Per: larissa rodrigues de carvalho rocha (usiminas), Beatriz Fausta Gandra (USIMINAS), Gerson Evaristo de Paula Júnior (USIMINAS), Lucas Gonçalves Generoso (USIMINAS)
Abstract:
Reduction efficiency of iron ore in the blast furnace is controlled by the structure and permeability of the burden layers. The granular zone of the blast furnace is the region where the burden remains its stratified structure, due to charging, in the form of solid grains. In this region, the permeability conditions determine the gas distribution profile and, consequently, the thermal and chemical efficiency of the reactor. At Usiminas, was developed a permeability test that allows the evaluation of the pressure drop in beds formed by the raw materials used in the blast furnace, seeking the most favorable conditions for gas flow. Then it was possible to evaluate charges composed exclusively of sinter, pellet or granular ore, or binary combinations between them. The sinter presented the highest pressure drop, followed by pellet and granular ore. Despite this, the sinter was the material that allowed greater increase of gas flow. The tests indicated that 5% of material with a grain size smaller than 5 mm is the limit for the concentration of sinter fines, condition which there was an increase of approximately 50% in the resistance to the gas flow in velocities corresponding to those of blast furnace. The best permeability bed was composed of 95% sinter and 5% pellet, followed by 100% sinter, with no significant difference between these conditions. In general, the combination of sinter and pellet resulted better bed permeability.