papaya
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What was that?
Don't know if the question deserved a whole new thread, however I saw this on youtube: https://www.youtube.com/watch?v=TJ-g6dy06o8
and want to ask if anyone knows what kind of catalyst does that wonderful trick ?
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chemcam
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I have seen that before as ammonium nitrate and sugar intimitely mixed in water then dried.
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papaya
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Author states in the comment, that there's NO fuel at all - only catalyst, however doesn't specify what kind of. Btw. I see there a black border line
on the reaction front, may be some CuO (guessing), however AN itself is not blue colored, then what?
I've heard that chlorides accelerate decomposition rate of AN - can a simple table salt work here (I have no access to this http://pubs.acs.org/doi/abs/10.1021/ja01040a011
article, which seems interesting to have)?
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chemcam
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Oh I didn't bother to translate from Russian I guess I should have but when it is started by fire it makes me think there is fuel. But it is only
activated by fire(heat) then it decomps to smoke and what.. carbon or an oxide? Still seems like there is a fuel. Oh and I have seen blueish AN
before.
I don't have access to that article either sorry. I do want to know what this is also.
[Edited on 5-25-2013 by chemcam]
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papaya
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Well, fuel is not always necessary if the decomposition reaction is exothermic (this case). But even this in mind ordinary AN will not ignite, in
small quantities at least, since reaction is not very fast and heat is lost to surroundings - this is why catalyst is needed. Also the exact reaction
is impossible to point out, since the thing is very complex. And by no means CuO can be a fuel, it was just my guess since there's strange black
color.
I find this just wonderful, since AN hardly ignites even with fuels unless to say alone! Brave ideas?
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chemcam
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Whoops, didn't mean to say CuO was fuel. I was oblivious to the O even when I typed it.
[Edited on 5-25-2013 by chemcam]
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adamsium
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According to the paper, they used some different metal salts (nitrates, sulfates and carbonates and, and dichromate for chromium) along with sodium
chloride (in addition to the metal salt). Chromium seemed to give the 'best' result - hottest temperature (~350 C) and the shortest time, with all
ammonium nitrate consumed (copper was very similar to chromium). That said, the decomposition still took in excess of 80 min with chromium.
The authors used the following mixes: "ammonium nitrate, 75 mmoles (6 g); sodium chloride, 3.75 mmoles; and metal ion, 0.10 mmole. For most metals
this gives a concentration of about 0.1 wt %"... in a tube furnace at 185 C and sparged with dry nitrogen for the initial part (the sparging had to be
terminated early in the case of chromium due to the violence of the reaction). "Copious evolution of brown NO₂ fumes" was also observed toward
the end of the violent reaction with chromium salts.
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chemcam
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Well why don't we get a list going of possible catalysts then I will perform the tests and film it. I have quite a collection of reagents so I'm sure
I'll have what we need.
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papaya
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Thank you adamsium, ammonium dichromate indeed burns itself, and if it'll co-precipitate with AN from solution then this may be solution.
Does anyone have information on the mechanism of chloride ion catalysis ?
EDIT: Chemcam, You could try to co-precipitate dichromate + nitrate from hot solution (catalyst being some 5%), or even just mix powders of AN+AD
(+NH4CL or NaCL optionally). Another interesting test will be AN+metal oxides (Cr2O3, MnO2, Fe2O3, CuO) and the same with addition of say 1% NaCL
[Edited on 26-5-2013 by papaya]
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Bot0nist
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On the chloride catalyst issue. I was reading about "negative X" (really k3wl name...) on united nuclear, and they attempted to explain the
mechanisms. Negative X is a mixes of ammonia nitrate, ammonia chloride, and fine zinc powder. This mix is unstable, and ignited in damp air, or with a
drop of water do to an auto-catalytic effect. Pretty neat demo for the kids. Just don't add the zinc till use, and never store the mix, of course.
Sorry for OT.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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papaya
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Doesn't that work with NH4CL alone ? I suppose chloride is there to give complex with Zn and take it into solution, btw classical Zn-carbon batteries
use NH4CL as an electrolyte. What I mean - this may be not related to AN catalytic decomposition.
[Edited on 26-5-2013 by papaya]
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Bot0nist
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The NH4NO3 in the "negative X" composition is the source of the N2O, or was it NO2.., according to united nuclear's page on the mix. The mixture also
contians a large amount of AN, and only a small catalytic amount of ammonium chloride.
Google
negative X united nuclear fire
[Edited on 26-5-2013 by Bot0nist]
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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papaya
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This also is interesting https://www.youtube.com/watch?v=N6yqwzgowts
Does anyone know a fuel that will burn reliably with AN under normal pressure and in diameters about 3-5mm (NOT metals and not very hygroscopic)? What
about K4Fe(CN6), or maybe starch or anything else ?
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jock88
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Charcoal.
Look up Ammonpulver
http://forum1.aimoo.com/cast___boolits__/Special-Projects/Am...
Also see COPAE
[Edited on 12-6-2013 by jock88]
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papaya
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Charcoal will not burn with AN under normal pressure (in the barrel might), didn't try myself but have heard many times.
