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52-453: Magnesium oxide ( Mg O ), 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 Mg ions and O ions held together by ionic bonding . Magnesium hydroxide forms in the presence of water (MgO + H 2 O → Mg(OH) 2 ), but it can be reversed by heating it to remove moisture. Magnesium oxide

104-507: A carbon nucleus. When such stars explode as supernovas , much of the magnesium is expelled into the interstellar medium where it may recycle into new star systems. Magnesium is the eighth most abundant element in the Earth's crust and the fourth most common element in the Earth (after iron , oxygen and silicon ), making up 13% of the planet's mass and a large fraction of the planet's mantle . It

156-489: A half-life of 717,000 years. Excessive quantities of stable Mg have been observed in the Ca-Al-rich inclusions of some carbonaceous chondrite meteorites . This anomalous abundance is attributed to the decay of its parent Al in the inclusions, and researchers conclude that such meteorites were formed in the solar nebula before the Al had decayed. These are among

208-490: A magnesium-based engine . Magnesium also reacts exothermically with most acids such as hydrochloric acid (HCl), producing magnesium chloride and hydrogen gas, similar to the HCl reaction with aluminium, zinc, and many other metals. Although it is difficult to ignite in mass or bulk, magnesium metal will ignite. Magnesium may also be used as an igniter for thermite , a mixture of aluminium and iron oxide powder that ignites only at

260-422: A refractory . Calcining temperatures 1000 – 1500 °C produce hard-burned magnesia, which has limited reactivity and calcining at lower temperature, (700–1000 °C) produces light-burned magnesia, a reactive form, also known as caustic calcined magnesia. Although some decomposition of the carbonate to oxide occurs at temperatures below 700 °C, the resulting materials appear to reabsorb carbon dioxide from

312-479: A common reservoir. Magnesium is the eighth-most-abundant element in the Earth's crust by mass and tied in seventh place with iron in molarity . It is found in large deposits of magnesite , dolomite , and other minerals , and in mineral waters, where magnesium ion is soluble. Although magnesium is found in more than 60 minerals , only dolomite , magnesite , brucite , carnallite , talc , and olivine are of commercial importance. The Mg cation

364-488: A good choice as a reinforcement in composites. It is used extensively as an electrical insulator in tubular construction heating elements as in electric stove and cooktop 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

416-506: A high purity product is easily achievable. China is almost completely reliant on the silicothermic Pidgeon process . Besides the Pigeon process, the second most used process for magnesium production is electrolysis . This is a two step process. The first step is to prepare feedstock containing magnesium chloride and the second step is to dissociate the compound in electrolytic cells as magnesium metal and chlorine gas . The basic reaction

468-502: A semiconducting suboxide Mg 3 O 2 is thermodynamically stable above 500 GPa. Because of its stability, MgO is used as a model system for investigating vibrational properties of crystals. Pure MgO is not conductive and has a high resistance to electric current at room temperature . The pure powder of MgO has a relative permittivity inbetween 3.2 to 9.9 k {\displaystyle k} with an approximate dielectric loss of tan(δ) > 2.16x10 at 1kHz. Magnesium oxide

520-535: A severe downside as it attracts moisture and can cause moisture damage to surrounding materials. [1] Magnesium oxide is used for relief of heartburn and indigestion, as an antacid , magnesium supplement, and as a short-term laxative . It is also used to improve symptoms of indigestion . Side effects of magnesium oxide may include nausea and cramping. In quantities sufficient to obtain a laxative effect, side effects of long-term use may rarely cause enteroliths to form, resulting in bowel obstruction . Magnesium oxide

572-429: A solid solution with calcium oxide by calcining the mineral dolomite , which is a solid solution of calcium and magnesium carbonates: Reduction occurs at high temperatures with silicon. A ferrosilicon alloy is used rather than pure silicon as it is more economical. The iron component has no bearing on the reaction, having the simplified equation: The calcium oxide combines with silicon as the oxygen scavenger, yielding

