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

More steel scrap consumption in iron and steel industry can not only alleviate the shortage of iron ore resources, but also greatly reduce production costs and carbon emissions to the air, which is a key link of low-carbon metallurgy. Due to the limitation of various factors, the consumption of steel scrap in present converter steelmaking process is limited, and the technology of multipoint adding scrap comes into being. The scrap melting behaviors in a 70 t refining ladle under different argon blowing rates with the steel scrap addition of different specific surface area and preheating temperature were numerically investigated and compared in this paper. The results showed that the melting rate of steel scrap increases with the increases of specific surface area, and the bottom argon blowing can obviously accelerate the melting of steel scrap, while the promoting effect gradually decreases as the increase of specific area. With bottom argon blowing, the core temperature of steel scrap with specific surface area of 120 m2/m3, 130.22 m2/m3 and 160.81 m2/m3 increased by 7.06 K/s, 6.51 K/s and 3.73 K/s, the melting rate was increased by 0.92 cm3/s, 0.88 cm3/s and 0.28 cm3/s, and the melting time was shortened by 17 s, 15 s and 3 s, respectively, compared with that without bottom blowing. When the initial temperature of steel scrap rises from 300 K to 1000 K, the melting rate increases from 2.97 cm2/s to 3.26 cm2/s, and the melting time is shortened by 3 s accordingly. The argon blowing rate significantly affects the melting rate of steel scrap. When the argon blowing rate increases from 100 L/min to 200 L/min, the melting time of steel scrap with specific surface area of 120 m2/m3, 130.22 m2/m3 and 160.81 m2/m3 is reduced from 44 s to 35 s, 42 s to 34 s and 34 s to 31 s, respectively. Therefore, on the premise of smooth production, the melting speed of steel scrap in ladle can be significantly accelerated by increasing the argon blowing rate and adding the slab scrap with higher initial temperature and specific surface area. The present study can provide certain theoretical guidance for the development of scrap rapid melting in ladle in steel plants.