Calcium carbide

<h2 id="production">Production</h2>
Calcium carbide is produced industrially in an <a href="/facts/Electric_arc_furnace/GgYK6Nz1">electric arc furnace</a> from a mixture of <a href="/facts/Lime_(mineral)/uMcVXGBM">lime</a> and <a href="/facts/Coke_(fuel)/vD8xjd0m">coke</a> at approximately 2,200 °C (3,990 °F).<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a> This is an <a href="/facts/Endothermic_reaction/06xmHw6Q">endothermic reaction</a> requiring 110 kilocalories (460 kJ) per mole<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a> and high temperatures to drive off the carbon monoxide. This method has not changed since its invention in 1892:

CaO + 3 C → CaC2 + CO
The high temperature required for this reaction is not practically achievable by traditional combustion, so the reaction is performed in an electric arc furnace with <a href="/facts/Graphite/sSf3KMXr">graphite</a> electrodes. The carbide product produced generally contains around 80% calcium carbide by weight. The carbide is crushed to produce small lumps that can range from a few mm up to 50 mm. The impurities are concentrated in the finer fractions. The CaC2 content of the product is assayed by measuring the amount of acetylene produced on <a href="/facts/Hydrolysis/JTvwIHPs">hydrolysis</a>. As an example, the British and German standards for the content of the coarser fractions are 295 L/kg and 300 L/kg respectively (at 101 kPa pressure and 20 °C (68 °F) temperature). Impurities present in the carbide include <a href="/facts/Calcium_phosphide/rCnNpWds">calcium phosphide</a>, which produces <a href="/facts/Phosphine/aYysn5TS">phosphine</a> when hydrolysed.<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a>
This reaction was an important part of the <a href="/facts/Industrial_Revolution/B6E3Fasm">Industrial Revolution</a> in chemistry, and was made possible in the United States as a result of massive amounts of inexpensive <a href="/facts/Hydroelectricity/zEeJIK2B">hydroelectric power</a> produced at <a href="/facts/Niagara_Falls/xoxUleQq">Niagara Falls</a> before the turn of the 20th century.<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a>
The electric arc furnace method was discovered in 1892 by <a href="/facts/Thomas_Willson/K1ha5lnQ">T. L. Willson</a>, and independently in the same year by <a href="/facts/Henri_Moissan/h4lE3nda">H. Moissan</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a><a class="footnote-ref" id="fnref:8" href="#fn:8">8</a><a class="footnote-ref" id="fnref:9" href="#fn:9">9</a> In <a href="/facts/Jajce/CqBKcTlP">Jajce</a>, <a href="/facts/Bosnia_and_Herzegovina/jNVA1gPB">Bosnia and Herzegovina</a>, the Austrian industrialist Josef Kranz and his "Bosnische-Elektrizitäts AG" company, whose successor later became "Elektro-Bosna", opened the largest chemical factory for the production of calcium carbide at the time in Europe in 1899. A <a href="/facts/Hydroelectric/zEeJIK2B">hydroelectric</a> power station on the <a href="/facts/Pliva_(river)/2auS55H0">Pliva</a> river with an installed capacity of 8 MW was constructed to supply electricity for the factory, the first power station of its kind in Southeast Europe, and became operational on 24 March 1899.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a>

<h2 id="crystal-structure">Crystal structure</h2>
Calcium carbide is a calcium <a href="/facts/Salt_(chemistry)/lsSKwGpn">salt</a> of <a href="/facts/Acetylene/yaDh6cmJ">acetylene</a>, consisting of <a href="/facts/Calcium/hf252CC0">calcium</a> <a href="/facts/Cations/wrbwhF3z">cations</a> Ca2+ and <a href="/facts/Acetylide/3u0EMxz3">acetylide</a> <a href="/facts/Anions/wrbwhF3z">anions</a> −C≡C−. Pure calcium carbide is a colourless solid. The common crystalline form at room temperature is a distorted <a href="/facts/Halite/9xEEKKT8">rock-salt structure</a> with the C2−2 units lying parallel.<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a> There are three different <a href="/facts/Polymorphism_(materials_science)/bu2tqsB9">polymorphs</a> which appear at room temperature: the tetragonal structure and two different monoclinic structures.<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a>

<h2 id="applications">Applications</h2>
<h3>Production of acetylene</h3>
The reaction of calcium carbide with water, producing acetylene and <a href="/facts/Calcium_hydroxide/Kz2KzRd8">calcium hydroxide</a>,<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a> was discovered by <a href="/facts/Friedrich_W%25C3%25B6hler/D7uh7ySD">Friedrich Wöhler</a> in 1862.

