Certain properties of potassium hydroxide make it an extremely versatile cleaning agent. This ScienceStruck article presents the uses of this compound in various industries like cosmetics, food, agriculture, and petrochemicals. Know the characteristic properties of potassium hydroxide, and how it is used in day-to-day life.

Did You Know?

Being highly reactive, pure potassium is not found free in nature. It is present in ionic salts and in some minerals. It can be obtained in its pure form through the electrolysis of its hydroxide or its chloride. It was first isolated through electrolysis by Sir Humphry Davy in 1807. It was the first elemental metal to be found through electrolysis.

Potassium hydroxide, commonly known as caustic potash or lye, is a water-soluble compound, which has myriad applications in industry. This solid, odorless, and colorless compound is represented by the formula KOH. It is a strong base and when dissolved in water, produces a significant amount of heat. It is available in the form of white or slightly yellow lumps, rods, and pellets.

Sodium hydroxide or caustic soda (NaOH) exhibits properties that are similar to those exhibited by KOH. Moreover, it is available at a relatively lower cost. So, many times, it is used as a substitute of KOH in various industries.

Characteristic Properties

Following properties make KOH a very useful compound for various industrial processes.

✦Corrosive nature
✦Ability to degrade various materials
✦High affinity for water
✦ High thermal stability
✦ Comparatively low melting point
✦Reactivity toward acid
✦A strong chemical base

Uses and Benefits

Understanding the nature and benefits of various chemical compounds is an interesting topic. Some of the common uses of potassium hydroxide are described here. It is difficult to enlist all uses as it has uses in a wide array of fields and industries.

In Agriculture

• KOH is used to produce fertilizers which supply the element potassium (one of the major plant foods) to crops, especially to those crops which cannot tolerate chloride ions.

• It is used in herbicides and fungicides.
• It helps regulate the pH of acidic soils.
• A mixture of phosphorous acid (non-pesticide compound) and KOH is regularly sprayed on plants for pests and disease prevention. The crops that are collected will not have pesticide remains.

In Batteries and Fuel Cells

Battery Cells

• Potassium hydroxide dissolved in water works as an electrolyte in alkaline, nickel-cadmium, and manganese dioxide-zinc batteries.

Fuel Cells

• It acts as an electrolyte in fuel cells too. KOH solutions are better conductors of electricity than NaOH solutions.

In Chemical Laboratories

Chemical Laboratory

• KOH test helps detect fungal infection on skin.
• It is used to produce potassium salts that are used in various processes. For example, potassium cyanide is used in gold mining and electroplating, while potassium permanganate is widely used as a disinfectant. Potassium phosphate is used to produce fertilizers.
• It is used to produce several potassium chemicals, such as potassium aluminate, bromate, bromide, formate, gluconate, laurate, etc.
• It is used to counterbalance acidity and adjust the pH of solutions.
• It helps study insect anatomy as it speeds up the process of decomposition of soft tissues.
• It acts as a desiccant (promotes drying) and is used to dry basic solvents, especially amines and pyridines.
• It is required in various analytical procedures. For example, it helps determine the concentration of acids.
• Some species of agaricales (gilled mushrooms), polypores (bracket fungi), boletes, etc., are identified by observing the color change after application of an aqueous solution of KOH on them.

In Petrochemical Industry

Petrochemical Industry

• During petroleum and natural gas refining processes, it helps get rid of organic acids and sulfur compounds.
• It plays the role of a catalyst when biodiesel is produced from oils and fats. The by-product glycerin is detoxified and used to feed cattle.
• Carbon dioxide (CO₂), sulfur trioxide (SO₃), and nitrogen trioxide (NO₃) found in gas streams are absorbed with the help of KOH.

In Food Industry

In Food Industry

Food Industry

• It is used to wash fruits in factories. Chemical peeling of fruits and vegetables also involves use of KOH.
• It is used to produce caramel color.
• It is required for processing soft drinks, chocolate, and cocoa.
• Commercially processed foods contain KOH. It is widely used as a food additive, because it acts as a thickener (for example, in ice creams) and stabilizer. It helps increase the shelf life of the food.
• It helps soften olives, but at the same time, it makes pretzels crisp.

In Medical Field

Medical Field

• It is used to destroy calves horns. It helps get rid of the scales and hair.
• In humans, it is used to determine whether a person has a fungal infection. It is also used to dissolve warts and cuticles.

In Cosmetics and Cleaning Products

Cleaning Products

• Saponification of fats with KOH is useful for the production of potassium soaps. Although soaps that are produced using sodium hydroxide are more common, potassium soaps are softer than these soaps and are more soluble too (need less water to become liquid). Thus, they contain higher amount of cleaning agent than liquefied sodium soaps. This is the reason why liquid soaps are potassium soaps, and solid soaps are sodium soaps. KOH is present in non-phosphate detergents.
• It is present in products that are used for unclogging drains and pipes.

Cosmetics Product

• It is present in manicure products that are used to clean nails.
• Its use in shaving products that promote easy removal of hair.
• It is used to produce various types of lotions, shampoos, hairsprays, etc.
• Not only denture cleaners but oven cleaners, driveway and concrete cleaners also contain KOH.
• It is present in paint and varnish removers.

Other Industries

Textile Industry

• It is required in printing as well as pulp and paper manufacturing industries. It helps separate lignin from cellulose fibers and helps get rid of foam in the manufacturing process of paper.
• In various industries, it is used to remove grease or oil from metals.
• In the textile industry, it is used as a bleaching agent.
• It is used in the manufacturing of printed circuit boards.

Leather Industry

• Photochemical developers contain KOH.
• It is used in the manufacturing processes of certain micro-electronic devices.
• In the leather industry, KOH plays an important role in the removal of hair from animal hide. It is present in leather tanning chemicals.
• When used in chemical cremation, it speeds up decomposition of tissues. It promotes quick dissolution of animal carcasses.

Potassium hydroxide is corrosive to the skin and eyes. It can damage the tissues and can cause severe burning sensation. It can irritate the nose and throat when inhaled. Therefore, it should be handled cautiously and carefully.