View source for Chemistry:Lignite

{{short description|Soft, brown, combustible, sedimentary rock}}
{{multiple image
 | direction = vertical
 | align = right
 | width = 260 
 | image1 = Lignite-coal.jpg
 | image2 = Braunkohle als Hausbrand.jpg
 | footer = A lignite stockpile (above) and a lignite [[Chemistry:Briquette|briquette]]
}}

'''Lignite''' (derived from [[Social:Latin|Latin]] ''lignum'' meaning 'wood') often referred to as '''brown coal''',<ref name=brit/> is a soft, brown, [[Physics:Combustion|combustible]], [[Earth:Sedimentary rock|sedimentary rock]] formed from naturally compressed [[Earth:Peat|peat]]. It has a [[Chemistry:Carbon|carbon]] content around 25–35%,<ref name=brit/><ref name="useia">{{cite web |title=Coal explained |publisher=Energy Information Administration |url=https://www.eia.gov/energyexplained/coal/ |access-date=2020-09-26}}</ref> and is considered the lowest rank of [[Earth:Coal|coal]] due to its relatively low [[Physics:Heat of combustion|heat content]]. When removed from the ground, it contains a very high amount of [[Earth:Moisture|moisture]] which partially explains its low carbon content. Lignite is mined all around the world and is used almost exclusively as a fuel for steam-electric power generation.

The combustion for lignite produces less heat for the amount of carbon dioxide and sulfur released than other ranks of coal. As a result lignite is the most harmful coal to human health.<ref>{{cite web |title=Lignite coal – health effects and recommendations from the health sector |url=https://www.env-health.org/wp-content/uploads/2018/12/HEAL-Lignite-Briefing-en_web.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.env-health.org/wp-content/uploads/2018/12/HEAL-Lignite-Briefing-en_web.pdf |archive-date=2022-10-09 |url-status=live |publisher=Health and Environment Alliance |date=December 2018}}</ref> Depending on the source, various [[Chemistry:Toxic heavy metal|toxic heavy metal]]s, including [[Physics:Naturally occurring radioactive material|naturally occurring radioactive material]]s, may be present in lignite which are left over in the coal fly ash produced from its combustion, further increasing health risks.<ref>{{Cite web|url=https://www.boell.de/de/2015/06/02/gesundheit-feiner-staub-grosser-schaden|title = Gesundheit: Feiner Staub, großer Schaden}}</ref>

== Characteristics ==
[[File:Lignite mining in Western North Dakota.jpg|thumb|left|Lignite mining, western North Dakota, US (c. 1945)]]

Lignite is brownish-black in color and has a carbon content of 60–70 percent on a dry ash-free basis. However, its [[Chemistry:Coal assay#Moisture|inherent moisture content]] is sometimes as high as 75 percent<ref name=brit>Kopp, Otto C. [https://www.britannica.com/science/lignite "Lignite"] in ''Encyclopædia Britannica''</ref> and its [[Chemistry:Coal assay#Ash|ash]] content ranges from 6–19 percent, compared with 6–12 percent for [[Earth:Bituminous coal|bituminous coal]].<ref>{{cite book | last = Ghassemi | first = Abbas | title = Handbook of Pollution Control and Waste Minimization | publisher = CRC Press | year = 2001 | page = 434 | isbn = 0-8247-0581-5}}</ref> As a result, its carbon content on the as-received basis (i.e., containing both inherent moisture and mineral matter) is typically just 25-35 percent.<ref name="useia"/>

[[File:Garzweiler surface mine, October 2018, -01.jpg|thumb|Strip mining lignite at Tagebau Garzweiler in Germany]]

The energy content of lignite ranges from 10 to 20 MJ/kg (9–17 million [[British thermal unit|BTU]] per [[Short ton|short ton]]) on a moist, mineral-matter-free basis. The energy content of lignite consumed in the United States averages {{nowrap|15 MJ/kg}} (13 million BTU/ton), on the as-received basis.<ref>{{cite web |title=Lignite |url=https://www.eia.gov/tools/glossary/?id=coal |website=Glossary |publisher=U.S. Energy Information Agency |access-date=4 May 2021}}</ref> The energy content of lignite consumed in Victoria, Australia, averages {{nowrap|8.6 MJ/kg}} (8.2 million BTU/ton) on a net wet basis.<ref name="victoria-coal-data-sheet">{{Cite web|url=http://new.dpi.vic.gov.au/__data/assets/pdf_file/0006/37518/Brown-Coal-050710.pdf|title=|archive-url=https://web.archive.org/web/20110317032514/http://new.dpi.vic.gov.au/__data/assets/pdf_file/0006/37518/Brown-Coal-050710.pdf |access-date=30 June 2022|archive-date=2011-03-17 }}</ref>

Lignite has a high content of volatile matter which makes it easier to convert into gas and liquid petroleum products than higher-ranking coals. Unfortunately, its high moisture content and susceptibility to [[Physics:Spontaneous combustion|spontaneous combustion]] can cause problems in transportation and storage. Processes which remove water from brown coal reduce the risk of spontaneous combustion to the same level as black coal, increase the calorific value of brown coal to a black coal equivalent fuel, and significantly reduce the emissions profile of 'densified' brown coal to a level similar to or better than most black coals.<ref>George, A.M.. State Electricity Victoria, Petrographic Report No 17. 1975; Perry, G.J and Allardice, D.J. Coal Resources Conference, NZ 1987 Proc.1, Sec. 4.. Paper R4.1</ref> However, removing the moisture increases the cost of the final lignite fuel.

