Aluminium

{{About|the chemical element}} {{good article}} {{Use American English|date=June 2025}} {{Use mdy dates|date=June 2025}}  {{Infobox aluminium}}

'''Aluminium''' (the Commonwealth and preferred IUPAC name) or '''aluminum''' (North American English) is a chemical element; it has symbol '''Al''' and atomic number 13. It has a density lower than other common metals, about one-third that of steel. Aluminium has a great affinity toward oxygen, forming a protective layer of oxide on the surface when exposed to air. It visually resembles silver, both in its color and in its great ability to reflect light. It is soft, nonmagnetic, and ductile. It has one stable isotope, 27Al, which is highly abundant, making aluminium the 12th-most abundant element in the universe. The radioactivity of 26Al leads to it being used in radiometric dating.

Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it has more polarizing power, and bonds formed by aluminium have a more covalent character. The strong affinity of aluminium for oxygen leads to the common occurrence of its oxides in nature. Aluminium is found on Earth primarily in rocks in the crust, where it is the third-most abundant element after oxygen and silicon, rather than in the mantle, and virtually never as the free metal. It is obtained industrially by mining bauxite, a sedimentary rock rich in aluminium minerals.

The discovery of aluminium was announced in 1825 by Danish physicist Hans Christian Ørsted. The first industrial production of aluminium was initiated by French chemist Henri Étienne Sainte-Claire Deville in 1856. Aluminium became much more available to the public with the Hall–Héroult process developed independently by French engineer Paul Héroult and American engineer Charles Martin Hall in 1886, and the mass production of aluminium led to its extensive use in industry and everyday life. In 1954, aluminium became the most produced non-ferrous metal, surpassing copper. In the 21st century, most aluminium was consumed in transportation, engineering, construction, and packaging in the United States, Western Europe, and Japan. The standard atomic weight of aluminium is low in comparison with many other metals,{{efn|Most other metals have greater standard atomic weights: for instance, that of iron is {{val|55.845}}; copper {{val|63.546}}; lead {{val|207.2}}.{{CIAAW2021}} which has consequences for the element's properties (see below)}} giving it the low density responsible for many of its uses.

Despite its prevalence in the environment, no living thing is known to metabolize aluminium salts, but aluminium is well tolerated by plants and animals. Because of the abundance of these salts, the potential for a biological role for them is of interest, and studies are ongoing.

== Physical characteristics == === Bulk === left|thumb|Aluminium ingot [[File:Elemental Bullion.jpg|thumb|Three {{convert|1.0|lb|kg|sigfig=3}} bullion ingots of triple nine aluminium, iron, and copper etched with their scientific details. ]]Aluminium metal has an appearance ranging from silvery white to dull gray depending on its surface roughness.{{efn|The two sides of aluminium foil differ in their luster: one is shiny and the other is dull. The difference is due to the small mechanical damage on the surface of dull side arising from the technological process of aluminium foil manufacturing.<ref name="ReynoldsKitchens">{{Cite web |title=Heavy Duty Foil |url=https://www.reynoldskitchens.com/products/aluminum-foil/heavy-duty-foil/|website=Reynolds Kitchens|language=en|access-date=20 September 2020 |archive-date=23 September 2020|archive-url=https://web.archive.org/web/20200923185810/https://www.reynoldskitchens.com/products/aluminum-foil/heavy-duty-foil/ |url-status=live}}</ref> Both sides reflect similar amounts of visible light, but the shiny side reflects a far greater share of visible light specularly whereas the dull side almost exclusively diffuses light. Both sides of aluminium foil serve as good reflectors (approximately 86%) of visible light and an excellent reflector (as much as 97%) of medium and far infrared radiation.<ref name="Pozzobon">{{Cite journal |last1=Pozzobon|first1=V.|last2=Levasseur|first2=W.|last3=Do|first3=Kh.-V.|display-authors=3|last4=Palpant|first4=Bruno|last5=Perré|first5=Patrick|date=2020 |title=Household aluminum foil matte and bright side reflectivity measurements: Application to a photobioreactor light concentrator design |journal=Biotechnology Reports|language=en|volume=25|article-number=e00399|doi=10.1016/j.btre.2019.e00399|pmc=6906702|pmid=31867227 | issn=2215-017X }}</ref>}} Aluminium mirrors provides high reflectivity for light in the ultraviolet, visible (on par with silver),<ref name="Hummel-1981">{{cite journal |last1=Hummel |first1=R.E. |title=Reflectivity of silver- and aluminium-based alloys for solar reflectors |journal=Solar Energy |date=1981 |volume=27 |issue=6 |pages=449–455 |doi=10.1016/0038-092x(81)90040-2 |bibcode=1981SoEn...27..449H }}</ref> and far infrared regions.<ref>{{Cite book |last1=Hass |first1=G. |title=Physics of Thin Films - Advances in Research and Development |last2=Heaney |first2=J. B. |last3=Hunter |first3=W. R. |date=1982 |publisher=Elsevier |isbn=978-0-12-533012-1 |editor-last=Hass |editor-first=Georg |volume=12 |page=8 |chapter=Reflectance and Preparation of Front Surface Mirrors for Use at Various Angles of Incidence from the Ultraviolet to the Far Infrared |doi=10.1016/s0079-1970(13)70008-2 |editor2-last=Francombe |editor2-first=Maurice H. |editor3-last=Vossen |editor3-first=John L. }}</ref> Aluminium is also good at reflecting solar radiation, although prolonged exposure to sunlight in air can deteriorate the reflectivity of the metal;<ref name="Hummel-1981" /> this may be prevented if aluminium is anodized, which adds a protective layer of oxide on the surface.<ref>{{cite book |last1=Yerokhin |first1=A. |chapter=4 - Anodising of light alloys |date=2010 |title=Surface Engineering of Light Alloys |pages=83–109 |editor-last=Dong |editor-first=Hanshan |publisher=Woodhead Publishing |doi=10.1533/9781845699451.2.83 |isbn=978-1-84569-537-8 |last2=Khan |first2=R. H. U. }}</ref>

The density of aluminium is 2.70 g/cm3, about one-third that of steel, much lower than other commonly encountered metals, making aluminium parts easily identifiable through their lightness.{{sfn|Lide|2004|p=4-3}} Aluminium's low density compared to most other metals arises from the fact that its unit cell size is relatively large in proportion to the number of nucleons. The only lighter metals are the metals of groups 1 and 2, which, apart from beryllium and magnesium, are too reactive for structural use (and beryllium is very toxic).<ref>{{cite journal |last1=Puchta |first1=Ralph |date=2011 |title=A brighter beryllium |journal=Nature Chemistry |volume=3 |issue=5 |page=416 |bibcode=2011NatCh...3..416P |doi=10.1038/nchem.1033 |pmid=21505503 |doi-access=free}}</ref> Aluminium is not as strong or stiff as steel, but the low density makes up for this in the aerospace industry and for many other applications where light weight and relatively high strength are crucial.{{sfn|Davis|1999|pp=1–3}}

Pure aluminium is quite soft and lacking in strength. In most applications, various aluminium alloys are used instead because of their higher strength and hardness.{{sfn|Davis|1999|p=2}} The yield strength of pure aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa.<ref name="Polmear19952">{{cite book |last1=Polmear |first1=I.J. |title=Light Alloys: Metallurgy of the Light Metals |date=1995 |publisher=Butterworth-Heinemann |isbn=978-0-340-63207-9 |edition=3}}</ref> Aluminium is ductile, with a percent elongation of 50–70%,<ref name="Cardarelli 2008 p158-1632">{{Cite book |last=Cardarelli |first=François |title=Materials handbook: a concise desktop reference |date=2008 |publisher=Springer |isbn=978-1-84628-669-8 |edition=2nd |location=London |pages=158–163 |oclc=261324602}}</ref> and malleable allowing it to be easily drawn and extruded;{{sfn|Davis|1999|p=4}} it is also easily machined and cast.{{sfn|Davis|1999|p=4}}

Aluminium is an excellent thermal and electrical conductor, and the amount of aluminium required to match the same amperage in copper weighs only half as much.{{sfn|Davis|1999|pp=2–3}} Aluminium is capable of superconductivity, with a superconducting critical temperature of 1.2 kelvin and a critical magnetic field of about 100 gauss (10 milliteslas).<ref>{{cite journal |last1=Cochran |first1=J.F. |last2=Mapother |first2=D.E. |date=1958 |title=Superconducting Transition in Aluminum |journal=Physical Review |volume=111 |issue=1 |pages=132–142 |bibcode=1958PhRv..111..132C |doi=10.1103/PhysRev.111.132}}</ref> It is paramagnetic and thus essentially unaffected by static magnetic fields.{{sfn|Schmitz|2006|p=6}} However, the high electrical conductivity means that it is strongly affected by alternating magnetic fields through the induction of eddy currents.{{sfn|Schmitz|2006|p=161}}

=== Electron shell === An aluminium atom has 13 electrons with an electron configuration of {{nowrap|{{bracket|Ne}} 3s2 3p1}},{{sfn|Dean|1999|p=4.2}} with three electrons beyond a stable noble gas configuration. Accordingly, the combined first three ionization energies of aluminium are far lower than the fourth ionization energy alone.{{sfn|Dean|1999|p=4.6}} Such an electron configuration is shared with the other well-characterized members of its group, boron, gallium, indium, and thallium; it is also expected for nihonium. Aluminium can surrender its three outermost electrons in many chemical reactions (see below). The electronegativity of aluminium is 1.61 on the Pauling scale.{{sfn|Dean|1999|p=4.29}} [[File:Aluminium_Atomic_lattice.png|alt=M. Tunes & S. Pogatscher, Montanuniversität Leoben 2019 No copyrights =)|left|thumb|High-resolution STEM-HAADF micrograph of Al atoms viewed along the [001] zone axis.]] A free aluminium atom has an atomic radius of 143 pm.{{sfn|Dean|1999|p=4.30}} With the three outermost electrons removed, the radius shrinks to 39 pm for a 4-coordinated atom or 53.5 pm for a 6-coordinated atom.{{sfn|Dean|1999|p=4.30}} At standard temperature and pressure, aluminium atoms (when not affected by atoms of other elements) form a face-centered cubic crystal system bound by metallic bonding provided by atoms' outermost electrons; hence, aluminium (at these conditions) is a metal.<ref name="Enghag20082">{{cite book |last=Enghag |first=Per |url=https://books.google.com/books?id=fUmTX8yKU4gC |title=Encyclopedia of the Elements: Technical Data – History – Processing – Applications |date=2008 |publisher=John Wiley & Sons |isbn=978-3-527-61234-5 |pages=139, 819, 949 |access-date=7 December 2017 |archive-url=https://web.archive.org/web/20191225132056/https://books.google.com/books?id=fUmTX8yKU4gC |archive-date=25 December 2019 |url-status=live}}</ref> This crystal system is shared by many other metals, such as lead and copper; the size of a unit cell of aluminium is comparable to that of those other metals.<ref name="Enghag20082" /> This system, however, is not shared by the other members of its group: boron has ionization energies too high to allow metallization, thallium has a hexagonal close-packed structure, and gallium and indium have unusual structures that are not close-packed like those of aluminium and thallium. The few electrons that are available for metallic bonding in aluminium are a probable cause for it being soft with a low melting point and low electrical resistivity.{{sfn|Greenwood|Earnshaw|1997|pp=222–224}}

=== Isotopes === {{Main|Isotopes of aluminium}}

Aluminium has one stable isotope, 27Al, which comprises virtually all of the naturally-occurring element. This is common for elements with an odd atomic number.{{efn|No elements with odd atomic number have more than two stable isotopes, while even-numbered elements from oxygen to lead (atomic numbers 8 to 82) all have more than two.<ref name="IAEA">{{cite web |url=https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html |title=Livechart – Table of Nuclides – Nuclear structure and decay data sciences

|author=IAEA – Nuclear Data Section|year=2017|website=www-nds.iaea.org|publisher=International Atomic Energy Agency|access-date=31 March 2017 |archive-date=23 March 2019|archive-url=https://web.archive.org/web/20190323230752/https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html|url-status=live}}</ref> See Even and odd atomic nuclei for more details.}} It is therefore a mononuclidic element for standard atomic weight, which is determined completely by that isotope. Aluminium is useful in nuclear magnetic resonance (NMR), as its single stable isotope (though quadrupolar) has a high NMR sensitivity.{{sfn|Greenwood|Earnshaw|1997|pp=242–252}}

All other isotopes of aluminium are radioactive. The most stable of these is 26Al, with a half-life of 717,000 years. While it was present along with stable 27Al in the interstellar medium from which the Solar System formed (believed to have been produced by stellar nucleosynthesis also), no detectable amount could have survived the time since the formation of the planet. However, minute traces of 26Al are still produced from decay of argon in the atmosphere induced by ionizing radiation of cosmic rays. The ratio of 26Al to 10Be has been used for the radiodating of geological processes over 105 to 106 year time scales, in particular transport, deposition, sediment storage, burial times, and erosion.<ref>{{cite book |last1=Dickin |first1=A.P. |title=Radiogenic Isotope Geology |date=2005 |publisher=Cambridge University Press |isbn=978-0-521-53017-0 |chapter=''In situ'' Cosmogenic Isotopes |access-date=16 July 2008 |chapter-url=http://www.onafarawayday.com/Radiogenic/Ch14/Ch14-6.htm |archive-url=https://web.archive.org/web/20081206010805/http://www.onafarawayday.com/Radiogenic/Ch14/Ch14-6.htm |archive-date=6 December 2008 }}</ref> Most meteorite scientists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago.<ref>{{cite book |last1=Dodd |first1=R.T. |url=https://archive.org/details/thunderstonessho00dodd_673 |title=Thunderstones and Shooting Stars |date=1986 |publisher=Harvard University Press |isbn=978-0-674-89137-1 |pages=[https://archive.org/details/thunderstonessho00dodd_673/page/n99 89]–90 |url-access=limited}}</ref>

The other known isotopes of aluminium, with mass numbers ranging from 20 to 43, all have half-lives less than 7 minutes, as do the four detected metastable states.<ref>{{NUBASE2020}}</ref>

== Chemistry ==

Aluminium combines characteristics of pre- and post-transition metals. Since it has few available electrons for metallic bonding, like the heavier group 13 elements, it has the characteristic physical properties of a post-transition metal, with longer-than-expected interatomic distances.{{sfn|Greenwood|Earnshaw|1997|pp= 222–224}} Furthermore, as Al3+ is a small and highly charged cation, it is strongly polarizing, and bonding in aluminium compounds tends towards covalency;{{sfn|Greenwood|Earnshaw|1997|pp=224–227}} this behavior is similar to that of beryllium (Be2+), displaying an example of a diagonal relationship.{{sfn|Greenwood|Earnshaw|1997|pp=112–113}}

The underlying core of electrons under aluminium's valence shell is that of the preceding noble gas, whereas those of the heavier group 13 elements gallium, indium, thallium, and nihonium also include a filled d-subshell and in some cases a filled f-subshell. Hence, the inner electrons of aluminium shield the valence electrons almost completely, unlike those of the heavier group 13 elements. As such, aluminium is the most electropositive metal in its group, and its hydroxide is in fact more basic than that of gallium.{{sfn|Greenwood|Earnshaw|1997|pp=224–227}}{{efn|In fact, aluminium's electropositive behavior, high affinity for oxygen, and highly negative standard electrode potential are all better aligned with those of scandium, yttrium, lanthanum, and actinium, which like aluminium have three valence electrons outside a noble gas core; this series shows continuous trends whereas those of group 13 is broken by the first added d-subshell in gallium and the resulting d-block contraction and the first added f-subshell in thallium and the resulting lanthanide contraction.{{sfn|Greenwood|Earnshaw|1997|pp=224–227}}}} Aluminium also bears minor similarities to boron (a metalloid), which is in the same group: AlX3 compounds are valence isoelectronic to BX3 compounds (they have the same valence electronic structure), and both behave as Lewis acids and readily form adducts.{{sfn|King|1995|p=241}} Additionally, one of the main motifs of boron chemistry is regular icosahedral structures, and aluminium forms an important part of many icosahedral quasicrystal alloys, including the Al–Zn–Mg class.{{sfn|King|1995|pp=235–236}}

Aluminium has a high chemical affinity to oxygen, which renders it suitable for use as a reducing agent in the thermite reaction. A fine powder of aluminium reacts explosively on contact with liquid oxygen; under normal conditions, however, aluminium forms a thin oxide layer (~5 nm at room temperature)<ref>{{Cite book |last=Hatch|first=John E.|title=Aluminum: properties and physical metallurgy|date=1984 |publisher=American Society for Metals, Aluminum Association |location=Metals Park, Ohio|page=242 |oclc=759213422|isbn=978-1-61503-169-6}} </ref> that protects the metal from further corrosion by oxygen, water, or dilute acid, a process termed passivation.{{sfn|Greenwood|Earnshaw|1997|pp=224–227}}<ref name="CorrAl">{{cite book |url=https://books.google.com/books?id=NAABS5KrVDYC&pg=PA81 |title=Corrosion of Aluminium|last=Vargel|first=Christian|date=2004 |publisher=Elsevier|isbn=978-0-08-044495-6|orig-date=French edition published 1999 |archive-url=https://web.archive.org/web/20160521212331/https://books.google.com/books?id=NAABS5KrVDYC&pg=PA81|archive-date=21 May 2016|url-status=live}} </ref> Aluminium is not attacked by oxidizing acids because of its passivation. This allows aluminium to be used to store reagents such as nitric acid, concentrated sulfuric acid, and some organic acids.<ref name="Ullmann">{{cite book |last1=Frank|first1=W.B.|title=Ullmann's Encyclopedia of Industrial Chemistry|title-link=Ullmann's Encyclopedia of Industrial Chemistry|date=2009 |publisher=Wiley-VCH|isbn=978-3-527-30673-2|chapter=Aluminum|doi=10.1002/14356007.a01_459.pub2}}</ref>

