Magnesia carbon bricks are made of fused magnesia, high purity magnesia and flaky graphite as main raw materials, and non-carbonaceous basic refractories which made of phenolic resin as binder. The production process is basically the same as that of ordinary refractory bricks, but it does not need to be fired, and only needs to be heat treated at 200-250 °C. When magnesia carbon bricks are used in high temperature, carbon bonding is formed. There is no mutual solubility between magnesia and carbon materials in refractory materials. Magnesia sand and graphite keep their own characteristics and complement each other's shortcomings, so that magnesia carbon bricks have excellent slag corrosion resistance, slag resistance and thermal shock resistance.

Magnesia carbon bricks are divided into four types according to the carbon content:

(1) C 5%， MgO 82%-85%。

(2) C 10%，MgO 76%-80%;

(3) C 14%，MgO 74%-76%;

(4) C 18%，MgO 70%-72%;

It is used in the slag line parts of various ladle refining furnaces. Magnesia carbon bricks are generally used with a lower carbon content (w(C) <14%)

The excellent slag resistance, corrosion resistance and thermal shock resistance of magnesia carbon bricks depend to a great extent on the role of graphite. Graphite can effectively prevent the penetration of slag, increase the thermal conductivity of the brick and reduce the elastic modulus of the brick. However, the increase of graphite content will reduce the strength and oxidation resistance of bricks. When graphite content is 10%~20%, magnesia carbon brick has the best corrosion resistance. The grain size of the periclsite has a great influence on the erosion resistance of the magnesia carbon brick. Because the grain size of fused magnesia is larger than that of sintered magnesia, magnesia carbon bricks are often used fused magnesite.