the use of AN [Published]
AndersHoveland
Acolyte
This post is a compilation of various information about the use of ammonium nitrate (AN) in compositions.
Addition of Sensitizers
For compositions, the best fuel additive to add into AN is hexamine di-nitrate. Hexamine di-nitrate (HDN) is fuel-rich, and is an ionic salt like AN, so if the two powders are finely crushed they can be much better mixed together than if other fuels had been used. This mixture would be on a very small scale, not quite a molecular scale like double salts, but almost. This means that the detonation velocity of an AN-HDN composition can be substancially higher than an AN-fuel mixture.
Hexamine di-nitrate, also referred to as hexamethylenetetramine dinitrate, (HDN) is an explosive by itself (containing both "fuel" positively charged hexamine ions, and "oxidizer" nitrate ions).
The molecular formula of HDN is C6H14N6O6 , which should indicate that it is overall fuel-rich. In other words, the decomposition products contain carbon and carbon monoxide that could be further burnt off by some other compound that is a net oxidizer, such as AN.
The molecular structure of HDN could also be expressed as (CH2)6N4*(2)HNO3. It should be noted that HDN is a very insensitive explosive, and although it is somewhat easier to detonate than AN, it still requires a fairly powerful blasting cap to be detonated. Mixing finely powdered HDN into finely powdered AN, will make the composition easier to detonate than AN alone, thus HDN can be considered a sensitizer.
During the preparation of HDN, if too much acid is used and it is too concentrated, it is possible that the hexamine may disproportionate and hydolyze into formic acid and methylamine nitrate.
Such products can nevertheless still be used to sensitize AN.
Chlorates should not be mixed with ammonium compounds. AN absorbs moisture from the air, and this water could dissolve both the AN and chlorate. Ammonium chlorate is much less soluble than sodium chlorate (normally however ammonium compounds are much more soluble) and can easily precipitate out as a solid. Ammonium chlorate is unstable, and can start to rapidly decompose in sunlight, the decomposition eventually initiating an explosion.
Perchlorates can be mixed with AN without risk. Ammonium perchlorate is more sensitive to detonation than AN, so presumably adding a perchlorate salt to AN could make it easier to initiate.
Using Acetone Peroxide with Ammonium Nitrate: Not a good idea!
Not only is acetone peroxide very unsafe, but it is also a poor initiator of other main charges since it is mostly an "entropic explosive" (most of the effective energy released is in the form of resultant gases that take up a larger volume, not heat)
Organic peroxides and ammonium nitrate compositions are much simpler to prepare, and use more readily available precursors, than any other improvised explosive.
Yet in terms of sensitivity, organic peroxides and AN compositions are at completely different extremes of sensitivity. Organic peroxides are one of the most dangerously sensitive types of explosives. The only explosives more sensitive are the ones that usually spontaneously explode for no reason soon after preparation. Organic peroxides have been described as several times more sensitive to friction than even nitroglycerin.
Ammonium nitrate compositions are the most insensitive (difficult to detonate) type of explosives. It requires a fairly powerful explosion for AN to itself detonate. AN compositions typically do not explode when shot with a rifle, or placed into a fire. For experimenters with improvised ingredients, it can be very difficult to get an AN composition to detonate. Components which act as semsitizers are often part of the composition, making it easier to detonate the AN. However, even with the addition of most types of sensitizers, the AN composition still requires a sufficient explosion to detonate.
Both organic peroxides and AN compositions give off much less heat when they explode than most other explosives. Most of the power of the explosion is from the formation of gas, which has a cooling effect as it expands. From one perspective, it could be stated that much of the energy from these explosives comes from the ambient (room temperature) heat in the solid explosives before they explode. These types of explosives are referred to as "entropic explosives".
Additives to Add Power
Do not try this, but mixing both some hydrazine and NM into AN makes the composition extremely powerful, and much easier to detonate (even adding 5% by weight hydrazine to AN makes it twice as sensitive). The nitromethane actually mixes with the hydrazine (it forms a sort of liquid "ionic compound", hydrazinium nitromethanate)
Alternatively, dimethyl hydazine is substancially better than plain hydrazine mixed into AN, this was one of the lesser known Astrolite variants. Of course, hydrazine compounds give off toxic vapor. Preparing dimethyl hydrazine from common substances is actually fairly easy, but you will have to find the procedure somewhere else.
Physical Safety
Actually never recommend putting explosives inside pipes for safety reasons. Hard sharp plastic fragments could be propelled out potentially hurting someone, usually the experimenter.
Power of Plain ANFO
Explosives are in many ways completely different from pyrotechnics. All too often those familiar with pyrotechnics think explosives are merely mixes of fuel and oxidizer. This is generally not true. Explosives have a much faster reaction rate than pyrotechnics, the combustion reaction in a mechanical mixture of two powders is limited by surface area, and the reaction will be much slower than two liquids mixed together, for example. Finely pulverizing the solid powders into small particles helps increase reaction rate, but can still never approach the reaction rate of compounds that contain both fuel and usable oxygen together in their molecular structures.
