Abstract
This study discusses an autoclaved lightweight concrete (ALC) recycling system and the merits of this system. This recycling process includes carbonation reaction, sintering and autoclaving. In this recycling system, first ALC reacts with CO2 because the main contents of ALC are tobermorite (Ca5Si6O16(OH)2-4H2O) and α-quartz. Tobermorite can easily react with CO2 and then produce CaCO3 and silica gel. Sintering carbonated ALC between 650 to 800°C, belite (Ca2SiO4), one type of cement mineral, is produced. Then, autoclaving calcinated ALC at 750 to 800°C using an industrial process, tobermorite is reproduced. The merits of this recycling system include not only recycling ALC but also the reduction of carbon dioxide emissions. Using this recycling system, CO2 emissions from ALC production can be reduced about 350kg-CO2/ton according to calculations by a life cycle assessment (LCA) method.
