Potassium alum

• Alum
• Potassium
• Potassium aluminum sulfate dodecahydrate

Colorless octahedral crystals

Fixed

1.75 g · cm -3

92.5 ° C

Not available ( water of crystallization 60-200 ° C, decomposition 780 ° C ( anhydrous) )

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Aluminum potassium sulfate dodecahydrate, potassium aluminum sulfate dodecahydrate, potassium alum, potash alum or alum called, forms colorless octahedral crystals.

Properties

The solubility of aluminum potassium sulfate increases strongly with temperature. From hot saturated solution is great octahedron-shaped crystals can grow.

Use

It had earlier meaning in the tannery and the dyeing is, however, now displaced by aluminum sulfate.

Even today, it is sometimes used as a " Shaving " for hemostasis. Due to the odor reducing effect, it is included in some deodorants. It acts as an inhibitor in the decomposition of sweat in butyric acid.

In foods, it is added as a firming agent or stabilizer. It's 522 approved exclusively for egg white and glazed, candied or crystallized fruit and vegetables in the EU as a food additive called E.

Under the trade name LMA potassium alum is used against fire blight.