Editing Potassium (section)

==Commercial production==
===Mining===
[[File:Museo de La Plata - Silvita.jpg|thumb|left| [[Sylvite]] from New Mexico]]
[[File:Wintershall Monte Kali 12.jpg|thumb|[[Monte Kali (Heringen)|Monte Kali]], a potash mining and [[beneficiation]] waste heap in [[Hesse|Hesse, Germany]], consisting mostly of [[sodium chloride]].]]

Potassium salts such as [[carnallite]], [[langbeinite]], [[polyhalite]], and [[sylvite]] form extensive [[evaporite]] deposits in ancient lake bottoms and [[seabed]]s,<ref name="geo" /> making extraction of potassium salts in these environments commercially viable. The principal source of potassium – potash – is mined in [[Canada]], [[Russia]], [[Belarus]], [[Kazakhstan]], [[Germany]], [[Israel]], the U.S., [[Jordan]], and other places around the world.<ref>{{cite book|url = https://books.google.com/books?id=EHx51n3T858C|publisher=Springer|title = Potash: deposits, processing, properties and uses|isbn = 978-0-412-99071-7|last1 = Garrett|first1= Donald E.|date = 1995-12-31}}</ref><ref name="USGSCS2008">{{cite web|url=http://minerals.usgs.gov/minerals/pubs/commodity/potash/mcs-2008-potas.pdf|first=Joyce A.|last=Ober|publisher=United States Geological Survey|title=Mineral Commodity Summaries 2008:Potash|access-date=2008-11-20|archive-date=2019-01-11|archive-url=https://web.archive.org/web/20190111170532/https://minerals.usgs.gov/minerals/pubs/commodity/potash/mcs-2008-potas.pdf|url-status=live}}</ref><ref name="USGSYB2006">{{cite web|url=https://minerals.usgs.gov/minerals/pubs/commodity/potash/myb1-2006-potas.pdf|first=Joyce A.|last=Ober|publisher=United States Geological Survey|title=Mineral Yearbook 2006:Potash|access-date=2008-11-20|archive-date=2008-12-17|archive-url=https://web.archive.org/web/20081217043522/http://minerals.usgs.gov/minerals/pubs/commodity/potash/myb1-2006-potas.pdf|url-status=live}}</ref> The first mined deposits were located near Staßfurt, Germany, but the deposits span from [[Great Britain]] over Germany into Poland. They are located in the [[Zechstein]] and were deposited in the Middle to Late [[Permian]]. The largest deposits ever found lie {{convert|1000|m|ft|abbr=off|sp=us}} below the surface of the Canadian province of [[Saskatchewan]]. The deposits are located in the [[Elk Point Group]] produced in the [[Middle Devonian]]. Saskatchewan, where several large mines have operated since the 1960s pioneered the technique of freezing of wet sands (the Blairmore formation) to drive mine shafts through them. The main potash mining company in Saskatchewan until its merge was the [[Potash Corporation of Saskatchewan]], now [[Nutrien]].<ref>{{cite book|url = https://books.google.com/books?id=rtRFyFO4hpEC&pg=PA433|publisher=U of Nebraska Press|page = 433|title = Encyclopedia of the Great Plains|isbn = 978-0-8032-4787-1|author1-link=David J. Wishart|last = Wishart| first=David J.|date = 2004}}</ref> The water of the [[Dead Sea]] is used by Israel and Jordan as a source of potash, while the concentration in normal oceans is too low for commercial production at current prices.<ref name="USGSCS2008" /><ref name="USGSYB2006" />

===Chemical extraction===
Several methods are used to separate potassium salts from sodium and magnesium compounds. The most-used method is fractional precipitation using the solubility differences of the salts. Electrostatic separation of the ground salt mixture is also used in some mines. The resulting sodium and magnesium waste is either stored underground or piled up in [[slag heap]]s. Most of the mined potassium mineral ends up as potassium chloride after processing. The mineral industry refers to potassium chloride either as potash, muriate of potash, or simply MOP.<ref name="indus" />

Pure potassium metal can be isolated by electrolysis of its [[potassium hydroxide|hydroxide]] in a process that has changed little since it was first used by Humphry Davy in 1807. Although the electrolysis process was developed and used in industrial scale in the 1920s, the thermal method by reacting sodium with [[potassium chloride]] in a chemical equilibrium reaction became the dominant method in the 1950s.
:Na + KCl → NaCl + K
The production of [[NaK|sodium potassium alloys]] is accomplished by changing the reaction time and the amount of sodium used in the reaction. The Griesheimer process employing the reaction of [[potassium fluoride]] with [[calcium carbide]] was also used to produce potassium.<ref name="indus" /><ref>{{cite book|doi=10.1002/0471238961.1615200103080921.a01.pub2|isbn= 978-0-471-23896-6
|last1=Chiu|first1=Kuen-Wai
|publisher=John Wiley & Sons, Inc.
|title=Kirk-Othmer Encyclopedia of Chemical Technology
|date=2000
|chapter= Potassium
}}</ref>

:{{chem2|2 KF + CaC2 → 2 K + CaF2 + 2 C}}

[[reagent|Reagent-grade]] potassium metal costs about $10.00/[[pound (mass)|pound]] ($22/[[kg]]) in 2010 when purchased by the [[tonne]]. Lower purity metal is considerably cheaper. The market is volatile because long-term storage of the metal is difficult. It must be stored in a dry [[inert gas]] atmosphere or [[anhydrous]] [[mineral oil]] to prevent the formation of a surface layer of [[potassium superoxide]], a pressure-sensitive [[explosive]] that [[Detonation|detonates]] when scratched. The resulting explosion often starts a fire difficult to extinguish.<ref>[[#Burkhardt|Burkhardt]], p. 34</ref><ref name="fire">{{cite journal|doi =10.1016/j.jchas.2006.09.010|title =Review of the safety of potassium and potassium oxides, including deactivation by introduction into water|year =2007|last1 =Delahunt|first1 = J.|last2 =Lindeman|first2 = T.|journal =Journal of Chemical Health and Safety|volume =14|issue =2|pages =21–32}}</ref><!--Kilogram quantities of potassium cost far more, in the range of $700/kg. This is partially due to the cost of [[hazardous material]] shipping requirements.-->

===Cation identification===
Potassium is now quantified by ionization techniques, but at one time it was quantitated by [[gravimetric analysis]].

Reagents used to precipitate potassium salts include [[sodium tetraphenylborate]], [[hexachloroplatinic acid]], and [[sodium cobaltinitrite]] into respectively [[potassium tetraphenylborate]], [[potassium hexachloroplatinate]], and [[potassium cobaltinitrite]].<ref name="HollemanAF" />
The reaction with [[sodium cobaltinitrite]] is illustrative:
:{{chem2|3 K+ + Na3[Co(NO2)6] → K3[Co(NO2)6] + 3 Na+}}
The potassium cobaltinitrite is obtained as a yellow solid.