Martin wrote:
Over the years I've accumulated a bunch of electronic surplus, much of
it gold-plated (edge connectors, PC boards, etc).

I was wondering whether anyone has a simple process for using this
scrap as the sacrifical electrode to perhaps "plate" all the gold onto
another object, from which it may be easily scraped off and
recovered? My only experience with similar processes is electrolytic
de-rusting.

Is it possible to plate the gold without also transporting the base
metal to the plated electrode?
Kind of. There's a guy who has come up with a new process. It
doesn't actually plate the gold onto anything, but it does
remove the gold and it precipitates out. It doesn't work on
non-conductive substrates like PC board edge fingers, though.

You could actually de-plate the gold onto something like
graphite, but it is very slow and you still get base metals.

See http://www.goldrefiningforum.com/for a new forum discussing
this. They've just moved the forum to new servers, and so I'm
not sure where everything is now. You have to "join", but it
will be WELL worth your while to do it. This is one of the best
resources I've ever seen on the net!

I have been salvaging gold from connector edge fingers with a
highly toxic solution sold for this purpose (cyanide). The
company that makes it wants to do the recovery from solution for
you, but you'd need a hazmat license to ship the stuff back to
them, so I couldn't if I wanted to! I have been fooling around
with this and have recovered about 3/4 Troy Oz of gold so far.
I have no idea how much I may be losing in the process.

The process the above web forum describes looks very good, it is
all done with drain cleaners and such from the hardware store,
and the amount of gold these guys are getting out just about has
me drooling! Just so you know which one I am talking about, I
think it is "LazerSteve" has a process where he uses sulfuric
drain cleaner plus glycerine to deplate the gold. Another guy
figured out you could put a layer of the pins on a stainless
steel screen and the pins would deplate just the same, with much
less handling. He uses a lead anode on the bottom of the jar.
When the solution is full of the "black" colloidal gold, he then
dilutes the solution and filters out the gold with coffee
filters. He then purifies the result with another process to
remove the small amount of base metal.

Jon