megalomania
June 8th, 2003, 01:14 PM
c0deblue
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posted 05-03-2001 03:51 AM
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Gerald Hurst's Patent # 4,093,478 discloses a method of "activating" Ammonium Nitrate by mixing the prills with a specified percentage (by weight) of water and heat drying to the original (or lower) moisture content. This "activation" process reduces prill density thereby allowing more fuel to be absorbed, and increases the sensitivity so that only a #6 detonator (no booster charge) is needed to initiate the explosive. A sensitizer is desirable but not required.
The patent text is also a veritable treatise on the subject of AN explosives - well worth saving.
Go to the patent number search page http://164.195.100.11/netahtml/srchnum.htm and enter 4093478
[This message has been edited by c0deblue (edited May 03, 2001).]
wantsomfet
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Posts: 236
From: EU
Registered: JAN 2001
posted 05-03-2001 06:11 AM
--------------------------------------------------------------------------------
Me have this & other AN related patents as PDF files at my website - check it out. No need to download the TIFF images...
------------------
for best catfood visit:
kangaroooo.cjb.net
TylerDurden
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Posts: 94
From:
Registered: APR 2001
posted 05-05-2001 12:25 PM
--------------------------------------------------------------------------------
This method of "activating" ammonium nitrate is not new. It's basicly just recrystallisation (of a part) of the (powdered or prilled) ammonium nitrate. And the crystals formed are more sensitive than the prills or AN powder, because of lower density (in fact the density of the crystals is the best you can get, it can't be decreased further: powdered AN is better tan prills and crystals are better than powdered AN). Even in PMJB this method is described: they crystalize AN with methanol which yields AN crystals that when mixed with fuel oil results in a cap sensitive mixture. And it does not matter if you use methanol or water with the prilled or powdered AN. You get the same crystals.
By the way, this does not mean that the patent is useless. It's always good to have some scientific information on how things work.
"with enough soap you could blow up just about anything"
[This message has been edited by TylerDurden (edited May 05, 2001).]
wantsomfet
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Posts: 236
From: EU
Registered: JAN 2001
posted 05-05-2001 07:45 PM
--------------------------------------------------------------------------------
Who said the info is new? The patent is from 1978.
And the density can be decreased further.A large steel vessel of ca. 1m height is filled with a few cm of supersaturated ammonium nitrate solution. Under reduced pressure the soulution is rapidly heated up (a matter of seconds), the water evaporates and leaves a foamed ammonium nitrate of extremely low density. (i think it was about 0,3g/ccm).
------------------
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c0deblue
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Posts: 229
From:
Registered: JAN 2001
posted 05-05-2001 08:19 PM
--------------------------------------------------------------------------------
wantsomfet - Sounds interesting. Any further details on that process?
TylerDurden
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Posts: 94
From:
Registered: APR 2001
posted 05-06-2001 08:02 AM
--------------------------------------------------------------------------------
The process Wantsomfet describes is similar to the way low density ammonium nitrate (LDAN) prills are produced by explosives manufacturers like ICI: a supersaturated AN solution is sprayed down a tower. On the way down the water evaporates which results in LDAN prills (not to confuse with the fertilizer prills (ferilizer grade ammonium nitrate (FGAN) prills), which are of a higher density, sometimes with somekind of coating and not made of pure AN). It's the quick evaporation of the water that results in the low density and very porous prills: it's a bit like foaming. The same happens with the method Wantsomfet describes.
But I thought that even those LDAN prills needed a booster when used in ANFO explosives. And using AN crystals instead results in a cap sensitive ANFO explosive. But maybe that's not just because of the lower density but also the more intimate contact between fuel and AN. Anyway, the use of crystals results in the most sensitive mixtures, as compaired to AN prills or powder: it will produce cap sensitive ANFO.
[This message has been edited by TylerDurden (edited May 07, 2001).]
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 05-11-2001 09:49 AM
--------------------------------------------------------------------------------
I found the patent. It's No. 3,279,965 - "Ammonium Nitrate Explosive Compositions"
".....The porous foam-like ammonium nitrate is prepared by evaporating a thin layer of a concentrate solution of ammonium nitrate in a crystallizer at reduced pressure. The ammonium nitrate foams up and solidifies rapidly under these conditions into an especially porous, expanded stucture having the appearance of foam and a very low density. The crystalline form of the ammonium nitrate prepared in this manner usually corresponds to the normally observed crystalline form of ammonium nitrate. At ambient temperatures, that is about 16 °C to 32 °C, the ammonium nitrate is in the orthorhombic form common at this temperature. However, the lattice structure of the crystals is changed by this procedure and the relative positions of the crytals are modified so that there are a great number of cavities left between the crystals. The ammonium nitrate thus foamed and expanded has a high porosity and a considerable specific surface due to its unique structure, which also results in an ammonium nitrate which has a low density and a high absobtion.