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624-545: A variety of compounds important to industry and biology, including magnesium carbonate , magnesium chloride , magnesium citrate , magnesium hydroxide (milk of magnesia), magnesium oxide , magnesium sulfate , and magnesium sulfate heptahydrate ( Epsom salts ). As recently as 2020, magnesium hydride was under investigation as a way to store hydrogen. Magnesium has three stable isotopes : Mg , Mg and Mg . All are present in significant amounts in nature (see table of isotopes above). About 79% of Mg

676-408: A very high temperature. Organomagnesium compounds are widespread in organic chemistry . They are commonly found as Grignard reagents , formed by reaction of magnesium with haloalkanes . Examples of Grignard reagents are phenylmagnesium bromide and ethylmagnesium bromide . The Grignard reagents function as a common nucleophile , attacking the electrophilic group such as the carbon atom that

728-690: A wider group of foundrymen. They invited foundrymen from around the country to Philadelphia for a meeting. The response was spontaneous and well received. On May 12, 1896, the American Foundrymen's Association was formed. The organization's name was subsequently changed to The American Foundrymen's Society. In 2000, it was renamed as the American Foundry Society, or AFS. The Society has approximately 930 corporate members and 7,000 individual members. There are 40 regional chapters, as well as 40 student chapters at colleges and universities. AFS

780-510: A yearly industry conference, as well as CastExpo, a trade show and exposition that occurs every three years. AFS is based in Schaumburg, Illinois , and also maintains an office in Washington, D.C. Doug Kurkul is CEO of the organization. The American Foundry Society traces its roots to 1896, when the American Foundrymen's Association was formed. For a number of years prior to the founding of

832-438: Is Mg . The isotope Mg is radioactive and in the 1950s to 1970s was produced by several nuclear power plants for use in scientific experiments. This isotope has a relatively short half-life (21 hours) and its use was limited by shipping times. The nuclide Mg has found application in isotopic geology , similar to that of aluminium. Mg is a radiogenic daughter product of Al , which has

884-477: Is a chemical element ; it has symbol   Mg and atomic number  12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic table ) it occurs naturally only in combination with other elements and almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of

936-658: Is a gray-white lightweight metal, two-thirds the density of aluminium. Magnesium has the lowest melting (923 K (650 °C)) and the lowest boiling point (1,363 K (1,090 °C)) of all the alkaline earth metals. Pure polycrystalline magnesium is brittle and easily fractures along shear bands . It becomes much more malleable when alloyed with small amounts of other metals, such as 1% aluminium. The malleability of polycrystalline magnesium can also be significantly improved by reducing its grain size to about 1  μm or less. When finely powdered, magnesium reacts with water to produce hydrogen gas: However, this reaction

988-480: Is a liquid metal. At the YSZ/liquid metal anode O is oxidized. A layer of graphite borders the liquid metal anode, and at this interface carbon and oxygen react to form carbon monoxide. When silver is used as the liquid metal anode, there is no reductant carbon or hydrogen needed, and only oxygen gas is evolved at the anode. It was reported in 2011 that this method provides a 40% reduction in cost per pound over

1040-582: Is as follows: The temperatures at which this reaction is operated is between 680 and 750 °C. The magnesium chloride can be obtained using the Dow process , a process that mixes sea water and dolomite in a flocculator or by dehydration of magnesium chloride brines. The electrolytic cells are partially submerged in a molten salt electrolyte to which the produced magnesium chloride is added in concentrations between 6-18%. This process does have its share of disadvantages including production of harmful chlorine gas and

1092-479: Is first treated with lime (calcium oxide) and the precipitated magnesium hydroxide is collected: The hydroxide is then converted to magnesium chloride by treatment with hydrochloric acid and heating of the product to eliminate water: The salt is then electrolyzed in the molten state. At the cathode , the Mg ion is reduced by two electrons to magnesium metal: At the anode , each pair of Cl ions

