Computational fluid dynamics study on gas-melt interaction in an industrial-scale top-submerged-lance furnace

• Systematic investigation into the effect of the furnace-to-lance diameter ratio (FLR) on gas-melt interactions in an industrial-scale TSL furnace • Increasing the FLR leads to increasing the axial and tangential jet velocities but reduces the bubble aspect ratio and gas-melt contact area • At FLR = 12, the bubble specific surface area is maximized while its volume remains moderate. This indicates optimal bubble dispersion and gas–liquid contact, thereby promoting bath stirring and reaction efficiency. • The high shear rate and high vorticity of the fluid, together with the entrainment of the melt phase by the bubbles primarily occur in the core region of the furnace • A larger FLR suppresses the melt splashing volume but has a limited effect on the splashing velocity • Increasing the lance diameter is favorable to suppress the formation of stirring dead zone • The findings provide theoretical guidance for optimizing the TSL process to improve efficiency and reduce environmental impact . Top Submerged Lance (TSL) technology holds significant potential for non-ferrous metal extraction, but requires deeper process understanding. This study employs a validated Volume of Fluid model to investigate hydrodynamics in the TSL lance and bath during blowing. The impact of the diameter ratio of TSL furnace to lance (FLR) on the jet properties (velocity components, strain rate and vorticity), bubble morphology (penetration depth, area, specific surface area, volume and aspect ratio), melt behavior (splashing volume and splashing velocity), and interaction between phases (stirring dead zone) are comprehensively investigated. The results indicate that increasing FLR leads to an increase in both axial and tangential velocity components. Increasing the diameter ratio enhances axial jet agitation intensity to the melt but reduces bubble area and aspect ratio. At FLR = 12, the bubble specific surface area is maximized while its volume remains moderate. This indicates optimal bubble dispersion and gas–liquid contact, thereby promoting bath stirring and reaction efficiency. The high fluid shear rate and vorticity, together with melt entrainment by bubbles occur primarily in the furnace core. Melt splashing volume decreases with increasing diameter ratio, whereas the effect of the diameter ratio on the splashing velocity is limited. Increasing the lance diameter helps suppress stirring dead zones. This study provides valuable insights into TSL technology and its potential for extracting non-ferrous metals, while the findings can contribute to optimizing the process by improving efficiency and reducing its environmental impact.