Ammonium Sulfate

What is Ammonium Sulfate used for?

Fertilizer

The primary use of ammonium sulfate is as a fertilizer for alkaline soils. In the soil the ammonium ion is released and forms a small amount of acid, lowering the pH balance of the soil, while contributing essential nitrogen for plant growth.

Food Additives | Acid Regulator (E517)

As a food additive, ammonium sulfate is considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration, and in the European Union it is designated by the E number E517. It is used as an acidity regulator in flours and breads.

Treatment of drinking water

In the treatment of drinking water, ammonium sulfate is used in combination with chlorine to generate monochloramine for disinfection.

How is Ammonium Sulfate produced?

Ammonium sulfate can be obtained in a variety of ways, some of which are industrially produced, and some of which are by-products of certain industrial processes that are further processed or used.

Recovery of ammonium sulfate from wastewater containing sulfuric acid or ammonia

In industrial terms, ammonium sulfate is produced as a by-product in some chemical processes, especially in the production of caprolactam. Coarse-grained products (in the range of 2 to 4 mm) can be produced from such ammonium sulfate-containing wastewater in so-called DTB (Draft Tube Baffle) or Oslo crystallizers. This is important to ensure good spreadability when applying the fertilizer to the fields.

In the production of:

• Caprolactam (CPL) → Polyamide 6 (textile fiber, film)
• Acrylonitrile (AN) → Acrylamide, glue, solvent
• Methyl methacrylate (MMA) → Acrylic glass (Plexiglas)

Process: Ammonium sulphate as a by-product in the production of caprolactam

Synthetic production

Synthetically, ammonium sulfate is obtained by reacting gaseous ammonia and sulfuric acid. In this application, too, the processing of „waste sulfuric acid“ from production processes is more the reason for building ammonium sulfate plants than the global demand for ammonium sulfate. Due to unavoidable dissipative processes during the fast reaction, the product from reaction crystallizers is significantly finer and therefore cheaper than the higher quality product from DTB crystallizers.

Process: Synthetic production of ammonium sulphate

Desulfurization of coke oven gas

A comparable process for avoiding sulfur waste is also used in the purification of coke oven gas. Flue gas desulfurization produces ammonium sulfate as a byproduct.

Process: Recovery of ammonium sulphate from coke oven gas

Regardless of the process, the ammonium sulfate produced is usually further purified and dried to remove impurities and produce a high quality end product. The crystals can then be processed into granules or powders for use in various other applications.

Why are centrifuges important in ammonium sulfate processing?

Centrifuges are used in the processing of ammonium sulfate to remove excess liquid such as sulfuric acid and other impurities by washing them out of the ammonium sulfate crystals. For economic reasons, solid-liquid separation is mainly performed with filter pusher centrifuges and CONTURBEX centrifuges.