46 lines
1.8 KiB
Markdown
46 lines
1.8 KiB
Markdown
## Ammonium nitrate
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**Formula**
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$NH4NO3$
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**Pyrotechnic use**
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Oxidiser
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**Synonyms**
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ammonia nitre
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**Description**
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Ammonium nitrate is an oxidiser. It is very hygroscopic and therefore not used
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very often in fireworks. It finds some use in composite propellants, but
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performance is not as good as perchlorate-based propellants.
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**Sources**
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Ammonium nitrate solution can be prepared by neutralising ammonia solution with
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nitric acid. It is advised to use a slight excess of ammonia. That is to make
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sure no remaining acid will be present in the ammonium nitrate obtained on
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evaporation and crystallisation. Otherwise traces of the acid solution may be
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enclosed in the crystals, possibly leading to spontaneous ignition of mixtures
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made with it. Large quantities of ammonium nitrate can also be cheaply bought
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as fertilizer. ammonium nitrate can be extracted from ferilizer with water
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leaving the ammonium sulfate(solid) behind. Ammonium nitrate can also be found
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as the active agent in instant cold packs.
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**Hazards**
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Large masses of ammonium nitrate have been known to explode on some occasions
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although it is very insensitive. Smaller quantities are less likely to
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detonate. The risk of detonation increases when ammonium nitrate is molten or
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mixed with fuels such as metal powders or organic substances. Ammonium nitrate
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should never be mixed with chlorates as this may result in ammonium chlorate
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formation, possibly leading to spontaneous ignition. Mixtures of metal powders
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and ammonium nitrate are likely to heat up spontaneously and may ignite,
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especially when moist. This can sometimes be prevented by the addition of small
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amounts of boric acid (1 to 2%), but in general it is better to avoid these
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mixtures at all. The hygroscopic nature of ammonium nitrates makes this problem
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worse (also see aluminium). Toxicity: Oral rat LD50: 2217 mg/kg
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