Lignite rapidly degrades when exposed to air. This process is called ''slacking'' or ''slackening''.<ref name="principal-na"/>

== Uses ==
[[File:Schützender Ring um Lützerath, Demonstration "Alle Dörfer Bleiben – jetzt erst recht!" 30.8.2020 Tagebau Garzweiler.jpg|thumb|Lignite mine in the background of Lützerath, Germany]]
Most lignite is used to generate electricity.<ref name="useia"/> However, small amounts are used in agriculture, in industry, and even, as ''jet'', in jewelry. Its historical use as fuel for home heating has continuously declined and is now of lower importance than its use to generate electricity.

===As fuel===
[[File:Lom ČSA Most Czech Republic 2016 7.jpg|thumb|Layer of lignite for mining in Lom ČSA, Czech Republic]]
Lignite is often found in thick beds located near the surface, making it inexpensive to mine. However, because of its low [[Physics:Energy density|energy density]], tendency to crumble, and typically high moisture content, brown coal is inefficient to transport and is not traded extensively on the world market compared with higher coal grades.<ref name=brit/><ref name="victoria-coal-data-sheet"/> It is often burned in power stations near the mines, such as in Australia's Latrobe Valley and Luminant's Monticello plant and Martin Lake plant in Texas. Primarily because of latent high moisture content and low energy density of brown coal, carbon dioxide emissions from traditional brown-coal-fired plants are generally much higher per megawatt-hour generated than for comparable black-coal plants, with the world's highest-emitting plant being Australia's Hazelwood Power Station<ref>{{cite web
 |url=http://www.wwf.org.au/news/n223/ 
 |title=Hazelwood tops international list of dirty power stations 
 |access-date=2008-10-02 
 |publisher=World Wide Fund for Nature Australia 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20081013091310/http://www.wwf.org.au/news/n223/ 
 |archive-date=2008-10-13 
}}</ref> until its closure in March 2017.<ref>{{cite web
 |url          = http://www.ipplc.com.au/media/newsitem/End-of-generation-at-Hazelwood
 |title        = End of generation at Hazelwood
 |access-date   = 2017-06-30
 |publisher    = Engie
 |archive-url  = https://web.archive.org/web/20170331114514/http://www.ipplc.com.au/media/newsitem/End-of-generation-at-Hazelwood
 |archive-date = 2017-03-31
 |url-status     = dead
}}</ref> The operation of traditional brown-coal plants, particularly in combination with strip mining, is politically contentious due to environmental concerns.<ref>{{Cite web
|url=http://www.vic.greens.org.au/news/media-releases-2006/the-greens-won-t-line-up-for-dirty-brown-coal-in-the-valley
|title=The Greens Won't Line Up For Dirty Brown Coal In The Valley
|publisher=Australian Greens Victoria
|date=2006-08-18
|access-date=2007-06-28
}}</ref><ref>{{cite web
|url=http://www.ens-newswire.com/ens/may2004/2004-05-28-02.asp
|title=Greenpeace Germany Protests Brown Coal Power Stations
|publisher=Environment News Service
|date=2004-05-28
|access-date=2007-06-28
|archive-url = https://web.archive.org/web/20070930203414/http://www.ens-newswire.com/ens/may2004/2004-05-28-02.asp |archive-date = 2007-09-30}}</ref>

The German Democratic Republic relied extensively on lignite to become energy [[Philosophy:Autarky|self-sufficient]], and eventually obtained 70% of its energy requirements from lignite.<ref>{{cite web |last1=Irfan |first1=Ulmair |title=How East Germany Cleaned Up Dirty Power |url=https://www.scientificamerican.com/article/how-east-germany-cleaned-up-dirty-power/ |website=Scientific American |publisher=Springer Nature America, Inc. |access-date=4 May 2021 |date=3 November 2014}}</ref> Lignite was also an important chemical industry feedstock via [[Chemistry:Bergius process|Bergius process]] or Fischer-Tropsch synthesis in lieu of petroleum,<ref>{{cite news |title=Liquid fuel revival |url=https://www.soci.org/Chemistry-and-Industry/CnI-Data/2009/22/Liquid-fuel-revival |access-date=4 May 2021 |work=Chemistry and Industry |agency=SCI |issue=22 |date=2009}}</ref> which had to be imported for [[Finance:Hard currency|hard currency]] following a change in policy by the [[Place:Soviet Union|Soviet Union]] in the 1970s, which had previously delivered petroleum at below market rates.<ref name="history-germany">{{cite web |title=The history of energy in Germany |url=https://www.planete-energies.com/en/medias/saga-energies/history-energy-germany |website=Planete energies |publisher=Total Foundation |access-date=4 May 2021 |date=29 April 2015}}</ref> East German scientists even converted lignite into [[Chemistry:Coke (fuel)|coke]] suitable for metallurgical uses (high temperature lignite coke) and much of the railway network was dependent on lignite either through [[Engineering:Steam locomotive|steam trains]] or [[Engineering:Railway electrification|electrified]] lines mostly fed with lignite derived power.<ref name="history-germany"/> As per the table below, East Germany was the largest producer of lignite for much of its existence as an independent state.