In hot, concentrated hydrochloric acid, aluminium reacts with water through evolution of hydrogen, and it reacts in aqueous sodium or potassium hydroxide at room temperature to form aluminates; protective passivation under these conditions is negligible.<ref name="Beal1999">{{cite book|url=https://books.google.com/books?id=Askwi3lXdlcC&pg=PA90|title=Engine Coolant Testing: Fourth Volume|last=Beal|first=Roy E.|year=1999|publisher=ASTM International|isbn=978-0-8031-2610-7|page=90|archive-url=https://web.archive.org/web/20160424071051/https://books.google.com/books?id=Askwi3lXdlcC&pg=PA90|archive-date=24 April 2016|url-status=live}}</ref> Aqua regia also dissolves aluminium.<ref name="Ullmann" /> Aluminium is also corroded by dissolved chlorides,<ref>{{Cite journal |last1=Xhanari |first1=Klodian |last2=Finšgar |first2=Matjaž |date=December 2019 |title=Organic corrosion inhibitors for aluminum and its alloys in chloride and alkaline solutions: A review |journal=Arabian Journal of Chemistry |language=en |volume=12 |issue=8 |page=4648 |doi=10.1016/j.arabjc.2016.08.009|bibcode=2019ArJC...12.4646X |doi-access=free }}</ref> such as common sodium chloride. The oxide layer on aluminium is also destroyed by contact with mercury due to amalgamation or by contact with salts of some electropositive metals.{{sfn|Greenwood|Earnshaw|1997|pp=224–227}} As such, the strongest aluminium alloys are less corrosion-resistant due to galvanic reactions with alloyed copper,<ref name="Polmear1995">{{cite book |last1=Polmear |first1=I.J. |title=Light Alloys: Metallurgy of the Light Metals |date=1995 |publisher=Butterworth-Heinemann |isbn=978-0-340-63207-9 |edition=3}} </ref> and aluminium's corrosion resistance is greatly reduced by aqueous salts, particularly in the presence of dissimilar metals.{{sfn|Greenwood|Earnshaw|1997|pp= 222–224}}

Aluminium reacts with most nonmetals upon heating, forming compounds such as aluminium nitride (AlN), aluminium sulfide (Al2S3), and the aluminium halides (AlX3). It also forms a wide range of intermetallic compounds involving metals from every group on the periodic table.{{sfn|Greenwood|Earnshaw|1997|pp=224–227}}

=== Inorganic compounds ===

The vast majority of aluminium compounds, including all aluminium-containing minerals and all commercially significant aluminium compounds, feature aluminium in the oxidation state 3+. The coordination number of such compounds varies, but generally Al3+ is either six- or four-coordinate. Almost all compounds of aluminium(III) are colorless.{{sfn|Greenwood|Earnshaw|1997|pp=224–227}}

thumb|upright=1.0|right|Aluminium hydrolysis as a function of pH. Coordinated water molecules are omitted.<ref>*{{cite book |last1=Baes|first1=C. F. |last2=Mesmer|first2=R. E. |title=The Hydrolysis of Cations|year=1986|orig-date=1976 |publisher=Robert E. Krieger|isbn=978-0-89874-892-5}}</ref> In aqueous solution, Al3+ exists as the hexa-aqua cation [Al(H2O)6]3+, which has an approximate Ka of 10−5.{{sfn|Greenwood|Earnshaw|1997|pp=242–252}} Such solutions are acidic because this cation can act as a proton donor and progressively hydrolyze until a precipitate of aluminium hydroxide, Al(OH)3, forms. This is useful for clarification of water, since the precipitate nucleates on suspended particles in the water, hence removing them. Increasing the pH even further leads to the hydroxide dissolving again as aluminate, [Al(H2O)2(OH)4]−, is formed.

Aluminium hydroxide forms both salts and aluminates and dissolves in acid and alkali, as well as on fusion with acidic and basic oxides.{{sfn|Greenwood|Earnshaw|1997|pp=224–227}} This behavior of Al(OH)3 is termed amphoterism and is characteristic of weakly basic cations that form insoluble hydroxides and whose hydrated species can also donate their protons. One effect of this is that aluminium salts with weak acids are hydrolyzed in water to the aquated hydroxide and the corresponding nonmetal hydride: for example, aluminium sulfide yields hydrogen sulfide. However, some salts like aluminium carbonate exist in aqueous solution but are unstable as such. Only incomplete hydrolysis takes place for salts with strong acids, such as the halides, nitrate, and sulfate. For similar reasons, anhydrous aluminium salts cannot be made by heating their "hydrates": hydrated aluminium chloride is in fact not AlCl3·6H2O but [Al(H2O)6]Cl3, and the Al–O bonds are so strong that heating is not sufficient to break them and form Al–Cl bonds. This reaction is observed instead:{{sfn|Greenwood|Earnshaw|1997|pp=224–227}}

:2[Al(H2O)6]Cl3 {{overunderset|→|heat| }} Al2O3 + 6 HCl + 9 H2O

All four trihalides are well known. Unlike the structures of the three heavier trihalides, aluminium fluoride (AlF3) features six-coordinate aluminium, which explains its involatility and insolubility as well as high heat of formation. Each aluminium atom is surrounded by six fluorine atoms in a distorted octahedral arrangement, with each fluorine atom being shared between the corners of two octahedra. Such {AlF6} units also exist in complex fluorides such as cryolite, Na3AlF6.{{efn|These should not be considered as [AlF6]3− complex anions as the Al–F bonds are not significantly different in type from the other M–F bonds.{{sfn|Greenwood|Earnshaw|1997|pp=233–237}}}} AlF3 melts at {{convert|1290|°C|0|abbr=on}} and is made by reaction of aluminium oxide with hydrogen fluoride gas at {{convert|700|°C|-2|abbr=on}}.{{sfn|Greenwood|Earnshaw|1997|pp=233–237}}

With heavier halides, the coordination numbers are lower. The other trihalides are dimeric or polymeric with tetrahedral four-coordinate aluminium centers.{{efn|Such differences in coordination between the fluorides and heavier halides are not unusual, occurring in SnIV and BiIII, for example; even bigger differences occur between CO2 and SiO2.{{sfn|Greenwood|Earnshaw|1997|pp=233–237}}}} Aluminium trichloride (AlCl3) has a layered polymeric structure below its melting point of {{convert|192.4|°C|0|abbr=on}} but transforms on melting to Al2Cl6 dimers. At higher temperatures those increasingly dissociate into trigonal planar AlCl3 monomers similar to the structure of BCl3. Aluminium tribromide and aluminium triiodide form Al2X6 dimers in all three phases and hence do not show such significant changes of properties upon phase change.{{sfn|Greenwood|Earnshaw|1997|pp=233–237}} These materials are prepared by treating aluminium with the halogen. The aluminium trihalides form many addition compounds or complexes. Their Lewis acidic nature makes them useful as catalysts for the Friedel–Crafts reactions. Aluminium trichloride has major industrial uses involving this reaction, such as in the manufacture of anthraquinones and styrene. Aluminium trichloride is also often used as the precursor for many other aluminium compounds and as a reagent for converting nonmetal fluorides into the corresponding chlorides (a transhalogenation reaction).{{sfn|Greenwood|Earnshaw|1997|pp=233–237}}

Aluminium forms one stable oxide with the chemical formula Al2O3, commonly called alumina.<ref>{{Cite book |url=https://books.google.com/books?id=MYAABAAAQBAJ&q=Aluminium+forms+one+stable+oxide,+known+by+its+mineral+name+corundum&pg=PA14|title=Pigment Compendium |last1=Eastaugh|first1=Nicholas|last2=Walsh|first2=Valentine|last3=Chaplin|first3=Tracey|last4=Siddall|first4=Ruth|date=2008 |publisher=Routledge|isbn=978-1-136-37393-0|language=en|access-date=1 October 2020 |archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415083327/https://books.google.com/books?id=MYAABAAAQBAJ&q=Aluminium+forms+one+stable+oxide,+known+by+its+mineral+name+corundum&pg=PA14|url-status=live}} </ref> It can be found in nature in the mineral corundum, the α-alumina phase.<ref>{{Cite book |url=https://books.google.com/books?id=X2NZAAAAYAAJ&q=Aluminium+forms+one+stable+oxide,+known+by+its+mineral+name+corundum&pg=PA718 |title=A treatise on chemistry|last1=Roscoe|first1=Henry Enfield|last2=Schorlemmer|first2=Carl|date=1913 |publisher=Macmillan|language=en|access-date=1 October 2020 |archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415111928/https://books.google.com/books?id=X2NZAAAAYAAJ&q=Aluminium+forms+one+stable+oxide,+known+by+its+mineral+name+corundum&pg=PA718|url-status=live}} </ref> There is also a γ-alumina phase.{{sfn|Greenwood|Earnshaw|1997|pp=242–252}} Its crystalline form, corundum, is very hard (Mohs hardness 9), has a high melting point of {{convert|2045|°C|0|abbr=on}}, has very low volatility, is chemically inert, and is a good electrical insulator. It is often used in abrasives (such as sandpaper) as a refractory material and in ceramics. It is also the starting material for the electrolytic production of aluminium. Sapphire and ruby are impure corundum contaminated with trace amounts of other metals.{{sfn|Greenwood|Earnshaw|1997|pp=242–252}}

The two main oxide-hydroxides, AlO(OH), are boehmite and diaspore. There are three main trihydroxides: bayerite, gibbsite, and nordstrandite, which differ in their crystalline structure (polymorphs). Many other intermediate and related structures are also known.{{sfn|Greenwood|Earnshaw|1997|pp=242–252}} Most of these Al-O-OH systems are produced from ores by a variety of wet processes using acid and bases. Heating the hydroxides leads to the formation of corundum. These materials are of central importance to the production of aluminium and are themselves extremely useful. Some mixed oxide phases are also very useful, such as spinel (MgAl2O4), Na-β-alumina (NaAl11O17), and tricalcium aluminate (Ca3Al2O6), an important mineral phase in Portland cement.{{sfn|Greenwood|Earnshaw|1997|pp=242–252}}

The only stable chalcogenides under normal conditions are aluminium sulfide (Al2S3), selenide (Al2Se3), and telluride (Al2Te3). All three are prepared by direct reaction of their elements at about {{convert|1000|°C|-2|abbr=on}} and quickly hydrolyze completely in water to yield aluminium hydroxide and the respective hydrogen chalcogenide. As aluminium is a small atom relative to these chalcogens, these have four-coordinate tetrahedral aluminium with various polymorphs having structures related to wurtzite, with two-thirds of the possible metal sites occupied either in an orderly (α) or random (β) fashion. The sulfide also has a γ form related to γ-alumina and an unusual high-temperature hexagonal form where half the aluminium atoms have tetrahedral four-coordination and the other half have trigonal bipyramidal five-coordination.{{sfn|Greenwood|Earnshaw|1997|pp=252–257}}

Four pnictides – aluminium nitride (AlN), aluminium phosphide (AlP), aluminium arsenide (AlAs), and aluminium antimonide (AlSb) – are known. They are all III-V semiconductors isoelectronic to silicon and germanium, all of which but AlN have the zinc blende structure. All four can be made by high-temperature (and possibly high-pressure) direct reaction of their component elements.{{sfn|Greenwood|Earnshaw|1997|pp=252–257}} <!-- Aluminium carbide (Al4C3) is made by heating a mixture of the elements above {{convert|1000|°C|-2|abbr=on}}. The pale yellow crystals consist of tetrahedral aluminium centers. It reacts with water or dilute acids to give methane. The acetylide, Al2(C2)3, is made by passing acetylene over heated aluminium.

Aluminium nitride (AlN) is the only nitride known for aluminium. Unlike the oxides, it features tetrahedral Al centers. It can be made from the elements at {{convert|800|°C|-2|abbr=on}}. It is air-stable material with a usefully high thermal conductivity. Aluminium phosphide (AlP) is made similarly; it hydrolyses to give phosphine:

: AlP + 3 H2O → Al(OH)3 + PH3-->

Aluminium alloys well with most other metals (with the exception of most alkali metals and group 13 metals) and over 150 intermetallics with other metals are known. Preparation involves heating fixed metals together in certain proportions, followed by gradual cooling and annealing. Bonding in them is predominantly metallic and the crystal structure primarily depends on efficiency of packing.<ref>{{Cite book |last=Downs|first=A. J. |url=https://books.google.com/books?id=v-04Kn758yIC&q=intermetallic+aluminium&pg=PA218 |title=Chemistry of Aluminium, Gallium, Indium and Thallium|date=1993 |publisher=Springer Science & Business Media|isbn=978-0-7514-0103-5|page=218|language=en|access-date=1 October 2020 |archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415115039/https://books.google.com/books?id=v-04Kn758yIC&q=intermetallic+aluminium&pg=PA218|url-status=live}}</ref>

There are few compounds with lower oxidation states. Some are aluminium(I) compounds: AlF, AlCl, AlBr, and {{serif|AlI}} all exist in the gaseous phase when the respective trihalide is heated with aluminium, and at cryogenic temperatures.{{sfn|Greenwood|Earnshaw|1997|pp=233–237}} A stable derivative of aluminium monoiodide is the cyclic adduct formed with triethylamine, Al4I4(NEt3)4. Al2O and Al2S also exist but are very unstable.<ref name="al1">{{cite journal |last1=Dohmeier |first1=C. |last2=Loos |first2=D. |last3=Schnöckel |first3=H. |date=1996 |title=Aluminum(I) and Gallium(I) Compounds: Syntheses, Structures, and Reactions |journal=Angewandte Chemie International Edition |volume=35 |issue=2 |pages=129–149 |doi=10.1002/anie.199601291 }}</ref> Very simple aluminium(II) compounds are invoked or observed in the reactions of Al metal with oxidants. For example, aluminium monoxide, AlO, has been detected in the gas phase after explosion<ref>{{cite journal |last1=Tyte |first1=D.C. |date=1964 |title=Red (B2Π–A2σ) Band System of Aluminium Monoxide |journal=Nature |volume=202 |issue=4930 |pages=383–384 |bibcode=1964Natur.202..383T |doi=10.1038/202383a0 }}</ref> and in stellar absorption spectra.<ref>{{cite journal |last1=Merrill |first1=P.W. |last2=Deutsch |first2=A.J. |last3=Keenan |first3=P.C. |date=1962 |title=Absorption Spectra of M-Type Mira Variables |journal=The Astrophysical Journal |volume=136 |page=21 |bibcode=1962ApJ...136...21M |doi=10.1086/147348 }}</ref> More thoroughly investigated are compounds of the formula R4Al2 which contain an Al–Al bond and where R is a large organic ligand.<ref>{{Cite book |last=Uhl |first=W. |title=Advances in Organometallic Chemistry Volume 51 |chapter=Organoelement Compounds Possessing Al–Al, Ga–Ga, In–In, and Tl–Tl Single Bonds |date=2004 |volume=51 |pages=53–108 |doi=10.1016/S0065-3055(03)51002-4 |isbn=978-0-12-031151-4 }}</ref>

=== Organoaluminium compounds and related hydrides ===

[[File:Trimethylaluminium-from-xtal-3D-bs-17-25.png|thumb|upright=1.0|Structure of trimethylaluminium, a compound that features five-coordinate carbon.]]

A variety of compounds of empirical formula AlR3 and AlR1.5Cl1.5 exist.<ref>{{cite book |last1=Elschenbroich |first1=C. |date=2006 |title=Organometallics |publisher=Wiley-VCH |isbn=978-3-527-29390-2 }}</ref> The aluminium trialkyls and triaryls are either reactive, volatile, and colorless liquids or low-melting solids. They catch fire spontaneously in air and react with water, thus necessitating precautions when handling them. They often form dimers, unlike their boron analogues, but this tendency diminishes for branched-chain alkyls (e.g. Pr''i'', Bu''i'', Me3CCH2).

