Asbestos-containing waste detoxification by a microwave heat treatment using silicon carbide as an inorganic heating element

Abstract

Asbestos-containing waste has been continuously generated due to the disposal of asbestos-containing products, and the development of asbestos detoxification and recycling technologies are required due to a lack of landfills. In this study, asbestos-containing waste was detoxified by a microwave heat treatment that used silicon carbide balls, which are inorganic heating elements that absorb microwaves and release heat at room temperature. For efficient heat treatment, the asbestos-containing waste was powdered by crushing and grinding processes and then a detoxification heat treatment was performed. The asbestos-containing waste powder particle size, heat treatment temperature, and heat treatment duration were adjusted to investigate the effect of the heat treatment conditions on the detoxification characteristics. After the heat treatment, the detoxification characteristics of asbestos-containing waste were analyzed using X-ray diffraction and scanning electron microscopy. Asbestos was completely removed from the crystal structure and microstructure when the microwave heat treatment was performed at 1200 °C for over 60 min and at 1300 °C for over 30 min. Using silicon carbide balls in the heat treatment enabled fast heat treatments because heating to the target temperature was possible within a short period of time.