What is Sodium Hydroxide (NaOH)? Characteristics and Applications | Loc Thien

Sodium hydroxide (NaOH) is one of the most widely consumed industrial chemicals in the world and a strategic item in the product portfolios of many Vietnamese factories. From kraft paper production lines and fabric bleaching lines to wastewater neutralization systems and detergent formulations, NaOH is present in almost every industrial production sector. Therefore, a proper understanding of its properties, product forms, and safety requirements is essential for businesses to optimize costs and control risks during operation.

This article compiles technical information and purchasing practices for sodium hydroxide (NaOH) — from its physicochemical characteristics and how to distinguish between the three types of products on the market, to safety guidelines and criteria for selecting reputable suppliers with complete CO/CQ certificates and VAT invoices. The information is compiled based on practical experience serving B2B customers and references. PubChem – Sodium hydroxide, ILO ICSC 0360 – Sodium Hydroxide and genuine MSDS documents.

If your business needs a quick quote for bulk orders or advice on selecting the right product type for your production line, please check out the section below. Loc Thien supplies NaOH caustic soda. at the end of the article.

What is sodium hydroxide (NaOH)?

Nomenclature, formula, CAS number, and synonyms.

NaOH — short for sodium hydroxide — is an inorganic compound consisting of one sodium (Na), one oxygen (O), and one hydrogen (H) atom bonded together in an ionic structure. It is known by many different commercial names: caustic soda, industrial caustic soda, caustic soda, lye, or simply xut In Vietnamese, in the chemical industry, the CAS (Chemical Abstracts Service) code is 1310-73-2 — A unique identifier used globally for securely retrieving data and international trade documents.

When transported by road or water, NaOH is classified according to the UN code: UN1823 for solid form (flakes, granules) and UN1824 For liquid form, classified as hazardous material category 8 — corrosive substances. Valid shipping documents and product labels must clearly state this code in accordance with the IMDG Code and Decree 34/2024/ND-CP.

Forms of existence: flakes, granules, and liquid.

Commercially available sodium hydroxide (NaOH) exists in three main physical forms: white scales (flakes) small seeds (pearls/beads) and fluid (Liquid caustic soda). All three forms are the same compound, but differ in concentration, form, and preferred application. Choosing the right form from the outset helps businesses optimize transportation costs, simplify mixing ratios, and avoid unnecessary operational risks.

Why is it called caustic soda?

The name "caustic soda" comes from NaOH's highly corrosive properties towards biological tissues. When it comes into contact with skin, the alkaline solution breaks peptide bonds in proteins and decomposes lipids in cell membranes, causing a type of chemical burn called an alkali burn. It is particularly more dangerous than acid burns because the alkali continues to penetrate deeper into the tissue even after the surface has been washed, so pain may be felt later and the actual damaged area may be larger than initially visible.

Characteristics and properties of NaOH

Basic physical properties

Under standard conditions, pure NaOH is an opaque white, odorless solid with a molecular weight of 40,00 g/mol, a melting point of 318 °C, and a boiling point of 1.388 °C. Its density is approximately 2,13 g/cm³ in solid form. In water, NaOH dissolves very well and completely dissociates into Na⁺ and OH⁻ ions, forming a strong alkaline solution with a pH close to 14 at a concentration of 1 M. The NaOH solution is clear and colorless (or slightly yellowish if it contains iron impurities).

Chemical properties and exothermic reactions

NaOH is a typical strong base, reacting with acids to form salt and water (neutralization reaction), reacting with CO₂ in the air to form Na₂CO₃ (sodium hydroxide), and reacting with amphoteric metals such as aluminum and zinc to release flammable hydrogen gas. This is why NaOH should absolutely not be used in aluminum or zinc equipment.

The reaction of dissolving NaOH in water is highly exothermic—the enthalpy of dissolution is approximately −44 kJ/mol. This means that adding 1 kg of caustic soda flakes to 5 liters of water can raise the solution temperature above 70–80 °C if the rate of addition is not controlled. The golden rule is... Always add NaOH to the water, never the other way around., so that the heat generated is distributed throughout the entire mass of water.

Moisture absorption capacity, CO₂ absorption, and preservation consequences.

Solid NaOH is highly hygroscopic—it absorbs moisture from the air very quickly, causing the flakes/granules to become damp, sticky, and eventually liquefy within the packaging if left open. Simultaneously, NaOH absorbs CO₂ to form Na₂CO₃, reducing its purity over time. These two phenomena necessitate airtight packaging, a dry storage environment, and a FIFO (first-in, first-out) inventory turnover.

Types of NaOH (sodium hydroxide) available on the market

This is the most common question B2B customers ask when placing their first order: Should I buy flakes, granules, or liquid? The answer depends on the production process, warehouse capacity, frequency of use, and mixing conditions of each factory.

