Rheological behavior and empirical model of simulated foaming slag

Abstract

The slags and fluxes found in modern steelmaking convertors all contain finely dispersed gas phases, which are generated by the refining reaction used to decarburize the molten iron. The frothing effect that is often generated as a result of these gasses can often prove to be a fatal obstacle in the efficient operation of the converter. In the present study, a simulated slag foam was produced by dispersing N2bubbles in silicone oil. The effect of varying the volume fraction and bubble size of the dispersed gas phase, the shear rate, and the viscosity of the liquid phase, was then systematically investigated by measuring the viscosity of the N2bubble dispersed silicone oil with a rotating viscometer. This found that the relative viscosity is increased as the volume fraction of the gas phase is increased, ultimately transitioning from a Newtonian to pseudo-plastic fluid at higher gas phase rates. In addition, an empirical model for the viscosity of the slag foam was developed by modifying the Einstein-Roscoe equation, with this model capable of reproducing the variation in relative viscosity with various gas phase rates, shear rates, and bubble sizes.