What is 32% NaOH? This is a sodium hydroxide solution (liquid caustic soda) with a concentration of approximately 32% by weight (w/w) — a strong, clear alkali that is easier to pump and meter than caustic soda flakes in many plant processes.
sodium hydroxideCAS 1310-73-2Used for pH adjustment, acid neutralization, industrial cleaning, pulp and paper, textiles, and many chemical processes. B2B goods usually include a COA/MSDS per batch when quoted.
- 32% NaOH = liquid caustic soda ~32% w/w; very high pH, corrosive to skin/eyes and some metals (aluminum, zinc...).
- Convenient for tanks/cans: easier to measure than solid caustic soda; dilution releases a lot of heat — always add caustic soda to water, not the other way around.
- Compared to 45–50%: 32% is more dilute, with a higher freezing point — choose concentration according to process and storage.
Purchasing and engineering teams often ask the same questions at the same time: 32% liquid caustic soda What is it, what are its specifications, which industries is it used in, how does it differ from 45-50%, and what PPE/protective materials are needed? This article provides a practical summary for you to compare with the COA and communicate with suppliers — it does not replace internal SOPs or shipment MSDS.
What is 32% NaOH (liquid caustic soda)?
Sodium hydroxide (NaOH) is a strong inorganic base. It is commercially available. Solid scales/grains or fluid various concentrations. 32% NaOH (32% lye, caustic soda liquid, lye) is an aqueous solution with a nominal concentration of approximately 32% ± COA tolerance (w/w).
Compared to caustic soda flakes, the 32% formulation reduces the dissolution step at the point of use, is easier to pump, and allows for continuous dose control on the production line. Disadvantages: larger transport volume (water makes up the remainder) and it may solidify/freeze at low temperatures — requiring climate-controlled storage planning.
- Formula: NaOH · molar mass ~40,00 g/mol
- Trade names: sodium hydroxide, caustic soda
- CAS: 1310-73-2 (Matching MSDS/COA; remains unchanged regardless of solution percentage)
Technical specifications for 32% NaOH
The table below is Common technical references Add liquid caustic soda at approximately 32%. Acceptance values are taken from the COA of each batch.
| Targets | Reference value (NaOH ~32%) |
|---|---|
| Main ingredient | Sodium hydroxide (NaOH) in water |
| Concentration | ~32% w/w (± COA tolerance, typically ~±1%) |
| CAS | 1310-73-2 |
| Condition / Appearance | A clear, colorless to slightly cloudy liquid; slightly more viscous than water. |
| Density (~20°C) | Approximately 1,34–1,35 g/cm³ (based on COA/measured temperature) |
| pH | Very alkaline (range ~13–14 depending on sample dilution) |
| Freezing point (approximate) | Around +5°C to +9°C — 45–50% more likely to solidify/freeze in cold storage. |
| Dilution | Dissolves in water; releases heat strongly. |
| Common packaging | HDPE cans, IBCs, tank trucks (according to supplier and delivery route) |
| B2B Profile | COA per batch; MSDS; packaging specifications and delivery conditions |
Upon receiving the goods: check the seal, concentration label, lot number, and compare the COA with the order. Any unusual cloudiness, foreign matter, or strange phenomena — isolate the product and consult a technician before filling the production tanks.
Chemical properties to remember
- Neutralize acids: Strong reaction, heat generation — control the injection rate.
- CO absorption2: Leaving a container open for too long can cause sodium carbonate to form; keep the lid tightly closed.
- Corrosion of the skin, eyes, and mucous membranes: Chemical burns; PPE required.
- Material: It corrodes aluminum, zinc, tin, etc. Suitable steel is preferred, HDPE/PP for packaging. Do not store industrial concentrations in ordinary glass bottles.
- Lipid-protein decontamination / saponification: Industrial cleaning and equipment cleaning platform.
Dilution: Add caustic soda slowly to the water. (Preferably cold water/stirring). Do not pour water into concentrated caustic soda — risk of localized boiling and splashing. Your factory's SOP may be more detailed (pump, temperature sensor, safety valve).
Common industrial applications
- Water/Wastewater Treatment: pH adjustment, acid neutralization, and coagulation/precipitation support in certain systems — dosage according to jar-test.
- Paper and pulp: The steps for alkali/Krafting vary depending on the factory's technology.
- Dyeing and weaving: Mercerize, bleach, fiber preparation — control of temperature and concentration.
- Chemicals, soap, detergent: Alkaline source, neutralizing, pH adjusting semi-finished product.
- Metal / surface: Degrease before painting or plating (for compatible materials); avoid aluminum unless a protective process is required.
- Specific grades (oil and gas, food, etc.): Only if the grade and legal documentation are correct — not all industrial lots are food grade by default.
