Sodium Hydroxide (Caustic Soda)
NaOH
Sodium hydroxide (caustic soda) is a strong alkali (NaOH, CAS 1310-73-2) supplied as a clear aqueous solution at 30-50% concentration. It is used for pH adjustment, precipitation of heavy metals such as zinc and copper, and neutralization of acidic wastewater, alongside roles in paper, textile and soap production. CHIMI ART supplies caustic soda solution across Egypt in drums, IBCs and bulk flexitanks, with a certificate of analysis per batch.
Product Overview
Sodium hydroxide (caustic soda) is a strong alkali (NaOH, CAS 1310-73-2) supplied as a clear aqueous solution at 30-50% concentration. It is used for pH adjustment, precipitation of heavy metals such as zinc and copper, and neutralization of acidic wastewater, alongside roles in paper, textile and soap production. CHIMI ART supplies caustic soda solution across Egypt in drums, IBCs and bulk flexitanks, with a certificate of analysis per batch.
Technical Specifications
- Chemical Formula
- NaOH
- CAS Number
- 1310-73-2
- Appearance
- Clear colorless liquid
- Concentration
- 30-50% NaOH
- Specific Gravity
- 1.33-1.52
- pH Range
- 14.0 (1% solution)
- Solubility
- Fully miscible with water
- Available Packaging
- 200L drums · 1000L IBC · Bulk flexitank
- Shelf Life
- 12 months
- Storage Conditions
- Stainless steel containers
| Property | Value |
|---|---|
| Chemical Formula | NaOH |
| CAS Number | 1310-73-2 |
| Appearance | Clear colorless liquid |
| Concentration | 30-50% NaOH |
| Specific Gravity | 1.33-1.52 |
| pH Range | 14.0 (1% solution) |
| Solubility | Fully miscible with water |
| Available Packaging | 200L drums · 1000L IBC · Bulk flexitank |
| Shelf Life | 12 months |
| Storage Conditions | Stainless steel containers |
Applications
Dosing Guidelines
Caustic soda is dosed by metering pump directly from the supplied 30-50% solution, or after dilution for finer control on small streams; dilution releases substantial heat, so always add caustic to water slowly with mixing. For pH adjustment and neutralization the required dose follows the acidity of the stream — establish it by laboratory titration, then control in the plant with a pH feedback loop, taking advantage of caustic's fast response. For heavy-metal precipitation, the operating pH is selected for the metals present and confirmed by bench or jar testing before full-scale dosing. Verify with a plant trial before standardizing any dose.
How It Works
Sodium hydroxide dissociates completely in water into sodium and hydroxide ions, making it one of the fastest-acting alkalis for pH correction. The hydroxide ions neutralize free acidity directly, forming water and a soluble sodium salt, which is why caustic dosing gives a quick, predictable pH response well suited to automated control loops. In heavy-metal removal, raising the pH converts dissolved metals such as zinc and copper into sparingly soluble metal hydroxides that precipitate and are removed by settling or filtration; each metal has a pH region of minimum solubility, so the operating pH is chosen for the metals present and confirmed by bench testing. The same alkalinity drives saponification and cleaning chemistry in the paper, textile and soap industries.
Usage Tips
Store caustic soda solution in stainless steel or HDPE tanks; shelf life is 12 months. Never use aluminum, zinc, tin or galvanized fittings — caustic attacks them and generates flammable hydrogen gas. Note that 50% solution begins to crystallize at cool ambient temperatures (typically around 12-15 °C), so outdoor tanks and lines may need heat tracing, or a switch to 30% strength in winter. Dilution is strongly exothermic: add caustic to water slowly with mixing. Wear alkali-resistant gloves, goggles and face protection — caustic causes severe burns, particularly to the eyes.
Certifications & Compliance
Frequently Asked Questions
What is caustic soda used for in wastewater treatment?
Caustic soda raises pH quickly and predictably, which makes it the standard alkali for neutralizing acidic effluent and for automated pH-control loops. Raising the pH also precipitates dissolved heavy metals such as zinc and copper as insoluble hydroxides, which are then removed by settling or filtration ahead of discharge.
Should I buy 30% or 50% caustic soda solution?
50% delivers more alkali per liter, reducing freight and storage volume, but it begins to crystallize at cool ambient temperatures (typically around 12-15 °C), so outdoor tanks and lines may need heat tracing. 30% stays liquid at lower temperatures and is easier to meter on small systems. Choose by climate, storage arrangements and dosing precision.
At what pH do heavy metals precipitate with caustic soda?
Each metal hydroxide has its own region of minimum solubility — there is no single pH that suits every metal, and overshooting can redissolve amphoteric metals such as zinc. Establish the operating pH by bench or jar testing on the actual effluent for the metal mix present, then hold it with feedback pH control.
Which materials must never contact caustic soda?
Aluminum, zinc, tin and galvanized steel are attacked by caustic soda with evolution of flammable hydrogen gas, so they must be excluded from tanks, fittings and fasteners. Store the solution in stainless steel or HDPE, as recommended for this product, and use compatible elastomers for seals and hoses.
What pack sizes is caustic soda supplied in?
CHIMI ART supplies caustic soda solution in 200 L drums, 1,000 L IBCs and bulk flexitanks, with a certificate of analysis per batch. TDS and SDS documents are available for each product; contact the sales team for volume pricing and delivery scheduling across Egypt.
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