Sciencemadness Discussion Board - Mixing Chlorates With Ammonium Compounds

Mixing Chlorates With Ammonium Compounds

jpsmith123 - 20-12-2005 at 03:55

One of the first things I learned about chemistry was to never mix a chlorate with an ammonium compound, lest I end up with the dangerously unstable ammonium chlorate.

I recently came across a patent (US 3282753) for a commercial blasting agent where the inventor apparently suggests doing exactly that; in this case he mixes sodium chlorate and ammonium nitrate (example 1 and 2 on the second page).

My first thought was that the inventor simply may not have known what he was doing, but the inventor in this case is Melvin A. Cook, founder of IRECO, and supposedly an expert, especially in the area of slurry explosives.

I wonder, what's going on here? Was the danger posed by ammonium chlorate not known or appreciated in 1964, or does Melvin Cook know something many other people don't, or did he just make a mistake?

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Marvin - 20-12-2005 at 09:06

Difficult to tell. Ammonium compounds and chlorates can produce sensitive mixtures but for maximum danger ammonium chlorate must be formed itself as a solid.

Not all combinations of ammonium compounds and chlorates can produce ammonium chlorate, its usually dependant on precipitation of the left overs first to leave an ammonium chlorate mixture which then dries out or dissolves more chlorates and ammonium salts.

In this case we have a slurry, kept from going acid and never intended to dry out. Prior to any scaling up they would have had to do aging tests that would make sure the mix was safe to store, maybe these failed and it never ended up as a licenced product. Suggesting a 160g booster for detonation does not take it far out of the ANFO catagory it started in anyway, and ANFO can be made on site for most quarry purposes so maybe it passed and just wasn't worth it.

PHILOU Zrealone - 20-12-2005 at 09:17

1°) A lot of water, and solvents
2°) Tiny percentage of the oxydiser is dissolved.
3°) Stabilised by carbonates and hydroxydes...to prevent decomposition of ClO3(-)...
It seems thus the decomposition of NH4ClO3 is reduced by the presence of 1% base...
KOH + NaNO3 --> KNO3 + NaOH
KOH + NH4NO3 --> NH3 + KNO3
KOH + NH4ClO3 --> NH3 + H2O + KClO3
So the real stabilisation seems to come from NH3 itself...

This would imply that first theory I had about decomposition of NH4ClO3 to come from the acid catalysed decomposition into NCl3 is (at least partially) true

!

It is wel known that NH4(+) can be oxydised by Cl2 into NCl3 under acidic conditions...NH4(+) in water is a mild acid...
1% NH3 remains easily in solution...thus no bubbles formed.

markgollum - 20-12-2005 at 14:08

Regarding the sensitivity of chlorate/ ammonium nitrate mixtures.

Last year I did an experiment with a charge that consisted of
ammonium nitrate and KClO3.

As I remember, I used model airplane fuel containing 35% nitromethane 45% methanol and 20% oil.
The composition of the charge was decided by calculating how much NH4NO3 was needed to completely combust the nitromethane in the fuel, and how much KClO3 was needed to completely combust the methanol.

I first made a small amount of this mixture ~1g.
.3g was heated strongly with a propane torch until only molten KCl remained (no energetic reaction).
~.1g was placed on an iron anvil and struck with a framers hammer, it only splattered. 10 min later after some of the solvents had evaporated, the experiment was repeated with the same result until only ~.2g remained .
Several hours later, once all the NM and MeOH had evaporated, that ~.2g was struck violently with the hammer with no explosion.

The next day I transported enough of the three ingredients to the blast site seperatly for a total charge wheight of 60g.
The ingredients were added to a small glass jar and thoroughly mixed. The jar was placed in a deep hole on top of an old circular piece of steel from a disking machine and initated with 1.5g HMTD in a straw.

The charge shattered the steel disk (not completely of course) and left a fine layer of powdered glass on the dirt walls. (this is why I like using glass containers for my charges, no schrapnel)

The ammonium nitrate was carefully dried in the oven and well powdered with a coffee grinder, the KClO3 was also finely powdered.

jpsmith123 - 20-12-2005 at 15:12

Marvin wrote:

Quote:

Suggesting a 160g booster for detonation does not take it far out of the ANFO catagory it started in anyway, and ANFO can be made on site for most quarry purposes so maybe it passed and just wasn't worth it.

