Ammonium fluorosilicate is an inorganic compound with the chemical formula (NH₄)₂SiF₆ that usually exists in the form of colorless to white crystals or powders. It is a salt that is soluble in water, but it weathers in dry air, forming a mixture of ammonium fluoride and silicic acid.

The following are some of the main uses of ammonium fluorosilicate:

1. Ceramics and glass industry: Ammonium fluorosilicate is used as a flux for ceramics and glass, it can reduce the melting temperature and speed up the melting rate, thereby reducing energy consumption and helping to improve the texture and transparency of the final product.

2. Aluminium smelting industry: In the smelting process of aluminum, ammonium fluorosilicate is used as a flux to help remove impurities in aluminium ore and improve the purity of aluminum.

3. Disinfectants and cleaners: Ammonium fluorosilicate has a certain disinfecting and cleaning effect, so it may be used as a disinfectant or detergent ingredient, especially if disinfection and cleaning need to be done at the same time.

4. Wood preservative: It can be used for wood preservative treatment, prevent wood rot and insect damage, and prolong the service life of wood.

5. Agriculture: Ammonium fluorosilicate is sometimes used as a soil disinfectant and insecticide, but due to its potential toxicity, this use is highly regulated and has been replaced by safer alternatives in many regions.

6. Metal surface treatment: In metal processing, ammonium fluorosilicate may be used for cleaning and pre-treatment of metal surfaces to remove oxides and other impurities.

7. Fluorinating agent: In chemical synthesis, ammonium fluorosilicate can be used as a fluorinating agent for the introduction of fluorine atoms into organic molecules.