An investigation of the relationship between compressive strength and dust generation potential of magnetite pellets

Iron ore pellets should have sufficient mechanical strengths against degradation at all stages of pellet production in pelletizing plants. Besides the strength, pellets should have less dust emission during operation since the process efficiency and the pelletizing equipments are adversely affected by dust. Dust is also a problem for sintered (product) pellets since they abrade during transportation from pellet production site to the reduction facilities. Sufficient mechanical strength and low dust emission of pellets are necessary for better operation and handling of pellets. In this study, dust emission mechanism of sintered magnetite pellets produced with different binders was comparatively studied. The results showed that the dust is not produced by pellet breakdown for sintered pellets with sufficient strength. It was found that dust generation of sintered pellets is not directly dependent on the mechanical strength. One of the dust generation mechanisms of sintered pellets with sufficient strength is the roughness of pellet surfaces. The attrition and impact forces during transportation cause dust generation from pellet surfaces. The surface smoothness is more important since the pellets with high strength and rough surfaces produced more dust than those with smooth surfaces and low strength. Half of the fines generated due to pellet attrition or impact forces during handling of sintered pellets will become airborne and are considered as loss and operational/environmental problem. The percentage of particulate matter (PM10) which is significant in health risk lied between 30% and 40% by weight of airborne pellet dust.