it is crystalline white powder. Slightly soluble in water, density 2.95-3, melting point 1000oC, easily absorbing water and become damp, decomposed by strong acids like sulfuric acid and hydrochloride, then producing hydrofluoric acid and relevant aluminum salt and sodium salt. mainly used in flux of electrolytic aluminum, pesticide, flux of ceramic colors, anti-rubbing filling agent of resin and rubber, electrolytic liquid for production of iron alloy rimmed steel and furnish of emery wheel