Salts & Minerals
REACH
Aluminum potassium sulfate dodecahydrate
CAS Number
7784-24-9
EC Number
616-521-7
E Number
E522
What is Aluminum potassium sulfate dodecahydrate?
Aluminum potassium sulfate dodecahydrate (CAS 7784-24-9), commonly known as potassium alum or E522, is the fully hydrated crystalline form of alum.
Where is Aluminum potassium sulfate dodecahydrate used?
- Water treatment: coagulant that aggregates suspended particles
- Food processing: firming agent and leavening component in baked goods, pickles and starch-based products
- Leather tanning and textile dyeing: dye fixative and mordant
- Paper manufacturing: sizing control by precipitating rosin onto cellulose fibers
- It functions as a coagulant, flocculant and pH buffer.
Commercial specifications
- Food-grade (FCC, E522-compliant) and technical grade
Other Names (Synonyms)
aluminum;potassium;disulfate;dodecahydrate|ALUMINUM POTASSIUM SULFATE DODECAHYDRATE [MI]|RefChem:556689|Potassium alum dodecahydrate|Aluminium potassium sulfate dodecahydrate|Potash alum dodecahydrate|Potassium aluminum disulfate dodecahydrate|Sulfuric acid, aluminum potassium salt (2:1:1), dodecahydrate|E522
What are the physical properties of Aluminum potassium sulfate dodecahydrate?
Melting Point 92.5 °C
Boiling Point 200°C
Density 1.75 g/cm³ (solid)
Appearance white to colourless crystals
Color White
Odor Odorless
Form Solid
Water Solubility 140 G/L (20 ºC)
pH 3.0-3.5 (25℃, 50mg/mL in H2O)
Log P -1.031 (est)
Which trade and regulatory codes apply to Aluminum potassium sulfate dodecahydrate?
HS Code 28332990
WGK (Germany) 3