... of wells fireproofing material, building material2. size: 10-550um3. color: light gray or white 4. advantages: light weight, nontoxic, tasteless,corrosion resistant ... conductivity, excellent performance. Physical Analysis DataChemical Analysis Data AppearanceGrey/White powder Thermal diffusivity0.000903-0.0015m2/h SiO2 50-55 ... Refractoriness1550-1750c K2O 0.5-1.1% cenosphere coal ash white color