Editing Potassium nitrate (section)

==Historical production==<!-- This section is linked from [[Gunpowder]] and from [[Urine]]-->
{{See also|Nitre#Availability}}

===From mineral sources===
In [[Maurya Empire|Mauryan India]] saltpeter manufacturers formed the Nuniya & Labana
[[caste]].<ref>{{cite book |last = Sen |first = Sudipta |date = 2019 |isbn = 978-0-300-11916-9 |page = 318 | title = Ganges: The Many Pasts of an Indian River |location = New Haven |url = https://books.google.com/books?id=FOV8DwAAQBAJ&pg=PT695 |publisher = Yale University Press}}</ref> Saltpeter finds mention in [[Kautilya|Kautilya's]] [[Arthashastra]] (compiled 300BC – 300AD), which mentions using its poisonous smoke as a weapon of war,<ref>{{cite book |last = Roy |first = Kaushik |date = 2014 |title = Military Transition in Early Modern Asia, 1400–1750 |page = 19 |isbn = 978-1-7809-3765-6 |location = London |publisher = Bloomsbury Academic |url = https://books.google.com/books?id=KyVnAwAAQBAJ&pg=PA19}}</ref> although its use for propulsion did not appear until medieval times.

A purification process for potassium nitrate was outlined in 1270 by the chemist and engineer [[Hasan al-Rammah]] of [[Syria]] in his book ''al-Furusiyya wa al-Manasib al-Harbiyya'' (''The Book of [[furusiyya|Military Horsemanship]] and Ingenious War Devices''). In this book, al-Rammah describes first the purification of ''barud'' (crude saltpeter mineral) by boiling it with minimal water and using only the hot solution, then the use of [[potassium carbonate]] (in the form of [[wood ash]]es) to remove calcium and magnesium by precipitation of their carbonates from this solution, leaving a solution of purified potassium nitrate, which could then be dried.<ref>[[Ahmad Y Hassan]], [http://www.history-science-technology.com/Articles/articles%202.htm Potassium Nitrate in Arabic and Latin Sources] {{webarchive|url=https://web.archive.org/web/20080226105129/http://www.history-science-technology.com/Articles/articles%202.htm |date=2008-02-26}}, ''History of Science and Technology in Islam''.</ref> This was used for the manufacture of gunpowder and explosive devices. The terminology used by al-Rammah indicated the gunpowder he wrote about originated in China.<ref>{{cite book|author=Jack Kelly|title=Gunpowder: Alchemy, Bombards, and Pyrotechnics: The History of the Explosive that Changed the World|url=https://books.google.com/books?id=8xfs8tC8Ow0C&pg=PA22|year=2005|publisher=Basic Books|isbn=978-0-465-03722-3|page=22|url-status=live|archive-url=https://web.archive.org/web/20160511041453/https://books.google.com/books?id=8xfs8tC8Ow0C&pg=PA22|archive-date=2016-05-11}}</ref>

At least as far back as 1845, [[nitratite]] deposits were exploited in Chile and California.

===From caves===
Major natural sources of potassium nitrate were the deposits crystallizing from cave walls and the accumulations of [[bat guano]] in caves.<ref>{{cite book |title=Notes on Making Saltpetre from the Earth of the Caves |author=Major George Rains |year=1861 |page=14 |publisher=Daily Delta Job Office |location=New Orleans, LA |access-date=September 13, 2012 |url=https://archive.org/stream/notesonmakingsal01rain |url-status=live |archive-url=https://web.archive.org/web/20130729072115/https://archive.org/stream/notesonmakingsal01rain |archive-date=July 29, 2013}}</ref> Extraction is accomplished by immersing the guano in water for a day, filtering, and harvesting the crystals in the filtered water. Traditionally, guano was the source used in [[Laos]] for the manufacture of gunpowder for [[Rocket Festival|''Bang Fai'']] rockets.<ref name="joshi14">{{cite journal |doi=10.56431/p-je383z |title=Environmentally and Economically Feasibility Manufacturing Process of Potassium Nitrate for Small Scale Industries: A Review |date=2014 |last1=Joshi |first1=Chirag S. |last2=Shukla |first2=Manish R. |last3=Patel |first3=Krunal |last4=Joshi |first4=Jigar S. |last5=Sahu |first5=Omprakash |journal=International Letters of Chemistry, Physics and Astronomy |volume=41 |pages=88–99 |doi-access=free}}</ref>

