Cryolite

Cryolite (CAS 13775-53-6, EC 237-410-6) is an inorganic sodium aluminium fluoride salt, commercially known under trade names including Cryocide, Kryolith, and Cryodust, with the shorthand formula Na3AlF6. It occurs naturally as a mineral but is predominantly supplied today as a synthetic amorphous powder. No E-code designation applies to this substance.

In aluminium smelting, cryolite functions as a flux and electrolyte solvent, lowering the melting point of alumina to enable energy-efficient electrolytic reduction. In agriculture, it acts as a contact insecticide and stomach poison against chewing insects by disrupting their digestive enzyme activity. It also serves as a pH buffer and fluoride source in specialised water treatment and catalytic processes.

Cryolite is sourced in technical and agricultural grades, supplied as powder or granules. It falls under REACH registration requirements within the EU. Procurement teams should confirm purity specifications and fluoride content against application requirements, as these vary between metallurgical and agrochemical grades.