AMORPHOUS SILICON DIOXIDE SYNTHESIS METHOD Russian patent published in 2010 - IPC C01B33/12 

FIELD: chemistry.

SUBSTANCE: invention can be used to produce finely dispersed silicon dioxide used as mineral filler. The silicon-containing starting material used is natural rocks with high content of bonded amorphous silica of up to 70-75 %. The material is ground in a vibrating mill with ceramic or agate spheres to obtain a fraction with fineness of 10 mcm. In order to obtain amorphous dioxide with given specific surface area, treatment is carried out with an alkaline agent whose concentration is selected in accordance with a nomogram. Silicon dioxide is deposited with mineral acid through its initial supply in an amount which provides a mixture with pH 12, holding the mixture while stirring continuously for 10-15 minutes and then adding acid in amount which provides a mixture with pH 10, holding the mixture once more while stirring continuously for 10-15 minutes and final addition of acid to obtain a mixture with pH 7. Before each addition of acid, water is also added to the liquid phase in amount of 8-10%.

EFFECT: invention enables to obtain silicon dioxide with specific surface area of 150-800 m²/g.

4 cl, 1 dwg, 1 tbl, 1 ex