Misplaced Pages

#924075

91-449: The mine is about 22 miles (35 km) from the port of Bône in the Mokta hill beside at the foot of a mountain chain that runs from south to north, then turns east to Bône. The name "Mokta-el-Hadid" (the iron pass) indicates that the presence of iron has long been known, but there is no sign that it was worked before the first small-scale attempts in 1840. The geologist Henri Fournel discovered

182-591: A Mohs hardness of 5–6 and leaves a black streak . Small grains of magnetite are very common in igneous and metamorphic rocks . The chemical IUPAC name is iron(II,III) oxide and the common chemical name is ferrous-ferric oxide . In addition to igneous rocks, magnetite also occurs in sedimentary rocks , including banded iron formations and in lake and marine sediments as both detrital grains and as magnetofossils . Magnetite nanoparticles are also thought to form in soils, where they probably oxidize rapidly to maghemite . The chemical composition of magnetite

273-609: A face-centered cubic lattice and iron cations occupying interstitial sites . Half of the Fe cations occupy tetrahedral sites while the other half, along with Fe cations, occupy octahedral sites. The unit cell consists of thirty-two   O ions and unit cell length is a = 0.839 nm. As a member of the inverse spinel group, magnetite can form solid solutions with similarly structured minerals, including ulvospinel ( Fe 2 TiO 4 ) and magnesioferrite ( MgFe 2 O 4 ). Titanomagnetite, also known as titaniferous magnetite,

364-566: A compass in Tasmania to keep navigation problems to the minimum. Magnetite crystals with a cubic habit are rare but have been found at Balmat, St. Lawrence County, New York , and at Långban, Sweden . This habit may be a result of crystallization in the presence of cations such as zinc. Magnetite can also be found in fossils due to biomineralization and are referred to as magnetofossils . There are also instances of magnetite with origins in space coming from meteorites . Biomagnetism

455-458: A component of protein plaques in the brain. Such plaques have been linked to Alzheimer's disease . Increased iron levels, specifically magnetic iron, have been found in portions of the brain in Alzheimer's patients. Monitoring changes in iron concentrations may make it possible to detect the loss of neurons and the development of neurodegenerative diseases prior to the onset of symptoms due to

546-528: A crystal structure phase transition from a monoclinic structure to a cubic structure known as the Verwey transition . Optical studies show that this metal to insulator transition is sharp and occurs around 120   K. The Verwey transition is dependent on grain size, domain state, pressure, and the iron-oxygen stoichiometry . An isotropic point also occurs near the Verwey transition around 130   K, at which point

637-430: A highly porous high-surface-area material, which enhances its effectiveness as a catalyst. Magnetite micro- and nanoparticles are used in a variety of applications, from biomedical to environmental. One use is in water purification: in high gradient magnetic separation, magnetite nanoparticles introduced into contaminated water will bind to the suspended particles (solids, bacteria, or plankton, for example) and settle to

728-431: A human health hazard, airborne magnetite is a result of pollution (specifically combustion). These nanoparticles can travel to the brain via the olfactory nerve, increasing the concentration of magnetite in the brain. In some brain samples, the nanoparticle pollution outnumbers the natural particles by as much as 100:1, and such pollution-borne magnetite particles may be linked to abnormal neural deterioration. In one study,

819-455: A licence from Siemens and first applied his regenerative furnace for making steel . Their process was known as the Siemens–Martin process or Martin–Siemens process , and the furnace as an "open-hearth" furnace. Most open hearth furnaces were closed by the early 1990s, not least because of their slow operation, being replaced by the basic oxygen furnace or electric arc furnace . Whereas

910-430: A mass of pure oxidized iron, with no admixture of rock. To the east of this deposit, which few deposits known elsewhere could parallel, the oxidized iron pierces several other points." Talabot asked the geologist Émilien Dumas to assess the deposit. He contacted the polytechnician and engineer of mines Alphonse Parran to form the new company and start exploitation. Due to shortage of both labour and capital, little progress

1001-679: A merger with the steelworks at Alais in the Gard were drawn up, possibly part of a larger merger with the mines of the Grand-Combe, but stalled. In 1863 the Société de Mokta el Hadid was established definitively. It took over the operation of the Société Civile des Mines et Hauts Fourneaux des Karezas mentioned above. Plans were drawn up to combine the Mokta el Hadid mines with the Firminy , Loire, steelworks,

SECTION 10

#1733092791925

1092-404: A permanent magnet itself. With the exception of extremely rare native iron deposits, it is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces of magnetite, called lodestone , will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism. Magnetite is black or brownish-black with a metallic luster, has

