Evaluation of oxidation resistance of MgO-C bricks in oxy-combustion and air-combustion

There are important advantages in oxy-fuel technology over conventional combustion, such as the reduction in fuel consumption and gaseous emissions. However, before its use in the steel industry, it is essential to know that the alteration of the firing system can lead to an increase in the wear of the oxide-carbon refractories. In the present work, four types of MgO-C bricks were fired under oxy-fuel and air-fuel conditions in a semi-industrial furnace, simulating the heating of a steelmaking ladle. The fired bricks were evaluated in terms of weight loss, thickness of the decarburized layer, and phases and microstructure formed in this layer. The results indicated few differences in the properties of the bricks fired in the two systems. The brick with 12% carbon and Al antioxidant showed the highest oxidation resistance among all bricks investigated. The most important factor for the use of the oxy-fuel system was the correct selection of the refractory microstructural properties, including the utilization of antioxidant additives.