METHOD OF PRODUCING HYDROGEN FLUORIDE Russian patent published in 1995 - IPC

FIELD: inorganic chemistry. SUBSTANCE: solution of sulfuric acid, hydrofluoric acid, fluosilicic acid and water is added to fluorspar at the mass ratio CaF₂:H₂SO₄:HF:H₂SiF₆:H₂O, 1:(0.25-0.60):(0.02-0.10):(0.01-0.07): (0.06-0.15). Then deficient quantity of sulfuric acid is added to the mixture among them as oleum of the total feeding sulfuric acid (105-110% of stoichiometric) which is necessary for fluorspar decomposition with sulfuric acid. Mixture is fed to the furnace where process is carried out at 180-220 C. Exhausted HF is purified in the gaseous phase by absorption, condensation and rectification, and solid phase is neutralized and calcined at 320-350 C. The yield of product is 95.0-95.2% Fluorine loss with by-side calcium sulfate is 0.8-1.0% Invention ensures to increase the yield of product from 94.1% to 95.0-95.2% due to decrease of fluorine loss with calcium sulfate from 2% to 0.8-1.0% EFFECT: improved method, increased yield of product. 2 cl, 1 tbl