ˈsä]lˌvā- also ˈsȯ] noun
Usage: usually capitalized S
Etymology: after Ernest Solvay died 1922 Belg. chemist, its inventor
: a process for making sodium carbonate from common salt and limestone that is based on the sparing solubility of sodium bicarbonate and involves burning the limestone to lime and carbon dioxide, passing the carbon dioxide into a strong brine saturated with ammonia to precipitate sodium bicarbonate and leave ammonium chloride in solution, and converting the bicarbonate to soda ash by calcining — called also ammonia soda process