There are two kinds of brick-making methods for magnesia-carbon bricks: fired oil-impregnated magnesia-carbon bricks and unburned magnesia-carbon bricks. The former brick-making process is more complicated and is rarely used. Here, only the characteristics of the brick-making process of unburned magnesia-carbon bricks are briefly described.
Sludge preparation: The choice of critical particle size is important during breeding. Refinement of aggregate particles can reduce open porosity and enhance antioxidant capacity. However, the small aggregate particles will increase the closed pores and reduce the bulk density. In addition, fine-grained MgO aggregates are easy to react with graphite, and it is generally considered that the particle size of 1 mm is suitable. In the presence of high-pressure molding equipment, the particles of magnesia tend to be finer. The pressure of molding equipment in my country is low. In order to increase the density of refractory bricks, many manufacturers use particle diameters of more than 5mm.
Magnesia-carbon bricks are made of high melting point alkaline oxide magnesia (melting point 2800°C) and high melting point carbon materials that are difficult to be infiltrated by slag as raw materials, and various non-oxide additives are added. A non-charcoal composite refractory material combined with a carbon binder.
Magnesia-carbon bricks are mainly used in converters and AC electric arc furnaces.