Virtually all of the economic sources of potassium occur in sedimentary salt beds remaining after the evaporation of ancient seas and lakes. World reserves of such potassium-bearing deposits are immense and they total about 250 billion tons of K2O, of which 9.4 billion tons are considered commercially exploitable. With current global consumption of about 25 million tons of K2O annually both economical reserves and total resources are sufficient to satisfy world demand for centuries.
Location Of Potash Deposits
The potassium fertilizer industry originated in Western Europe where significant ores exist in several countries including Germany, France, Italy, Spain and the United Kingdom. Depletion of reserves is expected in the medium term in Spain, France and Germany.
North America, with the world’s greatest known reserves of potassium, is now the largest producing and exporting region in the world. The reserves are located in the Canadian province of Saskatchewan with smaller deposits in New Brunswick and Manitoba and also in the U.S.A. in the states of New Mexico, Utah, California and Michigan.
The former Soviet Union (FSU) has extensive proven reserves of potassium ore and prior to its division it was the world’s largest producer of potassium fertilizers.
In the Near East, potassium fertilizer salts are extracted from the Dead Sea in Israel and Jordan.
Small amounts of potassium fertilizer are obtained from brines in Qinghai Province of China and a substantial expansion in utilization of this is currently underway. Elsewhere in Asia, development work has started in the ore deposits of northeastern Thailand and the feasibility of utilizing another substantial source of potash in that country is being evaluated.
Reserves of potassium salts are limited in South America. Limited quantities of potassium fertilizer are produced in Brazil’s Sergipe Basin. The feasibility of producing potassium fertilizer in Argentina and from potash brine in Chile is currently under study.
Chile’s production of specialty potash products is based on its nitrate deposits. Capacity for production of potassium fertilizer salts is currently much in excess of world demand. For example in 1992, Canadian mines operated at close to 60 percent of capacity while those of the FSU functioned at 58 percent and other major world producers operated at levels of 80 to 95 percent.
Mining Of Potash Deposits And Production Of Fertilizers
At least 95 percent of world production of potassium fertilizers is in the form of potassium chloride. Potassium sulfate is the next most important source followed by much smaller quantities of specialty materials such as potassium magnesium sulfate, potassium nitrate, potassium thiosulfate, potassium polysulfide, potassium carbonate and potassium bicarbonate.
The potassium fertilizer industry originated in Western Europe with the world’s first potash factory being installed in Germany in 1857.
The existence of potassium-rich deposits in that country had been known several years earlier but manufacturing was delayed until processes were developed for separating potassium chloride from unwanted carnallite in the ore. Germany held a monopoly on potash production up to World War I and in the period immediately after this conflict. It continued to have a dominant role in potash even up to World War II.
At the end of these later hostilities and the political division of the nation, all aspects of the potash industry including production and marketing were separated. This split resulted in the German Democratic Republic (East Germany) becoming a slightly larger producer than the Federal Republic of Germany (West Germany). Upon reunification of the two Germanys in the early 1990s, a significant portion of the less efficient capacity in the former East Germany was closed.
However, Germany still remains the largest producer of potassium fertilizers in Western Europe.
France began production of potash in about 1910 and its capacity decreased in the early 1990s. Italy and Spain continue to be minor producers. The United Kingdom started production of potassium fertilizer from its difficult ore body in 1974.
Extensive reserves of high-grade potassium ores were discovered in the FSU in 1925. Prior to the separation of the FSU’s potash fertilizer industry into the Russian and Byleorussian sectors at the end of the 1980s, it had the world’s largest potash production capabilities.
Recovery of potassium salts from the Dead Sea in the Near East region was undertaken in 1931 and then discontinued in 1947. Israel first began to extract potassium fertilizer salts from the Dead Sea in 1952 while Jordan initiated its operations to exploit the same source in 1983.
1979 was the first time that production of small amounts of potassium fertilizer was recorded in China. Production continued at modest levels through the 1980s with a significant increase in capacity planned for 1997 or 1998.
Africa and Asia (excluding China) are now without potash fertilizer production capability. Limited production in northeastern Thailand is anticipated after 1998. Reserves of potassium salts are modest in South America where production of small amounts of potassium fertilizer began about 1986 in Brazil’s Sergipe Basin. There is a strong possibility that potassium fertilizer manufacturing will be started in Argentina shortly before the year 2000. The feasibility of producing potash fertilizer from brine in Chile is being evaluated. Chile’s current production of specialty potassium fertilizers is based on its nitrate deposits.