For example, triisobutylaluminium exists as an equilibrium mixture of the monomer and dimer.{{sfn|Greenwood|Earnshaw|1997|pp=257–67}}<ref>{{cite journal|title=The monomer-dimer equilibria of liquid aluminum alkyls|year=1970|last1=Smith|first1=Martin B.|journal=Journal of Organometallic Chemistry|pages=273–281|issue=2|doi=10.1016/S0022-328X(00)86043-X|volume=22}}</ref> These dimers, such as trimethylaluminium (Al2Me6), usually feature tetrahedral Al centers formed by dimerization with some alkyl group bridging between both aluminium atoms. They are hard acids and react readily with ligands, forming adducts. In industry, they are mostly used in alkene insertion reactions, as discovered by Karl Ziegler, most importantly in "growth reactions" that form long-chain unbranched primary alkenes and alcohols, and in the low-pressure polymerization of ethene and propene. There are also some heterocyclic and cluster organoaluminium compounds involving Al–N bonds.{{sfn|Greenwood|Earnshaw|1997|pp=257–67}}

The industrially most important aluminium hydride is lithium aluminium hydride (LiAlH4), which is used as a reducing agent in organic chemistry. It can be produced from lithium hydride and aluminium trichloride.{{sfn|Greenwood|Earnshaw|1997|pp=227–232}} The simplest hydride, aluminium hydride or alane, is not as important. It is a polymer with the formula (AlH3)''n'', which is in contrast to the corresponding boron hydride that is a dimer with the formula (BH3)2.{{sfn|Greenwood|Earnshaw|1997|pp=227–232}}

== Natural occurrence ==

=== Space ===

Aluminium's per-particle abundance in the Solar System is 3.15 ppm (parts per million).<ref name="Lodders">{{cite journal |last1=Lodders |first1=Katharina |title=Solar System Abundances and Condensation Temperatures of the Elements |journal=The Astrophysical Journal |date=10 July 2003 |volume=591 |issue=2 |pages=1220–1247 |doi=10.1086/375492 |bibcode=2003ApJ...591.1220L }}</ref>{{efn|Abundances in the source are listed relative to silicon rather than in per-particle notation. The sum of all elements per 106 parts of silicon is 2.6682{{e|10}} parts; aluminium comprises 8.410{{e|4}} parts.}} It is the twelfth most abundant of all elements and third most abundant among the elements that have odd atomic numbers, after hydrogen and nitrogen.<ref name="Lodders" /> The only stable isotope of aluminium, 27Al, is the eighteenth most abundant nucleus in the universe. It is created almost entirely after fusion of carbon in massive stars that will later become Type II supernovas: this fusion creates 26Mg, which upon capturing free protons and neutrons, becomes aluminium. Some smaller quantities of 27Al are created in hydrogen burning shells of evolved stars, where 26Mg can capture free protons.<ref name="Clayton" />

Essentially all aluminium now in existence is 27Al. 26Al was present in the early Solar System with abundance of 0.005% relative to 27Al but its half-life of 728,000 years is too short for any original nuclei to survive; 26Al is therefore extinct.<ref name="Clayton">{{Cite book|last=Clayton|first=D.|title=Handbook of Isotopes in the Cosmos: Hydrogen to Gallium |date=2003|publisher=Cambridge University Press|location=Leiden|pages=129–137|oclc=609856530|isbn=978-0-511-67305-4}}</ref> Unlike for 27Al, hydrogen burning is the primary source of 26Al, with the nuclide emerging after a nucleus of 25Mg catches a free proton. However, the trace quantities of 26Al that do exist are the most common gamma ray emitter in the interstellar gas;<ref name="Clayton" /> if the original 26Al were still present, gamma ray maps of the Milky Way would be brighter.<ref name="Clayton" />

=== Earth ===

[[File:Bauxite hérault.JPG|thumb|Bauxite, a major aluminium ore. The red-brown color is due to the presence of iron oxide minerals.]]

Overall, the Earth is about 1.59% aluminium by mass (seventh in abundance by mass).<ref name="mit1">William F McDonough [https://web.archive.org/web/20110928074153/http://quake.mit.edu/hilstgroup/CoreMantle/EarthCompo.pdf The composition of the Earth]. quake.mit.edu, archived by the Internet Archive Wayback Machine.</ref> Aluminium occurs in greater proportion in the Earth's crust than in the universe at large. This is because aluminium easily forms the oxide and becomes bound into rocks and stays in the Earth's crust, while less reactive metals sink to the core.<ref name="Clayton" /> In the Earth's crust, aluminium is the most abundant metallic element (8.23% by mass<ref name="Cardarelli 2008 p158-163">{{Cite book |last=Cardarelli |first=François |title=Materials handbook: a concise desktop reference |date=2008 |publisher=Springer |isbn=978-1-84628-669-8 |edition=2nd |location=London |pages=158–163 |oclc=261324602}} </ref>) and the third most abundant of all elements (after oxygen and silicon).{{sfn|Greenwood|Earnshaw|1997|pp=217–219}} A large number of silicates in the Earth's crust contain aluminium.<ref name="WadeBanister2016">{{cite book |last1=Wade|first1=K.|last2=Banister|first2=A.J.|title=The Chemistry of Aluminium, Gallium, Indium and Thallium: Comprehensive Inorganic Chemistry |url=https://books.google.com/books?id=QwNPDAAAQBAJ&pg=PA1049|year=2016 |publisher=Elsevier|isbn=978-1-4831-5322-3|page=1049|access-date=17 June 2018 |archive-date=30 November 2019|archive-url=https://web.archive.org/web/20191130020257/https://books.google.com/books?id=QwNPDAAAQBAJ&pg=PA1049|url-status=live}}</ref> In contrast, the Earth's mantle is only 2.38% aluminium by mass.<ref>{{cite book |last1=Palme|first1=H.|last2=O'Neill|first2=Hugh St. C.|title=The Mantle and Core |editor-last=Carlson|editor-first=Richard W.|year=2005|publisher=Elseiver |chapter-url=https://www.geol.umd.edu/~mcdonoug/KITP%20Website%20for%20Bill/papers/Earth_Models/3.1%20Palme%20&%20O'Neill%20Primative%20mantle%20(1).pdf|page=14 |access-date=11 June 2021|chapter=Cosmochemical Estimates of Mantle Composition |archive-date=3 April 2021|archive-url=https://web.archive.org/web/20210403101355/https://www.geol.umd.edu/~mcdonoug/KITP%20Website%20for%20Bill/papers/Earth_Models/3.1%20Palme%20%26%20O%27Neill%20Primative%20mantle%20%281%29.pdf|url-status=live}}</ref> Aluminium also occurs in seawater at a concentration of 0.41 μg/kg.<ref>{{cite journal | doi=10.3389/fmars.2020.00468 | doi-access=free | title=A First Global Oceanic Compilation of Observational Dissolved Aluminum Data with Regional Statistical Data Treatment | date=2020 | last1=Menzel Barraqueta | first1=Jan-Lukas | last2=Samanta | first2=Saumik | last3=Achterberg | first3=Eric P. | last4=Bowie | first4=Andrew R. | last5=Croot | first5=Peter | last6=Cloete | first6=Ryan | last7=De Jongh | first7=Tara | last8=Gelado-Caballero | first8=Maria D. | last9=Klar | first9=Jessica K. | last10=Middag | first10=Rob | last11=Loock | first11=Jean C. | last12=Remenyi | first12=Tomas A. | last13=Wenzel | first13=Bernhard | last14=Roychoudhury | first14=Alakendra N. | journal=Frontiers in Marine Science | volume=7 | article-number=468 | bibcode=2020FrMaS...7..468M | hdl=10553/74194 | hdl-access=free }}</ref>

Because of its strong affinity for oxygen, aluminium is almost never found in the elemental state; instead it is found in oxides or silicates. Feldspars, the most common group of minerals in the Earth's crust, are aluminosilicates. Aluminium also occurs in the minerals beryl, cryolite, garnet, spinel, and turquoise.<ref>{{Cite book|url=https://books.google.com/books?id=v-04Kn758yIC&pg=PA17|title=Chemistry of Aluminium, Gallium, Indium and Thallium|last=Downs|first=A.J.|date=1993|publisher=Springer Science & Business Media|isbn=978-0-7514-0103-5|language=en|access-date=14 June 2017|archive-date=25 July 2020|archive-url=https://web.archive.org/web/20200725044500/https://books.google.com/books?id=v-04Kn758yIC&pg=PA17|url-status=live}}</ref> Impurities in alumina yield gemstones: for example, chromium yields ruby and iron yields sapphire.<ref name="KotzTreichel2012">{{cite book|url=https://books.google.com/books?id=eUwJAAAAQBAJ&pg=PA300|title=Chemistry and Chemical Reactivity|last1=Kotz|first1=John C.|last2=Treichel|first2=Paul M.|last3=Townsend|first3=John|publisher=Cengage Learning|year=2012|isbn=978-1-133-42007-1|page=300|access-date=17 June 2018|archive-date=22 December 2019|archive-url=https://web.archive.org/web/20191222050939/https://books.google.com/books?id=eUwJAAAAQBAJ&pg=PA300|url-status=live}}</ref> Native aluminium metal is extremely rare and can only be found as a minor phase in low oxygen fugacity environments, such as the interiors of certain volcanoes.<ref>{{cite web|url=http://webmineral.com/data/Aluminum.shtml|title=Aluminum Mineral Data|last1=Barthelmy|first1=D.|website=Mineralogy Database|archive-url=https://web.archive.org/web/20080704001129/http://webmineral.com/data/Aluminum.shtml|archive-date=4 July 2008|url-status=live|access-date=9 July 2008}}</ref> Native aluminium has been reported in cold seeps in the northeastern continental slope of the South China Sea. It is possible that these deposits resulted from bacterial reduction of tetrahydroxoaluminate Al(OH)4−.<ref name="Chen 2011">{{cite journal|last1=Chen|first1=Z.|last2=Huang|first2=Chi-Yue|last3=Zhao|first3=Meixun|last4=Yan|first4=Wen|last5=Chien|first5=Chih-Wei|last6=Chen|first6=Muhong|last7=Yang|first7=Huaping|last8=Machiyama|first8=Hideaki|last9=Lin|first9=Saulwood|date=2011|title=Characteristics and possible origin of native aluminum in cold seep sediments from the northeastern South China Sea|journal=Journal of Asian Earth Sciences|volume=40|issue=1|pages=363–370|bibcode=2011JAESc..40..363C|doi=10.1016/j.jseaes.2010.06.006}}</ref>

Although aluminium is a common and widespread element, not all aluminium minerals are economically viable sources of the metal. Almost all metallic aluminium is produced from the ore bauxite (AlO''x''(OH)3–2''x''). Bauxite occurs as a weathering product of low iron and silica bedrock in tropical climatic conditions.<ref>{{cite book|title=The Geology of Ore Deposits|last1=Guilbert|first1=J.F.|last2=Park|first2=C.F.|date=1986|publisher=W.H. Freeman|isbn=978-0-7167-1456-9|pages=774–795}}</ref> In 2017, most bauxite was mined in Australia, China, Guinea, and India.<ref>{{cite web |author=United States Geological Survey |title=Bauxite and alumina |year=2018 |url=https://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2018-bauxi.pdf |access-date=17 June 2018 |series=Mineral Commodities Summaries |archive-date=11 March 2018 |archive-url=https://web.archive.org/web/20180311202117/https://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2018-bauxi.pdf |url-status=live }}</ref>

== History ==

[[File:Friedrich_W%C3%B6hler_Litho.jpg|thumb|upright=0.75|Friedrich Wöhler, the chemist who first thoroughly described metallic elemental aluminium]]

The history of aluminium has been shaped by usage of alum. The first written record of alum, made by Greek historian Herodotus, dates back to the 5th century BCE.{{sfn|Drozdov|2007|p=12}} The ancients are known to have used alum as a dyeing mordant and for city defense as a fire-resistant coating for wood.{{sfn|Drozdov|2007|pp=12-14}} After the Crusades, alum, an indispensable good in the European fabric industry,<ref name="ClaphamPower1941">{{cite book|last1=Clapham|first1=John Harold|last2=Power|first2=Eileen Edna|title=The Cambridge Economic History of Europe: From the Decline of the Roman Empire |volume=5 |url=https://books.google.com/books?id=gBw9AAAAIAAJ&pg=PA682|orig-date=1941 |date=1977 |publisher=Cambridge University Press |isbn=0-521-08710-4 |page=207}}</ref> was a subject of international commerce;{{sfn|Drozdov|2007|p=16}} it was imported to Europe from the eastern Mediterranean until the mid-15th century.<ref>{{Cite book|title=The papacy and the Levant: 1204-1571. 1 The thirteenth and fourteenth centuries|last=Setton|first=Kenneth M.|date=1976|publisher=American Philosophical Society|isbn=978-0-87169-127-9|oclc=165383496}}</ref>

The nature of alum remained unknown until Swiss physician Paracelsus suggested alum was a salt of an earth of alum around 1530.{{sfn|Drozdov|2007|p=25}} German doctor and chemist Andreas Libavius experimentally confirmed this in 1595.<ref name="Weeks1968">{{cite book|last=Weeks|first=Mary Elvira|title=Discovery of the elements|url=https://books.google.com/books?id=s6kPAQAAMAAJ|year=1968|volume=1|edition=7|publisher=Journal of chemical education|page=187|isbn=978-0-608-30017-7}}</ref> German chemist Friedrich Hoffmann announced his belief that the base of alum was a distinct earth in 1722.{{sfn|Richards|1896|p=2}} German chemist Andreas Sigismund Marggraf synthesized alumina in 1754 by boiling clay in sulfuric acid and subsequently adding potash.{{sfn|Richards|1896|p=2}}

Attempts to produce aluminium date back to 1760.{{sfn|Richards|1896|p=3}} The first successful attempt, however, was completed 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 to tin.<ref>{{cite conference|last1=Örsted|first1=H. C.|date=1825|title=Oversigt over det Kongelige Danske Videnskabernes Selskabs Forhanlingar og dets Medlemmerz Arbeider, fra 31 Mai 1824 til 31 Mai 1825|trans-title=Overview of the Royal Danish Science Society's Proceedings and the Work of its Members, from 31 May 1824 to 31 May 1825|url=https://babel.hathitrust.org/cgi/pt?id=osu.32435054254693&view=1up&seq=17|language=da|pages=15–16|conference=|access-date=27 February 2020|archive-date=16 March 2020|archive-url=https://web.archive.org/web/20200316113549/https://babel.hathitrust.org/cgi/pt?id=osu.32435054254693&view=1up&seq=17|url-status=live}}</ref><ref name="(København)1827">{{cite book|url=https://books.google.com/books?id=L2BFAAAAcAAJ&pg=PR25|title=Det Kongelige Danske Videnskabernes Selskabs philosophiske og historiske afhandlinger|author=Royal Danish Academy of Sciences and Letters|author-link=Royal Danish Academy of Sciences and Letters|publisher=Popp|year=1827|pages=xxv–xxvi|language=da|trans-title=The philosophical and historical dissertations of the Royal Danish Science Society|access-date=11 March 2016|archive-date=24 March 2017|archive-url=https://web.archive.org/web/20170324064522/https://books.google.com/books?id=L2BFAAAAcAAJ&pg=PR25|url-status=live}}</ref><ref name="woehler">{{cite journal |last1=Wöhler |first1=F. |title=Ueber das Aluminium |journal=Annalen der Physik |date=January 1827 |volume=87 |issue=9 |pages=146–161 |doi=10.1002/andp.18270870912 |hdl=2027/uc1.b4433551?urlappend=%3Bseq=162%3Bownerid=9007199264773682-180 }}</ref> He presented his results and demonstrated a sample of the new metal in 1825.{{sfn|Drozdov|2007|p=36}}<ref name="FontaniCosta2014">{{cite book|url=https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA30|title=The Lost Elements: The Periodic Table's Shadow Side|last1=Fontani|first1=Marco|last2=Costa|first2=Mariagrazia|last3=Orna|first3=Mary Virginia|publisher=Oxford University Press|year=2014|isbn=978-0-19-938334-4|page=30}}</ref> In 1827, German chemist Friedrich Wöhler repeated Ørsted's experiments but did not identify any aluminium.<ref name="Venetski">{{cite journal|last1=Venetski|first1=S.|date=1969|title='Silver' from clay|journal=Metallurgist|volume=13|issue=7|pages=451–453|doi=10.1007/BF00741130 }}</ref> (The reason for this inconsistency was only discovered in 1921.){{sfn|Drozdov|2007|p=38}} He conducted a similar experiment in the same year by mixing anhydrous aluminium chloride with potassium (the Wöhler process) and produced a powder of aluminium.<ref name="woehler" /> In 1845, he was able to produce small pieces of the metal and described some physical properties of this metal.{{sfn|Drozdov|2007|p=38}} For many years thereafter, Wöhler was credited as the discoverer of aluminium.<ref name="Holmes1936">{{Cite journal|last=Holmes|first=Harry N.|date=1936|title=Fifty Years of Industrial Aluminum|journal=The Scientific Monthly|volume=42|issue=3|pages=236–239|jstor=15938|bibcode=1936SciMo..42..236H}}</ref>

As Wöhler's method could not yield great quantities of aluminium, the metal remained rare; its cost exceeded that of gold.<ref name="Venetski" /> The first industrial production of aluminium was established in 1856 by French chemist Henri Étienne Sainte-Claire Deville and companions.{{sfn|Drozdov|2007|p=39}} Sainte-Claire Deville had discovered that aluminium trichloride could be reduced by sodium, which was more convenient and less expensive than potassium, which Wöhler had used.<ref>{{cite book |last=Sainte-Claire Deville|first=H.É.|date=1859|title=De l'aluminium, ses propriétés, sa fabrication |url=https://books.google.com/books?id=rCoKAAAAIAAJ |publisher=Mallet-Bachelier|location=Paris|url-status=live |archive-url=https://web.archive.org/web/20160430001812/https://books.google.com/books?id=rCoKAAAAIAAJ|archive-date=30 April 2016}}</ref> Even then, aluminium was still not of great purity and produced aluminium differed in properties by sample.{{sfn|Drozdov|2007|p=46}} Because of its electricity-conducting capacity, aluminium was used as the cap of the Washington Monument, completed in 1885, the tallest building in the world at the time. The non-corroding metal cap was intended to serve as a lightning rod peak.

