Sciencemadness Discussion Board
Not logged in [Login - Register]
Go To Bottom

Printable Version  
 Pages:  1  ..  21    23
Author: Subject: Exotic thermites & analogs
James Ikanov
Hazard to Self
**




Posts: 76
Registered: 12-7-2015
Location: Alaska
Member Is Offline

Mood: Zen

[*] posted on 31-12-2016 at 19:08


Something interesting I just read that may apply to those of you using MnO2 type thermites....

https://medicine.wustl.edu/news/low-levels-manganese-welding...


I'm not sure if it's relevant to everyone or even anyone but it seems like something worth throwing out there where it's visible for anyone it might effect.




“To do good work one must eat well, be well housed, have one's fling from time to time, smoke one's pipe, and drink one's coffee in peace” - Vincent Van Gogh
View user's profile View All Posts By User
tsathoggua1
National Hazard
****




Posts: 336
Registered: 8-1-2017
Location: Beyond the pale
Member Is Offline

Mood: Phosphorescent

[*] posted on 13-4-2017 at 13:37


Has anyone experience with Mn(OH)2-Mg or Mn(OH)2/Al thermites? Been wanting to reduce some manganese hydroxide using either Mg fine dust or have some <~30 micron Al. Is this known to be violent or explosive? because a slower burn is desired in order to trap the results in a crucible whilst burning and retain the Mn, the point of the exercise.

Likewise, with these reductants and colloidal SiO(H)2.
View user's profile View All Posts By User
PHILOU Zrealone
International Hazard
*****




Posts: 2845
Registered: 20-5-2002
Location: Brussel
Member Is Offline

Mood: Bis-diazo-dinitro-hydroquinonic

[*] posted on 14-4-2017 at 18:31


Quote: Originally posted by tsathoggua1  
Has anyone experience with Mn(OH)2-Mg or Mn(OH)2/Al thermites? Been wanting to reduce some manganese hydroxide using either Mg fine dust or have some <~30 micron Al. Is this known to be violent or explosive? because a slower burn is desired in order to trap the results in a crucible whilst burning and retain the Mn, the point of the exercise.

Likewise, with these reductants and colloidal SiO(H)2.

The idea to use hydroxides into Al or Mg thermites is for obvious reasons extremely dangerous...
-->hot burning composition (>2000°C) + water as product = explosion of H2O (gas) spreading burning red hot metal all over the place and at a relatively big distance...




PH Z (PHILOU Zrealone)

"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
View user's profile View All Posts By User
tsathoggua1
National Hazard
****




Posts: 336
Registered: 8-1-2017
Location: Beyond the pale
Member Is Offline

Mood: Phosphorescent

[*] posted on 16-4-2017 at 09:30


Decided to roast it, thanks for the quick tip.

Anyone ever done an MnO2 thermite? Question is, due to the reactivity of Mn, will it survive, and would a (lidded) carbon crucible survive the experience? and how difficult is it to ignite? I've always found bog standard Fe oxide/Al type thermites rather difficult to get going.

Mainly asking due to the rather odd reactivity of copper oxide thermites, Mn being a somewhat out of the usual range, I'd like some idea of its reactivity before initiation. The end goal is actually collecting the Mn, rather than simply a pyrotechnic display.

Would addition of a little sulfur to a small surface area suffice to allow initiation from the outside (assuming the lid is tightly clamped on, with a bit of disposable crap wood to avoid melting the clamp (these have copper plated steel end plates, ideally initiation from the outside of the crucible would be good, elsewise I'd have to initiate it with a piece of Li strip meaning gutting a battery (I've got some better quality Li, but thats kept in a sealed bag of inert gas, presumably argon, in a jar containing some anhydrous CaCl2 and Mg powder to absorb H2O and oxygen respectively, most of it already having been displaced with dry argon. And I'd sooner not open that, I'm saving it for the next time a large birch-benkeser reduction is on the menu, or something similar, so all 20-25g can be used at once, storage being a pain in the ass.

I find the foils in batteries work well for initiating thermites, and damned if I don't have a huge bag full of e-fag batteries that have gone down the shitter, so to speak. Damn things have a remarkably high attrition rate. Although at least when they fail charged they are good recycling material. (as if I haven't spent enough time filleting batteries of late, was up all night last night doing just that)



[Edited on 16-4-2017 by tsathoggua1]
View user's profile View All Posts By User
Bert
Super Administrator
*********




Posts: 1941
Registered: 12-3-2004
Location: Blasted Hellish frozen Northern wastelands
Member Is Offline

Mood: Negative, I am a meat Popsicle.

[*] posted on 16-4-2017 at 22:45


If you ignite an Aluminum/Manganese dioxide thermite in a sealed crusible, it will probably EXPLODE.

The Manganese comes off as a GAS. Not a well mannered liquid metal- LOTS of very HOT gas, you can use this reaction as a rocket fuel with an ISP similar to black powder.

There are descriptions of techniques that have been used by a member to collect Manganese metal from such reductions posted here, search a bit.




