Evaluation of Bubble Eye Area to Improve Gas/Liquid Reaction Rates at Bath Surfaces

Abstract

In ladle refining operations, a plume eye is the of the bath surface that is not covered with slag, due to bubbling gas, and this is the most important in slag-metal reactions. In contrast, in vacuum degassers, most of the surface is not covered with slag, and in this case, the rising at the bath surface is important for gas-metal reactions. This is referred to as the bubble eye area in this paper. To evaluate the eye size, and its effect on the surface reaction rate, water model experiments were carried out. The plume eye size was measured by changing the thickness of a polystyrene particle layer, which was added to the surface as a slag layer. The eye size was estimated by extrapolating the plume eye size to the value calculated for a polystyrene layer thickness of zero. The volumetric mass transfer coefficient of the surface reaction was measured at various size of plume eye. The volumetric mass transfer coefficient at the eye was evaluated by extrapolating the mass transfer coefficient at the plume eye to the value calculated for a plume eye size equal to the eye size. It was concluded that the size of the eye is influenced by the gas flow rate through each nozzle, whereas the volumetric mass transfer coefficient at the eye is influenced by the eye and the rising velocity.