In 2014, about 12 percent of Germany's energy and, specifically, 27 percent of Germany's electricity came from lignite power plants,<ref>{{cite news|url=https://www.bmwi.de/BMWi/Redaktion/PDF/E/energiestatistiken-energiegewinnung-energieverbrauch,property=pdf,bereich=bmwi2012,sprache=de,rwb=true.pdf|title=Statistics on energy production in Germany 2014, Department of Energy (in german, lignite = "Braunkohle")|date=2014-10-01|access-date=2015-12-10|archive-url=https://web.archive.org/web/20151206115815/http://www.bmwi.de/BMWi/Redaktion/PDF/E/energiestatistiken-energiegewinnung-energieverbrauch,property=pdf,bereich=bmwi2012,sprache=de,rwb=true.pdf|archive-date=2015-12-06|url-status=dead}}</ref> while in 2014 in Greece, lignite provided about 50 percent of its power needs. Germany has announced plans to [[Earth:Fossil fuel phase-out|phase out lignite]] by 2038 at the latest.<ref>{{Cite web|url=https://www.tagesschau.de/wirtschaft/kohlekompromiss-101.html|title = Interview zum Kohlekompromiss: "Damit ist es nicht getan"|website=Tagesschau.de}}</ref><ref>{{Cite web|url=https://www.erneuerbareenergien.de/was-der-kohlekompromiss-fuer-deutschland-bedeutet|title=Was der Kohlekompromiss für Deutschland bedeutet|website=Erneuerbareenergien.de|date=13 August 2019}}</ref><ref>{{Cite web|url=https://www.zdf.de/uri/c01c31fc-36f2-48c4-8c12-8fc92b53b458|title=Teurer Kohlekompromiss|website=Zdf.de|access-date=30 June 2022}}</ref><ref>{{Cite web|url=https://www.ksta.de/politik/kommentar-zum-kohleausstieg-der-kohlekompromiss-ist-ein-meisterstueck-31939930?cb=1607428307426|title=Kommentar zum Kohleausstieg: Der Kohlekompromiss ist ein Meisterstück|website=Ksta.de|date=26 January 2019}}</ref> Greece has confirmed that the last coal plant will be shut in 2025 after receiving pressure from the [[Social:European Union|European Union]]<ref>{{Cite web|url=https://www.euractiv.com/section/climate-environment/news/greece-confirms-last-coal-plant-will-be-shut-in-2025/|title=Greece confirms last coal plant will be shut in 2025|website=Euractiv.com|date=26 April 2021}}</ref> and plans to heavily invest in [[Engineering:Renewable energy|renewable energy]].<ref>{{Cite web|url=https://www.skai.gr/news/environment/skrekas-proetoimazoume-kai-sxediazoume-tin-prasini-politiki-tis-xoras|title = Σκρέκας: Προετοιμάζουμε και σχεδιάζουμε την πράσινη πολιτική της χώρας &#124; ΣΚΑΪ|website=Skai.gr|date = 18 May 2021}}</ref>

=== Home heating===
Lignite was and is used as a replacement for or in combination with firewood for home heating. It is usually pressed into briquettes for that use.<ref>{{cite book |last1=Francis |first1=Wilfrid |title=Fuels and fuel technology : a summarized manual |date=1980 |publisher=Pergamon Press |location=Oxford |isbn=9781483147949 |pages=4–5 |edition=2d (SI)}}</ref><ref>{{cite journal |last1=Thuβ |first1=U. |last2=Popp |first2=P. |last3=Ehrlich |first3=Chr. |last4=Kalkoff |first4=W.-D. |title=Domestic lignite combustion as source of polychlorodibenzodioxins and -furans (PCDD/F) |journal=Chemosphere |date=July 1995 |volume=31 |issue=2 |pages=2591–2604 |doi=10.1016/0045-6535(95)00132-R|bibcode=1995Chmsp..31.2591T }}</ref> Due to the smell it gives off when burned, lignite was often seen as a fuel for poor people compared to higher value hard coals. In Germany, briquettes are still readily available to end consumers in home improvement stores and supermarkets.<ref>{{Cite web|url=https://www.obi.de/search/briketts/#/|title = Briketts kaufen bei |website=Obi.de}}</ref><ref>{{Cite web|url=https://www.hornbach.de/shop/suche/sortiment/briketts|title = Briketts kaufen bei|website=Hornbach.de}}</ref><ref>{{Cite web|url=https://shop.rewe.de/p/braunkohlebriketts-10kg/4791800|title=Braunkohlebriketts 10kg bei REWE online bestellen!|website=Shop.rewe.de|access-date=30 June 2022}}</ref><ref>{{Cite web|url=https://www.bauhaus.info/brennholz-briketts/c/10001327|title = Briketts kaufen bei Bauhaus|website=Bauhaus.info}}</ref>

===In agriculture {{anchor|in agriculture}} ===
An environmentally beneficial use of lignite is in agriculture. Lignite may have value as an environmentally benign soil amendment, improving cation exchange and phosphorus availability in soils while reducing availability of heavy metals,<ref>{{cite journal |last1=Kim Thi Tran |first1=Cuc |last2=Rose |first2=Michael T. |last3=Cavagnaro |first3=Timothy R. |last4=Patti |first4=Antonio F. |title=Lignite amendment has limited impacts on soil microbial communities and mineral nitrogen availability |journal=Applied Soil Ecology |date=November 2015 |volume=95 |pages=140–150 |doi=10.1016/j.apsoil.2015.06.020|bibcode=2015AppSE..95..140K }}</ref><ref>{{cite journal |last1=Li |first1=Changjian |last2=Xiong |first2=Yunwu |last3=Zou |first3=Jiaye |last4=Dong |first4=Li |last5=Ren |first5=Ping |last6=Huang |first6=Guanhua |title=Impact of biochar and lignite-based amendments on microbial communities and greenhouse gas emissions from agricultural soil |journal=Vadose Zone Journal |date=March 2021 |volume=20 |issue=2 |doi=10.1002/vzj2.20105|bibcode=2021VZJ....2020105L |doi-access=free }}</ref> and may be superior to commercial K humates.<ref>{{cite journal |last1=Lyons |first1=Graham |last2=Genc |first2=Yusuf |title=Commercial Humates in Agriculture: Real Substance or Smoke and Mirrors? |journal=Agronomy |date=28 October 2016 |volume=6 |issue=4 |pages=50 |doi=10.3390/agronomy6040050|doi-access=free }}</ref> Lignite fly ash produced by combustion of lignite in power plants may also be valuable as a soil amendment and fertilizer.<ref>{{cite journal |last1=Ram |first1=Lal C. |last2=Srivastava |first2=Nishant K. |last3=Jha |first3=Sangeet K. |last4=Sinha |first4=Awadhesh K. |last5=Masto |first5=Reginald E. |last6=Selvi |first6=Vetrivel A. |title=Management of Lignite Fly Ash for Improving Soil Fertility and Crop Productivity |journal=Environmental Management |date=September 2007 |volume=40 |issue=3 |pages=438–452 |doi=10.1007/s00267-006-0126-9|pmid=17705037 |bibcode=2007EnMan..40..438R |s2cid=1257174 }}</ref> However, rigorous studies of the long-term benefits of lignite products in agriculture are lacking.<ref>{{cite journal |last1 = Patti |first1=Antonio |last2=Rose |first2=Michael |last3=Little |first3=Karen |last4=Jackson |first4=Roy |last5=Cavagnaro |first5=Timothy |title = Evaluating Lignite-Derived Products (LDPs) for Agriculture – Does Research Inform Practice?  |journal = EGU General Assembly Conference Abstracts |year = 2014  |page=10165 |url = https://ui.adsabs.harvard.edu/abs/2014EGUGA..1610165P |access-date=4 May 2021 |bibcode=2014EGUGA..1610165P}}</ref>

