Potash
Potash (or
carbonate of potash) is an impure form of
potassium carbonate (
K2CO3) mixed with other
potassium salts. Potash has been used since
antiquity in the manufacture of
glass and
soap, and as a
fertilizer. The name comes from the
English words
pot and
ash, referring to its
discovery in the
water-
soluble fraction of
wood ash.
It is today principally produced by
mining suitable deposits which are found throughout the world.
The term has become somewhat ambiguous due to the
substitution in fertilizers of cheaper
potassium salts such as
potassium chloride (
KCl) or
potassium oxide (
K2O), to which the same common name is now sometimes also applied. In addition,
potassium hydroxide (
KOH) is commonly called "caustic potash", an additional source of confusion.
The element
potassium derives its English name from potash. A number of chemical compounds containing potassium use the word
potash in their traditional names:
::
Potash Production and Trade
Until the
20th century, potash was one of the most important industrial chemicals in
Europe. It was produced primarily in the forested areas of Europe, in
Russia and in
North America, refined from the ashes of broadleaved trees.
Potash production provided late
18th and early
19th century settlers in North America a way to obtain badly needed cash and credit while they were in the process of clearing their wooded land for crops. To make full use of their land, excess wood, including stumps needed to be disposed of. The easiest way to accomplish this was to burn any wood not needed for fuel or construction. Ashes from
hardwood trees could then be used to make
lye, which could either be used to make soap or boiled down to produce valuable potash. Hardwood could generatate ashes at the rate of 60 to 100
bushels per acre (500 to 900 m³/km²). In 1790 ashes could be sold for $3.25 to $6.25 per acre ($800 to $1500/km²) in rural
New York State, nearly the going rate for hiring a laborer to clear that same area.
If desired, the potash could be further refined by baking in a
kiln to produce a less impure form of potassium carbonate, known as pearlash for its pearly white color. This step was commonly performed at a nearby
ashery. The refined postash was in increasing demand in
Europe for use in the production of
glass and ceramic goods. American hardwoods, besides being more abundant, are said to have provided a higher yield of quality potash than European wood. In some parts, potash receipts became a common form of
currency. Some settlers found potash production to be quite lucrative, resulting in faster
deforestation than farming alone would have caused.
The first U.S. Patent was issued in 1790 to
Samuel Hopkins for an improvement "in the making Pot ash and Pearl ash by a new Apparatus and Process."
Today, only 12 countries produce the world's supply of potash. The main producers are North America, the
Middle East, Russia and
Belarus. Many other areas, however, have the resources for potash production.
External links
de:Kaliumcarbonat
fr:Potasse
pl:Pota%C5%BC
ru:Поташ
Category:Minerals