Abstract
Microwave sintering of fly ash samples with large amounts of unburned carbon and CaCO(3) was examined in this study. To this end, CaCO(3) was mixed with fly ash sintered body to fix CO(2). The decomposition of CaCO(3) 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 CaCO(3) decomposition in the mixture during sintering. By storing water in the gas phase before spreading, CaCO(3), which is difficult to sinter using conventional heating, can be sintered without decomposing.