People have tried to produce aluminium since 1760. The first successful attempt, finished in 1824 by Danish physicist and chemist Hans Christian Ørsted. He reacted anhydrous aluminium chloride with potassium amalgam, yielding a lump of metal looking similar totin. He presented his results and showed a sample of the new metal in 1825.[9] In 1827, German chemist Friedrich Wöhler repeated Ørsted's experiments but did not identify any aluminium.[10] (The reason for this inconsistency was only discovered in 1921.) He conducted a similar experiment in the same year by mixing anhydrous aluminium chloride with potassium and produced a powder of aluminium.[11] In 1845, he was able to produce small pieces of the metal and described some physical properties of this metal. For many years thereafter, Wöhler was credited as the person who discovered aluminium.
A fresh film of aluminium is a good reflector of visible light and an excellent reflector of medium and farinfrared radiation.
Aluminium prevents corrosion by forming a small, thinlayer ofaluminium oxide on itssurface. This layer protects the metal by preventing oxygen from reaching it. Corrosion can not occur without oxygen. Because of this thin layer, the reactivity of aluminium is not seen. As a powder it burns hot. Uses includefireworks displays androcket fuel.
Pure aluminium is made frombauxite, a kind ofrock that hasaluminium oxide and manyimpurities. The bauxite is crushed and reacted withsodium hydroxide. The aluminium oxide dissolves. Then the aluminium oxide is dissolved in liquidcryolite. Natural cryolite is a raremineral, so most is produced artificially. The aluminium oxide iselectrolyzed with carbon to make aluminium andcarbon dioxide. The largest producer of aluminium isChina. China produces about 31,873 thousand tonnes of aluminium.
Aluminium was once considered aprecious metal that was even more valuable thangold[verification needed]. This is no longer true because new ways ofsmelting it are cheaper and easier.
Aluminium is the 12th most abundant of all elements. It is the 3rd most abundant among the elements that have odd atomic numbers.[12] The only stable isotope of aluminium is aluminium-27. It is the 18th most abundantnucleus in theUniverse. It is created after fusion of carbon in massive stars that will later become Type IIsupernovae: this fusion creates magnesium-26, which, when capturing free protons and neutrons becomes aluminium. Essentially all aluminium now in existence is aluminium-27;aluminium-26 was there in the early Solar System but is now extinct. The trace quantities of aluminium-26 that do exist are the most commongamma ray emitter in theinterstellar gas.[13]
Overall, theEarth is about 1.59% aluminium by mass.[14] In theEarth's crust, aluminium is the most abundant metallic element by mass (8.23%). It is also the third most abundant of all elements in the Earth's crust. A lot ofsilicates in the Earth's crust contain aluminium.[15] But, theEarth's mantle is only 2.38% aluminium by mass. aluminium also occurs in seawater at a concentration of 2 μg/kg.[16]
Many things are made of aluminium. Much of it is used in overheadpower lines. It is also widely used inwindow frames andaircraft bodies. It is found at home askitchenware,soft drink cans, and cooking foil. aluminium is also used to coatcarheadlamps andcompact discs. It is used in electrical transmission lines because of its light weight. It can bedeposited on the surface of glass to makemirrors, where a thin layer ofaluminium oxide quickly forms that acts as a protective coating. Aluminium oxide is also used to make syntheticrubies andsapphires forlasers. Aluminium can now be produced from clay, but the process is not economically feasible at today.
Pure aluminium is very soft, so a harder metal is almost always added. The harder metal is usuallycopper. Copper/aluminiumalloys are to makeships, because the aluminium prevents corrosion, and the copper preventsbarnacles.
Aluminium hydroxychlorides are used in purifying water, in thepaper industry, and as antiperspirants. Sodium aluminate is used in treating water and as an accelerator for drying ofcement.
Aluminium phosphate is used to makeglass,ceramic, pulp and paper products, cosmetics, paints,varnishes.aluminium hydroxide is used as anantacid, and mordant. It is used also in water purification, the manufacture of glass and ceramics, and in thewaterproofing offabrics.
Since aluminium needs to be made byelectrolysis, it requires a very large amount of electrical power. Recycling aluminium would be much cheaper. That's why recycling plants were opened. The cost of recycling aluminium is much less than the cost of making it frombauxite.
