Ferromanganese, a ferroalloy with high content of manganese, is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon, usually as coal and coke, in either a blast furnace or an electric arc furnace-type system, called a submerged arc furnace. The oxides undergo carbothermal reduction in the furnaces, producing the ferromanganese. Ferromanganese is used as a deoxidizer for steel.
Henry Bessemer invented the use of ferromanganese as a method of introducing manganese in controlled proportions during the production of steel. The advantage of combining powdered iron oxide and manganese oxide together is the lower melting point of the combined alloy compared to pure manganese oxide.
A North American standard specification is ASTM A99. The ten grades covered under this specification includes;
In 1872, Lambert von Pantz produced ferromanganese in a blast furnace, with significantly higher manganese content than was previously possible (37% instead of the previous 12%). This won his company international recognition, including a gold medal at the 1873 World Exposition in Vienna and a certificate of award at the 1876 Centennial Exposition in Pennsylvania.
Akhtenskite is a manganese oxide mineral with the chemical formula of MnO2 (or: ε-Mn4+O2) that was named after the Akhtensk deposit in Russia, where it was first discovered and noted in 1979. It can be found in the Akhtensk brown ironstone deposit, in the southern Ural Mountains, on Mt. Zarod, on the Sikhote-Alin Mountains, and in the Primorskiy Krai, all in Russia.Its crystals are usually hexagonal in shape, with flakiness and plating, usually because it replaced a mineral. Akhtenskite is a polymorphous with the much more widespread pyrolusite. It occurs in mixtures with "psilomelane" (recently renamed to romanechite) and with other manganese oxides in an iron oxide deposit, most likely bacterially altered from a previous mineral in the Akhtensk deposit. It also occurs in crusts of ferromanganese minerals on oceanic rocks. Its chemical makeup is 63% oxygen and 37% manganese.
Some minerals that are commonly associated with akhtenskite are: todorokite, pyrolusite, nsutite, goethite, and cryptomelane.Cupola furnace
A cupola or cupola furnace is a melting device used in foundries that can be used to melt cast iron, Ni-resist iron and some bronzes. The cupola can be made almost any practical size. The size of a cupola is expressed in diameters and can range from 1.5 to 13 feet (0.5 to 4.0 m). The overall shape is cylindrical and the equipment is arranged vertically, usually supported by four legs. The overall look is similar to a large smokestack.
The bottom of the cylinder is fitted with doors which swing down and out to 'drop bottom'. The top where gases escape can be open or fitted with a cap to prevent rain from entering the cupola. To control emissions a cupola may be fitted with a cap that is designed to pull the gases into a device to cool the gases and remove particulate matter.
The shell of the cupola, being usually made of steel, has refractory brick and plastic refractory patching material lining it. The bottom is lined in a similar manner but often a clay and sand mixture ("bod") may be used, as this lining is temporary. Finely divided coal ("sea coal") can be mixed with the clay lining so when heated the coal decomposes and the bod becomes slightly friable, easing the opening up of the tap holes. The bottom lining is compressed or 'rammed' against the bottom doors. Some cupolas are fitted with cooling jackets to keep the sides cool and with oxygen injection to make the coke fire burn hotter.Cutans
Cutans are the modification of the soil texture, or soil structure, at natural surfaces (particle, pore, or ped) in soil materials due to illuviation. Cutans are oriented deposits which can be composed of any of the component substances of the soil material. Cutans are common features in soil and represent focuses of chemical and biological reactions. Cutans may include clay skins or coatings of silica, sesquioxide, manganese, ferromanganese, soil organic matter or carbonate. Clay skins are also called argillans, and soil horizons with sufficient clay illuviation are termed argillic horizons.Defense National Stockpile Center
The Defense National Stockpile Center (DNSC) is a branch of the United States' Defense Logistics Agency, whose purpose it is to store, secure, and sell raw materials. The DNSC is based in Fort Belvoir and has operations throughout the United States. Materials they offer for sale include: aluminum oxide, beryllium, chromium, cobalt, diamonds, ferrochromium, ferromanganese, iodine, iridium, mica, niobium, platinum group metals, talc, tantalum, thorium, tin, tungsten and zinc.Ferro Alloys Corporation
The Ferro Alloys Corporation Limited (FACOR) was floated in 1955 by the house of Sarafs and Mors to become the first major producer of ferromanganese in India.
