Potash
   HOME

TheInfoList



OR:

Potash ( ) includes various mined and manufactured salts that contain
potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
in water- soluble form.Potash
, USGS 2008 Minerals Yearbook
The name derives from ''pot ash'', plant ashes or
wood ash Wood ash is the powder (substance), powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds, along with other non-combustible ...
soaked in water in a pot, the primary means of manufacturing potash before the Industrial Era. The word ''
potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
'' is derived from ''potash''. Potash is produced worldwide in amounts exceeding 71.9 million
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...
s (~45.4 million tonnes K2O equivalent) per year as of 2021, with Canada being the largest producer, mostly for use in fertilizer. Various kinds of fertilizer-potash constitute the single greatest industrial use of the element potassium in the world. Potassium was first derived in 1807 by
electrolysis In chemistry and manufacturing, electrolysis is a technique that uses Direct current, direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of c ...
of caustic potash (
potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...
).


Terminology

Potash refers to potassium compounds and potassium-bearing materials, most commonly potassium carbonate. The word "potash" originates from the Middle Dutch , denoting "pot ashes" in 1477. The old method of making potassium carbonate () was by collecting or producing
wood ash Wood ash is the powder (substance), powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds, along with other non-combustible ...
(the occupation of ash burners), leaching the ashes, and then evaporating the resulting solution in large iron pots, which left a white residue denominated "pot ash". Approximately 10% by weight of common
wood ash Wood ash is the powder (substance), powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds, along with other non-combustible ...
can be recovered as potash. Later, "potash" became widely applied to naturally occurring minerals that contained potassium salts and the commercial product derived from them. The following table lists a number of potassium compounds that have "potash" in their traditional names:


History


Origin of potash ore

Most of the world reserves of potassium (K) were deposited as sea water in ancient inland oceans. After the water evaporated, the potassium salts crystallized into beds of potash ore. These are the locations where potash is being mined today. The deposits are a naturally occurring mixture of potassium chloride (KCl; mineral name sylvite) and sodium chloride (NaCl; mineral name halite), more commonly known as table salt. Over time, as the surface of the earth changed, these deposits were covered by thousands of feet of earth.Robert C. Fit
Origin and occurrence of commercial potash deposits
, ''Academy of Sciences for 1951'', p. 123


Bronze Age

Potash (especially potassium carbonate) has been used in bleaching textiles, making
glass Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...
, ceramic, and making
soap Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...
, since the
Bronze Age The Bronze Age () was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of ...
. Potash was principally obtained by leaching the ashes of wood burned for heating and cooking.


14th–17th century


Potash mining

Beginning in the 14th century potash was mined in
Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Ken ...
. One of the world's largest deposits, 140 to 150 million tons, is located in the Dallol area of the
Afar Region The Afar Region (; ; ), formerly known as Region 2, is a Regions of Ethiopia, regional state in northeastern Ethiopia and the homeland of the Afar people. Its capital is the planned city of Semera, which lies on the paved Awash, Ethiopia, Awash� ...
.Ethiopia Mining
Photius.com. Retrieved on 2013-06-21.


Wood-derived potash

Potash was one of the most important industrial chemicals. It was refined from the ashes of broadleaved trees and produced primarily in the forested areas of Europe,
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
, and
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
. Although methods for producing artificial alkalis were invented in the late 18th century, these did not become economical until the late 19th century and so the dependence on organic sources of potash remained. Potash became an important international trade commodity in Europe from at least the early 14th century. It is estimated that European imports of potash required 6 or more million cubic metres each year from the early 17th century. Between 1420 and 1620, the primary exporting cities for wood-derived potash were
Gdańsk Gdańsk is a city on the Baltic Sea, Baltic coast of northern Poland, and the capital of the Pomeranian Voivodeship. With a population of 486,492, Data for territorial unit 2261000. it is Poland's sixth-largest city and principal seaport. Gdań ...
,
Königsberg Königsberg (; ; ; ; ; ; , ) is the historic Germany, German and Prussian name of the city now called Kaliningrad, Russia. The city was founded in 1255 on the site of the small Old Prussians, Old Prussian settlement ''Twangste'' by the Teuton ...
and
Riga Riga ( ) is the capital, Primate city, primate, and List of cities and towns in Latvia, largest city of Latvia. Home to 591,882 inhabitants (as of 2025), the city accounts for a third of Latvia's total population. The population of Riga Planni ...
. In the late 15th century, London was the lead importer due to its position as the centre of soft soap making while the Dutch dominated as suppliers and consumers in the 16th century.Paul Warde, 'Trees, Trade and Textiles: Potash Imports and Ecological Dependency in British Industry, c. 1550–1770', Past & Present, 240, 1, 2018, 47–82 From the 1640s, geopolitical disruptions (i.e.
Russo-Polish War (1654–1667) Armed conflicts between Poland (including the Polish–Lithuanian Commonwealth and the Crown of the Kingdom of Poland) and Russia (including the Soviet Union, the Russian Empire, the Tsardom of Russia and the Principality of Moscow) include: : : ...
) meant that the centres of export moved from the Baltic to Archangelsk, Russia. In 1700, Russian ash was dominant though Gdańsk remained notable for the quality of its potash.


