The freeze lining of an industrial copper flash smelting furnace slag, its growth kinetics and microstructure have been studied using a water cooled probe technique in a rotating crucible furnace at 1350uC. The first layers of iron silicate slag solidify on the water cooled metal surface as amorphous or glassy material with a minor fraction of crystalline spinel phase precipitated. At a distance of 4-5 mm from the cold face about 50% of the structure is composed of crystalline olivine (fayalite) and spinel phases embedded in a glassy matrix. Major thickness of the freeze lining is formed within first 15 min of slag contact with a cooled metal surface. The solidified microstructures obtained were compared with equilibrium phase assemblages calculated. The equilibrium solidification in the near solidus reactions includes the formation of pyroxene and rhodonite type phases, but they were not identified in the lining microstructures.

An advanced approach for modeling solidification, heat transfer, and fluid flow is used to study an industrial bloom caster with a bifurcated submerged entry nozzle. The advantage of this approach is the increased accuracy from using temperature‐dependent material properties and precise heat transfer boundary conditions. The computational domain encompasses the whole liquid pool and computational factors affecting the accuracy are analyzed. According to the results, severe shell thinning on the narrow faces is caused by impinging jets from the submerged entry nozzle, which are highly localized and affect the superheat distribution. Most of the superheat is dissipated in the mold, but the remainder is spread to a large area in the secondary cooling zone, which can only be investigated by coupled CFD models extending far enough. Heat transfer models based on the effective thermal conductivity method can be used to determine the end of the liquid pool and solid shell temperatures, but cannot capture the features of areas, where the liquid fraction is high.

No abstract

No abstract