Potash /ˈpɒtæʃ/ is the common name for various mined and manufactured salts that contain potassium in water-soluble form.[1] In some rare cases, potash can be formed with traces of organic materials such as plant remains, and this was the major historical source for it before the industrial era. The name derives from "pot ash," which refers to plant ashes soaked in water in a pot.

Today, potash is produced worldwide at amounts exceeding 30 million tonnes per year, mostly for use in fertilizers. Various types of fertilizer-potash thus comprise the single largest global industrial use of the element potassium. Potassium derives its name from potash, from which it was first derived by electrolysis of caustic potash, in 1808.



Potash refers to potassium compounds and potassium-bearing materials, the most common being potassium chloride (KCl). The term "potash" comes from the Old Dutch word potaschen. The old method of making potassium carbonate (K2CO3) was by leaching of wood ashes and then evaporating the resulting solution in large iron pots, leaving a white residue called "pot ash". Approximately 10% by weight of common wood ash can be recovered as pot ash.[2][3] Later, "potash" became the term widely applied to naturally occurring potassium salts and the commercial product derived from them.[4]

The following table lists a number of potassium compounds which use the word potash in their traditional names:

Common name Chemical name Formula
Potash fertilizer c.1942 potassium carbonate; c.1950 any one or more of potassium chloride, potassium sulfate (K2SO4), potassium magnesium sulfate (K2SO4·2MgSO4), langbeinite (K2Mg2(SO4)3) or potassium nitrate.[5][6] Does not contain potassium oxide, which plants do not take up.[7]
Caustic potash or potash lye potassium hydroxide KOH
Carbonate of potash, salts of tartar, or pearlash   potassium carbonate K2CO3
Chlorate of potash potassium chlorate KClO3
Muriate of potash potassium chloride KCl:NaCl (95:5 or higher)[1]
Nitrate of potash or saltpeter potassium nitrate KNO3
Sulfate of potash potassium sulfate K2SO4
Permanganate of potash potassium permanganate KMnO4

History of production

Potash (especially potassium carbonate) has been used from the dawn of history in bleaching textiles, making glass, and, from about A.D. 500, in making soap. Potash was principally obtained by leaching the ashes of land and sea plants. Beginning in the 14th century potash was mined in Ethiopia. One of the world's largest deposits, 140 to 150 million tons, is located in the Tigray's Dallol area.[8] Potash was one of the most important industrial chemicals in Canada. It was refined from the ashes of broadleaved trees and produced primarily in the forested areas of Europe, Russia, and North America. The first U.S. patent was issued in 1790 to Samuel Hopkins for an improvement "in the making Pot ash and Pearl ash by a new Apparatus and Process."[9]

As early as 1767, potash from wood ashes was exported from Canada, and exports of potash and pearl ash (potash and lime) reached 43,958 barrels in 1865. There were 519 asheries in operation in 1871. The industry declined in the late 19th century when large-scale production of potash from mineral salts was established in Germany. In 1943, potash was discovered in Saskatchewan, Canada, in the process of drilling for oil. Active exploration began in 1951. In 1958, the Potash Company of America became the first potash producer in Canada with the commissioning of an underground potash mine at Patience Lake; however, due to water seepage in its shaft, production stopped late in 1959 and, following extensive grouting and repairs, resumed in 1965. The underground mine was flooded in 1987 and was reactivated for commercial production as a solution mine in 1989.[3]

In the late 18th and early 19th centuries, potash production provided settlers in North America a way to obtain badly-needed cash and credit as they cleared wooded land for crops. To make full use of their land, settlers needed to dispose of excess wood. The easiest way to accomplish this was to burn any wood not needed for fuel or construction. Ashes from hardwood trees could then be used to make lye, which could either be used to make soap or boiled down to produce valuable potash. Hardwood could generate ashes at the rate of 60 to 100 bushels per acre (500 to 900 m3/km2). In 1790, ashes could be sold for $3.25 to $6.25 per acre ($800 to $1500/km2) in rural New York State – nearly the same rate as hiring a laborer to clear the same area. Potash making became a major industry in British North America. Great Britain was always the most important market. The American potash industry followed the woodsman's ax across the country. After about 1820, New York replaced New England as the most important source; by 1840 the center was in Ohio. Potash production was always a by-product industry, following from the need to clear land for agriculture.[10]

Most of the world reserves of potassium (K) were deposited as sea water in ancient inland oceans evaporated, and the potassium salts crystallized into beds of potash ore. These are the locations where potash is currently being mined today. The deposits are a naturally-occurring mixture of potassium chloride (KCl) and sodium chloride (NaCl), better known as common table salt. Over time, as the surface of the earth changed, these deposits were covered by thousands of feet of earth.[10]

Most potash mines today are deep shaft mines as much as 4,400 feet (1,400 m) underground. Others are mined as strip mines, having been laid down in horizontal layers as sedimentary rock. In above-ground processing plants, the KCl is separated from the mixture to produce a high analysis natural potassium fertilizer. Other naturally occurring potassium salts can be separated by various procedures, resulting in potassium sulfate and potassium-magnesium sulfate.