In preparing this expanded and foamed ammonium nitrate , a solution of approximately 92% - 95% ammonium nitrate in about 5% - 8% of water at a temperature of about 140 °C is placed in a crystallizer. When, for example, a crystallizer is used which has a diameter of 1.40 meters, a height of 1 meter, and which is adapted to manufacture 100kg of foamed ammonium nitrate, about 68 - 70 cubic decimeters of solution is introduced into the apparatus, which produces a layer of solution of about 4 - 5cm depth. The crystallizer is then evacuated to a pressure of about 60mm of Hg and the water is evaporated quickly, which causes the ammonium nitrate to foam up. The ammonium nitrate foam thus produced is obtained as a cake which practically fills the crystallizer. The cake is then crushed and, if desired, the crushed particles are screened.
The porous nitrate may be prepared in accordance with any other method and it may be used in the form of porous granules. The particle size of the foamed ammonium nitrate is chosen for convenience, inasmuch as the size of the particles used is relatively unimportant and the outer shape of expanded ammonium nitrate is of minor importance. The important feature is the uniqie expanded structure of the nitrate. Since the fuel penetrates the pores of the expanded, porous nitrate, there is no critical size for the particles. For ease in handling, slightly crushed particles of the foamed ammonium nitrate are generally used. However, the particles are crushed only to the extent necessary to obtain a convenient particle size, and the particles retain the stable, foamed structure.
Ammonium nitrate prepared in this way has an apparent bulk density, in gram per cc varying from 0.1 to 0.85....."
http://odin.prohosting.com/~ratfuck/P_3,279,965.zip
------------------
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kangaroooo.cjb.net
TylerDurden
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Posts: 94
From:
Registered: APR 2001
posted 05-11-2001 12:36 PM
--------------------------------------------------------------------------------
I read the patent. With this foam like AN they can make ANFO that is sensitive to a commercial No. 8 primer or detonator (what's the difference?) even when totally unconfined (in free air).
And they say a commercial no. 8 primer corresponds to 2 gram of mercuryfulminate.
The very low density mixtures can also be used in small diameter tubes.
So I was wrong in saying that AN crystals produced by recrystallisation with water/alcohol produces the most sensitive AN mixtures. They are capsensitive (even to a no.6 I think when confined) but the AN foam produces even more sensitive mixtures. You learn every day. Thanks.
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 05-11-2001 08:38 PM
--------------------------------------------------------------------------------
How should crytals absorb reasonable quantities of liquid sensitizers... They're dense... Think of it, i think you have pretty much knowledge, what i read so far from you...
With really sensitive explosives like acetone peroxide crystals are easier to initate, by what means ever...
------------------
for best catfood visit:
kangaroooo.cjb.net
c0deblue
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Posts: 229
From:
Registered: JAN 2001
posted 05-11-2001 09:59 PM
--------------------------------------------------------------------------------
Good research wantsomfet. Sounds like an easy way to make cap-sensitive AN**. You could probably even use an old pressure cooker for the "crystallizer".
The only question that comes to mind concerns the temperature and pressure specified. The patent calls for the supersaturated AN solution to be 140C initially and then subjected to a vacuum of 60 mm Hg. 140C is *considerably* above the boiling point of water, and the slight vacuum reduces the boiling point still further. How does one even deal with water superheated to >40C above its boiling point without a substantial pressure vessel? Is the boiling point of the saturated solution *that* much higher?
To answer your question wantsomfet, I believe it's not the crystals themselves that are porous - it's the lattice structure formed by the crystals and the interstices of these formations that provide the microporosity essential to lower density and greater absorptive qualities.
[This message has been edited by c0deblue (edited May 12, 2001).]
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 05-12-2001 03:03 PM
--------------------------------------------------------------------------------
Adding salt to water raises it's boiling point but I don't know how much. I'd guess that when you evacuate the crystaliser, the water boils off rapidly giving the AN foam.
Would this foam work well for ammonia dynamite?
TylerDurden
Frequent Poster
Posts: 94
From:
Registered: APR 2001
posted 05-13-2001 06:15 AM
--------------------------------------------------------------------------------
I think Codeblue is right in saying that the crystals are not porous. It's better to say that a porous mass of (small to very small) AN crystals is produced. And it's this mass that absorbs the fuel not the crystals themselves (I know).
And this way the surface of the AN is increased (and the density lowered).
And the reason why such a mass is produced is because the water is everywhere in the AN and tries to escape when heated. And if you speed up the evaporation the AN has no chance to grow into large crystals.
