Melting mechanism of steel scrap in a converter with combined blowing

According to the context of "carbon peak and carbon neutralization", it is highly significant to investigate the melting mechanism and behavior of steel scrap in the converter to reduce the tap-to-tap time and enhance the usage of resource. In this paper, the melting behaviors of steel scrap in a full-scale converter under the conditions of without blowing, only top blowing, only bottom blowing and top-bottom combined blowing were numerically calculated by a three-dimensional turbulent-multiphase-melting-solute transport coupling model. Along with hot-state experiments, the mathematical model was verified. The results showed that the scrap melting in the converter is the result of the combined actions of heat transfer and mass transfer. When applying the top-bottom combined blowing, the melting time required for the scrap is about 485 s. Compared with bottom blowing, top blowing and without blowing, the melting time is shortened by about 45 s, 220 s and 290 s, respectively. The modes of top-bottom combined blowing and only bottom blowing can preferably promote the exchange of temperature and solute element carbon between the scrap and melt, leading to a stable temperature of 1700 K around the scrap, which is 10 K and 20 K higher than that of only top blowing and without blowing, respectively. Meanwhile, the end time of carburizing stage with top-bottom combined blowing is 200 s, which is about 100 s shorter than that of only top blowing and without blowing. The present study can provide theoretical guidance for deep understanding of scrap melting in converter, which is significant for improving the production efficiency.