Magnesium oxide is an oxide of magnesium, an ionic compound. It is a white solid at room temperature. Magnesium oxide exists in nature in the form of periclase and is the raw material for magnesium smelting. Magnesium oxide has high refractory and insulating properties. It can be transformed into crystals by high temperature burning above 1000 C, and sintered magnesia (magnesia) or sintered magnesia when it rises to 1500 - 2000.
Magnesium oxide exposed to air is easy to absorb water and carbon dioxide and gradually become basic magnesium carbonate. Light products are faster than heavy products. Magnesium hydroxide is formed by combining with water under certain conditions, which is slightly alkaline. The pH of saturated water solution is 10.3. Soluble in acid and ammonium salt, insoluble in water, its solution is alkaline. It is insoluble in ethanol. It has strong refractivity in the visible and near-ultraviolet light range.
Magnesite (MgCO3), dolomite (MgCO3. CaCO3) and seawater are the main raw materials for the production of magnesium oxide. Magnesium oxide is obtained by thermal decomposition of magnesite or dolomite. Magnesium hydroxide is precipitated from seawater treated with lime, and magnesium hydroxide is obtained by burning magnesium hydroxide. Magnesium hydroxide or basic magnesium carbonate can also be precipitated from magnesium chloride brine or brominated brine obtained from comprehensive utilization of seawater by adding sodium hydroxide or sodium carbonate, and then calcined to obtain magnesium oxide.
One of the main uses of magnesium oxide is as a flame retardant. Traditional flame retardant materials widely use halogen-containing polymer or halogen-containing flame retardant mixture.
With the upgrade of industrialization and the demand and development of high-tech functional materials market, a series of high-tech and fine magnesium oxide products have been developed and produced, which are mainly used in nearly ten varieties, such as high-grade lubricants, high-grade tanning alkali extraction, food-grade, medicine, silicon steel grade, high-grade electromagnetic grade, high-purity magnesium oxide and so on.