Editing Solvay process (section)

== History ==
{{See also|alkali|potash|soda ash|Leblanc process|trona}}
The name "soda ash" is based on the principal historical method of obtaining alkali, which was by using water to extract it from the ashes of certain plants. Wood fires yielded potash and its predominant ingredient [[potassium carbonate]] (K<sub>2</sub>CO<sub>3</sub>), whereas the ashes from these special plants yielded "soda ash" and its predominant ingredient [[sodium carbonate]] (Na<sub>2</sub>CO<sub>3</sub>). The word "soda" (from the Middle Latin) originally referred to certain plants that grow in salt solubles; it was discovered that the ashes of these plants yielded the useful alkali soda ash. The cultivation of such plants reached a particularly high state of development in the 18th century in Spain, where the plants are named ''barrilla'' (or "[[barilla]]" in English).<ref>The barilla used for soda ash production refers to any of several bushy plants that are well adapted to grow in salt marshes, and that are common in Spain and Italy. The ashes of these plants can contain as much as 30% sodium carbonate. The principal species for soda ash production were the "[[saltwort]]s" ''[[Salsola soda]]'' or ''[[Salsola kali]]'', but several other species could also be used.</ref><ref>Pérez, Joaquín Fernández (1998). [https://web.archive.org/web/20071218070149/http://www.ucm.es/info/antilia/revista/vol4-en/ant4-1-en.htm "From the barrilla to the Solvay factory in Torrelavega: The Manufacture of Saltwort in Spain,"] ''Antilia: The Spanish Journal of History of Natural Sciences and Technology,'' Vol. IV, Art. 1. ISSN 1136-2049. Archived by WebCite from [http://www.ucm.es/info/antilia/revista/vol4-en/ant4-1-en.htm this original URL] on 2008-03-01.</ref><ref>Grieve, M. (1931). ''A Modern Herbal,'' {{ISBN|0-486-22798-7}} & 0486227995. See section on [http://www.botanical.com/botanical/mgmh/g/glassw18.html glasswort]. Retrieved October 21, 2005.</ref> The ashes of [[kelp]] also yield soda ash and were the basis of an enormous 18th-century industry in Scotland.<ref>{{cite journal |title=The Scottish kelp industry and its archaeology |last=Hothersall |first=Susan |date=2012 |journal=Historic Argyll |pages=32–36 |url=http://www.lahsoc.org.uk/journals/journal_2012/6%20Kelp%20industry.pdf}}</ref> Alkali was also mined from dry lakebeds in Egypt.

By the late 18th century these sources were insufficient to meet Europe's burgeoning demand for alkali for soap, textile, and glass industries.<ref name=Kiefer1>{{cite journal|author=Kiefer, David M. |url=http://pubs.acs.org/subscribe/journals/tcaw/11/i01/html/01chemchron.html |title=It was all about alkali |journal=Today's Chemist at Work |volume=11 |issue=1 |pages=45–6 |url-status=unfit |archive-url=https://web.archive.org/web/20021107104036/http://pubs.acs.org/subscribe/journals/tcaw/11/i01/html/01chemchron.html |archive-date=November 7, 2002 }} Online version archived at WebCite from [http://pubs.acs.org/subscribe/journals/tcaw/11/i01/html/01chemchron.html this original URL] on 2008-03-12.</ref> In 1791, the French physician [[Nicolas Leblanc]] developed a method to manufacture soda ash using salt, [[limestone]], [[sulfuric acid]], and [[coal]]. Although the [[Leblanc process]] came to dominate alkali production in the early 19th century, the expense of its inputs and its polluting byproducts (including [[hydrogen chloride]] gas) made it apparent that it was far from an ideal solution.<ref name="Kiefer1" /><ref name="Kiefer" />

It has been reported that in 1811 French physicist [[Augustin Jean Fresnel]] discovered that sodium bicarbonate precipitates when carbon dioxide is bubbled through ammonia-containing brines – which is the chemical reaction central to the Solvay process. The discovery wasn't published. As has been noted by Desmond Reilly, "The story of the evolution of the ammonium–soda process is an interesting example of the way in which a discovery can be made and then laid aside and not applied for a considerable time afterwards."<ref>{{cite journal | author = Reilly, Desmond |date=December 1951 | title = Salts, Acids & Alkalis in the 19th Century. A Comparison between Advances in France, England & Germany | journal = Isis | volume = 42 | issue = 4 | pages = 287–296 | doi = 10.1086/349348 | jstor=226807 | pmid=14888349|s2cid=8272431 }}</ref> Serious consideration of this reaction as the basis of an industrial process dates from the British patent issued in 1834 to H. G. Dyar and J. Hemming. There were several attempts to reduce this reaction to industrial practice, with varying success.

In 1861, [[Belgium|Belgian]] industrial chemist [[Ernest Solvay]] turned his attention to the problem; he was apparently largely unaware of the extensive earlier work.<ref name="Kiefer" /> His solution was a {{convert|24|m|ft|abbr=on}} gas absorption tower in which carbon dioxide bubbled up through a descending flow of brine. This, together with efficient recovery and recycling of the ammonia, proved effective. By 1864 Solvay and his brother Alfred had acquired financial backing and constructed a plant in [[Couillet, Belgium|Couillet]], today a suburb of the Belgian town of [[Charleroi]]. The new process proved more economical and less polluting than the Leblanc method, and its use spread. In 1874, the Solvays expanded their facilities with a new, larger plant at [[Nancy, France|Nancy]], France.

In the same year, [[Ludwig Mond]] visited Solvay in Belgium and acquired rights to use the new technology. He and [[John Tomlinson Brunner|John Brunner]] formed the firm of [[Brunner Mond|Brunner, Mond & Co.]], and built a Solvay plant at [[Winnington]], near [[Northwich]], [[Cheshire]], England. The facility began operating in 1874. Mond was instrumental in making the Solvay process a commercial success. He made several refinements between 1873 and 1880 that removed byproducts that could slow or halt the process.

In 1884, the Solvay brothers licensed Americans William B. Cogswell and Rowland Hazard to produce soda ash in the US, and formed a joint venture ([[Solvay Process Company]]) to build and operate a plant in [[Solvay, New York]].

[[File:SolvayPlant-NY-ErieCanal.jpg|thumb|right|Solvay Process Plant in [[Solvay, New York]]; the [[Erie Canal]] passed through this plant until about 1917. From the Solvay Process collection of the Solvay, New York, Public Library.]]

By the 1890s, Solvay-process plants produced the majority of the world's soda ash.

In 1938 large deposits of the mineral [[trona]] were discovered near the [[Green River (Colorado River tributary)|Green River]] in [[Wyoming]] from which sodium carbonate can be extracted more cheaply than produced by the process. The original Solvay New York plant closed in 1986, replaced in the US by a factory in Green River. Throughout the rest of the world, the Solvay process remains the major source of soda ash.