Gas‐stirred ladles are widely used in the steel secondary refining process. In order to produce high‐quality steel, a range of stirring conditions, from hard stirring for mixing to gentle stirring for inclusion removal, is required. In this paper, a full scale unsteady three‐dimensional computational fluid dynamics (CFD) model is developed to simulate the bubble behavior in a steel ladle. A volume of fluid (VOF)‐Lagrangian approach is applied to simulate multiphase flow characteristics. The VOF method is used to track the liquid steel and slag, while the Lagrangian method is used to track the movement of argon bubbles. A water model is used to validate the gas‐stirred ladle model against experimental data. Flow field and bubble breakup and coalescence phenomena inside the ladle is studied in the baseline case, and the effects of initial bubble diameter and gas flow rate during the stirring process have been investigated through parametric study as well.

In a steel-refining ladle, the properties of manufactured steel can be notably degraded due to the presence of excessive inclusions. Stirring via gas injection through a porous plug is often used as part of the steel-refining process to reduce these inclusions. In this paper, 3D computational fluid dynamics (CFD) modeling is used to analyze transient multiphase flow and inclusion removal in a gas-stirred ladle. The effects of gas stirring with bubble-inclusion interaction are analyzed using the Euler–Euler approach for multiphase flow modeling, while the effects of inclusions aggregation and removal are modeled via a population balance model (PBM).

Low sulfur content is crucial in secondary steelmaking to enhance steel quality. The desulfurization rate is influenced by slag-steel interactions, including slag eye size and interfacial mass transfer coefficient. Gas-stirred ladles can impact the interaction through stirring conditions such as argon flow rate and dual plug separation angle. Using a 3D CFD simulation model, the effects of different stirring conditions on the desulfurization rates, molten steel flow, and slag-steel interfacial behaviors were investigated. Results showed that 180°separation angle leads to higher desulfurization efficiency than 90°. A higher argon gas flow rate increases desulfurization rate, and using 20 SCFM (8.92×10 -3 Nm 3 /s) argon flow rate for both plugs resulted in higher desulfurization rate than using 5 SCFM (2.23×10 -3 Nm 3 /s) for one plug and 20 SCFM for the other. The smallest desulfurization efficiency was observed when using 5 SCFM for both plugs.