How is water glass made from soda ash and silica sand?

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Water glass, also known as sodium silicate, is manufactured by roasting a mixture of soda ash (sodium carbonate, ${Na}_{2} {CO}_{3}$ ) and silica sand (silicon dioxide, ${SiO}_{2}$ ) in a furnace.1

The process occurs at temperatures ranging from 1,000 to 1,400 °C (approximately 1,800 to 2,500 °F). During this reaction, the mixture releases carbon dioxide and produces sodium silicate ( ${Na}_{2} {SiO}_{3}$ ), which is represented by the following chemical equation:1

${Na}_{2} {CO}_{3} + {SiO}_{2} \to {Na}_{2} O \cdot {SiO}_{2} + {CO}_{2}$

This roasting process creates fused, glassy lumps known as cullet. These lumps can be sold in their solid form, ground into powders, or dissolved in hot water within pressurized reactors to create a syrupy liquid. The final product serves as a vital industrial source of sodium and is widely used in applications ranging from detergents and adhesives to water treatment processes.1