Effect of addition of CaO component on the oxidation reaction of wüstite particles in sintering bed

Abstract

This study has been performed to understand the reaction behavior of wüstite particles and the effect of existing state of CaO component in the iron ore sintering bed for their effective utilization as an agglomeration agent. Changes in the structure and pressure drops of a sintering bed were measured by using a laboratory-scale sintering simulator. When wüstite particles were mixed with model pellet of raw materials, pressure drop of the sintering bed did not show significant change independent of average CaO content between 5 and 10 mass% CaO. This is because most of wüstite particles and model pellets kept their initial shapes and therefore the structural change of the sintering bed did not occur. On the contrary, pressure drop of the bed changed drastically when wüstite particles were mixed with CaO particles with 1.0-2.0 mm in particles size. In these cases, wüstite and CaO particles were melted and agglomerated each other. Addition of CaO component at the vicinity of the wüstite particles seems to decrease in liquidus temperature of local composition and promote the melt formation. In order to effectively utilize wüstite containing materials as an agglomeration agent, it is essential to arrange sufficient amount of CaO component close to such particles for melt formation at lower temperature.