The first industrial large-scale production method was independently developed in 1886 by French engineer Paul Héroult and American engineer Charles Martin Hall; it is now known as the Hall–Héroult process.{{sfn|Drozdov|2007|pp=55–61}} The Hall–Héroult process converts alumina into metal. Austrian chemist Carl Joseph Bayer discovered a way of purifying bauxite to yield alumina, now known as the Bayer process, in 1889.{{sfn|Drozdov|2007|p=74}} Modern production of aluminium is based on the Bayer and Hall–Héroult processes.<ref name="aluminiumleader">{{Cite web |url=https://aluminiumleader.com/history/industry_history/|title=Aluminium history|website=All about aluminium|access-date=7 November 2017 |archive-date=7 November 2017|archive-url=https://web.archive.org/web/20171107222100/https://aluminiumleader.com/history/industry_history/|url-status=live}}</ref>

As large-scale production caused aluminium prices to drop, the metal became widely used in jewelry, eyeglass frames, optical instruments, tableware, and foil, and other everyday items in the 1890s and early 20th century. Aluminium's ability to form hard yet light alloys with other metals provided the metal with many uses at the time.{{sfn|Drozdov|2007|pp=64–69}} During World War I, major governments demanded large shipments of aluminium for light strong airframes;<ref>{{cite book |last=Ingulstad|first=Mats|year=2012 |chapter='We Want Aluminum, No Excuses': Business-Government Relations in the American Aluminum Industry, 1917–1957|pages=33–68 |title=From Warfare to Welfare: Business-Government Relations in the Aluminium Industry |chapter-url=https://books.google.com/books?id=TFS6NAEACAAJ |editor1-first=Mats|editor1-last=Ingulstad|editor2-first=Hans Otto|editor2-last=Frøland |publisher=Tapir Academic Press|isbn=978-82-321-0049-1|access-date=7 May 2020 |archive-date=25 July 2020|archive-url=https://web.archive.org/web/20200725055556/https://books.google.com/books?id=TFS6NAEACAAJ|url-status=live}} </ref> during World War II, demand by major governments for aviation was even higher.<ref name="Seldes2009">{{cite book |last=Seldes|first=George|url=https://archive.org/stream/FactsAndFascism/FactsandFascism_djvu.txt|title=Facts and Fascism|publisher=In Fact, Inc.|year=1943|edition=5|page=261|author-link=George Seldes}}</ref><ref name="Thorsheim2015">{{cite book|last=Thorsheim|first=Peter|url=https://books.google.com/books?id=uUlLCgAAQBAJ&pg=PA66|title=Waste into Weapons|publisher=Cambridge University Press|year=2015|isbn=978-1-107-09935-7|pages=66–69|access-date=7 January 2021|archive-date=6 April 2020|archive-url=https://web.archive.org/web/20200406160604/https://books.google.com/books?id=uUlLCgAAQBAJ&pg=PA66|url-status=live}}</ref><ref name="Weeks20042">{{cite book|last=Weeks|first=Albert Loren|url=https://books.google.com/books?id=z3hP33KprskC&pg=PA135|title=Russia's Life-saver: Lend-lease Aid to the U.S.S.R. in World War II|publisher=Lexington Books|year=2004|isbn=978-0-7391-0736-2|page=135|access-date=7 January 2021|archive-date=6 April 2020|archive-url=https://web.archive.org/web/20200406160618/https://books.google.com/books?id=z3hP33KprskC&pg=PA135|url-status=live}}</ref>

From the early 20th century to 1980, the aluminium industry was characterized by cartelization, as aluminium firms colluded to keep prices high and stable.<ref>{{Cite book |last=Bertilorenzi |first=Marco |url=https://books.google.com/books?id=PASQCgAAQBAJ |title=The International Aluminium Cartel: The Business and Politics of a Cooperative Industrial Institution (1886-1978) |date=2015 |publisher=Routledge |isbn=978-1-317-80483-3 |language=en}}</ref> The first aluminium cartel, the Aluminium Association, was founded in 1901 by the Pittsburgh Reduction Company (renamed Alcoa in 1907) and Aluminium Industrie AG.<ref name="Fridenson-2024">{{cite journal |last1=Fridenson |first1=Patrick |title=Industrial Consumers Versus Cartelized Producers: The French Carmaker Louis Renault and the Aluminium Cartel, 1911–1944 |journal=Business History Review |date=2024 |volume=98 |issue=3 |pages=637–655 |doi=10.1017/S0007680524000692 }}</ref> The British Aluminium Company, Produits Chimiques d'Alais et de la Camargue, and Société Électro-Métallurgique de Froges also joined the cartel.<ref name="Fridenson-2024" />

By the mid-20th century, aluminium had become a part of everyday life and an essential component of housewares.{{sfn|Drozdov|2007|pp=69–70}} In 1954, production of aluminium surpassed that of copper,{{efn|Compare annual statistics of aluminium<ref name="USGS" /> and copper<ref name="USGS Copper">{{Cite report|chapter-url=https://minerals.usgs.gov/minerals/pubs/historical-statistics/|title=Historical Statistics for Mineral Commodities in the United States|chapter=Copper. Supply-Demand Statistics|year=2017|publisher=United States Geological Survey|language=en|access-date=4 June 2019|archive-url=https://web.archive.org/web/20180308171100/https://minerals.usgs.gov/minerals/pubs/historical-statistics/|archive-date=8 March 2018|url-status=live}}</ref> production by USGS.}} historically second in production only to iron,<ref>{{Cite web|last=Gregersen|first=Erik|title=Copper|url=https://www.britannica.com/science/copper|website=Encyclopedia Britannica|language=en|access-date=4 June 2019|archive-date=22 June 2019|archive-url=https://web.archive.org/web/20190622234613/https://www.britannica.com/science/copper|url-status=live}}</ref> making it the most produced non-ferrous metal. During the mid-20th century, aluminium emerged as a civil engineering material, with building applications in both basic construction and interior finish work,{{sfn|Drozdov|2007|pp=165–166}} and increasingly being used in military engineering, for both airplanes and armored vehicle engines.{{sfn|Drozdov|2007|p=85}} Earth's first artificial satellite, launched in 1957, consisted of two separate aluminium semi-spheres joined and all subsequent space vehicles have used aluminium to some extent.<ref name="aluminiumleader" /> The aluminium can was invented in 1956 and employed as a storage for drinks in 1958.{{sfn|Drozdov|2007|p=135}}

thumb|upright=1.0|lang=en|World production of aluminium since 1900

Throughout the 20th century, the production of aluminium rose rapidly: while the world production of aluminium in 1900 was 6,800 metric tons, the annual production first exceeded 100,000 metric tons in 1916; 1,000,000 tons in 1941; 10,000,000 tons in 1971.<ref name="USGS">{{Cite report|chapter-url=https://minerals.usgs.gov/minerals/pubs/historical-statistics/|title=Historical Statistics for Mineral Commodities in the United States|chapter=Aluminum|year=2017|publisher=United States Geological Survey|language=en|access-date=9 November 2017|archive-date=8 March 2018|archive-url=https://web.archive.org/web/20180308171100/https://minerals.usgs.gov/minerals/pubs/historical-statistics/|url-status=live}}</ref> In the 1970s, the increased demand for aluminium made it an exchange commodity; it entered the London Metal Exchange, the oldest industrial metal exchange in the world, in 1978.<ref name="aluminiumleader" /> The output continued to grow: the annual production of aluminium exceeded 50,000,000 metric tons in 2013.<ref name="USGS" />

The real price for aluminium declined from $14,000 per metric ton in 1900 to $2,340 in 1948 (in 1998 United States dollars).<ref name="USGS" /> Extraction and processing costs were lowered over technological progress and the scale of the economies. However, the need to exploit lower-grade poorer quality deposits and the use of fast increasing input costs (above all, energy) increased the net cost of aluminium;{{sfn|Nappi|2013|p=9}} the real price began to grow in the 1970s with the rise of energy cost.{{sfn|Nappi|2013|pp=9–10}}

Production moved from the industrialized countries to countries where production was cheaper.{{sfn|Nappi|2013|p=10}} Production costs in the late 20th century changed because of advances in technology, lower energy prices, exchange rates of the United States dollar, and alumina prices.{{sfn|Nappi|2013|pp=14–15}} The BRIC countries' combined share in primary production and primary consumption grew substantially in the first decade of the 21st century.{{sfn|Nappi|2013|p=17}} China is accumulating an especially large share of the world's production thanks to an abundance of resources, cheap energy, and governmental stimuli;{{sfn|Nappi|2013|p=20}} it also increased its consumption share from 2% in 1972 to 40% in 2010.{{sfn|Nappi|2013|p=22}} In the United States, Western Europe, and Japan, most aluminium was consumed in transportation, engineering, construction, and packaging.{{sfn|Nappi|2013|p=23}} In 2021, prices for industrial metals such as aluminium have soared to near-record levels as energy shortages in China drive up costs for electricity.<ref>{{cite news |title=Aluminum prices hit 13-year high amid power shortage in China |url=https://asia.nikkei.com/Business/Markets/Commodities/Aluminum-prices-hit-13-year-high-amid-power-shortage-in-China |work=Nikkei Asia |date=22 September 2021}}</ref>

== Etymology ==

The names ''aluminium'' and ''aluminum'' are derived from the word ''alumine'', an obsolete term for ''alumina'',{{efn|The spelling ''alumine'' comes from French, whereas the spelling ''alumina'' comes from Latin.<ref>{{cite book|last=Black|first=J.|url=http://archive.org/details/2543060RX2.nlm.nih.gov|title=Lectures on the elements of chemistry: delivered in the University of Edinburgh|date=1806|publisher=Graves, B.|page=291|volume=2}} {{blockquote|The French chemists have given a new name to this pure earth; alumine in French, and alumina in Latin. I confess I do not like this alumina.}}</ref>}} the primary naturally occurring oxide of aluminium.<ref name="OEDaluminium-origin">{{cite web |website=Oxford English Dictionary, third edition |title=aluminium, n. |url=https://www.oed.com/view/Entry/5889 |publisher=Oxford University Press |date=December 2011 |access-date=30 December 2020|archive-date=11 June 2021 |archive-url=https://web.archive.org/web/20210611060750/https://www.oed.com/start;jsessionid=103D1FF8ECD2A058B7F6241C7F97B88D?authRejection=true&url=%2Fview%2FEntry%2F5889 |url-status=live }} {{blockquote|'''Origin:''' Formed within English, by derivation. '''Etymons:''' {{smallcaps|alumine}}''n.'', {{smallcaps|-ium}} ''suffix'', {{smallcaps|aluminum}} ''n.''}}</ref> ''Alumine'' was borrowed from French, which in turn derived it from ''alumen'', the classical Latin name for alum, the mineral from which it was collected.<ref name="OEDalumine">{{cite web |website=Oxford English Dictionary, third edition |title=alumine, n. |url=https://www.oed.com/view/Entry/5880 |publisher=Oxford University Press |date=December 2011 |access-date=30 December 2020 |archive-date=11 June 2021 |archive-url=https://web.archive.org/web/20210611060739/https://www.oed.com/start;jsessionid=2B8662831CD405D28E3F852F18211FD4?authRejection=true&url=%2Fview%2FEntry%2F5880 |url-status=live }} {{blockquote|'''Etymology:''' < French ''alumine'' (L. B. Guyton de Morveau 1782, ''Observ. sur la Physique'' '''19''' 378) < classical Latin ''alūmin-'', ''alūmen'' {{smallcaps|alum}} ''n.''1, after French ''-ine'' {{smallcaps|-ine}} suffix4.}}</ref> The Latin word ''alumen'' stems from the Proto-Indo-European root ''*alu-'' meaning "bitter" or "beer".<ref>{{cite book |last=Pokorny |first=Julius |author-link=Julius Pokorny |title=Indogermanisches etymologisches Wörterbuch |trans-title=Indo-European etymological dictionary |language=de |url=https://indo-european.info/pokorny-etymological-dictionary/whnjs.htm |date=1959 |publisher=A. Francke Verlag |pages=33–34 |entry=alu- (-d-, -t-) |access-date=13 November 2017 |archive-date=23 November 2017 |archive-url=https://web.archive.org/web/20171123145109/https://indo-european.info/pokorny-etymological-dictionary/whnjs.htm |url-status=live }}</ref> The English name ''alum'' does not come directly from Latin, whereas ''alumine''/''alumina'' comes from the Latin word ''alumen'' (on declension, ''alumen'' changes to ''alumin-'').

== Naming and spelling history ==

=== Early proposals (1808–1812) ===

British chemist Humphry Davy, who performed a number of experiments aimed to isolate the metal, is credited as the person who named the element. The first name proposed for the metal to be isolated from alum was ''alumium'', which Davy suggested in an 1808 article on his electrochemical research, published in Philosophical Transactions of the Royal Society.<ref name="Davy1808">{{Cite journal|last1=Davy|first1=Humphry|date=1808|title=Electro Chemical Researches, on the Decomposition of the Earths; with Observations on the Metals obtained from the alkaline Earths, and on the Amalgam procured from Ammonia|url=https://books.google.com/books?id=Kg9GAAAAMAAJ&pg=RA1-PA353|journal=Philosophical Transactions of the Royal Society|volume=98|page=353|doi=10.1098/rstl.1808.0023|access-date=10 December 2009|doi-access=free|bibcode=1808RSPT...98..333D|archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415111945/https://books.google.com/books?id=Kg9GAAAAMAAJ&pg=RA1-PA353|url-status=live}}</ref> It appeared that the name was created from the English word ''alum'' and the Latin suffix ''-ium''; but it was customary then to give elements names originating in Latin, so this name was not adopted universally.

The name ''alumium'' was criticized by contemporary chemists from France, Germany, and Sweden, who insisted the metal should be named for the oxide, alumina, from which it would be isolated.{{sfn|Richards|1896|pp=3–4}} One example was ''Essai sur la Nomenclature chimique'' (July 1811), written in French by a Swedish chemist, Jöns Jacob Berzelius, in which the name ''aluminium'' is given to the element that would be synthesized from alum.<ref name="berzelius">{{cite journal|last=Berzelius|first=J. J.|title=Essai sur la nomenclature chimique|journal=Journal de Physique|volume=73|pages=253–286|year=1811|author-link=Jöns Jakob Berzelius|url=https://books.google.com/books?id=HpfOAAAAMAAJ&pg=PA253|access-date=27 December 2020|archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415120753/https://books.google.com/books?id=HpfOAAAAMAAJ&pg=PA253|url-status=live|trans-title=Essay on chemical nomenclature}}.</ref>{{efn|Davy discovered several other elements, including those he named ''sodium'' and ''potassium'', after the English words ''soda'' and ''potash''. Berzelius referred to them as to ''natrium'' and ''kalium''. Berzelius's suggestion was expanded in 1814<ref>{{cite journal|last=Berzelius|first=J.|author-link=Jöns Jacob Berzelius|title=Essay on the Cause of Chemical Proportions, and on some Circumstances relating to them: together with a short and easy Method of expressing them|editor-last=Thomson|editor-first=Th.|editor-link=Thomas Thomson (chemist)|year=1814|publisher=Baldwin, R.|journal=Annals of Philosophy|volume=III|pages=51–62|url=https://www.biodiversitylibrary.org/item/54032#page/5/mode/1up|access-date=13 December 2014|archive-date=15 July 2014|archive-url=https://web.archive.org/web/20140715120636/http://biodiversitylibrary.org/item/54032#page/5/mode/1up|url-status=live}}</ref> with his proposed system of one or two-letter chemical symbols, which are used up to the present day; sodium and potassium have the symbols ''Na'' and ''K'', respectively, after their Latin names.}} (Another article in the same journal issue also refers to the metal whose oxide is the basis of sapphire, i.e., the same metal, as to ''aluminium''.)<ref>{{cite journal|last=Delaméntherie|first=J.-C.|title=Leçonse de minéralogie. Données au collége de France|journal=Journal de Physique|volume=73|pages=469–470|year=1811|url=https://books.google.com/books?id=HpfOAAAAMAAJ&pg=PA470|access-date=27 December 2020|archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415114959/https://books.google.com/books?id=HpfOAAAAMAAJ&pg=PA470|url-status=live|trans-title=Mineralogy lessons. Given at the Collège de France}}.</ref> A January 1811 summary of one of Davy's lectures at the Royal Society mentioned the name ''aluminium'' as a possibility.<ref>{{Cite journal|date=January 1811|title=Philosophical Transactions of the Royal Society of London. For the Year 1810. — Part I|journal=The Critical Review: Or, Annals of Literature|series=The Third|volume=XXII|page=9|hdl=2027/chi.36013662?urlappend=%3Bseq=17|language=en}}{{blockquote|Potassium, acting upon alumine and glucine, produces pyrophoric substances of a dark grey colour, which burnt, throwing off brilliant sparks, and leaving behind alkali and earth, and which, when thrown into water, decomposed it with great violence. The result of this experiment is not wholly decisive as to the existence of what might be called ''aluminium'' and ''glucinium''}}</ref>

In 1812, Davy published his chemistry text ''Elements of Chemical Philosophy'' in which he used the spelling ''aluminum''.<ref name="Davy1812">{{cite book|chapter-url=https://books.google.com/books?id=YjMwAAAAYAAJ&pg=PA201|title=Elements of Chemical Philosophy: Part 1|last=Davy|first=Humphry|publisher=Bradford and Inskeep|year=1812|volume=1|page=201|chapter=Of metals; their primary compositions with other uncompounded bodies, and with each other|author-link=Humphry Davy|access-date=4 March 2020|archive-date=14 March 2020|archive-url=https://web.archive.org/web/20200314113620/https://books.google.com/books?id=YjMwAAAAYAAJ&pg=PA201|url-status=live}}</ref>

