mgso4 as an oxidizer?

[Guest nathan_mb]

Hi, ummm firstly, is it magnesium sulfate, or sulphate? anyways. Now this may sound like a suspicious pyrotechnic question, but i assure you its not... ok well it is. I was searching through the internet for a smoke bomb, and came across two recipes, one using potassium nitrate and one using magnesium sulfate. Both were added to sugar and burnt. So my question is this: can anhydrous magnesium sulfate be used as an oxidiser? is it possible for mgso4 to donate oxygen to the reaction, just like kno3? after all, both contain oxygen.

 

thanx,

[YT2095]

it`ll not work, the SO4 bond is too strong to break down at simple `melted sugar` temperatures.

[Guest nathan_mb]

That being the case, would it be viable to put a magnesium strip or something in it, in order to attain the high temperature needed.

[YT2095]

the Mg strip wouldn`t react with the MgSO4.

you would get a side reaction with the sugar though, C12 H22 O11 + Mg = C + MgOH.

basicly the sugar would carbonise with the heat and give off water that water would react with the hot Mg to form it`s Hydroxide, there would be excess water too.

this reaction wont work in an enclosed area though, it`ll need the air to donate extra Oxygen.

[H2SO4]

id go with the KNO3 one. I have also seen many that are just simply black powder with the ingredients altered somewhat to produce a dense, white smoke. you can probaly get it here: http://www.wfvisser.dds.nl/compoDB.html

 

This webpage is the best for compositions.

[YT2095]

Ammonium Chloride is the prefered chem in some Military compositions, the heat breaks it down into Ammonia and Chlorine, it then recombines almost instantly as a dense white smoke.

[jdurg]

Ammonium Chloride is the prefered chem in some Military compositions, the heat breaks it down into Ammonia and Chlorine, it then recombines almost instantly as a dense white smoke.

 

Hmmm. I don't think that's chemically possible. (As ammonium chloride is NH4Cl, and ammonia gas is NH3 while chlorine is Cl2. There would have to be some H2 evolved as well, and that would react explosively with the chlorine). So I think it would be more apt to decompose into NH3 and HCl as I am 100% positive that those two will combine to give you a nice, dense white cloud.

[akcapr]

i guarantee that the heat casues the ammonium chloride to sublime[/u]

[H2SO4]

ammonium chloride sublimates?

[akcapr]

hell yes- get some and try it

[Silencer]

He wasn't disputing that the heat causes it to sublimate, he was disputing YT's statement that it recombines.

[akcapr]

oh. wen its sublimes it doesnt break apart i dont think...

[YT2095]

So I think it would be more apt to decompose into NH3 and HCl as I am 100% positive that those two will combine to give you a nice, dense white cloud.

 

agreed, my oversight, it`s been a long while since I was involved in any of that sort of composition, but basicly it still stands, Ammonium Chloride (and sometimes Zinc Chloride) are used in smoke pots/bombs.

 

and yes it does decompose, that`s why it`s not a good idea to use it indoors, as the HCl can be inhaled to form Hydrocloric acid in the lungs

[akcapr]

so when amonium chloride sublimes it actually decomposes and becomes hcl and nh3? and then that recombines into the solid fog. correct?

[YT2095]

yes, as far as I remember in training, that`s exactly what happens

[jdurg]

Actually, that wouldn't be sublimation then. That would be decomposition. NH4Cl sublimates. That means that it goes from a solid to a gas while bypassing the liquid phase. If it actually decomposed, then you wouldn't find a sublimation temperature in a CRC Handbook or MSDS. You'd find a decomposition temperature. What is most likely happening is that as the vaporized NH4Cl cools down, it cools down directly into a solid and therefore you see the fine particles of solid NH4Cl. I think that is what you are seeing, YT. It would look no different than if it was ammonia and hydrogen chloride combining. In either instance, you have a gas directly forming a solid.

[YT2095]

Jdurg are you 100% sure that it doesn`t decompose and re-combine, because I`m fairly certain that`s what I was taught, and that in fact it can be exploited due to this for certain area denial conditions!

 

damn my spelling sux!

[raivo]

NH4Cl surely decomposes and recombines although this process is so similar to sublimation that its not always important to know what exactly happens. Decomposition of NH4Cl can even be tested in simple experiment:

 

Heat small amount of NH4Cl to temp at which white smoke rises and put some piece of oxidised copper so that it gets in contact with that smoke. Copper immediatelly loses its oxide because HCl reacts with it. This is why NH4Cl is sometimes used at soldering work.

 

All ammonia salts decompose at rather low temperatures and i know of none that can be in liquid state under atmospheric pressure.

[akcapr]

wat other common solids sublime?

[raivo]

Iodine is most common. Another is that famous NH4Cl. Some more are NH4Br, NH4I, AlCl (only if its not hydrated), GeO. Almost every substance can sublime if heated in vacuum.

[BenSon]

Don't forget CO2 thats pretty common.

 

~Scott

[budullewraagh]

GeO and AlCl do not exist

[raivo]

Yes, AlCl does not exist. (it was meant AlCl3) But GeO exists. Its black powder, sublimes at aproximately 700C.

[BenSon]

\But GeO exists. Its black powder, sublimes at aproximately 700C.

Yes your right GeO does exist but it decomposes at around 700C not sublimes.

 

~Scott

[raivo]

I have book that says it sublimes. Maybe this is the same as with NH4Cl: Ge will immediately oxidise at 700C if it meets oxygen atoms. If it recombines to the same kind of oxide we are both right, but i am unable to test this.