Solvay process [for Ernest Solvay Solvay, Ernest (ĕrnĕst` sôlvā`), 1838–1922, Belgian industrial chemist and philanthropist.
..... Click the link for more information. ], commercial process for the manufacture of sodium carbonate (washing soda). Ammonia and carbon dioxide are passed into a saturated sodium chloride solution to form soluble ammonium hydrogen carbonate, which reacts with the sodium chloride to form soluble ammonium chloride and a precipitate of sodium hydrogen carbonate (sodium bicarbonate) if the temperature is maintained below 15°C;. The sodium hydrogen carbonate is filtered off and heated to produce sodium carbonate.

Solvay process

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.