Lignite may also be used for the cultivation and distribution of biological control microbes that suppress plant pests. The carbon increases the organic matter in the soil while the biological control microbes provide an alternative to chemical pesticides.<ref>{{cite journal|last1=Jones|first1=Richard|last2=Petit|first2=R|last3=Taber|first3=R|title=Lignite and stillage:carrier and substrate for application of fungal biocontrol agents to soil|doi=10.1094/Phyto-74-1167|journal=Phytopathology|date=1984|volume=74|issue=10|pages=1167–1170}}</ref>

''[[Chemistry:Leonardite|Leonardite]]'' is a soil conditioner rich in humic acids that is formed by natural oxidation when lignite comes in contact with air.<ref name ="Youngs">{{Cite web|url=http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/07_1_CINCINNATI_01-63_0012.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/07_1_CINCINNATI_01-63_0012.pdf |archive-date=2022-10-09 |url-status=live|title=Youngs, R.W. & Frost, C.M. 1963. Humic acids from leonardite – a soil conditioner and organic fertilizer. Ind. Eng. Chem., 55, 95–99|access-date=30 June 2022}}</ref> The process can be replicated artificially on a large scale. <ref>{{cite journal |last1=Gong |first1=Guanqun |last2=Xu |first2=Liangwei |last3=Zhang |first3=Yingjie |last4=Liu |first4=Weixin |last5=Wang |first5=Ming |last6=Zhao |first6=Yufeng |last7=Yuan |first7=Xin |last8=Li |first8=Yajun |title=Extraction of Fulvic Acid from Lignite and Characterization of Its Functional Groups |journal=ACS Omega |date=3 November 2020 |volume=5 |issue=43 |pages=27953–27961 |doi=10.1021/acsomega.0c03388|pmid=33163778 |pmc=7643152 }}</ref> The less matured xyloid (wood-shaped) lignite also contains high amounts of humic acid.<ref Name="Mackie"/>

=== In drilling mud {{anchor|in industry}} ===
Reaction with [[Chemistry:Quaternary ammonium cation|quaternary amine]] forms a product called amine-treated lignite (ATL), which is used in drilling mud to reduce fluid loss during drilling.<ref>{{cite journal |last1=Elgibaly |first1=A. |last2=Farahat |first2=M. |last3=Abd El Nabbi |first3=M. |title=The Optimum Types and Characteristics of Drilling Fluids Used During Drilling in The Egyption Western Desert |journal=Journal of Petroleum and Mining Engineering |date=1 December 2018 |volume=20 |issue=1 |pages=89–100 |doi=10.21608/jpme.2018.40453|doi-access=free }}</ref>

===As an industrial adsorbent===
Lignite may have potential uses as an industrial adsorbent. Experiments show that its adsorption of [[Chemistry:Methylene blue|methylene blue]] falls within the range of [[Physics:Activated carbon|activated carbon]]s currently used by industry.<ref>{{cite journal |last1=Qi |first1=Ying |last2=Hoadley |first2=Andrew F.A. |last3=Chaffee |first3=Alan L. |last4=Garnier |first4=Gil |title=Characterisation of lignite as an industrial adsorbent |journal=Fuel |date=April 2011 |volume=90 |issue=4 |pages=1567–1574 |doi=10.1016/j.fuel.2011.01.015}}</ref>

===In jewellery {{anchor|in jewelry}} ===
[[Earth:Jet (lignite)|Jet]] is a form of lignite that has been used as a gemstone.<ref name="Glossary2005">{{cite book | title=Glossary of Geology |edition=5th | publisher=American Geological Institute |editor-last=Neuendorf |editor-first=K. K. E. Jr. |editor2-last=Mehl |editor2-first=J. P. |editor3-last=Jackson |editor3-first=J. A.| year=2005 | location=Alexandria, Virginia | pages=344}}</ref> The earliest jet artifacts date to 10,000 BCE<ref name="botfly">{{cite web|url=http://donsmaps.com/petersfels.html|title=Venus figures from Petersfels|access-date=9 August 2016|url-status=live|archive-url=https://web.archive.org/web/20160929213049/http://donsmaps.com/petersfels.html|archive-date=29 September 2016}}</ref> and jet was used extensively in necklaces and other ornamentation in Britain from the [[History:Neolithic|Neolithic]] until the end of Roman Britain.<ref name=RomanJet8>{{cite book |last=Allason-Jones |first=Lindsay  |date=1996|title=Roman Jet in the Yorkshire Museum|publisher=The Yorkshire Museum |pages=8–11 |isbn=0905807170}}</ref> Jet experienced a brief revival in Victorian Britain.<ref name=MullerH59>{{cite book |last=Muller |first=Helen |date=1987 |title=Jet|publisher=Butterworths |pages=59–63 |isbn=0408031107}}</ref>

