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

摘要： 研究了在微波炉中配加无烟煤磁铁矿的烟气脱硫石膏混合料的升温特性及还原分解性能,应用X射线衍射、扫描电镜和微机快速测硫仪对分解渣进行检测分析。微波加热下,配加10%磁铁矿和8%无烟煤(质量分数)的脱硫石膏混合粉的升温效果最佳,混合物料在80min内升温到1000℃,保温60min后,脱硫率为93.86%。作为催化剂和微波吸收剂,磁铁矿的加入提高了微波加热物料的温度,促进脱硫石膏分解生成Ca_xFe_yO_z,放出SO₂气体。随着Ca_xFe_yO_z含量的增加,物料的脱硫率提高。混合物料分解渣的SEM图像显示,微波加热下,配加磁铁矿和无烟煤的脱硫石膏混合物料分解的过程中发生粒子团聚烧结。配加5%分解渣的烧结矿化学成分与太钢烧结矿的化学成分无显著区别,此分解渣可以作为高炉烧结矿的熔剂配料来使用。

关键词: 微波加热, 脱硫石膏, 磁铁矿, 分解渣, 烧结矿