Manufacturing Process of Ammonium Alum

Ammonium alum has evolved into an extremely useful and profitable mineral salt. Through scientific breakthroughs and manufacturing evolution, ammonium alum is created by the hydrometallurgy of two single sulfates, ammonium sulfate and aluminum sulfate, which thereby form the crystalized double sulfate, ammonium aluminum sulfate, also known as ammonium alum.


Key Components


The main chemical component for the creation of ammonium sulfate is ammonia. Ammonia is one of the most, if not the most important chemical of 20th and 21st century due to the ability to create fertilizer, and as a direct result aid population growth via increased food production. The commercial production of ammonia is done through the Haber-Bosch process, where by the direct combination of nitrogen and hydrogen at temperatures in the range of 400oc to 600oc catalyze the reaction and yield ammonia.

Sulfuric Acid

A main component of both single sulfate production processes is sulfuric acid,
which is a
colorless, odorless, extremely corrosive, oily liquid. It is one of the oldest discovered chemicals, being discovered around the 16th century, as well as currently being one of the most important industrial chemicals. In the U.S. alone, more than 40 million tons are produced each year. The contact process, which consists of making sulfur dioxide, converting the sulfur dioxide into sulfur trioxide, and then converting the sulfur trioxide into concentrated sulfuric acid. Concentrated sulfuric as is what is needed for industrial manufacturing, and the contact process is currently the most economical way of production.


Step 1

The first step of the manufacturing process is the formation of the two single sulfates. Each single sulfate is formed through the sulfuric acid (H2SO4) leaching of its respective second chemical component: ammonia (NH4) and Aluminium trihydroxide (Al(OH)3):

Ammonia + Sulfuric Acid = Ammonium Sulfate

Aluminium trihydroxide + Sulfuric Acid = Aluminum Sulfate

Step 2

The second step of the manufacturing process is the combining of the two single sulfate aqueous solutions to form a crystalized ammonium aluminum sulfate, which is done through a process called hydrometallurgy.

Ammonium Sulfate + Aluminum Sulfate = Ammonium Aluminum Sulfate (Ammonium Alum)

Additional Process

Another option to synthesize ammonium alum is by using the chemicals resulting from the Caprolactam process. Thousands of tons of ammonium salts are manufactured monthly in Thailand that can easily be used in this process.