=== 19th-century spelling and usage ===

thumb|upright|1897 American advertisement featuring the ''aluminum'' spelling

In 1812, British scientist Thomas Young<ref>{{cite web|url=http://www.rc.umd.edu/reference/qr/index/15.html#contents|title=Quarterly Review Archive|last1=Cutmore|first1=Jonathan|website=Romantic Circles|publisher=University of Maryland|archive-url=https://web.archive.org/web/20170301094017/http://www.rc.umd.edu/reference/qr/index/15.html|archive-date=1 March 2017|url-status=live|date=February 2005|access-date=28 February 2017}}</ref> wrote an anonymous review of Davy's book, in which he proposed the name ''aluminium'' instead of ''aluminum'', which he thought had a "less classical sound".<ref>{{Cite journal |date=September 1812 |title=Elements of Chemical Philosophy By Sir Humphry Davy |type=Review |url=https://books.google.com/books?id=uGykjvn032IC&pg=PA72 |journal=Quarterly Review |volume=VIII |issue=15 |article-number=IV |page=72 |access-date=10 December 2009}}</ref> This name persisted: although the ''{{nowrap|-um}}'' spelling was occasionally used in Britain, the American scientific language used ''{{nowrap|-ium}}'' from the start.<ref name="Quinion2005" />

The French have used the spelling ''aluminium'' from the start.<ref name=Richards1891/> However, in England and Germany Davy's spelling ''aluminum'' was initially used; until Wöhler published his account of the Wöhler process in 1827 in which he used the spelling ''Aluminium'',{{efn|Wöhler had previously used ''Aluminium'' in 1824, when translating a paper by Jöns Jacob Berzelius from Swedish.<ref name=Richards1891/>}} which caused that spelling's largely wholesale adoption in England and Germany, with the exception of a small number of what Richards characterized as "patriotic" English chemists that were "averse to foreign innovations" who occasionally still used ''aluminum''.<ref name=Richards1891>{{cite journal|journal=Journal of the Franklin Institute|volume=131|issue=3|series=American periodical series, 1800–1850|publisher=Pergamon Press|date=March 1891|author1-first=Joseph W.|author1-last=Richards|title=The Aluminium Problem|pages=190–191|doi=10.1016/0016-0032(91)90249-3 |bibcode=1891FrInJ.131..189R }}</ref>

Most scientists throughout the world used ''{{nowrap|-ium}}'' in the 19th century;<ref name="OEDaluminium-usage" /> and it was entrenched in several other European languages, such as French, German, and Dutch.{{Efn|Some European languages, like Spanish or Italian, use a different suffix from the Latin ''-um''/''-ium'' to form a name of a metal, some, like Polish or Czech, have a different base for the name of the element, and some, like Russian or Greek, do not use the Latin script altogether.|name=|group=}}

In 1828, an American lexicographer, Noah Webster, entered only the ''aluminum'' spelling in his ''American Dictionary of the English Language''.<ref>{{Cite book|url=http://webstersdictionary1828.com/Dictionary/aluminum|title=American Dictionary of the English Language|last=Webster|first=Noah|year=1828|entry=aluminum|author-link=Noah Webster|access-date=13 November 2017|archive-date=13 November 2017|archive-url=https://web.archive.org/web/20171113222259/http://webstersdictionary1828.com/Dictionary/aluminum|url-status=live}}</ref> In the 1830s, the ''{{nowrap|-um}}'' spelling gained usage in the United States; by the 1860s, it had become the more common spelling there outside science.<ref name="Quinion2005">{{cite book|url=https://books.google.com/books?id=Js-PbsEjKSQC&pg=PT23|title=Port Out, Starboard Home: The Fascinating Stories We Tell About the words We Use|last=Quinion|first=Michael|publisher=Penguin Books Limited|year=2005|isbn=978-0-14-190904-2|pages=23–24}}</ref> In 1892, Hall used the ''{{nowrap|-um}}'' spelling in his advertising handbill for his new electrolytic method of producing the metal, despite his constant use of the ''{{nowrap|-ium}}'' spelling in all the patents he filed between 1886 and 1903. It is unknown whether this spelling was introduced by mistake or intentionally, but Hall preferred ''aluminum'' since its introduction because it resembled ''platinum'', the name of a prestigious metal.<ref>{{Cite book|last=Kean|first=S.|chapter-url=https://books.google.com/books?id=qy40DwAAQBAJ&q=aluminium+aluminum+hall+typo+spelling&pg=PT120|title=The Disappearing Spoon: And Other True Tales of Rivalry, Adventure, and the History of the World from the Periodic Table of the Elements|date=2018|publisher=Little, Brown Books for Young Readers|isbn=978-0-316-38825-2|pages=|language=en|chapter=Elements as money|edition=Young Readers|access-date=14 January 2021|archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415111942/https://books.google.com/books?id=qy40DwAAQBAJ&q=aluminium+aluminum+hall+typo+spelling&pg=PT120|url-status=live}}</ref> By 1890, both spellings had been common in the United States, the ''{{nowrap|-ium}}'' spelling being slightly more common; by 1895, the situation had reversed; by 1900, ''aluminum'' had become twice as common as ''aluminium''; in the next decade, the ''{{nowrap|-um}}'' spelling dominated American usage.

=== 20th-century standardization and regional usage ===

In 1925, the American Chemical Society adopted the spelling ''aluminum''.<ref name="OEDaluminium-usage" /> The International Union of Pure and Applied Chemistry (IUPAC) adopted ''aluminium'' as the standard international name for the element in 1990.<ref name="Emsley2011" /> In 1993, they recognized ''aluminum'' as an acceptable variant;<ref name="Emsley2011">{{cite book|last=Emsley|first=John|author-link=John Emsley|title=Nature's Building Blocks: An A–Z Guide to the Elements|url=https://books.google.com/books?id=2EfYXzwPo3UC&pg=PA24|year=2011|publisher=OUP Oxford|isbn=978-0-19-960563-7|pages=24–30|access-date=16 November 2017|archive-date=22 December 2019|archive-url=https://web.archive.org/web/20191222070959/https://books.google.com/books?id=2EfYXzwPo3UC&pg=PA24|url-status=live}}</ref> the most recent 2005 edition of the IUPAC nomenclature of inorganic chemistry also acknowledges this spelling.<ref>{{Cite book|url=https://www.iupac.org/fileadmin/user_upload/databases/Red_Book_2005.pdf|archive-url=https://web.archive.org/web/20141222172055/http://www.iupac.org/fileadmin/user_upload/databases/Red_Book_2005.pdf|archive-date=22 December 2014|editor1-first=Neil G.|editor1-last=Connelly|editor2-first=Ture|editor2-last=Damhus|title=Nomenclature of inorganic chemistry. IUPAC Recommendations 2005|publisher=RSC Publishing|year=2005|isbn=978-0-85404-438-2|page=249}}</ref> IUPAC official publications use the ''{{nowrap|-ium}}'' spelling as primary, and they list both where it is appropriate.{{efn|For instance, see the November–December 2013 issue of ''Chemistry International'': in a table of (some) elements, the element is listed as "aluminium (aluminum)".<ref>{{cite journal|title=Standard Atomic Weights Revised|author=|pages=17–18|url=https://www.iupac.org/publications/ci/2013/3506/nov13.pdf|archive-url=https://web.archive.org/web/20140211093133/http://www.iupac.org/publications/ci/2013/3506/nov13.pdf|archive-date=11 February 2014|journal=Chemistry International|volume=35|issue=6|issn=0193-6484}}</ref>}} Both spellings have coexisted since. Their usage is currently regional: ''aluminum'' dominates in the United States and Canada; ''aluminium'' is prevalent in the rest of the English-speaking world.<ref name="OEDaluminium-usage">{{cite web|website=Oxford English Dictionary, third edition|title=aluminium, n.|url=https://www.oed.com/view/Entry/5889|publisher=Oxford University Press|date=December 2011|access-date=30 December 2020|archive-date=11 June 2021|archive-url=https://web.archive.org/web/20210611060736/https://www.oed.com/start;jsessionid=7486FA56257A57791FB5DF1C726BAE1F?authRejection=true&url=%2Fview%2FEntry%2F5889|url-status=live}} {{blockquote|{{smallcaps|aluminium}} ''n.'' coexisted with its synonym {{smallcaps|aluminum}} ''n.'' throughout the 19th cent. From the beginning of the 20th cent., ''aluminum'' gradually became the predominant form in North America; it was adopted as the official name of the metal in the United States by the American Chemical Society in 1925. Elsewhere, ''aluminum'' was gradually superseded by ''aluminium'', which was accepted as international standard by IUPAC in 1990.}}</ref>

=== Other proposed names ===

German physicist Ludwig Wilhelm Gilbert had proposed ''Thonerde-metall'', after the German ''Thonerde''{{efn|a historic spelling, nowadays spelled "Tonerde"}} for alumina, in his ''Annalen der Physik'' but that name never caught on at all even in Germany.<ref name="Richards1891" /> American chemist Joseph W. Richards{{efn|founder and later president of the Electrochemical Society}} in 1891 found just one occurrence of ''argillium'' in Swedish, from the French ''argille''{{efn|nowadays spelled ''argile''}} for clay.<ref name="Richards1891" />

== Production and refinement ==

<div style="float: right; margin: 2px; font-size:85%; margin-left:18px; margin-bottom:18px> {| class="wikitable sortable collapsible" |+'''World's largest producing countries of aluminium, 2024'''<ref name="usgs"/> ! Country !! data-sort-type="number"|Output (thousand tons) |- | {{flagu|China}} || align="right"|43,000 |- | {{flagu|India}} || align="right"|4,200 |- | {{flagu|Russia}} || align="right"|3,800 |- | {{flagu|Canada}} || align="right"|3,300 |- | {{flagu|United Arab Emirates}} || align="right"|2,700 |- | {{flagu|Bahrain}} || align="right"|1,600 |- | {{flagu|Australia}} || align="right"|1,500 |- | {{flagu|Norway}} || align="right"|1,300 |- | {{flagu|Brazil}} || align="right"|1,100 |- | {{flagu|Malaysia}} || align="right"|870 |- | {{flagu|Iceland}} || align="right"|780 |- | {{flagu|United States}} || align="right"|670 |- | Other countries || align="right"|6,800 |- | Total || align="right"|72,000 |} </div>

The production of aluminium starts with the extraction of bauxite rock from the ground. The bauxite is processed and transformed using the Bayer process into alumina, which is then processed using the Hall–Héroult process, resulting in the final aluminium.

Aluminium production is highly energy-consuming, and so the producers tend to locate smelters in places where electric power is both plentiful and inexpensive.<ref name="WMP">{{cite book|url=http://www.bgs.ac.uk/downloads/start.cfm?id=1388|title=World Mineral Production 2003–2007|last1=Brown|first1=T.J.|date=2009|publisher=British Geological Survey|access-date=1 December 2014|archive-date=13 July 2019|archive-url=https://web.archive.org/web/20190713005219/http://www.bgs.ac.uk/downloads/start.cfm%3Fid%3D1388|url-status=live}}</ref> Production of one kilogram of aluminium requires 7 kilograms of oil energy equivalent, as compared to 1.5 kilograms for steel and 2 kilograms for plastic.<ref>{{Cite book |last=Lama |first=F. |title=Why the West Can't Win: From Bretton Woods to a Multipolar World |publisher=Clarity Press, Inc. |year=2023 |isbn=978-1-949762-74-7 |page=19}}</ref> As of 2024, the world's largest producers of aluminium were China, India, Russia, Canada, and the United Arab Emirates,<ref name="usgs">{{Cite journal |date=2025 |title=USGS Minerals Information: Mineral Commodity Summaries |url=https://pubs.usgs.gov/periodicals/mcs2025/mcs2025.pdf |language=en |doi=10.3133/mcs2025 |access-date=2 April 2025 |website=minerals.usgs.gov |author1=National Minerals Information Center }}</ref> while China is by far the top producer of aluminium with a world share of over 55%.

According to the International Resource Panel's Metal Stocks in Society report, the global per capita stock of aluminium in use in society (i.e. in cars, buildings, electronics, etc.) is {{convert|80|kg|abbr=on}}. Much of this is in more-developed countries ({{convert|350|–|500|kg|abbr=on}} per capita) rather than less-developed countries ({{convert|35|kg|abbr=on}} per capita).<ref>{{cite report |last1=Graedel|first1=T.E.|title=Metal stocks in Society – Scientific Synthesis|year=2010 |url=http://www.unep.fr/shared/publications/pdf/DTIx1264xPA-Metal%20stocks%20in%20society.pdf |isbn=978-92-807-3082-1|publisher=International Resource Panel|page=17|display-authors=etal|access-date=18 April 2017|archive-date=26 April 2018|archive-url=https://web.archive.org/web/20180426184751/http://www.unep.fr/shared/publications/pdf/DTIx1264xPA-Metal%20stocks%20in%20society.pdf|url-status=live}}</ref>

=== Bayer process ===

Bauxite is converted to alumina by the Bayer process. Bauxite is blended for uniform composition and then is ground fine. The resulting slurry is mixed with a hot solution of sodium hydroxide; the mixture is then treated in a digester vessel at a pressure well above atmospheric, dissolving the aluminium hydroxide in bauxite while converting impurities into relatively insoluble compounds:<ref name="UllmannOxide" />

{{block indent|Al(OH)3 + Na+ + OH− → Na+ + [Al(OH)4]−}}

After this reaction, the slurry is at a temperature above its atmospheric boiling point. It is cooled by removing steam as pressure is reduced. The bauxite residue is separated from the solution and discarded. The solution, free of solids, is seeded with small crystals of aluminium hydroxide; this causes decomposition of the [Al(OH)4]− ions to aluminium hydroxide. After about half of aluminium has precipitated, the mixture is sent to classifiers. Small crystals of aluminium hydroxide are collected to serve as seeding agents; coarse particles are converted to alumina by heating; the excess solution is removed by evaporation, (if needed) purified, and recycled.<ref name="UllmannOxide">{{Ullmann |last1=Hudson|first1=L. Keith|last2=Misra|first2=Chanakya|last3=Perrotta|first3=Anthony J.|last4=Wefers|first4=Karl|last5=Williams|first5=F.S.|date=2005 |publisher=Wiley-VCH|title=Aluminum Oxide|display-authors=3|doi=10.1002/14356007.a01_557}}</ref>

=== Hall–Héroult process ===

{{See also|List of countries by aluminium oxide production}} [[File:Tovarna glinice in aluminija Kidričevo - kupi aluminija 1968.jpg|thumb|upright=0.75|right|Extrusion billets of aluminium]]

The conversion of alumina to aluminium is achieved by the Hall–Héroult process. In this energy-intensive process, a solution of alumina in a molten ({{convert|940|and|970|C|F}}) mixture of cryolite (Na3AlF6) with calcium fluoride is electrolyzed to produce metallic aluminium. The liquid aluminium sinks to the bottom of the solution and is tapped off, and usually cast into large blocks called aluminium billets for further processing.<ref name="Ullmann" />

Anodes of the electrolysis cell are made of carbon—the most resistant material against fluoride corrosion—and either bake at the process or are prebaked. The former, also called Söderberg anodes, are less power-efficient and fumes released during baking are costly to collect, which is why they are being replaced by prebaked anodes even though they save the power, energy, and labor to prebake the cathodes. Carbon for anodes should be preferably pure so that neither aluminium nor the electrolyte is contaminated with ash. Despite carbon's resistivity against corrosion, it is still consumed at a rate of 0.4–0.5 kg per each kilogram of produced aluminium. Cathodes are made of anthracite; high purity for them is not required because impurities leach only very slowly. The cathode is consumed at a rate of 0.02–0.04 kg per each kilogram of produced aluminium. A cell is usually terminated after 2–6 years following a failure of the cathode.<ref name="Ullmann" />

The Hall–Heroult process produces aluminium with a purity of above 99%. Further purification can be done by the Hoopes process. This process involves the electrolysis of molten aluminium with a sodium, barium, and aluminium fluoride electrolyte. The resulting aluminium has a purity of 99.99%.<ref name="Ullmann" /><ref>{{cite book|url=https://books.google.com/books?id=KpgTrFloOq0C&pg=PA40|title=Handbook of Aluminum|last1=Totten|first1=G.E.|last2=Mackenzie|first2=D.S.|date=2003|publisher=Marcel Dekker|isbn=978-0-8247-4843-2|page=40|archive-url=https://web.archive.org/web/20160615132126/https://books.google.com/books?id=KpgTrFloOq0C&pg=PA40|archive-date=15 June 2016|url-status=live}}</ref>

Electric power represents about 20 to 40% of the cost of producing aluminium, depending on the location of the smelter. Aluminium production consumes roughly 5% of electricity generated in the United States.<ref name="Emsley2011" /> Because of this, alternatives to the Hall–Héroult process have been researched, but none has turned out to be economically feasible.<ref name="Ullmann" />

=== Recycling ===

thumb|Common bins for recyclable waste along with a bin for unrecyclable waste. The bin with a yellow top is labeled "aluminum". Rhodes, Greece.

