Which French chemist invented the Leblanc process for producing soda ash?

The French chemist who invented the Leblanc process for producing soda ash was Nicolas Leblanc.

Leblanc developed the process in the late 18th century to make sodium carbonate from common salt, meeting a major demand from glass, soap, textile, and paper manufacturers. His two-stage method first treated sodium chloride with sulfuric acid to produce sodium sulfate, then heated it with coal and limestone to form soda ash.

Leblanc patented the process in 1791 and established a plant at Saint-Denis that produced about 320 tons of soda ash annually. The French Revolution later confiscated the plant, and Leblanc never received the prize money promised for his work. Financial and personal difficulties followed, and he died in 1806.

The process helped launch large-scale chemical manufacturing but generated serious pollution, including hydrogen chloride and calcium sulfide waste. It was eventually replaced by the more efficient Solvay process, developed in the 1860s.