1183-464: A process called teeming , or it may be used in continuous casting in the rolling mill. The regenerators are the distinctive feature of the furnace and consist of fire-brick flues filled with bricks set on edge and arranged in such a way as to have a great number of small passages between them. The bricks absorb most of the heat from the outgoing waste gases and return it later to the incoming cold gases for combustion. Carl Wilhelm Siemens developed

1274-499: A science important in understanding plate tectonics and as historic data for magnetohydrodynamics and other scientific fields . The relationships between magnetite and other iron oxide minerals such as ilmenite , hematite, and ulvospinel have been much studied; the reactions between these minerals and oxygen influence how and when magnetite preserves a record of the Earth's magnetic field . At low temperatures, magnetite undergoes

1365-558: A trip to the mine and the city of Bône. A photograph survives of the emperor and his entourage taking refreshment under a tent at the mine site. Paulin Talabot founded the Société Générale Algérienne (SGA) in 1865 to promote economic growth in the colony of Algeria, which created five villages for French colonists. It was granted 100,000 hectares (250,000 acres) of land in exchange for a 100 million franc loan to Napoleon III, which

1456-665: A uranium mining concession in Niger to be capitalized 45% by the Atomic Energy Commission, 40% by the private French companies Mokta El Hadid and French Uranium-ore, and 15% by the state of Niger. The exploitation company was Somaïr. Also in 1967 the merger activity between Suez and the Banque de l'Union parisienne caused Suez to become a direct shareholder in Mokta, and also in Huaron and Comuf. In 1968 Mokta joined forces with Pechiney to form

1547-525: A vast deposit of magnetite-bearing sand dunes in Peru . The dune field covers 250 square kilometers (100 sq mi), with the highest dune at over 2,000 meters (6,560 ft) above the desert floor. The sand contains 10% magnetite. In large enough quantities magnetite can affect compass navigation . In Tasmania there are many areas with highly magnetized rocks that can greatly influence compasses. Extra steps and repeated observations are required when using

1638-416: Is Fe (Fe ) 2 (O ) 4 . This indicates that magnetite contains both ferrous ( divalent ) and ferric ( trivalent ) iron, suggesting crystallization in an environment containing intermediate levels of oxygen. The main details of its structure were established in 1915. It was one of the first crystal structures to be obtained using X-ray diffraction . The structure is inverse spinel , with O ions forming

1729-425: Is a batch process and a batch is called a "heat". The furnace is first inspected for possible damage. Once it is ready or repaired, it is charged with light scrap, such as sheet metal, shredded vehicles or waste metal. The furnace is heated using burning gas. Once the charge has melted, heavy scrap, such as building, construction or steel milling scrap is added, together with pig iron from blast furnaces . Once all

1820-517: Is a solid solution between magnetite and ulvospinel that crystallizes in many mafic igneous rocks. Titanomagnetite may undergo oxy-exsolution during cooling, resulting in ingrowths of magnetite and ilmenite. Natural and synthetic magnetite occurs most commonly as octahedral crystals bounded by {111} planes and as rhombic-dodecahedra . Twinning occurs on the {111} plane. Hydrothermal synthesis usually produces single octahedral crystals which can be as large as 10 mm (0.39 in) across. In

1911-703: Is also a chemical basis for cellular sensitivity to electric and magnetic fields ( galvanotaxis ). Pure magnetite particles are biomineralized in magnetosomes , which are produced by several species of magnetotactic bacteria . Magnetosomes consist of long chains of oriented magnetite particle that are used by bacteria for navigation. After the death of these bacteria, the magnetite particles in magnetosomes may be preserved in sediments as magnetofossils. Some types of anaerobic bacteria that are not magnetotactic can also create magnetite in oxygen free sediments by reducing amorphic ferric oxide to magnetite. Several species of birds are known to incorporate magnetite crystals in

SECTION 20

#1733092791925

2002-444: Is any of several kinds of industrial furnace in which excess carbon and other impurities are burnt out of pig iron to produce steel . Because steel is difficult to manufacture owing to its high melting point , normal fuels and furnaces were insufficient for mass production of steel, and the open-hearth type of furnace was one of several technologies developed in the nineteenth century to overcome this difficulty. Compared with

2093-445: Is beside the Lake of Fetzara . When it started operation the lake's surface elevation would have reached 16 metres (52 ft) in winter, with an area of 14,000 hectares (35,000 acres). The lake was bordered with reeds and rushes, used for nesting by migratory birds, and was rich in fish. The lake was considered a source of fever, and a 16 kilometres (9.9 mi) drainage channel flowing into

