Canada is the largest producer of potash in the world. Recent investment in the development of potash resources in Saskatchewan is raising the usual issues of economic prosperity vs environmental sustainability. As potash is becoming a larger part of the Canadian economy I thought that I would share what I learned about potash because I knew essentially nothing about it until recently.
Before the late 1800s, potash was produced by leaching salts from the ashes of wood or plants and boiling the solution in a pot, hence the name potash. Historically, Canada was a large producer of potash as the frontier was opened up and deforested. Excess wood was burned and brought to asheries, where the ash was converted to potash.
Modern methods exist to obtain potash from mineral deposits and Canada has the largest reserves of these deposits in the world. The deposits are the result of the complete evaporation of sea water and the deposition of crystallized salts in beds of ore, called sylvinite. This ore consists of a mixture of sodium and potassium chloride (NaCl and KCl). The KCl is then purified using various processes and sold as potash.
Due to historical methods of production potash can refer to various salts of potassium, however mined potash is largely KCl. The element potassium derives its name from potash.
The majority of potash is used in fertilizers. Plant growth is often limited by available potassium. Therefore there is no substitute for potash and in a world of seven billion it is essential for food production. The best we can do is ensure that Canada responsibly extracts this valuable resource.