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Author: Subject: Exotic thermites & analogs
nitro-genes
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[*] posted on 20-11-2006 at 14:29


Wow, that was more violent than expected! :o I suppose the thermite burns a hole through the ice first that acts as a confiment for the rest of the formed steam. With liquid water instead of ice the results wouldn't be like that I guess... :)

Unlike that cheesy and staged British program Brianiac, german TV used to have some really interesting science shows. Especially the "Knoff Hoff show" was a great program...
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[*] posted on 20-11-2006 at 16:59


Quote:
Originally posted by nitro-genes
With liquid water instead of ice the results wouldn't be like that I guess... :)


"A phenomenon of considerable industrial importance in recent years is the vapor explosion, often referred to as a thermal or steam explosion. This phenomenon results from the extremely rapid heat transfer from hot liquid (e.g., molten metal) to cold liquid (e.g., water) when the two are contacted together. Sporadic explosions resulting from this phenomenon have been responsible for loss of life and property in industry for a number of years, and efforts have been made to understand the extreme violence of these interactions. It is not presently known exactly how these explosions are initiated. However, resultant effects of these interactions are dramatic, and substantial amounts of energy are released during such explosions." <a href="http://www.freepatentsonline.com/patents/us/521/5212343/5212343.pdf">US5212343</a>

"A aluminum liner, weighing 2.6 grams, was filed with 11 grams of water and sealed. The liner was placed inside of a well drilled in cold pressed pyrotechnic mix No. 1 CuO pellets. The pellets had been formed by cold pressing 74 grams of the mix No. 1 CuO. The pellets and liner were placed on a retaining stand and secured into place with the igniter plate and threaded rods. A Holex.TM. igniter was used to initiate the reaction of the pyrotechnic pellets. About 0.2 seconds after the initiation, an explosion occurred when the molten products of the pyrotechnic pellets and molten aluminum from the liner contacted the water." <a href="http://www.freepatentsonline.com/patents/us/437/4372213/4372213.pdf">US4372213</a>

[Edited on 21-11-2006 by Axt]
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chemoleo
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[*] posted on 20-11-2006 at 18:46


This is highly interesting.
I am particularly impressed about the effect of the molten metal/metaloxide onto the ice after the explosion, producing pyrotechnic effects in its own right.

This is something that can be definitly tried, particularly for members from Russia and Canada, or Antarctica, given 60 members are from there :P


I wonder what'd happen if it was done the other way round: a large thermite charge in a slightly larger beaker in water. Or how about methanol/ethanol, or, to get more fancy, things such as ammonium chloride, hydrazine chloride, ammonium persulfate etc? I bet a lot of experimenting could be done there.


[Edited on 21-11-2006 by chemoleo]




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[*] posted on 20-11-2006 at 19:48


Hell while we are at it lets use a frozen block of hydrogen peroxide. I have a feeling the iron oxide would decompose the frozen peroxide causing the thermite mix to fly into the air. The oxygen released from the peroxide and iron oxide would then combine with the Aluminum.

[Edited on 21-11-2006 by DeAdFX]




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nitro-genes
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[*] posted on 21-11-2006 at 02:30


Ahh, now I understand what is happening...:)

If you drop some water on a hot metal surface it will not flashboil at all since there is an insulating vapour layer layer between metal and water. I forgot that the metal is also a liquid in this case. With two liquids, the vapour layer is not stable and will dispers the liquid metal troughout the water, causing instant flashboiling of the entire water mass...

Replacing the water by some liquid fuel is the next logical step indeed.... :D

I'll look into it, I've plenty of aluminium powder left, I'm a bit short on the iron oxide though... :(
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[*] posted on 29-11-2006 at 00:25


Here's a bit of historical interest-

Aluminum as a Heating and Reducing Agent, by Dr. Hans Goldschmidt and Claude Vautin
http://pyrobin.com/files/thermit(e)%20journal.pdf

(This is from 1898, before Aluminum became a cheap metal)
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[*] posted on 18-12-2006 at 11:33


The other day I decided to try to use thermite to remove a tree stump. I used probably about 2Kg of thermite (Fe3O2) for this. And against my better judgment I threw in some Teflon power/Al mix. Fortunately there weren’t any repercussions from any Fluorine gas. The experiment as a whole failed, the stump remained largely unchanged, and actually, some bits of paper were left over after the reaction. But if you wanna see a video of it, its here http://video.google.com/videoplay?docid=4864739774767110399&...

