Where Found (Encyclopedia of Global Resources)
Manganese oxides are abundant in nature; however, large, high-grade deposits are relatively rare. Concentrations of the element approximately 250 to 500 times greater than the average crustal abundance are required to produce ore. All the major ore deposits are sedimentary in origin and consist of various manganese oxide minerals. The major deposits of the world are sedimentary in origin and are located in Russia, Africa, and Brazil. The five leading manganese-producing countries in 2007 were South Africa, Australia, China, Gabon, and Brazil. Together these countries account for 70 percent of the world’s total output.
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Primary Uses (Encyclopedia of Global Resources)
Technical Definition (Encyclopedia of Global Resources)
Manganese (atomic number 25, chemical symbol Mn) is the twelfth most abundant element in the crust of the Earth and makes up about 0.1 percent of the crust by weight. In its pure state, which does not occur in nature, it is a hard, brittle metal with a gray color, a melting point of 1,260° Celsius, a boiling point of 1,900° Celsius, and a density of 7.2 grams per cubic centimeter. It resembles iron in many of its properties and has oxidation states of +2, +3, +4, +6, and +7. As is true of iron, the reduced +2 form is quite soluble under near-surface conditions and is carried in solution by stream and groundwater.
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Description, Distribution, and Forms (Encyclopedia of Global Resources)
Because of its great crustal abundance, small amounts of manganese, in the form of dark-colored oxide minerals, are common in most rocks. For commercial production, however, ore bodies averaging at least 35 percent manganese and containing millions of metric tons of the metal are required. The highest-grade ore contains more than 48 percent manganese. Such deposits are not common. All the known major deposits are of sedimentary origin. There are several ore minerals of manganese, but the most important are all oxides: pyrolusite (MnO2), psilomelane (Mn2O3 2H2O), and manganite (Mn2O3 H2O).
Although manganese occurs in several oxidation states, the reduced +2 is most common in subsurface waters because of its solubility. Manganese oxide minerals precipitate readily at a boundary between oxidizing and reducing conditions, such as the reducing groundwater percolating into well-oxygenated stream water. As a result, manganese oxide coatings on stream pebbles and rocks are common, so common that they usually go unnoticed. Similar black coatings are also common in arid regions in the form of “desert varnish” and in deep freshwater lakes. In the ocean, large manganese oxide nodules occur. Changes from reducing to oxidizing conditions have been implicated as important in producing all of these common surface forms of manganese oxide, but it is also likely that manganese-oxidizing bacteria play an important...
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History (Encyclopedia of Global Resources)
Manganese oxide has been known since antiquity, when it was used in glass manufacture, but the metal itself was not isolated until 1770. There was little interest in the metal until 1856, when it was discovered that manganese could be used to remove sulfur and oxygen impurities as a slag from molten steel. All steel up to this time had been extremely brittle because of the presence of these impurities. An important world market for manganese quickly developed. The world’s major deposit of manganese was discovered in the Nikopol’ Basin in Ukraine in the 1920’s. Subsequently, this area became the world’s major producer. In the nineteenth century, the United States was self-sufficient in manganese, but these deposits are all exhausted.
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Obtaining Manganese (Encyclopedia of Global Resources)
Two types of sedimentary deposits account for most of the world’s production. The first type, illustrated by the world’s largest deposit at Nikopol’ in southern Ukraine, consists of manganese in the form of earthy masses and nodules of manganese oxide in beds of sandy clay and limestone. This type of deposit is thought to have originated by a two-step process. First, manganese in its reduced form, derived from the weathering and erosion of continental areas, is carried by streams in solution to the open sea. Second, in the sea, reduced manganese undergoes oxidation, causing it to precipitate as manganese oxide minerals because of the strongly oxidizing conditions in the open ocean.
The second important type of deposit has resulted from the weathering of rocks containing small amounts of manganese silicate and carbonate minerals. These minerals are resistant to weathering, so their relative abundance increases as the less resistant minerals are dissolved. Eventually, a large, high-grade deposit of manganese may be produced. Geologists use the term “residual” to refer to any type of mineral deposit in which the valuable material has been concentrated by weathering. Important manganese deposits of this type occur in Brazil and China.