ANFO is actually not a powerful explosive. The reaction rate is slower than most other high explosives, which means that an ANFO detonation generally does not cause the target to fragment into many smaller pieces. ANFO is best used for blasting rocks. It is placed in drilled holes, then detonated. Because the explosion is mostly confined inside the rock, the expanding gases cannot escape fast enough, and enough pressure can build up to blast the rock outward. This is called heaving power, and ANFO is good at blasting rock. A large amount of energy is released which forces the rock outward, but the explosion is not as fast as other explosives.
Two metric tons of plain ANFO (without certain additives that improve performance) detonating inside a truck does not even severely damage the trucks frame. Little or no metal pieces are blasted off, and the explosion only leaves a shallow dent in the metal.
C-4, which consists mostly of RDX with some added plasticizer, is much more powerful.
"Once we rolled a full bar into a pencil-thin string and girdled a tree with it, then set it off. The C-4 cut through the foot-thick trunk with ease."
A 5cm cube of C-4 is enough to completely destroy a segment of train rail track.
70g of C-4 easily blasts through a 0.6cm (quarter inch) steel plate.
Advanced Alternatives to Ammonium Nitrate in Compositions
Here is some advanced information, Ammonium Nitrate is certainly not the only possible solid explosive that can act as an oxidizer in a composition. Below is a list of several other obscure
salts, in order of how energetic they are, with the most energetic at the top of the list.
Hydroxylamine Perchlorate
Ammonium Dinitramide
Ammonium Perchlorate
Hydrazinium Nitroformate
Hydroxylamine Nitrate
Ammonium Nitrate
This list should give some idea about how energetic different cations and anions (positively and negetively charged ions) are relative to eachother. Generally, the more energetic a salt is, the more sensitive it is, with Ammonium Nitrate being extremely difficult to burn or detonate, and Hydroxylamine Perchlorate being very sensitive (almost dangerously so).
Here is some more information that is not seen many places online:
hydroxylamine perchlorate, hygroscopic solid
melting point between 87.5 and 89degC. Decomposes at 120degC. Drop height value of only 2cm, meaning very sensitive to impact. addition of small ammounts of hydroxylamine perchlorate to several propellents could roughly double their burning rates.
Some more information about other uncommon explosive salts that are net oxidizers:
hydrazinium perchlorate melts at 137degC.
hydroxylammonium nitrate melts at 48degC.
Addition of Sensitizers
For compositions, the best fuel additive to add into AN is hexamine di-nitrate. Hexamine di-nitrate (HDN) is fuel-rich, and is an ionic salt like AN, so if the two powders are finely crushed they can be much better mixed together than if other fuels had been used. This mixture would be on a very small scale, not quite a molecular scale like double salts, but almost. This means that the detonation velocity of an AN-HDN composition can be substancially higher than an AN-fuel mixture.
Hexamine di-nitrate, also referred to as hexamethylenetetramine dinitrate, (HDN) is an explosive by itself (containing both "fuel" positively charged hexamine ions, and "oxidizer" nitrate ions).
The molecular formula of HDN is C6H14N6O6 , which should indicate that it is overall fuel-rich. In other words, the decomposition products contain carbon and carbon monoxide that could be further burnt off by some other compound that is a net oxidizer, such as AN.
The molecular structure of HDN could also be expressed as (CH2)6N4*(2)HNO3. It should be noted that HDN is a very insensitive explosive, and although it is somewhat easier to detonate than AN, it still requires a fairly powerful blasting cap to be detonated. Mixing finely powdered HDN into finely powdered AN, will make the composition easier to detonate than AN alone, thus HDN can be considered a sensitizer.
During the preparation of HDN, if too much acid is used and it is too concentrated, it is possible that the hexamine may disproportionate and hydolyze into formic acid and methylamine nitrate.
Such products can nevertheless still be used to sensitize AN.
Chlorates should not be mixed with ammonium compounds. AN absorbs moisture from the air, and this water could dissolve both the AN and chlorate. Ammonium chlorate is much less soluble than sodium chlorate (normally however ammonium compounds are much more soluble) and can easily precipitate out as a solid. Ammonium chlorate is unstable, and can start to rapidly decompose in sunlight, the decomposition eventually initiating an explosion.
Perchlorates can be mixed with AN without risk. Ammonium perchlorate is more sensitive to detonation than AN, so presumably adding a perchlorate salt to AN could make it easier to initiate.
Using Acetone Peroxide with Ammonium Nitrate: Not a good idea!
Not only is acetone peroxide very unsafe, but it is also a poor initiator of other main charges since it is mostly an "entropic explosive" (most of the effective energy released is in the form of resultant gases that take up a larger volume, not heat)
Organic peroxides and ammonium nitrate compositions are much simpler to prepare, and use more readily available precursors, than any other improvised explosive.