2184-426: Is burnt (oxidized) to give magnetite or wüstite of a defined particle size. The magnetite (or wüstite) particles are then partially reduced, removing some of the oxygen in the process. The resulting catalyst particles consist of a core of magnetite, encased in a shell of wüstite, which in turn is surrounded by an outer shell of iron metal. The catalyst maintains most of its bulk volume during the reduction, resulting in

2275-452: Is flushed away in the fumes, while steel is formed. To increase the oxidizing power of the "heat", more iron oxide ore can be added. The process is far slower than that of the Bessemer converter and thus easier to control and sample for quality assessment. Preparing a heat usually takes eight to eight and a half hours, and longer to finish the conversion into steel. As the process is slow, it

2366-471: Is not necessary to burn all the carbon away as in the Bessemer process, but the process can be terminated at any given point when the desired carbon content has been achieved. The furnace is tapped in the same way a blast furnace is tapped; a hole is drilled in the side of the hearth and the raw steel flows out. Once all the steel has been tapped, the slag is skimmed away. The raw steel may be cast into ingots,

2457-595: Is sometimes found in large quantities in beach sand. Such black sands (mineral sands or iron sands ) are found in various places, such as Lung Kwu Tan in Hong Kong; California , United States; and the west coast of the North Island of New Zealand. The magnetite, eroded from rocks, is carried to the beach by rivers and concentrated by wave action and currents. Huge deposits have been found in banded iron formations. These sedimentary rocks have been used to infer changes in

2548-453: Is still not well understood, and there has been a general lag in applying more modern, interdisciplinary techniques to the study of biomagnetism. Electron microscope scans of human brain-tissue samples are able to differentiate between magnetite produced by the body's own cells and magnetite absorbed from airborne pollution, the natural forms being jagged and crystalline, while magnetite pollution occurs as rounded nanoparticles . Potentially

2639-452: Is usually related to the presence of biogenic crystals of magnetite, which occur widely in organisms. These organisms range from magnetotactic bacteria (e.g., Magnetospirillum magnetotacticum ) to animals, including humans, where magnetite crystals (and other magnetically sensitive compounds) are found in different organs, depending on the species. Biomagnetites account for the effects of weak magnetic fields on biological systems. There

2730-489: The Bessemer process , which it displaced, its main advantages were that it did not expose the steel to excessive nitrogen (which would cause the steel to become brittle ), was easier to control, and permitted the melting and refining of large amounts of scrap iron and steel . The open-hearth furnace was first developed by German -born engineer Carl Wilhelm Siemens . In 1865, the French engineer Pierre-Émile Martin took out

2821-657: The Gafsa phosphate deposits in Tunisia in 1886. In Tunisia as of 1893 the company owned concessions at Ras Radjid, Bou lanague, Dj Bellif and Ganara in the Kroumine between Tabarka and Cap Serrat . The ores, which had not yet been worked, were brown and red hematites with an average of 50% iron. By 1895 the company had bought all the iron ore beds in the Ouelhasses Cheragas ore district of Algeria apart from Boukourdan. These included

Société Mokta El Hadid - Misplaced Pages Continue

2912-473: The Gard coal mines and the Saut-du-Tarn steelworks near Albi , Tarn. 20 million francs of capital would be needed, including 8 million of fresh capital for upgrades at the various sites. These plans also dragged out. Extensive construction was undertaken at Bône in 1856–69 to build an 80 hectares (200 acres) sheltered port facility to handle the ore from Mokta el Hadid. In 1862 the existing railway line from

3003-659: The Oued Meboudja was proposed, but although the SGA had rights to the northern and eastern shores of the lake it did nothing. In the 1870s the company planted many eucalyptus trees around the Lake of Fetzara. A report published in 1901 said, "The example of Lake Fetzara has been much quoted; its marshy miasma infected the large mining works of Mokta-el-Hadid, decimated the staff, and rendered existence in this locality insupportable. Now, thanks to well developed forests of Eucalyptus, it presents all

3094-464: The Siemens regenerative furnace in the 1850s, and claimed in 1857 to be recovering enough heat to save 70–80% of the fuel. This furnace operates at a high temperature by using regenerative preheating of fuel and air for combustion . In regenerative preheating, the exhaust gases from the furnace are pumped into a chamber containing bricks, where heat is transferred from the gases to the bricks. The flow of

3185-466: The separation of coal from waste , dense medium baths were used. This technique employed the difference in densities between coal (1.3–1.4 tonnes per m ) and shales (2.2–2.4 tonnes per m ). In a medium with intermediate density (water with magnetite), stones sank and coal floated. Magnetene is a two-dimensional flat sheet of magnetite noted for its ultra-low-friction properties. Martin process An open-hearth furnace or open hearth furnace