The year 1956, marked the beginning of the Ferro Alloys Corporation Limited at Sriramnagar, Garividi, Vizianagaram district, Andhra Pradesh. The founder was Seth Shriman Durgaprasadji Saraf (1911–1988). The registered office is at Tumsar, Bhandara district, Maharashtra.Ferroalloys are used as deoxidizers and alloy additives in the Steel manufacturing process.
The ferromanganese plant started production in 1957, equipped with three furnaces for production of high carbon ferromanganese and ferrosilicon. In 1969, a reduction furnace and a slag furnace were commissioned for the production of ferrochrome. The company independently, set up a 16 MVA furnace in 1981.
FACOR acquired a small steel plant at Nagpur in Maharashtra. In 1979, FACOR developed the technology to produce charge chrome in their own R&D wing. They have established a charge chrome plant at D.P.Nagar, Randia in Bhadrak district of Odisha in 1983. It is a 100% Export Oriented Project with a production capacity of 50,000 tons per annum. FACOR signed an agreement with Marc Rich and Co. AG Switzerland, as the sole selling agent of their entire charge chrome output for 10 years.The plants at Sriramnagar have facilities for raw material handling, metal, and slag casting, crushing, sizing and other ancillaries apart from furnaces for the smelting of ferroalloys. The raw materials are manganese ore, chromite and quartzite ores with principal elements of manganese, chromium and silicon respectively. They are obtained from the Andhra Pradesh, Odisha, Madhya Pradesh and Bihar states. The Ferro Alloys produced are High Carbon Ferro Chrome, Low Carbon Ferro Chrome, Silicochrome, Silicomanganese, and Magnesium Ferrosilicon, Ferromanganese etc., These alloys are tapped from electric arc furnaces in the molten state. They are prepared to the required size from 25 mm to 150 mm and transported to the various steel companies. The furnaces are connected to Two-stage venturi scrubber systems to maintain a clean environment in and around the production area.
FACOR has been accredited under ISO 9001:2000.The existing manpower at Sriramnagar is about 784 regular employees with 107 supervisory personnel, besides 1070 contract workmen.
In 2003, the charge chrome division along with the mining division in Odisha has been demerged as FACOR STEELS Ltd and the Ferro Alloys division at Garividi as FACOR ALLOYS Ltd.Ferroalloy
Ferroalloy refers to various alloys of iron with a high proportion of one or more other elements such as manganese (Mn), aluminium (Al), or silicon (Si). They are used in the production of steels and alloys. The alloys impart distinctive qualities to steel and cast iron or serve important functions during production and are, therefore, closely associated with the iron and steel industry, the leading consumer of ferroalloys. The leading producers of ferroalloys in 2014 were China, South Africa, India, Russia and Kazakhstan, which accounted for 84% of the world production. World production of ferroalloys was estimated as 52.8 million tonnes in 2015.Ferromanganese nodules
Ferromanganese nodules form in the oxidizing environment of the abyssal pelagic zone. They are the result of ion exchange reactions that precipitate ore components from the water (sedimentary) or out of the interstitial water of the sediments layers (diagenetic). The composition of Manganese-bearing minerals is dependent on how the nodules are formed; sedimentary nodules, which have a lower Mn2+ content than diagenetic, are dominated by Fe-vernadite, Mn-feroxyhyte, and asbolane-buserite while diagenetic nodules are dominated by buserite I, birnessite, todorokite, and asbolane-buserite.Geology of the British Indian Ocean Territory
The geology of the British Indian Ocean Territory comprises the Chagos Archipelago—the above water portion of the Chagos Bank. Formed from hotspot volcanism, the Chagos Bank was separated from the Nazareth Bank, which is administered by Mauritius, 36 million years ago by activity on the Central Indian Ridge. Aside from plate boundaries, the region is one of the most seismically active and earthquakes have caused subsidence of some islands.
