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

Disposal of Electroless Nickel

2000

I am trying to dispose of Electroless Nickel in the environmentally friendliest manner possible. Plating out the metal does not seem to work. Has anybody done it? What did you have to add to break the complexes? Has anybody got a better idea as to how to dispose of it.

Thanks for your help!

Best Regards

Trudy

Trudy Hattingh
Chemserve Trio - Durban, South Africa

---

Here in the U.S. this is not a big problem anymore because many of the vendors take the solutions back for disposal or recycling when exhausted. But to plate out the nickel, what you need is 00 steel wool ⇦this on eBay or Amazon [affil links] because of its very large surface area.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2000

---

First of two simultaneous responses-- 2000

Assuming that it is a normal EN, elevate the temp to the top limit, put in some steel wool and raise the pH with NH4OH to about 0.5 pH higher than the recommended top limit. The bath will literally self destruct. It will plate like mad on the tank also, so have an old junker tank to do it in.

I never did it, but I would guess that a SS cathode, bagged carbon anode, top of the recommended temp and pH, great agitation and about 6 volts should give a very rapid plate on the cathode. If it was passivated, you should be able to peel the nickel plate off.

James Watts
- Navarre, Florida

---

Second of two simultaneous responses--

As Ted said, 00 steel wool ⇦this on eBay or Amazon [affil links] is a good process to decompose an EN bath ,just be very careful as you will get a lot of hydrogen and it might explode. Make sure that you are able to control the EN decomposition.

Sara Michaeli
Tel-Aviv-Yafo, Israel
2000

Plating out spent Electroless Ni on steel wool ⇦this on eBay or Amazon [affil links] will only work while there is an excess of reducing agent, so you may need to add additional hypophosphite to get a low residual nickel concentration.

Sodium borohydride has also been used for this purpose, but still results in 10-30 mg/l of soluble and difficult to treat Nickel.

Electrowinning is difficult unless you have an extremely high surface area cell, heat and pH control.

A lot of people use the steel wool method and treat the residual with carbamates.

Good Luck!

Lyle Kirman
consultant - Cleveland Heights, Ohio
2000

Can the process of plating out the nickel from an EN bath using SS anodes, etc. (as described by James Watts) be also used to plate out nickel from a Bright Watts formula? How clean would the resulting liquid be, and what else would be required to render the solution harmless?

Ian Wallace
- LA, California
2000

---

I need a little help. Having exhausted chemical precipitation of electroless nickel, I'm conducting a little R&D on plating out the nickel.

I took a 1,000 milliliter beaker [beakers on eBay or Amazon [affil links] of electroless nickel and dropped in some steel wool [affil link on Amazon]. I raised the pH to 9.0 with a strong spent ammonia ⇦this on eBay or Amazon [affil links] solution. I did not seen an any visible plating out of nickel. I then added some sodium hypophosphite solution in varying concentrations to assist in the reduction of the nickel. I am not noticing any plating out of the nickel. Any further guidance your readers can offer would be appreciated.

Jim Sullivan
- Paterson, New Jersey
2005

I use the steel wool process and add some extra hypophosphite, then plate out at operating temp. It usually plates out down to 15-30 ppm Ni. Then I remove to batch tank, raise pH to 9.0 ( min.) I then add 800 ml of 30% hydrogen peroxide to oxidize excess hypo, mix for 2 hrs. add DTC to precipitate the rest. I get .5-1.0ppm Ni. With out the peroxide I could only get 5-10ppm Ni. It would also affect the conversion of Cr+6 in my flowthrough system when running the clean water off of the top of the batch thru the system for discharge. I have 200 gal EN tanks I have had good success with this process , you will have to play around with the amount of peroxide to use so you don't get floating of your sludge when discharging to your system. let me know how this works for you...EK

Eric King
metal finishing - Tualatin, Oregon, USA
2006

Forgot to add that I use caustic soda beads [caustic soda beads in bulk on Amazon [affil links] to raise ph NOT ammonium hydroxide...MAKES BIG DIFFERENCE EK

Eric King
metal finishing - Tualatin, Oregon, USA
2006