Fluorosilicic acid - ammonium fluoride - ammonium bisulfate production of hydrofluoric acid: Silica fluorosilicic acid with ammonia stripped become a solution of ammonium fluoride, ammonium fluoride solution after concentration, crystallization, separation to obtain a solid ammonium fluoride; ammonium fluoride and ammonium bisulfate reaction of hydrofluoric acid and ammonium sulfate; decomposition of ammonia and ammonium sulfate, ammonium hydrogen sulfate, ammonia Back fluosilicic off silicon, hydrogen fluoride, ammonium hydrogen sulfate back to the reaction system.

Major equipment: ammoniated desilication reactor, filter, multi-effect evaporator, efficient deaminase recovery tower, air dryer, hydrogen fluoride reactor, condenser, hydrogen fluoride rectification column, ammonium sulfate decomposition and so on.

The process features: by ammonia and ammonium bisulfate, the fluorosilicic acid is decomposed into hydrogen fluoride and silica. The process is short, wide application, ammonia and ammonium bisulfate only as an intermediate medium, in theory, do not consume, in fact, consumption is very low; the production process does not produce other byproducts, and no environmental pollution substances, in line with national development circular economy; moreover, the process equipment investment, annual output of 20,000 tons of hydrogen fluoride apparatus, equipment investment is less than 60 million yuan, covers an area of only about 20 acres. Therefore, the process has promote prospects.