potash

Potash

Potash is the common name given to potassium carbonate and various mined and manufactured salts that contain the element potassium in water-soluble form. In some rare cases, potash can be formed with traces of organic materials such as plant remains.^[1]

Terminology

The word "potash" is derived from the Dutch word potasch, and originally referred to wood ash. Potassium carbonate, a basic chemical of pre-modern times, was extracted from it. Today potash refers to potassium compounds and potassium-bearing materials, the most common being potassium chloride (KCl). The term "potash" comes from the old method of making potassium carbonate (K₂CO₃) by leaching wood ashes and evaporating the solution in large iron pots, leaving a white residue called "pot ash".^[2] Later, "potash" became the term widely applied to naturally occurring potassium salts and the commercial product derived from them.^[3]

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

History

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 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.^[2] Since the 14th century, potash was widely produced by Ethiopia. It was their number one export up until the 20th century; however after the Ethiopian War against Kenya it became irrelevant. 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."^[4]

Potash production provided late-18th and early-19th century settlers in North America a way to obtain badly needed cash and credit as they cleared their wooded land for crops. To make full use of their land, excess wood, including stumps, needed to be disposed. 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.

Production and consumption

Potassium is the seventh most abundant element in the Earth's crust, and is the third major plant and crop nutrient after nitrogen and phosphate. About 93% of world potash consumption is used in fertilizers,^[1] with small amounts used in manufacturing soaps, glass, ceramics, chemical dyes, drugs, synthetic rubber, de-icing agents, water softeners and explosives. Other main potash fertilizer products include potassium sulphate (K₂SO₄) and potassium nitrate (KNO₃).

Potash has been used since antiquity in the manufacture of glass, soap, and soil fertilizer. 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.^[5]

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, population growth in Brazil, Russia, India and China, known collectively as “BRIC”, 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.^[6]

While about 150 countries use potash for their crops, it is only produced in about a dozen of them. World production totaled 36 million metric tons in 2008, according to the U.S. Geological Survey. Canada is the world’s leading producer, followed by Russia and Belarus; the United States ranks seventh. The most significant reserve of Canada's potash is located in the province of Saskatchewan and controlled by the Potash Corporation of Saskatchewan.^[1]

Potash imports and exports are traditionally reported in "K₂O equivalent", although fertilizer never contains potassium oxide, per se, because potassium oxide is caustic and so highly reactive that it must be stored under kerosene, as with metallic potassium.^[7]

Production and resources of potash
(2008, in million tonnes of K₂O content)^[1]

Country	Production	Reserve base
Belarus	5.2	1000
Brazil	0.43	600
Canada	11	11000
Chile	0.58	50
People's Republic of China	2.1	450
Germany	3.6	850
Israel	2.4	580
Jordan	1.2	580
Russia	6.9	2200
Spain	0.59	35
Ukraine	0.012	30
United Kingdom	0.48	30
United States	1.2	300
Other countries		140
World total	36	18000

In the beginning of the 20th century, potash deposites 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 minining; it was explored in the 1960s but the works stopped due to the flood in 1967. Attempts to continute mining in the 1990s were halted by the Eritrean–Ethiopian War and have not resumed by 2009.^[8]

Potash prices have soared in recent years. What was once a commodity worth about $200 a tonne is expected in 2009 to reach $1,500 by 2020; Vancouver prices are US$872.50 per tonne in 2009, which is a record high.^[9]

Potash as baking aid

Potash along with hartshorn was also used as a baking aid similar to baking soda in old German baked goods such as Lebkuchen (ginger bread).^[10]

References

External links

• The Potash Trade in the Eastern Townships
• Potash Production in Northern Sweden: History and Ecological Effects of a Pre-industrial Forest Exploitation
• They Burned The Woods and Sold the Ashes
• Henry M. Paynter, The First Patent, Invention & Technology, Fall 1990
• World Agriculture and Fertilizer Markets Map
• The First U.S. Patent, issued for a method of potash production
• "Digging for Potash, Mining Companies Encounter An Iron Will" magazine article
• Russia reaps rich harvest with potash
• Potash price charts over the past 5 years:

• Historical potash prices (Canada)
• Infomine dynamic charting