Uses of Magnesium Oxide

Magnesium oxide is formed by an ionic bond between a magnesium and an oxygen atom. Its empirical formula is MgO. It is formed by the burning of magnesium ribbon which oxidizes in a bright white light and results in a powdered form. Magnesium oxide is hygroscopic in nature and should be protected from moisture. It is commonly found in Monte Somma (Italy), Crestmore (California, USA) and Varmland (Sweden).

Physical Characteristics

The physical characteristics of magnesium oxide are as follows:

• It is colorless but sometimes available in white, gray, yellow, brown or black colors.
• Its luster is vitreous to adamantine in nature.
• Its cleavage is in three directions, forming cubes.
• Its specific gravity and hardness is 3.6 and 5.5 respectively.
• It is transparent from 300 nm to 7 µm and has 1.72 refractive index at 1 µm.
• The crystal structure of MgO matches the crystal structure of NaCl (sodium chloride or salt), which has simple cubic packing and produces cubic and octahedral crystals.
• As a construction material, it has several attractive characteristics: fire and moisture resistance, mold and mildew resistance, and strength.

Some of its associated minerals include brucite, hydromagnesite, forsterite, dolomite, magnesite and chondrodite.

Uses of Magnesium Oxide

Some of the common uses of magnesium oxide are as follows:

1. It is used in libraries for preserving and deacidifying books, as it reacts with ambient moisture to dry the book storage areas.
2. It is used as a medication to relieve heartburn, sour stomach and acid indigestion.
3. It is also used as a short-term laxative and to supplement a diet with magnesium. It also reduces the symptoms of indigestion.
4. Magnesium oxide is used as an insulator in industrial cables and devices that exhibit the tunnel magnetoresistance effect.
5. It is a principle ingredient in construction materials and hence used for fireproofing.
6. It is also used as a basic refractory material for lining crucibles.
7. MgO is used as one of the raw materials for making cement in dry process plants; specifically Portland cement.
8. It is used to reduce sweat and moisture on the hands and holds by rock climbers.
9. Due to its excellent diffusing and reflectivity properties, it is used as a reference white color in colorimetry. If smoked onto the surface of an opaque material, it forms an integrating sphere.
10. Due to its high dielectric strength and average thermal conductivity, it is used extensively in electrical heating as a component of "CalRod"-styled heating elements. Different mesh sizes are available but the most commonly used ones are 40 and 80 mesh - as per the American Foundry Society.
11. MgO is also used in feeding animals and there are special grades available for it.
12. It is used in leather processing, as a basifying agent on chrome tanning process.
13. The crystalline pure form of MgO is used in infrared optics.
14. It is used to control the solubility of radionuclides. Therefore, it is packed around the transuranic waste at the Waste Isolation Pilot Plant.

Side Effects

Side effects of magnesium oxide include nausea and cramping. Long term intake of MgO causes enteroliths which finally results in bowel obstruction. Inhalation of magnesium oxide smokes can cause metal fume fever. A person suffering from any kind of kidney disease should avoid intake of magnesium oxide. It is not advisable for pregnant or breast-feeding mothers to consume MgO without consulting a doctor.

Due to its excellent physical properties and numerous applications, magnesium oxide is the most commonly used form of magnesium. Its intake is beneficial for the body especially muscles and nerves, but should only be done under a doctor's supervision to avoid any side effects.