METHOD OF PRODUCING MONODISPERSE NANOSILICA HYDROSOL FOR MAKING CONCRETE Russian patent published in 2019 - IPC C01B33/14 B82Y40/00 B82B3/00 

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. Hydrosol of monodisperse nanosilica is obtained using sol-gel synthesis. In the reaction mixture, ammonia is used as a catalyst for hydrolysis of tetraethoxysilane, ethanol as a solvent, and polysorbate is also added as a stabilizer. Ethanol is distilled off while heating while simultaneously feeding water. Polysorbate is removed from the obtained hydrosol of nanosilica by oil flotation with the addition of a light aliphatic saturated hydrocarbon with density of less than 700 kg/m³ and a boiling point in region of 40–70 °C and settled until complete separation into two fractions. Lower fraction is hydrosol of monodispersed nanosilica, and the upper fraction is a mixture of a light aliphatic limit hydrocarbon and a polysorbate which is separated by distillation for reuse.

EFFECT: disclosed invention enables to obtain hydrosol monodisperse nanosilica with low amount of ethanol, not more than 0,1 %, ready for use in making concrete.

1 cl, 3 tbl, 2 ex