Ammonium alum is sometimes referred to as just alum and is a white crystalline double sulfate that is used in very small amounts in a lot of different unique applications. Ammonium Alum is made from aluminum hydroxide, sulfuric acid and ammonium sulfate. When combined, it forms a solid solution with potassium alum. In terms of its use, ammonium alum is not a big industrial chemical or very useful in labs, but it is very inexpensive and nontoxic which is what invites so many individuals to use it. Among the list of uses for it, you’ll find that it is used in water purifications, porcelain cements, vegetable glues, tanning, dyes and fireproofing textiles and even in deodorants. Certainly not last in its many uses, this is also one of the most common ingredients when it comes to animal repellant sprays.