In-situ observation of dynamic interfacial phenomena between CaO-(SiO2 or Al2O3) slag and Fe-11%Cr alloy near the MgO-6%C refractory at 1823 K

We investigated dynamic interfacial phenomena at the slag-metal-refractory three-phase interface using a high temperature X-ray radiographic technique. Dynamic movement of the metal-slag line between Fe-11%Cr alloy and CaO-(SiO2 or Al2O3) slag was observed near the MgO-6%C refractory at 1823 K. We observed corresponding local corrosion of the refractory with CaO-SiO2 slag but it was negligible with CaO-Al2O3 slag. From a thermodynamic perspective, the Marangoni convection at the slag-metal-refractory interface is not the dominant factor determining the corrosion rate of the MgO-C refractory. Rather, it is the large solubility limit and the mass transfer in the slag phase.