Ammonium sulfate (sometimes abbreviated as AS or AMS) has been produced for over
150 years. Initially, it was made from ammonia released during manufacturing coal gas
(used to illuminate cities) or from coal coke used to produce steel. It is made from a reaction
of sulfuric acid and heated ammonia. The size of the resulting crystals is determined
by controlling the reaction conditions. When the desired size is achieved, the crystals are
dried and screened to specific particle sizes. Some materials are coated with a conditioner
to reduce dust and caking.
Most of the current demand for ammonium sulfate is met by production from by-products of various industries. For example,
ammonium sulfate is a co-product in the manufacturing process of nylon. Certain by-products that contain ammonia or spent
sulfuric acid are commonly converted to ammonium sulfate for use in agriculture. Although the color can range from white to
beige, it is consistently sold as a highly soluble crystal that has excellent storage properties. The particle size can vary depending
on its intended purpose.