**1.1.3 Magnesia (MgO)**

Magnesia is the most abundant one in refractory oxides and its melting point is 2800 0C. Its thermal expansion rate is very high. It can be reduced easily at high temperatures and evaporate at 2300-2400 0C. At high temperature levels, magnesia has resistance to mineral acids, acid gases, neutral salts and moisture. When contacted to carbon, it is stable up to 1800 0C. It rapidly reacts with carbons and carbides over 2000 0C. The most important minerals of magnesia are magnesite, asbestos, talc, dolomite and spinel.
