Potash alum
CAS 7784-24-9
EC 616-521-7
Formula Al.2H2O4S.12H2O.K
MW 474.39 g/mol
Salts & Minerals Water TreatmentTextile, Leather & PaperFood & NutritionPersonal Care & Cosmetics Preservation & BiocideCoagulation & FlocculationAntioxidant & StabilizerCatalysis
Description
Potassium alum (CAS 7784-24-9) is a double sulphate salt of potassium and aluminium, commercially known as alum or potash alum and supplied under the formula AlK(SO4)2·12H2O. It carries EC number 616-521-7 and has no assigned E-code for food applications in the EU.
In water treatment, potassium alum acts as a coagulant by releasing aluminium ions that destabilise suspended particles, enabling flocculation and sedimentation. In leather tanning and textile processing, it functions as a mordant and preservative, binding dyes to fibres and inhibiting microbial degradation of hides during processing.
Potassium alum is available in technical, food-grade, and reagent grades, with compliance references including FCC and Ph.Eur. monographs where applicable. The product falls under REACH regulation and is classified under HS code 28332990. Packaging typically includes 25 kg bags and bulk options depending on grade and application requirements.
In water treatment, potassium alum acts as a coagulant by releasing aluminium ions that destabilise suspended particles, enabling flocculation and sedimentation. In leather tanning and textile processing, it functions as a mordant and preservative, binding dyes to fibres and inhibiting microbial degradation of hides during processing.
Potassium alum is available in technical, food-grade, and reagent grades, with compliance references including FCC and Ph.Eur. monographs where applicable. The product falls under REACH regulation and is classified under HS code 28332990. Packaging typically includes 25 kg bags and bulk options depending on grade and application requirements.
Physical Properties
| 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) |
Trade & Regulatory
| HS Code | 28332990 |
| WGK (Germany) | 3 |
Other Names
Potassium AlumAlK(SO4)2.12H2Opotash alum dodecahydratealuminum potassium sulfate dodecahydrateALUMALUMINUM POTASSIUM SULFATEALUMINIUM POTASSIUM SULFATE
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Raw Materials
Derivatives
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