Behavior of Gas-Slag-Metal Emulsion with Nozzle-Twisted Lance in Converter Steelmaking Process

Oxygen lance is the key to realize the emulsification of gas-slag-metal in the converter steelmaking process, which determines successful completion of metallurgical tasks. Herein, a 3D full-size gas-slag-metal coupling model of the nozzle-twisted lance in a 120t converter is established. The behavioral characteristics of gas-slag-metal of nozzle-twisted lances (swirl angle 0 degrees/5 degrees/10 degrees/15 degrees) are studied. With the increase in the swirl angle, the axial velocity is reduced; the radial and tangential velocities are increased, and the coverage area of the slag layer, the splashing amount, and its height are reduced. In the longitudinal section, when the swirl angle increases from 0 degrees to 15 degrees, the areas of high-velocity and dead zones are reduced by 15% and 36%, respectively, and the area of low-velocity zone is increased by 17%. At different depths of molten bath, with the increase in the swirl angle, the area of high-velocity zone first increases and then decreases; the area of low-velocity zone increases, and the area of dead zone decreases. Finally, the industrial experiment with the nozzle-twisted lance is carried out in a 120t converter. The phosphorus content, the carbon-oxygen product, and the total iron content in slag are all reduced.