Enhanced slag resistance and mechanical properties of magnesia castables with strontium carbonate addition

Magnesia castables have been widely used in metallurgical industries with the advantages of high refractoriness, non-polluting steel, and resistance to alkaline slag. Magnesia castables were prepared using strontium carbonate (SrCO 3 ) as additive to enhance slag resistance and mechanical properties, and the influence of SrCO 3 on the evolution of phases, microstructure and properties of magnesia castables sintered at different temperatures was clarified. The results show that, with the introduction of SrCO 3 (lower than 3 wt.%), elastic modulus, mechanical strength, thermal shock resistance and densification of magnesia castables were significantly enhanced owing to the formation of needle-like Ca 0.9 Sr 0.1 MgSi 2 O 6 phase and liquid phase when sintering at high temperatures, and the introduced SrCO 3 presented minor effects on the mechanical properties of castables for its highly structural stability below 1100 °C. During the slag corrosion process, SrCO 3 and SiO 2 in castables reacted with Al 3+ in molten slag to form SrAl 2 SiO 8 phase, resulting in the increased slag viscosity and suppressed continuing penetration.