Catalist for thermal decomposition of AN

[ikbendirk]

hi all.. i'm new on the forums here :D
i'm into explosives for about two years now...
i have read much about all kinds of bombs

but now i have a question about Ammonium Nitrate...
it is said to be an extreme insensitive material "...you can put it under your bed, and have more worries for your pillow to explode..."
but on safety cards, i've often read that in acidic enviroments (in addition of Cl, Fe, Co Ni, Cr, Zn or Cu) the 'thermal decomposition' is catalysed.

I was wondering what thermal decomposition they were talking about;

- NH4NO3 ---> N2O + 2H2O
- NH4NO3 ---> NH3 + HNO3
- NH4NO3 ---> N2 + 2 H2O + 1/2 O2

The last one is the Rxn of the detonation of AN.
If this is the reaction that is catalysed, the insensitivity of AN could be greatly reduced by adding common salts like NaCl, Fe2O3, CuSO4, etc.
this way it could be detonated a great deal easier, and it would be way more efficient to use :)

if the first of the above rxns occurs, its ok too, because my interest in AN started with the desire to make my own nitrous... if that could be possible by adding some ordinary NaCl... oh my :D

[EDIT:] oh and if this is the wrong forum to post please tell me :cool:

[Mr Cool]

"i have read much about all kinds of bombs"

Oh dear. That gives the impression of crapbook reading...

"in addition of Cl, Fe, Co Ni, Cr, Zn or Cu"

Ions, or elements?

Cl- (eg from NaCl) does catalyse AN's thermal decomposition to nitrous oxide and water in dilute acid.
Certain metal salts (transition metal oxosalts) will form energetic complexes with AN which do increase its sensitivity to initiation. I'm not at all sure about iron, but the rest in that list should.
Iron oxide is used as a catalyst in nitrate-based solid rocket fuels, but I'm not sure if it catalyses the decomposition of the nitrate or the fuel. So it might work, or it might not.
Some metal powders act as a fuel, and therefore sensitise AN and make it more powerful.

Read everything on this site about AN, then you'll have lots of info at your disposal.

I'll leave this open for now, something interesting might come of it. However, it might do better in a different forum, but I haven't worked out how to move topics with the new software...

[palpy]

Well, I can't tell you exactly what does work and what doesn't but the CuSO4 you mentioned can be a good choice, as copper salts form trace amounts TACN in AN mixtures. This TACN, being itself a sensitive HE, of course increases the sesitivity of the whole mixture.
And what's more, when not sure if your AN is perfectly dry, adding DEHYDRATED CuSO4 can also do the trick (it's more hygroscopic IIRC).

And IIRC dichromates can be used as catalysts in AN explosives...

PS: ALWAYS consider compatibility with other ingredients!

[kingspaz]

palpy, as for TACN being sensitive, any that formed under atmospheric conditions (water vapour in the air) would be th hydrated form - not sensitive or energetic enough to act as a primary. in my opinion anyway.

[Zeitgeist]

You'd certainly find out if there was any moisture present with the addition of anhydrous CuSO4, from the colour of the hydrated form forming

[Rosco Bodine]

It seems to be the premise that there is necessarily some relationship
between a thermal decomposition catalyst and a detonation catalyst .

There isn't necessarily any mutual relationship at all between the two .

[ikbendirk]

because there isn't necessarily a relation, i would like to know whích rxn is catalysed...

i don't know if ions or elements should be used, the row of catalyst was found on some safety data sheets, but they didn't specify... (perhaps both will do?)
im pretty sure the Cl in the list is about Cl- ions indeed, because i got confirmation about that on an other site.

im currently purifying some AN extracted from fertilizer, when they are ready i could test it.. (not quite sure about the det yet though :rolleyes: )

[Rosco Bodine]

Strontium nitrate , lead nitrate , copper nitrate , potassium nitrate ,
ammonium perchlorate and ammonium persulfate are all detonation catalysts
for AN . Urea , hexamine , and their nitrates work too . Organic peroxides
are also effective .

The only thing I recall about chlorine as a detonation catalyst was
using chlorinated hydrocarbons or nitrated chlorinated hydrocarbons .

[kingspaz]

could KClO3 have possibilities? if mixed right before use then it should be relatively safe from spontaneous decomposition with the AN...

[Bert]

could KClO3 have possibilities? if mixed right before use then it should be relatively safe from spontaneous decomposition with the AN...

If you'll check the boomershoot.org site "project nitro" section (http://www.boomershoot.org/general/Nitro.htm) you'll see an example of chlorate + AN sensitization- It's kind of annoying to read their mixes, as they insist on measuring by volume rather than weight, but you'll get at least an idea of the sensitivity of some various mixes.

[Zeitgeist]

I thought it went without saying, Ammonium salts and chlorates together is a bad idea

[Bert]

thought it went without saying, Ammonium salts and chlorates together is a bad idea

I certainly wouldn't store such a mix, nor damp it with water. However, these guys have made litteraly TONS of this over several years time, and had no accidents. BTW, there were commercial and military smoke mixes that contained chlorate and ammonium chloride.

[Jacks Complete]

If you'll check the boomershoot.org site "project nitro" section (http://www.boomershoot.org/general/Nitro.htm) you'll see an example of chlorate + AN sensitization- It's kind of annoying to read their mixes, as they insist on measuring by volume rather than weight, but you'll get at least an idea of the sensitivity of some various mixes.
Bert,
I would say I don't mind which way the mixes are quoted, as long as they state clearly which they are using! After all, careful weighing of AN mixes is a waste of time, since it isn't critical in the least, and for the much larger amounts, volume makes it far easier to use a scoop (for me, plastic drinks cups from the supermarket at ~1p each - or free with every drink of water!) as well as avoiding having to buy scales that are solely for use with sometimes noxious things that you don't really want in the kitchen.

[Guerilla]

I thought it went without saying, Ammonium salts and chlorates together is a bad idea For a pyrotechnic composition with a good shelf life yes, but for an exploding target that can be set off with a .22 LR you need sensitivity, and ammonium chlorate not only is sensitive but also functions as a primary. It is also said to be less prone to accidental detonation when mixed with other combustible materials.

According to this page (http://www.sfc.fr/Guiochon%20VO/decompositionVO.htm), Cl- ions catalyze the decomposition that yields HNO3, N2 and H2O.