Manufacturing AHF Products By The Reaction of Fluorite Powder & Sulfuric Acid.
Anhydrous Hydrogen Fluoride (AHF) is a fundamental material in the modern fluorine chemical industry, serving as a building block for the production of elemental fluorine, various fluorine refrigerants, new fluorine-containing materials, inorganic fluoride salts, and various organic fluorides.
We offer production line technology and equipment for 10kt/a, 20kt/a, 30kt/a, and 50kt/a.
The production of anhydrous hydrogen fluoride involves the use of fluorite powder and sulfuric acid as primary raw materials.
Flow Chart:
The wet calcium fluoride is dried in a rotary drying furnace (this step can be skipped if dry calcium fluoride is purchased), then conveyed to the fluorite powder storage bin and metered before entering the pre-reactor.
Sulfuric acid from the nicotinic acid reactor is also metered and enters the pre-reactor, where some chemical reactions occur, producing HF gas.
Any unreacted CaF2 and H2SO4 mixture enters the indirectly heated rotary kiln for complete reaction.
The pre-reactor has a reaction gas outlet connected to the pre-washing tower.
The reaction gas from both the rotary kiln and pre-reactor are washed in the pre-washing tower and washing tower with sulfuric acid to remove dust and moisture, sulfur, and separate impurities such as H2SO4 and HSO3F.
The sulfuric acid from the washing tower returns to the nicotinic acid reactor.
After cooling and condensing, the hydrogen fluoride gas enters a cooler and a condenser, where it is liquefied into crude hydrogen fluoride liquid.
The crude hydrogen fluoride liquid then enters a rectifying tower and degassing tower, where SO2, SiF4, H2SO4, H2O, and inert gas are removed.
After purification, the refined hydrogen fluoride liquid is obtained, which is then transferred to a storage tank for sale as a product after passing quality tests.
The non-condensable gas containing residual HF from the condenser and refining tower is absorbed by H2SO4 in the sulfuric acid scrubber, and is then recycled in the scrubbing tower and pre-scrubbing tower.
The SiF4 gas absorbed by water in the fluorogypsum treatment system is sent to the fluosilicic acid absorption system, where it is absorbed by the dilute fluosilicic acid to produce H2SiF6 solution with a concentration of more than 35%.
This fluosilicic acid solution can be sold directly or used as a raw material for producing various fluorine-containing products such as cryolite, ammonium hydrogen fluoride, potassium fluoride, and potassium fluosilicate.
It can also be further processed to produce anhydrous hydrogen fluoride and SiO2 using specialized technology.
The remaining tail gas is treated by absorption with an alkaline solution to ensure it meets emission standards before being discharged. Calcium sulfate (CaSO4) produced as a by-product of the reaction furnace is discharged from the tail of the rotary kiln.
It is neutralized with lime, cooled, and treated for tail gas absorption before being stored in a fluorgypsum slag bin for transportation.
Fluorgypsum is typically used in construction and cement manufacturing.
The hydrogen fluoride gas and slag gas entrained in the fluorgypsum are absorbed by water and then sent to the fluorosilicic acid absorption system for washing and SiF4 absorption.