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Deville Process
The Deville process was the first industrial process used to produce alumina from bauxite. The Frenchman Henri Sainte-Claire Deville invented the process in 1859. It is sometimes called the Deville-Pechiney process. It is based on the extraction of alumina with sodium carbonate. The first stage is the calcination of the bauxite at 1200 °C with sodium carbonate and coke. The alumina is converted in sodium aluminate. Iron oxide remains unchanged and silica forms a polysilicate. In the second stage sodium hydroxide solution is added, which dissolves the sodium aluminate, leaving the impurities as a solid residue. The amount of sodium hydroxide solution needed depends upon the amount of silica present in the raw material. The solution is filtered off; carbon dioxide is bubbled through the solution, causing aluminium hydroxide to precipitate, leaving a solution of sodium carbonate. The latter can be recovered and reused in the first stage. The aluminium hydroxide i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcined
Calcination refers to thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition. The root of the word calcination refers to its most prominent use, which is to remove carbon from limestone (calcium carbonate) through combustion to yield calcium oxide (quicklime). This calcination reaction is CaCO3(s) → CaO(s) + CO2(g). Calcium oxide is a crucial ingredient in modern cement, and is also used as a chemical flux in smelting. Industrial calcination generally emits carbon dioxide (), making it a major contributor to climate change. A calciner is a steel cylinder that rotates inside a heated furnace and performs indirect high-temperature processing (550–1150 °C, or 1000–2100 °F) within a controlled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Industrial Processes
Industrial processes are procedures involving chemical, physical, electrical or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry. Chemical processes by main basic material Certain chemical process yield important basic materials for society, e.g., (cement, steel, aluminum, and fertilizer). However, these chemical reactions contribute to climate change by emitting carbon dioxide, a greenhouse gas, through chemical reactions, as well as through the combustion of fossil fuels to generate the high temperatures needed to reach the activation energies of the chemical reactions. Cement (the paste within concrete) * Calcination – Limestone, which is largely composed of fossilized calcium carbonate (CaCO3), breaks down at high temperatures into useable calcium oxide (CaO) and carbon dioxide gas (), which gets released as a by-product. This chemical reaction, call ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbite Process
Orbite Technologies Inc. was a Canadian cleantech company based in Montreal, Canada. It specialized in extracting processes for mining industry, especially alumina extraction. Its main asset is the Orbite process which can be used as a cheaper and pollution-free replacement of the Bayer process as well as a way to treat red mud.http://www.orbitealuminae.com/media/upload/filings/Red_Mud_Version_1_3.pdf, February 19, 2014 In April 2017, the company declared bankruptcy, due to ongoing delays and issues relating to its construction of a new plant in Cap-Chat, Quebec. As of January 2018, the bankruptcy process was still ongoing. As of 2022 the company has rebranded itself as Advanced Energy Minerals, and claims to be manufacturing high purity alumina at its new Cap-Chat plant. Orbite process The Orbite process is an industrial means to refine aluminum ores (such as bauxite) to produce alumina (aluminum oxide) patented by Orbite Alumnae using acid rather than sodium hydroxide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Aluminium
Aluminium (or aluminum) metal is very rare in native form, and the process to refine it from ores is complex, so for most of human history it was unknown. However, the compound alum has been known since the 5th century BCE and was used extensively by the ancients for dyeing. During the Middle Ages, its use for dyeing made it a commodity of international commerce. Renaissance scientists believed that alum was a salt of a new earth; during the Age of Enlightenment, it was established that this earth, alumina, was an oxide of a new metal. Discovery of this metal was announced in 1825 by Danish physicist Hans Christian Ørsted, whose work was extended by German chemist Friedrich Wöhler. Aluminium was difficult to refine and thus uncommon in actual usage. Soon after its discovery, the price of aluminium exceeded that of gold. It was reduced only after the initiation of the first industrial production by French chemist Henri Étienne Sainte-Claire Deville in 1856. In 1878, metallurg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Chemical Education
The ''Journal of Chemical Education'' is a monthly peer-reviewed academic journal available in both print and electronic versions. It is published by the Division of Chemical Education of the American Chemical Society The American Chemical Society (ACS) is a scientific society based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has more than 155,000 members at all ... and was established in 1924 by Neil Gordon. The journal covers research on chemical education, and its target audience includes instructors of chemistry from middle school through graduate school and some scientists in commerce, industry, and government. References External links * Chemical education journals American Chemical Society academic journals Monthly journals Publications established in 1924 English-language journals {{chemistry-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Materials Engineering And Performance