CaC2(<a href="/facts/Solid/hj5UsXno">s</a>) + 2 H2O(<a href="/facts/Liquid/t9GkLWzt">l</a>) → <a href="/facts/Acetylene/yaDh6cmJ">C2H2</a>(<a href="/facts/Gas/hVVAoodV">g</a>) + <a href="/facts/Calcium_hydroxide/Kz2KzRd8">Ca(OH)2</a>(<a href="/facts/Aqueous_solution/eRNr3MH2">aq</a>)
This reaction was the basis of the industrial manufacture of <a href="/facts/Acetylene/yaDh6cmJ">acetylene</a>, and is the major industrial use of calcium carbide.
Today acetylene is mainly manufactured by the partial combustion of methane or appears as a side product in the ethylene stream from cracking of hydrocarbons. Approximately 400,000 tonnes are produced this way annually (see <a href="/facts/Acetylene/yaDh6cmJ">acetylene preparation</a>).
In China, acetylene derived from calcium carbide remains a raw material for the <a href="/facts/Chemical_industry/3M6gfHer">chemical industry</a>, in particular for the production of <a href="/facts/Polyvinyl_chloride/9VkegJvr">polyvinyl chloride</a>. Locally produced acetylene is more economical than using imported oil.<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a> Production of calcium carbide in China has been increasing. In 2005 output was 8.94 million tons, with the capacity to produce 17 million tons.<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a>
In the United States, Europe, and Japan, consumption of calcium carbide is generally declining.<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a> Production levels in the US during the 1990s were 236,000 tons per year.<a class="footnote-ref" id="fnref:17" href="#fn:17">17</a>

<h3>Production of calcium cyanamide</h3>
Calcium carbide reacts with nitrogen at high temperature to form <a href="/facts/Calcium_cyanamide/IRcdYh9K">calcium cyanamide</a>:<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a>

CaC2 + N2 → CaCN2 + C
Commonly known as <a href="/facts/Nitrolime/IRcdYh9K">nitrolime</a>, calcium cyanamide is used as fertilizer. It is hydrolysed to <a href="/facts/Cyanamide/BNJKoGc0">cyanamide</a>, H2N−C≡N.<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a>

<h3>Steelmaking</h3>
Calcium carbide is used:

<ul><li>in the <a href="/facts/Desulfurization/YLIGdUcX">desulfurization</a> of iron (<a href="/facts/Pig_iron/bxLL2NaR">pig iron</a>, <a href="/facts/Cast_iron/lASt55k2">cast iron</a> and steel)<a class="footnote-ref" id="fnref:20" href="#fn:20">20</a></li>
<li>as a fuel in steelmaking to extend the scrap ratio to liquid iron, depending on economics.</li>
<li>as a powerful <a href="/facts/Deoxidizer/dvIowzuC">deoxidizer</a> at <a href="/facts/Ladle_(metallurgy)/UaRLtxyv">ladle</a> treatment facilities.</li></ul>
<h3>Carbide lamps</h3>
Main article: <a href="/facts/Carbide_lamp/YQkr2aGe">Carbide lamp</a>
Calcium carbide is used in <a href="/facts/Carbide_lamp/YQkr2aGe">carbide lamps</a>. Water dripping on carbide produces acetylene gas, which burns and produces light. While these lamps gave steadier and brighter light than candles, they were dangerous in <a href="/facts/Coal/83kV3qxg">coal</a> mines, where flammable <a href="/facts/Methane/kBHneYnh">methane</a> gas made them a serious hazard. The presence of flammable gases in coal mines led to miner <a href="/facts/Safety_lamp/yctjsSbe">safety lamps</a> such as the <a href="/facts/Davy_lamp/PfePf9j6">Davy lamp</a>, in which a wire gauze reduces the risk of methane ignition. Carbide lamps were still used extensively in <a href="/facts/Slate/hSVHL6Lj">slate</a>, <a href="/facts/Copper/I8PEE8oX">copper</a>, and <a href="/facts/Tin/obW9mqc3">tin</a> mines where methane is not a serious hazard. Most miners' lamps have now been replaced by electric <a href="/facts/Headlamp_(outdoor)/TCCNRdl2">lamps</a>.
Carbide lamps are still used for mining in some less wealthy countries, for example in the <a href="/facts/Silver/xXe41BGg">silver</a> mines near <a href="/facts/Potos%25C3%25AD/cGSUkAHT">Potosí</a>, <a href="/facts/Bolivia/YNBoDKKR">Bolivia</a>. Carbide lamps are also still used by some <a href="/facts/Caving/j1nPy3bw">cavers</a> exploring caves and other underground areas,<a class="footnote-ref" id="fnref:21" href="#fn:21">21</a> although they are increasingly being replaced in this use by <a href="/facts/Light-emitting_diode/gE8x4MDb">LED</a> lights.
Carbide lamps were also used extensively as <a href="/facts/Headlamp/7fg0kjKa">headlamps</a> in early automobiles, motorcycles and bicycles, but have been replaced entirely by electric lamps.<a class="footnote-ref" id="fnref:22" href="#fn:22">22</a>

