Numerical simulation on the melting behaviors of steel scrap in a ladle with bottom argon blowing

More steel scrap consumption in the iron and steel industry can not only mitigate the shortage of iron ore resources but also greatly lower production costs and carbon emissions to the atmosphere, which is a crucial link in low-carbon metallurgy. Because of the drawbacks of different factors, the amount of steel scrap consumed in the current converter steelmaking process is restricted, and the technology of multipoint adding scrap comes into play. Thus, steel scrap addition into ladles has gradually garnered attention from metallurgical experts, but there are few reports on the three-dimensional melting behavior of steel scrap in a real ladle environment with argon blowing. To examine the melting law of steel scrap in a ladle, in this study, the flow field, temperature distribution, and melting behavior of steel scrap in a 70 t refining ladle at various argon blowing rates with steel scrap addition of different specific surface areas and preheating temperatures were numerically investigated and compared using a mutiphysical mathematical model. The results revealed that the melting rate of steel scrap increases with increasing specific surface area, and bottom argon blowing can accelerate the melting of steel scrap, while the promoting effect gradually decreases with increasing specific area. With bottom argon blowing, the core temperature of steel scrap with specific surface areas of 120, 130.22, and 160.81 m²·m^–3 increased by 7.06, 6.51, and 3.73 K·s^–1, the melting rate was increased by 0.92, 0.88, and 0.28 cm³·s^–1, and the melting time was shortened by 17, 15, and 3 s, respectively, compared with those without bottom blowing. When the initial temperature of steel scrap increases from 300 to 1000 K, the melting rate increases from 2.97 to 3.26 cm²·s^–1 and the melting time is shortened by 3 s accordingly. The argon blowing rate significantly influenced the melting rate of steel scrap. When the argon blowing rate increases from 100 to 200 L·min^–1, the melting time of steel scrap with specific surface areas of 120, 130.22, and 160.81 m²·m^–3 is reduced from 44 to 35 s, 42 to 34 s, and 34 s to 31 s, respectively. Thus, on the premise of smooth production, the melting speed of the steel scrap in the ladle can be significantly increased by increasing the argon blowing rate and adding the slab scrap at higher initial temperatures and specific surface areas. This work offers a reference for developing steel scrap rapid-melting technology for ladles in steel plants.