By the way, even if you just dry wet AN by heating in a oven, you get AN that will be capsensitive. But the suggestion of using a pressure cooker to produce this foam is a very good one which makes it (almost) just as easy to produce the AN foam instead.
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 05-03-2001 03:51 AM
--------------------------------------------------------------------------------
Gerald Hurst's Patent # 4,093,478 discloses a method of "activating" Ammonium Nitrate by mixing the prills with a specified percentage (by weight) of water and heat drying to the original (or lower) moisture content. This "activation" process reduces prill density thereby allowing more fuel to be absorbed, and increases the sensitivity so that only a #6 detonator (no booster charge) is needed to initiate the explosive. A sensitizer is desirable but not required.
The patent text is also a veritable treatise on the subject of AN explosives - well worth saving.
Go to the patent number search page http://164.195.100.11/netahtml/srchnum.htm and enter 4093478
[This message has been edited by c0deblue (edited May 03, 2001).]
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 05-03-2001 06:11 AM
--------------------------------------------------------------------------------
Me have this & other AN related patents as PDF files at my website - check it out. No need to download the TIFF images...
------------------
for best catfood visit:
kangaroooo.cjb.net
TylerDurden
Frequent Poster
Posts: 94
From:
Registered: APR 2001
posted 05-05-2001 12:25 PM
--------------------------------------------------------------------------------
This method of "activating" ammonium nitrate is not new. It's basicly just recrystallisation (of a part) of the (powdered or prilled) ammonium nitrate. And the crystals formed are more sensitive than the prills or AN powder, because of lower density (in fact the density of the crystals is the best you can get, it can't be decreased further: powdered AN is better tan prills and crystals are better than powdered AN). Even in PMJB this method is described: they crystalize AN with methanol which yields AN crystals that when mixed with fuel oil results in a cap sensitive mixture. And it does not matter if you use methanol or water with the prilled or powdered AN. You get the same crystals.
By the way, this does not mean that the patent is useless. It's always good to have some scientific information on how things work.
"with enough soap you could blow up just about anything"
[This message has been edited by TylerDurden (edited May 05, 2001).]
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 05-05-2001 07:45 PM
--------------------------------------------------------------------------------
Who said the info is new? The patent is from 1978.
And the density can be decreased further.A large steel vessel of ca. 1m height is filled with a few cm of supersaturated ammonium nitrate solution. Under reduced pressure the soulution is rapidly heated up (a matter of seconds), the water evaporates and leaves a foamed ammonium nitrate of extremely low density. (i think it was about 0,3g/ccm).
------------------
for best catfood visit:
kangaroooo.cjb.net
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 05-05-2001 08:19 PM
--------------------------------------------------------------------------------
wantsomfet - Sounds interesting. Any further details on that process?
TylerDurden
Frequent Poster
Posts: 94
From:
Registered: APR 2001
posted 05-06-2001 08:02 AM
--------------------------------------------------------------------------------
The process Wantsomfet describes is similar to the way low density ammonium nitrate (LDAN) prills are produced by explosives manufacturers like ICI: a supersaturated AN solution is sprayed down a tower. On the way down the water evaporates which results in LDAN prills (not to confuse with the fertilizer prills (ferilizer grade ammonium nitrate (FGAN) prills), which are of a higher density, sometimes with somekind of coating and not made of pure AN). It's the quick evaporation of the water that results in the low density and very porous prills: it's a bit like foaming. The same happens with the method Wantsomfet describes.
But I thought that even those LDAN prills needed a booster when used in ANFO explosives. And using AN crystals instead results in a cap sensitive ANFO explosive. But maybe that's not just because of the lower density but also the more intimate contact between fuel and AN. Anyway, the use of crystals results in the most sensitive mixtures, as compaired to AN prills or powder: it will produce cap sensitive ANFO.
[This message has been edited by TylerDurden (edited May 07, 2001).]
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 05-11-2001 09:49 AM
--------------------------------------------------------------------------------
I found the patent. It's No. 3,279,965 - "Ammonium Nitrate Explosive Compositions"
".....The porous foam-like ammonium nitrate is prepared by evaporating a thin layer of a concentrate solution of ammonium nitrate in a crystallizer at reduced pressure. The ammonium nitrate foams up and solidifies rapidly under these conditions into an especially porous, expanded stucture having the appearance of foam and a very low density. The crystalline form of the ammonium nitrate prepared in this manner usually corresponds to the normally observed crystalline form of ammonium nitrate. At ambient temperatures, that is about 16 °C to 32 °C, the ammonium nitrate is in the orthorhombic form common at this temperature. However, the lattice structure of the crystals is changed by this procedure and the relative positions of the crytals are modified so that there are a great number of cavities left between the crystals. The ammonium nitrate thus foamed and expanded has a high porosity and a considerable specific surface due to its unique structure, which also results in an ammonium nitrate which has a low density and a high absobtion.
