抄録
Hydro-thermal synthesis on the aluminium ion containing tobermorite was studied using pyrophyllite as a source of Al2O3. Reactivity of pyrophyllite in the system CaO-Al2O3-SiO2-H2O and the influence of Al2O3 on the crystal structure of the product were investigated through the preparation of hydrous calcium silicate crystals containing various amount of Al2O3. In general, pyrophyllite had been considered stable chemically, but it was proved that pyrophyllite had a special reactivity in the hyhdro-thermal treatments, that is, according to our results, more than 54% of Al2O3 in pyrophyllite was participated in the reaction for 8 hrs treatment and more than 63% of Al2O3 was similarly for 24 hrs treatment at 175°C.
Tobermorite contained Al2O3 higher than 3% shown the structural disorder, and the lattice constant of tobermorite crystals which were prepared by the experiment, was changed by addition of pyrophyllite up to 7%, as Al2O3 for the system CaO-Al2O3-SiO2-H2O.
Consequently, Al-containing tobermorite is distinguished from Al-free tobermorite by the X-ray diffraction analysis, D. T. A. and the electron diffraction patterns. These without Al-containing tobermorite and hydrogarnet were produced by addition of pyrophyllite more than 7-9% as Al2O3.
