Non-Chemical first timer: few questions

[daveshea]

First, thanks to everyone here for such a great resource!

I am using the Muriatic Acid/Peroxide method for processing fingers from old PC cards I have. So far, so good.

Once they are all stripped and I have filtered out the gold flakes, what is left?

In other words, what is the remaining liquid, and what can I do with it? I understand copper is dissolved in the solution, but is there anything else, like silver?

If it is only copper, how do I drop it out?

Thanks in advance for your help!

-David

 

[Noxx]

I don't think you will have silver in solution... This is mostly copper.

 

[lazersteve]

Here's the link to the disposal info:

AP Disposal

Sorry no silver normally.

Steve

 

[daveshea]

thanks for the replies...

Another question: If I remove flatpaks from circuit boards, do I then smash them apart to expose what I assume is gold inside of them? Can I then process these using the same muriatic acid/peroxide process?

-David

 

[lazersteve]

David,

Yes you will need to grind them to a very fine powder. I have no real data on the yields from the flatpaks yet, but certain ones are loaded with visible gold. When I find a particular type that is rich in content I always try to keep those types separate from the others.

The fine powder from the chips should be treated with dilute nitirc or HCl in an initial base metal stripping stage, followed by a gold leaching stage with your favorite method. The chips may contain some PGM's as well.

You will need a load of the low grade ics to get any real results.

Steve

 

[daveshea]

Ok, finished the first batch of fingers, and have filtered off and seperated the gold flakes from the green solution. The solution is bright green, like green kool-aid.

What could be in this solution, and how to I drop the metals out? Specifically, in your video showing the muriatic acid/peroxide method, you comment that the liquid was very yellow at first, leading you to think that there was gold dissolving directly into the solution.

You commented that you would drop it later with SMB.

What should I do to this green solution first? Try to drop out gold with SMB, or some other processing first?

-David

 

[lazersteve]

David,

If you want to reuse it, just leave it as is. Bubble some air thru it for 24 hours and use it again.

If you want to dispose of it, test it for gold with stannous chloride first. If it's positive drop the gold using SMB dissolved in water filer out the black powder (gold), clean it and drop the copper with iron. Neutralize the iron solution with lime and dispose of the rusty salt water safely.

If you followed my directions the gold most likely dropped out as the copper was dissolved. If you added extra peroxide or heated the reaction, you may have a little gold in the solution.

Steve