Impact of New Iron Feeds on BOFs: Mass and Energy Balance

The global shift toward decarbonised steel production has driven interest in incorporating an electric smelting furnace (ESF) to process low-grade direct reduced iron (DRI). The ESF produces hot metal for the basic oxygen furnace (BOF), serving as a potential replacement for blast furnace (BF) ironmaking. In addition, the scarcity of high-quality scrap has increased interest in DRI as a coolant in the BOF. However, the thermochemical implications of using ESF hot metal and DRI with varying conditions in the BOF remain underexplored. Building on a study by Madhavan et al. [ 1 , 2 ], this study evaluates the influence of alternative feed on BOF performance using a validated mass and energy balance (MEB) model. Simulations cover 2.5–3.5 wt% C and 0–1 wt% Si in ESF hot metal for pig iron replacement, and three DRI types with varying gangue and carbon content for scrap substitution in a 330-t BOF. Results show that reduced carbon and silicon significantly decrease the available chemical heat. Within the studied range, the processable scrap ratio drops below 15% in most cases. Each 10 °C increase in hot metal temperature increases the scrap ratio by 0.38–0.50%. Contour plots are developed as a preliminary operational guide, illustrating slag generation and end-point phosphorus level as a function of ESF hot metal composition. For DRI, results indicate an effective cooling effect on the bath governed by metallization and gangue content. Overall, the results highlight the importance of optimizing ESF hot metal conditions and DRI characteristics to maintain heat balance and stable BOF operation.