<h3>Other uses</h3>
Calcium carbide is sometimes used as source of acetylene, which like <a href="/facts/Ethylene/QMNBYLYn">ethylene</a> gas, is a <a href="/facts/Ripening_agent/Nkn4Mqdh">ripening agent</a>.<a class="footnote-ref" id="fnref:23" href="#fn:23">23</a> However, this is illegal in some countries as, in the production of acetylene from calcium carbide, contamination often leads to trace production of <a href="/facts/Phosphine/aYysn5TS">phosphine</a> and <a href="/facts/Arsine/VkH6217V">arsine</a>.<a class="footnote-ref" id="fnref:24" href="#fn:24">24</a><a class="footnote-ref" id="fnref:25" href="#fn:25">25</a> These impurities can be removed by passing the acetylene gas through acidified <a href="/facts/Copper(II)_sulfate/Ya6fPoQe">copper sulfate</a> solution, but, in developing countries, this precaution is often neglected.
Calcium carbide is used in toy cannons such as the <a href="/facts/Big-Bang_Cannon/sd1Mva5R">Big-Bang Cannon</a>, as well as in <a href="/facts/Bamboo_cannon/0VF42LWs">bamboo cannons</a>. In the Netherlands calcium carbide is used around new-year to shoot with milk churns.<a class="footnote-ref" id="fnref:26" href="#fn:26">26</a>
Calcium carbide, together with <a href="/facts/Calcium_phosphide/rCnNpWds">calcium phosphide</a>, is used in floating, self-igniting naval <a href="/facts/Flare/LuXg6UXI">signal flares</a>, such as those produced by the <a href="/facts/Holmes%2527_Marine_Life_Protection_Association/dE3R2VTu">Holmes' Marine Life Protection Association</a>.
Calcium carbide is used to determine the moisture content of soil. When soil and calcium carbide are mixed in a closed pressure cylinder, the water content in soil reacts with calcium carbide to release acetylene whose pressure can be measured to determine the moisture content.<a class="footnote-ref" id="fnref:27" href="#fn:27">27</a><a class="footnote-ref" id="fnref:28" href="#fn:28">28</a>
Calcium carbide is sold commercially as a <a href="/facts/Mole_(animal)/tunKPGPu">mole</a> repellent.<a class="footnote-ref" id="fnref:29" href="#fn:29">29</a> When it comes into contact with water, the gas produced drives moles away.<a class="footnote-ref" id="fnref:30" href="#fn:30">30</a>

