The authoritative public forum
  for Metal Finishing since 1989
-----

REFINING USED GOLD PLATING SOLUTION?

February 24, 2009

Hi, I run a small Precious Metals Business.
I have about 300 liters of used gold plating solution that I think has gold still in it. What's the best way to refine it ? So far I have just been plating it out with my rectifier, using S.steel anode and cathode, then scraping off the gold and melting it in my furnace.. But I am looking for a better way to do it..
Thanks Wyatt

Wyatt Walker
gold supplier - Australia

---

February 26, 2009

You might try plating out onto a mild steel cathode. Then, instead of scraping the gold off, you could briefly immerse it in a muriatic acid ⇦this on eBay or Amazon [affil links] bath. Then, the gold will just fall off and you can recover it from the bottom of the tank.

Dave Wichern
Consultant - The Bronx, New York

---

February 27, 2009

See my response to letter 51365
You will save yourself a lot of work and worry.

Geoff Smith
Hampshire, England

---

March 3, 2009

Thanks for the suggestions Dave and Geoff.
Geoff I am actually a refining company, and am doing the job for a customer. I have been doing it for years, but working with old plating solution is only a small part of my business. I was just looking for a easier way to do the job.
Thanks for the suggestion Dave, I am going to try using mild steel and then dipping them into muriatic acid. What strength muriatic should I use.
Thanks Wyatt

Wyatt Walker
gold supplier - Australia

---

March 6, 2009

When I did this type of Au recovery, I used 1:1 HCl/water. Still pretty "hot", but diluted so as not to be too fume-y.

The acid goes into pores in the loosely adherent gold deposit and dissolves a bit of iron beneath...and the gold falls off. They get consumed after a while, so don't use anything too fancy or hard to fabricate.

Dave Wichern
Consultant - The Bronx, New York