Difference between revisions of "User:Physchim62/Helium"
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==Use== | ==Use== | ||
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| + | ! colspan=2 | Total U.S. Consumpton (2009)<br/>52.1 million cubic metres | ||
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| + | The main use of helium is in cryogenics, where helium is essential for temperatures below -429 °F. Such low temperatures are required for [[superconducting magnet]]s to operate; these are used in a variety of applications, including [[NMR spectrometer]]s and [[magnetic resonance imaging]] (MRI) scanners. | ||
==References== | ==References== | ||
{{reflist}} | {{reflist}} | ||
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Helium (symbol: He) is a chemical element, the lightest of the noble gases.
History
Helium is the only element to have been discovered extraterrestrially before being found on Earth, specifically in the Sun. A bright yellow spectral line (λ = 587.49 nm) was first observed by French astronomer Jules Janssen during the eclipse of 18 August 1868, which Janssen observed from Guntur in India, and independently by Norman Lockyer in London on 20 October 1868.[1][2][3] Lockyer, together with English chemist Edward Frankland, showed that the line could not be explained by any known element, and proposed the name helium, from the Greek ἥλιος (helios; the Sun).
Occurrence and production
| Country | Production 106 m3 |
|---|---|
| United States | 122* |
| Algeria | 24 |
| Qatar | 15 |
| Russia | 7 |
| Poland | 2.5 |
| Estimates for 2009 from the U.S. Geological Survey[4] | |
| *U.S. figure includes 42 million cubic metres withdrawn from the federal government stockpile. | |
Helium is the second most common element in the Universe (after hydrogen), accounting for 23% of all atoms. However, the Earth's gravitational field is not strong enough to retain helium in the atmosphere for long periods, and all the Earth's primordial helium is believed to have escaped. The helium currently present on Earth has been formed from the alpha decay of radioactive nuclides: most of this helium escapes to the atmosphere and then into space, but some of it can be trapped underground by impermeable rock formations, often associated with natural gas deposits.
The commercial production of helium is based around its extraction from natural gas, which is economically viable when the helium fraction is greater than about 0.3%. The United States has historically been the predominant producer, although its de novo production is declining and Algeria and Qatar are gaining importance.
The U.S. Bureau of Land Management operates a stockpile of crude helium (~80%) at Cliffside Field, Potter County, Texas, and a crude-helium pipeline from Bushton, Kansas, passing through the Reichel Field (Kansas) and the Keyes Field (Oklahoma) to the Cliffside Field.[5]
Use
| Total U.S. Consumpton (2009) 52.1 million cubic metres | |
|---|---|
| Cryogenics | 32% |
| Pressurizing and purging | 18% |
| Controlled atmospheres | 18% |
| Welding cover gas | 13% |
| Leak detection | 4% |
| Breathing mixtures | 2% |
| Other uses | 13% |
The main use of helium is in cryogenics, where helium is essential for temperatures below -429 °F. Such low temperatures are required for superconducting magnets to operate; these are used in a variety of applications, including NMR spectrometers and magnetic resonance imaging (MRI) scanners.
References
- ↑ Cortie, A. L. Sir Norman Lockyer, 1836–1920. Astrophys. J. 1921, 53 (4), 233–48, <http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1921ApJ....53..233C&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf>.
- ↑ Leggett, Hadley Aug. 18, 1868: Helium Discovered During Total Solar Eclipse; wired.com, August 18, 2009, <http://www.wired.com/thisdayintech/2009/08/dayintech_0818/>. (accessed 18 March 2010).
- ↑ C. R. Hebd. Acad. Sci. Paris 1868, 67, 836–41, <http://gallica.bnf.fr/ark:/12148/bpt6k3024c.image.r=comptes-rendus+hebdomadaires+Acad%C3%A9mie+des+Sciences.f836.langFR>.
- ↑ Helium. In Mineral Commodities Summaries; U.S. Geological Survey, January 2010, <http://minerals.usgs.gov/minerals/pubs/commodity/helium/mcs-2010-heliu.pdf>.
- ↑ Helium. In 2008 Minerals Yearbook; U.S. Geological Survey, October 2009, <http://minerals.usgs.gov/minerals/pubs/commodity/helium/myb1-2008-heliu.pdf>.
