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.[11] In 1827, German chemist Friedrich Wöhler repeated Ørsted's experiments but did not identify any aluminium.[12] (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.[13] 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 aluminum is a good reflector of visible light and an excellent reflector of medium and farinfrared radiation.
Aluminum prevents corrosion by forming a small, thinlayer ofaluminum 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 aluminum is not seen. As a powder it burns hot. Uses includefireworks displays androcket fuel.
Pure aluminum is made frombauxite, a kind ofrock that hasaluminum oxide and manyimpurities. The bauxite is crushed and reacted withsodium hydroxide. The aluminum oxide dissolves. Then the aluminum oxide is dissolved in liquidcryolite. Natural cryolite is a raremineral, so most is produced artificially. The aluminum oxide iselectrolyzed with carbon to make aluminum andcarbon dioxide. The largest producer of aluminum isChina. China produces about 31,873 thousand tonnes of aluminum.
Aluminum 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.
Aluminum is the 12th most abundant of all elements. It is the 3rd most abundant among the elements that have odd atomic numbers.[14] The only stable isotope of aluminum is aluminum-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 aluminum. Essentially all aluminum now in existence is aluminum-27;aluminum-26 was there in the early Solar System but is now extinct. The trace quantities of aluminum-26 that do exist are the most commongamma ray emitter in theinterstellar gas.[15]
Overall, theEarth is about 1.59% aluminum by mass.[16] In theEarth's crust, aluminum 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 aluminum.[17] But, theEarth's mantle is only 2.38% aluminum by mass. aluminum also occurs in seawater at a concentration of 2 μg/kg.[18]
Many things are made of aluminum. 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, andcooking foil. aluminum 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 ofaluminum oxide quickly forms that acts as a protective coating. aluminum oxide is also used to make syntheticrubies andsapphires forlasers. aluminum can now be produced from clay, but the process is not economically feasible at today.
Pure aluminum is very soft, so a harder metal is almost always added. The harder metal is usuallycopper. Copper/aluminumalloys are to makeships, because the aluminum prevents corrosion, and the copper preventsbarnacles.
aluminum 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.
aluminum phosphate is used to makeglass,ceramic, pulp and paper products, cosmetics, paints,varnishes.aluminum 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 aluminum needs to be made byelectrolysis, it requires a very large amount of electrical power. Recycling aluminum would be much cheaper. That's why recycling plants were opened. The cost of recycling aluminum 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 Aluminum from ore. But, 15% of the input material part is lost as dross (ash-like oxide).[20] An aluminum stack melter makes a lot less dross, about 1%.[21]
White dross from primary aluminum production and from secondary recycling processes still contains useful amounts of aluminum that can be extracted industrially. The process produces aluminum 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.[22] Even with these difficulties, the waste is used as a filler inasphalt and concrete.[23]
Aluminum is not used in the human body, although it is very common. People debate whether its use in deodorants and water treatment is healthy. Aluminum ions slow down plant growth inacidic soils. Aluminum may be a factor inAlzheimer's disease (a disease when the brain stops working and the patient is confused).[24][25] But theAlzheimer's Society says overwhelming medical and scientific opinion is that studies have not convincingly demonstrated a causal relationship between aluminum and Alzheimer's disease.[26]
In most people, aluminum is not as toxic as heavy metals. Aluminum is classified as a non-carcinogen by United States Department of Health and Human Services. There is little proof that normal exposure to aluminum is a risk to healthy adult. There is proof of no toxicity if it is taken in amounts not greater than 40 mg/day per kg of body mass.[27] Most aluminum taken will leave the body infeces. Most of the small part that enters theblood, will beexcreted viaurine.[28]
aluminum 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 aluminum silicates may result in aluminum 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 aluminum.Drinking water has more aluminum than solid foods.[30] aluminum in food may be absorbed more than aluminum from water. Major sources of human exposure by mouth to aluminum 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 aluminum in it.[31] Very high exposure of aluminum are mostly limited to miners, aluminum production workers, and dialysis patients.[32]
Taking ofantacids, antiperspirants,vaccines, and cosmetics give possible ways ofexposure.[33] Eating acidic foods or liquids with aluminum increases Aluminum absorption. Maltol has been shown to increase the build up of aluminum in nerve and bone tissues.[34]
In case of suspected sudden consumption of a large amount of aluminum, the only treatment isdeferoxamine mesylate. It may be given to help remove aluminum from the body bychelation.[35][36] This should be applied with caution as it not only remove aluminum in the body, but also othermetals such ascopper oriron.[35]
High levels of aluminum occur near mining sites. Small amounts of aluminum are released to the environment at the coal-fired power plants or incinerators. aluminum in the air is washed out by the rain or normally settles down. But, small particles of aluminum remain in the air for a long time.[28]
Acid rain is the main natural factor to move aluminum from natural sources. It is also the main reason for the effects of aluminum on the environment.[37] The main factor for the presence of aluminum insalt andfreshwater are the industrial processes that also release aluminum intoair.[38]
Aluminum 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.[39][40][41][42] Wheat has developed a tolerance to aluminum. It releasesorganic compounds that bind to harmful aluminum cations.Sorghum is thought to have the same method of tolerating aluminum.[43]
Aluminum 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.[32]
Pure (white) and impure (yellow) forms of aluminum chlorideA roll of aluminumBauxite, aluminum oreAluminum 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.
↑Dohmeier, C.; Loos, D.; Schnöckel, H. (1996). "Aluminum(I) and Gallium(I) Compounds: Syntheses, Structures, and Reactions".Angewandte Chemie International Edition.35:129–149.doi:10.1002/anie.199601291.
