Potassium Hydroxide (KOH): An Essential Strong Alkali for Modern Industry

From potassium salt production, detergents, and biodiesel to batteries, photovoltaics, and fine chemicals, potassium hydroxide is widely used across many modern industrial sectors.

Potassium hydroxide, with the chemical formula KOH, is also known as caustic potash. It is an inorganic compound characterized by strong alkalinity, high water solubility, and high chemical reactivity. Among its various commercial forms, 90% potassium hydroxide flakes are widely used due to their high active content and convenient storage and transportation.

1. Basic Information

• English name: Potassium Hydroxide

• Chemical formula: KOH

• CAS number: 1310-58-3

• Molecular weight: 56.11 g/mol

• Appearance: White or off-white flakes

• Melting point: Approximately 360°C

• Key properties: Strong alkalinity, high corrosiveness, strong hygroscopicity, and significant heat release when dissolved in water

KOH rapidly absorbs moisture from the air and reacts with carbon dioxide to form potassium carbonate. It should therefore be stored in tightly sealed, moisture-resistant packaging.

2. Main Product Grades

Potassium hydroxide can generally be classified by purity and intended use:

Grade	Typical Applications
Industrial grade	Potassium salt production, detergents, saponification, and gas treatment
Food grade	Food acidity regulation and processing aids
Reagent grade	Laboratory analysis, pharmaceuticals, and fine chemical synthesis
Electronic grade	Semiconductors, photovoltaic wafers, and precision etching

By physical form, KOH is commonly supplied as liquid, flakes, pellets, or powder.

Among these forms, 90% potassium hydroxide flakes offer relatively high concentration, convenient handling, and efficient transportation, making them suitable for a wide range of industrial processes and chemical formulations.

3. Production of 90% Potassium Hydroxide Flakes

Industrial potassium hydroxide is mainly produced by the electrolysis of potassium chloride solution:

2KCl+2H2​O→2KOH+Cl2​+H2​

Modern production generally uses membrane-cell electrolysis. Purified potassium chloride brine is introduced into the electrolytic cell, where KOH solution is produced together with chlorine and hydrogen as co-products.

The resulting liquid KOH is then concentrated by evaporation and cooled through drum flaking or other solidification equipment to produce potassium hydroxide flakes.

The “90%” designation refers to the active KOH content. The remaining portion mainly consists of water, potassium carbonate, and small quantities of other impurities.

4. Main Applications

Potassium Salt Production

KOH is an important raw material for producing potassium carbonate, monopotassium phosphate, potassium acetate, potassium formate, and other potassium salts.

For example, KOH reacts with phosphoric acid to produce monopotassium phosphate:

KOH+H3​PO4​→KH2​PO4​+H2​O

Monopotassium phosphate is widely used in water-soluble fertilizers, food processing, fermentation, and industrial formulations.

Detergents and Liquid Soap

KOH reacts with oils and fats through saponification to produce liquid soaps, soft soaps, industrial detergents, and certain personal care products.

Compared with sodium hydroxide, potassium hydroxide generally produces soaps with better water solubility.

Batteries and New Energy

KOH has good ionic conductivity and is used as an electrolyte in alkaline batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and certain zinc-air batteries.

It is also commonly used as an electrolyte in alkaline water electrolysis systems for hydrogen production.

Photovoltaic and Electronics Industries

KOH is used for silicon wafer etching and surface texturing in solar cell, semiconductor, and microelectronics manufacturing.

These applications generally require stricter control of chloride, iron, and other metallic impurities.

Biodiesel Production

KOH can be used as a catalyst in the transesterification of vegetable oils or waste oils with methanol, supporting the production of biodiesel.

Food, Pharmaceutical, and Environmental Applications

Food-grade KOH is identified as E525 and is mainly used as an acidity regulator and processing aid.

In pharmaceutical and fine chemical production, it is used for neutralization, salt formation, and intermediate synthesis. In environmental applications, it may be used for acidic gas absorption, wastewater pH adjustment, and chemical treatment.

5. Safety and Storage

Potassium hydroxide is highly corrosive. Operators should wear protective goggles, face shields, alkali-resistant gloves, and suitable protective clothing.

When preparing a solution, solid KOH should be added slowly to water under continuous stirring and cooling. This helps prevent violent heat release, boiling, and splashing.

In the event of skin or eye contact, rinse immediately with plenty of clean water and seek medical attention.

Storage requirements include:

• Keep tightly sealed and protected from moisture;

• Store in a cool, dry, and well-ventilated area;

• Keep away from acids and incompatible materials;

• Avoid contact with reactive metals such as aluminum and zinc;

• Use corrosion-resistant packaging and handling equipment.

Conclusion

Potassium hydroxide is not only an important strong alkali in traditional chemical manufacturing, but also a key raw material in batteries, renewable energy, photovoltaics, and high-purity chemical applications.

Among its commercial forms, 90% potassium hydroxide flakes are widely used because of their high active content, transportation efficiency, and broad industrial applicability.

When purchasing KOH, users should evaluate not only the stated KOH content, but also impurity levels such as potassium carbonate, chloride, sodium, and iron, together with packaging quality, moisture resistance, and batch-to-batch consistency.

Potassium Hydroxide (KOH): An Essential Strong Alkali for Modern Industry