Measurement and physical model prediction on splash fluxes in a pilot TSL bath smelting furnace

Abstract

Top Submerged Lance (TSL) furnaces used for non-ferrous smelting have high heat and mass transfer rates due to the intensive stirring and splashing generated by the lance. While splashing can cause accretion build-up in the upper cooler regions of the furnace, it plays an important role in heat and mass transfer and needs to be controlled to minimise accretion formations while maximising furnace productivity. In this work, splashing was studied by measuring the splash flux from a molten slag bath in a 300 kg pilot-scale TSL furnace and also from an ambient temperature aqueous-glycerol solution bath in a physical model. In both systems, total injection gas flowrate, lance immersion depth and splash height were examined to determine their effects on the splash flux. An empirical correlation was developed based on the results of the aqueous-glycerol physical model using the methodology of dimensional analysis. This correlation was then used to predict the splash for high temperature smelting conditions. Comparison of the predictions with both hot and cold experimental measurements showed the same variation trends and the predicted values were within an acceptable range, particularly in splash heights within 1 m above the bath surface and at medium to high gas flowrates with lance immersion depths being 1/6–1/3 of the bath height. It is concluded that the correlation can be potentially applied to predict splashing behaviour in TSL furnaces.