What is BIG N

BIG N ® is a highly concentrated nitrogen fertiliser. Its chemical name is anhydrous ammonia.

Anhydrous ammonia is a colourless, pungent gas at room temperature. It takes a liquid form under pressure and this is how it is delivered and stored.

Incitec Pivot Limited manufactures BIG N by direct synthesis of nitrogen from the air and hydrogen from natural gas.

Nitrogen makes up 82.25% of anhydrous ammonia, with hydrogen making up the remaining 17.75%. It is also known by its chemical symbol (NH₃).

Chemical facts and figures

• People can smell the sharp, intensely irritating odour of BIG N in the air even when it is at very low concentrations (0.6 ppm).
• BIG N condenses to become a colourless liquid at a pressure of about 900 kPa (131 PSI). At atmospheric pressure, it liquefies at -330°C.
• Liquid anhydrous ammonia expands when released to the atmosphere. One kilogram of BIG N will expand to fill 1.4 m³. 
• Dry ammonia is attracted to water and will absorb even traces of moisture. To prevent corrosion of BIG N equipment, copper, cadmium, zinc and their alloys  cannot be used in BIG N fittings.
• BIG N as a liquid can expand by as much as 8% with rising temperatures. Space should always be left in tanks to account for this potential expansion. 
• BIG N is not aqueous ammonia. Aqueous ammonia (also called ammonia hydroxide, liquid ammonia or aqua ammonia) is a solution of ammonia in water.