Low Temperature Reduction Degradation Characteristics of Sinter, Pellet and Lump Ore

摘要

The reduction degradation characteristics of typical sinter, pellet and lump ore were tested with the reducing gas conditions simulating two kinds of irowmaking processes. The results show that, in the same condition of gas composition and temperature, the reduction degradation degree （RDI〈3.15mm） of sinter is high, RDI〈3.15mm of lump ore is low and RDI〈3.15 mm of pellet is in the middle level. With two kinds of gas composition simulating different iron-making processes, the reduction degradation indices （RDI） of three kinds of iron ores all present the tenden- cy of ＂inverted V-shape＂ in the temperature range from 450 to 650℃, and the RDI reach the maximum value at 550℃. The reduction degradation degrees of iron ores are extended when mixing the gas with hydrogen to increase the re duction potential, and the influence extent is discrepant for different iron ores. Colligating the increase amplitude of grains in small size fraction, the influence of reducing gas on lump ore is the greatest, the influence on sinter is the second, and the sensitivity of pellet on the reducing gas properties change is relatively small. As for the degradation form, lump ore and sinter both present the degradation ,of cracking, and the distribution of small grains generated from the cracking is in the range from 03 5 to 6. 3 mm uniformly. The lump ore presents surface cracking, while sin- ter presents integral cracking. The pellet presents the degradation of surface stripping, and the proportion of grains smaller than 0.5 mm is the highest, which is up to 90% in the grains smaller than 3.15 mm.