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Cryolite
Crurite, chemical formula cryolite na3alf6, also known as sodium hexafluoraluminate or sodium aluminum fluoride is a white fine crystal, odorless, density of 2.95~3.05g/cm³, specific gravity of 2.75~3.00g/cm³, hardness of 2~3, easy to absorb moisture. Cryolite is mainly used as a flux in the electrolytic aluminum industry, and can also dissolve alumina, melting into a liquid state at a high temperature of about 1000 degrees.