18th century


Kelp ash

On the
Orkney Orkney (), also known as the Orkney Islands, is an archipelago off the north coast of mainland Scotland. The plural name the Orkneys is also sometimes used, but locals now consider it outdated. Part of the Northern Isles along with Shetland, ...
islands, kelp ash provided potash and soda ash, production starting "possibly as early as 1719" and lasting for a century. The products were "eagerly sought after by the glass and soap industries of the time."


North America

By the 18th century, higher quality American potash was increasingly exported to Britain. In the late 18th and early 19th centuries, potash production provided settlers in North America 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 Hardwood is wood from Flowering plant, angiosperm trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal ecosystem, boreal latitudes they are mostly deciduous, but in tropics and subtropics mostl ...
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, the sale of ashes could generate $3.25 to $6.25 per acre ($800 to $1,500/km2) in rural
New York State New York, also called New York State, is a state in the northeastern United States. Bordered by New England to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and ...
– 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.


The first US patent

The first US patent of any kind was issued in 1790 to Samuel Hopkins for an improvement "in the making of Pot ash and Pearl ash by a new Apparatus and Process". ''Pearl ash'' was a purer quality made by
calcination Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally f ...
of potash in a reverberatory furnace or kiln. Potash pits were once used in
England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...
to produce potash that was used in making soap for the preparation of wool for yarn production.


19th century

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 Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
.


Canada

From 1767, potash from wood ashes was exported from Canada. By 1811, 70% of the total 19.6 million lbs of potash imports to Britain came from Canada. Exports of potash and pearl ash reached 43,958 barrels in 1865. There were 519 asheries in operation in 1871.


20th century industrialization

The wood-ash industry declined in the late 19th century when large-scale production of potash from mineral salts was established in
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
. In the early 20th century, the potash industry was dominated by a cartel in which Germany had the dominant role. WWI saw a brief resurgence of American asheries, with their product typically consisting of 66% hydroxide, 17% carbonate, 16% sulfate and other impurities. Later in the century, the cartel ended as new potash producers emerged in the USSR and Canada. In 1943, potash was discovered in
Saskatchewan Saskatchewan is a Provinces and territories of Canada, province in Western Canada. It is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by the ...
, Canada, during oil drilling. 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. As numerous potash producers in Canada developed, the Saskatchewan government became increasingly involved in the industry, leading to the creation of Canpotex in the 1970s. In 1964 the Canadian company Kalium Chemicals established the first potash mine using the solution process. The discovery was made during oil reserve exploration. The mine was developed near Regina, Saskatchewan. The mine reached depths greater than 1500 meters. It is now the Mosaic Corporation's Belle Plaine unit. The USSR's potash production had largely been for domestic use and use in the Council for Mutual Economic Assistance countries. After the
dissolution of the USSR Dissolution may refer to: Arts and entertainment * ''Dissolution'', a 2002 novel by Richard Lee Byers in the War of the Spider Queen series * Dissolution (Sansom novel), ''Dissolution'' (Sansom novel), by C. J. Sansom, 2003 * Dissolution (Binge no ...
, Russian and Belarusian potash producers entered into direct competition with producers elsewhere in the world for the first time. In the beginning of the 20th century, potash deposits were found in the Dallol Depression in the Musely and Crescent localities near the Ethiopean-
Eritrea Eritrea, officially the State of Eritrea, is a country in the Horn of Africa region of East Africa, with its capital and largest city being Asmara. It is bordered by Ethiopia in the Eritrea–Ethiopia border, south, Sudan in the west, and Dj ...
n border. The estimated reserves in Musely and Crescent are 173 and 12 million tonnes respectively. The latter is particularly suitable for surface mining. It was explored in the 1960s but the works stopped due to flooding in 1967. Attempts to continue mining in the 1990s were halted by the Eritrean–Ethiopian War and have not resumed as of 2009.


