Where Found (Encyclopedia of Global Resources)
Magnesium is a widespread and abundant element. Magnesium chloride and magnesium sulfate are present in dissolved form in seawater and underground brines—these sources accounted for 43 percent of U.S. magnesium compound production in 2008. Magnesium is also found in many minerals, notably magnesite (MgCO3), dolomite (CaMg (CO3)2), and brucite (Mg(OH)2). China, Russia, Israel, Kazakhstan, Canada, and Brazil are among the main producers. For a number of years, the United States has withheld its magnesium production statistics to avoid disclosure of companies’ proprietary data.
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Primary Uses (Encyclopedia of Global Resources)
Technical Definition (Encyclopedia of Global Resources)
Magnesium (abbreviated Mg), atomic number 12, belongs to Group IIA of the periodic table of the elements (alkaline-earth metals). It has three stable isotopes and an average molecular weight of 24.312. Pure magnesium is a silver-white, ductile metal that is malleable when heated. A chemically active element, magnesium is a potent reducing agent. Its specific gravity is 1.738 at 20° Celsius, its melting point is 651° Celsius, and its boiling point is 1,100° Celsius.
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Description, Distribution, and Forms (Encyclopedia of Global Resources)
Magnesium in the form of powder or ribbons readily ignites when heated, burning with an intense white light and releasing large amounts of heat while forming magnesia (magnesium oxide, MgO). Magnesium reacts with organic halides to produce Grignard reagents, an important class of chemical compounds used in the laboratory.
Magnesium is an alkaline-earth metal, a class of hard, heavy metals that are strongly electropositive and chemically reactive. It is the eighth most abundant element; its concentration in the lithosphere is 20,900 grams per metric ton, and the percentage of its ions in seawater is 0.1272. Magnesium’s density (only two-thirds that of aluminum) and the ease with which the element can be machined, cast, forged, and welded contribute to its commercial applications, as do the refractory properties of some of its compounds. China is the leading producer of primary (mined and processed) magnesium (627,000 metric tons in 2007), accounting for nearly 85 percent of magnesium production in the world. Russia and Canada are the world’s other leading producers. However, from 2003 to 2007, Canadian production declined dramatically from 78,000 to 16,300 metric tons.
Magnesium is one of the most common minerals in the Earth’s crust; its principal commercial source, however, is seawater. Extensive terrestrial deposits of magnesium are also found in the form of magnesite and dolomite....
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History (Encyclopedia of Global Resources)
Sir Humphry Davy discovered magnesia in 1808. In 1828, Antoine Bussy isolated pure magnesium by chemical reduction of the chloride, and in 1833, Michael Faraday isolated magnesium electrolytically. The earliest commercial production of the metal may have been in France during the first half of the nineteenth century, where a modification of the Bussy method was employed. At this time, magnesium metal was used primarily in photography. Around 1886, Germany developed an improved production process based on an electrolytic cell method devised by Robert Bunsen in 1852. Germany became the world’s sole source for elemental magnesium. Magnesium alloys were used in Germany in the early 1900’s in aircraft fuselages, engine parts, and wheels. In 1915, when a wartime blockade of Germany by the British interrupted the elemental magnesium trade, magnesium production began in the United States. Large-scale use of dolostone as a refractory material also commenced during World War I. In 1941, Dow Chemical Corporation introduced its process for extracting magnesium from seawater.
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Obtaining Magnesium (Encyclopedia of Global Resources)
Magnesium is obtained principally from seawater through theDow seawater process. The water is treated with lime to produce magnesium hydroxide as a precipitate. This precipitate is mixed with hydrochloric acid to form magnesium chloride; the chloride, in turn, is fused and electrolyzed, producing magnesium metal and chlorine gas. From a liter of seawater, approximately 10 milligrams of magnesium can be extracted. Another common method for obtaining magnesium is the ferrosilicon (Pidgeon) process, which uses dolomite as a raw material. The dolomite is heated to produce magnesia, which is then reduced with an iron-silicon alloy.
