Sciencemadness Discussion Board - nano ammonium nitrate/aluminium mix.. can it exceeding CL-20 ?!

nano ammonium nitrate/aluminium mix.. can it exceeding CL-20 ?!

bodo man - 25-8-2016 at 01:13

by calculation ammonium nitrate-36% aluminium can generate almost 2.5 times energy generated by TNT !!

this is the equation :

10 Al + 6 NH4NO3 = 5 Al2O3 + 6 NH3 + 3 N2 + 3 H2O + 11.16 MJ/ Kg

TNT generating between 4.2 - 4.6 MJ/Kg only !

so, if we using very fine nano aluminium and ammonium nitrate powders (<20 nm size) , and putting the mixture in a very tight moisture proof container can it be a very powerful cheap explosive exceeding CL-20 and equal to a very expensive octanitrocubane ?!

If it can’t work then what about using another nano-sized oxidizer ?!

sorry for my bad english

Metacelsus - 25-8-2016 at 05:42

I would think the stoichiometry would be:
2 Al + 3 NH4NO3 = Al2O3 + 3 N2 + 6 H2O

Also, there might be storage stability issues with this mixture. Energy density, while important, isn't the only thing that determines the quality of an explosive.

PHILOU Zrealone - 25-8-2016 at 05:55

You would get even more energy/kg if you balanced wel your equation...NH3 is a fuel and as such contains a lot of energy.
2 Al + 3 NH4NO3 --> Al2O3 + 3 N2 + 6 H2O

On a theorical level if you could do at the atomic level a perfect mix of Al atoms and NH4NO3 molecules...then you would probably get a very powerful energetic material.
Sadly theorical is far from reality where such mix would be spontaneously inflamable and incredibely sensitive. Such Al dust would even be inflamable from open air...

Also a kilo of pure C, H2 or even CH4 (or benzine) would produce even more energy...but are not really interesting/practical explosives.

[Edited on 25-8-2016 by PHILOU Zrealone]

MineMan - 25-8-2016 at 07:29

Emulsions fulfill this criteria. They are mixed at the molecular level. It is AN dissolved in water with a fuel added (diesel) and then emulsified. This produces intimate contact at the molecular level. Sometimes Al is added also, but only up to 10 percent, much more can cause unwanted hydrogen gas ( if blasting, you don't want hydrogen leaking out of the rocks you just blasted.)

These have a VOD of about 6000ms. And their densities don't come close to the 2.0 of CL-20. I fact these mixtures need microballoons for reliable detonation.

PHILOU Zrealone - 25-8-2016 at 07:56

Quote: Originally posted by MineMan

Emulsions fulfill this criteria. They are mixed at the molecular level. It is AN dissolved in water with a fuel added (diesel) and then emulsified. This produces intimate contact at the molecular level. Sometimes Al is added also, but only up to 10 percent, much more can cause unwanted hydrogen gas ( if blasting, you don't want hydrogen leaking out of the rocks you just blasted.)

These have a VOD of about 6000ms. And their densities don't come close to the 2.0 of CL-20. I fact these mixtures need microballoons for reliable detonation.

They also contain a lot of water what tempers the heat of explosions and thus the gas expension --> less work

A gelous stuff (gelifier) is incorporated in a way to keep the Al and the microballoons suspended homogeneously...otherwise they would sediment (concentrate into the lowest part).

VOD is between 3000m/s to 6000m/s but the last contains extra boosters like NM or NG...

[Edited on 25-8-2016 by PHILOU Zrealone]

ecos - 25-8-2016 at 08:01

if you go for very small particle size of Al (nm) it will be very very active. a drop of water will make it release heat. ALICE propellant is a prove to that.
AN is very gyroscopic and this make the mix not stable with Al in nm

if you add Al and AN in ball miller and keep it running till you reach nm, you definitely make a very very sensitive mixture. it will not be stable as well.

watch this video to see how active is nAl : https://www.youtube.com/watch?v=iIq9VvZeWKo

