Numerical Study on Gas-Metal-Slag Interaction with Single-Flow Postcombustion Oxygen Lance in the Steelmaking Process of a Top-Blown Converter

Gas-metal-slag interaction with traditional oxygen lance and single-flow postcombustion (PC) lance is compared by fluid volume method (VOF). Then, the industrial trials are carried out in a 120-ton top-blown converter to evaluate their metallurgical effects. Simulation results indicate that oxygen jet is injected to the liquid bath, generating a cavity. The liquid bath appears to have an unstable flow condition. Compared with the traditional lance, the PC lance is more helpful for stirring and mixing of liquid bath. The cavity diameter and depth with the PC lance are increased by 5.8% and 4.3%, respectively. Additionally, an improved model is proposed, which considers the momentum superposition of secondary flow and modifies the value of K characterizing the velocity attenuation. Industrial tests show that many metallurgical properties have been optimized by the PC lance, for example, the blowing time shortens by 93 s, the dephosphorization rate increases by 1.67%, and the scrap ratio increases by 1.3%.

Automated summary

By comparing the gas-metal-slag interaction between traditional oxygen lance and single-flow postcombustion (PC) lance, it was found that the PC lance is more effective in stirring and mixing the liquid bath. Industrial trials also confirmed the optimization of metallurgical properties achieved by the PC lance.