# Caustic soda

Caustic soda (sodium hydroxide) is the world's main industrial alkali, co-produced with chlorine and essential for alumina, pulp, soaps and chemicals.

Source page: https://www.materialinsights.org/chemicals/caustic_soda/

Commodity chemicals · Acids & alkalis · No. 6

- Single chemical
- Feedstock: Minerals and salts
- about 90 Mt a year (100% NaOH basis, 2025, indicative, derived from about 80 Mt chlorine x 1.13; no Euro Chlor or World Chlorine Council world total is published)
- 0.9 t CO₂e per t
- HS 281511, 281512
 Commodity chemicals · Acids & alkalis · Foundation · Matter

Caustic soda is chlorine's twin, so a PVC boom floods its market; US export prices roughly halved from 2022 to 2025.

Chart: Illustration: Caustic soda

##### Where it comes from

Chart: Map of where it comes from

Caustic soda is made by passing electricity through salt brine, with chlorine and a little hydrogen alongside; membrane cells give about 32% solution, then evaporated to 50%.

##### Three things to know

1. Every tonne of chlorine brings 1.13 t of caustic, so strong PVC demand floods the market with caustic and pushes its price down.
2. US Gulf export caustic fetched about $850/dmt in October 2022, but only $390-440/dmt three years later.
3. India's capacity rose from 4.4 Mt in FY2019 to 6.40 Mt in FY2024-25, turning it into a small net exporter.

##### The journey

1. 1 **Salt brine**About 1.5 t salt per tonne
2. 2 **Electrolysis**Membrane cells split brine, chlorine alongside
3. 3 **Evaporation**Concentrated to 50% liquid lye
4. 4 **Flakes**Dried to 98-99% solid for distance
5. 5 **End use**Alumina, pulp, soap and chemicals
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## Other sections

- [Overview](https://www.materialinsights.org/chemicals/caustic_soda/overview/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/caustic_soda/correlation/index.md)
- [Production route](https://www.materialinsights.org/chemicals/caustic_soda/routes/index.md)
- [Production](https://www.materialinsights.org/chemicals/caustic_soda/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/caustic_soda/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/caustic_soda/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/caustic_soda/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/caustic_soda/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/caustic_soda/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/chemicals/caustic_soda/characteristics/index.md)
- [Emissions](https://www.materialinsights.org/chemicals/caustic_soda/emissions/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/caustic_soda/links/index.md)