Functional Spinel-Binder Based Additives for Improved MgO–C Performance in Ladle Applications
They have to withstand aggressive steel/slag systems in the range of 1600–1750 °C and also provide an excellent thermal shock performance. During service or pre-sintering, alumina is able to react with magnesia to form spinel. In order to improve thermomechanical and chemical performance MA-spinel raw materials alumina-rich spinel and highly reactive spinel binder/clinker have been introduced in the composition. The impact of spinel or spinel forming phases on physical and thermomechanical properties as well as corrosion resistance has been found to depend on the grain size, chemistry, and amount of added raw materials. In order to implicate and reflect the influence of spinel formation on material properties the carbonization temperature has to be above common 1000 °C. Two different pre-reacted coarse- and fine-grained MA-spinel raw materials were added to common MgO–C with 3 mass-% C (after carbonization) and carbonized at 1000 °C and 1400 °C respectively. Thus, improved MgO–MgAl2O4–C samples with pre-reacted and in situ formed spinel for application in steel ladles were produced. Material properties like cold crushing strength (CCS) and thermal shock resistance, microstructure, and phase composition have been analysed.