Potassium

Potassium is a key ingredient for the manufacture of agricultural fertiliser, making it a critical mineral for food security.

Potassium (K)

Potassium is the seventh most abundant metal in the Earth’s crust and the lightest after only lithium. Its elemental form is silvery in colour and soft enough to cut with a knife, but as it is highly chemically reactive, it does not naturally occur in its elemental form. Common potassium compounds are typically salts, including potassium chloride (KCl) and various carbonates, nitrates, and sulphates. Potassium is also an essential macronutrient for humans that is necessary for the maintenance and growth of tissues, muscles, and organs. The vast majority of potassium is used to manufacture fertilisers, but it can also be used to produce detergents, dyes, explosives, glass, and solvents.

Potassium-bearing minerals and refined potassium products, such as fertilisers, are generally referred to as potash. Potash generally contains between 20 and 35 percent of KCl, with the remainder primarily composed of other potassium salts. The ores are most commonly mined to obtain potassium compounds are sylvite, carnallite, kainite, langbeinite, and polyhalite.

Potassium production and reserves are not consistently reported with the same methodology for each country, so the volumes are usually stated in terms of the equivalent amount of potassium oxide (K₂O). Canada, Russia, and Belarus accounted for approximately 70% of the world’s potash production in 2022, with Brazil and Canada holding the largest known reserves, each with an estimated 1.1 billion tonnes of K₂O equivalent. Israel and Jordan both recover potash from the huge reserves of potassium salts in the Dead Sea, which contains approximately 2 billion tonners of KCl.

Public information on ESG issues in the potassium supply chain is limited, with only low materiality ESG issues identified. The most notable issue identified relates to the exploration of the recently discovered largest potash deposit in Brazil, in which a Canadian-owned mining company is drilling on or near land that is owned by the indigenous Mura people in the state of Amazonas. Local residents allege that logging and drilling is being carried out without their full, prior and informed consent, however the formal legal designation of the affected land as an indigenous territory is unclear.

Main uses and applications

In addition to its high chemical volatility, which causes it to readily form compounds with other materials, potassium has a low melting point and both a high electrical and thermal conductivity. Its high reactivity is utilised in respiratory equipment as potassium superoxide (KO₂) removes carbon dioxide and water vapour from air while simultaneously liberating oxygen. Potassium is immiscible with many metals, meaning that it is incapable of mixing or attaining homogeneity, which limits its utility in forging alloys.

There is little commercial demand for potassium metal, with approximately 95 percent of mined potash used as an input into fertiliser manufacturing. Potassium, along with nitrogen and phosphorus, is an essential nutrient in agriculture and horticulture as it can strengthen plants’ root systems and resistance to disease, thus increasing crop yields and quality.

Potassium cyanide can be used to extract gold from low grade ore and tailings waste. Potassium chromate is used in leather production processes and dyeing textiles and potassium carbonate can be used to manufacture glass. Potassium hydroxide can be obtained by the electrolysis of sylvine (the natural mineral form of KCl) and is commonly used to manufacturer soaps and detergents. Other economically significant potassium compounds are potassium nitrate – which is utilised to produce fertilisers, fireworks, and explosives.