== Geology ==
[[File:Canal Run shadows (5179305812).jpg|thumb|Okefenokee Swamp, a modern peat-forming swamp]]
[[File:U S Geological Survey Circular 1143 Lignite Structure.png|thumb|Partial molecular structure of a lignin-derived organic molecule in lignite]]

Lignite begins as an accumulation of partially decayed plant material, or peat. Peat accumulates most readily in areas where there is ample moisture, slow subsidence of the land surface, and lack of disturbance by rivers or oceans. Peat swamps are otherwise found in a wide variety of climates and geographical settings. Under these conditions, the area remains saturated with water, which covers dead plant material and protects it from degradation by atmospheric oxygen. Anaerobic bacteria may continue to degrade the peat, but this process is slow, particularly in acid water. Once the peat is buried by other sediments, biological degradation essentially comes to a halt, and further changes are a result of increased temperature and pressure from burial.<ref>{{cite journal |last1=Schweinfurth |first1=Stanley P. |last2=Finkelman |first2=Robert P. |title=Coal – A complex natural resource |journal=U.S. Geological Survery Circular |date=2002 |volume=1143 |doi=10.3133/cir1143|doi-access=free |hdl=2027/umn.31951d02181642b |hdl-access=free }}</ref>

Lignite forms from peat that has not experienced deep burial and heating. It forms at temperatures below {{convert|100|C||}},<ref name=brit/> primarily by biochemical degradation. This includes humification, in which microorganisms extract hydrocarbons from the peat and humic acids are formed. The humic acids make the environment more acidic, which slows the rate of further bacterial decay. Humification is still incomplete in lignite, coming to completion only when the coal reaches sub-bituminous rank.<ref>{{cite web |title=Coal types, formation, and methods of mining |url=http://epcamr.org/home/content/reference-materials/coal-types-formation-and-methods-of-mining/ |website=Eastern Pennsylvania Coalition for Abandoned Mine Reclamation |access-date=5 May 2021 |date=2016}}</ref> The most characteristic chemical change in the organic material during formation of lignite is the sharp reduction in the number of C=O and C-O-R functional groups.<ref>{{cite journal |last1=Ibarra |first1=JoséV. |last2=Muñoz |first2=Edgar |last3=Moliner |first3=Rafael |title=FTIR study of the evolution of coal structure during the coalification process |journal=Organic Geochemistry |date=June 1996 |volume=24 |issue=6–7 |pages=725–735 |doi=10.1016/0146-6380(96)00063-0|bibcode=1996OrGeo..24..725I }}</ref>

Lignite deposits are typically younger than higher-ranked coals, with the majority of them having formed during the [[Earth:Tertiary|Tertiary]] period.<ref name=brit/>

== Extraction ==
Lignite is often found in thick beds located near the surface.<ref name=brit/><ref name="victoria-coal-data-sheet"/> These are inexpensive to extract using various forms of surface mining, though this can result in serious environmental damage.<ref name="NGcoal">{{cite web |last1=Turgeon |first1=Andrew |last2=Morse |first2=Elizabeth |title=Coal |date=22 December 2012 |url=https://www.nationalgeographic.org/encyclopedia/coal/ |publisher=National Geographic |access-date=25 September 2021}}</ref> Regulations in the United States and other countries require that land that is surface mined must be restored to its original productivity once mining is complete.<ref name="BNIreclaim">{{cite web |title=Reclamation Process |url=http://www.bnicoal.com/about/reclamation-process |website=Mining Lignite Coal for our Energy Future |publisher=BNI Coal |access-date=25 September 2021}}</ref>

Strip mining of lignite in the United States begins with [[Earth:Boring (earth)|drilling]] to establish the extent of the subsurface beds. [[Earth:Topsoil|Topsoil]] and [[Earth:Subsoil|subsoil]] must be properly removed and either used to reclaim previously mined-out areas or stored for future reclamation. [[Engineering:Excavator|Excavator]] and truck overburden removal prepares the area for [[Engineering:Dragline excavator|dragline]] overburden removal to expose the lignite beds. These are broken up using specially equipped tractors (''coal ripping'') and then loaded into bottom dump trucks using [[Engineering:Loader (equipment)|front loaders]].<ref name="BNIprocess">{{cite web |title=Mining Process |url=http://www.bnicoal.com/about/mining-process |website=Mining Lignite Coal for our Energy Future |publisher=BNI Coal |access-date=25 September 2021}}</ref>

Once the lignite is removed, restoration involves grading the mine spoil to as close an approximation as practical of the original ground surface (Approximate Original Contour or AOC). Subsoil and topsoil are restored and the land reseeded with various grasses. In North Dakota, a [[Finance:Performance bond|performance bond]] is held against the mining company for at least ten years after the end of mining operations to guarantee that the land has been restored to full productivity.<ref name="BNIreclaim"/> A bond (not necessary in this form) for mine reclamation is required in the US by the Surface Mining Control and Reclamation Act of 1977.<ref>{{cite web |title=Reclamation Bonds |url=https://www.osmre.gov/resources/reclamation-bonds |website= Office of Surface Mining Reclamation and Enforcement}}</ref>