Mining


Shaft mining and strip mining

All commercial potash deposits come originally from evaporite deposits and are often buried deep below the earth's surface. Potash ores are typically rich in potassium chloride (KCl), sodium chloride (NaCl) and other salts and clays, and are typically obtained by conventional shaft mining with the extracted ore ground into a powder. 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 Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...
. In above-ground processing plants, the KCl is separated from the mixture to produce a high-analysis potassium fertilizer. Other potassium salts can be separated by various procedures, resulting in potassium sulfate and potassium-magnesium sulfate.


Dissolution mining and evaporation methods

Other methods include dissolution mining and evaporation methods from brines. In the evaporation method, hot water is injected into the potash, which is dissolved and then pumped to the surface where it is concentrated by solar induced evaporation. Amine reagents are then added to either the mined or evaporated solutions. The amine coats the KCl but not NaCl. Air bubbles cling to the amine + KCl and float it to the surface while the NaCl and clay sink to the bottom. The surface is skimmed for the amine + KCl, which is then dried and packaged for use as a K rich fertilizer—KCl dissolves readily in water and is available quickly for plant nutrition. Recovery of potassium fertilizer salts from sea water has been studied in
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
. During extraction of salt from seawater by evaporation, potassium salts get concentrated in bittern, an effluent from the salt industry.


Production

Potash deposits are distributed unevenly throughout the world. , deposits are being mined in Canada, Russia, China, Belarus, Israel, Germany, Chile, the United States, Jordan, Spain, the United Kingdom, Uzbekistan and Brazil, with the most significant deposits present under the great depths of the Prairie Evaporite Formation in
Saskatchewan Saskatchewan is a Provinces and territories of Canada, province in Western Canada. It is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by the ...
, Canada. Canada and Russia are the countries where the bulk of potash is produced; Belarus is also a major producer. 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 (near the Carlsbad deposits), which is believed to be roughly 80% pure. ( Osceola County, Michigan, has deposits 90+% pure; the only mine there was converted to salt production, however.) Canada is the largest producer, followed by Russia and Belarus. The most significant reserve of Canada's potash is located in the province of Saskatchewan and is mined by The Mosaic Company, Nutrien and K+S. In
China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
, most potash deposits are concentrated in the deserts and salt flats of the endorheic basins of its western provinces, particularly
Qinghai Qinghai is an inland Provinces of China, province in Northwestern China. It is the largest provinces of China, province of China (excluding autonomous regions) by area and has the third smallest population. Its capital and largest city is Xin ...
. Geological expeditions discovered the reserves in the 1950s. but commercial exploitation lagged until
Deng Xiaoping Deng Xiaoping also Romanization of Chinese, romanised as Teng Hsiao-p'ing; born Xiansheng (). (22 August 190419 February 1997) was a Chinese statesman, revolutionary, and political theorist who served as the paramount leader of the People's R ...
's Reform and Opening Up Policy in the 1980s. The 1989 opening of the Qinghai Potash Fertilizer Factory in the remote Qarhan Playa increased China's production of potassium chloride sixfold, from less than a year at Haixi and Tanggu to just under a year.. In 2013, almost 70% of potash production was controlled by Canpotex, an exporting and marketing firm, and the Belarusian Potash Company. The latter was a joint venture between Belaruskali and Uralkali, but on July 30, 2013, Uralkali announced that it had ended the venture. Potash is water soluble and transporting it requires special transportation infrastructure.


Occupational hazards

Excessive respiratory disease due to environmental hazards, such as radon and asbestos, has been a concern for potash miners throughout history. Potash miners are liable to develop silicosis. Based on a study conducted between 1977 and 1987 of cardiovascular disease among potash workers, the overall mortality rates were low, but a noticeable difference in above-ground workers was documented.