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1144-441: Is much less dramatic than the reactions of the alkali metals with water, because the magnesium hydroxide builds up on the surface of the magnesium metal and inhibits further reaction. The principal property of magnesium metal is its reducing power. One hint is that it tarnishes slightly when exposed to air, although, unlike the heavier alkaline earth metals , an oxygen-free environment is unnecessary for storage because magnesium

1196-477: Is often blended into metals-contaminating soil or waste material, which is also commonly of a low pH (acidic), in order to drive the pH into the 8–10 range. Metal-hydroxide complexes tend to precipitate out of aqueous solution in the pH range of 8–10. MgO is packed in bags around transuranic waste in the disposal cells (panels) at the Waste Isolation Pilot Plant , as a CO 2 getter to minimize

1248-588: Is often used as a dielectric material or an insulator due to its high thermal stability, excellent insulating properties, and wide bandgap . Optimized IGZO/MgO TFTs demonstrated an electron mobility of 1.63 cm²/Vs, an on/off current ratio of 10⁶, and a subthreshold swing of 0.50 V/decade at −0.11 V. These TFTs are integral to low-power applications, wearable devices, and radiation-hardened electronics, contributing to enhanced efficiency and durability across diverse domains. Inhalation of magnesium oxide fumes can cause metal fume fever . Magnesium Magnesium

1300-835: Is organized into 13 Divisions with committees under each division: In addition to these divisions, the organization has technical staff to assist with engineering services, a system to support research, and an extensive library containing more than 15,000 articles available free of charge to all members. AFS also operates the AFS Institute , previously known as the Cast Metals Institute. The AFS Institute provides classroom training, web courses and e-learning for foundry professionals across all major alloys and foundry processes. Regional Chapters organize educational events and hold chapter meetings, usually at monthly intervals, to promote technical or business subjects related to foundries and

1352-401: Is oxidized to chlorine gas, releasing two electrons to complete the circuit: The carbothermic route to magnesium has been recognized as a low energy, yet high productivity path to magnesium extraction. The chemistry is as follows: C + MgO → CO + Mg A disadvantage of this method is that slow cooling the vapour can cause the reaction to quickly revert. To prevent this from happening,

1404-514: Is present within the polar bond of a carbonyl group. A prominent organomagnesium reagent beyond Grignard reagents is magnesium anthracene , which is used as a source of highly active magnesium. The related butadiene -magnesium adduct serves as a source for the butadiene dianion. Complexes of dimagnesium(I) have been observed. The presence of magnesium ions can be detected by the addition of ammonium chloride , ammonium hydroxide and monosodium phosphate to an aqueous or dilute HCl solution of

1456-481: Is produced by the calcination of magnesium carbonate or magnesium hydroxide . The latter is obtained by the treatment of magnesium chloride MgCl 2 solutions, typically seawater, with limewater or milk of lime. Calcining at different temperatures produces magnesium oxide of different reactivity. High temperatures 1500 – 2000 °C diminish the available surface area and produces dead-burned (often called dead burnt) magnesia, an unreactive form used as

1508-447: Is protected by a thin layer of oxide that is fairly impermeable and difficult to remove. Direct reaction of magnesium with air or oxygen at ambient pressure forms only the "normal" oxide MgO. However, this oxide may be combined with hydrogen peroxide to form magnesium peroxide , MgO 2 , and at low temperature the peroxide may be further reacted with ozone to form magnesium superoxide Mg(O 2 ) 2 . Magnesium reacts with nitrogen in

1560-541: Is the second-most-abundant cation in seawater (about 1 ⁄ 8 the mass of sodium ions in a given sample), which makes seawater and sea salt attractive commercial sources for Mg. To extract the magnesium, calcium hydroxide is added to the seawater to precipitate magnesium hydroxide . Magnesium hydroxide ( brucite ) is poorly soluble in water and can be collected by filtration. It reacts with hydrochloric acid to magnesium chloride . From magnesium chloride, electrolysis produces magnesium. World production