Dany - 25-8-2016 at 10:27

Definitely the performance of the AN/Al mixture (called AMMONAL) is always inferior to the performance of common military explosives such as TNT and TATB. The calculated 11.16 MJ/Kg value is obtained on the basis that all the aluminium burn to form Al₂O₃ which in fact is far from being realized in a detonation. Unfortunately, the aluminium combustion is a slow process, so that the energy released by the oxidation of the aluminium becomes available much too late to influence conditions in the detonation reaction zone. This has a dramatic effect on the detonation performance and a lowering of the detonation velocity/pressure will be obtained. Another problem with heterogeneous explosive mixtures is the long time required for the oxidizer/fuel particle to react. These reactions are controlled by diffusion (or other transport phenomena) and also by the temperature which may control the ammonium nitrate decomposition. You may increase the detonation velocity/pressure by decreasing the particle size of the oxidizer and fuel but the performance will always be inferior to monomolecular high explosives. On the other hand, aluminium containing explosives have very good blast properties due to the combustion of aluminium particles with surrounding atmosphere (i.e. the combustion of aluminium with air is greatly enhanced due to turbulence created at the aluminium/air interface). At a determined distance from the charge, A higher blast/impulse is obtained from a metal containing explosive compared to a monomolecular high explosive.

Dany.

nano aluminium/ nano ammonium perchlorate mix , how much strong ?!

bodo man - 25-8-2016 at 12:24

if there is a way to produce nano amm. perchlorate powder , then mixing it with nano aluminium powder in a stichiometric mixture , how much it will be strong ?!

from my calculation the Al/AP mixture can produce 11.6 MJ/Kg :

10Al + 6 NH4ClO4 → 6 HCl + 3 N2 + 9 H2O + 5 Al2O3

metal powders in the nano-sized range are very active , very strong reducing agents and have high surface area , so very high rate of burning is expected ! very high burning rate means simply strong explosion , am I right ?!

I think if the powders are < 10 nm size the burning rate will exceeding some strong mono explosives !!

the mixture also producing a good amount of gases ( 470 g/Kg mix.) wich adding some good amount of brisance !

can this mixture really being a very strong explosive exceeding HMX , CL-20 and maybe Octanitrocubane ?!

11.6 MJ/Kg equal to 2.5 times as TNT , so if it worked it will be very powerful explosive !!

PHILOU Zrealone - 25-8-2016 at 12:32

Same kind of question as your first...same kind of reply! The answer is the same!

By the way your post has been displaced to Beginning section...no doubt this post will be merged with it.

bodo man - 25-8-2016 at 12:40

Quote: Originally posted by PHILOU Zrealone

Same kind of question as your first...same kind of reply! The answer is the same!

By the way your post has been displaced to Beginning section...no doubt this post will be merged with it.

no... the first post about ammonium nitrate , this one about ammonium perchlorate , there is a difference

also the equation in this post is more reality than the old one

[Edited on 25-8-2016 by bodo man]

Dany - 25-8-2016 at 13:21

When it come to performance, there is nothing special about oxidizers/fuels mixtures for the reasons explained in my previous comment here

http://www.sciencemadness.org/talk/viewthread.php?tid=68488&...

An extensive study on AP/Al mixtures has been made by Price et. al [1]. Experimental detonation velocities for a series of AP/Al (95/5; 90/10 and 80/20 AP/Al) were obtained and the results show that the detonation velocity did not exceeded 5 km/s. The mixtures were based on micron-sized AP and Al.

Reference:

[1] Price D., Clairmont A. R., Erkman J. O. Explosive Behavior of Aluminized Ammonium Perchlorate, Naval Ordnance Laborarory Report NOLTR 72-15, 1972.

Dany.

ecos - 25-8-2016 at 17:19

why you talk just about theoretical things !
if you have nm particle size , everything will be very sensitive !
not safe mixtures to handle or use.

ecos - 25-8-2016 at 17:25

if you continue in making new threads like this. it will end up with a new topic like :
Tritonal will be the best EM if we use nAl

[Edited on 26-8-2016 by ecos]

[Edited on 26-8-2016 by ecos]

bodo man - 25-8-2016 at 17:35

Quote: Originally posted by Dany

When it come to performance, there is nothing special about oxidizers/fuels mixtures for the reasons explained in my previous comment here

http://www.sciencemadness.org/talk/viewthread.php?tid=68488&...

An extensive study on AP/Al mixtures has been made by Price et. al [1]. Experimental detonation velocities for a series of AP/Al (95/5; 90/10 and 80/20 AP/Al) were obtained and the results show that the detonation velocity did not exceeded 5 km/s. The mixtures were based on micron-sized AP and Al.

