MgO is known for its ability to matte glazes in larger proportions, though the mechanism for this is different at higher temperatures and low temperatures. Magnesium oxide is mainly obtained from dolomite and talc at medium and high temperatures; it is sourced mainly from dolomite and talc.
But more magnesium oxide is currently produced from the calcination of naturally occurring minerals. Magnesite (MgCO3) is the most common natural source of magnesium oxide.
Other essential sources include seawater, underground deposits of brine, etc. Research shows that magnesium is the eighth-most abundant element in the earth’s crust, comprising about two percent of the earth’s crust, as well as 0.12% of seawater. Magnesium oxide performs excellently in high temperatures, particularly in the provision of electrical insulation.
The MgCO3 and Mg(OH)2 obtained from the mineral sources of magnesium oxide are converted to the oxide by calcination. The thermal treatment during the calcination process typically affects the surface area and pore size of the magnesium oxide formed. Consequently, the reactivity of oxide is equally impacted. But the level and nature of impurities present in the calcined material depend on the source of the mineral.
Different types of magnesium oxide can be obtained depending on the temperature used during the calcining process. For example, dead-burned magnesium is produced at temperatures over 1500 degrees Celsius, while fused magnesia is obtained from calcined magnesia at temperatures over 2650C degrees Celsius.