Boom.
The explosion removed the windows, the door and most of the chimney.
It was the sort of thing you expected in the Street of alchemists. The neighbors preferred explosions, which were at least identifiable and soon over. They were better than the smells, which crept up on you.
-Terry Pratchett, "Moving Pictures"

It is essential that persons having explosive 
substances under their charge should never 
lose sight of the conviction that, preventive 
measures should always be prescribed 
on the hypothesis of an explosion.

Marcellin Berthelot - 1892 
Explosives and their power - Page 47
View user's profile View All Posts By User
tsathoggua1
National Hazard
****




Posts: 336
Registered: 8-1-2017
Location: Beyond the pale
Member Is Offline

Mood: Phosphorescent

[*] posted on 17-4-2017 at 02:27


Did it in the open, and wasn't greatly surprised to find that there wasn't a collectible quantity of elemental manganese. I don't do pyro, can't afford to get clocked doing that stuff, the thermite rxn is more or less an exception, used for E.g cutting, welding, and harvesting metals from oxides.

MnO2/Mg proved too difficult to ignite on its own, but the mixture, sensitized with a little sulfur in a localized area (the idea being the thermate ignites the thermite with as little sulfur/sulfide contamination as possible) does indeed go off bloody fast. Hadn't quite realized HOW fast though. MnO2/Mg/S thermate goes off like flash powder and is sensitive enough to ignite with a blowtorch flame exposure for a second or two, yet MnO2/Mg (can't remember the mesh size, but fairly fine.

Another attempt made was pyrolysis of manganese formate and acetate in an argon-purged stoppered tube in the hope of forming something akin to pyeophorus of lead or pyrophoric iron nanopowder akin to the products of pyrolyzing the corresponding tartrates (didn't have any tartaric acid to hand so I went with the formate and acetate salts. Next, the ascorbate will be tried, Vit.C being a reducing agent might help, would be interesting to try anyway. As will the cutrate,

Acrid fumes were driven off under heating in the air of a sample, whilst a dark, tarry substance, doubtless generic organic residues from pyrolysis of the organic portion of the salt, but no luck, even when heated sufficiently to break the test tube (I've another order coming of test tubes and this one was intractably mucky so sacrificing it was fine,
View user's profile View All Posts By User
tsathoggua1
National Hazard
****




Posts: 336
Registered: 8-1-2017
Location: Beyond the pale
Member Is Offline

Mood: Phosphorescent

[*] posted on 17-4-2017 at 02:41


Interesting that people say PbO2/Al thermites are meant to be energetic, U dud use it in a thermite once, ignition with a strip of lithium foil in lieu of magnesium as a fuse, and it was decidedly sluggish, onlu a few sparks and a slow, dull red glowing reduction giving elemental lead
View user's profile View All Posts By User
Elemental Phosphorus
Hazard to Others
***




Posts: 123
Registered: 11-11-2016
Location: Is everything
Member Is Offline


[*] posted on 24-5-2017 at 16:07
Strange problem with MgAl-red iron oxide thermite


Today I ignited about 600 milligrams of thermite made with 200-325 mesh magnalium and red iron oxide (pottery grade, extremely fine, I can post a photo if necessary). Much to my surprise, it did not deflagarate like traditional Fe2O3/Al thermite, rather it deflagarated extremely fast (for thermite, slower than flash powder), and on analysis of the video the flash lasts ~8 frames. Can anyone provide insight as to why this happened? I mean, 4 of the frames are a completely yellow-white screen. That is simply not consistent with what I have seen of iron oxide thermite. Any comments? Thanks.
View user's profile View All Posts By User
ShotBored
Harmless
*




Posts: 5
Registered: 19-5-2017
Location: Montana
Member Is Offline


[*] posted on 24-5-2017 at 16:51


What was your ratio of mag-al to Fe2O3?
View user's profile View All Posts By User
Elemental Phosphorus
Hazard to Others
***




Posts: 123
Registered: 11-11-2016
Location: Is everything
Member Is Offline


[*] posted on 24-5-2017 at 17:42


250 milligrams of magnalium and 350 milligrams of red iron oxide.
View user's profile View All Posts By User
greenlight
International Hazard
*****




Posts: 503
Registered: 3-11-2014
Member Is Offline

Mood: Energetic

[*] posted on 24-5-2017 at 23:53


I have done some tests with magnalium thermite before and took photos.
I had a similar ratio to the one you list to start and it deflagrated very fast mainly throwing red hot metal all around and slightly charring what it was in contact with.
Results from testing in 5 gram amounts were:

2:1 Fe2o3:Mg/Al = Slightly slower but still too fast burning. Nearly no slag left.

3:1 Fe2o3:Mg/Al = Much slower burn rate 3 seconds) leaving some red hot slag.

4:1 Fe2o3:Mg/Al = Even slower burntime (5-6 seconds) leaving a lot of red hot slag behind.

I found it to be about perfect between the two last ratios. Here are two pictures of the tests midburn that I found. The left is the ratio similar to yours and the right is about 4g iron oxide to 1.2g Mg/Al.