Reference:

[1] Price D., Clairmont A. R., Erkman J. O. Explosive Behavior of Aluminized Ammonium Perchlorate, Naval Ordnance Laborarory Report NOLTR 72-15, 1972.

Dany.

thank you for this study , I will read it , but I think a 5km/s is good for the micron sized powder .

considering that the deflagration index for micron sized Al powder is less than 80 compared to 35 nm powder wich can reach 350 easily , that is a very big favourable difference .

I think also FAOB containing nano Al powder and it is very powerful and energy dense bomb anyway !

bodo man - 25-8-2016 at 17:39

Quote: Originally posted by ecos

if you continue in making new threads like this. it will end up with a new topic like :
Tritonal will be the best EM if we use nAl

[Edited on 26-8-2016 by ecos]

[Edited on 26-8-2016 by ecos]

nuclear bombs will be best EM if we used nano Al

Bert - 25-8-2016 at 20:39

Somehow, this all seems very familiar. Could you please just go find a nice boyfriend/girlfriend/appropriate antipsychotic medication regime/adequate drug abuse treatment facility/some other unspecified, but more appropriate oulet for teh crazies- and leave this forum the fuck alone? You are a BORE.

nitro-genes - 26-8-2016 at 05:06

Interesting read, I was actually somewhat surprised to see no effect at all on detonation velocity comparing alex and regular Al powder in PBX compositions (table 2 and 3). Nano-Al just sounds too funky for that.

[Edited on 26-8-2016 by nitro-genes]

Attachment: DETONATION PROPERTIES OF EXPLOSIVES CONTAINING NANOMETRIC ALUMINUM POWDER.pdf (355kB)
This file has been downloaded 677 times

ecos - 26-8-2016 at 06:57

@nitro-genes, the attached file is considering sizes between 100-200 nm
if you choose particles between 10-5 nm it will be super active and effective!
the shape of the particle also matters as far as i know.

nitro-genes - 26-8-2016 at 07:30

Hi Ecos,

Didn't know particle sizes of 5-10 nm were also available, do you have any reference on the use of this in explosive compositions?

Comparing with emulsions somewhat earlier, what is the average size again for the droplets? Although these fuel droplets may behave more different than solid particles of aluminium when hit by the detonation wave, they are about comparibly small IIRC. Maybe this suggests that something inherent to the aluminium makes that the VoD is actually not affected and (surprisingly) even slightly decreased for nano size aluminium compared to micron sized. Maybe the aluminium oxide formed in the reaction zone is very detrimental somehow and the most influential here.

[Edited on 26-8-2016 by nitro-genes]

ecos - 26-8-2016 at 10:18

it seems I made a mistake. I got confused by units.
I was talking about range of 5-10 um not nm

sorry for this mistake !

the smallest particle size I am aware of is 40 nm : http://www.us-nano.com/inc/sdetail/467

[Edited on 26-8-2016 by ecos]

[Edited on 26-8-2016 by ecos]

nitro-genes - 26-8-2016 at 12:30

No problem, it is confusing especially considering alumina and aluminium are different things and with decreasing particle sizes, this distinction may further become less relevant anyway

Would it somehow be possible to reduce the surface tension of molten metals? I had the idea that spray techniques of producing spherical aluminium would not be effective due to the high viscosity and surface tension of molten aluminium. It would be much cheaper to produce nano-al if this were possible, maybe using a (afterwards removable) flux of some kind or alloy composition. Any thoughts on whether this is possible?

nitro-genes - 27-8-2016 at 03:02

Would hardness of the metal powder used matter? Would there be any difference between a very brittle magnalium alloy powder and aluminium alone? Or would the timeframe during detonation be too short to have any effect? If you would design the most brittle alloy using magnesium and aluminium and lower speed of sound too as low as possible, would it behave thermobaric like a powder?

