Potassium

The greatest use for potassium is as a fertilizer because it is an essential element to plant growth.   An alloy of sodium and potassium, NaK, is used as a heat transfer medium in nuclear reactors.   Important potassium salts are the following

Potassium hydroxide (caustic potash, lye), KOH, was used to make soap by steeping wood ashes in water for a long period of time before synthetic chemicals replaced this use.   It is a major industrial chemical used as a base in many of chemical processes.   It is used as a catalyst in reactions, such as the production of biodiesel fuel, acrylate ester copolymer coating, defoaming agents used in the manufacture of paper, formulation aid for food, pH control agent, polyethylene resins, and textile production.   Potassium hydroxide is used for washing and chemical peeling of fruits and vegetables, chocolate and cocoa processing, caramel coloring, poultry scalding, forming a skin on pretzels before baking, olive aging, soft drink processing, ice cream thickening, veterinary medicine in disbudding calves horns and dissolving scales and hair, manufacturung cleansers, wart removal, cuticle solvent, washing powders, denture cleaners, non-phosphate detergents, and drain or pipe cleaners. ^{Wiki n.p.}   KOH was easily extracted since ancient times by soaking wood ashes in water.   Industrial methods of caustic soda production developed in the 18th century, e.g., the Leblanc process, and 19th century (Solvay, or ammonia-soda, process) have been largely displaced by electrolysis. ^{B'nica n.p.}

Potassium nitrate, KNO₃, (saltpeter, Chilean saltpeter, niter).   It is the oxidizing component of gunpowder, used to produce nitric acid, used as a fertilizer, as a rocket propellant, and for pyrotechnics. ^{Wiki n.p.}

Potassium carbonate, K₂CO₃, (pearl ash, salts of tartar) is used to manufacture soft soaps and glass, for washing wool, and to produce other potassium compounds.

Potassium chloride, KCl, as pills are a source of potassium and a substitute for salt, NaCl, for people on a salt-restricted diet.

Potassium chlorate, KClO₃ is used in matches, fireworks, and explosives, and as a disinfectant and bleaching agent.

Potassium bromide, KBr, is used by veterinarians as an anticonvulsant medicine for dogs.

Potassium iodide, KI, is used in radiation therapy to block effects on the thyroid gland.

Potassium cyanide, KCN, is used in electroplating and photography.   It is extremely toxic.

Potassium sulfate, KSO₄, is an important fertilizer.

Potassium permanganate, KMnO₄, is used is powerful oxidizing agent, disinfectant, and cure for some fish diseases.

Potassium is essential to life.   Potassium cation, K⁺, is used to regulate concentration of substances within animal cells, used for proper nerve action, and carbohydrate, protein, and fat energy release.   Sources: orange juice, bananas, dried fruits, meats, bran, peanut butter, dried beans and peas, potatoes, coffee, tea, cocoa.   A deficiency is uncommon, but when occurring, it can result in abnormal heartbeat, muscular weakness, lethargy, kidney and lung failure when it occurs. ^{Brody 185}   Because potassium is important for plant growth, but is not always available in sufficient quantities, it is often added to the soil as a fertilizer.

In plants, potassium is necessary for formation of sugars, starches, carbohydrates, protein synthesis and cell division.   It helps to adjust water balance, improves stem rigidity and cold hardiness, enhances flavor and color on fruit and vegetable crops, increases the oil content of fruits and is important for leafy crops.   Deficiencies result in low yields, mottled, spotted or curled leaves, and a scorched or burned look to leaves. ^{Morgan n.p.}

Potassium was discovered by Humphry Davy, a British chemist, in 1807, who obtained it from caustic potash, KOH.   It was the first metal obtained by electrolysis.   Because of its high reactivity, potassium is never found free in nature.   Most of the potassium minerals are insoluble, so potassium is difficult to obtain, although it is the seventh most abundant metal found on earth.   Certain potassium-bearing minerals, viz., sylvite, carnallite, langbeinite, and polyhalite are found in ancient lake and sea beds, from which potassium and its salts can be obtained readily.   It is obtained by electrolysis of its hydroxide.   Thermal methods also are used to produce the metal; viz., reduction of potassium compounds with CaC₂, carbon, silicon, or sodium. ^{Lide 4-22}