Reduction of Iron Ore-Coal Pellet in Air

During the reduction of iron ore?coal pellet in air,the combustible gas generated from the reduction in pellet is burnt onto the firing surface around the pellet.Between the pellet surface and the firing surface,there is such mixing gas containing the combudstible gas and burnt gas.It may be sure that the iron ore?coal pellet is no oxidized in the week oxidizing atmosphere.The heat released by combusition on the firing surface is fast tranfered into the pellet,and the self?heating reduction of iron ore?coal pellet may occur.