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.