3276-402: The 1940s. From 1901 the company began using Moroccan workers in its Béni Saf mines. The Compagnie des mines du Djebel-Djerissa was created in 1899 with a capital of 4.5 million francs divided into 9,000 shares of 500 francs. In 1905 the nominal share value was reduced to 400 francs and the capital was reduced to 3.6 million francs. The Société du Djebel-Djerissa became in effect a subsidiary of

3367-488: The Bureau of Mines of Overseas France (21%), Eastern Tjbangi Mining Company (15%), Mokta el Hadid group (15%) and the U.S. Steel (49%). A 220 miles (350 km) railway had first to be built to the coast, so full production was not expected until at least 1960. The Compagnie minière de l'Ogooué (Comilog) had initial capital of CFA 150 million. The first ore was shipped from Moanda on 2 October 1962. In 1957, Georges Perrineau

3458-493: The Compagnie française de Mokta was a wholly owned subsidiary of COGEMA (Compagnie générale des matières nucléaires), a French company involved in mining and processing uranium. Magnetite Magnetite is a mineral and one of the main iron ores , with the chemical formula Fe Fe 3+ 2 O 4 . It is one of the oxides of iron , and is ferrimagnetic ; it is attracted to a magnet and can be magnetized to become

3549-580: The Das rih and Bar el Baroud beds of Béni Saf, and the Ten Kreut, Djed el Haouraia and Sidi-safi groups of ore beds. Only the Bar el Baroud was being worked, using open-cut mining to extract ore with at least 55% iron. The port of Béni Saf was operated privately by the company, which had built it and had a 99-year lease. Estimated output was 291,547 metric tons in 1892 and 203,338 tons in 1893. Destinations, in order, were England,

3640-528: The Mokta deposits started showing signs of running out Alphonse Parran obtained the deposit of Rar El Baroud near Béni Saf in 1879. The ore in the Béni Saf region near Montagnac (now named Remchi ) is hematite with 2% manganese. Between 1867 and 1947 the region produced 30 million metric tons of ore. Alphonse Parran was also involved in one of the first iron ore mines in Kryvbas (then Russia, now Ukraine) in 1881 and

3731-483: The Mokta el Hadid mine was found, and the Talabots gained the concession. The ore was in a vein 2,500 metres (8,200 ft) long and 10 to 50 metres (33 to 164 ft) wide. The magnetite ore was 70% pure iron. This ore, free of sulfur and phosphorus, was much more suitable for the Bessemer and Martin processes than the poorer ores high in phosphorus that are typical of France, Belgium, Luxembourg and Germany. Plans for

Société Mokta El Hadid - Misplaced Pages Continue

3822-590: The Mokta-el-Hadid mine. In 1874 the Mokta el Hadid mine alone shipped 430,000 tons of ore, containing 260,000 tons of iron. At this time Britain was producing a total of 500,000 tons of steel. The mine was said to be capable of supporting 25% of Europe's steel production. In 1875–76 the Bou Djima River, which was carrying silt into the port, was diverted to the Seybouse River . The railway could now be extended to

3913-654: The Netherlands, France, the US and Belgium. The company obtained the Boukhadra deposits near the Tunisian border in 1902. In the period from 1900 to 1930 the company was among the powerful capitalist groups in the French colonial empire that provided exceptional rates of profit. Alphonse Parran was succeeded as head of the company in 1900 by Édouard de Billy (1866–1919). Billy was replaced in 1918 by Charles-Émile Heurteau (1878–1961), who took

4004-636: The Péchiney Mokta mining company, which would manage various uranium operations and fund research activity, particularly in Saskatchewan , Canada. In October 1970 the Société le Nickel, soon after to become the Imetal holding company, took over the Mokta company through a share swap. Perrineau remained a director and advisor. In 1980 Imetal absorbed Mokta, which was renamed Compagnie française de Mokta (CFM). As of 1991

4095-521: The QFM buffer. At still lower oxygen levels, magnetite forms a buffer with wüstite known as the MW buffer. The QFM and MW buffers have been used extensively in laboratory experiments on rock chemistry. The QFM buffer, in particular, produces an oxygen fugacity close to that of most igneous rocks. Commonly, igneous rocks contain solid solutions of both titanomagnetite and hemoilmenite or titanohematite. Compositions of