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plante1999
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"I remember seeing a post a while back where some user showed a video where ammonium nitrate analytically decomposed and asked what was the catalyst.
After some test and research, I found that a mixture of potassium ferrocyanide and potassium dichromate will catalyze ammonium dichromate
decomposition. A pinch of the two salts mixed with 10 g of ammonium nitrate make a suitable mixture. The ammonium nitrate is fairly easy to ligth and
will burn ferously leaving a green glass. It will make a lot of fumes that readily disperse, maybe because they are mostly water vapors.
A very impressive demonstration. If mixed with carbon, as in the original ammonpulver black powder, it may be possible to attain much faster burning
rate then what we observe when testing the original 85 ammonium nitrate 15 carbon ratio. "
Yes, I mean ammonium nitrate, it was wrote fast due to personal time limit.
I have no intent in advancing anymore the research to be honest. I only found out the answer to the question. I do think there is a huge gap of useful
concentration of catalyst and not a particular ratio, it is a catalyzed reaction. More catalyst means faster reaction but faster deterioration of the
reaction (buildup of in fusible catalyst front on the ammonium nitrate). Lighter amount of catalyst make the mixture harder to ignite.
Ferricyanide could indeed be used as it is the effective oxidizing agent in the mixture, the strongly oxidizing molten ammonium nitrate oxidize the
ferrocyanide to ferricyanide and potassium salts.
I believe each alone work, the dichromate is much better tough, but together they are far more efficient. I tried the said mix with dry mixing, in
solution the burn rate would even be greater due to the much better contact. Like I said, I must have used 0.1g of each for 10g of ammonium nitrate.
Ferrocyanide can't be considered as a fuel in such a situation. The effective catalyst is chromite, which is made by the alkaline reaction of chromium
oxide and iron oxide, all are made in the condition.
I never asked for this.
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papaya
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Thank You for answering plante
Quote: Originally posted by plante1999  |
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The effective catalyst is chromite, which is made by the alkaline reaction of chromium oxide and iron oxide, all are made in the condition.
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Is the mixed catalyst you used mentioned somewhere or you just found it out yourself(because chromite part is not obvious to me)? Anyway, nice find!
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papaya
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Hah, what a coincidence!
https://www.youtube.com/watch?v=9e8ICfx4JPI
this video is only two days old, it says that the catalyst used was dichromate / ferricyanide mixture! And how people just pick up a right recipe
remains a mystery to me..
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plante1999
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We might have stumbled upon the same reference for the catalyst mixture...
Don't have much time to explain more the concept, but try it, it works.
I never asked for this.
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papaya
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Yes, I tried already, but the AN was not crumbled well and the mixture was rough, so it didn't want to light up easily, only few instances it showed
self sustaining reaction and a lot of smoke. I used ammonium dichromate + potassium ferricyanide + AN (random amounts), but what I see in the last
video has a great potential, never seen anything based on AN to burn so vigorously, and if some fuel is added it might become something practically
useful (rockets?). What if ferricyanide is taken in excess(though expensive) that will serve as a fuel and bring the ratio to stoichiometric ?
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Fantasma4500
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hah.. i was actually gonna ask ADpirotek about it if nobody found the answer about it (:
as of what i know hes adminning a russian forum, somewhat alike SM, just alot more pyro-oriented
quality videos..
but i suppose as if this is catalysing the simple decomposition, would this mean this would be H2O + N2O decomposition, and would this be useful for
decreasing initiation energy for AN based binaries?? it should, shouldnt it? perhaps chemistry is different under such circumstances, or doesnt work
to catalyse it into other products than just low temperature decomposition
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Fantasma4500
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i have another thing..
approx 0.03g ammonium dichromate was mixed with approx 1g NH4NO3 99.9%
it was then attempted to ignite, definately catalytic effect, as it somewhat boiled without much heat added to it; not self sustaining
approx 0.05g +400mesh Mg dust was added
it was attempted to be lit again, without much luck but only once
at one time it flamed up or well made a little deflagration if you could call it that, but not self sustaining at all
after being amazed over the amount of smoke it gave off i decided to drag the smoke to my face to smell what the hell it was
a very sweet and weak concentration of NOx, probably NO2 was smelt
this wouldnt be something you would like to inhale, if you were expecting N2O (:
ill try decomposing it some more with ammonia next to it, should give some results
NH4NO2 is clearly smelt, and a dense descending cloud of NH4NO2 has been created
most definately there is NO2 in this, although not enough to colour the smoke visibly, perhaps if this smoke was put in a flask etc?
this could be one way to get a decent and easy amount of NO2 if the heat wouldnt be a problem and if the reaction could be controlled
what i guess the ferrocyanide would do would be acting as fuel
this is just a guess, i didnt use ferrocyanide, correct me if im wrong, but i did see increase in the reaction when i added Mg although there was no
sparks whatsoever
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papaya
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To my knowledge both catalyst must be used together for this effect. Look for adpirotek's other videos, where he ignites AN+charcoal(+dichromate) and
it burns very quietly, though I don't know how ferricyanide alone will work. And no, from what I read catalyst don't influence detonation properties
(only serve as a ballast), perhaps they're too slow for that.
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