The 160g pentolite booster and the 5 inch critical diameter have me a little puzzled. I wonder if they tried anything less? It's not clear from the patent that they did. I would think that the addition of a chlorate would result in something more sensitive than a typical ANFO type mix.

Anyway, it's claimed that this stuff has high energy and high density, and therefore high bulk strength, so I guess that is the advantage. (BTW it seems some of his mixtures contain no ammonium nitrate).

markgollum wrote:

Quote:

Regarding the sensitivity of chlorate/ ammonium nitrate mixtures. Last year I did an experiment with a charge that consisted of ammonium nitrate and KClO3. As I remember, I used model airplane fuel containing 35% nitromethane 45% methanol and 20% oil.

Compared to the patented mixture, it seems to me that, on the one hand, the nitromethane may have made your mixture more sensitivite to detonation, and on the other hand, your use of the less soluble KClO3 (vs NaClO3), may have had the opposite effect.

Quote:

I first made a small amount of this mixture ~1g.
.3g was heated strongly with a propane torch until only molten KCl remained (no energetic reaction).
~.1g was placed on an iron anvil and struck with a framers hammer, it only splattered. 10 min later after some of the solvents had evaporated, the experiment was repeated with the same result until only ~.2g remained .
Several hours later, once all the NM and MeOH had evaporated, that ~.2g was struck violently with the hammer with no explosion.

Interesting. Thanks for the info.

Quote:

The next day I transported enough of the three ingredients to the blast site seperatly for a total charge wheight of 60g.
The ingredients were added to a small glass jar and thoroughly mixed. The jar was placed in a deep hole on top of an old circular piece of steel from a disking machine and initated with 1.5g HMTD in a straw. The charge shattered the steel disk (not completely of course) and left a fine layer of powdered glass on the dirt walls. (this is why I like using glass containers for my charges, no schrapnel)

I'll speculate that if you'd used NaClO3 or NaClO4, it would have been even more effective.

hodges - 20-12-2005 at 15:59

I know ammonium chlorate is very unstable but I'm not sure its that powerful of an explosive. I've made small (fraction of a gram) amounts before. Perhaps the small amount or the fact that I tested it as soon as it dried (no aging) prevented anything more violent, but it seemed to burn about like poor black powder. It did give off a white smoke (ammonium chloride) as well as a strong smell of chlorine (and possibly oxides of chlorine; I'm not real good at telling these apart by smell).

CRC handbooks says "explodes 102C", but they also say that about silver oxalate, which deflagrates but is generally not self-sustaining (at least not in small quantities). I think anything that will undergo self-decomposition is considered to be "explosive". I've even seen ammonium dichromate termed "explosive".

I've read that ammonium chlorate tends to decompose spontaneously a few days to a few weeks after being formed. Supposedly it emits increasing amounts of ClO2 and heats itself until spontaneous combustion occurs. Immediately after I made it there was no odor of any type of chlorine compounds being given off. Sometime I will have to try leaving a small amount of it sitting around in a safe place to see if it eventually ignites by itself.

I think the danger with ammounium chlorate is this spontaneous ignition. If pyrotechnics are contaminated with ammonium chlorate, they may ignite by themself; that does not necessarily mean they will explode though. Just my thoughts though; I may well be wrong so don't try this at home unless you know what you are doing.

chloric1 - 20-12-2005 at 20:00

I was pondering doing the synthesis of barium chlorate via the ammonium chlorate method mentioned in Brauer's text. Was wondering if anyone here messed around with the aqueous solution from 60 to 85 degrees C? I know this seems risky but this gives a clean cut method and can be done to make strontium chlorate as well.