4186-505: The Siemens regenerative furnace is the rapid production of large quantities of basic steel, used for example to construct high-rise buildings. The usual size of furnaces is 50 to 100 tons, but for some special processes they may have a capacity of 250 or even 500 tons. The Siemens–Martin process complemented rather than replaced the Bessemer process . It is slower and thus easier to control, allowing production of better product. It also permits

4277-642: The Société Mokta El Hadid of Algeria, which took a stake of 5,200 shares in the mine in 1906. In 1905 the small Mokta railway was connected to the departmental network, connecting the port of Bone to the Jemmapes ( Azzaba ) region, and now extended as far as Saint-Charles ( Ramdane Djamel ). Philippe de Cerner, the company manager in Bône, had convinced the government to extend the railway west from Ain Mokra to connect with

4368-411: The Talabots or their associates had obtained three of the four concessions in the Bône region. Algeria in the 19th century did not have coking coal, so did not process its iron ore. Instead, the ore was shipped to the coast and sold to a shipper, who in turn sold it to European steel mills for about twice the price. Talabot thought of building an ironworks at Bône, but abandoned the idea in 1848 part due to

4459-460: The bottom of the fluid, allowing the contaminants to be removed and the magnetite particles to be recycled and reused. This method works with radioactive and carcinogenic particles as well, making it an important cleanup tool in the case of heavy metals introduced into water systems. Another application of magnetic nanoparticles is in the creation of ferrofluids . These are used in several ways. Ferrofluids can be used for targeted drug delivery in

4550-410: The brain – magnetite, hemoglobin (blood) and ferritin (protein), and areas of the brain related to motor function generally contain more iron. Magnetite can be found in the hippocampus . The hippocampus is associated with information processing, specifically learning and memory. However, magnetite can have toxic effects due to its charge or magnetic nature and its involvement in oxidative stress or

4641-531: The center of the lake, crossed the 22 metres (72 ft) western flank and led to the Meboudja. The surface elevation had dropped to 12 metres (39 ft) by 1880, but the lake remained swampy in summer. After 1903 the company ceded its rights to the Lake of Fetzara to the SGA colony, which took over the work and completed it in 1935. As of 1878 the company had also opened the Kareza, Bou H'amra and Marouania mines. Before

SECTION 50

#1733092791925

4732-559: The characteristic nanoparticles were found in the brains of 37 people: 29 of these, aged 3 to 85, had lived and died in Mexico City, a significant air pollution hotspot. Some of the further eight, aged 62 to 92, from Manchester, England, had died with varying severities of neurodegenerative diseases. Such particles could conceivably contribute to diseases like Alzheimer's disease . Though a causal link has not yet been established, laboratory studies suggest that iron oxides such as magnetite are

4823-471: The conditions of a tolerable hygiene." The report then noted that the improvement could also be attributed in part to better medical attention and the fact that most of the staff commuted to work from Bône. The trees were all killed by salt water seeping from the lake. In 1877 the Mokta El Hadid company gained permission to drain the lake in exchange for free transfer of the reclaimed land. A channel led from

4914-588: The danger of attack by the Algerians and in part to a threatened boycott of Algerian iron ore by the Schneiders of Le Creusot . A report by Fournel to the Académie des sciences on 14 May 1848 said, "to the north of Lake F'Zara there is a whole mountain, the Mokta-el-Hadid (the quarry of iron) which emerges from the gneisses and literally presents from foot to top, that is to say over a height of more than one hundred meters,

5005-529: The deposits of magnetite in 1843. The businessman Paulin Talabot had a "Mediterranean dream" involving "the exploitation of the mines of the Bône region, which would feed his coal mines in the Grand-Combe by means of rapid transport in his ships of the Compagnie Générale Transatlantique , relayed by his Algerian railroad cars and those of the PLM ." Before Fournel's survey was complete, in 1845

5096-697: The earliest example of open-hearth steelmaking is found about 2000 years ago in the culture of the Haya people , in present day Tanzania , and in Europe in the Catalan forge , invented in Spain in the 8th century, it is usual to confine the term to certain 19th-century and later steelmaking processes, thus excluding bloomeries (including the Catalan forge), finery forges , and puddling furnaces from its application. The open-hearth process

5187-429: The furnace is then reversed so that fuel and air pass through the chamber and are heated by the bricks. Through this method, an open-hearth furnace can reach temperatures high enough to melt steel, but Siemens did not initially use it for that. In 1865, the French engineer Pierre-Émile Martin took out a license from Siemens and first applied his regenerative furnace for making steel. The most appealing characteristic of

