Abstract: Through the KR hot metal pre-desulfurization water model test, the main factors affecting the KR hot metal desulfurization kinetics were analyzed and discussed. The research results show that the rotational speed of the agitator, the insertion depth of the agitator, the loading depth of the hot metal tank, and the tank diameter ratio have obvious effects on the kinetics of hot metal desulfurization. The particle dispersion was the best when the rotating speed was 140 r/min, the insertion depth of the agitator was 213 mm, the loading depth of the hot metal tank was 450 mm, and the tank diameter ratio was 0.42. It was found that the optimal range of vortex depth relative to agitator and vortex width relative to agitator was 0.96-1.17 and 0.66-0.72 respectively in the area with the best dispersion of desulfurizer particles.The optimal range of vortex depth relative to agitator depth and vortex width relative to agitator width was 0.88-1.37 and 0.61-1.20 respectively in the area with relatively well dispersion of desulfurizer particles. Based on the results of water model experiments, industrial experiments were carried out to optimize the KR kinetic conditions: compared with the original agitator's 66.8 %, the deep desulfurization ratio of hot metal in the optimized agitator increased by 7.2 percentage points to 74 %.The average mixing time of the new four blade agitator was 630 s, and the mixing cycle was shortened by 18 s. When the stirring period was shortened, the consumption of desulfurizer in the agitator after optimization was reduced by 1.2%, the temperature drop of molten iron decreased by 0.7 ℃,the secondary desulfurization rate reduced by 2.6 percentage points, and the iron loss of slag removal was reduced from 1.71 t to 1.39 t, a decrease of 18.7 %. Industrial tests show that the optimization of KR kinetic conditions has achieved good results under the condition of increasing the proportion of deep desulfurization.

Key words: KR desulfurization, water model, vortex shape, particle diffusion