Solvay Process - Uses of Soda Ash

Uses of Soda Ash

Soda ash is used in many industrial processes, and its production is sometimes used as an indicator of economic health. The principal current uses include:

• Glass making: More than half the worldwide production of soda ash is used to make glass. Bottle and window glass (Soda-lime glass) is made by melting a mixture of sodium carbonate, calcium carbonate and silica sand (silicon dioxide (SiO₂)).
• Water treatment: Sodium carbonate is used to soften water (precipitates out Mg2+ and Ca2+ carbonates). This is used both industrially and domestically (in some washing powders).
• Making soaps and detergents: Often sodium carbonate is used as a cheaper alternative to lye (sodium hydroxide (NaOH)).
• Paper making: Sodium carbonate is used to make sodium bisulfite (NaHSO₃) for the "sulfite" method of separating lignin from cellulose.
• As a common alkali in many chemical factories because it is cheaper than NaOH and far safer to handle.
• Making sodium bicarbonate: NaHCO₃ is used in baking soda and fire extinguishers. Although NaHCO₃ is produced in the Solvay process, heating it to remove the ammonia it is contaminated with decomposes some NaHCO₃, so it is actually cheaper to react the finished Na₂CO₃ product with CO₂.
• Removing sulfur dioxide (SO₂) from flue gases in power stations. This is becoming more common, especially where stations have to meet stringent emission controls.