Ammonium nitrate

This white salt is very useful. It helps plants grow strong. Farmers use it as food for crops.

It is also used to make big blasts. People use these blasts in mines. They use them to build things, too.

This salt can be dangerous. If it gets too hot, it can explode. This can hurt many people.

It can even be used in cold packs. When it hits water, it gets cold. This helps keep things cool.

We must be very careful with it. It stays safe when we store it right.

Ammonium nitrate is a white salt. It is a chemical compound. Many people use it every day. Farmers use it as a fertilizer. This helps crops grow with nitrogen. It is also used to make explosives. People use these for mining and building. One common type is called ANFO. It is a mix of this salt and fuel oil.

This salt can be dangerous. It is a strong oxidizer. This means it helps fires burn faster. If it gets very hot, it can explode. These explosions can hurt many people. Some big explosions happened in places like Beirut and Tianjin.

There are other ways to use it. It can be used in instant cold packs. When the salt hits water, it gets cold. This is because it takes in heat. It was even used in car airbags.

We must store it very carefully. It should stay in sealed containers. This keeps it dry. If it gets wet, it can turn into a big, hard mass. It must stay away from things that burn easily.

Ammonium nitrate is a white salt made of two parts: ammonium and nitrate. It is a very useful chemical for many different jobs. Farmers use it as a fertilizer to help crops grow with nitrogen. It is also used to make industrial explosives. These help people in mining, quarrying, and building large structures. Because it is so useful, the world makes huge amounts of it. In 2017, global production was about 21.6 million tonnes.

Making this salt is a very busy way of working. First, scientists react ammonia with nitric acid. This reaction is violent because it releases a lot of heat. This heat-releasing process is called an exothermic reaction. After the liquid is made, workers evaporate the extra water. This leaves a very strong concentration of the salt. Then, they turn the liquid into small beads called prills. They can also make granules by tumbling them in a rotating drum.

People have found ways to get this salt for a long time. In the past, it was mined from the Atacama Desert in Chile. It was found there as a natural mineral called gwihabaite. It often looked like a crust on the ground. Later, a new way called the Haber–Bosch process was invented. This made it possible to create nitrates from nitrogen in the air. Because of this, mining the mineral became unnecessary.

Ammonium nitrate can be very dangerous if it is not handled well. It is a strong oxidizer, which means it helps other things burn faster. If it gets very hot or is hit by a shock, it can explode. Large explosions have happened in many places. Some famous disasters include the Oppau explosion in 1921 and the Texas City disaster in 1947. There were also big explosions in Tianjin, China, in 2015 and Beirut in 2020.

Even though it can be dangerous, we use it in many small ways too. You might find it in instant cold packs. When the salt dissolves in water, it absorbs heat from its surroundings. This makes the pack feel very cold. Scientists in Saudi Arabia are even studying it for cooling systems. It was also used in car airbags to help them inflate. We must always store it in sealed containers to keep it dry.

Ammonium nitrate is a white crystalline salt with the chemical formula NH4NO3. It is composed of two specific ions: ammonium and nitrate. This compound is incredibly important in modern industry because it serves two very different roles. Primarily, it is used as a high-nitrogen fertilizer to help plants grow. Secondarily, it is a key ingredient in many industrial explosive mixtures. Because it can support combustion and release energy, it must be handled with extreme care.

Industrial production usually begins with an acid-base reaction. Workers combine ammonia (NH3) with nitric acid (HNO3) to create the salt. This specific chemical reaction is highly exothermic, meaning it releases a large amount of heat. Once the solution is formed, it typically reaches an 83% concentration. To increase this, the excess water is evaporated away. This process leaves a highly concentrated ammonium nitrate melt, ranging from 95% to 99.9% concentration. This melt is then processed into small beads called prills in a spray tower. Alternatively, it can be turned into granules by spraying and tumbling it in a rotating drum. These final products are often dried, cooled, and coated to prevent them from sticking together.

Ammonium nitrate exists in several different crystalline phases depending on the temperature. At room temperature, it often transitions between the beta-rhombic and alpha-rhombic forms. This transition happens at 32.3 °C. Because these two forms have a 3.6% difference in density, the material changes volume during the switch. This volume change can cause the solid to crack. For this reason, it cannot be used as a solid rocket motor propellant unless it is stabilized. Stabilized ammonium nitrate, or PSAN, uses metal halide stabilizers to prevent these density fluctuations.

Before modern chemistry, people had to mine ammonium nitrate from the earth. It occurs naturally as a mineral called gwihabaite in the Atacama Desert in Chile. In those extremely dry regions, it often appears as a crust on the ground. However, the invention of the Haber-Bosch process changed everything. This process allows scientists to synthesize nitrates from nitrogen in the atmosphere. As a result, mining the natural mineral became obsolete. Today, the world produces millions of tonnes of the synthetic version every year. Global production was estimated at 21.6 million tonnes in 2017, though it dropped to 16.7 million tonnes by 2021.

In agriculture, ammonium nitrate is a vital tool for food production. It has an NPK rating of 34-0-0, meaning it contains 34% nitrogen. While urea has a higher nitrogen concentration at 46%, ammonium nitrate is more stable. It does not lose its nitrogen to the atmosphere as quickly. In the mining and construction industries, it is used as a powerful explosive. A common example is ANFO, which is a mixture of 94% ammonium nitrate and 6% fuel oil. ANFO is widely used in coal mining and quarrying because it is inexpensive and easy to use. It accounts for 80% of the explosives used in North America.

Despite its uses, ammonium nitrate poses significant safety risks. It is a strong oxidizer, which means it helps other materials burn more intensely. If the salt is heated, it undergoes decomposition. At temperatures below 300 °C, it produces nitrous oxide and water. At higher temperatures, it decomposes into nitrogen, oxygen, and water. These reactions are also exothermic. If the decomposition happens too quickly, it can lead to a runaway reaction and an explosion. Large-scale disasters have occurred due to these risks. Notable examples include the Oppau explosion in 1921 and the Texas City disaster in 1947. More recently, massive explosions occurred in Tianjin, China, in 2015 and Beirut in 2020.

Beyond heavy industry, ammonium nitrate has several niche applications. It is used in instant cold packs because its dissolution in water is highly endothermic. This means it absorbs heat from its surroundings, making the pack feel cold. Scientists at King Abdullah University of Science and Technology are researching its use for off-grid cooling systems. It was also previously used as a cheaper component in car airbags. However, some versions were found to be unstable, leading to major recalls. Because of its potential for misuse, many countries have implemented strict regulations and licensing requirements for its sale.