KNO3 - Aluminum flash powder equation.

[DubaiAmateurRocketry]

Guys whats the equation for KNO3 and Aluminum ? without sulfur ?

 

We all know this from wikipedia

 

2 KNO3 + 4 Al + S → K2S + N2 + 2 Al2O3

 

 

But what about KNO3 and Aluminum Alone ? I guess 2KNO3 + 2Al = 2K + N2 + 2Al2O3 ?

 

And if this is the true reaction, then the mix shall be according to weight.

 

 

79 % KNO3

21 % Aluminum

[Oinikis]

Potassium metal is way too reactive to be alone like that. I think without sulfur it would form potassium oxide (not sure maybe potassium aluminate). In my opinion it would be more like this:

6 KNO3 + 10Al ---> 3 K2O + 3 N2 + 5 Al2O3

So about:

KNO3 69%

Al 31%

But i think one with sulfur would burn way better, becouse sulfur lowers ignition temperature, so increases the speed.

[DubaiAmateurRocketry]

Potassium metal is way too reactive to be alone like that. I think without sulfur it would form potassium oxide (not sure maybe potassium aluminate). In my opinion it would be more like this:

6 KNO3 + 10Al ---> 3 K2O + 3 N2 + 5 Al2O3

So about:

KNO3 69%

Al 31%

But i think one with sulfur would burn way better, becouse sulfur lowers ignition temperature, so increases the speed.

 

Since K2O decomp at around 350 degree, which the combustion is well over 1000 degree celsius, K2O will become K, K, and O so it becomes gas right ?

 

Also, do u know at what temperature does KNO3 and AL burns at ?

[Oinikis]

well, maybe not K2O is formed i do not know, but potassium, i don't think it will just be metal, do you know even what substance potassium is? when freshy cut with a knife (it's soft) i tarnished with an oxide layer very quickly, and react explosively when exposed to water. I think the best option would be to use flash with sulfur, it's realy easy to get some, look at gardening or hardware stores. if you really really want to get perfect ratio, ask someone, who is good at chemistry (mumbles). but i still think, one with sulfur would be faster. anyway, what for you want to use flash powder? i try to avoid that stuff. Edited February 23, 2013 by Oinikis

[DubaiAmateurRocketry]

well, maybe not K2O is formed i do not know, but potassium, i don't think it will just be metal, do you know even what substance potassium is? when freshy cut with a knife (it's soft) i tarnished with an oxide layer very quickly, and react explosively when exposed to water. I think the best option would be to use flash with sulfur, it's realy easy to get some, look at gardening or hardware stores. if you really really want to get perfect ratio, ask someone, who is good at chemistry (mumbles). but i still think, one with sulfur would be faster. anyway, what for you want to use flash powder? i try to avoid that stuff.

 

Ok i need a burn rate, not too fast, but high temperature, for my rocket engine's igniton, i want a burn rate around 5-10cm per sec.

[NightHawkInLight]

Potassium nitrate does not react quickly at all with aluminum alone in my experience. Sulfur is necessary.

[Oinikis]

Ok i need a burn rate, not too fast, but high temperature, for my rocket engine's igniton, i want a burn rate around 5-10cm per sec.

You want to use it for rocket ignitors? i think BP will do the trick. also what fuel are you using?

[Mumbles]

I'm assuming you're getting your information from Wikipedia. That is not a particularly good chemistry resource. It is full of incorrect and misleading information. It's always good to check the sources they reference if included.

 

Potassium oxide can be made to decompose around 350-400C. Under an ultrahigh vacuum it forms potassium peroxide and potassium metal at this temperature. At atmospheric conditions, who really knows. The final products are almost certainly not any potassium metal. It's possible to be formed transiently. My best guess would be a mix of various potassium oxides, aluminates, and probably some nitrogen containing things.

 

For ignitors however, it probably doesn't matter if you're close to a stoichiometric mix. There are some thermitic mixes that are often used for ignitors.

[DubaiAmateurRocketry]

I'm assuming you're getting your information from Wikipedia. That is not a particularly good chemistry resource. It is full of incorrect and misleading information. It's always good to check the sources they reference if included.

 

Potassium oxide can be made to decompose around 350-400C. Under an ultrahigh vacuum it forms potassium peroxide and potassium metal at this temperature. At atmospheric conditions, who really knows. The final products are almost certainly not any potassium metal. It's possible to be formed transiently. My best guess would be a mix of various potassium oxides, aluminates, and probably some nitrogen containing things.

 

For ignitors however, it probably doesn't matter if you're close to a stoichiometric mix. There are some thermitic mixes that are often used for ignitors.

