Settling of Particle in Foaming Slag

Abstract

In the steelmaking process, molten slag is foamed through gas injection and gas generation reactions, and molten iron droplets get mixed and trapped in the slag. A settling velocity of an iron droplet in the foaming slag are very important, because a residence time of an iron droplet in the slag is directly calculated the settling velocity. According to the previous research, the settling velocity is expected to be slower than in regular non-foaming slag. However, it has yet to be quantitatively clarified. This study measured the settling velocities of particles through a foaming liquid of glycerin-water solution. A dimensionless correlation equation for particle settling velocity in the formed liquid was proposed by conducting a dimensional analysis of the experimental data. Using the obtained equation, we have predicted the settling velocity of iron particles in the foaming slag. It was clarified that the settling velocity of iron particles is highly affected by a volume fraction of gas phase in the foaming slag. There is a certain threshold for the velocity, and the velocity abruptly became zero when it falls below that threshold.