Described by Charles Darwin as "a ledge of brecciated coral rocks projecting seawards from the outer shore," the Chagos Archipelago has unusual conglomerate platforms. The islands lack Eemian age carbonates, which are present in the Seychelles for reasons that are not clear—hypothesized to include local storm erosion.The offshore waters around the archipelago contain deep-sea ferromanganese nodules, with globular, dendritic and laminated microstructures formed from iron-manganese oxide.
Due to the US military presence on the island the US Geological Survey has conducted water resource analysis since 1984.
The islands of the Chagos Archipelago are mainly low and flat, mainly not reaching two meters above sea level.Horizon Guyot
Horizon Guyot is a presumably Cretaceous guyot (tablemount) in the Mid-Pacific Mountains, Pacific Ocean. It is an elongated ridge, over 300 kilometres (190 mi) long and 4.3 kilometres (2.7 mi) high, that stretches in a northeast-southwest direction and has two flat tops; it rises to a minimum depth of 1,443 metres (4,730 ft). The Mid-Pacific Mountains lie west of Hawaii and northeast of the Line Islands.
It was probably formed by a hotspot, but the evidence is conflicting. Volcanic activity occurred during the Turonian-Cenomanian eras 100.5–89.8 million years ago and another stage has been dated to have occurred 88–82 million years ago. Between these volcanic episodes, carbonate deposition from lagoonal and reefal environments set in and formed limestone. Volcanic islands developed on Horizon Guyot as well and were colonised by plants.
Horizon Guyot became a seamount during the Coniacian-Campanian period. Since then, pelagic ooze has accumulated on the seamount, forming a thick layer that is further modified by ocean currents and by various organisms that live on the seamount; sediments also underwent landsliding. Ferromanganese crusts were deposited on exposed rocks.Ioah Guyot
Ioah Guyot is a seamount in the Pacific Ocean, close to the Marshall Islands. Part of the Magellan Seamounts, it is a shield volcano that has erupted alkali basalt and hawaiite 87 million years ago, but may have continued erupting into the Miocene. During the Cretaceous, reefs developed on the guyot.Ita Mai Tai
Ita Mai Tai is a Cretaceous-early Cenozoic seamount northwest of the Marshall Islands and north of Micronesia. One among a number of seamounts in the Pacific Ocean, it is part of the Magellan Seamounts which may have a hotspot origin although Ita Mai Tai itself may not have formed on a hotspot.
The seamount is formed by volcanic rocks which form two adjacent volcanic centres that erupted between the Aptian-Albian and possibly as late as the Pliocene. Reef systems developed on the seamount after its formation and led to the deposition of limestones. Especially during the Oligocene the seamount subsided and lies now at 1,402 metres (4,600 ft) depth below sea level. Ferromanganese crusts as well as pelagic oozes were deposited on the submerged rocks.Lemkein
Lemkein is a seamount in the Western Pacific Ocean, west of Kwajalein.It is part of the Magellan Seamounts and is a volcanic seamount covered with sediments. Ferromanganese crusts occur in some places. Basalts in the form of pillow lavas altered to clay and zeoliths have been recovered from Lemkein.List of seamounts in the Marshall Islands
The Marshall Islands are the site of a number of seamounts. These volcanoes form several groups, including the Ralik Chain, the Ratak Chain and some seamounts around Anewetak. These seamounts are in turn part of a larger province that extends from the South Pacific to the Mariana Trench and is characterized by unusually shallow ocean ground.These seamounts and volcanoes do not have simple hotspot-like age progressions, with some volcanoes being younger than one would expect from age progression and having more than one active episode. In some places, a middle Cretaceous and a late Cretaceous episode of volcanic activity have been determined by radiometric dating. Despite this, some hotspot-based genesis models have been formulated, often implying that French Polynesian hotspots are responsible for the formation of seamounts, with the Society hotspot, Rurutu hotspot, Rarotonga hotspot and the Macdonald hotspot being candidate hotspots responsible for the development of the Marshall Islands seamounts. Such linkages are in part supported by geochemical data. Some discrepancies between the age and position of such seamounts and the predictions of the hotspot model may reflect the activity of short-lived hotspots linked to large mantle plumes that produce more than one hotspot.Lomilik