(We put a tire rim around the stump and some boards to protect my mom's plants.)




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[*] posted on 18-12-2006 at 22:00


Why not do as farmers do and drill holes, soak it with nitrate solution, and later add some fuel and light it?
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[*] posted on 20-12-2006 at 15:56


Well to be perfectly honest I was just looking for a good excuse to use some thermite. Thats what we'll probably end up doing now that the thermite didn't work out. Thanks anyway for the suggestion.



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[*] posted on 20-2-2007 at 08:15


Quote:
Originally posted by farmisist
Well to be perfectly honest I was just looking for a good excuse to use some thermite.

Thermite is good for puncturing or welding metals, but isn't magicaly capable of doing similar things to wood, concrete or even paper. There were a number of WWII era government tests done on document destruction mechanisms for safes, thermite was not effective... Bricks of Sodium nitrate and coarse Magnesium were eventually used, as I recall. And even that wasn't outstandingly effective if there were thick piles of papers. Cellulose is a good insulator!
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[*] posted on 2-4-2007 at 22:16


Alright, I have my ingredients.

5lb Al
3lb Zn
1lb CuO
1lb Cu2O
1lb V2O5

How do I find these stoichiometric ratios? It's been a LONG time since I was in a chemistry class, and my next one isn't until fall semester. Really, I've forgotten a hell of a lot.
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[*] posted on 2-4-2007 at 23:01


Even wikipedia can help you there. The oxides are your oxidizers and the two pure metals are fuels. I don't think Cu2O will get you much since it is a lower oxidation state. V2O5 is pretty toxic as well, so be careful with it. The aluminum will do a much better job than the zinc for the reactions. The CuO will go off like flash powder if it is fine enough.....avoid the plume of vaporized copper and alumina and subsequent metal fume fever. Assume that you are going all the way to metal with the oxidizer...so, CuO -> Cu. For every mole (measurable quantity, just use wikipedia or a periodic table) of CuO, you need to use up a mole of oxygen atoms. Aluminum forms the oxide Al2O3, so two moles of aluminum will reduce 3 moles of copper (II) oxide completely. This means that for every mole of CuO, you need to mix in 2/3 of a mol of aluminum. Looking up the numbers, 79.5g of CuO need 18g of aluminum powder added. ~100g of such a violent thermite is probably an invitation for the cops and/or a hospital visit for the first experiment. Scale down to a few grams. The V2O5 would be very nice for making Vanadium metal if you keep an element collection.



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[*] posted on 3-4-2007 at 01:47


Quote:
Originally posted by egloskerry
How do I find these stoichiometric ratios? It's been a LONG time since I was in a chemistry class, and my next one isn't until fall semester. Really, I've forgotten a hell of a lot.


UnintentionalChaos has posted the correct information but I'm going to speak to you like you're mentally challenged for a moment to make sure you understand the theory.

Because stoichiometric ratios are concerned with the proper number of atoms reacting and because lab equipment measures mass rather than atoms, it is inconvenient that all atoms do not weigh the same. Thanks to the periodic table we are able to determine the weight of a set amount of atoms (the mole). 1 mole = 6.022 x 10<sup>23</sup> units, by the way. Anyhow, 1 mole of copper atoms does not have the same mass as 1 mole of aluminum atoms or 1 mole of oxygen atoms. The mass of a mole of a given type of atom is found on the periodic table underneath the symbol.
Copper has a molar mass of 63.54 grams per mole.
Oxygen has a molar mass of 16 grams per mole.
Aluminum has a molar mass of 26.98 grams per mole.

To determine the amount you need of each, start with a balanced equation.

