Aluminum and "Gold"

[GoldRob]

I'd suggest that's gold especially with the copper barrier layer. Dissolving the Aluminium is not the way ahead though. Youre going to make a mess and lose a lot of your gold inside it.

When you say lose, because the gold will go into solution? or it will be a pile of very small particles in with the salt and aluminum? Thank for the help.

 

[Yggdrasil]

When you say lose, because the gold will go into solution? or it will be a pile of very small particles in with the salt and aluminum? Thank for the help.

It will be hiding in the salts.

 

[GoldRob]

It will be hiding in the salts.

I have probably done the worse thing I could have. Now I will just let let the particulate settle to the bottom. Recover most of the salt. By moving it to another bucket and let it dry. Should have done just one piece. I have most the other boards in another bucket. Should I save all the salt?

 

[Yggdrasil]

I have probably done the worse thing I could have. Now I will just let let the particulate settle to the bottom. Recover most of the salt. By moving it to another bucket and let it dry. Should have done just one piece. I have most the other boards in another bucket. Should I save all the salt?

These salts are not straight forward, it can create a muddy paste that do not dissolve easily.

 

[GoldRob]

These salts are not straight forward, it can create a muddy paste that do not dissolve easily.

Thanks for the info. I will pull what is left out tonight and start to decant as much of the liquid as I can and let it evaporate. Than deal with the mud. : (

 

[orvi]

That was a nice stash of scrap. Gold plated, I dealt with some quantity of this stuff in the past.

You will spend hefty amount of acid to dissolve the aluminium. It can be also done with lye, and that can be more accessible and cheaper in the end. But still prety wasteful.

But given the fact you have copper underplating, good soak in nitric will peel it off eventually.

Concerning the salt aproach you choose, the sludge would need to be acidified anyways to be processed. And it will be very messy :/

 

[anarxi]

Uh, but aluminum melts easily...
Or is it some kind of heat-resistant alloy?
What if you cut it into pieces and try to melt it?
will the copper-gold foil separate or will it all melt into a heap...

 

[Yggdrasil]

Uh, but aluminum melts easily...
Or is it some kind of heat-resistant alloy?
What if you cut it into pieces and try to melt it?
will the copper-gold foil separate or will it all melt into a heap...

Gold alloys with Aluminum and Copper, not sure that is a good idea.

 

[orvi]

Gold alloys with Aluminum and Copper, not sure that is a good idea.

definitly a bad idea since gold will alloy easily. And aluminium cannot be electrorefined in conventional way in aqueous solutions since it reacts.

 

[GoldRob]

Took a sample of the mud going to let this dry. Picked out some larger pieces that broke off. Did not let the salt eat the the pieces completely.

 

[Alondro]

Aluminum dissolves VERY well in vinegar, and forms highly soluble aluminum acetate, which is a very low toxicity salt. In fact, it's often used in many topical medicines for its anti-itch and astringent effects.

For this material, you would want to use ONLY vinegar with NO SALT. It will eat away the aluminum and some of the copper, but should not touch the gold at all in such a low acetate concentration. Gold(III) acetate is only commonly formed from the reaction of gold(III) hydroxide with glacial acetic acid.

The copper acetate is also low toxicity, and was used for centuries for its fungicidal effects, as well as for pigments.

So, if you can be certain this material has only aluminum, copper, and gold; then low-concentration acetic acid (vinegar) is the simplest and cheapest method to leave you with relatively clean gold foils.

 

[Alondro]

I should also mention that if you don't want to dump the aluminum acetate waste solution down the drain, you can simply boil the water away and the acetates will decompose into alumina (aluminum oxide, a fairly inert compound).

The copper acetate will still remain, and may be just enough give your alumina powder a pale greenish color.

Might be interesting to try making a corundum with it!