At present, the production of hydrofluoric acid mainly comes from fluorite. At the same time, hydrogen fluoride is also the most primary product of fluorine chemical industry. It is mainly used in hydrofluorocarbon industry, accounting for about 50% of the total consumption of hydrogen fluoride. The second is electrolytic aluminum and aluminum processing industry Of aluminum fluoride and cryolite and other inorganic fluoride salt, accounting for more than 30%; again is other inorganic fluoride salt, petroleum alkane catalysis, metal pickling, military special products production industry. In recent years, China's increasing demand for anhydrous hydrogen fluoride, coupled with many foreign businessmen have come to China to purchase hydrogen fluoride and fluoride, etc., to promote the vigorous development of China's hydrogen fluoride production industry, the current annual production capacity of hydrogen fluoride to 1.5Mt or more.

The hydrothermal decomposition method of fluorinated silicic acid and sulfuric acid decomposition of fluorosilicic acid and sulfuric acid decomposition were introduced, including rotary kiln, gas-solid fluidized bed, gas-liquid-solid fluidized bed, batch method and artificial calcium fluoride method. The production of hydrofluoric acid in a variety of technology and the advantages and disadvantages of the process. The gas-solid fluidized bed process, the gas-liquid-solid fluidized bed process and the intermittent reaction process with the closed system of the whole system are considered to open up a new direction for the production of hydrogen fluoride by the reaction of fluorite and sulfuric acid, but the industrial application needs further study. The process of producing hydrogen fluoride from silicic acid has gained a new development in engineering and opened up a new source of raw material for hydrogen fluoride production, which has a good prospect.

The current rotary kiln production hydrofluoric acid technology, the general use of fluorite and sulfuric acid at room temperature or lower temperature by the external mixer screw or pre-reactor mixture into the rotary kiln reactor, because the reaction process does not want to bring too much inertia, the influence of the gas absorption of hydrogen fluoride condensation and rectification, the process heat is through the combustion gas, a large number of hot air (350 ~ 550 ℃) outside the jacket to heat the rotary kiln to provide heat to react, the hot gas system excess gas (around 320 ℃) outside row.