Magnesia brick is a basic refractory product with periclase as its main mineral phase. It contains not less than 91% MgO and not less than 3.0% CaO.

Magnesia brick is composed of 80-90% periclase and 8%-20% other mineral phase including magnesium ferrite (MgO·Fe2O3), forsterite (2MgO · SiO2) and Calcium and magnesium olive stone (CaO·MgO·SiO2).Silicate glass contains about 3-5% magnesium, calcium and iron. These silicates may contain tricalcium silicate (3CaO · SiO2), magnesium rhodonite (3CaO · MgO · 2SiO2), calcium and magnesium olivine and forsterite, dicalcium silicate (2CaO · SiO2).

Magnesia brick has good thermal conductivity, good thermal expansion, good corrosion resistance to alkali molten slags and bad corrosion resistance to acid molten slags. Due to the low-melting silicate cements surrounded periclase, the beginning point of the softening temperature under load is not too high, but the collapse temperature is close to the beginning point. Its refractoriness is over 2000℃, but it does not make sense in the actual use. Bad thermal shock stability is one of the main reasons for the destruction.

In the storage and transport, special attention should be paid to moisture-proof to avoid burst after affected with damp.