Mining companies became interested in deep-sea manganese nodules in the 1960’s and 1970’s. The richest area seems to be a portion of the deep Pacific floor extending 4,800...
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Uses of Manganese (Encyclopedia of Global Resources)
Most manganese is used during the manufacture of steel to remove sulfur and oxygen. There are no practical replacements for manganese in this essential role. Approximately 90 percent of the manganese that is consumed each year in the United States is used in the manufacture of steel. Manganese is also used as a component in certain aluminum alloys and in dry cell batteries. Minor amounts are used as a colorant in glass, in fertilizers, and as a gasoline additive.
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Further Reading (Encyclopedia of Global Resources)
Adriano, Domy C. “Manganese.” In Trace Elements in Terrestrial Environments: Biogeochemistry, Bioavailability, and Risks of Metals. 2d ed. New York: Springer, 2001.
Greenwood, N. N., and A. Earnshaw. “Manganese, Technetium, and Rhenium.” In Chemistry of the Elements. 2d ed. Boston: Butterworth-Heinemann, 1997.
Howe, P. D., H. H. Malcolm, and S. Dobson. Manganese and Its Compounds: Environmental Aspects. Geneva, Switzerland: World Health Organization, 2004.
Klimis-Tavantzis, Dorothy J., ed. Manganese in Health and Disease. Boca Raton, Fla.: CRC Press, 1994.
Kogel, Jessica Elzea, et al., eds. “Manganese.” In Industrial Minerals and Rocks: Commodities, Markets, and Uses. 7th ed. Littleton, Colo.: Society for Mining, Metallurgy, and Exploration, 2006.
Priest, Tyler. Global Gambits: Big Steel and the U.S. Quest for Manganese. Westport, Conn.: Praeger, 2003.
Sigel, Astrid, and Helmut Sigel, eds. Manganese and Its Role in Biological Processes. New York: Marcel Dekker, 2000.
Wolf, Karl H., ed. Handbook of Strata-Bound and Stratiform Ore Deposits. Vol. 2. New York: Elsevier Scientific, 1986.
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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Manganese (Chemical Elements)
Manganese is a transition metal. The transition metals are the large block of elements in the middle of the periodic table. The periodic table is a chart that shows how chemical elements are related to each other. The transition metals make up Rows 4 through 7 in Groups 3 through 12 of the periodic table. Many of the best known and most widely used metals are in this group of elements.
It took chemists some time to discover the difference between manganese and iron. The two metals have very similar properties and often occur together in the Earth's crust. The first person to clearly identify the differences between the two elements was Swedish mineralogist Johann Gottlieb Gahn (1745-1818) in 1774.
Manganese plays an interesting role in the U.S. economy. It is absolutely essential in the production of iron and steel. No element has been found that can...
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Manganese (Encyclopedia of Alternative Medicine)
Not to be confused with magnesium, manganese is a trace mineral used by some people to help prevent bone loss and alleviate the bothersome symptoms associated with premenstrual syndrome (PMS). It may have a number of other beneficial effects as well. While most of the body's mineral content is composed of such macrominerals as calcium, magnesium, and potassium, certain trace minerals are also considered essential in very tiny amounts to maintain health and ensure proper functioning of the body. They usually act as coenzymes, working as a team with proteins to facilitate important chemical reactions. Even without taking manganese supplements, people with an average diet consume somewhere between 2 and 3 mg of the mineral through food and drink. While most authorities agree that manganese is a vital micronutrient, it is not known for certain if taking extra amounts can be helpful in treating osteoporosis, menstrual symptoms, or other problems.
Manganese, which is concentrated mainly in the liver, skeleton, pancreas, and brain, is considered important because it is used to make several key enzymes in the body and activates others. For example, one of the enzymes made from manganese is called superoxide dismutase (SOD), an antioxidant facilitator. Antioxidants help to protect cells from damage caused by free radicals,...
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