 

I can not get sulfur or ap or an since the place where i live bans it, so what do you think i can make for a good ignitor powder for my motors. i want not too fast of a burn rate, around 5-10cm per sec would be good, i made match powder which it burns at 20cm per s which i can accept but griding that small piece of match to get a whole thing to ignite a rocket is a joke, i wana try some sulfur less black powder or any thing. i wanted to try this recently.

 

70% kno3 20% charcoal and 10% aluminum.

[Mumbles]

If both AP and AN are banned in your area, how are you having any trouble at all igniting a rocket? It really sounds like you're thinking way too much into this. If a match composition will light your mix, sulfurless BP will almost certainly also do it. Adding in some aluminum should pretty much ensure it.

 

You keep talking about burn rate for ignitors. Are you actually looking to make some sort of delay fuse?

[DubaiAmateurRocketry]

If both AP and AN are banned in your area, how are you having any trouble at all igniting a rocket? It really sounds like you're thinking way too much into this. If a match composition will light your mix, sulfurless BP will almost certainly also do it. Adding in some aluminum should pretty much ensure it.

 

You keep talking about burn rate for ignitors. Are you actually looking to make some sort of delay fuse?

 

Oh im just asking for a burnrate of sulfurless black powder, or sulfurless black powder with aluminum. cus i have a good fine powder aluminum and don't wana waste them testing the burn rate.

 

Also i dont have the good type of trees for charcoal, i have palm trees and cactus, is sugar charcoal good ?

[Oinikis]

sugar charcoal, no, it's not good, becouse it's almost entirely element carbon, and in charcoal you get various carbon hydrates, whitch are very important. If you have only palm and cactus, you should try using various vines, i've heard some of them are good, anyway, it doesn't hurt to try. Could you tell us, what rockets, and fuels you want to ignite, and are you going to make some pyrotechnical delay, or electric ignitor?

[DubaiAmateurRocketry]

sugar charcoal, no, it's not good, becouse it's almost entirely element carbon, and in charcoal you get various carbon hydrates, whitch are very important. If you have only palm and cactus, you should try using various vines, i've heard some of them are good, anyway, it doesn't hurt to try. Could you tell us, what rockets, and fuels you want to ignite, and are you going to make some pyrotechnical delay, or electric ignitor?

 

My propellant is RNX. I will try some random normal tree and palm tree lol.

 

68% KNO3

25% Epoxy resin

7 % Aluminum powder.

[BlastFromThePast]

I've had some success with using vines as Oinikis mentioned. I'm really not sure what kind they are, one is a very pale white and it has very thin papery bark and the other is a very generic looking vine, very curly. I know this doesn't help much but what I'm trying to say is don't rule out the vines,they just might surprise you!!

[FlaMtnBkr]

You don't have hardware stores that sell lumber? Go to a construction site and look for wood scraps. What about animal bedding? Maybe some type of wood shavings are used? There has to be some type of wood, somewhere.

 

Why do you need the burn rate? And how are you measuring it? Compressed or a loose powder? I don't think anything will burn that fast if compressed. If a loose powder the rate will most likely depend on your testing method and how much composition there is per length.

 

I would be curious how you are making these 'igniters'?

 

I agree, you are making things too complicated.

Edited March 2, 2013 by FlaMtnBkr

[Jeffdyjeff]

 

I can not get sulfur or ap or an since the place where i live bans it, so what do you think i can make for a good ignitor powder for my motors. i want not too fast of a burn rate, around 5-10cm per sec would be good, i made match powder which it burns at 20cm per s which i can accept but griding that small piece of match to get a whole thing to ignite a rocket is a joke, i wana try some sulfur less black powder or any thing. i wanted to try this recently.

 

70% kno3 20% charcoal and 10% aluminum.

[Jeffdyjeff]

Why dont you just make sugar rockets? They work beautifully and dont require sulfur or any other exotic chemical. Also, if you can acquire any muriatic acid (for swimming pools) or sulfuric acid drain cleaner, you can use that and kno3 to make nitric acid and make nitrocellulose.

[SharkWhisperer]

Why dont you just make sugar rockets? They work beautifully and dont require sulfur or any other exotic chemical. Also, if you can acquire any muriatic acid (for swimming pools) or sulfuric acid drain cleaner, you can use that and kno3 to make nitric acid and make nitrocellulose.

Why you are lighting up a novice/naive 7-year-old post, started by a guy that hasn't been onsite for 7 years, for your third post on APC is beyond my comprehension.

 

You are welcome, of course, but perhaps introduce yourself and tell us a bit about your experience and your aims?

Edited December 6, 2020 by SharkWhisperer