Caustic soda flakes 98–99%

Sodium hydroxide flakes (NaOH flakes) have a NaOH content ranging from 98% to 99%The caustic soda flakes are flat, white, irregularly sized, and easily crumbled. This is the most common form on the Vietnamese market due to its reasonable price, ease of weighing, and easy solubility when added to water. Caustic soda flakes are packaged in double-layered PE bags or kraft-PE bags, with standard weights. 25 kg/bagSuitable for soap factories, small and medium-sized wastewater treatment plants, paper bleaching lines, and for preparing alkaline solutions of customizable concentrations. Product details can be found on the website. 99% NaOH flakes by Loc Thien.

99% granular caustic soda

Sodium hydroxide (NaOH pearls/beads) has a high content. 99 %The spherical particles are uniform in size and shape, more consistent than caustic soda flakes, making them more convenient for automatic dosing systems or screw conveyors. The uniform particle surface also helps to ensure a stable and more controllable dissolution rate in continuous processes. Standard packaging is also available in bags. 25 kgIn the pharmaceutical, cosmetic, and food industries—where high levels of cleanliness and strict impurity control are required—food-grade/pharma-grade granular caustic soda has additional certifications according to TCVN or USP standards.

Liquid caustic soda 20%, 32%, 45%, 50%

Liquid caustic soda is a pre-mixed solution of NaOH at common commercial concentrations: 20%, 32%, 45% , and 50 %This is the optimal choice for large, continuous-consumption plants with existing tank pumping systems — as it requires no dissolution step, produces no NaOH dust, and is fed directly into the production pipeline. A 50% concentration is commonly used in large paper mills and chlor-alkali plants; a 32% concentration is more common in wastewater treatment plants and textile factories; and a 20% concentration is often used in some cleaning and pH adjustment processes.

Liquid caustic soda is delivered by Plastic cans, 200-liter drums, 1.000-liter IBC tanks or specialized tank trucks depending on the order quantity. Please note that high-concentration liquid caustic soda (45–50%) can crystallize at low temperatures, so storage facilities must maintain the minimum temperature specified in the batch's MSDS. Detailed specifications can be found on the page. Liquid sodium hydroxide (NaOH) 20%–50%.

How to choose the right format for each system

Applications of NaOH (sodium hydroxide) in industry

Paper, pulp, and ink removal.

The paper and pulp industry is the world's largest consumer of NaOH. In the kraft (sulfate pulping) process, NaOH combines with Na₂S to form white liquor, which breaks down lignin in wood and releases cellulose fibers. After the cooking process, NaOH also participates in pulp bleaching and black liquor recovery. In the paper recycling industry, NaOH is used for deinking used newspapers and office paper. Further information on the product catalog supporting this industry can be found on this page. Paper and pulp chemicals.

Soap, detergents, and petroleum products

The production of bar soap and hard soap uses NaOH as a saponification agent—it reacts with vegetable oils or animal fats to produce fatty acid salts (soap) and glycerol. This industrial process, dating back hundreds of years, remains common in both artisanal and large-scale industrial production. In the cleaning industry, NaOH is a key component of industrial degreasing agents and CIP (clean-in-place) cleaners for food and beverage pipelines. In oil and gas exploration, NaOH is used to adjust the pH of drilling fluids and treat extraction water. Related product catalogs can be found on this page. Industrial cleaning chemicals.

Textile dyeing, wastewater treatment, and aluminum

The textile dyeing industry uses NaOH in the mercerizing process—soaking cotton fibers in a concentrated NaOH solution to increase gloss, durability, and color absorption. NaOH is also used to prepare fibers before dyeing and to treat synthetic fabrics. Details on textile dyeing chemicals can be found on this page. Textile dyeing chemicals by Loc Thien.

In industrial wastewater treatment, NaOH is the most common acid-neutralizing agent — raising the pH of acidic wastewater to a safe level. QCVN 40:2011/BTNMT (pH 6–9) before discharge into the receiving water source. In alumina refining (Bayer process), sodium hydroxide (NaOH) dissolves bauxite ore to separate alumina from silicate and iron oxide impurities. Further wastewater treatment applications are supported by the page. Wastewater treatment chemicals.

Food and food safety guidelines

Food-grade NaOH is permitted for use as a pH regulator (INS 524) according to the Codex Alimentarius standard and regulations of the Vietnamese Ministry of Health. Typical applications include: processing black olives (curing), producing pretzel bread and lye wash, and processing cocoa in the production of Dutch process cocoa. In all food applications, NaOH must meet much stricter heavy metal impurity criteria than the common industrial grade — requiring a Certificate of Analysis (CoA) and MSDS of the correct grade before ordering.

Reference specifications

Common quality indicators

Note: The exact values ​​for impurities (Na₂CO₃, NaCl, Fe) depend on the manufacturer and batch. Businesses should request specific Certificates of Analysis (CoA) and MSDS when placing orders to compare with internal process requirements.

