Calcium nitrate, also called Norgessalpeter (Norwegian saltpeter) is the inorganic compound with the formula Ca(NO₃)₂. This colourless salt absorbs moisture from the air and is commonly found as a tetrahydrate. It is mainly used as a component in fertilizers. Nitrocalcite is the name for a mineral which is a hydrated calcium nitrate that forms as an efflorescence where manure contacts concrete or limestone in a dry environment as in stables or caverns.

Production and reactivity

Norgessalpeter was the first nitrogen fertilizer compound to be manufactured. Production began at Notodden, Norway in 1905. Most of the world's calcium nitrate is now made in Porsgrunn. It is produced by treating limestone with nitric acid, followed by neutralization with ammonia:

CaCO₃ + 2 HNO₃ → Ca(NO₃)₂ + CO₂ + H₂O

It is also a byproduct of the Odda Process for the extraction of calcium phosphate:

Ca₃(PO₄)₂ + 6 HNO₃ + 12 H₂O → 2 H₃PO₄ + 3 Ca(NO₃)₂ + 12 H₂O

Like related alkaline earth metal nitrates (as well as LiNO₃), calcium nitrate decomposes upon heating to release nitrogen dioxide:

2 Ca(NO₃)₂ → 2 CaO + 4 NO₂ + O₂ ΔH = 369 kJ/mol

Use in fertilizer

The fertilizer grade (15.5-0-0 + 19% Ca) is popular in the greenhouse and hydroponics trades; it contains ammonium nitrate and water, as the "double salt" 5Ca(NO₃)₂.NH₄NO₃^.10H₂O. Formulations lacking ammonia are also known: Ca(NO₃)₂.4H₂O (12.8-0-0 + 18.3%Ca). An anhydrous, air-stable derivative is the urea complex Ca(NO₃)₂^.4[OC(NH₂)₂].

References

External links

• Yara corporate history
• Calcium Nitrate - a Hydroculture Salt