抄録
The authors have investigated the recycling technology of inorganic wastes to make high performance building materials and the stabilization technology of toxic heavy metals by using hydrothermal treatment. The starting materials were incinerated ash, concrete waste, and construction sludge. Ca(OH)2 was added to wastes so as to Ca(OH)2/wastes weight ratio of one ninth. The mixtures were formed and autoclaved at 180 degree C under saturated steam pressure for 6 h. Tobermorite (Ca5(Si6O18H2)4H2O) and hydrogarnet (Ca3Al2(SiO4)(OH)8) were formed by hydrothermal treatment. The flexural strength of the specimens varied from 3.2 to 16.2 MPa. The amount of dissolved heavy metal (Pb) was decreased to 1/40 after autoclaving, suggesting the possibility of the heavy metal fixation by hydrothermal treatment. To apply these solidified inorganic waste to paving tile, we determined that Ca(OH)2/wastes weight ratio is 15/85 for plant production. Field test has been carried out for one year.
