... , nontoxic, tasteless,corrosion resistant, high temperature, pressure, insulation, small thermal conductivity, excellent performance. Physical Analysis DataChemical Analysis Data AppearanceGrey ... /White powder Thermal diffusivity0.000903-0.0015m2/h SiO2 50-55%Ture ... K2O 0.5-1.1%Itroduction hollow ceramic microspheres cenosphere for oil well