megalomania
June 25th, 2003, 04:50 PM
OxYdiSer
A new voice
Posts: 12
From:
Registered: FEB 2001
posted March 01, 2001 11:58 PM
--------------------------------------------------------------------------------
I know I ask a lot of questions, but I'm just trying to get my head around HE's.
1) For all you chemically minded people out there : How does the addition of fuel oil (diesel) to AN sensitise this explosive? (try to explain without getting too technical)
2) Is prilled or powdered AN better for use in ANFO? I have read many posts on this subject and the general response seems to be split down the middle.
ALENGOSVIG1
Moderator
Posts: 766
From: Vancouver, Canada
Registered: NOV 2000
posted March 02, 2001 01:05 AM
--------------------------------------------------------------------------------
The deisel just acts as a fuel. Prills are better as they add air spaces and reduce density. Of you can use powdered Ammonium nitrate and add microspheres to do the same thing. With the powdered form, you dont have to wait for the fuel to soak into the prills.
------------------
technology is a wonderful servant, but a bitch of a master.
Explosives Archive
Bubba
Frequent Poster
Posts: 71
From:
Registered: DEC 2000
posted March 02, 2001 11:07 AM
--------------------------------------------------------------------------------
If you add #300 mesh alumnum to it it also increases the velocity. At least thats what I hear...
Anthony
Moderator
Posts: 2321
From: England
Registered: SEP 2000
posted March 02, 2001 02:55 PM
--------------------------------------------------------------------------------
I don't think the diesel acts as a fuel since the mixture doesn't deflagerate. It just sensitives the AN, he wanted to know exactly how/why it sensitives the AN.
Mr Cool
Frequent Poster
Posts: 991
From: None of your bloody business!
Registered: DEC 2000
posted March 02, 2001 04:24 PM
--------------------------------------------------------------------------------
It doesn't deflagrate, but the diesel will use up at least some of the extra oxygen in the AN molecule, thus making it more powerful. I'm not sure exactly how it sensitises it though.
ALENGOSVIG1
Moderator
Posts: 766
From: Vancouver, Canada
Registered: NOV 2000
posted March 02, 2001 11:22 PM
--------------------------------------------------------------------------------
Yes, that is what i meant by saying "fuel". But it doesnt use all excess oxygen, so AL or sugar can be added.
------------------
technology is a wonderful servant, but a bitch of a master.
Explosives Archive
wiredfreak
A new voice
Posts: 17
From: none of yuor fu**ing bissnes USA
Registered: JAN 2001
posted March 07, 2001 05:59 PM
--------------------------------------------------------------------------------
anyone know the good brands of Ammonium nitrate in the U.S.A ?
firebreether
Frequent Poster
Posts: 109
From:
Registered: NOV 2000
posted March 07, 2001 09:59 PM
--------------------------------------------------------------------------------
The reason AN is difficult to detonate pure is because of its stability. It is a very stable molecule. On a chemical level we would know this because of it's very negative heat of formation (enthalpy) value. When the enthalpy for a reaction is negative it gives off heat and increases the sensitivity becasue the reaction is more self promoting and violent. This is where it gets tricky. You would think because AN has a negative value it gives off alot of heat. WRONG. When a substance is used as a reactant its enthalpy switches making AN very positive as a reactant. So when it is by its self the detonation doesn't give off alot of heat and is hard to get going and keep going.
Another example- when you dissolve AN in water the enthalpy for the dissolved AN is not as negative so the whole reactions enthalpy is positive so it takes in heat making the water cold.
Back to the point. When you add a fuel- any reducer ( Powdered metals - Al, Mg, Organic material - oil, paper) the products have a higher negative enthalpy than before so the entire reaction has a more negative enthalpy. This makes it give off more heat and also sensitizes it. I think powdered metals are more efficient reducers so they increase sensitivity more than oil. Also Nitromethane is also like this which is why ANNM is easier to detonate and has a higher det. vel. than ANFO.
This only works with HE that give off Oxygen to use a fuel. With ones that have a negative Oxy balance, adding an oxidizer would probably boost power and sesitivity.
Just my thoughts. Finally putting those A++ chem tests to work. I knew I'd use thermochem again
Sorry if I confused you. But I think my logic is right.