Packaging, shipping, and storage conditions

Caustic soda flakes and granules are packed in 25 kg double-layer PE bags, stacked on pallets of 40–50 bags (1–1,25 tons/pallet), and covered with PE tarpaulin when transported outdoors. Storage facilities must have a dry, waterproof, well-ventilated concrete floor and be located away from areas containing acids and oxidizing chemicals. Liquid caustic soda is transported in specialized tanker trucks with corrosion-resistant plastic or stainless steel liners. The trucks must display the UN 1824 sign and hazard symbol class 8 as stipulated in Decree 34/2024/ND-CP on the transport of dangerous goods.

When is it necessary to check Vietnamese National Standards (TCVN) and MSDS?

Businesses should request MSDS (Material Safety Data Sheet) and CoA (Certificate of Analysis) for every shipment, especially when: (1) changing suppliers, (2) changing the country of origin of goods, (3) applying to processes requiring food grade/pharma grade, (4) serving ISO 14001/ISO 45001 audits or regulatory inspections. Reputable suppliers must provide a complete set of these technical documents for each shipment, not just for a general product code.

Safety guidelines for using NaOH.

PPE is required when working with NaOH.

According to the recommendations of ILO ICSC 0360The personal protective equipment (PPE) required when handling NaOH includes:

• Chemical splash goggles — mandatory, not a substitute for regular glasses
• Face shield — when handling large quantities or dilution
• Alkali-resistant gloves (butyl rubber or neoprene) — Do not use thin latex gloves
• PVC apron or full-body protective clothing when working with large quantities
• Chemical-resistant safety shoes — do not wear open-toed sandals
• P2/P3 Dust Mask When handling caustic soda flakes/solid granules (to prevent alkaline dust)

Rules for proper dilution

An indispensable principle: Always add NaOH to water, never pour water into NaOH.Conversely, if the water is diluted, all the reaction heat will be concentrated in it, causing violent boiling and splashing of the concentrated alkaline solution. Safe dilution procedure:

1. Make sure you have enough plastic wrap before opening the NaOH bag/container.
2. Measure the required amount of water into a heat-resistant, alkali-resistant container (HDPE plastic, stainless steel — do not use aluminum).
3. Add NaOH slowly to the water, stirring well after each addition.
4. Monitor the temperature — if it exceeds 80°C, stop, wait for it to cool down, and then continue.
5. After mixing, allow the solution to cool completely before transferring it to the system.

First aid for skin contact, eye contact, and inhalation.

Skintight: Immediately remove contaminated clothing and wash the affected skin area with clean, running water for at least a short period. minDo not neutralize with acid. After first aid, seek medical attention immediately, even if you only experience mild irritation, as alkali burns can have long-term consequences.

Eye contact: Rinse your eyes immediately at an emergency eyewash station with clean water continuously for at least a short period. 20–30 minutesKeep the eyelids open throughout the process. This is an emergency — immediate transport to an ophthalmology hospital is necessary after first aid due to the high risk of blindness.

Inhalation: Immediately move the victim to a well-ventilated area and have them rest in a sitting position if they have difficulty breathing. If symptoms such as persistent coughing, sore throat, or difficulty breathing occur, seek medical attention as NaOH dust/vapor can damage the upper respiratory tract.

Where to buy NaOH (caustic soda)? Loc Thien provides nationwide delivery.

Criteria for selecting a B2B NaOH caustic soda supplier.

When ordering NaOH caustic soda in industrial batches, businesses should evaluate suppliers based on the following criteria: (1) having a physical warehouse with sufficient and stable inventory; (2) providing complete CoA and MSDS for each batch; (3) issuing electronic VAT invoices on time; (4) having the ability to deliver inter-provincially and providing suitable vehicles (trucks for solid caustic soda, tank trucks for liquid caustic soda); (5) providing technical support on grade selection, concentration, and MSDS consultation when needed. A complete list of industrial chemicals is available on the website. Basic chemicals.

Certificate of Origin/Quality, VAT invoice, and nationwide delivery.

For import orders, Certificate of Origin (CO) and Certificate of Quality (CQ) are crucial documents for verifying the origin of goods, serving accounting purposes, internal audits, or meeting the requirements of end customers. Shipments imported from China, Taiwan, or South Korea must have a complete set of these documents if ordered through a capable distributor. Loc Thien provides CO/CQ by batch, electronic VAT invoices, and customs declarations for orders requiring them — businesses should confirm their specific needs when contacting us for a quote.

Contact Loc Thien to get a quote for NaOH caustic soda.

Loc Thien Company is the distributor. basic chemicals We are a professional supplier of 98-99% NaOH flakes, 99% granular caustic soda, and 20-50% liquid caustic soda, with complete technical and commercial documentation. We deliver nationwide – from industrial zones in Ho Chi Minh City, Binh Duong, and Dong Nai to factories in Central and Northern Vietnam. Orders of 500 kg or more are eligible for wholesale pricing and scheduled delivery.

Frequently Asked Questions about Sodium Hydroxide (NaOH) (FAQ)

Reference source: PubChem – Sodium Hydroxide (CID 14798); ILO ICSC 0360 – Sodium Hydroxide; QCVN 40:2011/BTNMT – Industrial Wastewater