Release and Transformation Characteristics of Modes of Occurrence of Chlorine in Coal Gangue during Combustion

To evaluate the release and transformation characteristics of different forms of Cl in coal gangue during combustion, the effect factors of combustion temperature, combustion time and air flux were investigated using a small tubular furnace; the modes of occurrence of Cl in coal gangue and its combustion residues under different temperatures were extracted with sequential chemical extraction; the changes of matrix composition before and after coal gangue combustion were characterized by XRD (X-ray diffraction), XRF (X-ray fluorescence spectrum) and FT-IR (Fourier transform infrared spectroscopy). The results indicated, during coal gangue combustion under 120 min of combustion time and 90 mL/min of air flux, the organic matter, kaolinite and ankerite were almost completely decomposed at 600 oC; the complete decompose for calcite and anorthite, for illite and pyrite were at 900oC and 1000 oC, respectively. Water soluble Cl in coal gangue decreased greatly in 400-600 oC, with a decrease ratio of 12.02%, acco...