Reduction Efficiency of Iron Ore-Coal Composite Pellets in Tunnel Kiln For Sponge Iron Production

摘要

In order to explore the efficacy of iron ore-coal composite pellets over ordinary green pellets, indurated pellets, briquettes as well as standard charging of material in the form of concentric layers of iron ore and coal fines, or their mixture, these pellets were tested at 1,150 A degrees C in a 7 tons per day (7 tpd) pilot tunnel kiln. Reduction of iron ore coal composite pellets in tunnel kiln emerges with an edge over all other systems studied. Performance parameters like percentage metallic iron formed, percentage metallization, reduction efficiency, carbon utilization efficiency, energy efficiency have been calculated and found to be significantly higher for composite pellets than the other systems studied. The materials of the container are found to have significant effect on the reduction kinetics. Energy and carbon efficiency have also been observed to be higher for higher capacity kiln. Significant amount of energy (25 % of total loss) is found to escape through exit gas.