METHOD FOR PRODUCING HYDROGEN FLUORIDE FROM AQUEOUS SOLUTION OF HEXAFLUOROCROMYMIC ACID Russian patent published in 2018 - IPC C01B7/19 C01B33/18 C01B13/22 

FIELD: technological processes.

SUBSTANCE: invention relates to the technology of inorganic substances. Method for producing hydrogen fluoride from an aqueous solution of hexafluorosilicic acid includes mixing of mentioned solution with a solution of sulfuric acid, subsequent desorption of hydrogen fluoride from resulting sulfuric acid solution, its treatment with sulfuric acid, condensation from unabsorbed gases of anhydrous hydrogen fluoride. Solution of hexafluorosilicic acid is mixed at a temperature of 100–190 °C with sulfuric acid with concentration of at least 71 wt. % in amount of at least (0.7⋅(100-a))/(x-70) grams per gram of solution of hexafluorosilicic acid in solution, where x is concentration of sulfuric acid, %, and a is concentration of hexafluorosilicic acid solution, %. Resulting reaction product gases are burned in flame of a hydrogen-containing fuel and oxygen-containing oxidant. Solid silicon dioxide is isolated from reaction products. Remaining products are cooled and a condensed anhydrous hydrogen fluoride is recovered.

EFFECT: invention allows to reduce the amount of generated waste, as well as costs of carrying out hydrogen fluoride production process.

1 cl, 1 dwg, 2 ex