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

Subjecting electroless nickel solution to electricity

Hi. We are trying to recover nickel metal from used electroless nickel solutions by subjecting it to the idea of electrodeposition. I know that a reducing agent is present in the solution. Would there be any problem with this setup? Is the deposition of nickel faster since I have a reducing agent and at the same time electricity. I would appreciate any idea extended. ThankS!

JM Puguan
researcher - Cavite Philipines
2007

EN has a very low concentration of nickel to operate efficiently in a conventional electroplating cell. The process you want to do is not conventional electroplating, it's called electrowinning. It's based on the same principles, but in a broad sense, it differs from electroplating in that it operates under very low concentrations, whereas electroplating requires a minimum concentration.

Guillermo Marrufo
Monterrey, NL, Mexico
2007

---

First of two simultaneous responses --

I presume you want to recover nickel from spent electroless nickel baths. the easiest way is to add excess reducer and the bath becomes unstable and throws out virtually all the nickel as metal. However, you then have a problem with discharging the liquor. If you apply an electric current to the bath, you will get electrodeposition of nickel and it will be faster than for just electroless nickel. However, I am surprised that you haven't tried it - it will save you a lot of time if you just try it to see what happens!

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2007

---

Second of two simultaneous responses --

I have heard of spent EN being treated electrolytically by adding ammonia ⇦this on eBay or Amazon [affil links] to it.

It is also possible to treat it with "Venmet" solution (sodium borohydride in NaOH) such that the solids are a salable by product. It leaves about 30 ppm Ni in the liquid that needs to be treated further before release.

Dave Wichern
Consultant - The Bronx, New York
2007