Sodium silicate

Water glass: sand fused with soda ash, the cheap silica source behind precipitated silica for tyres, detergents, zeolites and binders.

Commodity chemicals · Other inorganics · No. 11

• Single chemical
• Feedstock: Minerals and salts
• capacity about 6 Mt a year (indicative, basis: Europe 1.2 Mt, with Europe and North America about one-third and Asia about 60% of world capacity); output about 5 Mt (indicative, at about 85% utilisation)
• 0.8 t CO₂e per t
• HS 283911

Melt quartz sand with soda ash and you get water glass, the hidden ingredient behind fuel-saving green tyres.

Chart: Illustration: Sodium silicate

Where it comes from

Chart: Map of where it comes from

Quartz sand and soda ash are melted at about 1,300-1,500 C into a glass, or sand is dissolved directly in hot caustic soda under pressure.

Three things to know

1. About 40% of European silicate use goes into precipitated silica for low-rolling-resistance tyres that cut fuel use.
2. Each tonne of ratio-3.3 glass needs about 0.40 t of soda ash, which releases about 0.17 t of CO₂ before any fuel burns.
3. Asia holds about 60% of the roughly 6 Mt of world capacity, while Europe has about 1.2 Mt.

The journey

1. 1 Sand and sodaLow-iron quartz sand plus soda ash
2. 2 FurnaceMelted at 1,300-1,500 C into glass
3. 3 Glass lumpsCooled, sold solid or dissolved
4. 4 DissolvingSteamed in autoclaves to thick solutions
5. 5 ConversionSilica for tyres, zeolites, detergents, binders

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