Magnesium oxide

Magnesium oxide (MgO), also known as magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium. It has an empirical formula of MgO and consists of a lattice of Mg²⁺ ions and O²⁻ ions held together by ionic bonding. Magnesium oxide is commonly used as an antacid and a laxative. When mixed with water, it is referred to as milk of magnesia, which has many medicinal uses. Additionally, MgO is utilized in agriculture, in the manufacture of refractory materials, and as a fire retardant.

Properties

Magnesium oxide is a basic oxide with a high melting point of 2,852°C (5,166°F) and is insoluble in water. It is one of the most thermally stable and electrically insulating oxides, making it extremely useful in fields requiring high-temperature resistance. Its thermal conductivity is also significantly lower than other ceramics, contributing to its use in fireproofing and thermal insulation.

Production

The production of magnesium oxide predominantly involves the calcination of magnesium carbonate or the thermal decomposition of magnesium hydroxide or magnesium chloride in the presence of air or steam. This process releases carbon dioxide from magnesium carbonate or water from magnesium hydroxide, leaving behind pure magnesium oxide.

Applications

Medicine

In the medical field, magnesium oxide is widely used for its antacid properties, providing relief from symptoms of heartburn and indigestion by neutralizing stomach acid. As a laxative, it draws water into the intestines, promoting bowel movements. It is also used as a dietary supplement for individuals with magnesium deficiency.

Agriculture

In agriculture, magnesium oxide serves as a magnesium supplement in animal feeds and fertilizers to correct magnesium-deficient soils.

Industry

Industrially, MgO is used in the production of refractory bricks and materials that can withstand high temperatures without melting. These are critical in furnaces, kilns, and reactors. Additionally, its fire retardant properties make it suitable for use in cables, electrical insulation, and construction materials.

Health and Safety

While magnesium oxide is generally considered safe for consumption in controlled doses, excessive intake can lead to hypermagnesemia, a condition characterized by an abnormally high level of magnesium in the blood, which can cause serious health issues. In industrial settings, inhalation of magnesium oxide fumes or dust can irritate the respiratory tract.

Environmental Impact

Magnesium oxide production can have environmental impacts, particularly through the release of carbon dioxide during the calcination of magnesium carbonate. However, efforts are being made to capture and utilize CO₂ emissions more effectively, reducing the carbon footprint of MgO production.

See Also

• Magnesium
• Magnesium carbonate
• Magnesium hydroxide
• Refractory materials