UAN
Template:Short description Template:Otheruses 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) 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 Template:Convert 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.
Physical and chemical characteristics of urea ammonium nitrate solutionsEdit
The solutions contain a remarkably low amount of water and nevertheless have a low salt-out temperature:
| Grade, N% | 28 | 30 | 32 |
|---|---|---|---|
| Ammonium nitrate (%): | 40 | 42 | 45 |
| Urea (%): | 30 | 33 | 35 |
| Water (%): | 30 | 25 | 20 |
| Specific gravity at 16 °C: | 1.283 | 1.303 | 1.320 |
| Salt-out temperature (°C): | -18 | -10 | -2 |
ReferencesEdit
- UNIDO and International Fertilizer Development Center (1998), Fertilizer Manual, Kluwer Academic Publishers, Template:ISBN.
- Simplot UAN-32 Product Data Sheet
- Poole Chemical UAN 32% Solution
- Tom Dorn, Extension Educator, Nitrogen Sources University of Nebraska Fact Sheet 288-01