Boomer - 23-12-2005 at 10:20

Just a side note: For Boomershoot (www.boomershoot.org nothing to do with me) Joe Huffman uses a similar mix but dry (!). I mailed him and he said he knows the risk but tries not to store it for long. There already was a fire at the shooting site after they left some targets outside!

kABOOM! - 24-12-2005 at 21:17

reactive targets are of great interest to me. I'd like to stay the heck away from organic peroxides as they are very unstable... however, what boomershoot uses could be used easily at any firing range.

so, I would like to find a good explosive that could be "shocked" by a bullet and exploded. Yep, tried APAN...MEKP... and they all work, but i'm concerned with their instability.

jpsmith123 - 25-12-2005 at 17:41

After reading the anecdotal account of the fire, I'd say that's a good real-life example of the danger of mixing a chlorate and an ammonium compound.

It seems they are more concerned about cost than safety.

In any case, I wonder if KClO3 and charcoal would work, or maybe a gelled NaClO3/methanol mixture?

hodges - 25-12-2005 at 18:29

I presently have around 0.8g of NH4ClO3 sitting in a small plastic cup. It dried from solution two days ago, and I am leaving it since I will be home for the next few days to watch it. When it first dried it had no odor. I burned a small piece of it; again it burned about as rapidly as black powder. Since then it has turned from white to light yellow, and it is now giving off a weak chlorine smell. I burned another small piece and didn't notice any difference compared to the first time. I have checked the temperature with an infrared thermometer and so far it has not been any warmer than the rest of the cup (resolution 1 degree F).

Swany - 25-12-2005 at 21:33

Interesting on the timetables of the decomposition of NH4ClO3. Do you have any idea how acidic it is, or the solution was? Any variables that may have sped up decomposition would be good to note now. You should do some sensitivity tests...

How did you go about making it? Displacement from KClO3 or similar?

Also with many AN mixtures, they tend to use a massive booster to aid in the decomposition, such that it decomposes into N2 and O2, plus H2O, rather than NO. Much more energy is released, about 4x as much in the former detonation sequence. But, it only happens at very high pressures and temps, I understand. You can detonate ANFO with .5g cap, but it would be a very very sad detonation.

hodges - 26-12-2005 at 14:24

Quote:

Originally posted by Swany
Interesting on the timetables of the decomposition of NH4ClO3. Do you have any idea how acidic it is, or the solution was? Any variables that may have sped up decomposition would be good to note now. You should do some sensitivity tests...

How did you go about making it? Displacement from KClO3 or similar?

I used KClO3 and NH4ClO4, both pyrotechnic quality, so I would expect the solution to be close to neutral.

It has turned more yellow today and is giving off more fumes (but still not too much - I have to get within a few feet of the container to smell it).

Someplace I read details of an experiment (I think from a very old chemistry book) where NH4ClO3 was observed in a water solution over time (the solution was saturated and then more NH4ClO3 was added). I recall a description of a faster and faster decomposition (even under water), as well as that the final product was (somewhat surprisingly) NH4NO3. Does anyone know where I read this?

Update

hodges - 31-12-2005 at 19:51

Well, the NH4ClO3 never ignited, and it now appears to be mostly converted to something more stable. The substance was a translucent white to start with. After a few days, it turned a urine yellow. Now it is back to white and most of the chlorine compound smell has subsided.

I monitored the temperature with an infrared thermometer and never saw it rise at all above the surrounding temperature (resolution 1 degree F). I burned a small amount of this at various points during the decomposition. It seemed to have about the burning speed of black powder for a while but then became less reactive once the yellow color started to go away.

I will leave this sit until the chlorine smell is completely gone, then run some tests to see what the resulting compound is. Unfortunately I won't be able to determine the weight change since I burned part of it along the way.

I suspect there is a critical mass of this compound required for self-ignition. But I'm not willing to make an unpredictable substance in any larger amounts than I did.

chloric1 - 1-1-2006 at 11:22

hodges-I think you are on the ball about the critical mass thing since the chlorate generates its own heat. So if you wanted to play with larger portions, you would keep it spread out to maximize surface area.

jpsmith123 - 9-1-2006 at 03:10

From what I've found on google recently, the latest Boomershoot mixture is supposedly:

4 cups ammonium nitrate
1 cup potassium chlorate
1/4 cup ethylene glycol

Supposedly, an impact from a 22 LR will reliably detonate it.

In any case, I happened across a few other patents that mix chlorates with ammonium nitrate. One patent claims that the addition of small quantities of inorganic water soluble phosphates stabilize such mixtures.