A computational fluid dynamic modeling study of slag fuming in top submerged lance smelting furnace

Slag fuming is a process of extracting zinc from molten slag in the form of metal vapor by injecting or adding a reducing source such as pulverized or lump coal, natural gas, etc. Top Submerged Lance (TSL) technology has been successfully applied to extract zinc by a fuming process from residues from the zinc industry, ISF and QSL slag and Lead blast furnace slag. A Computational Fluid Dynamic model has been developed for zinc slag fuming process from ISF slag to investigate details of fluid flow and heat transfer in the furnace. The models integrate complex combustion phenomena and chemical reactions with the heat, mass and momentum interfacial interaction between the phases present in the system. The model is based on 3-D Eulerian multiphase flow approach and it predicted the velocity and temperature field of the molten slag bath and side wall heat fluxes. The model also predicted the mass fractions of slag and gaseous components inside the furnace. The model confirmed that rate of zinc fuming increases with temperature and is broadly consistent with experimental data.