Recycling of electroless nickel plating baths

Hi, Dan. There are a number of strategies presently employed, from spontaneous plate out onto steel wool ⇦this on eBay or Amazon [affil links] , 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?

Hopefully you'll get some generalized help and overall direction here, but you probably won't get the detailed cost data or in-depth feedback you'd ideally like. Nobody wants to deny you a living, cousin, but asking people to donate their time and knowledge to you so you can sell yours back to them usually doesn't work too well :-)

Best of luck.

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

Years ago, one of the major Mfgr's had purification equipment that would allow 20 to 30 tank turnovers. 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".

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.

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,