Plant used for the manufacture of soda by the Solvay proces, early 1960s.
© Science Museum / Science & Society Picture Library
Model. Alkali, in the form of soda (sodium carbonate), has been used for centuries in manufacturing industries such as glas, textiles and soap. Until the end of the 18th century, soda was extracted from the ashes of either seaweed or the plant barilla. As these sources became scarce the price rose, so an alternative method of manufacture was sought. By the turn of the 20th century, the Solvay proces (based on reactions discovered by Fresnel in 1811) had replaced the previously used Leblanc proces. The Belgian Ernest Solvay overcame the problems which had rendered commercial application of Fresnel's discovery uneconomic by paying careful attention to the design of the plant.