Evaluation of Dust Generation during Mechanical Wear of Iron Ore Pellets

Abstract

Iron ore pellets undergo mechanical wear during handling, transportation and use in a blast furnace. This results in a loss of valuable raw materials and causes environmental problems in form of dust in off-gases from a blast furnace. Thus, this study is focused on the investigation of the mechanical wear of iron ore pellets and the dust formation. The characteristics of industrial pellets (such as size, weight, density and hardness) have been investigated. Moreover, the influence of pellet characteristics on the wear mechanism (sliding/abrasion and impact/collisions wear) and the characteristics of generated dust have been investigated. It was observed that the size of pellets can influence the wear rate under the given experimental conditions. The pellets with larger size (13.5<d_eq<15.0 mm) showed 10–20% higher wear rate as compared to small sized pellets (9.5<d_eq<12.50 mm). SEM studies of the dust generated during wear experiments inferred that larger contribution of impact/collisions in wear of pellets is the reason for the higher wear rate of large size pellets. Further, a relationship between the critical diameter of dust particles, which can be removed with off-gases from the blast furnace, and the velocity of off-gases in top part of blast furnace was developed.