Potash is a potassium-rich salt that is mined from underground deposits formed from evaporated sea beds millions of years ago. Potassium is an essential element for all plant, animal and human life. The term "potash" refers to a group of potassium (K) bearing minerals and chemicals.

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Potash
Introduction:
 Potassium (K) is an alkali metal with the atomic number of 19 and a molar mass of 39.0983 gmol−1. It is one
of the seven most abundant elements in the Earth’s crust at about 2.6%, and the 20th most abundant element in the
universe.
 It is exceedingly reactive, so is never found as a pure metal, and must be stored in oil to prevent it from
reacting violently with water vapour in air.
 It is commonly found in the form of salts such as potassium chloride (KCl), potassium nitrate (KNO3) and
potassium carbonate (K2CO3), which are typically ionic in nature and relatively soluble in water. It is also found in
feldspars and micas.
 Potash is mined worldwide to provide potassium, an essential nutrient for food crops. Evaporite-hosted potash
deposits are the largest source of salts that contain potassium in water-soluble form, including potassium chloride,
potassium-magnesium chloride, potassium sulphate, and potassium nitrate.
 Potash minerals are found in large evaporite deposits from ancient lakes and sea beds, or in rock formations.
Thick sections of evaporitic salt that form laterally continuous strata in sedimentary evaporite basins are the most
common host for stratabound and halokinetic potash bearing salt deposits.
 The top potash-producing countries include Canada, Belarus and Russia. Example of famous potash bearing
basins are the Elk Point Basin in Canada, the Pripyat Basin in Belarus, the Solikamsk Basin in Russia, and the
Zechstein Basin in Germany.
1. Types of Potash ore:
Sylvite:
Sylvite, is the mineral name for potassium chloride (KCl). Sylvite is the most common form of potash, with massive
deposits found in the US. However, the largest-known deposits of sylvite come from Devonian evaporite basins in
Saskatchewan, Canada.
KCl is also known as muriate of potash (MOP). MOP is the most commonly used fertilizer, and is particularly helpful
for chloride-loving vegetables such as sugar beets, corn, celery and Swiss chard. It can be beneficial for soil that is low
in chloride, building disease resistance in plants.
Polyhalite:
Chloride is toxic to some fruits and vegetables, and in those cases, farmers use polyhalite instead of MOP(Sylvite).
Polyhalite is a potash mineral that contains the key nutrients potassium and sulphur.
Polyhalite is known to the market as sulfate of potash (SOP), and is the second most commonly used form of potash.
Global annual production of SOP comes in at roughly 6 million MT.
SOP makes plants more resilient to drought, frost, insects and even disease, which in turn improves plant quality and
crop yields. SOP can also improve the look and taste of foods, and a plant’s ability to absorb essential nutrients like
phosphorus and iron.

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Langbeinite:
Langbeinite is a potassium magnesium form of potash; however, it also contains sulphate, giving it the name sulphate
of potash magnesia (SOPM).
Similar to SOP, this variation of potash is used for chloride-sensitive fruit and vegetable crops, but particularly where
there is a magnesium deficiency in the soil. SOPM is primarily a magnesium fertilizer, so it is a niche market within
the larger the industry.
Carnallite:
Carnallite is made up of potassium chloride, magnesium and water, however, these compounded minerals make it a
tricky mineral from which to extract potash fertilizer. As a result, it is a good type of potash to use only when there is
no source of sylvite or Sylvinite. Carnallite is mined for both its potash and magnesium properties.
2. Potash deposit types
Stratabound potash-bearing salt: Stratabound potash deposits hosted by relatively flat-lying and undeformed salt
rock and related wide basin evaporite deposits. Stratabound potash-bearing salt is associated with thick sections of
evaporitic salt (halite) that form laterally continuous strata in marine evaporite basins. Deposits are extremely soluble
and thus easily altered or destroyed over geologic time. Stratabound potash deposits range in size from several tens of
millions to more than 30 billion metric tons of potassium oxide (K2O). Most of the world’s potash resources are
associated with this deposit type.
Halokinetic potash-bearing salt: Halokinetic potash-bearing salt occurs in salt structures developed from
stratabound potash-bearing salt deposits. Potash deposits in salt rock and associated evaporites that have been
deformed by salt flow into salt domes and other salt structures. Within these structures, the potash mineralization is
commonly disrupted and deformed with repeated, thickened, and (or) thinned bedding, or even the total loss of potash
mineralization.
Mixed stratabound and halokinetic potash-bearing salt: Potash deposits with characteristics transitional between
stratabound potash-bearing salt and halokinetic potash-bearing salt or with characteristics of both types.
Potash-bearing brine: Near-surface brine-dominated systems in closed continental basins enriched in potassium and
other commodities; commonly Pliocene to Quaternary in age.
Evaporite Potash deposits: Evaporite-hosted potash deposits are the largest source of salts that contain potassium in
water-soluble form, including potassium chloride, potassium-magnesium chloride, potassium sulphate, and potassium
nitrate. Thick sections of evaporitic salt that form laterally continuous strata in sedimentary evaporite basins. The term
‘sabkha’ was originally used exclusively for the description of salt flats in coastal desert settings. Sabkha
sedimentation usually involves interactions between chemical (precipitate) and aeolian processes, and results in the
generation of a variety of wavy and crinkly laminae that are often disturbed by salt growth structures such as
‘teepees’. Salt precipitation in sabkhas requires periodic wetting and subsequent desiccation of the surface, and is
often controlled by subtle water table changes which, in coastal settings, may be driven by sea-level change. A wide
variety of evaporite minerals are forming in these sabkhahs, and studies of currently active geochemical processes
involved in formation of minerals such as deposition of dolomite and transition of gypsum to anhydrite under near-
surface conditions.
3. Potash 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) and Sodium Chloride (NaCl) and are generally
obtained by conventional shaft underground mining, with the extracted ore ground into a powder. Other method
includes dissolution mining and evaporation methods from brines.

