Usage: used in rocket and missile, petroleum chemicals, metallurgy, electronics, space technology, atomic energy industry, light industry, agriculture, animal raising and environmental protection. Specification: SiO2: 67.59% TiO: 0.07% Al2O3: 12.06% MgO: 0.22% Fe2O3: 0.95% Hardness: 4.5~5 Density: 2~2.2g/cm3 Loss of Ignition: 9.5~11.8% Output: 1000t/m.