Caustic Soda (Sodium Hydroxide)
The heavy-duty alkali behind pulp, paper, soap and alumina refining — one of the highest-volume industrial chemicals in the world.
Chelora Chemicals supplies pellet, flake and 50% liquid caustic soda to industrial producers worldwide, with full documentation on every consignment.
Product identity
- CAS Number
- 1310-73-2
- IUPAC name
- Sodium hydroxide
- Molecular formula
- NaOH
- Molecular weight
- 40.00 g/mol
- Melting point
- 318 °C
- Boiling point
- 1,388 °C
- UN Number
- UN 1823 / UN 1824
- HS Code
- 2815.11 / 2815.12
Note: Dissolving solid caustic soda in water is strongly exothermic. Confirm requirements with your regulatory affairs team.
What Caustic Soda is used for
Caustic Soda (Sodium Hydroxide) is a white, highly water-soluble, corrosive solid supplied as pellets, flakes or beads, or as a 50% liquid solution. It is produced via the chlor-alkali process, the electrolysis of brine, and is one of the highest-tonnage industrial chemicals manufactured globally.
Its largest uses are in pulp and paper production (the kraft pulping process), soap and detergent manufacture, and alumina refining via the Bayer process, where it digests bauxite ore to extract alumina. It is also central to textile mercerising of cotton, water treatment pH correction, and as a general-purpose alkali across the chemical manufacturing industry, including biodiesel production.
Where it sits in the value chain
- Brine (saturated NaCl solution) the feedstock, electrolysed in the chlor-alkali process.
- Caustic Soda (this product) co-produced with chlorine and hydrogen, supplied to the concentration or form your process requires.
- Pulp / soap / alumina / treated water the downstream outcomes built on this alkali.
Handling character
Caustic Soda is highly corrosive and causes severe skin burns and eye damage, and dissolving the solid in water releases significant heat. Full hazard detail is in the Safety section below.
| Parameter | Typical value |
|---|---|
| Appearance (solid) | White pellets, flakes or beads |
| NaOH assay (solid) | 98.0% - 99.5% min |
| NaOH assay (liquid) | ~50% w/w |
| Sodium carbonate | < 1.5% (typical) |
Important: the figures above are indicative of commercial material and are offered for planning only. The batch certificate of analysis is the governing document.
| Property | Value |
|---|---|
| Physical state | White, deliquescent solid or clear liquid |
| Melting point | 318 °C |
| Boiling point | 1,388 °C |
| Density (solid) | 2.13 g/cm³ |
| Water solubility | Very high, exothermic dissolution |
| pH (1% solution) | ~13 |
Physical constants compiled from public reference data for CAS 1310-73-2 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put Caustic Soda to work
From kraft pulp mills to soap plants and alumina refineries.
Pulp & paper (kraft process)
Used with sodium sulfide to delignify wood chips and produce kraft pulp for paper and board.
- Technical-grade specification
- Bulk liquid supply available
Soap & detergent manufacture
Reacted with fats and oils (saponification) to produce soap, and used as a builder in detergent formulations.
- Consistent assay batch to batch
- Documented batch traceability
Alumina refining (Bayer process)
Digests bauxite ore at high temperature and pressure to extract alumina for aluminium smelting.
- High-purity grade available
- Full analytical documentation available
Textile mercerising
Used to treat cotton fibres and fabrics, improving strength, lustre and dye uptake.
- Low-iron, low-chloride grades available
- Technical desk review on request
Water & chemical treatment
Used for pH correction, water treatment, and as a general alkali in chemical manufacturing and biodiesel production.
- Industrial-grade material
- Full documentation supplied
Contract & scheduled supply
Industrial plants running continuous consumption are supported with scheduled bulk delivery.
- Annual contracts with scheduled call-off
- Second source held in reserve
How we supply Caustic Soda
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. Caustic soda's corrosivity and heat of dissolution make form, packaging and transport approval critical — that shapes how we manage this line.
We place your order with whichever qualified producer best matches your required form and grade, your price point and your delivery window, and confirm your jurisdiction's import requirements before booking.
We keep a second qualified source on this line, so a single-plant disruption never becomes your production problem.
- Assay and impurity profile confirmed before we quote. Consistency matters to pulp, soap and alumina processes.
- UN 1823 / UN 1824 documentation managed end to end. Classification, labelling and carrier compliance confirmed before booking.
- Temperature-managed logistics for liquid caustic. 50% solution can crystallise below ~12 °C, so we confirm heat-traced transport where needed.
- Batch traceability to the producing plant. Full chain of custody documentation on request.
- Export machinery handled in-house. Classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
- Technical-grade material sourced to your process. Matched precisely to your pulp, soap, textile or chemical specification.
Packed the way your plant receives it
Bag, drum or bulk tank — tell us your preferred format and we will quote and classify to it.
25-50 kg moisture-sealed bags
Multi-wall bags with poly liner, protecting against the pellets' hygroscopic nature.
1,000 kg bulk bags
Sealed jumbo bags for bulk solid caustic orders.
50% liquid, heat-traced where required
ISO tank or road tanker shipment of 50% liquid caustic, insulated or heat-traced in cold climates.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with documentation filed before booking.
~1,000 litre totes
Lined IBC totes for mid-volume liquid caustic orders.
Contracted call-off supply
We hold contracted tonnage and release it against your consumption calendar.
Highly corrosive — handle accordingly
Caustic Soda is highly corrosive and causes severe, often deep, skin burns and eye damage, and dissolution in water generates significant heat. The summary below is orientation only — the safety data sheet supplied with your specific batch is the authoritative document.
Classified hazards
H314Causes severe skin burns and eye damage.H290May be corrosive to metals.
Always add caustic to water, never water to caustic, when dissolving. Always read the SDS issued with your specific batch.
Storage
Store in tightly closed, corrosion-resistant containers in a dry area, protected from moisture (solid grades are hygroscopic) and away from acids and reactive metals such as aluminium and zinc.
Handling
Use chemical-resistant gloves, goggles or face shield, and protective clothing. Dissolve slowly with controlled cooling, as the process is strongly exothermic.
Transport
Shipped as UN 1823 (Sodium hydroxide, solid) or UN 1824 (Sodium hydroxide solution), both corrosive. We confirm and document exact classification for your specific form, shipment and destination.
Every batch, documented
We verify documentation before dispatch so there are no surprises at your incoming-goods bench.
Specification agreed
NaOH assay, form and impurity limits confirmed against your process requirement before order placement.
Producer batch testing
The producing plant tests each batch against the agreed specification before release.
Documentation review
COA, SDS and transport paperwork checked by our desk before the shipment is booked.
Traceable dispatch
Each shipment is traceable to its producing batch, with full chain-of-custody records on request.
How Caustic Soda is made
Caustic Soda is produced by the chlor-alkali process — the electrolysis of saturated sodium chloride (brine) solution, typically in modern membrane cell plants. The process simultaneously generates chlorine gas at the anode and hydrogen and sodium hydroxide at the cathode, making all three products commercially linked.
We do not publish operating process parameters here; this is background only. Full technical documentation accompanies every shipment, and any process-specific detail you need is best confirmed directly with our technical desk.
| Chemical family | Strong inorganic base (alkali metal hydroxide) |
|---|---|
| Dissociation | Fully dissociates in water (strong base) |
| Reactivity | Reacts exothermically with acids, water and amphoteric metals (Al, Zn) |
| Co-products | Chlorine, Hydrogen (from the same chlor-alkali process) |
Explore the wider acids & alkalis range
Caustic Soda, answered
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