Yet in terms of sensitivity, organic peroxides and AN compositions are at completely different extremes of sensitivity. Organic peroxides are one of the most dangerously sensitive types of explosives. The only explosives more sensitive are the ones that usually spontaneously explode for no reason soon after preparation. Organic peroxides have been described as several times more sensitive to friction than even nitroglycerin.
Ammonium nitrate compositions are the most insensitive (difficult to detonate) type of explosives. It requires a fairly powerful explosion for AN to itself detonate. AN compositions typically do not explode when shot with a rifle, or placed into a fire. For experimenters with improvised ingredients, it can be very difficult to get an AN composition to detonate. Components which act as semsitizers are often part of the composition, making it easier to detonate the AN. However, even with the addition of most types of sensitizers, the AN composition still requires a sufficient explosion to detonate.
Both organic peroxides and AN compositions give off much less heat when they explode than most other explosives. Most of the power of the explosion is from the formation of gas, which has a cooling effect as it expands. From one perspective, it could be stated that much of the energy from these explosives comes from the ambient (room temperature) heat in the solid explosives before they explode. These types of explosives are referred to as "entropic explosives".
Additives to Add Power
Do not try this, but mixing both some hydrazine and NM into AN makes the composition extremely powerful, and much easier to detonate (even adding 5% by weight hydrazine to AN makes it twice as sensitive). The nitromethane actually mixes with the hydrazine (it forms a sort of liquid "ionic compound", hydrazinium nitromethanate)
Alternatively, dimethyl hydazine is substancially better than plain hydrazine mixed into AN, this was one of the lesser known Astrolite variants. Of course, hydrazine compounds give off toxic vapor. Preparing dimethyl hydrazine from common substances is actually fairly easy, but you will have to find the procedure somewhere else.
Physical Safety
Actually never recommend putting explosives inside pipes for safety reasons. Hard sharp plastic fragments could be propelled out potentially hurting someone, usually the experimenter.
Power of Plain ANFO
Explosives are in many ways completely different from pyrotechnics. All too often those familiar with pyrotechnics think explosives are merely mixes of fuel and oxidizer. This is generally not true. Explosives have a much faster reaction rate than pyrotechnics, the combustion reaction in a mechanical mixture of two powders is limited by surface area, and the reaction will be much slower than two liquids mixed together, for example. Finely pulverizing the solid powders into small particles helps increase reaction rate, but can still never approach the reaction rate of compounds that contain both fuel and usable oxygen together in their molecular structures.
ANFO is actually not a powerful explosive. The reaction rate is slower than most other high explosives, which means that an ANFO detonation generally does not cause the target to fragment into many smaller pieces. ANFO is best used for blasting rocks. It is placed in drilled holes, then detonated. Because the explosion is mostly confined inside the rock, the expanding gases cannot escape fast enough, and enough pressure can build up to blast the rock outward. This is called heaving power, and ANFO is good at blasting rock. A large amount of energy is released which forces the rock outward, but the explosion is not as fast as other explosives.
Two metric tons of plain ANFO (without certain additives that improve performance) detonating inside a truck does not even severely damage the trucks frame. Little or no metal pieces are blasted off, and the explosion only leaves a shallow dent in the metal.
C-4, which consists mostly of RDX with some added plasticizer, is much more powerful.
"Once we rolled a full bar into a pencil-thin string and girdled a tree with it, then set it off. The C-4 cut through the foot-thick trunk with ease."
A 5cm cube of C-4 is enough to completely destroy a segment of train rail track.
70g of C-4 easily blasts through a 0.6cm (quarter inch) steel plate.
Advanced Alternatives to Ammonium Nitrate in Compositions
Here is some advanced information, Ammonium Nitrate is certainly not the only possible solid explosive that can act as an oxidizer in a composition. Below is a list of several other obscure
salts, in order of how energetic they are, with the most energetic at the top of the list.
Hydroxylamine Perchlorate
Ammonium Dinitramide
Ammonium Perchlorate
Hydrazinium Nitroformate
Hydroxylamine Nitrate
Ammonium Nitrate
This list should give some idea about how energetic different cations and anions (positively and negetively charged ions) are relative to eachother. Generally, the more energetic a salt is, the more sensitive it is, with Ammonium Nitrate being extremely difficult to burn or detonate, and Hydroxylamine Perchlorate being very sensitive (almost dangerously so).
Here is some more information that is not seen many places online:
hydroxylamine perchlorate, hygroscopic solid
melting point between 87.5 and 89degC. Decomposes at 120degC. Drop height value of only 2cm, meaning very sensitive to impact. addition of small ammounts of hydroxylamine perchlorate to several propellents could roughly double their burning rates.
Some more information about other uncommon explosive salts that are net oxidizers:
hydrazinium perchlorate melts at 137degC.
hydroxylammonium nitrate melts at 48degC.
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