Cenospheres is able to float on the surface of fly ash hollow ball, pale, thin wall hollow, very light weight, bulk density 720kg/m3(heavy), 418kg/ma (light), particle size of about 0.1mm, closed and smooth surface, thermal conductivity is small. Refractoriness 》1610℃ is the excellent insulation refractory cast able used in the production of light and oil drilling. The chemical composition of cenospheres of silicon dioxide and aluminum oxide-based, with fine particles, hollow, light weight, high strength ,wear resistance, high temperature, thermal insulation, fire-retardant insulation and other functions has been widely used one of refractory materials.