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Uses of Magnesium (Encyclopedia of Global Resources)
Dead-burned magnesite, produced by heating the mineral in a kiln at 1,500° to 1,750° Celsius until it contains less than 1 percent carbon dioxide, is a refractory material. Able to withstand contact with often corrosive substances at high temperatures, refractory materials are used to line furnaces, kilns, reaction vessels, and ladles used in the cement, glass, steel, and metallurgical industries. Magnesia refractories are materials particularly suited for the basic oxygen furnaces used in steelmaking. Dead-burned dolomite, produced by heating dolostone or dolomitic limestone at about 1,500° Celsius, is also a refractory material used for lining metallurgical furnaces.
In its elemental state, magnesium is soft and weak; its alloys, however, are sturdier and have a variety of uses. Magnesium is used extensively as an alloy metal, particularly in combination with aluminum, zinc, cadmium, and manganese. Magnesium alloys in general are lightweight, fatigue-resistant, free from brittleness, and able to withstand bending stresses; these qualities make magnesium alloys ideal for jet-engine parts, rockets and missiles, luggage frames, cameras, optical instruments, scientific equipment, and portable power tools. Duralumin, a lightweight alloy of aluminum, copper, magnesium, and manganese, is ductile and malleable before its final heat treatment; afterward, its hardness and tensile strength are increased. Its properties make...
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Further Reading (Encyclopedia of Global Resources)
Friedrich, Horst E., and Barry L. Mordike, eds. Magnesium Technology: Metallurgy, Design Data, Applications. New York: Springer, 2006.
Greenwood, N. N., and A. Earnshaw. “Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium.” In Chemistry of the Elements. 2d ed. Boston: Butterworth-Heinemann, 1997.
Henderson, William. “The Group 2 Elements: Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium.” In Main Group Chemistry. Cambridge, England: Royal Society of Chemistry, 2000.
Kogel, Jessica Elzea, et al., eds. “Magnesium Minerals and Compounds.” In Industrial Minerals and Rocks: Commodities, Markets, and Uses. 7th ed. Littleton, Colo.: Society for Mining, Metallurgy, and Exploration, 2006.
Manning, D. A. C. Introduction to Industrial Minerals. New York: Chapman & Hall, 1995.
Seelig, Mildred S., and Andrea Rosanoff. The Magnesium Factor. New York: Avery, 2003.
Silva, J. J. R. Fraústo da, and R. J. P. Williams. “The Biological Chemistry of Magnesium: Phosphate Metabolism.” In The Biological Chemistry of the Elements: The Inorganic Chemistry of Life. 2d ed. New York: Oxford University Press, 2001.
Natural Resources Canada. Canadian Minerals Yearbook, Mineral and Metal Commodity Reviews. http://www.nrcan-rncan.gc.ca/mms-smm/busi-indu/cmy-amc/com-eng.htm
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Magnesium (Chemical Elements)
Magnesium is the second element in Group 2 (IIA) of the periodic table a chart that shows how chemical elements are related to each other. The elements in Group 2 are known as the alkaline earth elements. Other elements in that group include beryllium, calcium, strontium, barium, and radium.
Compounds of magnesium have been used by humans for centuries. Yet, the element itself was not isolated until 1808. The long delay occurred because magnesium forms very stable compounds. That means that such compounds do not break down very easily.
Magnesium is the seventh most abundant element in the Earth's crust. It also occurs in large amounts dissolved in ocean waters.
Large amounts of magnesium are used to make alloys. An alloy is made by melting or mixing two or more metals. The mixture has properties different from those of the...
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Magnesium (Encyclopedia of Alternative Medicine)
Magnesium is an element (Mg) with an atomic weight of 24.312 and the atomic number 12. In its elemental form, magnesium is a light, silver-white metal. It is a cation, which means that its ion has a positive charge. Of the cations in the human body, magnesium is the fourth-most abundant. Ninety-nine percent of the body's magnesium is contained within its cells: about 60% in the bones, 20% in the muscles, 19%0% in the soft tissue, and 1% circulates in the blood. Important to both nutrition and medicine, magnesium, like calcium and phosphorus, is considered a major mineral. Magnesium in its carbonate and sulfate forms has been used for centuries as a laxative. The name of the element comes from Magnesia, a city in Greece where large deposits of magnesium carbonate were discovered in ancient times.
Magnesium is an important element in the body because it activates or is involved in many basic processes or functions, including:
- cofactor for over 300 enzymes
- oxidation of fatty acids
- activation of amino acids
- synthesis and breakdown of DNA
- immune function
- interactions with other nutrients, including potassium, vitamin B6, and boron...
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