Manufacturing Anhydrous Hydrogen Fluoride Products Utilizing Waste Acid Containing Fluorine.

Manufacturing anhydrous hydrogen fluoride products utilizing waste acid containing fluorine as a raw material.

Many fluorine chemical plants generate such waste acid, which typically contains hydrofluoric acid or a combination of hydrofluoric acid and fluorosilicic acid. These waste acid solutions are highly corrosive and are classified as hazardous waste. Traditionally, they are treated through acid-base neutralization, which transforms the fluorine into calcium fluoride sludge, making it "harmless." However, this method is costly and results in the production of sludge containing calcium fluoride, which wastes fluorine resources.

Our technology provides an alternative solution by converting waste acid containing fluorine into anhydrous hydrogen fluoride products. We can customize a complete production line to cater to the composition of the waste acid. This approach not only avoids costly neutralization but also utilizes fluorine resources, making it an efficient and eco-friendly option for waste management.

Our technological process is:

Depiction of Flow Chart:

The process of manufacturing anhydrous hydrogen fluoride involves mixing fluorine-containing waste acid with concentrated sulfuric acid, and decomposing fluosilicic acid into hydrofluoric acid and silicon tetrafluoride under appropriate temperature and pressure. HF and SiF4 are then volatilized in the form of steam.

The steam passes through a first-stage cooler, causing HF to condense into a liquid that is collected into a temporary storage tank. The steam then undergoes two rounds of condensation and refining, resulting in the production of anhydrous hydrogen fluoride (HF≥99.96%).

The treatment process described above transforms concentrated sulfuric acid into a mixture of dilute sulfuric acid and sulfate. To further utilize the dilute sulfuric acid, the sulfate is crystallized and separated from the liquid using solid-liquid separation. The dilute sulfuric acid is then concentrated until its concentration reaches ≥92%, and it is returned to the decomposition reactor kettle.

The condensed water vapor is condensed and becomes waste water, which is treated in a sewage treatment station.

(H2SO4≤1.0%, HF≤0.1% in wastewater)

With this technology, the recovery rate of fluorine resources is about 93 ~ 97%, and that of sulfuric acid is about 92 ~ 96%.