What product is released in a ammonium nitrate explosion?

[Legoman2179]

I am wondering what is released in an ammonium nitrate explosion.

Ammonium Nitrate = NH4NO3

[MigL]

Ammonium Nitrate is not explosive.

It is an oxidizer,and only explosive when combined with reducing fuel.

 

It is usually used as a fertilizer.

And I hardly ever see seedlings blowing up.

Edited March 3, 2016 by MigL

[John Cuthber]

Ammonium Nitrate is not explosive.

It is an oxidizer,and only explosive when combined with reducing fuel.

 

It is usually used as a fertilizer.

And I hardly ever see seedlings blowing up.

Guess again

https://en.wikipedia.org/wiki/Ammonium_nitrate_disasters

OK, strictly speaking, there needs to be some sort of impurity, but it's still largely the decomposition of ammonium nitrate that does the damage.

[Elite Engineer]

Ammonium Nitrate is not explosive.

It is an oxidizer,and only explosive when combined with reducing fuel.

 

It is usually used as a fertilizer.

And I hardly ever see seedlings blowing up.

You haven't lived till you've seen a seedling blow up

[Enthalpy]

Ammonium nitrate detonates without any fuel, but then it needs a detonator. Varied impurities make it much more sensitive and capable to detonate from heat without a blast cap; then the spoiled part serves as the detonator to the rest of the ammonium nitrate.

 

I've run Propep on it at arbitrary 10,000 bar, here are the main molar fractions:

H₂O 0.57

N₂ 0.29

O₂ 0.14

HNO₃ 1ppm

OH, NO₂, N₂O nothing

 

but at 100bar no HNO₃ is formed, the rest stays as is.

In both cases, the temperature is only 1245K.

[SergUpstart]

On 3/4/2016 at 12:59 AM, MigL said:

Ammonium Nitrate is not explosive.

It is an oxidizer,and only explosive when combined with reducing fuel.

This is an oxidizer and reducing agent in one bottle. The NH3 reducing agent HNO3 is the oxidizing agent.

But in order for ammonium nitrate to detonate, it must be cleaned of water (it is very hygroscopic) and properly compacted.

Edited July 30, 2020 by SergUpstart

[MigL]

From Wiki

"Ammonium nitrate is not an explosive in the form it is commonly sold.^[10] However it readily forms explosive mixtures with varying properties when combined with primary explosives such as azides or with fuels such as aluminium powder or fuel oil."

https://en.wikipedia.org/wiki/Ammonium_nitrate

As to the violent decomposition when quickly heated, I can also make a balloon full of air explode, by heating it.
And just to be clear, once you add heat to decompose it to anhydrous ammonia and nitric acid ( which are not the decomposition products, by the way ), it is the combination of ammonia ( strong reducer ) and nitric acid ( strong oxidizer ) that is explosive, not the original ammonium nitrate.

Edited July 30, 2020 by MigL

[Enthalpy]

Ammonium nitrate can detonate without a fuel. This is perfectly known. My source is a book is two thick volumes that deals only with explosives. But Wiki tells it too:
"While ammonium nitrate is stable at ambient temperature and pressure under many conditions, it may detonate from a strong initiation charge. It should not be stored near high explosives or blasting agents."
https://en.wikipedia.org/wiki/Ammonium_nitrate

Starting a detonation in ammonium nitrate is uneasy, but a local part tainted with some fuel suffices. The molecule undergoes detonation, that is, propagation of the decomposition by the shock wave rather than by heat, without passing by ammonia and nitric acid.

==========

The products released are not quite clear to me. In the detonation itself, the Propep software finds exclusively N₂, H₂0, O₂.
The molar composition after expansion from 1 000 bar or 10 000 bar is:
0.46 H₂O
0.29 N₂
0.14 O₂
0.12 H₂O liquid
Zilch, nada, niente -> Everything else, including N₂O, NO, NO₂

Though, some powder is dispersed without detonation, which might provide other decomposition products making the NO₂ colour seen at Beirut. Red smoke was reported over an other ammonium nitrate explosion, I wish I saw colour pictures.

==========

Video of the damage in Beirut by the explosion of 4 August 2020
https://www.youtube.com/watch?v=FMvBg7YIDAA
impressive damage, impressive pilot skills.

==========

If ammonium nitrate in thousands of tons were stored at Beirut's port, inevitably some Lebanese faction used it to make bombs.

In the morning of 4 August 2020 before 11h CET (9h UT), a small dozen of big four-propellers military cargo planes flew over my home near Ramstein (US base in Germany). About as many flew (back?) spread over the 5 and 6 of August. That's usual before military operations.

Several countries have developed laser weapons. The US demonstrated (and abandoned) a jumbojet-sized one to destroy missiles 500km away, and more recently smaller lasers to destroy at less distance a drone approaching a ship. Because igniting a fire is much easier than destroying a missile, inevitably these lasers serve for arson too. Accountability would justify the heavy means despite one missile from one combat plane would obtain the same result.

Less expectedly, the French secret services tell me to shut up about this, rather than the US ones.