Effects of ash/K2CO3/Fe2O3 on ignition temperature and combustion rate of demineralized anthracite

The effects of ash/K2CO3/Fe2O3 and their interactions on the ignition temperature and combustion rate of acid-washed anthracite were examined. The coal ashes from combustion of anthracite at different temperatures showed very different properties such as chemical compositions, color and morphology. Reactivities of demineralized anthracite with and without catalysts were measured by thermo-gravimetric analyzer (TG-DTG). The results indicate that ash itself has no catalytic effects on ignition temperature while the combustion rate is improved, especially by the ash prepared at high temperatures. The use of ash with K2CO3 (or Fe2O3) together as combustion catalysts reveals that the interactions (i.e. sintering reactions) between them have caused the reduction in combustion rate, compared with the cases when K2CO3 or Fe2O3 was employed individually. Similarly, the synergistic effect between K2CO3 and Fe2O3 was also observed to lower the combustion rate of demineralized anthracite.