Sciencemadness Discussion Board

Grinding Ammonium Nitrate?

maxenzo2 - 13-4-2015 at 05:24

I know its probably a stupid question,is it any safe to grind ammonium nitrate on a coffee grinder? i didnt do it and i wont do it,because im affraid and probably very dangerous,but i had to ask.

szuko03 - 13-4-2015 at 07:33

Ammonium nitrate is hard to detonate and requires a primary blast, of significant strength to set it off, you will not be able to achieve the activation energy by blending it. I would say there is almost 0% risk here, though some crazy unforeseen thing is always possible so its never fully 0 with energetics

Forgot to add that it is just the oxidizer and ANFO mixtures require the "FO" to be explosive.

[Edited on 13-4-2015 by szuko03]

macckone - 14-4-2015 at 06:45

If it gets too hot, generally from a fire, it can detonate. The 1947 Texas City disaster is probably the best example but that was coated with paraffin. A more recent example of straight AN exploding is the West, TX disaster. A ball mill is relatively easy to make and much less likely to cause a problem than a coffee grinder. Coffee grinders can get fairly hot (depending on the model) and may be sufficient to start AN burning.

Loptr - 14-4-2015 at 07:13

Quote: Originally posted by macckone  
If it gets too hot, generally from a fire, it can detonate. The 1947 Texas City disaster is probably the best example but that was coated with paraffin. A more recent example of straight AN exploding is the West, TX disaster. A ball mill is relatively easy to make and much less likely to cause a problem than a coffee grinder. Coffee grinders can get fairly hot (depending on the model) and may be sufficient to start AN burning.


I have heard AN referred to as a "marginal explosive." It doesn't typically explode by itself in small quantities. Yes, heat will do the trick, but you need a lot of AN, quite a bit more than a 50 lb sack.

In fact, I imagine the actual explosion of AN from fire alone is quite complex, and possibly due to oxygen production from thermal decomposition, molten AN, disassociation of the ammonia gas (flammable and a reducing agent) from the nitrate anion, oxidation of the ammonia gas, heat, repeat, etc., etc., just one huge chain of events that leads to a critical event that escalates very quickly resulting in an explosion, but this is just my initial line of thinking.

And mind you, I have never worked with high order explosives, so I know very little about the actual stages leading up to detonations.

[Edited on 14-4-2015 by Loptr]

Can AN vaporize before decomposing? That might also be one vector.

[Edited on 14-4-2015 by Loptr]

macckone - 14-4-2015 at 08:28

I doubt a grinder is going to set off AN but why take chances.
If it gets hot it can burn. If it starts burning, it can explode.
Even small explosions can seriously injure someone.

A ball mill is easy to make and inexpensive.
Use the right equipment when dealing with anything potentially
explosive.

A few examples:
http://www.instructables.com/id/Make-a-Ball-Mill-in-5-Minute...
http://www.instructables.com/id/Making-a-ball-mill/
https://www.youtube.com/watch?v=pHyW7a-ihbc

Loptr - 14-4-2015 at 13:57

Quote: Originally posted by macckone  
I doubt a grinder is going to set off AN but why take chances.
If it gets hot it can burn. If it starts burning, it can explode.
Even small explosions can seriously injure someone.

A ball mill is easy to make and inexpensive.
Use the right equipment when dealing with anything potentially
explosive.

A few examples:
http://www.instructables.com/id/Make-a-Ball-Mill-in-5-Minute...
http://www.instructables.com/id/Making-a-ball-mill/
https://www.youtube.com/watch?v=pHyW7a-ihbc



Problem is that AN burns pretty slowly, so the amount of energy being released at any one point is time is pretty low, hence the need for large amounts.

Bot0nist - 15-4-2015 at 10:59

It's fine, IMO. I and others have done it often. Even if it gets really hot it will likely just start to melt, and or the blender will burn out. Ammonium nitrate, without a reasonable amount of fuel had essentially zero risk of detonating. Obviously, this does not apply to grinding premixed pyrotechnic materials that include ammonium nitrate and fuels. Thus still will not result in a detonation, but could very well ignite and burst the grinder or blender.

