Sodium Hydroxide(Caustic Soda Flakes)

Caustic Soda is a term mostly used by traders. As the substance has a corrosive and caustic feature, traders call it caustic soda. Another synonym for caustic soda, is sodium hydroxide which has been derived from its chemical properties as a sodium hydrate. This product is also known as lye and soda because of its strong alkali nature. As an alkali or base, caustic soda is soluble in water and cause other chemicals burn.

 Sodium Hydroxide: used mostly by chemists, because of its sodium ions, 

Caustic Soda: used mostly among traders, because of its corrosive and caustic feature, 

Lye and Soda: because of its strong alkali.

What are Various Forms of Caustic Soda?

Caustic soda can be found in many forms and types such as liquid, flakes, granular, cubes and blocks depend on the usage. However, the liquid and flake forms are far efficient than other types. Liquid caustic soda which is mainly produced in China, is suitable for pulp and paper industry, water and sewerage treatments and as additive in food industry. Producers and suppliers provide the market with liquid caustic soda as 50% and 73% solutions in water. Being environmentally friendly is the advantage of this form due to its moderate impact on environment. In water, sodium hydroxide is dissolved to sodium and hydroxide ion and become neutralized.

It is worth to mention that liquid form is much more energy-efficient. These pros are remarkable for eliminating energy waste and reducing final costs. Another popular form of this product is Flake, which absorbs water faster than Granular and cube. This feature results in less heat release and thus lowers the risk of explosion. In comparison to granular, cubes, and blocks, these two forms have more competitive prices, respecting higher production rates.

What are Caustic Soda Properties?

Caustic soda has usually a solid form. But be careful not to put it in a wet place, because the substance can absorb water very easily. If you dissolve caustic soda in water, it bubbles, splash and produce a reasonable amount of heat. That’s why it is recommended to keep caustic soda away from wet surfaces and humidity.

Caustic soda is also a corrosive substance. It reacts vigorously with some metals such as aluminum, magnesium, zinc, and tin. This kind of reaction may be hazardous and lead to explosion, mainly because a huge amount of hydrogen is generated. This means caustic soda cannot be handled without having safety rules in mind.




Specification of Caustic Soda Flakes 99.5% Purity

Test name


Degree important

Accepting Limit

Test Result

Test method

Purity of Sodium Hydroxide (NaOH)

% W


Min 98


IRISI-364 clause1-7/IRISI 6135

Carbonate as Na₂Co₃

% W


Max 1


IRISI-364 clause2-7/IRISI 6135

Chloride as NaCl

% W


Max 0.06


IRISI-364 clause3-7/IRISI 2535

Sulfate as Na₂So₄

% W


Max 0.01


IRISI-364 clause4-7/IRISI 2539

Silicate as SiO2

% W


Max 0.02


IRISI-364 clause5-7/IRISI 2531




Max 30


IRISI-364 clause6-7/IRISI 2537

Insoluble in water

% W


Max 0.1


IRISI-364 clause7-7/IRISI 7904

Aluminum as Al₂O₃



Max 20


IRISI-364 clause8-7/IRISI 7903

Heavy metals as Pb



Max 20


IRISI-364 clause9-7/IRISI 7905

What is the difference between sodium hydroxide and potassium hydroxide?

Both sodium hydroxide and potassium hydroxide (KOH) are used as catalyst in a wide range of industries. However, these two chemical compounds have differences.

Sodium hydroxide is stronger than potassium hydroxide in terms of reactivity. However, KOH is more soluble in water, ethanol and methanol.

Due to its wider range of applications, potassium hydroxide is cheaper than caustic soda. In the manufacturing of fertilizers, soaps and chemical batteries, it is potassium hydroxide that plays a vital role, not caustic soda.

What is the difference between caustic soda and Soda Ash?

Despite their Alkali feature, Sodium Hydroxide and Sodium Bicarbonate are not the same. Sodium Bicarbonate is also known as Soda ash by Na2CO3 Formula. Being less hazardous than sodium hydroxide, this chemical substance is used for reducing the acidity in cooking, baking, and even medicine.

It is also a raw material in glass manufacturing. Because of its alkali nature, it has a vital role in shaping the glass items. It also supports the energy efficiency by reducing the temperature of furnace which is a must to melt the silica (the main raw material of glass). Soda ash is also useful in mixing other raw materials in the production of glass. It prevents the mixture from being segregated and solidified.