Magnesium oxide (MgO). An inorganic compound that occurs in nature as the mineral periclase. In aqueous media combines quickly with water to form magnesium hydroxide. Magnesium oxide is used as an antacid and mild laxative and has many nonmedicinal uses.
Because of its high melting point, magnesium oxide finds many uses which apply its refractory properties, so it can be used as a furnace lining and in crucibles. It is also used for fireproofing boarding for panelling walls.
Magnesium oxide is a popular drying agent. In powder form, it is hygroscopic in nature, meaning that it attracts water molecules to itself from its surrounding environment. In doing this, the magnesium oxide will pull those molecules away from other things, keeping them dry.
Libraries and other large book and paper storage facilities will often use powdered magnesium oxide to help preserve paper. Rock climbers often use magnesium oxide as a way to reduce moisture from perspiration on their hands and handheld equipment, though other mineral powders are also used for this purpose.
Magnesium oxide is used as a refractory agent in the construction of crucibles. A crucible is a container which is intended to be placed in extremely high temperatures for the sake of heating its contents. Since the crucible itself must not be affected by the heat, it must be made with substances which retain their properties at high heat. Magnesium oxide is such a substance, so it is used in this manner.
Due to these same heat-resistant properties, magnesium oxide powder makes an excellent insulator. It is used as the mineral component of mineral-insulated copper-clad cables, a form of industrial cable used for the protection of particularly critical electrical circuits during a fire, including fire protection devices such as alarms or smoke control systems.
Since it is a good source of magnesium, magnesium oxide is used as or in dietary supplements for humans and animals. In the case of animals, this is delivered as a food additive. For humans it can come in pill form or be included in multivitamins.
Magnesium oxide is often used in optical applications due to its refractive index (light-reflecting properties) in crystal form. Its basic properties are also utilized in the treatment of leather and its hygroscopic properties in the packaging of nuclear waste.
|Identification||To pass test|
|Free alkalies||soluble salts 2.0% max|
|Heavy Metals||20 ppm max.|
|Lead||.5 ppm max.|
|Loss on ignition||10% max.|