UAN 32% Storage — High-Density Liquid N Tank Specification

Storing Urea Ammonium Nitrate 32? Start Here

If you're dealing with Urea Ammonium Nitrate 32% (UAN 32), you're handling the highest nitrogen density liquid fertilizer commonly used in fields. It's a powerful tool for delivering nitrogen, but it comes with its own storage challenges. The key is understanding the behavior of UAN 32, especially its tendency to "salt out" or crystallize at temperatures below 32°F (0°C). This makes winter storage a critical consideration, especially in colder climates.

Can you store it in a poly tank?

Yes, you can store UAN 32 in a polyethylene tank. High-density polyethylene (HDPE) or cross-linked polyethylene (XLPE) tanks rated at 1.4 ASTM specific gravity are suitable. Ensure your tank has EPDM gaskets and 316 stainless steel bolts to handle the chemical's properties effectively.

Watch out for freezing temperatures

The biggest issue with UAN 32 is its salt-out point at 32°F. In regions with freezing temperatures, you need to invest in winter-management systems like heat tracing, tank-blanket heaters, and insulation jackets to prevent crystallization and maintain the solution's integrity.

The safety that actually matters

• Ensure your tank is rated for the specific gravity of UAN 32.
• Use EPDM gaskets to prevent chemical reactions that could lead to leaks.
• Implement a winter-management system if your area experiences freezing temperatures.
• Maintain proper fill-point hygiene to avoid contamination.
• Use atmospheric venting to manage low vapor pressure safely.

Common questions

What happens if UAN 32 freezes?

If UAN 32 freezes, it can crystallize and separate, making it difficult to use effectively. Proper insulation and heating can prevent this.

Can I use Viton gaskets with UAN 32?

No, Viton gaskets swell under urea service. Use EPDM gaskets instead.

Do I need special fittings for UAN 32 tanks?

Yes, use polypropylene or PVC fittings. Avoid glass-filled nylon as they may fail under thermal cycling.