Today some of the world's largest known potash deposits are spread all over the world from Saskatchewan, Canada, to Brazil, Belarus, Germany, and more notably the Permian Basin. The Permian basin deposit includes the major mines outside of Carlsbad, New Mexico, to the world's purest potash deposit in Lea County New Mexico (not far from the Carlsbad deposits), which is believed to be roughly 80% pure. Canada is the largest producer, followed by Russia and Belorussia. The most significant reserve of Canada's potash is located in the province of Saskatchewan and controlled by the Potash Corporation of Saskatchewan.[1]

In the beginning of the 20th century, potash deposits were found in the Dallol Depression in Musely and Crescent localities near the Ethiopean-Eritrean border. The estimated reserves are 173 and 12 million tonnes for the Musely and Crescent, respectively. The latter is particularly suitable for surface mining; it was explored in the 1960s but the works stopped due to the flood in 1967. Attempts to continue mining in the 1990s were halted by the Eritrean–Ethiopian War and have not resumed by 2009.[11]


Production and resources of potash
(2010, in million tonnes)[12]
Country Production Reserves
 Canada 9.5 4400
 Russia 6.8 3300
 Belarus 5.0 750
 China 3.0 210
 Germany 3.0 150
 Israel 2.1 40
 Jordan 1.2 40
 United States 0.9 130
 Chile 0.7 70
 Brazil 0.4 300
 United Kingdom 0.4 22
 Spain 0.4 20
Other countries 50
World total 33 9500


Potash output in 2005

Potassium is the seventh most abundant element in the Earth's crust, and is the third major plant and crop nutrient after nitrogen and phosphorus. It has been used since antiquity as a soil fertilizer (about 90% of current use).[2] Potash is important for agriculture because it improves water retention, yield, nutrient value, taste, colour, texture and disease resistance of food crops. It has wide application to fruit and vegetables, rice, wheat and other grains, sugar, corn, soybeans, palm oil and cotton, all of which benefit from the nutrient’s quality enhancing properties.[13]

Demand for food and animal feed has been on the rise since 2000. The U.S. Department of Agriculture’s Economic Research Service (ERS) attributes the trend to average annual population increases of 75 million people around the world. Geographically, economic growth in Asia and Latin America greatly contributed to the increased use of potash-based fertilizer. Rising incomes in developing countries also was a factor in the growing potash and fertilizer use. With more money in the household budget, consumers added more meat and dairy products to their diets. This shift in eating patterns required more acres to be planted, more fertilizer to be applied and more animals to be fed – all requiring more potash.

After years of trending upward, fertilizer use slowed in 2008. The worldwide economic downturn is the primary reason for the declining fertilizer use, dropping prices and mounting inventories.[14][15]

The world's largest consumers of potash are China, the United States, Brazil and India.[16] Brazil imports 90% of the potash it needs.[16][9]

Potash imports and exports are often reported in "K2O equivalent", although fertilizer never contains potassium oxide, per se, because potassium oxide is caustic and hygroscopic.

Potash prices have soared in recent years. What was once a commodity worth about $200 a tonne is expected to reach $1,500 by 2020; Vancouver prices are US$872.50 per tonne in 2009, which is a record high.[17] As of November 2011 potash prices have dropped to about $470 per metric tonne.[18]

Other uses

In addition to its use as a fertilizer, potassium chloride is important in industrialized economies, where it is used in aluminium recycling, by the chloralkali industry to produce potassium hydroxide, in metal electroplating, oil-well drilling fluid, snow and ice melting, steel heat-treating, and water softening. Potassium hydroxide is used for industrial water treatment and is the precursor of potassium carbonate, several forms of potassium phosphate, many other potassic chemicals, and soap manufacturing. Potassium carbonate is used to produce animal feed supplements, cement, fire extinguishers, food products, photographic chemicals, and textiles. It is also used in brewing beer, pharmaceutical preparations, and as a catalyst for synthetic rubber manufacturing. These nonfertilizer uses have accounted for about 15% of annual potash consumption in the United States.[1]

Potash (potassium carbonate) along with hartshorn was also used as a baking aid similar to baking soda in old German baked goods such as lebkuchen (ginger bread).[19]


 This article incorporates public domain material from the United States Geological Survey document "Potash".

