The main component of bauxite is alumina, which is
hydrated alumina containing impurities and is an earthy mineral.
White or
off-white, brownish yellow or light red due to iron. Density 3.9 ~
4g/cm3, hardness 1 ~ 3, opaque, brittle. Extremely difficult to
melt. Insoluble in water, soluble in sulfuric acid and sodium
hydroxide solution.It is mainly used for high aluminum
refractory
materials and can also be used to make fused brown
corundum.