or ammonia-soda process
Modern method of manufacturing sodium carbonate (soda ash), devised and commercialized in Belgium by Ernest Solvay (1838–1922).
Common salt (sodium chloride) is treated with ammonia and then carbon dioxide, under carefully controlled conditions, to form sodium bicarbonate and ammonium chloride. When heated, the bicarbonate yields sodium carbonate, the desired product; the ammonium chloride is treated with lime to produce ammonia (for reuse) and calcium chloride. The process proved of great commercial value, since large quantities of soda ash are used in making glass, detergents, and cleansers. See also caustic soda .