Sodium hydroxide (caustic soda) is a common strong base, massively used in the industry. It’s an ingredient of choice to increase the alkalinity of a compound or to neutralize acids.


Chemical name: Sodium hydroxide

CAS No.: 1310-73-2

Molecular formula: NaOH

Standard executed: GB 209-2006

Packaging: in 25KG PP woven bag with PE liner


Technical specification

Items Standards
Purity (NaOH), %
Na2CO3 content, %
NaCl content, %
Fe2O3 content, %
Flash point
non-combustible solids, but when in contact with water may generate sufficient heat to ignite combustible materials.
Melting point
323 °C (613 °F, 596 °K)
Boiling point
1388 °C (2530 °F, 1661 °K)
2.13 g/cm3
Vapor pressure
<2.4 kPa (at 20 °C)
Water Solubility
pH range
Strongly alkaline (1% solution)
Air sensitive, Hygroscopic
In original container. Dry. Well closed. In an area without drain or sewer access. Separated from food and feedstuffs, strong acids and metals.
Shelf life/Retest
24 months
White crystalline pearls or flakes


Around half of the sodium hydroxide production is used by manufacturers, prevalently in the paper industry. Other applications include the manufacturing of sodium salts and detergents, pH regulation, and organic synthesis.

In the petroleum industry, sodium hydroxide is utilized as an additive in drilling mud. It increases the mud viscosity and alkalinity in bentonite mud systems. Additionally, caustic soda neutralizes any acid gas encountered in the geological formation as drilling progresses. The process known as caustic washing utilizes caustic soda to clean and improve low quality crude oil. Treating with sodium hydroxide eliminates sulfurous impurities through reaction with weak acids.

Sodium hydroxide is broadly applied in the pulping of wood for creating paper or regenerated fibers. It plays a crucial role in several later stages of bleaching the brown pulp emerging from the pulping process. All of these stages require a strongly alkaline environment with a pH > 10.5 at the end of the phase.

Sodium hydroxide reacts with aluminum and water to produce hydrogen gas and sodium aluminate. This reaction converts a polished surface to a satin-like finish. In the biodiesel industry, anhydrous sodium hydroxide is a catalyst for the transesterification of methanol and triglycerides.

Food uses include washing or chemical peeling of fruits and vegetables, as well as chocolate, cocoa and soft drink processing, caramel coloring, poultry scalding, and thickening ice cream. Olives can be soaked in sodium hydroxide for softening. Furthermore, pretzels and German lye rolls are glazed with a sodium hydroxide solution before baking to achieve crispiness.

Another broad usage of sodium hydroxide is in the production of parts washer detergents. This includes defoamers, surfactants, and rust inhibitors. A parts washer heats detergent and water in a closed cabinet, spraying them at pressure against dirty parts for degreasing applications. While parts washer detergents based on sodium hydroxide are among the most aggressive parts washer cleaning chemicals, they are also considered environmental improvements over the solvent-based cleaning methods.

Stability/Shelf life

Hygroscopic. Air-sensitive.

Recommended storage: Must be stored in airtight containers to preserve its normality as it will absorb water from the atmosphere. Follow proper NaOH storage guidelines and maintain worker/environment safety.


Caustic soda is industrially produced as a 50% solution by electrolysis of sodium chloride solution. The variations of the electrolytic chloralkali process feature one of three cell types: mercury, diaphragm, and membrane cells. In the mercury cell, sodium is emancipated in the form of a mercury sodium amalgam, while chloride ions as chlorine. The amalgam flows to a completely separate compartment where it counters with water to generate sodium hydroxide solution and hydrogen gas. Solid sodium hydroxide is obtained by the evaporation of water from the solution, to make flakes, prills, and cast blocks.

Industry use

Sodium hydroxide is utilized in the manufacture of textiles, pulp and paper, drinking water, soaps and detergents, and as a drain cleaner. 

Consumer use

Sodium hydroxide is used in various food processing applications, such as curing olives, removing skins from fruits and vegetables for canning, and as a preservative to prevent mold and bacteria from growing in food. 

Sodium hydroxide is also a traditional saponifier in the cold process of soap crafting.


Solubility in water, g/100ml at 20℃: 109 (very good)

Common synonyms

  • Caustic Soda
  • Lye
  • Ascarite
  • White caustic
  • Sodium hydrate

Ask an expert

Did we forget something? Do you have a specific issue that needs a solution? Consider it done! Our professionals are at your service 24/7, ready to answer every question in a clear and concise manner.

We do supply Caustic soda lye for China market. But due to transportation inconvenience, we do not supply Caustic soda lye internationally, but Caustic soda flakes and pearls.

No, we don’t supply Caustic soda food grade. STPP Group has only been dedicated to the Home Clean & Cleaning industry. We only supply Caustic soda for detergent and soap production.

STPP Group does not manufacture Caustic soda. We have been partnering with 3 of China’s top 5 manufacturers of Caustic soda, for consumption in STPP Group’s 3 detergent factories and supplying to our 100+ global customers.

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