Hydrothermal synthesis of aluminum substituted tobermorite by using various crystal phases of alumina

Slurries of quartz and slaked lime containing various crystal phases of alumina were hydrothermally reacted to synthesize aluminum-substituted tobermorite. X-ray diffraction results confirmed the formation of aluminum-substituted tobermorite during the reaction. The aluminum species were substituted at the Q² or Q³ sites in tobermorite. The amount of aluminum substituted in the tobermorite depended on the reactivity of alumina. The tobermorite formed showed fiber- and plate-like morphologies. The reactivity of the alumina used as an additive influenced the substitution site and the amount of aluminum substituted into the tobermorite structure, resulting in controlling its morphology.