Editing Leblanc process (section)

== Industrial history ==

Leblanc established the first Leblanc process plant in 1791 in [[Saint-Denis, Seine-Saint-Denis|St. Denis]].  However, [[French Revolution]]aries seized the plant, along with the rest of Louis Philip's estate, in 1794, and publicized Leblanc's [[trade secret]]s. [[Napoleon I]] returned the plant to Leblanc in 1801, but lacking the funds to repair it and compete against other soda works that had been established in the meantime, Leblanc committed [[suicide]] in 1806.<ref name="Aftalion14"/>

By the early 19th century, French soda ash producers were making 10,000 - 15,000 tons annually.  However, it was in Britain that the Leblanc process became most widely practiced.<ref name='Aftalion14'>{{Cite book | first = Fred | last = Aftalion | title = A History of the International Chemical Industry | location = Philadelphia | publisher = University of Pennsylvania Press | year = 1991 | pages = 14–16 | isbn = 978-0-8122-1297-6}}</ref>   The first British soda works using the Leblanc process was built by [[William Losh|the Losh family of iron founders]] at the [[Losh, Wilson and Bell]] works in Walker on the [[River Tyne]] in 1816, but steep British [[tariff]]s on salt production hindered the economics of the Leblanc process and kept such operations on a small scale until 1824.  Following the repeal of the salt tariff, the British soda industry grew dramatically. The [[Bonnington Chemical Works]] was possibly the earliest production,<ref>{{Cite journal|last=Ronalds|first=B.F.|date=2019|title=Bonnington Chemical Works (1822-1878): Pioneer Coal Tar Company|journal=International Journal for the History of Engineering & Technology|volume=89|issue=1–2|pages=73–91|doi=10.1080/17581206.2020.1787807|s2cid=221115202}}</ref> and the chemical works established by [[James Muspratt]] in [[Liverpool]] and [[Flint, Flintshire|Flint]], and by [[Charles Tennant]] near [[Glasgow]] became some of the largest in the world.  Muspratt's Liverpool works enjoyed proximity and transport links to the Cheshire salt mines, the St Helens coalfields and the North Wales and Derbyshire limestone quarries.<ref>Peter Reed, Acid Rain and the Rise of the Environmental Chemist in Nineteenth Century Britain, (2014), p. 94</ref> By 1852, annual soda production had reached 140,000 tons in Britain and 45,000 tons in France.<ref name="Aftalion14"/>  By the 1870s, the British soda output of 200,000 tons annually exceeded that of all other nations in the world combined.{{Citation needed|date=January 2021}}

=== Obsolescence ===
In 1861, the [[Belgium|Belgian]] chemist [[Ernest Solvay]] developed a more direct process for producing soda ash from salt and limestone through the use of [[ammonia]].  The only waste product of this [[Solvay process]] was [[calcium chloride]], and so it was both more economical and less polluting than the Leblanc method.  From the late 1870s, Solvay-based soda works on the [[Europe]]an continent provided stiff competition in their home markets to the Leblanc-based British soda industry. Additionally the [[Brunner Mond]] Solvay plant which opened in 1874 at [[Winnington]] near [[Northwich]] provided fierce competition nationally. Leblanc producers were unable to compete with Solvay soda ash, and their soda ash production was effectively an adjunct to their still profitable production of chlorine, bleaching powder etc. (The unwanted by-products had become the profitable products).  The development of electrolytic methods of [[chlorine]] production removed that source of profits as well, and there followed a decline moderated only by "gentlemen's' agreements" with Solvay producers.<ref>Reader W J ''Imperial Chemical Industries; A History Volume 1 The Forerunners 1870-1926'' Oxford University Press 1970 SBN 19 215937 2</ref> By 1900, 90% of the world's soda production was through the Solvay method, or on the North American continent, through the mining of [[trona]], discovered in 1938, which caused the closure of the last North American Solvay plant in 1986.

The last Leblanc-based soda ash plant in the West closed in the early 1920s,<ref name="Kiefer" /> but when during WWII Nationalist China had to evacuate its industry to the inland rural areas, the difficulties in importing and maintaining complex equipment forced them to temporarily re-establish the Leblanc process.<ref>{{Cite book |last=Reardon-Anderson |first=James |url=https://books.google.com/books?id=o_XxL0f-AWMC&q=Leblanc |title=The Study of Change: Chemistry in China, 1840-1949 |date=1991 |publisher=Cambridge University Press |isbn=978-0-521-53325-6 |language=en}}</ref>

However, the Solvay process does not work for the manufacture of [[potassium carbonate]], because it relies on the low solubility of the corresponding [[bicarbonate]].