5278-468: The government that required the company to build blast furnaces in Bône and to pay higher royalties to Algeria. The agreement and specifications for this project were signed early in 1918, with 85% of the capital supplied by Mokta and Hauts Fourneaux de Rouen, and 15% by Denain-Anzin and a consortium of Algerian banks. Two blast furnaces would be built with combined annual capacity of 80,000 tons. However, after Charles Jonnart returned to Algeria as governor

5369-402: The human body. The magnetization of the particles bound with drug molecules allows "magnetic dragging" of the solution to the desired area of the body. This would allow the treatment of only a small area of the body, rather than the body as a whole, and could be highly useful in cancer treatment, among other things. Ferrofluids are also used in magnetic resonance imaging (MRI) technology. For

5460-496: The magnetic fields the organism was exposed to, potentially allowing scientists to learn about the migration of the organism or about changes in the Earth's magnetic field over time. Living organisms can produce magnetite. In humans, magnetite can be found in various parts of the brain including the frontal , parietal , occipital , and temporal lobes , brainstem , cerebellum and basal ganglia . Iron can be found in three forms in

5551-454: The magnetite with needle-shaped particles of gamma ferric oxide (γ-Fe 2 O 3 ). Approximately 2–3% of the world's energy budget is allocated to the Haber Process for nitrogen fixation, which relies on magnetite-derived catalysts. The industrial catalyst is obtained from finely ground iron powder, which is usually obtained by reduction of high-purity magnetite. The pulverized iron metal

SECTION 60

#1733092791925

5642-415: The main line to Philippeville ( Skikda ), and then persuaded the government to assume responsibility for running the line in the public interest. Philippe de Cerner was appointed director of the new line from 1908 until his retirement in 1917. In 1912 the Compagnie des minerais de fer magnétique de Mokta-el-Hadid had a capital of 20 million and made a profit of 4.5 million. When World War I began Mokta-el Hadid

5733-492: The melting and refining of large amounts of scrap steel, further lowering steel production costs and recycling an otherwise troublesome waste material. One of its important drawbacks is that melting and refining a charge takes several hours. This was an advantage in the early 20th century, as it gave plant chemists time to analyze the steel and decide how much longer to refine it. But by about 1975, electronic instruments such as atomic absorption spectrophotometers had made analysis of

5824-418: The mineral pairs are used to calculate oxygen fugacity: a range of oxidizing conditions are found in magmas and the oxidation state helps to determine how the magmas might evolve by fractional crystallization . Magnetite also is produced from peridotites and dunites by serpentinization . Lodestones were used as an early form of magnetic compass . Magnetite has been a critical tool in paleomagnetism ,

5915-533: The mineral. In the municipalities of Molinaseca, Albares, and Rabanal del Camino, in the province of León (Spain), there is a magnetite deposit in Ordovician terrain, considered one of the largest in Europe. It was exploited between 1955 and 1982. Deposits are also found in Norway , Romania , and Ukraine . Magnetite-rich sand dunes are found in southern Peru. In 2005, an exploration company, Cardero Resources, discovered

6006-551: The open-hearth furnace. It rapidly superseded both the Bessemer and Siemens–Martin processes in western Europe by the 1950s and in eastern Europe by the 1980s. Open-hearth steelmaking had superseded the Bessemer process in UK by 1900, but elsewhere in Europe, especially in Germany, the Bessemer and Thomas processes were used until the late 1960s when they were superseded by basic oxygen steelmaking. The last open-hearth furnace in former East Germany

6097-670: The oxygen content of the atmosphere of the Earth. Large deposits of magnetite are also found in the Atacama region of Chile ( Chilean Iron Belt ); the Valentines region of Uruguay; Kiruna , Sweden; the Tallawang region of New South Wales; and in the Adirondack Mountains of New York in the United States. Kediet ej Jill , the highest mountain of Mauritania , is made entirely of

6188-608: The port at the Seybouse river to the Karezas mine site was extended to the mine at Ain Mokra. The extension opened in 1864 and brought the total length of the railway line to 35 km. At that time the mine employed 3,000 people, mainly Italians. Full-scale production began in 1865. Before the mine was opened Bône had 10,000 inhabitants. By 1924 there were 41,000 and the port was being used to export phosphates, lead and zinc ore. The arrival in large volumes of Algerian ores from Mokta-el-Hadid upset

6279-584: The port, considerably reducing transport costs. Alphonse Parran remained head of the company until 1900. Philippe de Cerner took over management of the Mokta-el-Hadid mine in 1875. Output from the 14 iron ore mines in Algeria rose to 511,000 tons in 1876, then started to decline. In 1879 the country exported 400,000 tons, of which 320,000 tons came from Mokta-el-Hadid. Very little of the ore was smelted before export. The port of Bône shipped only 148,695 tons of ore in 1893. Mining at Mokta el Hadid ended in 1904. The mine

