Effects of Graphite Content on the Oxidation Resistance of MgO-C Refractory Bricks

The effects of graphite content on the density and oxidation behavior of MgO-C refractory samples were studied. The samples were formulated with various amounts of graphite and their oxidation behavior was investigated (in an isothermal condition); using a Thermo Gravimetric system (TG), in air and at temperatures ranging from 900\degree C to 1450\degree C. The preliminary results showed that the porosity and density of tempered samples were decreased when the graphite content was increased. However, after heating the samples at higher temperatures, the decreasing rate of porosity was lowered. At the beginning of the oxidation process, the rate of weight loss was high, but was gradually decreased when the thickness of the decarburized layer increased. The overall results indicated that although the higher graphite content increased the weight loss, it reduced the thickness of the oxidized layer.