Manufacturing carbon storage sintered body using microwave-selective and high-speed heating techniques

Microwave sintering of fly ash samples with large amounts of unburned carbon and CaCO₃ was examined in this study. To this end, CaCO₃ was mixed with fly ash sintered body to fix CO₂. The decomposition of CaCO₃ was observed when the raw material was heated to 1000 °C using microwave irradiation; however, a sintered body containing aragonite was obtained when the raw material was heated to 1000 °C with added water. Further, carbides in the fly ash could be selectively heated by controlling the microwave irradiation. The microwave magnetic field created a temperature gradient of 100 °C in a narrow region of 2.7 μm or less in the sintered body, and it helped suppress the CaCO₃ decomposition in the mixture during sintering. By storing water in the gas phase before spreading, CaCO₃, which is difficult to sinter using conventional heating, can be sintered without decomposing.