Hexafluorosilicic Acid - Uses

Uses

The majority of the hexafluorosilicic acid is converted to aluminium fluoride and cryolite. These materials are central to the conversion of aluminium ore into aluminium metal. The conversion to aluminium trifluoride is described as:

H₂SiF₆ + Al₂O₃ → 2 AlF₃ + SiO₂ + H₂O

Hexafluorosilicic acid is also converted to a variety of useful hexafluorosilicate salts. The potassium salt is used in the production of porceleins, the magnesium salt for hardened concretes and as an insecticide, and the barium salts for phosphors.

Hexafluorosilicic acid is also commonly used for water fluoridation in several countries including the United States, the United Kingdom, and the Republic of Ireland. In the U.S., about 40,000 tons of fluorosilic acid is recovered from phosphoric acid plants, and then used primarily in water fluoridation, sometimes after being processed into sodium silicofluoride.

Hexafluorosilicic acid is also used as an electrolyte in the Betts electrolytic process for refining lead.