Heat Transfer Sensitivity Analysis for a Laboratory-Scale Brushed Arc Electrode Smelting Furnace

Steelmakers worldwide face increasing pressure to adopt sustainable low CO 2 emission production routes, with electric steelmaking emerging as a key pathway. Electric arc furnaces (EAF) require high-grade iron ore for direct reduced iron (DRI), whereas electric smelting furnaces (ESF) can tolerate wider variations in iron content and impurities. This makes the ESF suitable for utilizing Western Australia’s Pilbara ores, which are predominately used in blast furnace ironmaking. In the DRI–ESF route, iron ore can be reduced using hydrogen, then smelted in the ESF using electricity before refining in steelmaking processes. However, detailed mechanistic understanding of heat transfer, fluid flow, and chemical reactions in the ESF process for producing iron are currently lacking. This work investigates heat transfer behavior using a combination of simplified analytical approaches and computational fluid dynamic (CFD) simulations, validated using results of a laboratory electrode smelting furnace. First, this study focused on temperature-dependent thermophysical properties of metal and slag, incorporating flexibility for compositional effects. Dimensionless numbers were derived to assess the relative influence of driving forces on heat transfer and flow within the ESF. The scaling analysis revealed thermal diffusion as the dominant heat transfer mechanism, whereas natural convection, bubbling, and Marangoni effects are significant to the motion of the bath. Building on this, a CFD-based sensitivity analysis was carried out for two configurations covering the range of expected behavior: mixed slag–metal and slag-only models. This highlighted the roles of thermal conductivity, reduction reaction heat sink, and arc’s heat distribution temperature gradients in the process.