Magnesium oxide (MgO), or magnesia supplier Distributor Manufacturer in Kolkata india
Magnesium oxide (MgO), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + H2O → Mg(OH)2), but it can be reversed by heating it to separate moisture.
Magnesium oxide was historically known as magnesia alba (literally, the white mineral from magnesia – other sources give magnesia alba as MgCO3), to differentiate it from magnesia negra, a black mineral containing what is now known as manganese.
While "magnesium oxide" normally refers to MgO, magnesium peroxide MgO2 is also known as a compound. According to evolutionary crystal structure prediction,[8] MgO2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and a semiconducting suboxide Mg3O2 is thermodynamically stable above 500 GPa. Because of its stability, MgO is used as a model system for investigating vibrational properties of crystals.
Applications
MgO is prized as a refractory material, i.e. a solid that is physically and chemically stable at high temperatures. It has two useful attributes: high thermal conductivity and low electrical conductivity. "By far the largest consumer of magnesia worldwide is the refractory industry, which consumed about 56 % of the magnesia in the United States in 2004, the remaining 44 % being used in agricultural, chemical, construction, environmental, and other industrial applications." MgO is used as a basic refractory material for crucibles.
It is a principal fireproofing ingredient in construction materials. As a construction material, magnesium oxide wallboards have several attractive characteristics: fire resistance, termite resistance, moisture resistance, mold and mildew resistance, and strength.
Niche uses
MgO is one of the components in Portland cement in dry process plants.
Magnesium oxide is used extensively in the soil and groundwater remediation, wastewater treatment, drinking water treatment, air emissions treatment, and waste treatment industries for its acid buffering capacity and related effectiveness in stabilizing dissolved heavy metal species.[according to whom?]
Many heavy metals species, such as lead and cadmium are most soluble in water at acidic pH (below 6) as well as high pH (above 11). Solubility of metals affects bioavailability of the species and mobility soil and groundwater systems. Most metal species are toxic to humans at certain concentrations, therefore it is imperative to minimize metal bioavailability and mobility.
Granular MgO is often blended into metals-contaminated soil or waste material, which is also commonly of a low (acidic) pH, in order to drive the pH into the 8–10 range where most metals are at their lowest solubilities. Metal-hydroxide complexes have a tendency to precipitate out of aqueous solution in the pH range of 8–10. MgO is widely regarded as the most effective metals stabilization compound when compared to Portland cement, lime, kiln dust products, power generation waste products, and various proprietary products due to MgO's superior buffering capacity, cost effectiveness, and ease/safety of handling.
Other uses
As a food additive, it is used as an anti-caking agent. It is known to the FDA for cacao products; canned peas; and frozen dessert.It has an E number of E530.
It is used as a reference white color in colorimetry, owing to its good diffusing and reflectivity properties. It may be smoked onto the surface of an opaque material to form an integrating sphere.
It is used extensively as an electrical insulator in tubular construction heating elements. There are several mesh sizes available and most commonly used ones are 40 and 80 mesh per the American Foundry Society. The extensive use is due to its high dielectric strength and average thermal conductivity. MgO is usually crushed and compacted with minimal airgaps or voids. The electrical heating industry also experimented with aluminium oxide, but it is not used anymore.
It is also used as an insulator in heat-resistant electrical cable.
MgO doping has been shown to effectively inhibit grain growth in ceramics and improve their fracture toughness by transforming the mechanism of crack growth at nanoscale.