Solvay Process

The Solvay process is an industrial method for manufacturing sodium carbonate, also called soda ash, from ordinary salt brine and limestone, two cheap and widely available raw materials. The Belgian chemist Ernest Solvay began working on the problem in 1861 and, with his brother Alfred, built the first working plant at Couillet, Belgium by 1864; his key innovation was a 24-meter gas absorption tower in which carbon dioxide bubbled up through a descending flow of brine, paired with an efficient system for recovering and recycling ammonia. The Solvay process proved more economical and less polluting than the older Leblanc method it replaced, became commercially dominant by the 1890s, and Solvay-licensed plants still account for roughly three-quarters of the world's soda ash, a business estimated at 42 million tonnes a year in 2005.