Laser-induced reduction of iron ore: Trends of the chemical distribution across the domains

Abstract

The reduction of iron ore powder in a laser-induced thermal cycle using several reducing agents was studied. The laser-assisted reduction process resulted in the formation of iron-rich domains, irregularly embedded in a slag matrix, and transitional phases. The appearance of these various chemical phases was categorized and geometrically evaluated with respect to representative dimensions using scanning electron microscopy. The statistical trends of the morphology are presented, in context with trends of the chemical composition across the domains, to gain a better understanding of the mechanisms behind the reduction process. Iron domains were predominately observed in the vicinity of the Si-rich zones, indicating the occurrence of the reduction reaction as a result of the Fe2O3-Si interaction. Furthermore, different appearances of the Fe-rich domains and other phases in the close proximity to iron were analyzed and discussed based on diffusion and coalescence phenomena. The obtained results show that the reduction occurs, but the process is still uncontrolled and only partially understood. Further analysis and experiments are, therefore, needed to investigate the prospects of the proposed method.