Potash Production And Consumption In The United States
Potash was an important component of U.S. fertilizers in the years 1870 to 1920. At the beginning of this period, the only obtainable sources, in limited amounts, were tobacco stems, wood ashes, cotton hulls and cotton boll ashes. The potash supply situation improved in about 1875 with importation of potash salts from Germany. By 1890, the German supplies dominated all other sources, and they continued to do so until 1914, at
the beginning of World War I hostilities. These German imports ceased in 1917 when the U.S. entered the War.
During the World War I years of 1914 to 1918, a wide variety of potash sources were utilized including
brines from Searles Lake, California; alunite (a potassium aluminum sulfate mineral) from Utah; brines from lakes in Western Nebraska
salty waters from Great Salt Lake
dust from cement kilns
wastes from distilleries and sugar refineries
kelp harvested off the shores of California and other materials of lesser importance.
The brines represented 73 percent of the potash produced in these years.
An intense search for domestic supplies of potash began in 1910 in an attempt to become independent of the German potash monoply. The German potash embargo in World War I heightened this search. These hunts lead to the discovery of the New Mexico potash beds in 1925. Further exploration clearly identified the existence of a substantial deposit of potash salts and between 1932 and 1935 a thriving potash fertilizer industry founded on these deposits was established. Also it marked the beginning of an extended period of potash independence lasting from 1935 to 1966.
Before 1935, domestic production of potassium fertilizer was restricted mainly to Searles Lake and a number of smaller operations based primarily on recovery of byproduct potash and low-grade products from brines.
By 1966, seven potash mines in New Mexico and one in Utah were being operated. Potassium fertilizers were also being produced from the Searles Lake brines by two companies and by one other operation at the Salduro Marsh in Utah. Domestic production reached an all-time high in 1966 and it has declined steadily since that time.
This reduction was due to two important factors including the quality and competitiveness of the New Mexico ores and the impact of the newly established Canadian potash industry.
Recovery of potassium salts from the natural brines of Great Salt Lake was initiated in 1970. A major expansion scheduled for completion in 1996 will approximately double potash fertilizer production capacity at this source.
In the mid-1990s, the centers of potash fertilizer production were located in New Mexico, Utah, California and Michigan. Approximately 80 percent of the total production capacity existed in New Mexico.
As early as 1937, potassium chloride accounted for 85 percent of the total U.S. potash consumption and since then its popularity has increased to the point that it now represents 94 to 95 percent of total potash usage in this country.
In the late 1970s, 84 percent of the total U.S. potash fertilizer production was in the form of potassium chloride with the remainder being principally potassium sulfate and potassium magnesium sulfate.
U.S. consumption of potash has grown significantly from 239,000 tons of K20 in 1934, to 1.10 million tons of K2O in 1950, to 2.15 million tons of K2O in 1960 and reached a maximum of 6.32 million tons of K2O in 1981. In the first four years of the 1990s, usage has ranged between 5.00 and 5.27 (in 1994) million tons of K2O.
Potash Production In Canada
The potash deposits discovered in Saskatchewan in 1943 are believed to be the greatest reserves of high-grade potassium reserves in the world. Mining of these ores commenced in 1962 and production capacities were expanded in the 1970s and 1980s.
Substantial quantities of the potassium chloride produced from these immense deposits soon began to be exported to the U.S. and by 1966 these exports comprised 38 percent of total consumption and this figure was 79 percent in 1980.
Because global capacity for production of potassium fertilizer salts has for many years been in excess of world demand, the Saskatchewan mines have at times operated at much below capacity, as low as 45 percent or less. In 1992, the nine mines in Saskatchewan operated at close to 60 percent. By way of comparison, the U.S. potash industry ran at 84 percent in 1992 and 92 percent in 1993.
The potash ore in Saskatchewan is extracted by dry mining methods at seven of its nine mines while solution mining is used at the two remaining mines.
In addition to the extensive potash mining and fertilizer production in Saskatchewan, there are now two potash fertilizer production facilities in the Atlantic province of New Brunswick. The high-grade ores in that province were found in 1971. The first of the two mines came on-stream in 1983 followed by the second in 1984. Of the total Canadian potash fertilizer production capacity of 13.11 million tons of K2O, New Brunswick accounts for about 1.43 million tons or 11 percent.
Efficient Fertilizer Use — A Historical Perspective: by Dr. James Beaton