Recycling of electroless nickel plating baths

A. Hi, Dan. There are a number of strategies presently employed, from spontaneous plate out onto steel wool ⇦ on eBay or Amazon [affil link] , to evaporation, to electrolytic plate out cells. Some process vendors take back the spent baths as part of their service. You could research these options. What is the general approach you propose to offer please?

Hopefully you'll get some help and overall direction here, but you probably won't get highly detailed cost data. Nobody wants to deny anyone else a living, cousin, but when we ask people to donate their time & knowledge so we can better position ourselves to sell ours to them, they'll usually help a bit, but nobody goes gung-ho  🙂

Best of luck.

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

A. As far as I know there are no bath recycle methods in use on-site by platers because as hypophosphite is consumed it deteriorates to orthophosphites that are not easily removable, and they render the bath unusable after a number of turns ⇦ huh? . If your process removes orthophophites in a practical manner, it sounds like it has a lot of potential. Good luck!

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

A. Years ago, one of the major Mfgr's had purification equipment that would allow 20 to 30 tank turnovers/turns ⇦ huh? . It was expensive, so it was only of value to shops that did a lot of EN work every day. For the small shop, taking good care of the bath to hold down the reducer break down product and getting 6 to 10 tank turnovers is more cost effective.
There is a company in Texas that will take the spent solution for a lot less than the treatment and burial costs and it is free from compliance with EPA because the nickel is recycled. It still ships as a hazardous material, but not as a "waste".

"Electroless Nickel Plating: Fundamentals to Applications"
by Fabienne Delaunois et al

on Amazon or eBay
or AbeBooks
(affil link)

A. Dan, it's usually called extending EN bath life or rejuvenating EN baths.

See 'Extending Electroless Nickel Bath Life Using Electrodialysis' among EPA Metal Finishing Pollution Prevention publications:
http://www.epa.gov/region9/waste/p2/projects/metal.html ⇩
Also available at https://www.nmfrc.org/merit.cfm ⇩

"During EN plating, by-products of the chemical reaction, including orthophosphite, sodium sulphate, and ammonia, build up and decrease bath performance. Orthophosphite, which is produced when hypophosphite is oxidized during the plating reaction, is the most significant by-product.."

I believe James Watts is referring to orthophosphite precipitation via USP-grade calcium or magnesium hydroxide addition, while at a low enough pH to avoid nickel precipitation. The precipitate is then removed by filter pressing, and the Ni-containing liquid recycled. Filter cake is water rinsed several times in press to remove residual Ni, making the solid waste non-hazardous. It is necessary to use a modified EN solution to minimize the buildup of other byproducts.

See also
'Extending the operating life of electroless nickel by chemical means,' by Helmut Horsthemke and Stanley Zabrocky, Metal Finishing, October 2004, Pages 38-41.

'INVESTIGATION INTO THE REJUVENATION OF SPENT ELECTROLESS NICKEL BATHS BY ELECTRODIALYSIS,' by P. T. Bolger and D. C. Szlag, ENVIRONMENTAL SCIENCE & TECHNOLOGY, vol. 36 (no. 10), pp.2273-2278 (2002).

And the patent literature.

Ed. update: The above links are broken. Thankfully, the Internet Archive preserved copies here and here  🙂
Please consider a donation to The Internet Archive. Don't follow abandoned links, old URLs are sought out by hackers!

A. I believe both Shipley (old Lea Ronal) and Macdermid were marketing equipment to rejuvenate EN solutions in plant to reach a so called no dump stage. I also seem to remember that they were willing to reprocess at their facility for smaller users. I do not know if this is still offered. Other manufacturers took back EN for "reprocessing" but I believe all they did was recover the nickel content. Considering the present price of Ni metal and Nickel chemicals a method to recover any of the cost might be timely

? Hi, David. Could you clarify whether you are looking for additional comments about the technology, or you are seeking a disposal contractor, please? Thanks.

Regards,

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

A. The plating out with steel wool is typically not performed for nickel recovery, it is performed for the waste treatment. The nickel will plate out on the wool and leave a solution that does not require any further treatment. It is not worthwhile to recover the nickel from the steel wool.