Reduction Behavior of Sinter Based on Top Gas Recycling-Oxygen Blast Furnace

Abstract

In order to explore the behavior laws of sinter reduction in TGR-OBF (top gas recycling-oxygen blast furnace), reduction experiments of sinter have been conducted by thermal balance mass loss method with different atmospheres, temperatures and volume flows. The changes of RI (reduction degree of Fe2O3), RI' (reduction rate of Fe2O3) and r (reduction degree of FeO) have been examined. The results show that the reduction of sinter was significantly improved under TGR-OBF atmosphere, and the RI and r were measured up to 98.2% and 97.8% at 900°C respectively. With increasing of the reduction temperature, the reduction of sinter speeded up greatly, and the reduction time-duration shortened from 117 min at 900°C to 63 min at 1100°C. Moreover, the reduction of sinter enhanced with increasing of the reductive gas flow. When the flow increased from 10 to 15 L/min, the initial reduction rate of sinter increased from 2.47%/min to 3.73%/min. While increasing H2 and CO contents in the reductive atmosphere, the reduction of sinter was promoted. Besides, H2 influenced more evidently than CO to the reduction of sinter, especially in the later stage of the reduction process, for instance, the reduction of wustite will be improved enormously when increasing the H2 content in the reductive atmosphere.