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How to waste treat nickel boron

Nickel Boron contain: Nickel Chloride 6H2O, Sodium Borohydride, Ethylenediamine, Sodium Hydroxide

Stephanie D
metal finishing - Santa Ana, California, USA
2006

Tough problem! Sounds like what you have is a borohydride reduced electroless plating solution.

I would try adding a large excess of borohydride, and deliberately causing the bath to "crash" - deposit as much metallic nickel and nickel boride as possible. This will leave you with a solid sludge that is about half nickel metal by weight (You should be able to sell this) and a liquid phase that retains 25 - 100 ppm Ni. This then needs a secondary treatment. I have seen this done with sulfide based treatment chemistries, after lowering the pH into the 8 - 8.5 range. Care must be taken to avoid generating hydrogen sulfide in this step.

Ethylene diamine is a very powerful chelating agent. It may not be possible to get the nickel below 5 - 10 ppm. You may find that the more economical solution is to ship the waste off, as is, to a recycler. The nickel values are such that you might get money for it.

Good luck!

Dave Wichern
Consultant - The Bronx, New York
2006

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