Sciencemadness Discussion Board

shock sensitive mixtures of KNO3

John paul III - 9-12-2020 at 14:11

Are there mixtures of KNO3 without additional oxidizers that can be easily ignited by shock, like by a firing pin?

B(a)P - 9-12-2020 at 15:41

White phosphorus is said to form an impact sensitive mixture with potassium nitrate, but that is very impractical.
I don't know for sure, but possibly red phosphorus, antimony sulfide or magnesium powder?
I am just guessing, any reason you want to know?

yobbo II - 9-12-2020 at 16:33


I once read in a book by Seymour Leck (if I have the spelin right) that a mixture of finely divided lead + KNO3 made a detonatable mixture. Believe it if you like. Seymour probably was not the most respected authority.

Yob

B(a)P - 9-12-2020 at 16:40

Quote: Originally posted by yobbo II  

I once read in a book by Seymour Leck (if I have the spelin right) that a mixture of finely divided lead + KNO3 made a detonatable mixture. Believe it if you like. Seymour probably was not the most respected authority.

Yob


You have got me curious to experiment with this, I will report back with what I discover.

Microtek - 10-12-2020 at 01:23

KNO3 and red phosphorus is friction sensitive enough to be set off by firm action of ceramic pestle on filter paper, so I would think it could also be initiated by impact.

phlogiston - 10-12-2020 at 04:49

IIRC 'yellow powder', being a mixture of potassium nitrate, potassium carbonate and sulfur molten together, is reported to be shock sensitive. Never tried this myself though, and it seems pretty dangerous to prepare, because you really need to melt the components together (just mixing the dry powders won't work), and it can detonate pretty violently in the molten state.

[Edited on 10-12-2020 by phlogiston]

Fulmen - 10-12-2020 at 05:32

IIRC the "secret" to yellow powder is the formation of polysulfides, so it might be possible to get some of the performance by first melting the sulfur and carbonate, then grind down and mix with the nitrate.

wg48temp9 - 10-12-2020 at 08:00

I was surprised that potassium carbonate would react with sulphur. Apparently it does in water or alcohol so I guess it would when melted together.

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Morgan - 10-12-2020 at 09:18

What is going on here in that like yellow powder, it seems to have an intermediate step before exploding and not just igniting or going off instantly with high heat?
https://youtube.com/watch?v=VzyWsdWfGUY

Fulmen - 10-12-2020 at 11:38

wg48: It most certainly does, I've done it on several occasions to prepare polysulfides for staining silver. I believe NaOH can be used as well.

John paul III - 10-12-2020 at 14:05

Quote: Originally posted by phlogiston  
IIRC 'yellow powder', being a mixture of potassium nitrate, potassium carbonate and sulfur molten together, is reported to be shock sensitive. Never tried this myself though, and it seems pretty dangerous to prepare, because you really need to melt the components together (just mixing the dry powders won't work), and it can detonate pretty violently in the molten state.

[Edited on 10-12-2020 by phlogiston]

Damn that's amazing if it works, and i will try making one gram of this

phlogiston - 10-12-2020 at 16:15

It is easy to find videos of the molten mixture detonating, so it definitely seems to 'work', eg:

https://www.youtube.com/watch?v=ZrYgRf-NuHs

but it'd be very interesting to see if you can melt it and cool it down before it has a chance to explode on you. There is not a lot of literature on the properties of this material after cooling/solidifying.

[Edited on 11-12-2020 by phlogiston]

Σldritch - 10-12-2020 at 23:19

I tried making nitrites that way because i read the polysulfides reduce the nitrate. I never got any though because it keept exploding even when far from optimal mixture so kt certainly works. :D

symboom - 10-12-2020 at 23:46

I wonder if a low melting solid or boric acid which is know to stabilize sulfur and nitrate mixtures would stabilize the mixture of yellow powder or urea and nitrite mix
I'd imagine ammonium acetate and potassium nitrite would also be dangerous due to ammonium nitrite intermediate formed.

[Edited on 11-12-2020 by symboom]

[Edited on 11-12-2020 by symboom]

Pyro_cat - 24-12-2020 at 17:35

My potassium chlorate from bleach mixed with sugar went off with a hammer shock.

DBX Labs - 24-12-2020 at 20:58

Haven’t seen this discussed much on other threads: Nitrite salts and Urea

Did a video on this a while back, the mix goes off on constant heating very similar to yellow powder. I melt a gram or two to the point where it was about to detonate (you can hear it start to ramp up in decomposition right before) and broke it apart when it cooled. 5 milligrams went off with a hammer strike on the anvil. Similar sensitivity to ETN.

DBX Labs - 24-12-2020 at 21:04

I read a while back somewhere that a mix of KNO3, Mg, and Guanidine Nitrate form a shock sensitive mix. I’d have to assume that the paper meant more so than the sensitivities of KNO3/Mg flash or Guanidine Nitrate on their own.

Morgan - 25-12-2020 at 08:36

Maybe if urea and nitrite were fine powders to start and intimately mixed and very slowly melted a slightly more uniform pre-reaction/idealized formation of the explosive would come about, walking it up rather than racing to the finish line? It's just a thought if there is a fragileness or more favorable condition.

Out of curiosity, does the typical yellow powder mix tolerate substituting nitrite for nitrate?

Nitrosio - 26-12-2020 at 00:35

KNO3 + K2S
KNO3 + P4S3
KNO3 + P + CS2

metalresearcher - 26-12-2020 at 10:11

KNO3 is less shock semsitive than KClO3, the latter forms much more shock sensitive mixtures. Hence mixing with sulfur is not rcommended and for that reason black powder contains KNO3 rather than KClO3.

Hey Buddy - 8-1-2021 at 11:37

Quote: Originally posted by John paul III  
Are there mixtures of KNO3 without additional oxidizers that can be easily ignited by shock, like by a firing pin?


"Easily"? I'm not aware of any, personally. BKNO3 is widely used in missiles as both grain ignitors and in det trains. Normally it is initiated by high voltage dielectric breakdown by purposeful failure of a dielectric material which then bumps up amps. Usually HV with caps, piezos or flux generators.

I'd imagine additives could make it firing pin sensitive. If you incorporated fluoropolymers and Mg, i think you might get something impact sensitive, possibly.

THV/Al or Mg comps are sensitive to photo initiation by a nikon camera flash and sensitive to detonation by impact if heat cured in pressed form

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