The influence of B4C and MgB2 additions on the behavior of MgO–C bricks

Carbon-containing refractory materials have received great attention over the last years due to their importance in the steelmaking process. The oxidation of carbon present in refractory materials at temperatures above 500 °C is usually accompanied by the decrease of their mechanical strength and chemical resistance. Aiming to improve the oxidation resistance of carbon-oxide refractories, the use of materials known as antioxidants has been extensively studied. In this work we evaluated the performance of MgB2 and B4C antioxidants when incorporated into MgO–C bricks. We observed that the co-addition of metallic antioxidants and B4C or MgB2 leads to refractory bricks with enhanced hot modulus of rupture and resistance against oxidation and slag corrosion. However, the excessive addition of these antioxidants could impair the performance of the obtained bricks. Thus, when determining the optimum concentration of MgB2 and B4C to be added into MgO–C refractories, one must take into consideration this behavior.