1612-600: Is the third most abundant element dissolved in seawater, after sodium and chlorine . This element is the eleventh most abundant element by mass in the human body and is essential to all cells and some 300 enzymes . Magnesium ions interact with polyphosphate compounds such as ATP , DNA , and RNA . Hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common laxatives and antacids (such as milk of magnesia ), and to stabilize abnormal nerve excitation or blood vessel spasm in such conditions as eclampsia . Elemental magnesium

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1664-521: 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. Many heavy metals species, such as lead and cadmium , are least soluble in water at mildly basic conditions (pH in the range 8–11). Solubility of metals increases their undesired bioavailability and mobility in soil and groundwater. Granular MgO

1716-639: Is usually crushed and compacted with minimal airgaps or voids. MgO is one of the components in Portland cement in dry process plants . Sorel cement uses MgO as the main component in combination with MgCl 2 and water. MgO has an important place as a commercial plant fertilizer and as animal feed. 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, but also

1768-463: The air. MgO is prized as a refractory material , i.e. a solid that is physically and chemically stable at high temperatures. It has the useful attributes of high thermal conductivity and low electrical conductivity. According to a 2006 reference book: 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,

1820-414: The complexation of uranium and other actinides by carbonate ions and so to limit the solubility of radionuclides . The use of MgO is preferred over CaO since the resulting hydration product ( Mg(OH) 2 ) is less soluble and releases less hydration heat . Another advantage is to impose a lower pH value (about 10.5) in case of accidental water ingress into the dry salt layers, in contast to

1872-573: The corrosion rate of magnesium in a salt solution by a factor of nearly ten. Magnesium's tendency to creep (gradually deform) at high temperatures is greatly reduced by alloying with zinc and rare-earth elements . Flammability is significantly reduced by a small amount of calcium in the alloy. By using rare-earth elements, it may be possible to manufacture magnesium alloys that are able to not catch fire at higher temperatures compared to magnesium's liquidus and in some cases potentially pushing it close to magnesium's boiling point. Magnesium forms

1924-551: The electrolytic reduction method. American Foundry Society AFS represents ferrous and nonferrous foundries based in North America, as well as industry suppliers and end-users of metal castings from around the world. The society has individual and corporate members across 48 countries, organized into regional chapters and student chapters in the United States , Canada and Mexico . AFS presents Metalcasting Congress,

1976-424: The magnesium can be dissolved directly in a suitable metal solvent before reversion starts happening. Rapid quenching of the vapour can also be performed to prevent reversion. A newer process, solid oxide membrane technology, involves the electrolytic reduction of MgO. At the cathode, Mg ion is reduced by two electrons to magnesium metal. The electrolyte is yttria-stabilized zirconia (YSZ). The anode

2028-402: The metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine . It is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium. In the cosmos , magnesium is produced in large, aging stars by the sequential addition of three helium nuclei to

2080-747: The more soluble Ca(OH) 2 which would create a higher pH of 12.5 (strongly alkaline conditions). The Mg cation being the second most abundant cation in seawater and in rocksalt , the potential release of magnesium ions dissolving in brines intruding the deep geological repository is also expected to minimize the geochemical disruption. Magnesia is used in brake linings for its heat conductivity and intermediate hardness. It helps dissipate heat from friction surfaces, preventing overheating, while minimizing wear on metal components. Its stability under high temperatures ensures reliable and durable braking performance in automotive and industrial applications. In thin film transistors(TFTs) , MgO

2132-530: The oldest objects in the Solar System and contain preserved information about its early history. It is conventional to plot Mg / Mg against an Al/Mg ratio. In an isochron dating plot, the Al/Mg ratio plotted is Al / Mg . The slope of the isochron has no age significance, but indicates the initial Al / Al ratio in the sample at the time when the systems were separated from

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2184-608: The overall reaction being very energy intensive, creating environmental risks. The Pidgeon process is more advantageous regarding its simplicity, shorter construction period, low power consumption and overall good magnesium quality compared to the electrolysis method. In the United States, magnesium was once obtained principally with the Dow process in Corpus Christi TX , by electrolysis of fused magnesium chloride from brine and sea water . A saline solution containing Mg ions

