How do you purify aluminum?

I want to know how to turn aluminum foil into aluminum powder. I have been told that aluminum foil is not pure aluminum, and I would like to know how to purify it.

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Prfesser6 years ago
Haven't tried it myself but my understanding is that foil may be ball-milled into flake aluminum.  It takes a lot of time and some kind of additive to keep the fresh powder from sticking to itself during milling.  And extreme caution is warranted when opening the milling jar.  There is likely to be a large amount of un-oxidized aluminum that will react when it encounters the atmosphere.  IOW the stuff could burst into flame when the jar is opened; allow oxygen to get to the aluminum gradually.
Kiteman6 years ago
No aluminium is pure, because the surface forms a thin, but impermeable, oxide layer within moments of being exposed to the air.

Even if you start with absolutely pure aluminium, your powder will end up with that same oxide layer over every grain, so the best thing to do is ignore it.

Can I ask what you need the powder for? Depending on the intended use, you may not need to go all the way to powder.
Tobor 2.0 (author)  Kiteman6 years ago
I need it for termite, I know it sounds like I'm going to go screw up something with it, but I assure you I only need it for scientific porousness
I'd be tempted to try dropping pieces into a running (dry) blender.

(I think you mean "thermite" and "scientific purposes")
Tobor 2.0 (author)  Kiteman6 years ago
What about ball milling it? would that work?
I've no idea, I've never used one.
Vyger6 years ago
Why foil? The foil will oxidize when you heat it and you will have mostly aluminum oxide. You can make your own fine filings just by using a fine tooth file and file it off of cans, edging or any other kind of aluminum, even old engine parts such as valve heads. To get powder would be very difficult without the right kind of tools. Not even sanding it down with a sander will get you powder. And true powder is much more dangerous as it can be easily inhaled which is a bad thing.
Tobor 2.0 (author)  Vyger6 years ago
Alumnium foil because that is the only thing I have