A novel approach for the resource utilization of zinc-bearing dust and sludge via the blast furnace main trough

Abstract

Minimizing the environmental impact of zinc-bearing dust and sludge (ZDS) while efficiently extracting valuable metals from its intricate mix has become a pressing issue for steel mills. To facilitate comprehensive ZDS usage, we propose a novel approach for recycling ZDS in the blast furnace main trough. This work explores the self-reduction reaction principles of carbon-containing pellets derived from ZDS. Moreover, it examines the consequent alterations in the physical and chemical properties of molten iron and slag. The molten iron temperature inversely correlates with the number of added pellets; the temperature declines as more pellets are introduced. To restrict the molten iron's temperature decrease to within 30℃, it is advisable to limit the quantity of pellets added to 20 kg per ton of molten iron. At 1500℃, the self-reduction reaction of the pellet initiates 1.5 min post its introduction into the molten iron and concludes 12 min thereafter. The pellet mass percentage entering the molten iron is 32 %, whereas the mass percentage of iron elements within the pellet entering molten iron is 64 %. The pellet addition results in an uptick in blast furnace slag viscosity, yet it remains within an acceptable viscosity range (<1Pa·s).

Keywords: Blast furnace main trough; Carbon containing pellets; Resourceful treatment; Self-reducing reaction; Zinc bearing dust and sludge.