antimon - 18-9-2015 at 14:38
Hi, i have collected e-waste for about a year or more, and recently i have started to prepare my waste bin material for extraction of the precious
metals thats in there.
I have been set on using a FeCl-HCl mixture to get the gold off the pins, and boards, but lately i have gotten interested in doing a electrolysis, but
i cant find much info on it.
Have somebody here done it?
Ps. I am building a fume hood this weekend, and i just wanted to ask if there is absolutely essential to have a plexiglass (Poly methyl metacrylate)
sash, or could i just buy another cheaper sort of plexi and save a few euros?
And how thick should i get? I am thinking of getting 0,5 mm.
Thanks guys.
MeshPL - 26-9-2015 at 10:33
Electrolysis doesn't sound like a good idea. Surely, I can imagine electrochemical dissolving gold in cyanide or halide solution (possibly acidified).
Also electrochemical dissolving base metals in solution of some oxyacid (likely sulphuric). But the problem is, such a dissolution may likely be
incomplete. So after long electrolysis you may find out, there are still pieces of whatever metal left on PCBs. Basically a piece of metal may remain
on board unaffected by electrolysis due to its connection to electrical current being etched out.
What I can imagine, however is complete dissolving metals by in situ electrochemically generated Cl2 or Br2 (but those will etch the gold). Maybe even
persulphate (which will not).
Br2 will be particularly good. Put boards on bottom of large beaker. Place carbon electrodes closely to the top. Fill with HBr or acidified bromide.
Turn on electrolysis. Produced Br2 will sink to the bottom and etch PCBs (after reaching certain concentration in solution).
However I don't think it is a patticularly good idea. You'd better stick with your HCl + Fe. You may also swap Fe for Cu.
Air is free oxidiser. HCl may not be, however
By the way you will use aqua regia to etch gold? Or will you just filter out undissolved "flakes" of it?
If I were you I wouldn't consider any plexiglass as material for any kind of fumehood part. Glass will be much better. BUT I'm not really experienced
so you'd better not rely on my words too much.
Still 0,5 mm is too thin. 3mm sounds good to me. But better go with glass. Unless somebody has actually built and used fu ehood made out of plaxi,
says it works ok.
Steam - 26-9-2015 at 10:46
My fumehood is made of plexiglass about 6 mm thick. It works like a charm, with a counterweight system I have on the back of it. I have never had a
problem with it.
antimon - 30-9-2015 at 03:42
I saw that there was a electrolysis method of loosening the gold from the pcb, but i havent found any instructions on how it works.
Later i am going to use aqua regia to dissolve it, and in the end get elemental gold through some processes.
Oh, i didnt mean that i was going to build it out of plexiglass, just the sash, like Steams.
Edit. I just saw that there were a method in the Technochemistry section a couple of threads down from mine. Im going to check it out.
Thank you for taking your time. 
[Edited on 30-9-2015 by antimon]
Little_Ghost_again - 6-10-2015 at 15:17
electrolysis for gold recovering is just. SO LAST YEAR. http://www.sciencemadness.org/talk/viewthread.php?tid=63606
Read and be enlightened to the new eco friendly easy way to riches and fortunes using common table condiments and a few other bits. Actually a lot of
great info in that thread and well worth a read for gold recovery