CFD modelling of the combustion and heat transfer in the Top-Submerged-Lance smelter

The growth outlook for the circular economy in the metallurgical industry has to be built on the deep knowledge of the secondary processes involved in the chain: metal recycling and waste recov-ery play a significant role to successfully close the loop in the metal cycle.
The top-submerged-lance (TSL) furnace technology, primarily designed for metal extraction, is gradually making headway on that perspective because of its technical and economical flexibility. To push the market in that direction, an intense research effort has to be put in the understanding of the fundamentals, from chemical-physical to the engineering aspects.
In the present work, the authors investigate the lance combustion and the heat transfer in a TSL fur-nace. The submerged combustion is a crucial aspect of this technology. The correct design and ap-plication of the lance and the appropriate gas flow conditions must ensure a well-defined value of the partial pressure of oxygen pO2, which drives the smelting reaction process of the mineral con-centrate in the liquid slag bath.
A CFD investigation of the lab-scale TSL furnace, located at TU Bergakademie Freiberg, is per-formed using ANSYS Fluent®: the furnace setup includes the submerged combustive injection into a Cu-slag bath, in absence of the concentrate stream. The analysis provides detailed insights of the fuel combustion and the interaction with the liquid slag. Besides that, the evaluation of the pO2 at the lance tip and the temperature distribution in the bath and in the lance wall represent an added value for the furnace controlling and optimization.