Plate glass , flat glass or sheet glass is a type of glass , initially produced in plane form, commonly used for windows , glass doors, transparent walls, and windscreens . For modern architectural and automotive applications, the flat glass is sometimes bent after production of the plane sheet. Flat glass stands in contrast to container glass (used for bottles, jars, cups) and glass fibre (used for thermal insulation , in fibreglass composites, and for optical communication ).
28-504: Flat glass has a higher magnesium oxide and sodium oxide content than container glass, and a lower silica, calcium oxide , and aluminium oxide content. From the lower soluble oxide content comes the better chemical durability of container glass against water, which is required especially for storage of beverages and food. Most flat glass is soda–lime glass , produced by the float glass process (1950s). Other processes for making flat glass include: The term plate glass universities
56-457: A refractory (or refractory material ) is a material that is resistant to decomposition by heat or chemical attack and that retains its strength and rigidity at high temperatures . They are inorganic , non-metallic compounds that may be porous or non-porous, and their crystallinity varies widely: they may be crystalline , polycrystalline , amorphous , or composite . They are typically composed of oxides , carbides or nitrides of
84-554: 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 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
112-434: A "sleek" or hairline scratch, as well as "crush" or "rub" on the surface. Magnesium oxide 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
140-463: A dry powder, usually with a magnesia/alumina composition with additions of other chemicals for altering specific properties. They are also finding more applications in blast furnace linings, although this use is still rare. Refractory materials are classified into three types based on fusion temperature (melting point). Refractoriness is the property of a refractory's multiphase to reach a specific softening degree at high temperature without load, and
168-499: 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
196-539: 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
224-1005: A standard dimension of 9 in × 4.5 in × 2.5 in (229 mm × 114 mm × 64 mm) and this dimension is called a "one brick equivalent". "Brick equivalents" are used in estimating how many refractory bricks it takes to make an installation into an industrial furnace. There are ranges of standard shapes of different sizes manufactured to produce walls, roofs, arches, tubes and circular apertures etc. Special shapes are specifically made for specific locations within furnaces and for particular kilns or furnaces. Special shapes are usually less dense and therefore less hard wearing than standard shapes. These are without prescribed form and are only given shape upon application. These types are known as monolithic refractories. Common examples include plastic masses, ramming masses , castables, gunning masses, fettling mix, and mortars. Dry vibration linings often used in induction furnace linings are also monolithic, and sold and transported as
252-475: Is also known. According to evolutionary crystal structure prediction, MgO 2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and 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
280-628: Is important e. g. when removing phosphorus from pig iron (see Gilchrist–Thomas process ). The main raw materials belong to the RO group, of which magnesia (MgO) is a common example. Other examples include dolomite and chrome-magnesia. For the first half of the twentieth century, the steel making process used artificial periclase (roasted magnesite ) as a furnace lining material. These are used in areas where slags and atmosphere are either acidic or basic and are chemically stable to both acids and bases. The main raw materials belong to, but are not confined to,
308-500: Is measured with a pyrometric cone equivalent (PCE) test. Refractories are classified as: Refractories may be classified by thermal conductivity as either conducting, nonconducting, or insulating. Examples of conducting refractories are silicon carbide (SiC) and zirconium carbide (ZrC), whereas examples of nonconducting refractories are silica and alumina. Insulating refractories include calcium silicate materials, kaolin , and zirconia. Insulating refractories are used to reduce
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#1732801993518336-488: 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
364-603: 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 . Refractory In materials science ,
392-438: Is the most refractory binary compound known, with a melting point of 3890 °C. The ternary compound tantalum hafnium carbide has one of the highest melting points of all known compounds (4215 °C). Molybdenum disilicide has a high melting point of 2030 °C and is often used as a heating element . Refractory materials are useful for the following functions: Refractories have multiple useful applications. In
420-634: Is the oxide of calcium ( lime ). Fire clays are also widely used in the manufacture of refractories. Refractories must be chosen according to the conditions they face. Some applications require special refractory materials. Zirconia is used when the material must withstand extremely high temperatures. Silicon carbide and carbon ( graphite ) are two other refractory materials used in some very severe temperature conditions, but they cannot be used in contact with oxygen , as they would oxidize and burn. Binary compounds such as tungsten carbide or boron nitride can be very refractory. Hafnium carbide
448-686: Is the refractory industry, which consumed about 56% of the magnesia in the United States in 2004, 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
476-522: 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
504-462: Is used in the United Kingdom to describe a group – or generation – of universities (in an acknowledgement of the term red brick universities , used for an older generation of establishments). Scratches can occur on sheet of glass from accidental causes. In glass trade terminology these include "block reek" produced in polishing, "runner-cut" or “over/under grind” caused by edge grinding, or
532-646: 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
560-413: The R 2 O 3 group. Common examples of these materials are alumina (Al 2 O 3 ), chromia (Cr 2 O 3 ) and carbon. Refractory objects are manufactured in standard shapes and special shapes. Standard shapes have dimensions that conform to conventions used by refractory manufacturers and are generally applicable to kilns or furnaces of the same types. Standard shapes are usually bricks that have
588-409: The available surface area and produces dead-burned (often called dead burnt) magnesia, an unreactive form used as 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
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#1732801993518616-438: The carbonate to oxide occurs at temperatures below 700 °C, the resulting materials appear to reabsorb carbon dioxide from 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
644-414: 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
672-1050: The following elements: silicon , aluminium , magnesium , calcium , boron , chromium and zirconium . Many refractories are ceramics , but some such as graphite are not, and some ceramics such as clay pottery are not considered refractory. Refractories are distinguished from the refractory metals , which are elemental metals and their alloys that have high melting temperatures. Refractories are defined by ASTM C71 as "non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 1,000 °F (811 K; 538 °C)". Refractory materials are used in furnaces , kilns , incinerators , and reactors . Refractories are also used to make crucibles and molds for casting glass and metals. The iron and steel industry and metal casting sectors use approximately 70% of all refractories produced. Refractory materials must be chemically and physically stable at high temperatures. Depending on
700-1159: The metallurgy industry, refractories are used for lining furnaces, kilns, reactors, and other vessels which hold and transport hot media such as metal and slag . Refractories have other high temperature applications such as fired heaters, hydrogen reformers, ammonia primary and secondary reformers, cracking furnaces, utility boilers, catalytic cracking units, air heaters, and sulfur furnaces. They are used for surfacing flame deflectors in rocket launch structures. Refractories are classified in multiple ways, based on: Acidic refractories are generally impervious to acidic materials but easily attacked by basic materials, and are thus used with acidic slag in acidic environments. They include substances such as silica , alumina , and fire clay brick refractories. Notable reagents that can attack both alumina and silica are hydrofluoric acid, phosphoric acid, and fluorinated gases (e.g. HF, F 2 ). At high temperatures, acidic refractories may also react with limes and basic oxides. Basic refractories are used in areas where slags and atmosphere are basic. They are stable to alkaline materials but can react to acids, which
728-751: 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
756-406: The operating environment, they must be resistant to thermal shock , be chemically inert , and/or have specific ranges of thermal conductivity and of the coefficient of thermal expansion . The oxides of aluminium ( alumina ), silicon ( silica ) and magnesium ( magnesia ) are the most important materials used in the manufacturing of refractories. Another oxide usually found in refractories
784-415: The presence of water (MgO + H 2 O → Mg(OH) 2 ), but it can be reversed by heating it to remove moisture. Magnesium oxide 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
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