== Resources and reserves==

=== List of countries by lignite reserves ===

{|class = "wikitable sortable"
|+Top Ten Countries by lignite reserves (2020)<ref name="Sönnichsen">{{cite web|url=https://www.statista.com/statistics/264778/countries-with-the-largest-soft-brown-coal-reserves/|title=Leading countries based on lignite reserves 2020|language=en|publisher=[[Company:Statista|Statista]]|date=February 2022|access-date=2022-07-30}}</ref>
|-
! rowspan = "1" | Countries
! rowspan = "1" | Lignite reserves (millions of tons)
|-
| Russia
| 90447
|-
|| Australia
|| 73865
|-
|| Germany
|| 35700
|-
|| United States
|| 29910
|-
|| Turkey
|| 19320<ref>While the Statista review reports 10975 million tonnes for Turkey, the 2005-2019 surveys of the Mineral Research and Exploration General Directorate of Turkey has almost doubled this value. {{cite web | url = https://www.mta.gov.tr/v3.0/arastirmalar/komur-arama-arastirmalari | language = tr | accessdate = 2022-07-30 | title = Kömür Arama Araştırmaları | publisher = MTA Genel Müdürlüğü | trans-title = Coal Surveying Studies}}</ref>
|-
|| Indonesia
|| 14746
|-
|| China
|| 8250
|-
|| Republic of Kosovo
|| 7112
|-
|| New Zealand
|| 6750
|-
|| Poland
|| 5752
|}

===Australia===
The Latrobe Valley in Victoria, {{wipe|Australia}}, contains estimated reserves of some 65 billion tonnes of brown coal.<ref name=Gov>Department of Primary Industries, Victorian Government, Australia, ‘Victoria Australia: A Principle Brown Coal Province’ (Fact Sheet, Department of Primary Industries, July 2010).</ref> The deposit is equivalent to 25 percent of known world reserves. The coal seams are up to 98 metres thick, with multiple coal seams often giving virtually continuous brown coal thickness of up to 230 metres. Seams are covered by very little overburden (10 to 20 metres).<ref name=Gov/>

A partnership led by [[Company:Kawasaki Heavy Industries|Kawasaki Heavy Industries]] and backed by the governments of Japan and Australia has begun extracting hydrogen from brown coal. The liquefied hydrogen will be shipped via the transporter ''Suiso Frontier'' to Japan.<ref>{{cite web |title=Kawasaki Heavy says liquefied hydrogen carrier departs Japan for Australia |url=https://www.reuters.com/world/asia-pacific/kawasaki-heavy-says-liquefied-hydrogen-carrier-departs-japan-australia-2021-12-24/ |website=Asia Pacific |publisher=Reuters |access-date=24 December 2021 |date=24 December 2021}}</ref>

===North America===
The largest lignite deposits in North America are the Gulf Coast lignites and the Fort Union lignite field. The Gulf Coast lignites are located in a band running from {{wipe|Texas}} to Alabama roughly parallel to the Gulf Coast. The Fort Union lignite field stretches from North Dakota to Saskatchewan. Both are important commercial sources of lignite.<!-- as of 1995--><ref name="principal-na">{{cite journal |editor1-last=Schobert |editor1-first=Harold H. |title=Chapter 1 The principal lignite deposits of North America |journal=Coal Science and Technology |date=1995 |volume=23 |pages=1–50 |doi=10.1016/S0167-9449(06)80002-9|isbn=9780444898234 }}</ref>

== Types == <!--xyloid lignite, compact lignite, and perfect lignite; redirect here-->

Lignite can be separated into two types. The first is xyloid lignite or [[Biology:Fossil wood|fossil wood]] and the second form is the compact lignite or perfect lignite.

Although xyloid lignite may sometimes have the tenacity and the appearance of ordinary wood, it can be seen that the combustible woody tissue has experienced a great modification. It is reducible to a fine powder by [[Chemistry:Trituration|trituration]], and if submitted to the action of a weak solution of [[Chemistry:Potash|potash]], it yields a considerable quantity of humic acid.<ref Name="Mackie">{{cite book | last =Mackie | first =Samuel Joseph | title =The Geologist | publisher =Reynolds | year = 1861 | location = Original from Harvard University | pages =197–200 | url =https://books.google.com/books?id=SzsFAAAAYAAJ&q=Xyloid+coal&pg=PA199}}</ref> [[Chemistry:Leonardite|Leonardite]] is an oxidized form of lignite, which also contains high levels of humic acid.<ref>{{Cite book|url=https://books.google.com/books?id=oIh9_U0Fo_cC&dq=leonardite+humic+acid+extractable&pg=PA26|title=Humic Matter in Soil and the Environment: Principles and Controversies|first=Kim H.|last=Tan|date=22 April 2003|publisher=CRC Press|isbn=9780203912546 |access-date=30 June 2022|via=Google Books}}</ref>

Jet is a hardened, [[Earth:Gemstone|gem-like]] form of lignite used in various types of jewelry.<ref name="Glossary2005"/><!-- Yes, this duplicates infomation in the Uses section. It's relevant to both.-->