[[Calcium nitrate]], or lime saltpetre, was discovered on the walls of stables, from the urine of barnyard animals.<ref name=brit1/>

=== Nitraries ===<!-- Redirect from [[Nitrary]] -->
{{See also|Saltpetre works}}
Potassium nitrate was produced in a ''nitrary'' or "[[saltpetre works]]".<ref>{{cite book|author1=John Spencer Bassett|author2=Edwin Mims|author3=William Henry Glasson |author4=William Preston Few |author5=William Kenneth Boyd |author6=William Hane Wannamaker|display-authors=3|title=The South Atlantic Quarterly|url=https://books.google.com/books?id=j7p9AAAAMAAJ&q=nitraries|access-date=22 February 2013|year=1904|publisher=Duke University Press}}</ref> The process involved burial of excrements (human or animal) in a field beside the nitraries, watering them and waiting until leaching allowed saltpeter to migrate to the surface by [[efflorescence]]. Operators then gathered the resulting powder and transported it to be concentrated by [[ebullition]] in the boiler plant.<ref>{{cite book |author=Paul-Antoine Cap |title=Etudes biographiques pour servir à l'histoire des sciences ...: sér. Chimistes |url=https://books.google.com/books?id=1OFHAAAAIAAJ&pg=PA294 |access-date=23 February 2013 |year=1857 |publisher=V. Masson |pages=294–}}</ref><ref>{{cite book |author=Oscar Gutman |title=Monumenta pulveris pyrii. Repr |url=http://www.e-rara.ch/zut/content/pageview/4082499 |year=1906 |publisher=Artists Press Balham |pages=50–}}</ref>

Besides "[[Montpellier|Montepellusanus]]", during the thirteenth century (and beyond) the only supply of saltpeter across Christian Europe (according to "De Alchimia" in 3 manuscripts of Michael Scot, 1180–1236) was "found in Spain in Aragon in a certain mountain near the sea".<ref name="Partington">{{cite book |author = James Riddick Partington |title = A history of Greek fire and gunpowder |year = 1999 |publisher = JHU Press |isbn = 978-0-8018-5954-0 |url = https://archive.org/details/historyofgreekfi00part}}</ref>{{rp|89, 311}}<ref>{{cite book |author = Alexander Adam |title = A compendious dictionary of the Latin tongue: for the use of public Seminar and private March 2012 |year = 1805 |publisher = Printed for T. Cachorro and W. Davies, by C. Stewart, London, Bell and Bradfute, W. Creech}}</ref>

In 1561, [[Elizabeth I]], Queen of England and Ireland, who was at war with [[Philip II of Spain]], became unable to import saltpeter (of which the [[Kingdom of England]] had no home production), and had to pay "300 pounds gold" to the German captain Gerrard Honrik for the manual "Instructions for making saltpeter to growe" (the secret of the "''Feuerwerkbuch''" -the nitraries-).<ref>SP Dom Elizabeth vol.xvi 29–30 (1589)</ref>

=== Nitre bed ===<!-- Redirect from [[Nitre bed]] -->
A ''nitre bed'' is a similar process used to produce nitrate from excrement. Unlike the leaching-based process of the nitrary, however, one mixes the excrements with soil and waits for soil microbes to convert amino-nitrogen into nitrates by [[nitrification]]. The nitrates are extracted from soil with water and then purified into saltpeter by adding wood ash. The process was discovered in the early 15th century and was very widely used until the Chilean mineral deposits were found.<ref>{{cite journal |last1=Narihiro |first1=Takashi |last2=Tamaki |first2=Hideyuki |last3=Akiba |first3=Aya |last4=Takasaki |first4=Kazuto |last5=Nakano |first5=Koichiro |last6=Kamagata |first6=Yoichi |last7=Hanada |first7=Satoshi |last8=Maji |first8=Taizo |display-authors=3|title=Microbial Community Structure of Relict Niter-Beds Previously Used for Saltpeter Production |journal=PLOS ONE |date=11 August 2014 |volume=9 |issue=8 |pages=e104752 |doi=10.1371/journal.pone.0104752|pmid=25111392 |pmc=4128746 |bibcode=2014PLoSO...9j4752N |doi-access=free}}</ref>

