Why Sodium Carbonate Is Used in Glass

Window Glass Is Often Made with Sodium Carbonate

Sodium carbonate acts as a flux (fusion agent) in the production of common glass, also known as soda lime glass. Other ingredients in glass include sand and limestone, with elements such as iron added for coloring.

Process

Soda lime glass is created when an alkali (sodium carbonate), limestone, and sand are combined, heated, and then cooled down very rapidly.

Function

Sand usually starts to soften at 2,000 degrees C. The reaction with sodium carbonate brings this temperature down to 1,000 degrees C, which is more manageable. Typical glass contains 12-18 percent sodium carbonate.

Properties

Soda lime glass is the most common and least expensive glass. This glass will not contaminate its contents, is easy to clean, and blocks some ultraviolet light.

Uses

Soda lime glass is usually smooth and highly transparent, making it suitable for windows and containers.

Warning

Soda lime glass can break when subjected to sudden hot temperatures. It starts to weaken upon production; it may be coated or tempered for additional strength.

References

• Lenntech: Making Soda Lime Glass
• Ceramics.org: Soda Lime Glass Issues
• Probert Encyclopedia: Sodum Carbonate as Flux