Calcium ammonium nitrate

Calcium ammonium nitrate or CAN, also known as nitro-limestone, is a widely used inorganic fertilizer, accounting for 4% of all nitrogen fertilizer used worldwide in 2007.[1]

Production

Calcium ammonium nitrate is made by adding calcium carbonate to a slurry of ammonium nitrate,[1][2] resulting in a mixture of calcium nitrate and residual ammonium nitrate. It crystallizes as a hydrated double salt: 5Ca(NO3)2•NH4NO3•10H2O.

Consumption of CAN was 3.54 million tonnes in 1973/74, 4.45 million tonnes in 1983/84, 3.58 million tonnes in 1993/94.[3] Production of calcium ammonium nitrate consumed 3% of world ammonia production in 2003.[3]

Physical and Chemical Properties

Calcium ammonium nitrate is hygroscopic. Its dissolution in water is endothermic, leading to its use in some instant cold packs.

Use

Most calcium ammonium nitrate is used as a chemical fertilizer. Fertilizer grade CAN contains roughly 8% calcium and 21-27% nitrogen.[4] CAN is preferred for use on acid soils,[3] as it acidifies soil less than many common nitrogen fertilizers [4] It is also used in place of ammonium nitrate where ammonium nitrate is banned.[2]

Calcium ammonium nitrate is used in some instant cold packs as an alternative to ammonium nitrate.

Calcium ammonium nitrate has seen increasing use in improvised explosives. CAN and other chemical fertilizers were banned in the Malakand Division and in Afghanistan following reports of its use by militants to make explosives.[5]

References

  1. ↑ 1.0 1.1 Smil, Vaclav. Enriching the Earth. Massachusetts Institute of Technology. p. 135.
  2. ↑ 2.0 2.1 United Nations Industrial Development Organization (1998). Fertilizer Manual. Netherlands: Kluwer Academic.
  3. ↑ 3.0 3.1 3.2 Maxwell, Gary R. (2004). Synthetic Nitrogen Products. Kluwer Academic.
  4. ↑ 4.0 4.1 Australian Soil Fertility Manual. Fertilizer Industry Federation of Australia. 2006.
  5. ↑ Brummit, Chris. "Pakistani fertilizer fuels Afghan bombs, US troop deaths". NBC. Retrieved 3 May 2013.