Solvay Process

Name:
Solvay Process
Detailed information:
(ammonia soda process). Manufacture of sodium carbonate (soda ash, Na₂CO₃) from salt, ammonia, carbon dioxide, and limestone by an ingenious sequence of reactions involving recovery and reuse of practically all the ammonia and part of the carbon dioxide. Limestone is heated to produce lime and carbon dioxide. The latter is dissolved in water containing the ammonia and salt, with resultant precipitation of sodium bicarbonate. This is separated by filtration, dried, and heated to form normal sodium carbonate. The liquor from the bicarbonate filtration is heated and treated with lime to regenerate the ammonia. Calcium chloride is a major by-product. Note: Because this process requires much energy and pollutes streams and rivers with chloride effluent, many plants using it have closed, production being obtained from the natural deposits in the western U.S.