Abstract

MABENTSELA, A.; AKDOGAN, G.  and  BRADSHAW, S.. Numerical and physical modelling of tundish slag entrainment in the steelmaking process. J. S. Afr. Inst. Min. Metall. [online]. 2017, vol.117, n.5, pp.469-483. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2017/v117n5a9.

Physical and numerical modelling methods were followed to identify mechanism(s) for tundish slag entrainment in a bare tundish and one with a flow control device (FCD). The physical and numerical models made use of water and paraffin to model steel and slag respectively. Observations from the physical model showed that the steel-slag interface remains immobile in both cases. Entrained paraffin formed droplets approximately 1 mm in diameter. Results from both models (numerical and physical) showed that in both cases (bare and FCD case), areas of high entrained slag concentration exist near the inlet region. The entrained slag concentration decreases towards the tundish endwalls. Flow patterns and velocities tangential to the steel-slag interface from the numerical model showed that slag entrainment in both the bare tundish and tundish with a FCD possibly takes place via two mechanisms. First, the slag moves across the steel-slag interface via mass transfer; secondly small velocities tangential to the interface at depths greater than 10 mm below the interface carry the already 'entrained' slag into the bulk steel phase. These tangential flow patterns are dominant in the inlet region, hence the high concentration of entrained slag in this region.

Keywords : tundish slag entrainment; tundish slag behaviour; numerical modelling; slag shearing.

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