<h2 id="external-links">External links</h2>
<ul><li><a href="http://www.periodicvideos.com/videos/mv_calcium_carbide.htm">Calcium Carbide & Acetylene</a> at <a href="/facts/The_Periodic_Table_of_Videos/vC5kbN0M">The Periodic Table of Videos</a> (University of Nottingham)</li>
<li><a href="http://www.epa.gov/ttn/chief/ap42/ch11/final/c11s04.pdf">Calcium Carbide Manufacturing</a></li>
<li><a href="https://web.archive.org/web/20121119023814/http://www.scholarchemistry.com/msds/Cal_Carbide.pdf">2008 Material Safety Data Sheet</a></li></ul>

<h2 id="references">References</h2>

<ol>
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<li id="fn:2">Vincoli, Jeffrey Wayne (25 November 1996). Risk Management for Hazardous Chemicals. CRC Press. p. 429. ISBN 978-1-56670-200-3. <a href="978-1-56670-200-3" target="_blank">978-1-56670-200-3</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 298. ISBN 978-0-08-037941-8. <a href="978-0-08-037941-8" target="_blank">978-0-08-037941-8</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Calculated from data in the CRC Handbook of Chemistry and Physics. <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Holzrichter, Klaus; Knott, Alfons; Mertschenk, Bernd; Salzinger, Josef (2013). "Calcium Carbide". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–14. doi:10.1002/14356007.a04_533.pub2. ISBN 978-3-527-30673-2. <a href="978-3-527-30673-2" target="_blank">978-3-527-30673-2</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Freeman, Horace (1919). "Manufacture of Cyanamide". The Chemical News and the Journal of Physical Science. 117: 232. <a href="https://books.google.com/books?id=5SAzAQAAMAAJ&pg=PA232" target="_blank">https://books.google.com/books?id=5SAzAQAAMAAJ&pg=PA232</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Morehead, J. T. and de Chalmot, G. (1896). "The Manufacture of Calcium Carbide". Journal of the American Chemical Society. 18 (4): 311–331. Bibcode:1896JAChS..18..311M. doi:10.1021/ja02090a001.{{cite journal}}: CS1 maint: multiple names: authors list (link) <a href="https://zenodo.org/record/1428938" target="_blank">https://zenodo.org/record/1428938</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
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<li id="fn:9">Renouf, Edward (1899). "The use of Acetylene". Popular Science Monthly: 335–347. <a href="https://books.google.com/books?id=wyIDAAAAMBAJ&pg=PA336" target="_blank">https://books.google.com/books?id=wyIDAAAAMBAJ&pg=PA336</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
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<li id="fn:12">Konar, Sumit; Nylén, Johanna; Svensson, Gunnar; Bernin, Diana; Edén, Mattias; Ruschewitz, Uwe; Häussermann, Ulrich (2016). "The many phases of CaC2". Journal of Solid State Chemistry. 239. Elsevier BV: 204–213. Bibcode:2016JSSCh.239..204K. doi:10.1016/j.jssc.2016.04.030. ISSN 0022-4596. <a href="https://doi.org/10.1016%2Fj.jssc.2016.04.030" target="_blank">https://doi.org/10.1016%2Fj.jssc.2016.04.030</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 298. ISBN 978-0-08-037941-8. <a href="978-0-08-037941-8" target="_blank">978-0-08-037941-8</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
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<li id="fn:15">"Government takes measures to curb development of calcium carbide sector". China Daily via BusyTrade.com. 2007-05-16. Archived from the original on 2007-02-11.{{cite news}}: CS1 maint: bot: original URL status unknown (link) <a href="https://web.archive.org/web/20070211125931/http://www.busytrade.com/news/newsinfo.php?id=2425" target="_blank">https://web.archive.org/web/20070211125931/http://www.busytrade.com/news/newsinfo.php?id=2425</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">Lacson, Jamie; Schlag, Stefan; Toki, Goro (December 2004). "Calcium Carbide". SRI Consulting. <a href="http://www.sriconsulting.com/CEH/Public/Reports/724.5000/" target="_blank">http://www.sriconsulting.com/CEH/Public/Reports/724.5000/</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8. <a href="978-0-08-037941-8" target="_blank">978-0-08-037941-8</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 298. ISBN 978-0-08-037941-8. <a href="978-0-08-037941-8" target="_blank">978-0-08-037941-8</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 298. ISBN 978-0-08-037941-8. <a href="978-0-08-037941-8" target="_blank">978-0-08-037941-8</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">Holzrichter, Klaus; Knott, Alfons; Mertschenk, Bernd; Salzinger, Josef (2013). "Calcium Carbide". