicon-containing material – diatomite, with minimum power consumption, optimized process scheme for industrial production, as well as increase output of ultradisperse silicon dioxide powder to 99,99 %.

1 cl, 1 ex