Effects of Cr2O3 addition on property improvement of magnesia-spinel refractories used in RH snorkel

The Ruhrstahl-Heraeus (RH) snorkel is one of the most important parts of the RH furnace, which is the primary facility for producing high-quality steel. The magnesia-spinel refractory is the ideal replacement for the classic magnesia-chrome refractory in the RH snorkel. In this study, the effects of Cr2O3 addition (0-3 wt%) on properties of magnesia-spinel refractories were investigated. It was found that the addition of Cr2O3 results in the acceleration of the densification process and a decrease in the cold strength as well as a significant increase in the hot modulus of rupture. Thus, the solid solution formed with the spinel significantly improves the resistance to thermal shocks, with the greatest improvement being observed after the addition of 2 wt% Cr2O3.