Ammonium aluminium sulfate

 CAS number 7784-25-0,

Appearance:- white crystals

Production and basic properties

Ammonium alum is made from aluminium hydroxide, sulfuric acid and ammonium sulfate. It forms a solid solution with potassium alum. Pyrolysis leaves alumina. Such alumina is used in the production of grinding powders and as precursors to synthetic gems.

Uses

Ammonium alum is not a major industrial chemical or a particularly useful laboratory reagent, but it is inexpensive and nontoxic, which invites many niche applications. It is used in water purification, in vegetable glues, in porcelain cements, in deodorants and in tanning, dyeing and in fireproofing textiles. The of the solution resulting from the topical application of ammonium alum with perspiration is typically in the slightly acid range, from 4 to 5.

Ammonium alum is a common ingredient in animal repellant sprays.

Toxicology

Aluminium sulfate, closely related to ammonium alum, is nontoxic with an of 6207 mg/kg. No human or ecological (for reduced concentrations) toxicity registered.