== Production ==
 {{wipe|Germany}} is the largest producer of lignite,<ref name = "BGR, 2015" /> followed by {{wipe|China}}, {{wipe|Russia}}, and {{wipe|United States}}.<ref name = "Appunn, CEW, 2018" /> Lignite accounted for 8% of all U.S. coal production in 2019.<ref name="useia"/>
{| class="wikitable sortable" style="text-align: center;"
|+Lignite mined in millions of [[Tonne|tonne]]s
! Country or territory
! data-sort-type="number" | 1970
! data-sort-type="number" | 1980
! data-sort-type="number" | 1990
! data-sort-type="number" | 2000
! data-sort-type="number" | 2010
! data-sort-type="number" | 2011
! data-sort-type="number" | 2012
! data-sort-type="number" | 2013
! data-sort-type="number" | 2014
! data-sort-type="number" | 2015
|-
| align=left | {{Flag|East Germany}} || 261|| 258.1 || 280 ||colspan="7"| {{efn|name=fn1}} 
|-
| align=left | {{Flag|Germany}} || 108{{efn|name=fn2}} || 129.9{{efn|name=fn2}} || 107.6{{efn|name=fn2}} || 167.7 || 169 || 176.5 || 185.4 || 183 || 178.2 || 178.1
|-
| align=left | {{Flag|China}} || – <!--13.0--> || 24.3 || 45.5 || 47.7 || 125.3 || 136.3 || 145 || 147 || 145 || 140
|-
| align=left | {{Flag|Russia}} || 145{{efn|name=fn3}} || 141{{efn|name=fn3}} || 137.3{{efn|name=fn3}} || 87.8 || 76.1 || 76.4 || 77.9 || 73 || 70 || 73.2
|-
| align=left | {{Flag|Kazakhstan}} ||rowspan="2" colspan="3"| {{efn|name=fn4}} || 2.6 || 7.3 || 8.4 || 5.5 || 6.5 || 6.6 || –
|-
|align=left | {{flag|Uzbekistan}} || 2.5 || 3.4 || 3.8 || 3.8 || – || – || –
|-
| align=left | {{Flag|United States}} || 5 || 42.8 || 79.9 || 77.6 || 71.0 || 73.6 || 71.6 || 70.1 || 72.1 || 64.7
|-
| align=left | {{Flag|Poland}} || – <!--32.8--> || 36.9 || 67.6 || 59.5 || 56.5 || 62.8 || 64.3 || 66 || 63.9 || 63.1
|-
| align=left | {{Flag|Turkey}} || – <!--4.4--> || 14.5 || 44.4 || 60.9 || 70.0 || 72.5 || 68.1 || 57.5 || 62.6 || 50.4
|-
| align=left | {{Flag|Australia}} || – <!--24.2--> || 32.9 || 46 || 67.3 ||68.8 || 66.7 || 69.1 || 59.9 || 58.0 || 63.0
|-
| align=left | {{Flag|Greece}} || – <!--8.1--> || 23.2 || 51.9 || 63.9 || 56.5 || 58.7 || 61.8 || 54 || 48 || 46
|-
| align=left | {{Flag|India}} || – || 5 || 14.1 || 24.2 || 37.7 || 42.3 || 43.5 || 45 || 47.2 || 43.9
|-
| align=left | {{Flag|Indonesia}} || – || – || – || – ||40.0 || 51.3 || 60.0 || 65.0 || 60.0 || 60.0
|-
| align=left | {{Flag|Czechoslovakia}} || 82 || 87 || 71 ||colspan="7"| {{efn|name=fn5}} 
|-
| align=left | {{Flag|Czech Republic}} ||rowspan="2" colspan="3"| {{efn|name=fn6}} || 50.1 || 43.8 || 46.6 || 43.5 || 40 || 38.3 || 38.3
|-
| align=left | {{Flag|Slovakia}} || 3.7 || 2.4 || 2.4 || 2.3 || – || – || –
|-
| align=left | {{Flag|Yugoslavia}} || – <!--26--> || 33.7 || 64.1 ||colspan="7"| {{efn|name=fn7}} 
|-
| align=left | {{Flag|Serbia}} ||rowspan="6" colspan="3"| {{efn|name=fn8}} || 35.5{{efn|name=fn9}} || 37.8 || 40.6 || 38 || 40.1 || 29.7 || 37.3
|-
| align=left | {{Flag|Kosovo}} || {{efn|name=fn10}} || 8.7{{efn|name=fn11}} || 9{{efn|name=fn11}} || 8.7{{efn|name=fn11}} || 8.2{{efn|name=fn11}} || 7.2{{efn|name=fn11}} || 8.2{{efn|name=fn11}}
|-
| align=left | {{Flag|North Macedonia}} || 7.5 || 6.7 || 8.2 ||7.5 || – || – || – 
|-
| align=left | {{Flag|Bosnia and Herzegovina}} || 3.4 || 11 || 7.1 || 7 || 6.2 || 6.2 || 6.5
|-
| align=left | {{Flag|Slovenia}} || 3.7 || 4|| 4.1 || 4 ||  – || – || – 
|-
| align=left | {{Flag|Montenegro}} || {{efn|name=fn10}} || 1.9 || 2 || 2 ||  – || – || – 
|-
| align=left | {{Flag|Romania}} || – || 26.5 || 33.7 || 29 || 31.1 || 35.5 || 34.1 || 24.7|| 23.6 || 25.2
|-
| align=left | {{Flag|Bulgaria}} || – || 30 ||31.5 || 26.3 || 29.4 || 37.1 || 32.5 || 26.5 || 31.3 || 35.9
|-
| align=left | {{Flag|Albania}} || – || 1.4 || 2.1 || 30 || 14 || 9 || 20 ||  – || – || – 
|-
| align=left | {{flag|Thailand}} || – || 1.5 || 12.4 || 17.8 || 18.3 || 21.3 || 18.3 || 18.1 || 18 || 15.2
|-
| align=left | {{Flag|Mongolia}} || – || 4.4 || 6.6 || 5.1 || 8.5 || 8.3 || 9.9 || – || – || – 
|-
| align=left | {{Flag|Canada}} || – || 6 || 9.4 || 11.2 || 10.3 || 9.7 || 9.5 || 9.0 || 8.5 || 10.5
|-
| align=left | {{Flag|Hungary}} || – || 22.6 || 17.3 || 14 || 9.1 || 9.6 || 9.3 || 9.6 || 9.6 || 9.3
|-
| align=left | {{Flag|North Korea}} || – || 10 || 10.6 || 7.2 || 6.7 || 6.8 || 6.8 || 7 || 7 || 7
|-
! colspan=11 style="font-weight: normal; font-size: 0.85em; text-align: left; padding: 6px 2px 4px 4px;" |Source: [[Organization:World Coal Association|World Coal Association]]<ref>{{cite web|url=http://www.worldcoal.org/resources/statistics/|title= Resources|publisher=[[Organization:World Coal Association|World Coal Association]]|date=2014|access-date=2015-12-22}}</ref>{{·}}U.S. Energy Information Administration<ref>{{cite web|url=http://www.eia.gov/cfapps/ipdbproject/iedindex3.cfm?tid=1&pid=14&aid=1&cid=regions&syid=1980&eyid=2012&unit=TST|title=Production of Lignite Coal |publisher=U.S. Energy Information Administration|date=2012|access-date=2015-12-23}}</ref>{{·}}BGR bund.de Energiestudie 2016<ref>{{Cite web |url=http://www.bgr.bund.de/DE/Themen/Energie/Downloads/Energiestudie_2016_Tabellen.xlsx?__blob=publicationFile&v=1 |title=Archived copy |access-date=2017-04-19 |archive-date=2017-10-20 |archive-url=https://web.archive.org/web/20171020084706/http://www.bgr.bund.de/DE/Themen/Energie/Downloads/Energiestudie_2016_Tabellen.xlsx?__blob=publicationFile&v=1 |url-status=dead }}</ref>{{·}}1970 data from World Coal (1987)<ref>{{cite book|last=Gordon|first=Richard|date=1987|title=World coal: economics, policies and prospects|pages=44|location=Cambridge|publisher=Cambridge University Press|isbn=0521308275|oclc=506249066}}</ref>

