Thread: Thermite reaction?

So I recently found very fine aluminium powder and Chrome Green (chromium oxide) paint pigments in a friend's art stash. I figured these could be used in a Thermite reaction, since I'm pretty sure Chrome Green is fairly pure chromium (III) oxide. The only tutorials online, however, are for iron oxide thermite, and the red pigments my friend has are all synthetic iron oxide, so they aren't the actual substance, so chromium oxide is the only metal oxide we have. Basically, I guess the only thing we need to know is the proportions to mix them in. I read that for aluminium and iron oxide it's 8 grams to 3 grams, but does anyone know what we should use for aluminium and chromium oxide? I couldn't find it after Googling. Thanks in advance.

Al + Cr2O3---->Al203+ Cr looks like 1 mole of each

and if you don't know what a mole is, you shouldn't be scewing around with chemicals.

Originally Posted by fizzlooney

2Al + Cr2O3---->Al203+ 2Cr looks like 1 mole of each

and if you don't know what a mole is, you shouldn't be scewing around with chemicals.

you need 2 moles of aluminum to 1 mole of oxide. just a minor oversight, fizz.

ops not on the ball today ,that's for sure.

So, 54g of aluminium powder per 152g of chromium oxide.

Or, roughly 1:3.

What are you planning to destroy?

Gee ,Drowsey, why do you think every pyrotechnic question has some neferious plot behind it? Exothermic reactions are fun, just have to control your fun.

Originally Posted by fizzlooney

Gee ,Drowsey, why do you think every pyrotechnic question has some neferious plot behind it? Exothermic reactions are fun, just have to control your fun.

Oh, yes, I just assumed that the 'fun' experiment would involve destroying something; it certainly would if it was me.

I didn't mean that it was going to be used for something dangerous and/or illegal; like that guy that wanted his recipe for acetone peroxide checking.

Haha, no, I don't plan to destroy anything, it's just that I've seen the reaction before, but it was during a science demonstration in a giant auditorium where the Luminol reaction looked like a tiny blue dot. Yeah, I was pretty far away. So I figured I would like to get a closer look. And while I'm at it, chromium oxide has the nice side-effect of producing chunks of pretty chromium instead of boring old iron. I'll put them away somewhere safe where they won't poison me.

So, it's a 2:1 molar ratio of chromium oxide to aluminium powder? I didn't even think of just taking the coefficients from the chemical equation. Durr. <_<

Now I've just gotta figure out how to measure the stuff. I don't own a balance. Bah, maybe I'll just refer to their densities and figure out how much I'll need based on volume.

Hmm, maybe I'll "accidentally" leave something I don't like directly under the surface where the Thermite reaction is being taken place on. Just as an efficient way of getting rid of it.

Oh, another concern I had. Many sources say you need magnesium ribbon to reach the necessary temperature to light the stuff. Is this true? I would have thought a simple butane torch would suffice, but if not, there's an excuse for me to buy some of that fun stuff too. I like the pretty lights it makes when it burns.

Thank you all for all of your help!

Originally Posted by drowsy turtle

like that guy that wanted his recipe for acetone peroxide checking.

He asked how to make it? I thought terrorists loved that stuff cause it was so easy to make. Hell, it's just a single-replacement reaction between two things in your medicine cabinet, isn't it?

Make sure you do it outside, with a bucket of water or two ready.

Originally Posted by Shadow

Oh, another concern I had. Many sources say you need magnesium ribbon to reach the necessary temperature to light the stuff. Is this true? I would have thought a simple butane torch would suffice, but if not, there's an excuse for me to buy some of that fun stuff too. I like the pretty lights it makes when it burns.

I'm sure it's possible without, but magnesium would be a lot easier

Originally Posted by Shadow

Originally Posted by drowsy turtle

like that guy that wanted his recipe for acetone peroxide checking.

He asked how to make it? I thought terrorists loved that stuff cause it was so easy to make. Hell, it's just a single-replacement reaction between two things in your medicine cabinet, isn't it?

He knew how to make it, but ironically wanted to make sure his recipe was 'safe'.