Reduction Behavior of Iron Ore Pellets with Simulated Coke Oven Gas and Natural Gas

摘要

Recently a special attention is being paid on the combination of different ironmaking technologies in the integrated steel plant to maximize the efficiency of the overall process. The utilization of coke oven gas for production of direct reduced iron (DRI) in the integrated steelmaking route is still under evaluation and discussion. In this study, iron ore pellets were isothermally reduced with simulated original and reformed coke oven gas (RCOG) at 700-980°C. The results were compared with those obtained by the reduction of pellets with the original and reformed natural gas (RNG). The highest reduction degree was obtained for the pellets reduced with RCOG while the lowest reduction degree was exhibited by original natural gas. On the other hand the rate of reduction with original coke oven gas was sharply increased at temperature of about 900°C to become higher than that of RNG. A slow down phenomenon appeared at the later stage of reduction due to the intensive carbon deposition. The soot formation increased as CH_4 content and/or the temperature of reducing gas increased. Reflected light microscope, scanning electron microscope with EDX, and high performance X-ray diffraction analysis were used to estimate the reduction kinetics and mechanism.