[Edited on 25-5-2017 by greenlight]

2017-05-25 15.38.37.png - 2.8MB Screenshot_2017-05-25-15-43-00.png - 2.2MB

[Edited on 25-5-2017 by greenlight]




The only use for an atomic bomb is to keep somebody else from using one.
George Wald
View user's profile View All Posts By User
PHILOU Zrealone
International Hazard
*****




Posts: 2845
Registered: 20-5-2002
Location: Brussel
Member Is Offline

Mood: Bis-diazo-dinitro-hydroquinonic

[*] posted on 25-5-2017 at 00:40


Quote: Originally posted by Elemental Phosphorus  
Today I ignited about 600 milligrams of thermite made with 200-325 mesh magnalium and red iron oxide (pottery grade, extremely fine, I can post a photo if necessary). Much to my surprise, it did not deflagarate like traditional Fe2O3/Al thermite, rather it deflagarated extremely fast (for thermite, slower than flash powder), and on analysis of the video the flash lasts ~8 frames. Can anyone provide insight as to why this happened? I mean, 4 of the frames are a completely yellow-white screen. That is simply not consistent with what I have seen of iron oxide thermite. Any comments? Thanks.

Magnesium si more reactive than Aluminium so the mix ignites faster and easier...the activation energy is thus lower.

Magnesium burns brighter than Aluminium so your photo or video camera sensor did a (over)saturation of its sensor and had not the time to adapt for brightness.




PH Z (PHILOU Zrealone)

"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
View user's profile View All Posts By User
Elemental Phosphorus
Hazard to Others
***




Posts: 123
Registered: 11-11-2016
Location: Is everything
Member Is Offline


[*] posted on 25-5-2017 at 03:58


That makes sense, thanks. I was going to guess that since I had not previously dried the red iron oxide, it was a steam explosion. But that didn't really make sense, since there was a very bright flash, and the oxide didn't seem *too* wet. I'll post some freeze-frames later today. Anyhow, I'm glad I only made 600 milligrams, since I did not expect a fast deflagaration. I suppose that I can take away the lesson to always test any sort of pyrotechnics or energetic compositions in small quantities.
View user's profile View All Posts By User
PHILOU Zrealone
International Hazard
*****




Posts: 2845
Registered: 20-5-2002
Location: Brussel
Member Is Offline

Mood: Bis-diazo-dinitro-hydroquinonic

[*] posted on 25-5-2017 at 12:04


Quote: Originally posted by Elemental Phosphorus  
That makes sense, thanks. I was going to guess that since I had not previously dried the red iron oxide, it was a steam explosion. But that didn't really make sense, since there was a very bright flash, and the oxide didn't seem *too* wet. I'll post some freeze-frames later today. Anyhow, I'm glad I only made 600 milligrams, since I did not expect a fast deflagaration. I suppose that I can take away the lesson to always test any sort of pyrotechnics or energetic compositions in small quantities.

Yes prior small testing is a must not only once, but everytime a parameter changes...moisture, new ingredient or batch, different mesh, different temperature, different confinement,...

And when scaling up...it is a good idea to do it by slow increments for safety considerations...even a simple scaling up factor 2 has lead to casualities onto industrial plants or on lab reactions process...via unsuspected side-reactions with a lower minor thermodynamic kinetic at one scale but higher and major at double scale...




PH Z (PHILOU Zrealone)

"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
View user's profile View All Posts By User
Elemental Phosphorus
Hazard to Others
***




Posts: 123
Registered: 11-11-2016
Location: Is everything
Member Is Offline


[*] posted on 25-5-2017 at 13:26
Photos, as promised


Here are the photos, as I promised:

image.jpeg - 131kB image.jpeg - 164kB image.jpeg - 138kB image.png - 660kB
Edit: I chose to omit the entirely white frames since those don't really help.

[Edited on 25-5-2017 by Elemental Phosphorus]
View user's profile View All Posts By User
Dornier 335A
Hazard to Others
***




Posts: 198
Registered: 10-5-2013
Location: Northern Europe
Member Is Offline


[*] posted on 26-5-2017 at 01:57


There's another important difference between magnesium and aluminium: the boiling point. Al boils at 2470°C and Mg at 1091°C, which means that magnesium based thermites produce gas unlike aluminium based ones.
View user's profile View All Posts By User
kratomiter
Hazard to Self
**




Posts: 93
Registered: 30-9-2012
Member Is Offline


[*] posted on 6-7-2017 at 07:31
Magnalium/Sm2O3 thermite


Here is a photo of a magnalium/Sm2O3 thermite. It burns slowly with a strong white light light, leaving a surface of what seems Al/Mg/Sm oxide (it gets oxidized easily when exposed in the air) and samarium dust inside. Also it emits white fumes, maybe Samarium?

foto_no_exif.jpg.png - 1.7MB

[Edited on 6-7-2017 by kratomiter]
View user's profile View All Posts By User
 Pages:  1  ..  21    23

  Go To Top