Dany - 27-8-2016 at 12:15

nitro-genes,

The hardness of the metal or whether the metal is considered compressible or incompressible are all of little significance for the detonation performance in condensed high explosives. If the metal is treated as compressible this will result in a slight lowering of the detonation performance because a fraction of the energy available in the detonation wave will be used to compress the metal. However, in highly metallized compositions the density of the metal may have a tremendous effect on the local brisance of the explosive. The plate dent test is known to be a reliable method for the determination of the brisance of an explosive. The dent produced by a detonating explosive on a witness steel/aluminium plate correlate well with available detonation pressure of C-H-N-O explosives. However, when a high density metal such as lead or tungsten is present, a deeper dent is observed on the witness plate despite the fact that the addition of the metals lowers the detonation pressure. As explained by Dr. Charles MADER [1]: If the plate dent depth fails to correlate with the C-J pressure, as for the inert metal (e.g. lead, tungsten, etc..) loaded explosives, the explosive is exhibiting unique isentropic expansion properties.

Reference:

[1] C. L. Mader, Numerical modeling of explosives and propellants, CRC, Boca Raton (Fla.), 2008.

Dany.

[Edited on 27-8-2016 by Dany]

AJKOER - 27-8-2016 at 18:11

In my prior research on N2O, I recall some commentary on the extreme temperature that a N2O infused fuel explosion could produce.

Fortunately, a powerful primer is required for detonation, although an electrostatic discharge apparently is responsible for some N2O/fuel (including solvents) accidental explosions.

See https://www.google.com/url?sa=t&source=web&rct=j&...

A N2O/fuel/NH4NO3/Al mix may have some interesting properties on detonation.

[Edited on 28-8-2016 by AJKOER]

nitro-genes - 31-8-2016 at 05:13

Thanks Dany, is that similar to what is happening in the graph below, very surprising effect that the VoD rapidly goes up with increasing aluminium content? What causes this effect, the relatively high speed of sound for metals? Interesting phenomena, can't directly fold my head around this.

Ref --> http://what-when-how.com/nanoscience-and-nanotechnology/meta...

ecos - 31-8-2016 at 06:43

doesn't HMX has VoD = 9100 m/s ?

PHILOU Zrealone - 14-9-2016 at 04:12

Quote: Originally posted by ecos

doesn't HMX has VoD = 9100 m/s ?

Depends on density...9100 at max density.

@Nitro-genes,
I'm rolling on floor laughing by reading their meaning of HMX...hexamethyl-3-nitroamine...what makes all their text doubtfull.
Also why did they stop at 50% Aluminium? It seems that at 60% one may expect VOD 8000m/s...since there is no sign of slope change...???

Speed of sound in metals is high if:
-dense (but this is not the most important factor)
-rigid (elasticity modulus is linked ... thus low compressivity)
None of those apply to Aluminium.
-And most of all into a continuous media (a block of metal)
This certainly doesn't apply to Aluminium powder which is surrounded by air voids thus limiting the speed of sound to 350m/s.
-solid (speed of sound is faster into solids than into liquids and itself faster than into gases).

Also a powder surrounded by air will interfere with sound propagation into one direction since each interface change will deviate the soundwave.

To get a high speed of sound into a solid material one has to play with dense, crystaline material (ideally monocrystalline),...usually very hard ("uncompressible" thus with rigid...each modification of the crystal latice comes back to its original state very fast).

[Edited on 14-9-2016 by PHILOU Zrealone]

nitro-genes - 20-9-2016 at 13:44

Haha, maybe hexamethyl-3-nitroamine (unlike HMX) has a very unique structure, only surpassed by its amazing detonation properties.

Just noticed the VoD going up with increasing Al content and made a post. It's almost as if one of the axis is reversed, but seen the graph was likely copy pasted from the original reference mentioned this also seems strange, should have read the original article regarding details of the experiments before posting. At the compositions TMD, Its is interesting to think about how the speed of sound and density of the metal powder affects detonation properties, though I haven't really looked into this yet.

PHILOU Zrealone - 6-5-2017 at 15:15

Maybe that the increase of apparent VOD is linked to their method of determination of the VOD....

If they used a plate dent test to correlate with the VOD...it is wel possible that the metallic dust plays a role similar to shaped charge or explosive formed projectile (EFP)...thus meaning that somehow the Gurney energy (metal acceleration effect) is at play...

This means for example that if you have:
A) 3 gr explosive plate dent test
B) 2 gr explosive and 1 gr metal X shaped charge
C) 2 gr explosive and 1 gr metal X powder
Then probably the plate dent test relative power or VOD/brisance will be into the order B> C >> A