Microstructures of Self-reducing Pellets Bearing Iron Ore and Carbon

Abstract

The steps Fe₂O₃→Fe₃O₄, Fe₃O₄→"FeO" and "FeO"→Fe, during the reduction of self reducing pellets plus charcoal (with volatile matter), between 1 223-1 423 K, were analysed. It was found that typical microstructures of the step Fe₂O₃→Fe₃O₄ consisted of transgranular cracks in the hematite particles and the Fe₃O₄ morphology was probably lamellar. The microstructures of the step Fe₃O₄→"FeO" were similar to and dependent on the first step of reduction and it was observed the formation of superficial microcracks in the "FeO" phase. The typical morphology in the step "FeO"→Fe was that of Fe whiskers between 1223-1323 K, but at 1423 K the found morphology was a mixed one, that is a dense morphology (clusters of cone shaped whiskers) adjacent to a porous morphology of iron.