Recovery of the metal through recycling has become an important task of the aluminium industry. Recycling was a low-profile activity until the late 1960s, when the growing use of aluminium beverage cans brought it to public awareness.<ref>{{cite book|url=https://books.google.com/books?id=DtX1nbel49kC|title=Aluminum Recycling|last=Schlesinger|first=Mark|publisher=CRC Press|year=2006|isbn=978-0-8493-9662-5|page=248|access-date=25 June 2018|archive-date=15 February 2017|archive-url=https://web.archive.org/web/20170215051211/https://books.google.com/books?id=DtX1nbel49kC|url-status=live}}</ref> Recycling involves melting the scrap, a process that requires only 5% of the energy used to produce aluminium from ore, though a significant part (up to 15% of the input material) is lost as dross (ash-like oxide).<ref>{{cite web|url=http://www.dnr.state.oh.us/recycling/awareness/facts/benefits.htm|title=Benefits of Recycling|publisher=Ohio Department of Natural Resources|archive-url=https://web.archive.org/web/20030624162738/http://www.dnr.state.oh.us/recycling/awareness/facts/benefits.htm|archive-date=24 June 2003}}</ref> An aluminium stack melter produces significantly less dross, with values reported below 1%.<ref>{{cite web|url=http://www.afsinc.org/files/best%20practice%20energy-schifo-radia-may%202004.pdf|title=Theoretical/Best Practice Energy Use in Metalcasting Operations|archive-url=https://web.archive.org/web/20131031072356/http://www.afsinc.org/files/best%20practice%20energy-schifo-radia-may%202004.pdf|archive-date=31 October 2013|access-date=28 October 2013}}</ref>

White dross from primary aluminium production and from secondary recycling operations still contains useful quantities of aluminium that can be extracted industrially. The process produces aluminium billets, together with a highly complex waste material. This waste is difficult to manage. It reacts with water, releasing a mixture of gases including, among others, acetylene,<ref>{{cite journal |last1=Manfredi |first1=O. |last2=Wuth |first2=W. |last3=Bohlinger |first3=I.|title=Characterizing the physical and chemical properties of aluminum dross |journal=JOM |date=November 1997|volume=49 |issue=11 |pages=48–51 |doi=10.1007/s11837-997-0012-9 |bibcode=1997JOM....49k..48M }}</ref> hydrogen sulfide and significant amounts of ammonia.<ref name = drossgas>{{cite journal |last1=Mahinroosta |first1=Mostafa |last2=Allahverdi |first2=Ali |title=Hazardous aluminum dross characterization and recycling strategies: A critical review |journal=Journal of Environmental Management |date=October 2018 |volume=223 |pages=452–468 |doi=10.1016/j.jenvman.2018.06.068 |pmid=29957419 |bibcode=2018JEnvM.223..452M }}</ref> Despite these difficulties, the waste is used as a filler in asphalt and concrete.<ref>{{cite web|url=http://aggregain.wrap.org.uk/document.rm?id=1753|archive-url=http://webarchive.nationalarchives.gov.uk/20100402111522/http://www.wrap.org.uk/downloads/BRE_Added_value_study_report.4ca28919.1753.pdf|archive-date=2 April 2010|title=Added value of using new industrial waste streams as secondary aggregates in both concrete and asphalt|last1=Dunster|first1=A.M.|date=2005|publisher=Waste & Resources Action Programme|display-authors=etal}}</ref> Its potential for hydrogen production has also been considered and researched.<ref>{{cite journal |last1=David |first1=E. |last2=Kopac |first2=J. |title=Hydrolysis of aluminum dross material to achieve zero hazardous waste |journal=Journal of Hazardous Materials |date=March 2012 |volume=209-210 |pages=501–509 |doi=10.1016/j.jhazmat.2012.01.064 |pmid=22326245 |bibcode=2012JHzM..209..501D }}</ref><ref>{{cite journal |last1=Meshram |first1=Arunabh |last2=Jain |first2=Anant |last3=Rao |first3=Mudila Dhanunjaya |last4=Singh |first4=Kamalesh Kumar |title=From industrial waste to valuable products: preparation of hydrogen gas and alumina from aluminium dross |journal=Journal of Material Cycles and Waste Management |date=July 2019 |volume=21 |issue=4 |pages=984–993 |doi=10.1007/s10163-019-00856-y |bibcode=2019JMCWM..21..984M }}</ref>

== Applications ==

[[File:Austin A40 Roadster ca 1951.jpg|thumb|upright=1.0|right|Aluminium-bodied Austin A40 Sports (c. 1951)]]

=== Metal ===

The global production of aluminium in 2016 was 58.8 million metric tons.{{Outdated statistic}} It exceeded that of any other metal except iron (1,231 million metric tons).<ref name="BGS2018">{{cite book|url=https://www.bgs.ac.uk/downloads/start.cfm?id=3396|title=World Mineral Production: 2012–2016|last1=Brown|first1=T.J.|last2=Idoine|first2=N.E.|last3=Raycraft|first3=E.R.|last4=Shaw|first4=R.A.|last5=Hobbs|first5=S.F.|last6=Everett|first6=P.|last7=Deady|first7=E.A.|last8=Bide|first8=T.|display-authors=3|date=2018|publisher=British Geological Survey|isbn=978-0-85272-882-6|access-date=10 July 2018|archive-date=16 May 2020|archive-url=https://web.archive.org/web/20200516174440/https://www.bgs.ac.uk/downloads/directDownload.cfm?id=3396&noexcl=true&t=World%20Mineral%20Production%202012%20to%202016|url-status=live}}</ref><ref>{{cite encyclopedia|title=Aluminum|encyclopedia=Encyclopædia Britannica|url=https://www.britannica.com/EBchecked/topic/17944/aluminum-Al|access-date=6 March 2012|archive-url=https://web.archive.org/web/20120312125740/https://www.britannica.com/EBchecked/topic/17944/aluminum-Al|archive-date=12 March 2012|url-status=live}}</ref>

Aluminium is almost always alloyed, which markedly improves its mechanical properties, especially when tempered. For example, the common aluminium foils and beverage cans are alloys of 92% to 99% aluminium.<ref>{{cite web|url=http://www.madehow.com/Volume-1/Aluminum-Foil.html|title=Aluminum Foil|last1=Millberg|first1=L.S.|website=How Products are Made|archive-url=https://web.archive.org/web/20070713102210/http://www.madehow.com/Volume-1/Aluminum-Foil.html|archive-date=13 July 2007|url-status=live|volume=1|access-date=11 August 2007}}</ref> The main alloying agents for both wrought and cast aluminium are copper, zinc, magnesium, manganese, and silicon (e.g., duralumin) with the levels of other metals in a few percent by weight.<ref>{{cite book|title=Ullmann's Encyclopedia of Industrial Chemistry|last1=Sanders|first1=R.E.|last2=Lyle|first2=J.P.|last3=Granger|first3=D.A.|date=2021|publisher=Wiley-VCH|chapter=Aluminum Alloys|doi=10.1002/14356007.a01_481.pub2|title-link=Ullmann's Encyclopedia of Industrial Chemistry|isbn=978-3-527-30673-2|page=6}}</ref><ref name="ross13">{{cite book|last1=Ross|first1=R.B.|title=Metallic Materials Specification Handbook|date=2013|publisher=Springer Science & Business Media|isbn=978-1-4615-3482-2|url=https://books.google.com/books?id=v171BwAAQBAJ|access-date=3 June 2021|archive-date=11 June 2021|archive-url=https://web.archive.org/web/20210611060734/https://books.google.com/books?id=v171BwAAQBAJ|url-status=live}}</ref>

[[File:Drinking can ring-pull tab.jpg|thumb|upright=1.0|Aluminium can]]

The major uses for aluminium are in:{{sfn|Davis|1999|pp=17–24}} * Transportation (automobiles, aircraft, trucks, railway cars, marine vessels, bicycles, spacecraft, ''etc.''). Aluminium is used because of its low density<ref>{{Cite web |title=Aluminum |url=https://www.mit.edu/~6.777/matprops/aluminum.htm |access-date=2025-10-14 |website=www.mit.edu}}</ref>, durability, and corrosion resistance; * Packaging (cans, foil, frame, etc.). Aluminium is used because it is non-toxic (see below), non-adsorptive, and splinter-proof; * Building and construction (windows, doors, siding, building wire, sheathing, roofing, ''etc.''). Since steel is cheaper, aluminium is used when lightness, corrosion resistance, or engineering features are important; * Electricity-related uses (conductor alloys, motors, and generators, transformers, capacitors, ''etc.''). Aluminium is used because it is relatively cheap, highly conductive, has adequate mechanical strength and low density, and resists corrosion; * A wide range of household items, from cooking utensils to furniture. Low density, good appearance, ease of fabrication, and durability are the key factors of aluminium usage. Aluminium is the material of choice for cookware, pans, dishes, and utensils because it heats up quickly, cools down quickly, and is cost-effective<ref>{{Cite web |date=2025-10-13 |title=6 Crucial Aluminum Uses in Daily Life (And Why It's Everywhere) |url=https://www.sputtertargets.net/blog/6-popular-aluminum-uses-in-our-daily-life.html |access-date=2025-10-14 |website=Stanford Advanced Materials |language=en-US}}</ref>. This is why it is used both in fast-food restaurants and in home kitchens; * Machinery and equipment (processing equipment, pipes, tools, t-slot framing). Aluminium is used because of its corrosion resistance, non-pyrophoricity, and mechanical strength.

Aluminium is the main substitute to copper and its applications to the traditional domains of copper have seen increased interest when copper prices are high such as in 2011–2014 and 2021.<ref name=cochilco>{{Cite report |title=Análisis de Minerales Críticos y/o Estratégicos |url=https://www.cochilco.cl/web/analisis-de-minerales-criticos-y-o-estrategicos/ |access-date=2026-03-25 |year=2024 |publisher=Chilean Copper Commission |language=es|trans-title=Analysis of Critical and/or Strategic Minerals|pages=58–60}}</ref> There is a competition in the use of aluminium and copper in the automotive industry, but in other uses such as in the construction industry and in underground and submarine cables aluminium has been largely unable to compete with copper.<ref name=cochilco/>

=== Compounds ===

The great majority (about 90%) of aluminium oxide is converted to metallic aluminium.<ref name="UllmannOxide" /> Being a very hard material (Mohs hardness 9),<ref name="Lumley2010">{{cite book|url=https://books.google.com/books?id=mXpwAgAAQBAJ&pg=PA42|title=Fundamentals of Aluminium Metallurgy: Production, Processing and Applications|last=Lumley|first=Roger|publisher=Elsevier Science|year=2010|isbn=978-0-85709-025-6|page=42|access-date=13 July 2018|archive-date=22 December 2019|archive-url=https://web.archive.org/web/20191222153110/https://books.google.com/books?id=mXpwAgAAQBAJ&pg=PA42|url-status=live}}</ref> alumina is widely used as an abrasive;<ref name="Mortensen2006">{{cite book|url=https://books.google.com/books?id=zs_lGeGsuaAC&pg=PA281|title=Concise Encyclopedia of Composite Materials|last=Mortensen|first=Andreas|publisher=Elsevier|year=2006|isbn=978-0-08-052462-7|page=281|access-date=13 July 2018|archive-date=20 December 2019|archive-url=https://web.archive.org/web/20191220232017/https://books.google.com/books?id=zs_lGeGsuaAC&pg=PA281|url-status=live}}</ref> being extraordinarily chemically inert, it is useful in highly reactive environments such as high pressure sodium lamps.<ref name="Japan2012">{{cite book|url=https://books.google.com/books?id=y8NNHruBKVQC&pg=PA541|title=Advanced Ceramic Technologies & Products|author=The Ceramic Society of Japan|year=2012|publisher=Springer Science & Business Media|isbn=978-4-431-54108-0|page=541|access-date=13 July 2018|archive-date=29 November 2019|archive-url=https://web.archive.org/web/20191129220847/https://books.google.com/books?id=y8NNHruBKVQC&pg=PA541|url-status=live}}</ref> Aluminium oxide is commonly used as a catalyst for industrial processes;<ref name="UllmannOxide" /> e.g. the Claus process to convert hydrogen sulfide to sulfur in refineries and to alkylate amines.<ref name="Slesser1988">{{cite book|url=https://books.google.com/books?id=kUOvCwAAQBAJ&pg=PA138|title=Dictionary of Energy|last=Slesser|first=Malcolm|publisher=Palgrave Macmillan UK|year=1988|isbn=978-1-349-19476-6|page=138|access-date=13 July 2018|archive-date=11 June 2021|archive-url=https://web.archive.org/web/20210611060750/https://books.google.com/books?id=kUOvCwAAQBAJ&pg=PA138|url-status=live}}</ref><ref name="Supp2013">{{cite book|url=https://books.google.com/books?id=vi3wCAAAQBAJ&pg=PA165|title=How to Produce Methanol from Coal|last=Supp|first=Emil|publisher=Springer Science & Business Media|year=2013|isbn=978-3-662-00895-9|pages=164–165|access-date=13 July 2018|archive-date=26 December 2019|archive-url=https://web.archive.org/web/20191226154639/https://books.google.com/books?id=vi3wCAAAQBAJ&pg=PA165|url-status=live}}</ref> Many industrial catalysts are supported by alumina, meaning that the expensive catalyst material is dispersed over a surface of the inert alumina.<ref name="ErtlKnözinger2008">{{cite book|url=https://books.google.com/books?id=ev47CMLmM2sC&pg=PA80|title=Preparation of Solid Catalysts|last1=Ertl|first1=Gerhard|last2=Knözinger|first2=Helmut|last3=Weitkamp|first3=Jens|year=2008|publisher=John Wiley & Sons|isbn=978-3-527-62068-5|page=80|access-date=13 July 2018|archive-date=24 December 2019|archive-url=https://web.archive.org/web/20191224115243/https://books.google.com/books?id=ev47CMLmM2sC&pg=PA80|url-status=live}}</ref> Another principal use is as a drying agent or absorbent.<ref name="UllmannOxide" /><ref name="ArmaregoChai2009">{{cite book|url=https://books.google.com/books?id=PTXyS7Yj6zUC&pg=PA155|title=Purification of Laboratory Chemicals|last1=Armarego|first1=W.L.F.|last2=Chai|first2=Christina|year=2009|publisher=Butterworth-Heinemann|isbn=978-0-08-087824-9|pages=73, 109, 116, 155|access-date=13 July 2018|archive-date=22 December 2019|archive-url=https://web.archive.org/web/20191222155719/https://books.google.com/books?id=PTXyS7Yj6zUC&pg=PA155|url-status=live}}</ref>

thumb|upright|Laser deposition of alumina on a substrate

Several sulfates of aluminium have industrial and commercial application. Aluminium sulfate (in its hydrate form) is produced on the annual scale of several millions of metric tons.<ref name="UllmannInorganic">{{cite book|title=Ullmann's Encyclopedia of Industrial Chemistry|last=Helmboldt|first=O.|date=2007|publisher=Wiley-VCH|chapter=Aluminum Compounds, Inorganic|doi=10.1002/14356007.a01_527.pub2|title-link=Ullmann's Encyclopedia of Industrial Chemistry|pages=1–17 |isbn=978-3-527-30673-2}}</ref> About two-thirds is consumed in water treatment.<ref name="UllmannInorganic" /> The next major application is in the manufacture of paper.<ref name="UllmannInorganic" /> It is also used as a mordant in dyeing, in pickling seeds, deodorizing of mineral oils, in leather tanning, and in production of other aluminium compounds.<ref name="UllmannInorganic" /> Two kinds of alum, ammonium alum and potassium alum, were formerly used as mordants and in leather tanning, but their use has significantly declined following availability of high-purity aluminium sulfate.<ref name="UllmannInorganic" /> Anhydrous aluminium chloride is used as a catalyst in chemical and petrochemical industries, the dyeing industry, and in synthesis of various inorganic and organic compounds.<ref name="UllmannInorganic" /> Aluminium hydroxychlorides are used in purifying water, in the paper industry, and as antiperspirants.<ref name="UllmannInorganic" /> Sodium aluminate is used in treating water and as an accelerator of solidification of cement.<ref name="UllmannInorganic" />

