Mechanism of Dense Magnesia Layer Formation near the Surface of Magnesia‐Carbon Brick

After operation of a basic oxygen furnace with a MgO-C brick lining, formation of a dense MgO layer is observed near the working surface. It is affected by soak atmosphere gas in the first stage of operation. As operation of the furnace proceeds, the MgO-C brick being submitted to cyclical heating and cooling, internal oxidation-reduction reactions of MgO and C occur. As a result, needlelike crystals of MgO grow at the interface between the dense MgO layer and the original layer, resulting in further growth of the densi MgO layer.