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roXefeller
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You didn't mention it in the youtube details, what was the composition that you demonstrated?
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DFliyerz
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2.93 parts Iron(III) Oxide, 1 part powdered aluminum (lots of aluminum oxide too, from the powdering proccess). I did a 76.3% Iron Oxide and 27.3%
Aluminum (logic, right?) mixture earlier, which burned a little more intensely, but both left lots of iron oxide over. You can see the instructions
where I got the first mixture here.
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Conor579
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I'm wondering if Thermite can be activated with the use of Sulfur.
[Edited on 22-8-2015 by Conor579]
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blogfast25
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What do you understand by 'activated'?
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iloveloli
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is it posible that i use PbO2/Mg and ZnO2/Mg to do thermite?
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blogfast25
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DO NOT DO THIS: these would be dangerous flash powders. And imagine spewing lead all over the place...
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crystal grower
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Hello, I want to make thermite from B2O3 + Al. The thing is that I dont have magnesium strips.
Is it possible to start this reaction only with potassium permanganate and glycerin?
Or would be sulfur with aluminium better ?
And second question, what granularities should I use if I dont want to make a flash powder (I want to collect elemental boron from it so explosion
would be bad).
Thanks for answer.
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blogfast25
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Quote: Originally posted by crystal grower  | Hello, I want to make thermite from B2O3 + Al. The thing is that I dont have magnesium strips.
Is it possible to start this reaction only with potassium permanganate and glycerin?
Or would be sulfur with aluminium better ?
And second question, what granularities should I use if I dont want to make a flash powder (I want to collect elemental boron from it so explosion
would be bad).
Thanks for answer.
|
There's a preparation in Georg Brauer, I think.
http://library.sciencemadness.org/library/books/brauer_ocr.p...
KMnO4 + glycerine should work OK.
These themites aren't flash powders, so not much to worry there.
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j_sum1
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| Quote: Originally posted by crystal grower | Hello, I want to make thermite from B2O3 + Al. The thing is that I dont have magnesium strips.
Is it possible to start this reaction only with potassium permanganate and glycerin?
Or would be sulfur with aluminium better ?
And second question, what granularities should I use if I dont want to make a flash powder (I want to collect elemental boron from it so explosion
would be bad).
Thanks for answer.
|
Al powder will work ok, but I recommend Mg powder for this one. That is because it allows you to recover the elemental boron afterwards simply by
dissolving the MgO in hydrochloric acid.
MrHomeScientist has a good video of the procedure.
Ignition is not too difficult. I used KMnO4/glycerine with a strip of Mg but the extra Mg was probably overkill.
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blogfast25
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https://www.youtube.com/watch?v=0QBCyOrjR2o
One problem with the reduction:
B2O3 + 3 Mg === > 2 B + 3 MgO
... is that the Enthalpy of Reaction is only - 531 kJ/mol of B2O3, not enough to reach the MP of MgO (2852 C), so element-slag
separation is quite poor.
[Edited on 10-2-2016 by blogfast25]
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Tdep
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I have tried B2O3 and Al thermite before and it really does not want to burn. I had real difficulty lighting it, and I had to heat boost it just to
get it to burn (I think I used sulfur.... it was two years ago). I was actually trying to get aluminium boride to try and produce diborane, and do a
similar reaction to the one where people make silane and watch it combust in air. But I got nothing on addition of the heat boosted thermite to acid.
The slag was ugly so I didn't bother recovering any elemental boron, not even sure if it was present.
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blogfast25
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| Quote: Originally posted by Tdep | | I have tried B2O3 and Al thermite before and it really does not want to burn. I had real difficulty lighting it, and I had to heat boost it just to
get it to burn (I think I used sulfur.... it was two years ago). I was actually trying to get aluminium boride to try and produce diborane, and do a
similar reaction to the one where people make silane and watch it combust in air. But I got nothing on addition of the heat boosted thermite to acid.
The slag was ugly so I didn't bother recovering any elemental boron, not even sure if it was present. |
Yes, I believe S + Al is used as a heat booster in Al/B2O3 thermites.
An interesting thing to try would be Al/B2O3, heat boosted with nitrate or chlorate and Al.
Excess Al then produces borides like AlB2 and AlB12, or so I've read. Never tried it myself.
Crude B, strongly heated with Mg probably also yields borides.
[Edited on 10-2-2016 by blogfast25]
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j_sum1
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That agrees with my findings. However, my goal was to dissolve the MgO in acid and leave boron powder and so element-slag separation was not really
an issue.
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blogfast25
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| Quote: Originally posted by j_sum1 |
That agrees with my findings. However, my goal was to dissolve the MgO in acid and leave boron powder and so element-slag separation was not really
an issue. |
This is where a boric oxide/Al reaction, boosted with nitrate or chlorate could be an interesting proposition: there really isn't much of a
problem to shoot past the relevant MPs. Just a basic guess would be that 0.2 mol of KClO3 + 0.4 mol Al (per mol of boric oxide) would be
enough to achieve about 2500 C, if not more.
Take the Enthalpy of the KClO3 booster reaction to be about - 1300 kJ/mol of KClO3, vaporisation of KCl included, so each 0.1
mol adds roughly - 130 kJ.
[Edited on 10-2-2016 by blogfast25]
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j_sum1
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That could turn out to be cleaner. Just a question. What kind of temperature must be reached before crystalline boron occurs?
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crystal grower
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Thanks for every answer.
In the brauer book is written that you need 110g of boron trioxide , 115g Mg etc. my question is if it is possible to make the reaction only with few
grams of each substance ??
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blogfast25
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| Quote: Originally posted by j_sum1 | | That could turn out to be cleaner. Just a question. What kind of temperature must be reached before crystalline boron occurs?
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Not sure. Obviously going over the MP would help.
| Quote: Originally posted by crystal grower | Thanks for every answer.
In the brauer book is written that you need 110g of boron trioxide , 115g Mg etc. my question is if it is possible to make the reaction only with few
grams of each substance ?? |
I'd ballpark at no less than 50 g of mixture.
[Edited on 10-2-2016 by blogfast25]
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woelen
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Be careful with homemade boron oxide derived from boric acid. From experience I known that boron oxide is surprizingly difficult to obtain in a pure
state. If you heat boric acid, then initially quite some water is split off, but removing the last amount of water is hard. H3BO3 can easily be
converted to something with empirical formula HBO2, but driving off the last remains of water to obtain real B2O3 requires very strong heating. Also
keep in mind that B2O3 is very hygroscopic and easily picks up water again. I once did the reaction with fine Mg-powder and when this is done with
partially dehydrated boric acid, then the reaction is very violent, much more so than when pure B2O3 is used. I do not have personal experience with
the Al-based reaction, but I can imagine that with this reaction a similar problem may exist.
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blogfast25
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| Quote: Originally posted by woelen | | H3BO3 can easily be converted to something with empirical formula HBO2, but driving off the last remains of water to obtain real B2O3 requires very
strong heating. |
Yes, that's correct and often overlooked.
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