Potassium Alum

Potassium Alum (CAS No: 7784-24-9) Supplier in Europe

Potassium alum (Aluminum potassium sulfate, Aluminum potassium sulfate dodecahydrate) is a naturally occurring mineral that has long been prized for its astringent and antiseptic properties. Often seen as a crystalline, colorless solid, potassium alum is used in various applications, from water purification to serving as a key ingredient in deodorants and after-shave products.

This versatile compound is not only effective in keeping things clean but also gentle enough to be used in personal care products.

This compound’s ability to tighten and firm the skin makes it highly valued in the cosmetics industry.

Additionally, potassium alum is employed in the culinary world as a food additive, particularly in pickling recipes, for its ability to maintain the crispness of vegetables.

Its multifaceted nature allows it to fit seamlessly into multiple aspects of daily life.

Chemical Composition

Potassium alum, also known as potassium aluminum sulfate, is a chemical compound with the formula KAl(SO₄)₂·12H₂O. It is characterized by its crystalline form and white or colorless appearance.

The compound consists of potassium ions (K⁺), aluminum ions (Al³⁺), and sulfate ions (SO₄²⁻). These are combined in a 1:1:2 ratio.

This structure is key to its stability and effectiveness in various applications.

Hydration is a significant aspect of potassium alum. It contains twelve water molecules as part of its crystal lattice.

This hydrated form makes it soluble in water, which is essential for its use in both industrial and household contexts.

In pure form, the molecular weight of potassium alum is approximately 474.39 g/mol. This value includes the water content, highlighting the integration of water in its chemical makeup.

Uses in Industries:

• Water purification
• Dyeing processes
• Baking powder production

The balanced interaction of these components gives potassium alum its unique properties. This precise chemical composition ensures its versatility and effectiveness in a wide range of applications.

Physical Properties

Potassium alum, typically known for its crystalline form and water solubility, displays distinct characteristics. Understanding these properties is key for its various applications.

Crystal Structure

Potassium alum forms octahedral crystals, often exhibiting a regular geometric pattern. Its chemical formula is KAl(SO₄)₂·12H₂O, indicating the mineral contains water molecules.

The incorporation of these water molecules results in a hydrated appearance. When viewed under polarized light, the crystals often show well-defined shapes and angles.

The typical color of potassium alum crystals ranges from colorless to white and may include faint hues due to impurities.

The crystal’s hardness measures around 2-2.5 on the Mohs scale, making it relatively soft. This feature aids in its ability to be easily powdered or cleaved for various uses in industries such as dyeing and tanning.

Solubility

Potassium alum is highly soluble in water, which is an important factor for its practical applications. At room temperature, approximately 14.2 grams can dissolve in 100 milliliters of water.

As temperature increases, its solubility significantly improves, making it favorable for solutions requiring higher concentrations.

Its solubility decreases sharply in organic solvents, including alcohols, where it remains largely insoluble.

This property limits its use in non-aqueous applications but enhances its effectiveness in water-based processes.

Its hydrophilic nature is often exploited in applications like water purification and as a mordant in textiles to fix dyes permanently.

Applications

Potassium alum serves a diverse range of purposes. It plays a role in culinary practices, has several medical applications, and is used in various industrial processes.

Culinary Uses

Potassium alum is often used in the kitchen, particularly in pickling. It acts as a firming agent, helping to maintain the crispness of fruits and vegetables.

Additionally, it finds a place in baking powder formulations. The compound works as a leavening agent, providing lift and volume to baked goods.

Due to its astringent properties, it is sometimes incorporated in canned or preserved foods to enhance texture.

Although generally recognized as safe for consumption, moderation is advised due to its aluminum content.

Medical Uses

In the medical field, potassium alum is recognized for its astringent and antiseptic qualities.

It is commonly found in styptic pencils, which help stop minor bleeding from cuts and abrasions.

Additionally, it is employed in oral hygiene products like mouthwashes to reduce inflammation and bacteria.

Some traditional medicine practices also utilize it for its purported benefits in reducing perspiration and body odor.

While generally safe for topical application, care should be taken to avoid prolonged exposure, especially on sensitive skin.

Industrial Uses

Potassium alum plays a significant role in various industrial applications.

It is used in water purification processes, aiding in the removal of impurities by promoting coagulation.

In the textile industry, it functions as a mordant in dyeing, helping fabrics retain color.

Additionally, it is used in paper manufacturing to improve resistance to water and enhance the quality of finished products.

Its use extends into the cosmetics industry, where it serves as an ingredient in antiperspirants and deodorants.

Proper handling and disposal are necessary to minimize environmental impact.