Slag foaming in the bath-smelting process

The purpose of the present study was to experimentally investigate the effects of bubble size, carbonaceous particles and pressure on foam stability and to develop a theoretical model to predict slag foaming in the bath-smelting process.;The average bubble diameter increased from 1 mm at 0.002% sulfur to more than 5 mm at 0.1% sulfur content in the metal phase. Sulfur decreases the surface tension of the metal phase. The slag/metal interfacial tension decreased as the sulfur content in the metal phase increased and the contact angle also increased. The size of the CO gas bubble detaching from the slag/metal interface is determined by the contact angle: The higher the contact angle, the larger the bubble size.;Both coke and coal char particles have an anti-foam effect on liquid slag. X-ray examinations indicated that the antifoam effect of these particles is primarily contributed by the non-wetting nature of the carbonaceous material with the liquid slag.;The foam index calculated based on the results of the present work can be used to predict the foam height in the bath-smelting vessel. The predicted result was in good agreement with the pilot plant data. (Abstract shortened with permission of author.).;In this study, slag foams for a bath-smelting type of slag,...