Model Experiment on Inclusion Removal by Bubble Flotation Accompanied by Particle Coagulation in Turbulent Flow

Abstract

Inclusion behavior like nucleation, diffusional growth, coagulation and removal in steel refining are complicated process, whereas mathematical simulation makes it possible to describe each behavior in detail. Many works have been performed in respect of the individual mechanism of inclusion behavior. However, the whole behavior is not clearly understood yet, and especially, an experimental evaluation of combined phenomena has not been carried out sufficiently until now. In this study, a cold model experiment of bubble flotation accompanied by coagulation of polystyrene particle in an electrolyte solution has been conducted in an agitated vessel under turbulent flow condition. In addition, an empirical equation of bubble flotation in a turbulent flow has been proposed from observed results of the water model experiment. This empirical equation has been combined with the population balance equation on particle coagulation, and removal rates have been predicted. Furthermore, a correction has been adopted in the population balance equation proposed by Nakaoka et al. Resultantly, a linear coupling model with bubble flotation and coagulation has been verified its applicability to a prediction of time dependence of particle number density and size distributions under various conditions.