2236-443: The quantity of these metals improves corrosion resistance. Sufficient manganese overcomes the corrosive effects of iron. This requires precise control over composition, increasing costs. Adding a cathodic poison captures atomic hydrogen within the structure of a metal. This prevents the formation of free hydrogen gas, an essential factor of corrosive chemical processes. The addition of about one in three hundred parts arsenic reduces

2288-524: The remaining 44% being used in agricultural, chemical, construction, environmental, and other industrial applications. MgO is used as a refractory material for crucibles . It is also used as an insulator in heat-resistant electrical cable . Among metal oxide nanoparticles, magnesium oxide nanoparticles (MgO NPs) have distinct physicochemical and biological properties, including biocompatibility, biodegradability, high bioactivity, significant antibacterial properties, and good mechanical properties, which make it

2340-455: The salt. The formation of a white precipitate indicates the presence of magnesium ions. Azo violet dye can also be used, turning deep blue in the presence of an alkaline solution of magnesium salt. The color is due to the adsorption of azo violet by Mg(OH) 2 . As of 2013, magnesium alloys consumption was less than one million tonnes per year, compared with 50 million tonnes of aluminium alloys . Their use has been historically limited by

2392-518: The shores of the Great Salt Lake . In September 2021, China took steps to reduce production of magnesium as a result of a government initiative to reduce energy availability for manufacturing industries, leading to a significant price increase. The Pidgeon process and the Bolzano process are similar. In both, magnesium oxide is the precursor to magnesium metal. The magnesium oxide is produced as

2444-499: The society, many local bodies of foundrymen met for mutual protection in regard to labor, prices and interchange of technical information. The attendance was usually strong in these organizations in times of prosperity but waned when economic conditions slowed. Early in 1896 the Philadelphia Foundrymen's Society through discussion with its members conceived that a more general, larger benefit might be gained through organizing

2496-573: The solid state if it is powdered and heated to just below the melting point, forming Magnesium nitride Mg 3 N 2 . Magnesium reacts with water at room temperature, though it reacts much more slowly than calcium, a similar group 2 metal. When submerged in water, hydrogen bubbles form slowly on the surface of the metal; this reaction happens much more rapidly with powdered magnesium. The reaction also occurs faster with higher temperatures (see § Safety precautions ). Magnesium's reversible reaction with water can be harnessed to store energy and run

2548-403: The tendency of Mg alloys to corrode, creep at high temperatures, and combust. In magnesium alloys, the presence of iron , nickel , copper , or cobalt strongly activates corrosion . In more than trace amounts, these metals precipitate as intermetallic compounds , and the precipitate locales function as active cathodic sites that reduce water, causing the loss of magnesium. Controlling

2600-505: The very stable calcium silicate. The Mg/Ca ratio of the precursors can be adjusted by the addition of MgO or CaO. The Pidgeon and the Bolzano process differ in the details of the heating and the configuration of the reactor. Both generate gaseous Mg that is condensed and collected. The Pidgeon process dominates the worldwide production. The Pidgeon method is less technologically complex and because of distillation/vapour deposition conditions,

2652-609: Was approximately 1,100 kt in 2017, with the bulk being produced in China (930 kt) and Russia (60 kt). The United States was in the 20th century the major world supplier of this metal, supplying 45% of world production even as recently as 1995. Since the Chinese mastery of the Pidgeon process the US market share is at 7%, with a single US producer left as of 2013: US Magnesium, a Renco Group company located on

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2704-442: Was historically known as magnesia alba (literally, the white mineral from Magnesia ), to differentiate it from magnesia nigra , a black mineral containing what is now known as manganese . While "magnesium oxide" normally refers to MgO, the compound magnesium peroxide MgO 2 is also known. According to evolutionary crystal structure prediction, MgO 2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and

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