6370-403: The presence of mineralizers such as 0.1   M HI or 2   M NH 4 Cl and at 0.207   MPa at 416–800 °C, magnetite grew as crystals whose shapes were a combination of rhombic-dodechahedra forms. The crystals were more rounded than usual. The appearance of higher forms was considered as a result from a decrease in the surface energies caused by the lower surface to volume ratio in

6461-405: The production of free radicals . Research suggests that beta-amyloid plaques and tau proteins associated with neurodegenerative disease frequently occur after oxidative stress and the build-up of iron. Some researchers also suggest that humans possess a magnetic sense, proposing that this could allow certain people to use magnetoreception for navigation. The role of magnetite in the brain

6552-533: The project was delayed and eventually cancelled. In May 1919 the company's miners went on strike in solidarity with strikers in other industries, but the strike quickly fizzled out. Mokta el Hadid was the largest mining company in Algeria until 1927, when it was overtaken by the Société de l'Ouenza . The Mokta el Hadid iron ore mining company was responsible for creation of SACEM in 1929. SACEM (Société anonyme chérifienne d'études minières), based in Casablanca, Morocco,

6643-534: The relationship between magnetite and ferritin . In tissue, magnetite and ferritin can produce small magnetic fields which will interact with magnetic resonance imaging (MRI) creating contrast. Huntington patients have not shown increased magnetite levels; however, high levels have been found in study mice. Due to its high iron content, magnetite has long been a major iron ore . It is reduced in blast furnaces to pig iron or sponge iron for conversion to steel . Audio recording using magnetic acetate tape

6734-427: The rounded crystals. Magnetite has been important in understanding the conditions under which rocks form. Magnetite reacts with oxygen to produce hematite , and the mineral pair forms a buffer that can control how oxidizing its environment is (the oxygen fugacity ). This buffer is known as the hematite-magnetite or HM buffer. At lower oxygen levels, magnetite can form a buffer with quartz and fayalite known as

6825-420: The sign of the magnetocrystalline anisotropy constant changes from positive to negative. The Curie temperature of magnetite is 580 °C (853 K; 1,076 °F). If magnetite is in a large enough quantity it can be found in aeromagnetic surveys using a magnetometer which measures magnetic intensities. Solid magnetite particles melt at about 1,583–1,597 °C (2,881–2,907 °F). Magnetite

6916-651: The simple title of Director while Léon de Nervo (1873–1973), the heir of Paulin Talabot, took the title of Managing Director. Léon de Nervo was also president of the Société Commerciale de Navigation, which operated three 6,800 ton cargo vessels that carried North African iron ore to European ports and to the US. Heurteau left in the 1920s to take a position as Managing Director at the Marles coal mines. André Duby joined as chief engineer of technical services in 1927, then became co-director with Léon de Nervo, and sole director in

7007-441: The steel has melted, slag-forming agents such as limestone are added. Atmospheric oxygen in contact with molten pig iron directly oxidizes the carbon in excess it contains to form carbon monoxide (CO). Additionally, Fe(II) present in iron(II) oxide (FeO) and other impurities also contribute to decarburize the pig iron by oxidizing carbon into CO and simultaneously reducing Fe(II) into metallic Fe. The formed carbon monoxide (CO)

7098-544: The steel much easier and faster. The work environment around an open-hearth furnace is said to be extremely dangerous, although that may be even more true of the environment around a basic oxygen or electric arc furnace. On the one hand, the process achieves lesser economies of scale than the Bessemer, so its steel was costlier in former's heyday, but on the other, it was more suitable for countries which couldn't produce lots of steel anyway due to limitations of natural resources. Basic oxygen steelmaking eventually replaced

7189-634: The supply chain in France. The success at the Firminy plant in making steel rails using only ore from the Algerian mines was a major argument for installation of furnaces based on the Martin process at Le Creusot . In 1865 Eugène Schneider had reached an agreement with Paulin Talabot to obtain a large supply of Algerian ore, making it possible to start intensive steel production. In 1865 Napoleon III came to Algeria and made

7280-453: The upper beak for magnetoreception , which (in conjunction with cryptochromes in the retina ) gives them the ability to sense the direction, polarity , and magnitude of the ambient magnetic field . Chitons , a type of mollusk, have a tongue-like structure known as a radula , covered with magnetite-coated teeth, or denticles . The hardness of the magnetite helps in breaking down food. Biological magnetite may store information about