Recycling involves melting the scrap. This is a process that only needs 5% of the energy used to produce aluminium from ore. But, 15% of the input material part is lost as dross (ash-like oxide).[18] An aluminium stack melter makes a lot less dross, about 1%.[19]
White dross from primary aluminium production and from secondary recycling processes still contains useful amounts of aluminium that can be extracted industrially. The process produces aluminium billets, together with a very complexwaste. This waste is difficult to manage. It reacts with water, releasing a mixture of gases (including, hydrogen, acetylene, and ammonia), which ignites on contact with air.[20] Even with these difficulties, the waste is used as a filler inasphalt and concrete.[21]
Aluminium is not used in the human body, although it is very common. People debate whether its use in deodorants and water treatment is healthy. aluminium ions slow down plant growth inacidic soils. aluminium may be a factor inAlzheimer's disease (a disease when the brain stops working and the patient is confused).[22][23] But theAlzheimer's Society says overwhelming medical and scientific opinion is that studies have not convincingly demonstrated a causal relationship between aluminium and Alzheimer's disease.[24]
In most people, aluminium is not as toxic as heavy metals. aluminium is classified as a non-carcinogen by United States Department of Health and Human Services. There is little proof that normal exposure to aluminium is a risk to healthy adult. There is proof of no toxicity if it is taken in amounts not greater than 40mg/day per kg of body mass.[25] Most aluminium taken will leave the body infeces. Most of the small part that enters theblood, will beexcreted viaurine.[26]
Aluminium rarely causes vitamin D-resistant osteomalacia, erythropoietin-resistant microcytic anemia, and central nervous system changes. People with kidney insufficiency are at a risk the most. Chronic ingestion of hydrated aluminium silicates may result in aluminium binding to the things in the intestines. It also increases the removal of other metals, likeiron orzinc. Really high doses (>50 g/day) can causeanemia.
Food is the main source of aluminium.Drinking water has more aluminium than solid foods.[28] Aluminium in food may be absorbed more than aluminium from water. Major sources of human exposure by mouth to aluminium include food (because of its use infood additives, food and beverage packaging, and cooking utensils), drinking water (because of its use inwater treatment), and medicines that have aluminium in them.[29] Very high exposure to aluminium is mostly limited to miners, aluminium production workers, and dialysis patients.[30]
Taking ofantacids, antiperspirants,vaccines, and cosmetics give possible ways ofexposure.[31] Eating acidic foods or liquids with aluminium increases aluminium absorption. Maltol has been shown to increase the build up of aluminium in nerve and bone tissues.[32]
In case of suspected sudden consumption of a large amount of aluminium, the only treatment isdeferoxamine mesylate. It may be given to help remove aluminium from the body bychelation.[33][34] This should be applied with caution as it not only remove aluminium in the body, but also othermetals such ascopper oriron.[33]
High levels of aluminium occur near mining sites. Small amounts of aluminium are released to the environment at the coal-fired power plants or incinerators. aluminium in the air is washed out by the rain or normally settles down. But, small particles of aluminium remain in the air for a long time.[26]
Acid rain is the main natural factor to move aluminium from natural sources. It is also the main reason for the effects of aluminium on the environment.[35] The main factor for the presence of aluminium insalt andfreshwater are the industrial processes that also release aluminium intoair.[36]
Aluminium is one of the primary factors that reduce the growth of plants on acidic soils. In acid soils the concentration of toxic Al3+cations increases and disturbs the growth and function of theroot. It is generally harmless to plant growth in pH-neutral soils.[37][38][39][40] Wheat has developed a tolerance to aluminium. It releasesorganic compounds that bind to harmful aluminium cations.Sorghum is thought to have the same method of tolerating aluminium.[41]
Aluminium production has its own problems to the environment on each step of the production process. The major problem is thegreenhouse gas. These gases are caused by the electrical consumption of the smelters and the byproducts of processing. The strongest of these gases are perfluorocarbons from the smelting process.[30]
Pure (white) and impure (yellow) forms of aluminium chlorideA roll of aluminiumBauxite, aluminium orealuminium cans ready for recycling at Central European Waste Management's plant in Europe
↑Dohmeier, C.; Loos, D.; Schnöckel, H. (1996). "Aluminum(I) and Gallium(I) Compounds: Syntheses, Structures, and Reactions".Angewandte Chemie International Edition.35 (2):129–149.doi:10.1002/anie.199601291.
↑United States. Agency for Toxic Substances and Disease Registry, issuing body.Toxicological profile for aluminum.OCLC832737188.
12"Aluminum".The Environmental Literacy Council. Archived fromthe original on 2020-10-27. Retrieved2020-08-28.
↑Chen, Jennifer K.; Thyssen, Jacob P., eds. (13 April 2018).Metal allergy: from dermatitis to implant and device failure. Springer.ISBN978-3-319-58503-1.OCLC1031466049.
↑van Ginkel, M. F.; van der Voet, G. B.; D'Haese, P. C.; De Broe, M. E.; de Wolff, F. A. (March 1993). "Effect of citric acid and maltol on the accumulation of aluminium in rat brain and bone".The Journal of Laboratory and Clinical Medicine.121 (3):453–460.ISSN0022-2143.PMID8445293.
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