Many aluminium compounds have niche applications, for example: * Aluminium acetate in solution is used as an astringent.<ref name="WHO Formulary 2008">{{cite book |title=WHO Model Formulary 2008|year=2009 |veditors=Stuart MC, Kouimtzi M, Hill SR |isbn=978-92-4-154765-9|hdl=10665/44053 |publisher=World Health Organization|hdl-access=free}}</ref> * Aluminium phosphate is used in the manufacture of glass, ceramic, pulp and paper products, cosmetics, paints, varnishes, and in dental cement.<ref>{{Cite book|url=https://books.google.com/books?id=ueRsAAAAMAAJ&q=Aluminium+phosphate+used+in+the+manufacture+of+glass,+ceramic,+pulp+and+paper+products,+cosmetics,+paints,+varnishes,+and+in+dental+cement.|title=Occupational Skin Disease|date=1983|publisher=Grune & Stratton|isbn=978-0-8089-1494-5|language=en|access-date=14 June 2017|archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415120754/https://books.google.com/books?id=ueRsAAAAMAAJ&q=Aluminium+phosphate+used+in+the+manufacture+of+glass,+ceramic,+pulp+and+paper+products,+cosmetics,+paints,+varnishes,+and+in+dental+cement.|url-status=live}}</ref> * Aluminium hydroxide is used as an antacid, and mordant; it is used also in water purification, the manufacture of glass and ceramics, and in the waterproofing of fabrics.<ref>{{cite book|title=Fundamentals of pharmacology: a text for nurses and health professionals|author1=Galbraith, A|author2=Bullock, S|author3=Manias, E|author4=Hunt, B|author5=Richards, A|publisher=Pearson|year=1999|location=Harlow|page=482}}</ref><ref name="papich">{{Cite book|title=Saunders Handbook of Veterinary Drugs|last=Papich|first=Mark G.|date=2007|publisher=Saunders/Elsevier|isbn=978-1-4160-2888-8|edition=2nd|location=St. Louis, Mo|pages=15–16|chapter=Aluminum Hydroxide and Aluminum Carbonate}}</ref> * Lithium aluminium hydride is a powerful reducing agent used in organic chemistry.<ref>{{cite book |last1=Brown |first1=Weldon G. |title=Organic Reactions |chapter=Reductions by Lithium Aluminum Hydride |date=2011 |pages=469–510 |doi=10.1002/0471264180.or006.10 |isbn=978-0-471-26418-7 }}</ref><ref>{{cite encyclopedia|year=2007|title=Lithium Aluminium Hydride|encyclopedia=SASOL Encyclopaedia of Science and Technology|publisher=New Africa Books|url=https://books.google.com/books?id=1wS3aWR5SO4C&pg=PA143|page=143|isbn=978-1-86928-384-1|author1=Gerrans, G.C.|author2=Hartmann-Petersen, P.|access-date=6 September 2017|archive-date=23 August 2017|archive-url=https://web.archive.org/web/20170823221511/https://books.google.com/books?id=1wS3aWR5SO4C&pg=PA143|url-status=live}}</ref> * Organoaluminiums are used as Lewis acids and co-catalysts.<ref>{{cite journal|author1=M. Witt|author2=H.W. Roesky|year=2000|title=Organoaluminum chemistry at the forefront of research and development|url=http://tejas.serc.iisc.ernet.in/currsci/feb252000/NMC2.pdf|journal=Curr. Sci.|volume=78|issue=4|page=410|archive-url=https://web.archive.org/web/20141006124655/http://tejas.serc.iisc.ernet.in/currsci/feb252000/NMC2.pdf|archive-date=6 October 2014}}</ref> * Methylaluminoxane is a co-catalyst for Ziegler–Natta olefin polymerization to produce vinyl polymers such as polyethene.<ref>{{cite journal|author1=A. Andresen|author2=H.G. Cordes|author3=J. Herwig|author4=W. Kaminsky|author5=A. Merck|author6=R. Mottweiler|author7=J. Pein|author8=H. Sinn|author9=H.J. Vollmer|year=1976|title=Halogen-free Soluble Ziegler-Catalysts for the Polymerization of Ethylene|journal=Angew. Chem. Int. Ed.|volume=15|issue=10|pages=630–632|doi=10.1002/anie.197606301}}</ref> * Aqueous aluminium ions (such as aqueous aluminium sulfate) are used to treat against fish parasites such as ''Gyrodactylus salaris''.<ref name="AasKlemetsen2011">{{cite book|last1=Aas|first1=Øystein|last2=Klemetsen|first2=Anders|last3=Einum|first3=Sigurd|last4=Skurdal|first4=Jostein|display-authors=3|title=Atlantic Salmon Ecology|url=https://books.google.com/books?id=9lMZnUdUGZUC&pg=PA240|year=2011|publisher=John Wiley & Sons|isbn=978-1-4443-4819-4|page=240|access-date=14 July 2018|archive-date=21 December 2019|archive-url=https://web.archive.org/web/20191221202430/https://books.google.com/books?id=9lMZnUdUGZUC&pg=PA240|url-status=live}}</ref> * In many vaccines, certain aluminium salts serve as an immune adjuvant (immune response booster) to allow the protein in the vaccine to achieve sufficient potency as an immune stimulant.<ref name="Singh2007">{{cite book|last=Singh|first=Manmohan|title=Vaccine Adjuvants and Delivery Systems|url=https://books.google.com/books?id=7QKRrTPwuDYC&pg=PA112|year=2007|publisher=John Wiley & Sons|isbn=978-0-470-13492-4|pages=81–109|access-date=14 July 2018|archive-date=20 December 2019|archive-url=https://web.archive.org/web/20191220055221/https://books.google.com/books?id=7QKRrTPwuDYC&pg=PA112|url-status=live}}</ref> Until 2004, most of the adjuvants used in vaccines were aluminium-adjuvanted.<ref>{{cite journal |last1=Lindblad |first1=Erik B |title=Aluminium compounds for use in vaccines |journal=Immunology & Cell Biology |date=October 2004 |volume=82 |issue=5 |pages=497–505 |doi=10.1111/j.0818-9641.2004.01286.x |pmid=15479435 }}</ref>

== Biology ==

thumb|upright=1.3|Schematic of aluminium absorption by human skin.<ref name="health1">{{Cite journal | doi=10.1039/C3EM00374D| pmid=23982047| title=Human exposure to aluminium| journal=Environmental Science: Processes & Impacts| volume=15| issue=10| pages=1807–1816| year=2013| last1=Exley | first1=C.| bibcode=2013ESPI...15.1807E| doi-access=free}}</ref>

Despite its widespread occurrence in the Earth's crust, aluminium has no known function in biology.<ref name="Ullmann" /> At pH 6–9 (relevant for most natural waters), aluminium precipitates out of water as the hydroxide and is hence not available; most elements behaving this way have no biological role or are toxic.<ref name="wou">{{cite web|url=https://www.wou.edu/las/physci/ch412/natwater.htm|website=Western Oregon University|title=Environmental Applications. Part I. Common Forms of the Elements in Water|publisher=Western Oregon University|access-date=30 September 2019|archive-date=11 December 2018|archive-url=https://web.archive.org/web/20181211082553/http://www.wou.edu/las/physci/ch412/natwater.htm|url-status=live}}</ref> Aluminium sulfate has an LD50 of 6207 mg/kg (oral, mouse).<ref>{{cite web |url=https://www.fishersci.com/store/msds?partNumber=AC192430050&productDescription=ALUMINUM+SULFATE+99.999+5GR&vendorId=VN00032119&countryCode=US&language=en |access-date=5 March 2026|title=Safety data sheet for Aluminium Sulfate}}</ref> === Toxicity ===

Aluminium is classified as a non-carcinogen by the United States Department of Health and Human Services.<ref name="Piero3">{{cite journal|last=Dolara|first=Piero|date=21 July 2014|title=Occurrence, exposure, effects, recommended intake and possible dietary use of selected trace compounds (aluminium, bismuth, cobalt, gold, lithium, nickel, silver)|journal=International Journal of Food Sciences and Nutrition|volume=65|issue=8|pages=911–924|doi=10.3109/09637486.2014.937801|issn=1465-3478|pmid=25045935 }}</ref>{{efn|While aluminium per se is not carcinogenic, Söderberg aluminium production is, as is noted by the International Agency for Research on Cancer,<ref name="worldcat">{{Cite book|title=Polynuclear aromatic compounds. part 3, Industrial exposures in aluminium production, coal gasification, coke production, and iron and steel founding.|date=1984|publisher=International Agency for Research on Cancer |isbn=92-832-1534-6|oclc=11527472|pages=51–59}}</ref> likely due to exposure to polycyclic aromatic hydrocarbons.<ref>{{Cite journal|last1=Wesdock|first1=J. C.|last2=Arnold|first2=I. M. F.|date=2014|title=Occupational and Environmental Health in the Aluminum Industry|url= |journal=Journal of Occupational and Environmental Medicine|language=en-US|volume=56|issue=5 Suppl|pages=S5–S11|doi=10.1097/JOM.0000000000000071|pmid=24806726|pmc=4131940|issn=1076-2752}}</ref>}} A review published in 1988 said that there was little evidence that normal exposure to aluminium presents a risk to healthy adult,<ref name="gitelman88">{{cite book |url=https://books.google.com/books?id=wRnOytsi8boC&pg=PA90 |title=Physiology of Aluminum in Man |archive-url=https://web.archive.org/web/20160519101650/https://books.google.com/books?id=wRnOytsi8boC&pg=PA90|archive-date=19 May 2016 |series=Aluminum and Health |publisher=CRC Press |year=1988 |isbn=0-8247-8026-4 |page=90 }}</ref> and a 2014 multi-element toxicology review was unable to find deleterious effects of aluminium consumed in amounts not greater than 40 mg/day per kg of body mass.<ref name="Piero3" /> Most ingested aluminium is eliminated in feces, and much of what enters the bloodstream is excreted in urine; however, not all absorbed or parenterally administered aluminium is cleared through urinary excretion.<ref name="ganrot">{{cite journal |vauthors=Ganrot PO |title=Metabolism and possible health effects of aluminum |journal=Environmental Health Perspectives |volume=65 |pages=363–441 |date=March 1986 |pmid=2940082 |pmc=1474689 |doi=10.1289/ehp.8665363}}</ref><ref name="atsdr">{{Cite web|url=https://www.atsdr.cdc.gov/phs/phs.asp?id=1076&tid=34|title= Public Health Statement: Aluminum|website=ATSDR |language=en|access-date=18 July 2018|archive-date=12 December 2016|archive-url=https://web.archive.org/web/20161212212014/https://www.atsdr.cdc.gov/phs/phs.asp?id=1076&tid=34|url-status=live}}</ref>

=== Effects ===

Aluminium, although rarely, can cause vitamin D-resistant osteomalacia, erythropoietin-resistant microcytic anemia, and central nervous system alterations. People with kidney insufficiency are especially at a risk.<ref name="Piero3" /> Chronic ingestion of hydrated aluminium silicates (for excess gastric acidity control) may result in aluminium binding to intestinal contents and increased elimination of other metals, such as iron or zinc; sufficiently high doses (>50 g/day) can cause anemia.<ref name="Piero3" />

[[File:Al transport across human cells.jpg|thumb|upright=1.3|There are five major aluminium forms absorbed by human body: the free solvated trivalent cation (Al3+(aq)); low-molecular-weight, neutral, soluble complexes (LMW-Al0(aq)); high-molecular-weight, neutral, soluble complexes (HMW-Al0(aq)); low-molecular-weight, charged, soluble complexes (LMW-Al(L)n+/−(aq)); nano and micro-particulates (Al(L)n(s)). They are transported across cell membranes or cell epi-/endothelia through five major routes: (1) paracellular; (2) transcellular; (3) active transport; (4) channels; (5) adsorptive or receptor-mediated endocytosis.<ref name="health1" />]]

During the 1988 Camelford water pollution incident, people in Camelford had their drinking water contaminated with aluminium sulfate for several weeks. A final report into the incident in 2013 concluded it was unlikely that this had caused long-term health problems.<ref>{{cite web|title=Lowermoor Water Pollution incident "unlikely" to have caused long term health effects|publisher=Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment|date=18 April 2013|url=https://cot.food.gov.uk/sites/default/files/cot/cotpnlwpirv2.pdf|access-date=21 December 2019|url-status=live|archive-date=21 December 2019|archive-url=https://web.archive.org/web/20191221033817/https://cot.food.gov.uk/sites/default/files/cot/cotpnlwpirv2.pdf}}</ref>

Aluminium has been suspected of being a possible cause of Alzheimer's disease,<ref>{{Cite journal|last=Tomljenovic|first=Lucija|date=21 March 2011|title=Aluminum and Alzheimer's Disease: After a Century of Controversy, Is there a Plausible Link?|url=https://www.medra.org/servlet/aliasResolver?alias=iospress&doi=10.3233/JAD-2010-101494|journal=Journal of Alzheimer's Disease|volume=23|issue=4|pages=567–598|doi=10.3233/JAD-2010-101494|pmid=21157018|access-date=11 June 2021|archive-date=11 June 2021|archive-url=https://web.archive.org/web/20210611060821/https://content.iospress.com/articles/journal-of-alzheimers-disease/jad101494|url-status=live}}</ref> but research into this for over 40 years has found, {{as of|2018|lc=yes}}, no good evidence of causal effect.<ref>{{cite web |title=Aluminum and dementia: Is there a link?|date=24 August 2018 |website=Alzheimer Society Canada |url=https://alzheimer.ca/en/Home/About-dementia/Alzheimer-s-disease/Risk-factors/Aluminum|access-date=21 December 2019|url-status=live |archive-date=21 December 2019|archive-url=https://web.archive.org/web/20191221040250/https://alzheimer.ca/en/Home/About-dementia/Alzheimer-s-disease/Risk-factors/Aluminum}}</ref><ref>{{Cite journal|last1=Santibáñez|first1=Miguel|last2=Bolumar|first2=Francisco|last3=García|first3=Ana M|date=2007|title=Occupational risk factors in Alzheimer's disease: a review assessing the quality of published epidemiological studies|journal=Occupational and Environmental Medicine|volume=64|issue=11|pages=723–732|doi=10.1136/oem.2006.028209|issn=1351-0711|pmc=2078415|pmid=17525096}}</ref>

Aluminium increases estrogen-related gene expression in human breast cancer cells cultured in the laboratory.<ref>{{cite journal |last1=Darbre |first1=P. D. |title=Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast |journal=Journal of Applied Toxicology |date=May 2006 |volume=26 |issue=3 |pages=191–197 |doi=10.1002/jat.1135 |pmid=16489580 }}</ref> In very high doses, aluminium is associated with altered function of the blood–brain barrier.<ref>{{cite journal |last1=Banks |first1=William A. |last2=Kastin |first2=Abba J. |title=Aluminum-Induced neurotoxicity: Alterations in membrane function at the blood-brain barrier |journal=Neuroscience & Biobehavioral Reviews |date=March 1989 |volume=13 |issue=1 |pages=47–53 |doi=10.1016/s0149-7634(89)80051-x |pmid=2671833 |bibcode=1989NBRev..13...47B }}</ref> A small percentage of people<ref name="BinghamCohrssen2012">{{cite book |url=https://books.google.com/books?id=1mk3lFVtBSQC&pg=PA244|title=Patty's Toxicology, 6 Volume Set|last1=Bingham|first1=Eula|last2=Cohrssen|first2=Barbara|year=2012|publisher=John Wiley & Sons|isbn=978-0-470-41081-3|page=244|access-date=23 July 2018|archive-date=20 December 2019|archive-url=https://web.archive.org/web/20191220172223/https://books.google.com/books?id=1mk3lFVtBSQC&pg=PA244|url-status=live}}</ref> have contact allergies to aluminium and experience itchy red rashes, headache, muscle pain, joint pain, poor memory, insomnia, depression, asthma, irritable bowel syndrome, or other symptoms upon contact with products containing aluminium.<ref>{{Cite news |url=https://allergy-symptoms.org/aluminum-allergy/|title=Aluminum Allergy Symptoms and Diagnosis|date=20 September 2016|work=Allergy-symptoms.org|access-date=23 July 2018 |language=en-US|archive-date=23 July 2018|archive-url=https://web.archive.org/web/20180723152243/https://allergy-symptoms.org/aluminum-allergy/|url-status=live}}</ref>

Exposure to powdered aluminium or aluminium welding fumes can cause pulmonary fibrosis.<ref>{{Cite journal|last1=al-Masalkhi|first1=A.|last2=Walton|first2=S.P.|date=1994|title=Pulmonary fibrosis and occupational exposure to aluminum|journal=The Journal of the Kentucky Medical Association|volume=92|issue=2|pages=59–61|issn=0023-0294|pmid=8163901}}</ref> Fine aluminium powder can ignite or explode, posing another workplace hazard.<ref>{{cite web|url=https://www.cdc.gov/niosh/npg/npgd0022.html|title=CDC – NIOSH Pocket Guide to Chemical Hazards – Aluminum|website=www.cdc.gov|archive-url=https://web.archive.org/web/20150530203735/http://www.cdc.gov/niosh/npg/npgd0022.html|archive-date=30 May 2015|url-status=live|access-date=11 June 2015}}</ref><ref>{{cite web|url=https://www.cdc.gov/niosh/npg/npgd0023.html|title=CDC – NIOSH Pocket Guide to Chemical Hazards – Aluminum (pyro powders and welding fumes, as Al)|website=www.cdc.gov|archive-url=https://web.archive.org/web/20150530205127/http://www.cdc.gov/niosh/npg/npgd0023.html|archive-date=30 May 2015|url-status=live|access-date=11 June 2015}}</ref>

=== Exposure routes ===

Food is the main source of aluminium. Drinking water contains more aluminium than solid food;<ref name="Piero3" /> however, aluminium in food may be absorbed more than aluminium from water.<ref name="Yokel2008">{{cite journal|author=Yokel R.A.|author2=Hicks C.L.|author3=Florence R.L.|date=2008|title=Aluminum bioavailability from basic sodium aluminum phosphate, an approved food additive emulsifying agent, incorporated in cheese|journal=Food and Chemical Toxicology|volume=46|issue=6|pages=2261–2266|doi=10.1016/j.fct.2008.03.004|pmc=2449821|pmid=18436363}}</ref> Major sources of human oral exposure to aluminium include food (due to its use in food additives, food and beverage packaging, and cooking utensils), drinking water (due to its use in municipal water treatment), and aluminium-containing medications (particularly antacid/antiulcer and buffered aspirin formulations).<ref>{{Cite report|author=United States Department of Health and Human Services|url=http://abcmt.org/tp22.pdf|title=Toxicological profile for aluminum|date=1999|access-date=3 August 2018|archive-date=9 May 2020|archive-url=https://web.archive.org/web/20200509192819/http://abcmt.org/tp22.pdf|url-status=live}}</ref> Dietary exposure in Europeans averages to 0.2–1.5 mg/kg/week but can be as high as 2.3 mg/kg/week.<ref name="Piero3" /> Higher exposure levels of aluminium are mostly limited to plumbers, masons, electrical workers, machinists, and surgeons.<ref>{{Cite web |title=Aluminum——Exposure Sources & Industrial Hygiene_Chemicalbook |url=https://www.chemicalbook.com/article/aluminum-exposure-sources-industrial-hygiene.htm |access-date=2025-06-14 |website=www.chemicalbook.com}}</ref>