3CuO + 2Al --> Al<sub>2</sub>O<sub>3</sub> + 3Cu

Simply, 3 molecules of CuO react with 2 molecules of Al to form one molecule of Al<sub>2</sub>O<sub>3</sub> and 3 molecules of Cu. Therefore, 3 moles of CuO react with 2 moles of Al to form one mole of Al<sub>2</sub>O<sub>3</sub> and 3 moles of Cu. Great! Or at least it would be great if you had a scale to measure the number of atoms in a pile of CuO. Fear not, you likely possess a scale that can measure mass so we can figure out the proper ratios with a little bit of math.

One mole of CuO weighs the same as one mole of Cu + one mole of O. Three moles of CuO, then, weighs 3 * (63.54 + 16) = 238.62 grams.
Two moles of Al weighs 2 * 26.98 = 53.96 grams.
The ratio then is 238.62 grams of CuO for every 53.96 grams of Al.
This is roughly 9:2 by weight.




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[*] posted on 3-4-2007 at 02:10


Quote:
Originally posted by DeAdFX
Hell while we are at it lets use a frozen block of hydrogen peroxide. I have a feeling the iron oxide would decompose the frozen peroxide causing the thermite mix to fly into the air. The oxygen released from the peroxide and iron oxide would then combine with the Aluminum.

[Edited on 21-11-2006 by DeAdFX]


It might almost be worth the cost of the reagents to see a Ag<sub>2</sub>O and Al thermite dripping molten silver into a beaker of concentrated peroxide :D

The silver thermite reaction alone would be almost twice as exothermic as the Fe<sub>2</sub>O<sub>3</sub> variety and I expect silver would do a much better job of decomposing the peroxide than iron would.

[Edited on 3-4-2007 by Levi]




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[*] posted on 3-4-2007 at 11:34


I imagine silver oxide will be fairly hard to get. Expensive, too. That V2O5 was 13$.

The scale is forthcoming. I'm still pricing them.
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[*] posted on 3-4-2007 at 11:43


There are some sellers of AgNO3 and Ag2O on ebay.. Their prices are quite nice in comparison to the other resellers of overly priced transition metal chemicals.
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[*] posted on 3-4-2007 at 11:59


Can't seem to find any.

I am getting my camera this week, so I'll be sure to videotape all these reactions.
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[*] posted on 4-4-2007 at 21:22


Quote:
Originally posted by UnintentionalChaos
I don't think Cu2O will get you much since it is a lower oxidation state.

Actually, Cu2O does give off a very decent thermite reaction.
Cu2O thermite is not as 'vigorous' as CuO thermite (CuO thermite can be VERY reactive), but it still is very much comparable to Iron Oxide thermites in terms of the reaction it produces (from my experience).

In doing a Cu2O thermite reaction, I was left with a very nice lump of pure Cu metal in the end.
Performing the same reaction with CuO would leave me with virtually nothing in the reaction vessel since all the products were vaporized / thrown out during the reaction.
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[*] posted on 5-4-2007 at 12:58


I'm guessing I use Mg ribbon to light these different compositions? I got a good deal on 75ft of it for just this purpose. It works well for Fe thermite but I want to make sure it'll work with this, too.

According to wikipedia, silver oxide decomposes when exposed to light.

Alright, I worked everything out. I scaled them all down to be about 50g total. Everything is rounded to a tenth of a gram.

3CuO + 2Al -> Al2O3 + 3Cu
3Cu2O + 2Al -> Al2O3 + 6Cu
3V2O5 + 10Al -> 5AlO3 + 6V
CuO + Zn -> ZnO + Cu
Cu2O + Zn -> ZnO + 2Cu
V2O5 + 5Zn -> 5ZnO + 2V

3CuO + 2Al -> 39.8 + 9
3Cu2O + 2Al -> 42.9 + 9
3V2O5 + 10Al -> 34.1 + 16.9
CuO + Zn -> 26.5 + 9
Cu2O + Zn -> 35.8 + 6.8
V2O5 + 5Zn -> 18.2 + 32.7

[Edited on 6-4-2007 by egloskerry]
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[*] posted on 6-4-2007 at 02:44


How easily ignitable the mix is depends heavily on particle size. If the particle size is the same for all mixes then I expect any method capable of initiating iron thermite will also initiate the more exotic blends but I'm only guessing here. V<sub>2</sub>O<sub>5</sub> is beyond me but if any of the afore mentioned is doomed to failure I imagine it is the vanadium / zinc mix but this is just a hunch because I couldn't find any thermodynamic data for V<sub>2</sub>O<sub>5</sub> although one site did say that vanadium metal is usually produced by reducing the pentoxide with calcium--of course calcium is considerably more reactive than zinc. Particle size and proper ratio will be key.



