Magnesium oxide is the main component of magnesia. The impurities of regenerative bricks are CaO, SiO 2, FeO 3, etc. Magnesium oxide is an alkaline oxide with a melting point of 2800 degrees. After being heated at high temperature, it is transformed into a stable cubic crystal, commonly known as periclase. Magnesium hydroxide is calcined at high temperature and has strong hydration resistance.
Magesite is divided into three categories: sintered magnesite, lightly burned magnesite and fused magnesite. Magnesia is one of the most important raw materials for refractories. It is used to manufacture various magnesia bricks, magnesia-alumina bricks, ramming materials, furnace feeding materials and so on. Containing more impurities, it is used to pave the bottom of the steelmaking furnace, etc. Calcination or electrofusion of natural magnesite, extraction from sea water, Salt Lake brine, and extraction from dolomite, serpentine and brucite. At present, magnesia is mainly obtained from magnesite calcination or electrofusion in China, while it is mainly extracted from seawater in Japan and Western European countries.