Consumption


Fertilizers

Potassium is the third major plant and crop nutrient after
nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
and
phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...
. It has been used since antiquity as a
soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
fertilizer (about 90% of current use). Fertilizer use is the main driver behind potash consumption, especially for its use in fertilizing crops that contribute to high-protein diets. As of at least 2010, more than 95% of potash is mined for use in agricultural purposes. Elemental potassium does not occur in nature because it reacts violently with water. As part of various compounds, potassium makes up about 2.6% of the
Earth's crust Earth's crust is its thick outer shell of rock, referring to less than one percent of the planet's radius and volume. It is the top component of the lithosphere, a solidified division of Earth's layers that includes the crust and the upper ...
by mass and is the seventh most abundant element, similar in abundance to sodium at approximately 1.8% of the crust. Potash is important for agriculture because it improves water retention, yield, nutrient value, taste, color, 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. Demand for food and animal feed has been on the rise since 2000. The
United States Department of Agriculture The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and producti ...
'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 were 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. The world's largest consumers of potash are China, the United States, Brazil, and India.Supply and Demand
. Potassiodobrasil.com.br. Retrieved on 2013-06-21.
Brazil imports 90% of the potash it needs. Potash consumption for fertilizers is expected to increase to about 37.8 million tonnes by 2022. 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.


Pricing

At the beginning of 2008, potash prices started a meteoric climb from less than US$200 a tonne to a high of US$875 in February 2009. These subsequently dropped dramatically to an April 2010 low of US$310 level, before recovering in 2011–12, and relapsing again in 2013. For reference, prices in November 2011 were about US$470 per tonne, but as of May 2013 were stable at US$393. After the surprise breakup of the world's largest potash cartel at the end of July 2013, potash prices were poised to drop some 20 percent. At the end of December 2015, potash traded for US$295 a tonne. In April 2016 its price was US$269. In May 2017, prices had stabilised at around US$216 a tonne down 18% from the previous year. By January 2018, prices have been recovering to around US$225 a tonne. World potash demand tends to be price inelastic in the short-run and even in the long run.


Other uses

In addition to its use as a fertilizer, potassium chloride is important in many industrialized economies, where it is used in aluminium recycling, by the chloralkali industry to produce potassium hydroxide, in metal
electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric cur ...
, oil-well drilling fluid, snow and ice melting, steel heat-treating, in medicine as a treatment for hypokalemia, 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 Brewing is the production of beer by steeping a starch source (commonly cereal grains, the most popular of which is barley) in water and #Fermenting, fermenting the resulting sweet liquid with Yeast#Beer, yeast. It may be done in a brewery ...
beer Beer is an alcoholic beverage produced by the brewing and fermentation of starches from cereal grain—most commonly malted barley, although wheat, maize (corn), rice, and oats are also used. The grain is mashed to convert starch in the ...
, pharmaceutical preparations, and as a catalyst for
synthetic rubber A synthetic rubber is an artificial elastomer. They are polymers synthesized from petroleum byproducts. About of rubber is produced annually in the United States, and of that amount two thirds are synthetic. Synthetic rubber, just like natural ru ...
manufacturing. Also combined with
silica sand Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand—known as ''casting sand''—as the mold (manufacturing), mold material. The term "sand casting" can also refer to an object produced via th ...
to produce potassium silicate, sometimes known as waterglass, for use in
paints Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...
and
arc welding Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals, when cool, result in a joining of the metals. It is a type of welding that uses a welding power ...
electrodes. These non-fertilizer uses have accounted for about 15% of annual potash consumption in the United States.


Substitutes

No substitutes exist for potassium as an essential plant nutrient and as an essential nutritional requirement for animals and humans. Manure and glauconite (greensand) are low-potassium-content sources that can be profitably transported only short distances to crop fields.


See also

* Bone ash * Saltpeter * Saltwater soap *
Sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...


References

*


Further reading

* Seaver, Frederick J. (1918
"Historical Sketches of Franklin County And Its Several Towns"
J.B Lyons Company, Albany, NY, Section "Making Potash" pp. 27–29


External links




Henry M. Paynter, ''The First Patent'', Invention & Technology, Fall 1990


, issued for a method of potash production
World Agriculture and Fertilizer Markets Map


{{Authority control Agricultural chemicals Fertilizers Industrial minerals Potassium Salts Types of ash