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–14. doi:10.1002/14356007.a04_533.pub2. ISBN 978-3-527-30673-2. <a href="978-3-527-30673-2" target="_blank">978-3-527-30673-2</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
<li id="fn:21">"Caving equipment and culture (from Te Ara Encyclopedia of New Zealand)". <a href="https://www.teara.govt.nz/TheBush/BushAndMountainRecreation/Caving/4/en" target="_blank">https://www.teara.govt.nz/TheBush/BushAndMountainRecreation/Caving/4/en</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></li>
<li id="fn:22">Clemmer, Gregg (1987). American Miners' Carbide Lamps: A Collectors Guide to American Carbide Mine Lighting. Westernlore Publications. <a href="#fnref:22" class="footnote-back-ref">↩</a></li>
<li id="fn:23">Abeles, F. B. and Gahagan, H. E. III (1968). "Abscission: The Role of Ethylene, Ethylene Analogues, Carbon Dioxide, and Oxygen". Plant Physiol. 43 (8): 1255–1258. doi:10.1104/pp.43.8.1255. PMC 1087003. PMID 16656908.{{cite journal}}: CS1 maint: multiple names: authors list (link) <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1087003" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1087003</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></li>
<li id="fn:24">"Bet on it. Your mango is ripened using carbide". dna. 2013-05-18. Retrieved 2018-08-25. <a href="http://www.dnaindia.com/ahmedabad/1836343/report-bet-on-it-your-mango-is-ripened-using-carbide" target="_blank">http://www.dnaindia.com/ahmedabad/1836343/report-bet-on-it-your-mango-is-ripened-using-carbide</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></li>
<li id="fn:25">"Eating Artificially Ripened Fruits is Harmful". <a href="https://www.researchgate.net/publication/229429873" target="_blank">https://www.researchgate.net/publication/229429873</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></li>
<li id="fn:26">"Carbidschieten wordt feest" (in Dutch). Algemeen Dagblad. 2016-12-24. <a href="https://www.ad.nl/dossier-rotterdam/carbidschieten-wordt-feest~af671013/" target="_blank">https://www.ad.nl/dossier-rotterdam/carbidschieten-wordt-feest~af671013/</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></li>
<li id="fn:27">Singh, Randhir (17 December 2008). "Determining Water Content In Soil – Calcium Carbide Method". Civil Engineering Portal. Retrieved 7 September 2020. <a href="https://www.engineeringcivil.com/determining-water-content-in-soil-calcium-carbide-method.html" target="_blank">https://www.engineeringcivil.com/determining-water-content-in-soil-calcium-carbide-method.html</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></li>
<li id="fn:28">ASTM International. "ASTM D4944-18, Standard Test Method for Field Determination of Water (Moisture) Content of Soil by the Calcium Carbide Gas Pressure Tester". ASTM International. Retrieved 7 September 2020. <a href="https://www.astm.org/Standards/D4944.htm" target="_blank">https://www.astm.org/Standards/D4944.htm</a> <a href="#fnref:28" class="footnote-back-ref">↩</a></li>
<li id="fn:29">du Bois, T.M.E. (20 February 2014). "Molehill Mayhem". p. 21. hdl:1874/290102. Archived from the original on 25 March 2022. Retrieved 15 January 2021. <a href="https://web.archive.org/web/20220325113038/https://dspace.library.uu.nl/handle/1874/290102" target="_blank">https://web.archive.org/web/20220325113038/https://dspace.library.uu.nl/handle/1874/290102</a> <a href="#fnref:29" class="footnote-back-ref">↩</a></li>
<li id="fn:30">"How to Get Rid of Yard Moles With Carbide". mysunnylawn.com. <a href="http://www.mysunnylawn.com/a90851.php" target="_blank">http://www.mysunnylawn.com/a90851.php</a> <a href="#fnref:30" class="footnote-back-ref">↩</a></li>
</ol>

Calcium carbide open-in-new

Calcium carbide