Editing Potassium nitrate (section)

===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.