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Ammonium Sulfate

Nitrogen fertilizer with proven performance

Ammonium sulphate nitrogen fertilizer crystals in bags for fertilizing plants

Ammonium Sulfate ((NH₄)₂SO₄) is a product manufactured on a large scale and used mainly as a nitrogen fertilizer in agriculture. In addition, there are numerous other niche applications, e.g. as a food additive and in drinking water treatment.

What is Ammonium Sulfate used for?


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.

Tractor on a green field. Ammonium sulphate fertilizer is being spread.
Various types of bread and rolls. Ammonium sulphate is used, among other things, as an acidity regulator in flours and breads
Water treatment plant
Ammonium sulphate nitrogen fertilizer. Granules are applied to the soil under a young plant

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)

Prozessschema: Gewinnung von Ammoniumsulfat als Nebenprodukt bei der Herstellung von 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.

Prozessbeispiel: Synthetische Herstellung von Ammoniumsulfat

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.

Prozess: Gewinnung von Ammoniumsulfat bei der Rauchgasentschwefelung

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.

SHS pusher centrifuge in fertilizer production
Pusher centrifuge SHS for monosodium glutamate
Interior view of a pusher centrifuge SHS with ammonium sulphate as product
12 sieve screw centrifuges type CONTURBEX H in a plant for Potash

Wear Protection

SIEBTECHNIK TEMA centrifuges are specially optimized for the respective separation task. When selecting materials, austenitic and ferritic stainless steels have proven themselves in centrifuge construction for applications subject to normal stresses.

For processes in which abrasive materials are processed, the centrifuges must be provided with effective wear protection. Starting with hard coal processing, we have been continuously developing wear protection systems since 1922.

Our centrifuges can be equipped with highly developed wear protection systems made of e.g. tungsten carbide, Stellite® or ceramic tiles, to name but a few. Rubber coatings or matrix coatings have also proven themselves in various applications.

If required, our engineers develop new and efficient solutions in coating, bonding and joining technology for our customers worldwide.

Centrifuge Components Materials

Centrifuge components must not only withstand high forces, but also process-related stresses such as corrosion, wear and high temperatures. Cost and availability of materials also play an important role. Our customers select the necessary product-contacting materials according to these very specific requirements.

Duplex and high-alloy stainless steels, Hastelloy® and titanium materials for a wide variety of processes and stresses are part of our daily business in centrifuge construction. Our quality management has developed very detailed and cost effective processes for design, manufacturing processes and component testing based on European guidelines.

Typical sheet metal and forging materials for centrifuge wetted components include

  • EN 1.4404 / AISI 316L
  • EN 1.4571 / AISI 316Ti
  • EN 1.4462 / AISI 318LN / Duplex
  • EN 1.4410 / AISI F53 / Super Duplex
  • Lean Duplex
  • EN 1.4539 / AISI 904L
  • EN 1.4547 / 254SMO®
  • EN 1.4529 / AISI 926
  • EN 2.4819 / INCONEL® Alloy C-276
  • EN 2.4602 / Hastelloy® C22
  • EN 2.4610 / Hastelloy® C4
  • EN 3.7035 / Ti-II / Titan 994-Ti-grade 2
  • EN 3.7235 / Ti-IIPd / Titan 994 Pd-Ti-grade 7
  • and their casting materials
SIEBTECHNIK sieve screw centrifuge CONTURBEX H700 for lactose - hall view with several machines

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SHS pusher centrifuge in fertilizer production

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CONFLUX tumbler screening machine in a technical center

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