Abstract: To improve the desulfurization efficiency of hot metal predesulfurization process with injection method, a CFD-DSM(Computational Fluid Dynamics-Desulfurization Model) coupled model was established based on 180 t hot metal ladle. The gas-solid-liquid multiphase flow behavior and reaction kinetics during hot metal pre-desulfurization process were systematically studied, and the contribution of dissolved magnesium desulfurization, magnesium bubble desulfurization, calcium oxide desulfurization, and slag layer desulfurization to the desulfurization reaction was revealed. The effects of carrier gas and magnesium powder flow rates on the desulfurization reaction were clarified. The results are shown as follows: the bubbly plume has a smaller penetration depth, but it does not float up attached to the wall of lance. With the continuous injection of calcium oxide powder, powder floats along the wall of lance. In the desulfurization process, the desulfurization by dissolved magnesium is the main desulfurization mechanism, followed by magnesium bubble desulfurization, calcium oxide desulfurization and slag layer desulfurization, and the desulfurization rate of each reaction mechanism first increases and then decreases. The carrier gas flow rate has little effect on desulfurization reaction. However, the magnesium powder flow rate has the greatest impact on the desulfurization reaction. For the hot metal with an initial sulfur mass fraction of 470×10^-6, when the sulfur mass fraction reaches 100×10^-6, the injection time is shortened by about 43 s for every 1 kg/min increase in magnesium powder flow rate.

Key words: hot metal ladle, submerged injection, multiphase flow behavior, reaction kinetics