Potassium History

Potassium was discovered in 1807 by Sir Humphrey Davy, who derived it from caustic potash (KOH). Potassium was the first metal that was isolated by electrolysis.

Potassium was not known in Roman times, and its names are not Classical Latin.
The name kalium was taken from the word "alkali", which came from Arabic al qalīy = "the calcined ashes".
The name potassium was made from the word "potash", which is English, and originally meant an alkali extracted in a pot from the ash of burnt wood or tree leaves.



Potassium makes up about 2.40% of the weight of the Earth's crust and is the seventh most abundant element in it. As it is very electropositive, potassium metal is difficult to obtain from its minerals.

Potassium salts such as carnallite, langbeinite, polyhalite, and sylvite are found in ancient lake and sea beds. These minerals form extensive deposits in these environments, making extracting potassium and its salts more economical. The principal source of potassium, potash, is mined in California, Germany, New Mexico, Utah, and in other places around the world. 3000 feet below the surface of Saskatchewan are large deposits of potash which are important sources of this element and its salts, with several large mines in operation since the 1960's. Saskatchewan pioneered the use of freezing of wet sands (the Blairmore formation) in order to drive mine shafts through them. See Potash Corporation of Saskatchewan. The oceans are another source of potassium, but the quantity present in a given volume of seawater is relatively low compared to sodium.

Potassium can be isolated through electrolysis of its hydroxide in a process that has changed little since Davy. Thermal methods also are employed in potassium production, using potassium chloride. Potassium is almost never found unbound in nature. However, in living organisms K+ ions are important in the physiology of excitable cells.