Lomilik is a seamount in the Western Pacific Ocean, within the exclusive economic zone of the Marshall Islands. It lies to the west of Anewetak atoll and is named after the best fishing site of Anewetak atoll.Lomilik has a 40-by-15-kilometre-wide (24.9 mi × 9.3 mi) summit terrace with the proper summit at circa 1,500 metres (4,900 ft) depth; a scarp separates the two and small hills reach depths of 1,350 metres (4,430 ft). The summit terrace is covered by rocks with ooze in between. A notch in the southern flank of Lomilik was probably created by a landslide. It is part of the Magellan Seamounts and consists of a Cretaceous volcano with a thin layer of carbonate rocks and ferromanganese. Lami seamount lies northwest of Lomilik.The rocks found on Lomilik consist of basalt and limestone. Fluorapatite, hyaloclastite, mudstone, phosphorite and siltstone have been identified in rocks from the seamount. Manganese nodules have been found on Lomilik and the manganese crusts on the seamount reach thicknesses of over 10 centimetres (3.9 in); the thickest crust recovered from an ocean is a 18 centimetres (7.1 in) thick ferromanganese crust from Lomilik recovered in 1989. The deposits on Lomilik could potentially be mined.Pako Guyot
Pako Guyot (also known as Caiwei or Pallada after the Russian frigate Pallada.) is a guyot in the Pacific Ocean, which reaches a depth of 1,210 metres (3,970 ft). It has dimensions of 40 by 65 kilometres (25 mi × 40 mi) and features a summit plateau 2,056 square kilometres (794 sq mi) wide with a shape corresponding to an irregular rectangle-triangle. It is part of the Magellan Seamounts. The seamount was volcanically active during the Cretaceous-Paleogene 91.3 million years ago and may have formed on a hotspot together with Ioah Guyot and Vlinder Guyot; a late phase of volcanism may have taken place in the Paleocene-Eocene.Volcanic rocks dredged from Pako are of sodium-potassium hawaiitic and trachybasaltic composition and geochemically resemble these erupted by the Rarotonga hotspot. Corals and squat lobsters have been found on the seamount. Ophiuroids, most of which are symbiotic with corals and sponges, live on the seamount and its flanks, and the seamount features substantial deposits of ferromanganese and phosphorite ores. In 2014, China obtained a contract with the International Seabed Authority allowing for exploration of Pako Guyot for cobalt crusts.Scorpius–Centaurus Association
The Scorpius–Centaurus Association (sometimes called Sco–Cen or Sco OB2) is the nearest
OB association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius,
Upper Centaurus–Lupus, and Lower Centaurus–Crux), whose mean distances range from
380 to 470 light years. Using improved Hipparcos data, Rizzuto and colleagues analysed nearby stars more closely, bringing the number of known members to 436. They doubt the need to add a subclassification because they found a more continuous spread of stars.The Sco–Cen subgroups range in age from 11 million years (Upper Scorpius) to roughly 15 million years (Upper Centaurus–Lupus and Lower Centaurus–Crux). Many of the bright stars in the constellations Scorpius, Lupus, Centaurus, and Crux are members of the Sco–Cen association, including Antares (the most massive member of Upper Scorpius), and most of the stars in the Southern Cross. Hundreds of stars have been identified as members of Sco-Cen, with masses ranging from roughly 15 solar masses (Antares) down to below the hydrogen-burning limit (i.e. brown dwarfs), and the total stellar population in each of the three subgroups is probably of the order 1000–2000.
