Transformation behavior of excluded pyrite during O2/CO2 combustion of pulverized coal

The present paper was addressed to the transformation of excluded pyrite during O-2/CO2 combustion of pulverized coal. Raw pyrite mineral was added to a pulverized coal sample, which was density-fractionated to remove the excluded minerals, to simulate the excluded pyrite present in coal. The mixed sample was burned in a drop tube furnace in O-2/CO2 and O-2/N-2 conditions to generate the residue ash, which was characterized by Mossbauer spectroscopic and size analyses. It was found that, in comparison with O-2/N-2 combustion at a same oxygen concentration, less iron glass silicate formed from excluded pyrite and silicates although the transformation of pyrite to oxides in O-2/CO2 combustion, different from the behaviors of included pyrite observed in previous study. Additionally, less fragmentation of exclude pyrite particles was observed in O-2/CO2 combustion.