Thermal analysis on two coals (semi-anthracite and high-volatile coking coal), iron ore, and their corresponding mixtures was performed using a computer-aided thermal analysis technique. Samples were heated to 1000°C at a typical rate of 10°C/min under an argon atmosphere. It was found that the iron ore undergoes several reactions prior to its reduction, which resulted in an endothermic heat effect. The iron ore reduction commenced at temperatures as low as 580°C and progressively increased at higher temperatures. Coal devolatilization was found to play an important role in iron ore reduction for the coal-ore mixtures at temperatures below 920°C, while the effect of char gasification resulting in CO as a reducing gas was dominant at higher temperatures. No apparent difference in the effect of coal devolatilization on reduction reactions was observed when low- and high-volatile matter coal was mixed with the iron ore. The main difference was detected only in the temperature range where char gasification became prominent and was predominantly responsible for the reduction of the iron ore. Similarities in the endothermic and exothermic peaks were found at different heating rates, indicating a unified reaction mechanism between them. However, the peaks shifted toward the higher temperature range under increased heating rates.
|Number of pages||6|
|Journal||Industrial and Engineering Chemistry Research|
|Publication status||Published - 2 Feb 2005|