The Sco–Cen OB association appears to be the most pronounced part of a large complex of recent (<20 million years) and ongoing star-formation. The complex contains several star-forming molecular clouds in Sco–Cen's immediate vicinity—the Rho Oph, Pipe Nebula, Barnard 68, Chamaeleon, Lupus, Corona Australis, and Coalsack cloud complexes (all at distances of ~120-200 parsecs), and several less populous, young stellar groups on the periphery of Sco–Cen, including the ~3–5 million-year-old epsilon Cha group, ~7 million-year-old eta Chamaeleontis cluster (also called Mamajek 1), ~8 million-year-old TW Hydrae association, ~12 million-year-old Beta Pictoris moving group, and possibly the ~30–50 million-year-old IC 2602 open cluster.The stellar members of the Sco–Cen association have convergent proper motions of approximately 0.02–0.04 arcseconds per year, indicative that the stars have nearly parallel velocity vectors, moving at about 20 km/s with respect to the Sun. The dispersion of the velocities within the subgroups are only of order 1–2 km/s, and the group is most likely gravitationally unbound. Several supernovae have exploded in Sco–Cen over the past 15 million years, leaving a network of expanding gas superbubbles around the group, including the Loop I Bubble.
To explain the presence of radioactive 60Fe in deep ocean ferromanganese crusts and in biogenic magnetite crystals within Pacific Ocean sediments it has been hypothesized that a nearby supernova, possibly a member of Sco–Cen, exploded in the Sun's vicinity roughly 3 million years ago, causing the Pliocene–Pleistocene boundary marine extinction. However, other findings cite the distance at which this supernova occurred at more than 100 parsec, maintaining that it is not likely not to have contributed to this extinction through the mechanism of what is known as the ultra-violet B (UV-B) catastrophe.
In 2019, researchers found interstellar iron in Antarctica which they relate to the Local Interstellar Cloud, which might have been formed near the Sco-Cen Association.Spiegeleisen
Spiegeleisen (literally "mirror-iron", German: Spiegel—mirror or specular; Eisen—iron) is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Spiegeleisen is sometimes also referred to as specular pig iron, Spiegel iron, just Spiegel, or Bisalloy.Tropic Seamount
Tropic Seamount is a Cretaceous seamount southwest of the Canary Islands and north of Cape Verde, one of a number of seamounts (a type of underwater volcanic mountain) in this part of the Atlantic Ocean. It was probably formed by volcanic processes triggered by the proximity to the African continent. Tropic Seamount is located at a depth of 970 metres (3,180 ft) and has a summit platform with an area of 120 square kilometres (46 sq mi).
Tropic Seamount is formed by volcanic rocks including basalt and trachyte and was probably an island at first; for reasons unknown it sunk to its present day depth. Large landslides and late volcanic activity affected the seamount, cutting large scars into its flanks and forming cones on its summit plateau, respectively. Volcanic activity at Tropic Seamount commenced almost 120 million years ago and ended about 60 million years ago. Later, sedimentation commenced on the seamount leading to the deposition of manganese crusts and pelagic sediments; iron and manganese accumulated in crusts over time beginning a few tens of millions of years ago.Zealandia
Zealandia (), also known as the New Zealand continent or Tasmantis, is an almost entirely submerged mass of continental crust that sank after breaking away from Australia 60–85 million years ago, having separated from Antarctica between 85 and 130 million years ago. It has variously been described as a continental fragment, a microcontinent, a submerged continent, and a continent. The name and concept for Zealandia was proposed by Bruce Luyendyk in 1995. Zealandia's status as a continent is not universally accepted, but New Zealand geologist Nick Mortimer has commented that "if it wasn't for the ocean" it would have been recognized as such long ago.The land mass may have been completely submerged about 23 million years ago, and most of it (93%) remains submerged beneath the Pacific Ocean. With a total area of approximately 4,920,000 km2 (1,900,000 sq mi), it is the world's largest current microcontinent, more than twice the size of the next-largest microcontinent and more than half the size of the Australian continent. As such, and due to other geological considerations, such as crustal thickness and density, it is arguably a continent in its own right. This was the argument which made news in 2017, when geologists from New Zealand, New Caledonia, and Australia concluded that Zealandia fulfills all the requirements to be considered a continent, rather than a microcontinent or continental fragment.Zealandia supports substantial inshore fisheries and contains gas fields, of which the largest known is New Zealand's Maui gas field, near Taranaki. Permits for oil exploration in the Great South Basin were issued in 2007. Offshore mineral resources include iron sands, volcanic massive sulfides and ferromanganese nodule deposits.