Nicolas Leblanc was a French chemist who invented (1790) the Leblanc process for obtaining soda (sodium carbonate, Na₂CO₃) from common salt. The salt was treated with sulfuric acid to give sodium sulfate, which was then heated with chalk and charcoal to give a "black ash" from which the sodium carbonate could be washed with water. Leblanc was physician to Louis Phillipe, Duc d'Orléans, who helped him establish a factory to produce soda ash. The process was supplanted late in the 19th century by the Solvay process.