Interaction Behaviors of MgO Refractory with CaO–SiO ₂ –FeO x –MgO–MnO–Al ₂ O ₃ –P ₂ O ₅ Slags

When recycling ladle slags in basic oxygen furnace (BOF) steelmaking, CaO–SiO 2 –FeO x –MgO–MnO–Al 2 O 3 –P 2 O 5 system BOF slags should be formed. To reveal the interaction behaviors of MgO refractory with this type of slag, laboratory experiments were conducted at 1480°C. The effects of Al 2 O 3 , FeO x , and basicity [ R = w (CaO)/ w (SiO 2 ), 1.0–2.0] on the interaction behaviors were discussed based on experimental results and thermodynamic calculations. It was found that an (Mg, Fe, Mn)O reaction layer was generated at the refractory‐slag interface, and it was thickened with time. The thickness of the reaction layer was determined by its formation (growth) and dissolution, and influenced by the FeO activity in the slag and the properties of the slag. A higher FeO content and a lower Al 2 O 3 content, as well as a higher level of slag basicity, would result in a thicker reaction layer. A suitable Al 2 O 3 content can lower the viscosity and melting point of BOF slag and enhance the dissolution of MgO refractory. FeO x also played a profound role in the formation of the reaction layer and slag properties. So, the control of FeO content in BOF slags would be crucial. When adding ladle slag in BOF converter, severe corrosion of refractory is not expected with a suitable slag composition.