Slag-steel emulsification on a modified RH degasser.

Abstract

A new arrangement of RH snorkels is proposed in order to improve the slag metal interaction. According to this RHDeS design, the steel jet flowing down from the vacuum chamber discharges inside the slag layer. Physical modeling of a reactor following this concept was performed. Mixing times, circulation rates, and the mass transfer coefficient were evaluated as well as the droplet residence time. Mixing times and overall circulation are not very much affected by the modifications. However, the modification brings about a large and sustainable dispersion of slag (oil) in metal (water). The influence of this dispersion on de-S was assessed. A lumped kinetic parameter KA=vw was evaluated in order to quantify the process kinetics. Kinetics can be improved by one order of magnitude. It is suggested that proper slag (amount and basicity) allied to this geometric modification could be fruitful to sulfur removal from deoxidized steel. Simulations show that sulfur removal with this RHDeS arrangement is expected to be higher than with schemes where de-S reagents are added in the vacuum chamber.