Ammonium sulfate

Ammonium sulfate is a very useful inorganic salt. It is most often used as a fertilizer for farming. This salt is helpful for alkaline soils. It contains 21% nitrogen and 24% sulfur. These two parts are very important for plants. Nitrogen helps plants grow much better.

The salt also helps change the pH balance of the soil. It does this by releasing an ammonium ion. This ion creates a small amount of acid in the ground. This makes the soil better for certain crops. Some people also use it as a spray for farm chemicals. It helps bind iron and calcium in water and plant cells. This makes it a good partner for herbicides like glyphosate.

Scientists use this salt in many ways in the lab. One common way is a method called precipitation. This is a way to purify proteins. When you add the salt to a liquid, the protein becomes less soluble. Being soluble means it can dissolve easily. As the salt makes the liquid stronger, the proteins turn into solids. This is called "salting out." This process does not damage the proteins. Scientists can turn them back into a liquid later using buffers. This makes it a simple way to sort through complex mixtures.

There are several ways to make ammonium sulfate. One way is to treat ammonia with sulfuric acid. A reactor holds a solution of the salt and acid at 60 °C. Heat from the reaction keeps the temperature steady. You can also make a dry powder by spraying acid into ammonia gas. Another way uses a mineral called gypsum. Workers add fine gypsum to an ammonium carbonate solution. This causes calcium carbonate to turn into a solid. This leaves the ammonium sulfate in the liquid.

This salt has many different roles in our world. The U.S. Food and Drug Administration calls it safe to eat. In the European Union, it is known as food additive E517. It helps control acidity in bread and flour. It is also used in many vaccines in the United States. Some people use it as a flame retardant. This helps materials resist burning by increasing the heat needed for fire. In 1981, the world produced about 6,000 million tons of it.

Ammonium sulfate can be found in nature too. It appears in rare minerals called mascagnite. You might find it in volcanic fumaroles. It can also come from coal fires on some dumps. It is also a byproduct of making methyl methacrylate. However, some parts of the world have had to ban it. In 2009, the NWFP government in Pakistan banned certain fertilizers. They did this because militants used them to make explosives. Afghanistan also passed a ban in January 2010.