7371-719: Was appointed a director of the Mokta company and a member of the Executive Committee. In 1962 he became vice-president and, at the end of 1962 replaced Henri Lafond as president of the SACEM subsidiary that exploited the Imini manganese deposits in Morocco. Henri Lafond was assassinated in Paris on 6 March 1963, apparently by an OAS member because he refused to support the OAS with the companies in his group. He

7462-462: Was called the Karezas mine. The company built a narrow-gauge railway to transport the iron ore from the mine to a harbour on the Seybouse River near Bône. The place was called Allélik and was 6 km south of Bône. It this place where also the ironworks and blast furnaces for processing the orelocated. The 11 km long railway with a gauge of 1.055 mm opened in 1853 and was the first railway built in Algeria, however not open to public transport. In 1857

7553-476: Was developed in the 1930s. The German magnetophon first utilized magnetite powder that BASF coated onto cellulose acetate before soon switching to gamma ferric oxide for its superior morphology. Following World War II , 3M Company continued work on the German design. In 1946, the 3M researchers found they could also improve their own magnetite-based paper tape, which utilized powders of cubic crystals, by replacing

7644-709: Was founded to exploit the Imini manganese mines. The ratio of Société Mokta El Hadid share prices to earnings fluctuated from 3.0 in 1929 up to 11.0 in 1933, falling back to 1.8 by 1937. After World War II (1939–45) the Mokta El Hadid iron ore belonged to the Mirabaud Group . As of 1950 the company was capitalized at 5.1 billion francs, one of the top 2 on the Paris Bourse . In 1951 the Société de l'Ouenza produced 60% of Algerian iron, 85% in Ouenza and 15% in Bou-Kadra. Mokta-el-Hadid

7735-408: Was made and in 1849 the government revoked the three Talabot concessions. In 1852 they were restored after Napoleon III had taken power. Meanwhile, Eugène de Bassano, a Paris entrepreneur better known as Marquis de Bassano, founded the Société Civile des Mines et Hauts Fourneaux des Karezas , which had the concession to exploit a deposit in Meboudja between Bône and Aïn-Mokra (now Berrahal ), which

7826-650: Was one of only two privately owned French colonial companies other than banks and railways with capital of over 20 million francs, the other being the Société Le Nickel in New Caledonia. In 1917 the Société Mokta El Hadid and the Société des Hauts Fourneaux de Rouen agreed to form a joint venture to exploit the Boukhadra deposits, which was supported by the minister Albert Thomas . However, the administration of governor Charles Lutaud submitted an alternative proposal to

7917-630: Was shut down in 2001. The process in the form of Twin Hearth Furnace was in use in India's Steel Authority of India Bhilai Steel Plant and some parts of Ukraine. Russia retired its last hearth furnace in March 2018, and was considering preserving it as a museum artifact. India's SAIL shut it down in April 2020 with the advent of COVID19 because of nonavailability of manpower to run the labor intensive process. As of 2024,

8008-507: Was spent on Algerian public works. After experiencing some financial difficulties the SGA was reorganized as the Compagnie Algérienne in 1877. In 1865 the mine produced 22,000 tons, rising to 255,000 tons in 1869. The abundant ore was extracted from underground galleries and shipped from Bône to the main French steelworks. In 1870 Algeria as a whole exported 84,710 tons of iron ore. In the 1870s 2/3 of all miners in Algeria were working

8099-461: Was stopped in 1993. In the US, steel production using the Bessemer process ended in 1968 and the open-hearth furnaces had stopped by 1992. In Hunedoara steel works , Romania the last 420-tonne capacity open-hearth furnace was shut down on 12 June 1999 and demolished and scrapped between 2001 and 2003, but the eight smokestacks of the furnaces remained until February 2011. The last open-hearth shop in China

8190-641: Was succeeded as head of the Mokta company by Perrineau, who also became head of the Compagnie des Mines de Huaron, in which Mokta had a large stake. Perrineau was president of Mokta until 1970. In 1965 Perrineau presided over the company's centenary celebrations in Côte-d'Ivoire, which were attended by President Félix Houphouët-Boigny . In 1965 the company took a minority stake in the company formed to exploit chromium ore in Madagascar, directed by Ugine. In July 1967 France and Niger made agreements that included recognition of

8281-494: Was the second iron ore mining company in Algeria, with many subsidiaries and several concessions, including in Morocco. Henri Lafond was head of the Banque de l'Union Parisienne from 1951, which controlled Mokta El Hadid, and was also head of SACEM. Lafond headed the Mokta company until his death in 1963. On 24 April 1953 a joint corporation was established to mine a deposit estimated at 50 million tons of manganese ore in Gabon owned by

#924075