In preparing this expanded and foamed ammonium nitrate , a solution of approximately 92% - 95% ammonium nitrate in about 5% - 8% of water at a temperature of about 140 °C is placed in a crystallizer. When, for example, a crystallizer is used which has a diameter of 1.40 meters, a height of 1 meter, and which is adapted to manufacture 100kg of foamed ammonium nitrate, about 68 - 70 cubic decimeters of solution is introduced into the apparatus, which produces a layer of solution of about 4 - 5cm depth. The crystallizer is then evacuated to a pressure of about 60mm of Hg and the water is evaporated quickly, which causes the ammonium nitrate to foam up. The ammonium nitrate foam thus produced is obtained as a cake which practically fills the crystallizer. The cake is then crushed and, if desired, the crushed particles are screened.
The porous nitrate may be prepared in accordance with any other method and it may be used in the form of porous granules. The particle size of the foamed ammonium nitrate is chosen for convenience, inasmuch as the size of the particles used is relatively unimportant and the outer shape of expanded ammonium nitrate is of minor importance. The important feature is the uniqie expanded structure of the nitrate. Since the fuel penetrates the pores of the expanded, porous nitrate, there is no critical size for the particles. For ease in handling, slightly crushed particles of the foamed ammonium nitrate are generally used. However, the particles are crushed only to the extent necessary to obtain a convenient particle size, and the particles retain the stable, foamed structure.
Ammonium nitrate prepared in this way has an apparent bulk density, in gram per cc varying from 0.1 to 0.85....."
http://odin.prohosting.com/~ratfuck/P_3,279,965.zip
------------------
for best catfood visit:
kangaroooo.cjb.net
TylerDurden
Frequent Poster
Posts: 94
From:
Registered: APR 2001
posted 05-11-2001 12:36 PM
--------------------------------------------------------------------------------
I read the patent. With this foam like AN they can make ANFO that is sensitive to a commercial No. 8 primer or detonator (what's the difference?) even when totally unconfined (in free air).
And they say a commercial no. 8 primer corresponds to 2 gram of mercuryfulminate.
The very low density mixtures can also be used in small diameter tubes.
So I was wrong in saying that AN crystals produced by recrystallisation with water/alcohol produces the most sensitive AN mixtures. They are capsensitive (even to a no.6 I think when confined) but the AN foam produces even more sensitive mixtures. You learn every day. Thanks.
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 05-11-2001 08:38 PM
--------------------------------------------------------------------------------
How should crytals absorb reasonable quantities of liquid sensitizers... They're dense... Think of it, i think you have pretty much knowledge, what i read so far from you...
With really sensitive explosives like acetone peroxide crystals are easier to initate, by what means ever...
------------------
for best catfood visit:
kangaroooo.cjb.net
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 05-11-2001 09:59 PM
--------------------------------------------------------------------------------
Good research wantsomfet. Sounds like an easy way to make cap-sensitive AN**. You could probably even use an old pressure cooker for the "crystallizer".
The only question that comes to mind concerns the temperature and pressure specified. The patent calls for the supersaturated AN solution to be 140C initially and then subjected to a vacuum of 60 mm Hg. 140C is *considerably* above the boiling point of water, and the slight vacuum reduces the boiling point still further. How does one even deal with water superheated to >40C above its boiling point without a substantial pressure vessel? Is the boiling point of the saturated solution *that* much higher?
To answer your question wantsomfet, I believe it's not the crystals themselves that are porous - it's the lattice structure formed by the crystals and the interstices of these formations that provide the microporosity essential to lower density and greater absorptive qualities.
[This message has been edited by c0deblue (edited May 12, 2001).]
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 05-12-2001 03:03 PM
--------------------------------------------------------------------------------
Adding salt to water raises it's boiling point but I don't know how much. I'd guess that when you evacuate the crystaliser, the water boils off rapidly giving the AN foam.
Would this foam work well for ammonia dynamite?
TylerDurden
Frequent Poster
Posts: 94
From:
Registered: APR 2001
posted 05-13-2001 06:15 AM
--------------------------------------------------------------------------------
I think Codeblue is right in saying that the crystals are not porous. It's better to say that a porous mass of (small to very small) AN crystals is produced. And it's this mass that absorbs the fuel not the crystals themselves (I know).
And this way the surface of the AN is increased (and the density lowered).
And the reason why such a mass is produced is because the water is everywhere in the AN and tries to escape when heated. And if you speed up the evaporation the AN has no chance to grow into large crystals.
By the way, even if you just dry wet AN by heating in a oven, you get AN that will be capsensitive. But the suggestion of using a pressure cooker to produce this foam is a very good one which makes it (almost) just as easy to produce the AN foam instead.