  1. ^ a b c d Potash, USGS 2008 Minerals Yearbook
  2. ^ a b Stephen M. Jasinski. "Potash". USGS. http://minerals.usgs.gov/minerals/pubs/commodity/potash/. 
  3. ^ a b "Potash". The Canadian Encyclopedia. http://www.thecanadianencyclopedia.com/index.cfm?PgNm=TCE&Params=A1ARTA0006428. 
  4. ^ "The World Potash Industry: Past, Present and Future". New Orleans, LA: 50th Anniversary Meeting The Fertilizer Industry Round Table. 2000. http://www.potashcorp.com/media/pdf/investor_relations/speeches/world_potash_industry.pdf. 
  5. ^ Dennis Kostick (September 2006). "Potash" (PDF). 2005 Minerals Handbook. United States Geological Survey. p. 58.1. http://minerals.usgs.gov/minerals/pubs/commodity/potash/potasmyb05.pdf. Retrieved 2011-01-29. 
  6. ^ J. W. Turrentine (1934). "Composition of Potash Fertilizer Salts for Sale on the American Market". Industrial & Engineering Chemistry (American Chemical Society) 26 (11): 1224–1225. 
  7. ^ Joseph R. Heckman (January 17, 2002). Plant & Pest Advisory. 7. Rutgers University. p. 3. http://njaes.rutgers.edu/pubs/plantandpestadvisory/2002/fc0117.pdf. 
  8. ^ Ethiopia Mining
  9. ^ a b Kids – Time Machine – Historic Press Releases – USPTO
  10. ^ a b Fite, Robert C Origin and occurrence of commercial potash deposits, Academy of Sciences for 1951
  11. ^ "Minerals for Agricultural Industrialization". Ministry of Mines and Energy of Ethiopia. http://www.mome.gov.et/industrial.html. 
  12. ^ Stephen M. Jasinski Potash, USGS Mineral Commodity Summary 2011
  13. ^ Potash Price Close to all time highs – Future Outlook
  14. ^ Potash Around the World
  15. ^ "Potash global review: tunnel vision", Industrial Minerals, May 2009
  16. ^ a b Supply and Demand
  17. ^ "Potash prices are record high". Potash Investing news. February 5, 2009. http://www.potashinvestingnews.com/354-potash-prices-at-record-high.html. 
  18. ^ http://www.infomine.com/chartsanddata/chartbuilder.aspx?z=f&g=127651&dr=2y
  19. ^ Cameron French (June 14, 2008). "Potash: The new gold rush". Globe and Mail. http://www.reportonbusiness.com/servlet/story/RTGAM.20080613.wpotash0613/BNStory/energy/home?cid=al_gam_mostemail. Retrieved 2008-06-01. 

Further reading

External links

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Look at other dictionaries:

  • Potash — Potash, from the Dutch potaschen, meaning pot ashes, is the common name for any of several compounds containing potassium, such as potassium carbonate (K2CO3), potassium oxide (K2O) and potassium chloride (KCl). These compounds are used primarily …   Investment dictionary

  • Potash — Pot ash , n. [Pot + ash.] (Chem.) (a) The hydroxide of potassium hydrate, a hard white brittle substance, {KOH}, having strong caustic and alkaline properties; hence called also {caustic potash}. (b) The impure potassium carbonate obtained by… …   The Collaborative International Dictionary of English

  • potash — 1640s, loan translation of Du. potaschen, lit. pot ashes; so called because it was originally obtained by soaking wood ashes in water and evaporating the mixture in an iron pot. Cf. Ger. Pottasche, Dan. potaske, Swed. pottaska. See also POTASSIUM …   Etymology dictionary

  • potash — ► NOUN ▪ an alkaline potassium compound, especially potassium carbonate or hydroxide. ORIGIN from pot ashes, because originally obtained by leaching vegetable ashes and evaporating the solution in iron pots …   English terms dictionary

  • potash — [pät′ash΄] n. [earlier in pl., potashes < Du potasschen < pot, POT1 + asch, ASH1: orig. prepared by evaporating the lixivium of wood ashes in iron pots] 1. a) POTASSIUM CARBONATE (esp. when obtained from wood ashes) …   English World dictionary

  • potash — /pot ash /, n. 1. potassium carbonate, esp. the crude impure form obtained from wood ashes. 2. potassium hydroxide. 3. the oxide of potassium, K2O. 4. potassium, as carbonate of potash. [1615 25; back formation from pl. pot ashes, trans. of early …   Universalium

  • potash — /ˈpɒtæʃ / (say potash) noun 1. potassium carbonate, especially the crude impure form obtained from wood ashes. 2. → caustic potash. 3. the oxide of potassium, K2O. 4. potassium: carbonate of potash. {earlier pot ashes, plural, translation of… …   Australian English dictionary

  • potash — [17] Potassium carbonate was originally obtained by burning wood or other vegetable matter, soaking the ashes in water, and evaporating the resulting liquid in iron pots. The potato 390 resulting substance was hence called in early modern Dutch… …   The Hutchinson dictionary of word origins

  • potash — [17] Potassium carbonate was originally obtained by burning wood or other vegetable matter, soaking the ashes in water, and evaporating the resulting liquid in iron pots. The resulting substance was hence called in early modern Dutch potasschen,… …   Word origins

  • potash — [[t]pɒ̱tæʃ[/t]] N UNCOUNT Potash is a white powder obtained from the ashes of burnt wood and is sometimes used as a fertilizer …   English dictionary