– ''no data available''
|}

{{notelist|refs=
{{efn|name=fn1|[[Place:East Germany|East Germany]] became a part of {{wipe|Germany}} as a result of German reunification in 1990.}}
{{efn|name=fn2|Data prior to 2000 are for West Germany only.}}
{{efn|name=fn3|Data prior to 2000 represent the [[Place:Soviet Union|Soviet Union]].}}
{{efn|name=fn4|Country was a part of the [[Place:Soviet Union|Soviet Union]] during this time.}}
{{efn|name=fn5|[[Place:Czechoslovakia|Czechoslovakia]] dissolved in 1993.}}
{{efn|name=fn6|Country was a part of [[Place:Czechoslovakia|Czechoslovakia]] during this time.}}
{{efn|name=fn7|[[Place:Yugoslavia|Yugoslavia]] broke up in a process that concluded in 1992.}}
{{efn|name=fn8|Country was a part of [[Place:Yugoslavia|Yugoslavia]] during this time.}}
{{efn|name=fn9|2000 data is for [[Place:Federal Republic of Yugoslavia|Federal Republic of Yugoslavia]].}}
{{efn|name=fn10|Country was a part of [[Place:Federal Republic of Yugoslavia|Federal Republic of Yugoslavia]] during this time.}}
{{efn|name=fn11|Albanians unilaterally declared independence from Serbia, but the country it is not member of UN and its status is heavily disputed.}}
}}

== Gallery ==
<gallery class="center" mode="packed" heights="220px">
File:Braunkohletagebau Schleenhain.jpg|Open-pit United Schleenhain coal mine in Saxony, Germany
</gallery>

== See also ==

* Rheinisches Braunkohlerevier
* NLC India Limited
{{Div col|colwidth=26em}}
* {{annotated link|Chemistry:Coal assay}}
* {{annotated link|Physics:Energy value of coal}}
* {{annotated link|Engineering:Karrick process}}
* {{annotated link|Engineering:Kemper Project}}
* {{annotated link|Orders of magnitude (specific energy)}}
* {{annotated link|Chemistry:Torrefaction}}
* {{annotated link|Organization:International Humic Substances Society}}
{{Div col end}}

== References ==
{{Reflist|30em|refs=
<ref name = "BGR, 2015" >{{ Cite web | url = https://www.bgr.bund.de/DE/Themen/Min_rohstoffe/Downloads/Rohsit-2015.pdf?__blob=publicationFile&v=3 | title = Deutschland ‒Rohstoffsituation 2015 | access-date = 6 July 2019 | date = 1 November 2016 | website = Bundesanstalt für Geowissenschaften und Rohstoffe | language = de | format = pdf | archive-url = https://web.archive.org/web/20190706225443/https://www.bgr.bund.de/DE/Themen/Min_rohstoffe/Downloads/Rohsit-2015.pdf?__blob=publicationFile&v=3 | archive-date = 6 July 2019  | df = dmy-all }}</ref>
 <ref name = "Appunn, CEW, 2018" >{{ Cite web | url = https://www.cleanenergywire.org/factsheets/germanys-three-lignite-mining-regions | title = Germany's three lignite mining regions | access-date = 5 July 2019 | first = Kerstine | last = Appunn | date = 7 August 2018 | website = The Clean Energy Wire | quote = Germany has been the largest lignite producer in the world since the beginning of industrial lignite mining. It still is, followed by China, Russia, and the United States. The softer and moister lignite (also called brown or soft coal) has a lower calorific value than hard coal and can only be mined in opencast operations. When burned, it is more CO2 intensive than hard coal. | archive-url = https://web.archive.org/web/20181126142844/https://www.cleanenergywire.org/factsheets/germanys-three-lignite-mining-regions | archive-date = 26 November 2018  | df = dmy-all }}</ref>
 }}

== External links ==
*{{cite web|url=https://yearbook.enerdata.net/coal-and-lignite-world-consumption.html|title=Coal and lignite domestic consumption |publisher=Global Energy Statistical Yearbook |year=2016 }}
*[http://www.geographyinaction.co.uk/Issues/Lignite.html Geography in action – an Irish case study]
*[http://www.geographyinaction.co.uk/Assets/Photo_albums/Eight/pages/Lignite.html Photograph of lignite]
*[https://web.archive.org/web/20091022231254/http://www.cleancoal.com.au/ECT/Coldry.html Coldry:Lignite Dewatering Process]


[[Category:Organic minerals]]

{{Sourceattribution|Lignite}}