Modeling of slag eye formation over a metal bath due to gas bubbling

Abstract

When gas is bubbled through a molten metal, overlying slag is pushed to the side forming an open ''eye'' of exposed metal. Eye sizes were measured in room-temperature modeling over a wide range of conditions including the fluids to simulate slag and metal, gas flow rates, and depths of both fluids. A mechanistic model for eye size was developed from fundamental fluid flow considerations. The model expresses a dimensionless eye area in terms of a density ratio of the fluids and a Froude number. The model is consistent with the present experimental results and those of others in different liquid systems. Finally, previously published correlations for eye size have been critically evaluated.

Effect of Bottom Bubbling Conditions on Surface Reaction Rate in Oxygen–Water System

“…In order to quantify the surface reaction rate at the plume eye area ((Ak) p ; m 3 /s), polystyrene particles were used to cover the outer area of the plume eye, following which the deoxidation rate was measured. Previously, viscous oil was used to cover the surface in the water model [8][9][10] ; however, the emulsified oil particles in water adhered to the oxygen sensor and disturbed the measurements. Therefore, polystyrene was used in this experiment.…”

An Extended Model for Slag Eye Size in Ladle Metallurgy

“…This is because the flow phenomena in the bulk liquid under conditions typical of ladle metallurgy practice are turbulent, and viscous forces are only of secondary importance in gas-stirred systems. 6,7) The available experimental data from recent studies 4,5) indicate that the viscosity of the upper phase has little appreciable effect on the steady state eye sizes. Apparently, viscous dissipation effects and drag between the phases under the flow configurations in the eye formation process are relatively small.…”

“…It was shown previously that the effect of interfacial tension between the liquids is only minor. 5) Due to the relatively large length scales in the eye formation process, the forces arising from interfacial tension are very small in comparison with the effects of inertia and gravity. Thus, interfacial tension is excluded from the analysis.…”

“…The formation of the eye has been the subject of some investigations in the recent past. [1][2][3][4][5] In modern ladle metallurgy practice, the eye and its central spout portion raised above the bath level are some of the few regions where molten steel is directly exposed to the ambient environment. These are sites for reactions like Oxygen and Nitrogen pick up.…”

“…Such models of the eye sizes may also be useful for process design considerations. With this aim, a previous mechanistic model of slag eye formation 5) is extended in a new mathematical model to quantify the eye size directly from the plant operating variables. The technique of dimensional analysis as well as analysis of published eye size data from several liquid-liquid systems have been employed in the derivation of the model.…”