Consumption of antacids, antiperspirants, vaccines, and cosmetics provide possible routes of exposure.<ref name="ChenThyssen2018">{{cite book|url=https://books.google.com/books?id=hKlVDwAAQBAJ&pg=PA333|title=Metal Allergy: From Dermatitis to Implant and Device Failure|last1=Chen|first1=Jennifer K.|last2=Thyssen|first2=Jacob P.|publisher=Springer|year=2018|isbn=978-3-319-58503-1|page=333|access-date=23 July 2018|archive-date=26 December 2019|archive-url=https://web.archive.org/web/20191226141303/https://books.google.com/books?id=hKlVDwAAQBAJ&pg=PA333|url-status=live}}</ref> Consumption of acidic foods or liquids with aluminium enhances aluminium absorption,<ref>{{cite journal|author=Slanina, P.|last2=French|first2=W.|last3=Ekström|first3=L.G.|last4=Lööf|first4=L.|last5=Slorach|first5=S.|last6=Cedergren|first6=A.|date=1986|title=Dietary citric acid enhances absorption of aluminum in antacids|journal=Clinical Chemistry|volume=32|issue=3|pages=539–541|pmid=3948402|doi=10.1093/clinchem/32.3.539}}</ref> and maltol has been shown to increase the accumulation of aluminium in nerve and bone tissues.<ref>{{cite journal|last1=Van Ginkel|first1=M.F.|last2=Van Der Voet|first2=G.B.|last3=D'haese|first3=P.C.|last4=De Broe|first4=M.E.|last5=De Wolff|first5=F.A.|date=1993|title=Effect of citric acid and maltol on the accumulation of aluminum in rat brain and bone|journal=The Journal of Laboratory and Clinical Medicine|volume=121|issue=3|pages=453–460|pmid=8445293}}</ref>

=== Treatment ===

In case of suspected sudden intake of a large amount of aluminium, the only treatment is deferoxamine mesylate which may be given to help eliminate aluminium from the body by chelation therapy.<ref name="Toxicity">{{Cite web|url=http://www.arltma.com/Articles/AlumToxDoc.htm|title=ARL: Aluminum Toxicity|website=www.arltma.com|access-date=24 July 2018|archive-date=31 August 2019|archive-url=https://web.archive.org/web/20190831154809/http://www.arltma.com/Articles/AlumToxDoc.htm}}</ref><ref>[http://www.med.nyu.edu/content?ChunkIID=164929 Aluminum Toxicity] {{webarchive|url=https://web.archive.org/web/20140203055539/http://www.med.nyu.edu/content?ChunkIID=164929|date=3 February 2014}} from NYU Langone Medical Center. Last reviewed November 2012 by Igor Puzanov, MD</ref> However, this should be applied with caution as this reduces not only aluminium body levels, but also those of other metals such as copper or iron.<ref name="Toxicity" />

== Environmental effects ==

[[File:Luftaufnahmen Nordseekueste 2012-05-by-RaBoe-478.jpg|thumb|upright=1.0|"Bauxite tailings" storage facility in Stade, Germany. The aluminium industry generates about 70 million tons of this waste annually.]] High levels of aluminium occur near mining sites; small amounts of aluminium are released to the environment at coal-fired power plants or incinerators.<ref name="atsdr"/> 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.<ref name="atsdr" />

Acidic precipitation is the main natural factor to mobilize aluminium from natural sources<ref name="Piero3" /> and the main reason for the environmental effects of aluminium;<ref name="RosselandEldhuset1990">{{cite journal|last1=Rosseland|first1=B.O.|last2=Eldhuset|first2=T.D.|last3=Staurnes|first3=M.|year=1990|title=Environmental effects of aluminium|journal=Environmental Geochemistry and Health|volume=12|issue=1–2|pages=17–27|doi=10.1007/BF01734045|pmid=24202562|bibcode=1990EnvGH..12...17R }}</ref> however, the main factor of presence of aluminium in salt and freshwater are the industrial processes that also release aluminium into air.<ref name="Piero3" />

In water, aluminium acts as a toxic agent on gill-breathing animals such as fish when the water is acidic, in which aluminium may precipitate on gills,<ref>{{cite journal |last1=Baker |first1=Joan P. |last2=Schofield |first2=Carl L. |title=Aluminum toxicity to fish in acidic waters |journal=Water, Air, and Soil Pollution |date=July 1982 |volume=18 |issue=1–3 |pages=289–309 |doi=10.1007/BF02419419 |bibcode=1982WASP...18..289B }}</ref> which causes loss of plasma- and hemolymph ions leading to osmoregulatory failure.<ref name="RosselandEldhuset1990" /> Organic complexes of aluminium may be easily absorbed and interfere with metabolism in mammals and birds, even though this rarely happens in practice.<ref name="RosselandEldhuset1990" />

Aluminium is primary among the factors that reduce plant growth on acidic soils. Although it is generally harmless to plant growth in pH-neutral soils, in acid soils the concentration of toxic Al3+ cations increases and disturbs root growth and function.<ref>{{cite journal |title=Effect of aluminum on δ-aminolevulinic acid dehydratase (ALA-D) and the development of cucumber (''Cucumis sativus'') |first1=Luciane|last1=Belmonte Pereira |first2=Luciane|last2=Aimed Tabaldi |first3=Jamile|last3=Fabbrin Gonçalves |first4=Gladis Oliveira|last4=Jucoski |first5=Mareni Maria|last5=Pauletto |first6=Simone|last6=Nardin Weis |first7=Fernando|last7=Texeira Nicoloso |first8=Denise|last8= Brother |first9=João|last9=Batista Teixeira Rocha |first10=Maria Rosa Chitolina|last10=Chitolina Schetinger |journal=Environmental and Experimental Botany|volume=57|issue=1–2|pages=106–115|date=2006|doi = 10.1016/j.envexpbot.2005.05.004|bibcode=2006EnvEB..57..106P }}</ref><ref>{{cite journal |last1=Andersson |first1=Maud |title=Toxicity and tolerance of aluminium in vascular plants: A literature review |journal=Water, Air, and Soil Pollution |date=June 1988 |volume=39 |issue=3–4 |pages=439–462 |doi=10.1007/BF00279487 |bibcode=1988WASP...39..439A }}</ref><ref>{{Cite web |date=2021-05-28 |title=Quảng Cáo ATA |url=https://quangcaoata.com/ |access-date=2026-04-23}}</ref><ref>{{cite journal |title=The role of the apoplast in aluminium toxicity and resistance of higher plants: A review |first=Walter J.|last=Horst |journal=Zeitschrift für Pflanzenernährung und Bodenkunde|volume=158|issue=5|pages=419–428|date=1995|doi=10.1002/jpln.19951580503 |bibcode=1995ZPflD.158..419H }} </ref><ref>{{cite journal |title = Aluminium tolerance in plants and the complexing role of organic acids |first1 = Jian Feng |last1 = Ma |journal = Trends in Plant Science |volume = 6 |issue = 6 |pages = 273–278 |date = 2001 |doi = 10.1016/S1360-1385(01)01961-6 |pmid = 11378470 |last2 = Ryan |first2 = P.R. |last3 = Delhaize |first3 = E.|bibcode = 2001TPS.....6..273M }}</ref> Wheat has developed a tolerance to aluminium, releasing organic compounds that bind to harmful aluminium cations. Sorghum is believed to have the same tolerance mechanism.<ref>{{cite journal |title = Comparative Mapping of a Major Aluminum Tolerance Gene in Sorghum and Other Species in the Poaceae |first8 = L.V.|last8 = Kochian |first7 = L.|last7 = Li |first6 = R.E.|last6 = Schaffert |first5 = P.E.|last5 = Klein |first4 = M.E.|last4 = Sorrells|first3 = Y.|last3 = Wang|first2 = D.F.|last2 = Garvin|author = Magalhaes, J.V. |journal = Genetics|volume = 167| issue = 4|date = 2004|pmid = 15342528|pmc = 1471010|doi = 10.1534/genetics.103.023580|pages = 1905–1914 | bibcode=2004Genet.167.1905M }}</ref>

Aluminium production possesses its own challenges to the environment on each step of the production process. The major challenge is the emission of greenhouse gases. These gases result from electrical consumption of the smelters and the byproducts of processing.<ref>{{cite journal |last1=Saevarsdottir |first1=Gudrun |last2=Kvande |first2=Halvor |last3=Welch |first3=Barry J. |title=Aluminum Production in the Times of Climate Change: The Global Challenge to Reduce the Carbon Footprint and Prevent Carbon Leakage |journal=JOM |date=January 2020 |volume=72 |issue=1 |pages=296–308 |doi=10.1007/s11837-019-03918-6 }}</ref> The most potent of these gases are perfluorocarbons, namely CF4 and C2F6, from the smelting process.<ref>{{cite journal |last1=Abrahamson |first1=Dean |title=Aluminium and global warming |journal=Nature |date=9 April 1992 |volume=356 |issue=6369 |page=484 |doi=10.1038/356484a0 |bibcode=1992Natur.356..484A }}</ref>

Biodegradation of metallic aluminium is extremely rare; most aluminium-corroding organisms do not directly attack or consume the aluminium, but instead produce corrosive wastes.<ref>{{cite web|publisher=Duncan Aviation |title=Fuel System Contamination & Starvation |date=2011 |url=http://www.duncanaviation.aero/intelligence/201102/fuel_starvation_system_contamination.php |archive-url=https://web.archive.org/web/20150225051128/http://www.duncanaviation.aero/intelligence/201102/fuel_starvation_system_contamination.php |archive-date=25 February 2015 }}</ref><ref>{{cite journal|quote=A ''Geotrichum''-type arthroconidial fungus was isolated by the authors from a deteriorated compact disc found in Belize (Central America)....In the present paper, we report the purification and characterization of an H2O2-generating extracellular oxidase produced by this fungus, which shares catalytic properties with both ''P. eryngii'' AAO and ''P. simplicissimum'' VAO.|volume=Proteins and Proteomics 1794|issue=4|date=April 2009|pages=689–697|title=New oxidase from ''Bjerkandera'' arthroconidial anamorph that oxidizes both phenolic and nonphenolic benzyl alcohols|first1=Elvira|last1=Romero|first2=Patricia|last2=Ferreira|first3=Ángel T.|last3=Martínez|first4=María|last4=Jesús Martínez|journal=Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics |doi=10.1016/j.bbapap.2008.11.013|pmid=19110079 }} See also the abstract of {{harvnb|Romero|Speranza|García-Guinea|Martínez|2007}}.</ref> The fungus ''Geotrichum candidum'' can consume the aluminium in compact discs.<ref>{{cite journal |last1=Bosch |first1=Xavier |title=Fungus eats CD |journal=Nature |date=27 June 2001 |doi=10.1038/news010628-11 }}</ref><ref>{{cite journal|journal=Naturwissenschaften|year=2001|volume=88|pages=351–354|doi=10.1007/s001140100249|department=Short Communication|first1=Javier|last1=Garcia-Guinea|first2=Victor|last2=Cárdenes|first3=Angel T.|last3=Martínez|first4=Maria|last4=Jesús Martínez|title=Fungal bioturbation paths in a compact disk|issue=8 |pmid=11572018 |bibcode=2001NW.....88..351G }}</ref><ref>{{cite journal|title=An anamorph of the white-rot fungus ''Bjerkandera adusta'' capable of colonizing and degrading compact disc components|first1=Elvira|last1=Romero|first2=Mariela|last2=Speranza|first3=Javier|last3=García-Guinea|first4=Ángel T.|last4=Martínez|first5=María|last5=Jesús Martínez|date=8 August 2007|doi=10.1111/j.1574-6968.2007.00876.x|editor-first=Bernard|editor-last=Prior|journal=FEMS Microbiol Lett|volume=275|issue=1 |pages=122–129|publisher=Blackwell Publishing Ltd.|pmid=17854471 |doi-access=free|hdl=10261/47650|hdl-access=free}}</ref> The bacterium ''Pseudomonas aeruginosa'' and the fungus ''Cladosporium resinae'' are commonly detected in aircraft fuel tanks that use kerosene-based fuels (not avgas), and laboratory cultures can degrade aluminium.<ref>{{cite journal |url=http://nzetc.victoria.ac.nz/tm/scholarly/tei-Bio19Tuat01-t1-body-d4.html |journal=Tuatara |title=Studies on the "Kerosene Fungus" ''Cladosporium resinae'' (Lindau) De Vries: Part I. The Problem of Microbial Contamination of Aviation Fuels |page=29 |author1=Sheridan, J.E. |author2=Nelson, Jan |author3=Tan, Y.L. |volume=19 |issue=1 |url-status=live|archive-url=https://web.archive.org/web/20131213140543/http://nzetc.victoria.ac.nz/tm/scholarly/tei-Bio19Tuat01-t1-body-d4.html |archive-date=13 December 2013 }}</ref>

== See also == {{Portal|Chemistry}} * Aluminium granules * Aluminium joining * Aluminium–air battery * Aluminized steel, for corrosion resistance and other properties * Aluminized screen, for display devices * Aluminized cloth, to reflect heat * Aluminized mylar, to reflect heat * Panel edge staining * Quantum clock

== Notes == {{notelist}}

== References == {{Reflist}} {{sfn whitelist|CITEREFGreenwoodEarnshaw1997}}

== Bibliography == * {{cite book |last=Davis|first=J. R.|url=https://books.google.com/books?id=iEeiQEeLOmYC|title=Corrosion of Aluminum and Aluminum Alloys|date=1999|publisher=ASM International|isbn=978-1-61503-238-9|language=en}} * {{cite book |title=Lange's handbook of chemistry |last=Dean |first=J. A. |date=1999 |publisher=McGraw-Hill |isbn=978-0-07-016384-3 |edition=15 |oclc=40213725}} * {{cite book |last = Drozdov |first = A. |year = 2007 |title = Aluminium: The Thirteenth Element |title-link = Aluminium: The Thirteenth Element |publisher = RUSAL Library |isbn = 978-5-91523-002-5}} * {{cite book |last=King |first=R. B. |date=1995 |title=Inorganic Chemistry of Main Group Elements |publisher=Wiley-VCH |isbn=978-0-471-18602-1}} * {{cite book |editor-last=Lide|editor-first=D. R.|title=Handbook of Chemistry and Physics|url=https://archive.org/details/crchandbookofche81lide|url-access=registration|publisher=CRC Press|date=2004|edition=84|isbn=978-0-8493-0566-5}} * {{cite report |last=Nappi |first=C. |year=2013 |title=The global aluminium industry 40 years from 1972 |publisher=International Aluminium Institute |url=http://large.stanford.edu/courses/2016/ph240/mclaughlin1/docs/nappi.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://large.stanford.edu/courses/2016/ph240/mclaughlin1/docs/nappi.pdf |archive-date=9 October 2022 |url-status=live}} * {{cite book |last=Richards |first=J. W. |year=1896 |url=https://archive.org/stream/cu31924003633751/cu31924003633751_djvu.txt |title=Aluminium: Its history, occurrence, properties, metallurgy and applications, including its alloys |edition=3 |publisher=Henry Carey Baird & Co.}} * {{cite book|last=Schmitz|first=C.|url=https://books.google.com/books?id=WvT2OEf8DskC|title=Handbook of Aluminium Recycling|date=2006|publisher=Vulkan-Verlag GmbH|isbn=978-3-8027-2936-2|language=en}}

== Further reading == * {{cite book |last1=Sheller |first1=Mimi |title=Aluminum Dreams |date=2014 |doi=10.7551/mitpress/9626.001.0001 |isbn=978-0-262-32136-5 }}

== External links == {{Sister project links|auto=1|wikt=aluminium|s=1911 Encyclopædia Britannica/Aluminium}} * [https://www.periodicvideos.com/videos/013.htm Aluminium] at ''The Periodic Table of Videos'' (University of Nottingham) * [https://www.atsdr.cdc.gov/ToxProfiles/tp22.pdf Toxicological Profile for Aluminum] (PDF) (September 2008) – 357-page report from the United States Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry * [https://www.cdc.gov/niosh/npg/npgd0022.html Aluminum] entry (last reviewed 30 October 2019) in the ''NIOSH Pocket Guide to Chemical Hazards'' published by the CDC's National Institute for Occupational Safety and Health * [https://www.indexmundi.com/commodities/?commodity=aluminum&months=300 Current and historical prices] (1998–present) for aluminum futures on the global commodities market * {{Internet Archive short film|id=gov.archives.arc.38661|name=Aluminum}} * usgs.gov (Mineral Commodity Summaries 2025): [https://pubs.usgs.gov/periodicals/mcs2025/mcs2025.pdf#page=32 Aluminum]

Category:Aluminium Category:Chemical elements Category:Post-transition metals Aluminium Category:Electrical conductors Category:Pyrotechnic fuels Category:Reducing agents Category:E-number additives Category:Native element minerals Category:Chemical elements with face-centered cubic structure Category:Building materials