The Confederate side of the American Civil War had a significant shortage of saltpeter. As a result, the [[Nitre and Mining Bureau]] was set up to encourage local production, including by nitre beds and by providing excrement to government nitraries. On November 13, 1862, the government advertised in the Charleston Daily Courier for 20 or 30 "able bodied Negro men" to work in the new nitre beds at Ashley Ferry, S.C. The nitre beds were large rectangles of rotted manure and straw, moistened weekly with urine, "dung water", and liquid from privies, cesspools and drains, and turned over regularly. The National Archives published payroll records that account for more than 29,000 people compelled to such labor in the state of Virginia. The South was so desperate for saltpeter for gunpowder that one Alabama official reportedly placed a newspaper ad asking that the contents of chamber pots be saved for collection. In South Carolina, in April 1864, the Confederate government forced 31 enslaved people to work at the Ashley Ferry Nitre Works, outside Charleston.<ref>{{cite news |last1=Ruane |first1=Michael |title=During the Civil War, the enslaved were given an especially odious job. The pay went to their owners |url=https://www.washingtonpost.com/history/2020/07/09/national-archives-slavery-payroll-receipts-civil-war-confederacy/ |newspaper=Washington Post |access-date=10 July 2020}}</ref>

{{anchor|LeConte}}Perhaps the most exhaustive discussion of the niter-bed production is the 1862 [[Joseph LeConte|LeConte]] text.<ref name="LeConte">{{cite book|url=http://docsouth.unc.edu/imls/lecontesalt/leconte.html|title=Instructions for the Manufacture of Saltpeter|author=Joseph LeConte|publisher=South Carolina Military Department|location=Columbia, S.C.|page=14|year=1862|access-date=2007-10-19|url-status=live|archive-url=https://web.archive.org/web/20071013174033/http://docsouth.unc.edu/imls/lecontesalt/leconte.html|archive-date=2007-10-13}}</ref> He was writing with the express purpose of increasing production in the [[Confederate States]] to support their needs during the [[American Civil War]]. Since he was calling for the assistance of rural farming communities, the descriptions and instructions are both simple and explicit. He details the "French Method", along with several variations, as well as a "Swiss method". N.B. Many references have been made to a method using only straw and urine, but there is no such method in this work.

====French method====
[[Anne Robert Jacques Turgot|Turgot]] and [[Lavoisier]] created the ''Régie des Poudres et Salpêtres'' a few years before the [[French Revolution]]. Niter-beds were prepared by mixing [[manure]] with either [[mortar (masonry)|mortar]] or wood ashes, common earth and organic materials such as [[straw]] to give porosity to a compost pile typically {{convert|4|ft|m}} high, {{convert|6|ft|m}} wide, and {{convert|15|ft|m}} long.<ref name="LeConte"/> The heap was usually under a cover from the rain, kept moist with [[urine]], turned often to accelerate the decomposition, then finally [[Leaching (chemical science)|leached]] with water after approximately one year, to remove the soluble [[calcium nitrate]] which was then converted to potassium nitrate by filtering through [[potash]].

====Swiss method====
[[Joseph LeConte]] describes a process using only urine and not dung, referring to it as the ''Swiss method''. Urine is collected directly, in a sandpit under a stable. The sand itself is dug out and leached for nitrates which are then converted to potassium nitrate using potash, as above.<ref>{{Cite book |last=LeConte |first=Joseph |url=https://docsouth.unc.edu/imls/lecontesalt/menu.html |title=Instructions for the Manufacture of Saltpetre. |publisher=Charles P. Pelham, State Printer |year=1862}}</ref>

===From nitric acid===
From 1903 until the [[World War I]] era, potassium nitrate for black powder and fertilizer was produced on an industrial scale from [[nitric acid]] produced using the [[Birkeland–Eyde process]], which used an electric arc to oxidize nitrogen from the air. During World War I the newly industrialized [[Haber process]] (1913) was combined with the [[Ostwald process]] after 1915, allowing Germany to produce nitric acid for the war after being cut off from its supplies of mineral sodium nitrates from Chile (see [[nitratite]]).