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Conventional underground mining:
Shaft mines are most well-known underground mining which involves around 1,000 metres below ground level.
Shafts are used to move miners and equipment from ground level to the underground site. Potash is mined using two
and four rotor continuous boring machines. Conveyor belts carry ore to underground bins where it is stored until it is
transported to the loading pocket of the shaft hoist. Potash ore is hoisted to the surface in ore skips. A process plant
separates the salt from the potash and converts the potash to the final product, ready for storage & shipping. As these
are soluble deposits, mining takes place underground, often at depths of 1,000 m or greater, so deposits must be
protected from groundwater intrusions, shafts are commonly lined with concrete and steel shields to prevent the influx
of water.
Figure 1: Underground Mining
Conventional solution mining
Solution mining entails the injection of brine solutions into underground potash-bearing or other salt seams. The
solution dissolves soluble potash-bearing minerals from the seam, and the pregnant potash-bearing solution is then
recovered to the surface for processing. The dissolved salts are then pumped out of the cavern to the surface where the
water is evaporated, either artificially or in solar evaporation ponds; salt and potash are left behind. This "left-over"
salt and potash is then removed from the pond and transported to a processing facility where the potash is separated
from the salt and refined for sale.
Solution mining can substitute for conventional shaft mining in some potash deposits at depths of more than 1,100m,
which is the current limit for conventional potash mining.
The solution mining operations, focused specifically on potash recovery, thickness, mineralogy, and structure/ore-
continuity, as well as other technical considerations of the mining operation, must be evaluated to determine the
suitability of solution mining.
Solution mining offers a few advantages compared to conventional underground mining including lower up-front
capital cost and a shorter ramp-up time. As all mining methods, the profitability of a solution mine is affected by the
mineralogy, grade and tonnage of the potash reserve. Solution mining costs are directly related to drilling cost and the
quantity of potash produced from each well.

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Figure 2: Solution Mining
4. Uses:
Potash is used primarily in fertilizers (approximately 95%) to support plant growth, increase crop yield and disease
resistance, and enhance water preservation. Small quantities are used in manufacturing potassium-bearing chemicals
such as:
 Detergents
 Ceramics
 Pharmaceuticals
 Water conditioners
 Alternatives to de-icing salt
Potassium is an essential element of the human diet, required for the growth and the maintenance of tissues, muscles
and organs, as well as the electrical activity of the heart.
5. Overview on Indian Potash (Source: IBM Year Book 2020):
 In India, main potash mineral is Glauconite. Glauconite is essentially a complex hydrous silicate of
iron and potassium chiefly with ferric oxide and partly with ferrous oxide. It contains about 4–7% K2O.
 As per NMI database, based on UNFC system, the total resources of potash as on 1.4.2015 have been
estimated at 22,508 million tonnes, all of which are placed under Resource category. Rajasthan alone
contributes 91% to the total resources, followed by Madhya Pradesh (5%) and Uttar Pradesh (4%).
 91% of resources are located in Nagaur district of Rajasthan, followed by Panna district, Madhya
Pradesh (5%) and the balance in Sonbhadra & Chitrakoot districts, Uttar Pradesh (4%).
 Occurrences of potash are also reported from Tirap district of Arunachal Pradesh; Rohtas district of
Bihar; Kachchh district of Gujarat; Rohtak & Sirsa districts of Haryana; Leh district of Jammu & Kashmir;

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Sidhi district of Madhya Pradesh; Bhilwara & Nagaur districts of Rajasthan; Tanjavur district of Tamil Nadu
and Banda, Chitrakoot, Sonbhadra & Etah districts of Uttar Pradesh.
 In Rajasthan, glauconitic sandstones/shales occur in Chittorgarh, Kota, Karauli, Jaisalmer and Barmer
districts. In Gujarat, glauconite is found in Ukra Formation at Guneri in Kachchh district. In Himachal Pradesh,
glauconite of hydrothermal origin is found in Kumla-Kathwar area of Sirmaur district. In Kerala, glauconite
occurs in Quilon Limestone and seabed sediments of Thiruvananthapuram coast.
6. Worldwide distribution of proven potash reserves in 2020:
The world reserves are estimated at approximately 3,700 million tonnes of K2O content. Reserves are located mainly
in Canada (30%), Belarus (20%), Russia (16%), China (9%), USA (6%), Germany (4%) and Chile (3%).
Figure 3: World Potash Reserves

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Figure 4: World Reserves of Potash (Source IBM Year Book-2020)
7. World production of potash (Year 2021):
Figure 5: Potash Production Table