The ''Journal of Materials Engineering and Performance'' is a monthly peer-reviewed scientific journal published by Springer Science+Business Media on behalf of ASM International. The editor-in-chief is Rajiv Asthana (University of Wisconsin). The journal covers all aspects of materials engineering broadly described as materials selection, design, processing, characterization, and evaluation. The scope includes all substances used in engineering applications with a tendency toward constituent materials that comprise a larger system. Abstracting and indexing This journal is abstracted and indexed by: According to the ''Journal Citation Reports'', the journal has a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as ... of 1.819. References External links * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayer Process
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer. Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al2O3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. The aluminium oxide must be further purified before it can be refined into aluminium metal. Process Bauxite ore is a mixture of hydrated aluminium oxides and compounds of other elements such as iron. The aluminium compounds in the bauxite may be present as gibbsite 2(Al(OH)3), böhmite (γ-AlO(OH)) or diaspore (α-AlO(OH)); the different forms of the aluminium component and the impurities dictate the extraction conditions. Aluminum oxides and hydroxides are amphoteric, meaning that they are both acidic and basic. The solubility of Al(III) in water is very low but increases substantially at either high or low pH. In the Bayer process, bauxite ore is heated i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salindres
Salindres () is a commune in the Gard department in southern France. The composer and conductor Roger Dumas (1897–1951) was born, in Salindres. Geography Climate Salindres has a hot-summer Mediterranean climate (Köppen climate classification ''Csa''). The average annual temperature in Salindres is . The average annual rainfall is with September as the wettest month. The temperatures are highest on average in July, at around , and lowest in January, at around . The highest temperature ever recorded in Salindres was on 1 August 1947; the coldest temperature ever recorded was on 12 February 1956. Population See also *Communes of the Gard department This is a list of the 351 communes of the Gard department of France. The communes cooperate in the following intercommunalities (as of 2020): [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitate
In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution. The solid formed is called the precipitate. In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the ''precipitant''. The clear liquid remaining above the precipitated or the centrifuged solid phase is also called the 'supernate' or 'supernatant'. The notion of precipitation can also be extended to other domains of chemistry (organic chemistry and biochemistry) and even be applied to the solid phases (''e.g.'', metallurgy and alloys) when solid impurities segregate from a solid phase. Supersaturation The precipitation of a compound may occur when its concentration exceeds its solubility. This can be due to temperature changes, solvent evaporation, or by mixing solvents. Precipitation occurs more rapidly from a strongly supersaturated solution. The formati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bauxite
Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite (FeO(OH)) and haematite (Fe2O3), the aluminium clay mineral kaolinite (Al2Si2O5(OH)4) and small amounts of anatase (TiO2) and ilmenite (FeTiO3 or FeO.TiO2). Bauxite appears dull in luster and is reddish-brown, white, or tan. In 1821, the French geologist Pierre Berthier discovered bauxite near the village of Les Baux in Provence, southern France. Formation Numerous classification schemes have been proposed for bauxite but, , there was no consensus. Vadász (1951) distinguished lateritic bauxites (silicate bauxites) from karst bauxite ores (carbonate bauxites): * The carbonate bauxites occur predominantly in Europe, Guyana, Suriname, and Jamaica above carbonate rocks (limesto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Hydroxide
Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic and acidic properties. Closely related are aluminium oxide hydroxide, AlO(OH), and aluminium oxide or alumina (Al2O3), the latter of which is also amphoteric. These compounds together are the major components of the aluminium ore bauxite. Aluminium hydroxide also forms a gelatinous precipitate in water. Structure Al(OH)3 is built up of double layers of hydroxyl groups with aluminium ions occupying two-thirds of the octahedral holes between the two layers. Four polymorphs are recognized. All feature layers of octahedral aluminium hydroxide units, with hydrogen bonds between the layers. The polymorphs differ in terms of the stacking of the layers. All forms of Al(OH)3 crystals are hexagonal : *gibbsite is also known as γ-Al(OH)3 or α-Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
