关键词: 微波加热, 脱硫石膏, 磁铁矿, 分解渣, 烧结矿

Abstract: The microwave heating characteristic and decomposition of flue gas desulfurization (FGD) gypsum combined with anthracite and magnetite have been investigated with a microwave reactor. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and microcomputer rapid sulfur tester were used to characterize the decomposition residues. The FGD gypsum- (10%)magnetite- (8%)anthracite mixture showed the best microwave heating characteristics where the temperature rose up to 1000℃within 80min. After held for 60min, the desulfurization rate reached to 93.86%. The addition of magnetite, as a kind of catalyst and microwave absorber, significantly increased the sample's temperature and accelerated the decomposition of FGD gypsum to form Ca_xFe_yO_z and SO₂. With the increase of Ca_xFe_yO_z, the desulfurization rate further increased. The SEM images of the residues showed that the morphology of particle sintering took place during the decomposition of FGD gypsum in the presence of magnetite and anthracite under microwave heating. There were no remarkable difference in the chemical composition between Tai-gang sinter ore and the sinter with addition of 5% of the residues which acted as flux slag. Therefore, the decomposition residue can be used in sinter ore of shaft furnace.

Key words: microwave heating, FGD gypsum, magnetite, decomposition residue, sinter ore