A new voice
Posts: 12
From:
Registered: FEB 2001
posted March 01, 2001 11:58 PM
--------------------------------------------------------------------------------
I know I ask a lot of questions, but I'm just trying to get my head around HE's.
1) For all you chemically minded people out there : How does the addition of fuel oil (diesel) to AN sensitise this explosive? (try to explain without getting too technical)
2) Is prilled or powdered AN better for use in ANFO? I have read many posts on this subject and the general response seems to be split down the middle.
ALENGOSVIG1
Moderator
Posts: 766
From: Vancouver, Canada
Registered: NOV 2000
posted March 02, 2001 01:05 AM
--------------------------------------------------------------------------------
The deisel just acts as a fuel. Prills are better as they add air spaces and reduce density. Of you can use powdered Ammonium nitrate and add microspheres to do the same thing. With the powdered form, you dont have to wait for the fuel to soak into the prills.
------------------
technology is a wonderful servant, but a bitch of a master.
Explosives Archive
Bubba
Frequent Poster
Posts: 71
From:
Registered: DEC 2000
posted March 02, 2001 11:07 AM
--------------------------------------------------------------------------------
If you add #300 mesh alumnum to it it also increases the velocity. At least thats what I hear...
Anthony
Moderator
Posts: 2321
From: England
Registered: SEP 2000
posted March 02, 2001 02:55 PM
--------------------------------------------------------------------------------
I don't think the diesel acts as a fuel since the mixture doesn't deflagerate. It just sensitives the AN, he wanted to know exactly how/why it sensitives the AN.
Mr Cool
Frequent Poster
Posts: 991
From: None of your bloody business!
Registered: DEC 2000
posted March 02, 2001 04:24 PM
--------------------------------------------------------------------------------
It doesn't deflagrate, but the diesel will use up at least some of the extra oxygen in the AN molecule, thus making it more powerful. I'm not sure exactly how it sensitises it though.
ALENGOSVIG1
Moderator
Posts: 766
From: Vancouver, Canada
Registered: NOV 2000
posted March 02, 2001 11:22 PM
--------------------------------------------------------------------------------
Yes, that is what i meant by saying "fuel". But it doesnt use all excess oxygen, so AL or sugar can be added.
------------------
technology is a wonderful servant, but a bitch of a master.
Explosives Archive
wiredfreak
A new voice
Posts: 17
From: none of yuor fu**ing bissnes USA
Registered: JAN 2001
posted March 07, 2001 05:59 PM
--------------------------------------------------------------------------------
anyone know the good brands of Ammonium nitrate in the U.S.A ?
firebreether
Frequent Poster
Posts: 109
From:
Registered: NOV 2000
posted March 07, 2001 09:59 PM
--------------------------------------------------------------------------------
The reason AN is difficult to detonate pure is because of its stability. It is a very stable molecule. On a chemical level we would know this because of it's very negative heat of formation (enthalpy) value. When the enthalpy for a reaction is negative it gives off heat and increases the sensitivity becasue the reaction is more self promoting and violent. This is where it gets tricky. You would think because AN has a negative value it gives off alot of heat. WRONG. When a substance is used as a reactant its enthalpy switches making AN very positive as a reactant. So when it is by its self the detonation doesn't give off alot of heat and is hard to get going and keep going.
Another example- when you dissolve AN in water the enthalpy for the dissolved AN is not as negative so the whole reactions enthalpy is positive so it takes in heat making the water cold.
Back to the point. When you add a fuel- any reducer ( Powdered metals - Al, Mg, Organic material - oil, paper) the products have a higher negative enthalpy than before so the entire reaction has a more negative enthalpy. This makes it give off more heat and also sensitizes it. I think powdered metals are more efficient reducers so they increase sensitivity more than oil. Also Nitromethane is also like this which is why ANNM is easier to detonate and has a higher det. vel. than ANFO.
This only works with HE that give off Oxygen to use a fuel. With ones that have a negative Oxy balance, adding an oxidizer would probably boost power and sesitivity.
Just my thoughts. Finally putting those A++ chem tests to work. I knew I'd use thermochem again
Sorry if I confused you. But I think my logic is right.