The authoritative public forum
  for Metal Finishing since 1989
  

  -----

NON-CYANIDE STRIPPER FOR IMMERSION GOLD PLATE

MY CLIENT IS TRYING TO FIND A NON-CYANIDE METHOD OF STRIPPING IMMERSION GOLD FROM NICKEL AND FERROUS ALLOYS. WE ARE CURRENTLY USING REVERSE CURRENT IN A SODIUM CYANIDE, SODIUM HYDROXIDE BATH. IT WORKS WELL BUT WE ARE TRYING TO GET AWAY FROM THE WASTE TREATMENT PROBLEMS WITH CYANIDE. THE IMMERSION DEPOSIT RESULTS DURING GOLD ELECTROPLATING PLATING OF THE PINS ON CONNECTORS. YES, WE GO IN HOT BUT WE STILL GET IMMERSION DEPOSITS ON AREAS WHICH ARE NOT ELECTRICALLY CONNECTED.

Bert J. Sherwood
- Los Angeles, California, USA
2001

---

As you are already using cyanide I can suggest an operation that will work at lower concentration and therefore easy to treat. Try 5 g/l sodium cyanide with air agitation from fish tank bubbler and a drop or so of hydrogen peroxide.

Geoffrey Whitelaw
- Port Melbourne, Australia
2001

---

Hello,

I'm looking also for a non-cyanide stripper. We currently run a Nickel and Gold operation in China. The 5g/l sounds good, but what's this about a little bit of hydrogen peroxide? Isn't that highly corrosive with a very low pH. Then not specifying how much to add seems a little dangerous to me. There's a lot of free cyanide in a bath like this. How Much hydrogen peroxide is required?

Thanks,

Leonard Jackson
- Fuzhou, China
2004