编辑“︁镓”︁（章节）

==存在==
镓在地球地壳中不以单质存在，而像是gallite（CuGaS<sub>2</sub>）的高镓矿物则因为太稀有而不能作为镓的主要来源。<ref name=":1">{{cite journal|url=https://www.researchgate.net/publication/309583931|title=The distribution of gallium, germanium and indium in conventional and non-conventional resources – Implications for global availability (PDF Download Available)|website=ResearchGate|doi=10.13140/rg.2.2.20956.18564|access-date=2017-06-02|year=2016|last1=Frenzel|first1=Max|journal=|archive-date=2018-10-06|archive-url=https://web.archive.org/web/20181006235214/https://www.researchgate.net/publication/309583931}}</ref>镓[[地球的地壳元素丰度列表|在地球地壳中的丰度]]约为16.9&nbsp;[[百万分率|ppm]]，<ref name="Burton">{{cite journal |doi= 10.1016/0016-7037(59)90052-3 |title= The abundances of gallium and germanium in terrestrial materials|first= J. D.|last= Burton |author2= Culkin, F. |author3=Riley, J. P. |journal= Geochimica et Cosmochimica Acta|volume= 16|issue= 1|date= 2007 |pages= 151–180|bibcode= 1959GeCoA..16..151B}}</ref>可以和[[铅]]、[[钴]]和[[铌]]比较，然而，镓不像这些元素，它不会形成矿床。它痕量存在于锌矿石中，<ref name=":1" /><ref>{{cite journal|last1=Frenzel|first1=Max|last2=Hirsch|first2=Tamino|last3=Gutzmer|first3=Jens|date=July 2016|title=Gallium, germanium, indium, and other trace and minor elements in sphalerite as a function of deposit type — A meta-analysis|journal=Ore Geology Reviews|volume=76|pages=52–78|doi=10.1016/j.oregeorev.2015.12.017}}</ref>在铝矿石中的含量略高（~50 ppm），以副产品的形式从这两种矿石中提取。这种缺乏独立矿床的原因是镓的地球化学性质，在大多数与矿床形成相关的过程中都没有显示出强烈的富集性。<ref name=":1" />

[[美国地质调查局]]（USGS）估计已知的铝土矿和锌矿石储量中含有超过100万吨的镓。<ref name="USGSCS2008" /><ref name="USGSCS2006">{{cite web|url= https://minerals.usgs.gov/minerals/pubs/commodity/gallium/myb1-2006-galli.pdf|title= Mineral Yearbook 2006: Gallium|publisher= United States Geological Survey|access-date= 2008-11-20|first= Deborah A.|last= Kramer|archive-date= 2019-01-11|archive-url= https://web.archive.org/web/20190111170745/https://minerals.usgs.gov/minerals/pubs/commodity/gallium/myb1-2006-galli.pdf}}</ref>一些煤{{le|烟道|flue}}[[灰尘]]中含有少量的镓，通常含量低于1%（按重量计）。<ref>{{cite journal|title= Determination of gallium in coal and coal fly ash by electrothermal atomic absorption spectrometry using slurry sampling and nickel chemical modification|author= Xiao-quan, Shan|author2= Wen, Wang|author3= Bei, Wen |journal= Journal of Analytical Atomic Spectrometry|date= 1992|volume= 7|page= 761 |doi= 10.1039/JA9920700761|issue= 5}}</ref><ref>{{cite web|publisher= West Virginia Geological and Economic Survey|date= 2002-03-02|title= Gallium in West Virginia Coals|url= http://www.wvgs.wvnet.edu/www/datastat/te/GaHome.htm|access-date= 2022-01-29|archive-date= 2002-03-11|archive-url= https://web.archive.org/web/20020311013523/http://www.wvgs.wvnet.edu/www/datastat/te/GaHome.htm}}</ref><ref>{{cite journal|author= Font, O|title= Recovery of gallium and vanadium from gasification fly ash|date= 2007|journal= Journal of Hazardous Materials|pmid= 16600480|volume= 139|issue= 3 |doi= 10.1016/j.jhazmat.2006.02.041|pages= 413–23|last2= Querol|first2= Xavier|last3= Juan|first3= Roberto|last4= Casado|first4= Raquel|last5= Ruiz|first5= Carmen R.|last6= López-Soler|first6= Ángel|last7= Coca|first7= Pilar|last8= Peña|first8= Francisco García}}</ref><ref>{{cite journal|title= Elements in Coal Ash and Their Industrial Significance |author= Headlee, A. J. W. |author2= Hunter, Richard G. |pages= 548–551|doi= 10.1021/ie50519a028|volume= 45|date= 1953|journal= Industrial and Engineering Chemistry|issue= 3}}</ref>然而，如果不开采主矿，这些镓是不可提取的（见下文）。因此，镓的产量从根本上取决于铝土矿和锌矿石（和煤）的产量。