METHOD OF PRODUCING SODIUM SILICOFLUORIDE Russian patent published in 2015 - IPC C01B33/10 

FIELD: chemistry.

SUBSTANCE: method includes reacting hydrofluorosilicic acid and a mixture of sodium-containing compounds, separating the product, washing and drying, wherein the mixture of sodium-containing compounds used is an aqueous solution with density of 1.1-1.13 g/cm³ of a mixture of sodium chloride, sulphate and hydroxide, taken in weight ratio of (6-12):(0.5-2):1; the mixture of sodium-containing compounds is taken in amount of 110-120% of the stoichiometrically required amount for reaction with hydrofluorosilicic acid, and the reactants react via a continuous method at 0-50°C for 15-30 minutes to obtain a suspension; the suspension is then settled; the mother solution is separated by decantation to obtain pulp; the pulp is diluted with water in volume ratio of 1:1 and filtered; the product precipitate is washed with water and dried. The mixture of sodium-containing compounds used can be caustic soda production wastes which are pre-diluted with water in volume ratio of 1:1.

EFFECT: obtaining an easy to filter precipitate and low corrosive activity of the mother solution.

2 cl, 1 dwg, 1 tbl