METHOD FOR PRODUCING AMMONIUM SILICON FLUORIDE Russian patent published in 2017 - IPC C01B33/10 

FIELD: chemistry.

SUBSTANCE: method for producing ammonium silicon fluoride from the fluorosilicic acid solution containing silicon dioxide, includes the separation of the initial solution into two parts, the direction of the first part containing the calculated amount of acid for decomposition by means of ammonia water at the pH of 8-9 and the temperature of 50-90°C with separating the silicon dioxide precipitate formed from the solution and feeding a filtrate representing the ammonium fluoride solution, into the remaining part of the fluorosilicic acid solution. The resulting solution is neutralized with ammonia water solution, and the neutralized ammonium silicon fluoride solution is dehydrated in a fluidized bed of an inert material at the temperature of 120-180°C. The fluorosilicic acid amount directed to decomposition by means of ammonia water is calculated based on the acid concentration and the silicon dioxide content in the initial solution as per the proposed mathematical relationship.

EFFECT: improving the quality of the desired product.

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