Effects of rare earth oxides additions on microstructure and properties of alumina-magnesia refractory castables

To accommodate the glaring requirements of castables with high performances for the iron and steel making industry, effects of rare earth oxides additions on microstructure and properties of alumina-magnesia refractory castables were investigated. The properties of castables including phase compositions, apparent porosity, permanent linear change and strength were compared. It was demonstrated that yttria and ceria presented varying degrees of influence on in-situ reactions and volumetric stability of castables. The solid-soluted content of spinel and calcium hexaluminate (CA6) was both dependent on the additions.