The interface in slag reactions: a moving target

A knowledge of surface area is key to modeling the kinetics of many high temperature processes. In the case of reactions with slags the surface area may change during the course of the reaction in ways that we are currently not able to predict. In the current paper the authors discuss three examples from their own work and highlight the progress made and challenges still to be addressed. In the case of reaction of single metal droplets with slags, it is shown that the free energy provided by the reaction can be correlated directly with surface area. No explanation is offered for this phenomenon because the free energy involved is several orders of magnitude greater than that required to create a new surface. In the case of droplet generation in the BOF and carbon injection into slag the active surface is a balance between that created and the time for it to be annihilated or become inactive. In the case of the BOF we now have a good understanding of droplet generation and on-going work to predict droplet residence time is described. The interface in slag reactions is certainly a moving target but there is good reason to expect progress in this area.