Product Description
Aluminium potassium sulfate dodecahydrate (CAS No. 7784-24-9), commonly known as alum or potassium alum, is an inorganic sulfate compound with the chemical formula KAl(SO₄)₂·12H₂O. It typically appears as colorless transparent crystals or white crystalline powder and possesses characteristic astringent and antimicrobial properties.
Traditionally, alum has been widely used in medicinal applications due to its astringent effects and has been associated with functions such as moisture control, skin conditioning, and hemostatic support. Modern research has also demonstrated its antibacterial activity and potential applications in various biological studies.
In industrial fields, aluminium potassium sulfate dodecahydrate serves as an important raw material for producing aluminum salts and is commonly used as a flocculating agent in water purification, a tanning agent in leather processing, a mordant in dyeing, and an additive in papermaking and baking powder manufacturing.
Due to its versatile chemical properties and broad functionality, aluminium potassium sulfate dodecahydrate remains an important material in water treatment, chemical processing, traditional applications, and industrial manufacturing.
Chemical Properties
| English name | Aluminium potassium sulfate dodecahydrate |
| English synonyms | POTASSIUM ALUMINIUM SULFATE 12-WATER;POTASSIUM ALUMINIUM SULFATE DODECAHYDRATE:POTAS SIUM ALUM:POTASSIUM ALUMINUM SULFATE DODECAHYDRATE:POTASSIUM ALUM SULFATE, DODECAHY DRATE;POTASSIUM ALUM DODECAHYDRATE;POTASSIUM AMMONIUM SULFATE;aluminumpotassiumdisulf atedodecahydrate |
| CAS number | 7784-24-9 |
| Molecular formula | AIH8KO5S |
| Molecular weight | 186.2 |
| EINECS number | 616-521-7 |
| Melting point | 92°C (lit.) |
| Boiling point | 200°C |
| Density | 1.757 g/mL at 25°C (lit.) |
| Bulk density | 900 kg/m³ |
| Storage conditions | Store at +5°C to +30°C |
| Solubility | H2O: 0.5M, clear, colorless |
| Form | Solid |
| Specific gravity | 1.757 |
| Color | White |
| Odor | Odorless |
| pH | 3.0-3.5 (25°C, 50 mg/mL in H2O) |
| Water solubility | 140 g/L (20°C) |
| Merck | 14,360 |
| Stability | Stable. Incompatible with steel, aluminum, copper, zinc, alkalis, and strong oxidizers. |
| LogP | -1.031 (est.) |
Applications of Aluminium Potassium Sulfate Dodecahydrate (Alum) CAS No. 7784-24-9
Aluminium potassium sulfate dodecahydrate, commonly known as alum, is a versatile inorganic compound widely used in water treatment, papermaking, photography, textile processing, food applications, and pharmaceutical-related fields due to its excellent coagulation, astringent, and mordant properties.
Water Treatment Applications
Alum is commonly used as a flocculating and clarifying agent in water purification processes. It helps promote the aggregation and settling of suspended particles, improving water clarity and treatment efficiency.
Papermaking Applications
In the paper industry, alum is primarily utilized as a rosin sizing agent to enhance paper strength, improve water resistance, and optimize surface properties during paper production.
Photography Applications
Alum is used as a hardening agent in photographic processing, particularly in fixer solutions and photographic paper manufacturing, helping improve film stability and durability.
Textile Dyeing and Printing Applications
As an effective mordant, alum plays an important role in textile dyeing by improving dye fixation and color stability. It is also used in resist printing and anti-discharge dyeing processes to achieve better pattern definition and color performance.
Industrial and Specialty Applications
Alum is applied as a foaming aid in foam rubber production and serves as a functional additive in various industrial formulations. Its astringent properties also support applications in pharmaceutical preparations and topical products.
Food and Pharmaceutical Applications
Due to its functional properties, alum may be used in specific food processing applications and pharmaceutical formulations as an astringent, preservative aid, and topical hemostatic agent.
With its multifunctional performance, aluminium potassium sulfate dodecahydrate remains an important material for water purification, paper manufacturing, textile processing, photographic applications, and specialty chemical industries.
