IMPACT OF OXYGEN INJECTION PARAMETERS ON REFINING IN INDUSTRY-SCALE EAF USING CFD

The Electric Arc Furnace (EAF) process consists of several key stages: charging, where raw materials like scrap metal are loaded; melting, where high-power electric arcs generate intense heat to liquefy the charge; refining, which involves removing impurities and adjusting the chemical composition through oxygen injection and slag formation; and tapping, where the refined molten steel is tapped for further processing. The current study focuses on the refining stage of the EAF, where carbon is removed through decarburization—a series of exothermic oxidation reactions facilitated by supersonic oxygen injection. A key aspect of this study is the formation of iron oxides (FeO) during refining, as FeO significantly influences slag chemistry, steel yield, and process efficiency. The study examines the relationship between FeO generation, carbon reduction, and oxygen injection parameters, aiming to identify optimal conditions for efficient decarburization while minimizing oxidation losses. To achieve this, a CFD-based refining simulator is employed, using a decoupled modeling approach that simulates the coherent jet domain and liquid steel bath separately. Jet parameters are calculated using isentropic flow equations, maintaining Mach numbers between 2.0 and 2.4. The model was validated against industrial trial data from the EVRAZ NA furnace, where, for an initial carbon content of 0.065%, the predicted decarburization trend showed an 8.57% deviation from observed values, confirming the model's reliability. Further investigations revealed that a 10% increase in oxygen flow led to a 5% improvement in carbon removal but resulted in a 22% increase in FeO generation, while a 15% decrease in oxygen resulted in 43% higher carbon levels and 23% less FeO. Additionally, comparing 3 and 6 co-jet burner configurations showed that increasing the number of burners—while reducing individual flow rates—achieved 32% faster decarburization with only a 28.5% increase in FeO. These findings demonstrate that optimizing both oxygen injection rate and burner configuration can significantly improve refining performance, reduce material losses, and enhance process efficiency in industrial-scale EAF steelmaking.