Abstract:The dissolving rate of K2O from potassium feldspar and thesolid phase transformation were experimentally studied at 200～250℃ on hydrothe rmal-dissolving potassium feldspar, with CaO as the reactant and under the conditions of different Ca/(Al+Si) molar ratios, liquid/solid weight ratios, reaction temperatures and reaction periods. The experimental results indicate that the dissolving rate of K2O from potassium feldspar is 40%～80% and the solid product is well_crystallized fibrous tobermorite. Wet chemical analysis, XRD, SEM, DSC-TG and BET methods were used to characterize the synthesized tobermorite powers. The synthesized samples are hollow spherical agglomerates formed by fibroust obermorite crystals, which are 49～50 nm in thickness, 100～200 nm in width and 5～10 μm in length, suitable for making calcium silicate insulation materials.The heat insulating temperature of the synthesized tobermorite powder materials is as high as 650℃.