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[*] posted on 6-4-2007 at 08:39


The Al is somewhere around 600 mesh, the Zn is 300. I'm not sure about the others because I don't have them yet. I believe they were shipped on monday, so I should have them soon. They're in massachusetts.

[Edited on 6-4-2007 by egloskerry]
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biggrin.gif posted on 7-4-2007 at 09:00
Commercial Niobium Metal & its alloys


Some months ago, my school did a excursion with some students (including i :D) to another city where stay 2 big firms of minning industry. one of phosphate prodution for fertilizers, and another of niobium prodution.
the second , has the BIGGEST niobium mine and prodution in the world. (english version: http://www.us.cbmm.com.br/ ) and can produce (estimated) very easily bulk quantities of niobium metal for at least 300 years!
first we go to mines (all at soil surface, neither at subsoil), and after to prodution (metallurgical) plants( http://www.us.cbmm.com.br/english/sources/mine/operat/f_oper... see "Standard Grade Ferroniobium Production" ) and to a big lab of researches of niobium uses and anothers things.
i'm still quite wondered with the live vision of the big eletric arc furnace of Nb/Fe alloy production . my colleague take in this moment some photos..
below, the photos:

(note the aluminium sparks going out of the molten Ni-Fe : .. one of the most beautiful things )

[Editado em 12-4-2007 por Aqua_Fortis_100%]

fotos 024.jpg - 88kB




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[*] posted on 7-4-2007 at 09:25


This photo below is after the molten alloy go out of the furnace and stay on metal suports on a small "rail" for transport to another place of the plant.

in the conferences room of the firm (CBMM), a metallurgical engineer and a mine engineer are in this , explainning to the students all of the mine and processes.. the metallurgical eng. explained which the Al powder (unfortunately he not said the mesh grade) are mixed with Nb2O5 and the desired amount of iron (though he not said if this iron is in the form of Fe or Fe2O3) and initiated and keep by eletric arc, and then the molten alloy is collected below the furnace. i asked about details, and he says which there are another methods for small scale and researche and others furnaces for producing anothers alloys.
the CBMM also, sell the niobium oxide for other purposes.
my school planning to do another excursion with others teams of students, after holidays, and i think in will ask my teacher to see if she can get small amounts of Nb2O5 just for "souvenir" ehehe, because its very probably which not sell small amounts, only big.
if i get this i will try make a different thermit.. i know which this thermite not auto sustain it self, so i can add small amounts of Fe2O3 to see the progress.. what about this?


[Editado em 12-4-2007 por Aqua_Fortis_100%]

fotos 026.jpg - 110kB




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[*] posted on 7-4-2007 at 10:59


Mind uploading those pictures to an internet server, mmm?

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[*] posted on 11-4-2007 at 20:00


how, finally ,i think, i turn able to upload this photos..was quite difficult to me editing these photos ,since original size was MUCH larger to put here without irritating members..

12AX7 , thanks to advise me.

i really like to try this if my teacher will got a sample to my..
anyone has made mad experiments with Nb2O5?

edit: ( i remember that when in the lab i asked (with description) to the firm chemist why i cann't use some Nb2O5 in experiments as catalyst in the production of SO3 instead of V2O5, then he said anything as the resistance of heat(necessary in the catalysis) which the Nb2O5 offer without decreasing in performance without decreasing greatly in performance, compared to V2O5. Proceed this information?
i hate myself by not ask to he some sample of Nb2O5 (of course!) and more detailed info about thheir reaction with aluminium , chemistry and their metallurgy.

[Editado em 12-4-2007 por Aqua_Fortis_100%]




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