Ammonium Nitrate for Rocket Fuel

[K@meleon]

Hi there,

 

I couldn't find anything about ammonium nitrate in the pyrotechnic thread, so decided to make a new thread.

 

I'm trying to make a small rocket engine using ammonium nitrate as fuel (easy to use, stable but powerful), but the problem is that I can only find desensitized ammonium nitrate.. Does somebody know how I could resensitize it?

 

Thanx

[woelen]

What do you mean with desensitized ammonium nitrate? In fertilizers it is mixed with some form of chalk (a mix of calcium carbonate and magnesium carbonate). It can be purified very easily, by dissolving it in water, letting the solid settle, decanting the clear liquid and slowly evaporating to dryness (at most 90 C, otherwise it may decompose violently, so be careful).

 

Ammonium nitrate, however, certainly is not the best chemical for pyro-purposes. It is very hygroscopic and compositions made with it are not very stable, due to this. It is hard to make a nice dry composition.

[YT2095]

and packing it into a tube such as a rocket engine could go DDT!

AN is lousey for pyro, you`de be better off converting it to a Potassium salt or Strontium or Barium.

[K@meleon]

What do you mean with desensitized ammonium nitrate? In fertilizers it is mixed with some form of chalk (a mix of calcium carbonate and magnesium carbonate). It can be purified very easily, by dissolving it in water, letting the solid settle, decanting the clear liquid and slowly evaporating to dryness (at most 90 C, otherwise it may decompose violently, so be careful).

 

Ammonium nitrate, however, certainly is not the best chemical for pyro-purposes. It is very hygroscopic and compositions made with it are not very stable, due to this. It is hard to make a nice dry composition.

 

By desensitized I mean that they mixed it whith some products so that you can't use is as oxidizer or explosive. The oxidizer logo also disappeared from their bags. But they still sell it under the very same name. Is the use of calcium carbonate and magnesium carbonate enough to reach that goal, or is there more to it?

 

How hygroscopic is very hygroscopic? Say if I make my mixture and keep it dry (in the garage) to use the same day, is it already too much?

 

I once read that it is was possible to make some sort of rocket fuel with a mix of ammonium nitrate and alcohol if I remember correctly. (Never went further then reading the recipe as I never found the correct stuff ) But they said it would make some sort of paste which would harden afterwards. (Spares me from the danger of packing everything in a tube with the risks associated.. )

But you guys are saying I'm better off with something else. Anything as easy as what I described?

[YT2095]

AN will puddle if left out in the open air at reasonable humidity.

 

also, are you SURE you`re not thinking about Ammonium Perchlorate here?

that stuff IS used extensively in rocket engines.

 

also, Sensitisers for AN means only one thing, Explosives, Amatol, Amanol, Anfo, Kinepak, Anpolover etc... all are Totaly useless as a rocket fuel.

[K@meleon]

Yeah, I'm quite sure. I'm almost certain the boosters of the space shuttle use ammonium nitrate mixed with aluminium powder.

Correct me if I'm wrong, but what you are saying is that AN is basically only good for explosives?

[K@meleon]

Crap. Just checked. You are absolutely right. The booster use Ammonium perchlorate..

 

Is ammonium perchlorate less hygroscopic then ammonium nitrate?

[YT2095]

it is indeed less hydroscopic

[woelen]

Unfortunately ammonium perchlorate is very hard to obtain. It is a regulated chemical, because of its strategic importance.

 

For the home-chemist/rocketry hobbyist, KNO3, mixed with suitable reductors, is the way to go, forget about ammonium perchlorate, I don't have it, and only few home chemists have it.

[encipher]

Woelen,

 

That's odd. The first Chlorate/Perchlorate I got was Ammonium Perchlorate. I still haven't used it all up either. Its fairly easy to obtain here in the US if you know the right suppliers. I didn't even pay hazmat shipping for it.

[K@meleon]

Unfortunately ammonium perchlorate is very hard to obtain. It is a regulated chemical, because of its strategic importance.

 

For the home-chemist/rocketry hobbyist, KNO3, mixed with suitable reductors, is the way to go, forget about ammonium perchlorate, I don't have it, and only few home chemists have it.

 

Well, thanks for the tip anyways. Will have to go with Potassium Nitrate then.. Will let you guys know when, and if it works out.

[Comandante]

I've heard ammonium nitrate can be used for propellants too but is highly recommended for experienced users.

 

I used KNO3 and it works fine, but as a beginner I found it takes some time to learn proper melting technique (if you use KNO3/sugar) and later making an engine out of that. As far as I remember I think KNO3 is hygroscopic too so if yours was out in the open you might want to dry it a bit as well. I once used relatively "wet" KNO3 and the rocket barely lifted off the ground a few meters, it was flying up amusingly slow

[YT2095]

for the record, I`m 100% against the use of AN as a propellant, it has a critical diameter of roughly 10cms, beyond that and it Will detonate!

you can boil water over a lump of burning C4, I wouldn`t do that either

[aamera]

U can use candle wax with nitrous oxide as oxidizer. Or u can use paraffin in presence of liquid nitrogen as rocket fuel

[YT2095]

U can use candle wax with nitrous oxide as oxidizer. Or u can use paraffin in presence of liquid nitrogen as rocket fuel

 

and between the paraffin and liquid Nitrogen, what do you suggest would be the reaction that takes place?

 

in fact, lets keep it REALLY simple, what would be the Oxidizer!?

 

and loose the crappy "txt msg" garbage, I`m sure English is on the curriculum! bad spelling`s one thing, abuse is another

[aamera]

and between the paraffin and liquid Nitrogen, what do you suggest would be the reaction that takes place?

 

in fact, lets keep it REALLY simple, what would be the Oxidizer!?

 

and loose the crappy "txt msg" garbage, I`m sure English is on the curriculum! bad spelling`s one thing, abuse is another

Sorry I could not edit it yesterday because my pc got stuck.

Liquid nitrogen is used to freez paraffin.as oxidizer flows over it, the surface of the paraffin melts to form a low-viscosity liquid layer that becomes unstable and forms waves that are easily pulled off the liquid surface as a spray of droplets that evaporate, mix and burn to produce thrust.

[TATER]

If i were you i would just use black powder in stick form.by turning it into stick form i mean dampening it and compressing it,that way the potassium nitrate will dissolve into the pores of the carbon thus making it stronger. forcing the propellant through a nozzle will also strengthen the rocket

[K@meleon]

Well, all sounds good. I'll have to try. Thanx