Chemical degradation of magnesia–carbon refractories by different gaseous atmospheres

Abstract

In this work, we use a novel methodology to analyse how the critical compositional variables of MgOC bricks affect their chemical degradation by oxygen attack; the study focuses on the effect of the graphite content, the presence of aluminium, and the binder type. Oxidation tests are performed at 1000 °C, a typical preheating condition for steelmaking ladles, under two atmospheric conditions: one simulated the oxygen concentration in air, and the other, with a lower amount of oxygen, reproduces the conditions of the inner part of the brick when liquid steel is present. It was found that: a) the addition of Al reduces the carbon oxidation kinetic, mainly at a low O2 partial pressure, b) increasing the graphite content led to a smaller decarburized area with higher O2 consumption, and c) mixing CarboRes® with phenolic resin resulted in a higher O2 consumption but at a slower oxidation rate.

Keywords

• MgO-C refractories
• Oxidation
• Antioxidant
• Graphite
• Organic binder
• Material applications