I have read warnings about the possibility of liquid ammonium nitrate being more sensitive, especially with certain ions, like copper present. This was during a discussion about the production of laughing gas from molten ammonium nitrate, and was only touched on. As far as I know, even fools who tried this over an open flame were not frequently blown up. The inclusion and inhalation of harmful nitrogen oxides is a real concern in that method for nitrous oxide.

Edit: And I agree with loptr's thinking about the dynamics of unaduterated or sensitized ammonium nitrate detonating. It is likely a very complex process, and seems to require very large amounts, confinement, and hellish conditions, like what would be found in an large industrial fire.

[Edited on 15-4-2015 by Bot0nist]

[Edited on 16-4-2015 by Bot0nist]

Loptr - 15-4-2015 at 12:00

I have set a pile of AN + spherical aluminum on fire before. It had a nice slow burn with lots of heat, and in fact, at the time I thought it might make for a good camping fuel source for cooking contained food. It was also very hard to ignite, which could probably be alleviated with more intimate mixing.

(honestly, that is the first thing that popped into my head when I observed the flame; probably unhealthy, though)

[Edited on 15-4-2015 by Loptr]

[Edited on 15-4-2015 by Loptr]

zed - 17-4-2015 at 11:42

I wouldn't do that. Or, at least, I would be very cautious. Got a local fella, sells a bomb type thing. Detonates when impacted by a high velocity round. Sufficient force to blow a car to smithereens. Just a nice intimate mixture of Aluminum powder and AN.

Somehow, at least here in Oregon, this is not illegal. Just red blooded Americans, blowing things up, strictly fer the fun of it.

By the way, if you play this game.... Watch out for flying car smithereens. Moving at six hundred feet per second, they can badly shred your cummerbund.

[Edited on 17-4-2015 by zed]

[Edited on 17-4-2015 by zed]

Loptr - 17-4-2015 at 11:56

Quote: Originally posted by zed  
I wouldn't do that. Or, at least, I would be very cautious. Got a local fella, sells a bomb type thing. Detonates when impacted by a high velocity round. Sufficient force to blow a car to smithereens. Just a nice intimate mixture of Aluminum powder and AN.

Somehow, at least here in Oregon, this is not illegal. Just red blooded Americans, blowing things up, strictly fer the fun of it.

By the way, if you play this game.... Watch out for flying car smithereens. Moving at six hundred feet per second, they can badly shred your cummerbund.

[Edited on 17-4-2015 by zed]

[Edited on 17-4-2015 by zed]


That sounds like a tannerite analog. It does require a high velocity round in order to set it off, not something you can get to go off from grinding it.

diggafromdover - 17-4-2015 at 12:04

Well said Zed

macckone - 18-4-2015 at 10:30

Quote: Originally posted by Loptr  
Quote: Originally posted by zed  
I wouldn't do that. Or, at least, I would be very cautious. Got a local fella, sells a bomb type thing. Detonates when impacted by a high velocity round. Sufficient force to blow a car to smithereens. Just a nice intimate mixture of Aluminum powder and AN.

Somehow, at least here in Oregon, this is not illegal. Just red blooded Americans, blowing things up, strictly fer the fun of it.

By the way, if you play this game.... Watch out for flying car smithereens. Moving at six hundred feet per second, they can badly shred your cummerbund.

[Edited on 17-4-2015 by zed]

[Edited on 17-4-2015 by zed]


That sounds like a tannerite analog. It does require a high velocity round in order to set it off, not something you can get to go off from grinding it.


Tannerite adds ammonium perchlorate, titanium powder and zinc hydroxide.

http://worldwide.espacenet.com/publicationDetails/biblio?CC=...

Again why take chances with a coffee grinder when you can make a good ball mill for $20.

aga - 18-4-2015 at 11:21

Just grind it while damp maybe ?

Dry the powder later ...

Loptr - 18-4-2015 at 11:48

Quote: Originally posted by aga  
Just grind it while damp maybe ?

Dry the powder later ...


AN is hard enough to keep dry. I have seen ground AN turn to a puddle of liquid before just being in air.

Besides, grinding AN is not the issue. It's tons of AN being located in the same place, combined with a ongoing disaster, which results in the AN making it even more disastrous.

[Edited on 18-4-2015 by Loptr]