Ammonium Nitrate (AN) is a colourless crystalline substance with the chemical formula NH4NO3 that is produced by combining nitric acid and ammonia. It is highly soluble in water and soluble in alcohol and liquid ammonia. Ammonium Nitrate reacts with combustible and reducing materials as it is a strong oxidant. It is widely used in fertilizers and explosives.
Urea Ammonium Nitrate (UAN) is a colourless, odourless liquid with a chemical formula (NH2)2CONH4NO3 that is produced by combining urea, nitric acid and ammonia. It is miscible in water and contains 32% nitrogen. The UAN solution is also known as UAN 32% solution and its composition (by % weight) is: 44.6% Ammonium Nitrate, 35.2% Urea and 20.2% water.
There is one Ammonium Nitrate plant and UAN plant located on the Point Lisas Industrial Estate. Both are produced in Methanol Holdings Trinidad Limited A-U-M Complex where the ammonium nitrate plant has a production capacity of 1905 metric tonnes (MT) per day of AN and the UAN has a production capacity of 4300 MT per day of UAN. The A-U-M complex was commissioned in 2010
Ammonium Nitrate and Urea Ammonium Nitrate are produced using the Uhde process technology from Germany. The UAN production process is briefly described in the flow chart.
The production process starts with nitric acid (HNO3) heating and ammonia (NH3) evaporation. In the Uhde reactor, the gaseous ammonia and aqueous nitric acid are combined in an exothermic neutralization reaction to produce an intermediate, ammonium nitrate (NH4NO3):
NH3 +HNO3 → NH4NO3
The vapour from the reaction is separated and then condensed. The remaining colourless liquid ammonium nitrate is used as an intermediate and is then mixed with urea to form UAN 32% solution which is then stored.
NH4NO3 + (NH2)2CO → (NH2)2CONH4NO3
Urea Ammonium Nitrate is a liquid fertilizer which is characterized by its high nitrogen content. Solutions of UAN are extremely versatile as a source of plant nutrition. Due to its chemical properties, UAN is compatible with many other nutrients and agricultural chemicals, and is frequently mixed with solutions containing phosphorus, potassium, and other essential plant nutrients. UAN Solution can be used on just about all crops. It is widely used for side-dressing cotton, vegetables, corn, beets, potatoes and other crops. UAN is superior for use with crops compared to ammonium nitrate, because it is a liquid at room temperature and can be mixed with other solutions such as pesticides for a single application to crops.
The hazards of UAN are eye and skin irritant. A typical Material Safety Data Sheet (MSDS) for UAN can be found at the link given below: