UAN is a solution of urea and ammonium nitrate in water used as a fertilizer. The combination of urea and ammonium nitrate has an extremely low critical relative humidity (18% at 30 °C) and can therefore only be used in liquid fertilizers. The most commonly used grade of these fertilizer solutions is UAN 32.0.0 (32%N) also known as UN32 or UN-32, which consists of 45% ammonium nitrate, 35% urea and only 20% water. Other grades are UAN 28, UAN 30 and UAN 18. The solutions are quite corrosive towards mild steel (up to 500 milliinches per year on C1010 steel) and are therefore generally equipped with a corrosion inhibitor to protect tanks, pipelines, nozzles, etc. Urea–ammonium nitrate solutions should not be combined with calcium ammonium nitrate (CAN-17) or other solutions prepared from calcium nitrate. A thick, milky-white insoluble precipitate forms that may plug nozzles and pipelines.
UAN is a solution of urea and ammonium nitrate in water used as a fertilizer.
Uan or UAN may also refer to:
- Adapa, an alternate name for the first of the Mesopotamian seven sages
- Autonomous University of Nayarit ((in Spanish: ), a Mexican public university based in the city of Tepic, Nayarit
- Kuan language (Laos), by ISO 639-3 language code
- United American Nurses, formerly an American union affiliated with the AFL-CIO
(National Academic Union), a learned society in Italy
- Universal Account Number, a 12-digit number allotted to employee who is contributing to the Employees' Provident Fund Organisation of India