Choose 32% when the process and pump are optimized at this concentration, or the storage facility cannot tolerate a more concentrated solution. Less water per kg of pure NaOH is needed, or a lower freezing point is required — consider 45–50% (same CAS, different percentages and storage operation).
32% NaOH compared to 45% and 50%
| Criteria | NaOH ~32% | NaOH ~45–50% |
|---|---|---|
| w/w concentration | Up to 32% | ~45% or ~50% |
| Pure NaOH / volume (general) | Lower | Higher — less water per unit of alkalinity |
| Pumping/Dosing | Easy, common cans – IBCs – tanks | Easy but thicker/viscous; equipment must be suitable. |
| Freezing point (approximate) | Taller (freezes easily in cold weather) | Typically less than 32% — inventory planning is still needed. |
| CAS | 1310-73-2 | 1310-73-2 |
| When should it be prioritized? | Ready-made process 32%; medium cold storage | Needs to be thicker or 50% of the factory standard catalog. |
For the same volume of solution, the amount of pure NaOH varies — recalculate based on % COA before adding on a large scale. If ~50% is needed, refer to: 50% liquid NaOH.
Safety, PPE, and storage
32% NaOH remains a highly corrosive alkali: it can cause skin burns, eye damage, respiratory irritation when misted, and heat release when mixed with acids or diluted incorrectly.
Minimum PPE (according to lot MSDS and plant risk assessment): Chemical safety glasses + face shield in case of splash risk; alkali-resistant gloves; apron/chemical protective clothing; closed-toe shoes; ventilation/suitable mask if foggy or in enclosed spaces.
General first aid instructions (do not replace MSDS/medical records): Skin — rinse under running water for several minutes, remove clothing contaminated with the chemical; eyes — rinse continuously, do not “neutralize” with acid at the site, seek ophthalmic emergency care; inhalation — move to a well-ventilated area; ingestion — do not induce vomiting, call emergency services as directed by medical professionals.
Preservation: Compatible containers/tanks (HDPE/PP or tanks designed for alkalis), tightly sealed, resistant to acids and corrosive metals, clearly labeled, and with spill-proof trays. Cold storage: note freezing point ~32%. Spills must be handled by trained personnel; do not discharge sewers until environmental regulations are met.
Do you need industrial-grade liquid caustic soda (NaOH) with a Certificate of Analysis/Ms. Data Sheet (COA)?
Loc Thien provides consultation on concentration and B2B pricing based on your needs, packaging, and delivery area. See our NaOH (caustic soda) catalog: hoachatlocthien.com/danh-muc/hoa-chat/xut-naohIf the process requires approximately 50%: 50% liquid NaOH.
Technical/Purchasing Hotline: (+84) 979 891 929.
Top Q&A
What is 32% NaOH?
Sodium hydroxide solution (liquid caustic soda) approximately 32% w/wOther names: 32% liquid caustic soda, 32% caustic soda. CAS 1310-73-2.
What is the CAS value of caustic soda/NaOH?
CAS 1310-73-2 (sodium hydroxide). When comparing MSDS/COA, match CAS and concentration/form (liquid 32/45/50% or flakes) with order — CAS remains constant according to solution percentage.
How does 32% NaOH differ from 45% and 50%?
With the same NaOH concentration but different percentages: 32% is more dilute, contains more water per kg of pure alkali, and usually has a higher freezing point. 45–50% is more concentrated, and the alkali is more effective if the equipment/storage is suitable. Choose according to the process — do not change the concentration subjectively.
What is the approximate density of 32% NaOH?
Usually around 1,34–1,35 g/cm³ at ~20°C (For reference only). Acceptance testing is based on the COA and the batch's measurement conditions.
How to safely dilute 32% caustic soda?
Add caustic soda slowly to the water. (Preferably cold water/stirring). Do not add water to concentrated caustic soda. Use PPE, ensure good ventilation, and follow SOP/MSDS — the reaction is highly exothermic.
What is 32% NaOH used for?
pH adjustment/neutralization of wastewater, industrial cleaning, pulp and paper, textiles, chemical detergent, surface cleaning (compatible materials), and some specific grade applications. Dose and grade according to process + COA.
What precautions should be taken when storing 32% liquid caustic soda?
Compatible packaging, tight-fitting lid, protection against acids and corrosive metals, clear labeling, spill-proof. Low temperature: ~32% may solidify/freeze. Do not leave the container open for extended periods (CO2 intake).2).
Where can I buy liquid NaOH/caustic soda, and what documents do I need?
See the catalog of NaOH caustic soda from Loc Thien: NaOH (caustic soda) categoryPrepare the concentration (32/45/50%…), weight, delivery address, and COA/MSDS request per batch. Hotline: (+84) 979 891 929.
This content is for technical reference and basic chemistry education purposes only. It does not replace safety procedures, jar tests, or plant operating instructions (SOPs). Always use PPE and adhere to the MSDS of the batch being used.
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