Briquettes Composed of LD Converter Steel Mill Wastes and Blast Furnace Dust to Produce Primary Iron and Liquid Steel Temperature Control

Several types of waste are generated in the integrated steel industry, in particular from wet or dry LD (Linz-Donawitz) converter dedusting systems and blast furnace cleaning equipment. These wastes contain iron, carbon and, in some cases, zinc, which have been the subject of several studies and technological initiatives in recent decades. In this work, the fine (F) and coarse (C) residues generated in a dry dedusting system of the LD converter were used in the proportion of 50-50% and 70-30%, respectively, and to these proportions were added dust residues from the blast furnace (BF) collector. Previously, the C and F residues were hydrated for 3 and 4 days, respectively, and the mixture was agglomerated with Portland cement ARI (Alta Resistência Inicial) and water to produce self-reducing briquettes, in order to study their behavior in compression, metallization and mainly as an alternative cooling agent in liquid steel to control its final temperature. The results were analyzed considering the energy balance of the briquette-steel bath system and taking into account a thermodynamic sequence for the main reactions and oxygen potentials typical of steelmaking processes. The self-reducing agglomerates proved to cause a high cooling effect in the steel bath compared to iron ore scrap and pellets. Moreover, considering their high metallization degrees, self-reducing briquettes are an effective way to recover the metal (iron) contained in the waste.