Hydrothermal preparation of solidified materials form metakaolinite, quartz and slaked lime

Solidified materials were prepared by hydrothermal treatment of metakaolinite derived from the thermal dehydroxylation of kaolinite. Hydrothermal solidification was performed under saturated steam pressure at 180°C using powder-compacts consisting of metakaolinite, quartz and slaked lime. The hydrogarnet crystals formed newly after hydrothermal treatment. The bulk density and the bending strength of the hydrothermally solidified materials increased when the powder-compacts was prepared at a higher forming pressure. The mesopore volume and specific surface area of the hydrothermally solidified materials could be controlled by the forming pressure. It was clarified that the increase in the bulk density and the newly formation of fine-sized deposits seem to generate the strength of the hydrothermally solidified materials. And these caused the formation of mesopores.