Research on Stirring Characteristics of Molten Bath with Swirl-Type Oxygen Lance for Large Scale Converter

In the modern steelmaking, the impact behaviour of supersonic oxygen jet on the molten bath is vital importance for the refining process. The impact characteristics and flow field distribution of molten bath for swirl-type oxygen lance in 260 Mg converter were analyzed by physical experiments and numerical simulations, and industrial test research was conducted. These results demonstrate that compared to the traditional oxygen lance, the cavity depth, cavity width and mixing time of swirl-type oxygen lance decrease, increase and decrease, respectively. The mixing efficiency of molten bath for swirl-type oxygen lance is improved by 5.5% to 16.8%. The optimal operation parameters of swirl-type oxygen lance for 260 Mg converter are H=40de and Q=80 Nm3·h-1. When the swirl angle is 10 °, the molten bath obtains the maximum volume-average velocity, the minimum dead zone volume and the shortest mixing time. Industrial test shown that compared with traditional oxygen lance, the swirl-type oxygen lance increased the dephosphorization rate by 2.3%, decreased the final carbon content by 0.005%, and decreased the iron content of final slag by 0.11%. The findings of this work can provide a basic reference for the industrial application of swirl-type oxygen lance in large-scale converter.