Carbon Treatment of Nickel Plating Bath

A. The most important tool for this is a Hull cell.

A. Check the carrier breakdown products by HPLC.

A. Your continuous filtration should be with carbon. Complete carbon treatment is usually performed once in 6 months.If you need it more often it means that you are doing something wrong. The brightener process you use is manufactured by a known supplier and the fact that you cannot find the right balance balance between the primary and secondary brightener means that you are not operating the solution in the right way.

Ask your supplier for the right maintenance instructions. You could also ask for a system that is based on one component maintenance additive, may be this will make it easier for you . As for Jeff's recommendation to check the brightener by HPLC, well most platers don't have access to this equipment. Your supplier probably owns an HPLC but usually it is not required to maintain Nickel solutions with it.

A. Dear Frank,

I wonder if looking at carbon treatment frequency alone would help solve all your difficulties seeing that you are using the bath for plating on brass. I would go with Sara Micheali to advising continuous filtration using carbon which should suffice for organic impurities, but 24 hour in tank filtration can actually assist dissolution of fallen brass parts in your tank.

It makes better sense to have a once in 24 hour transfer filtration to retrieve fallen parts. Also increase use of the wetter or additive atleast 2 or 3:1 to the brightening agent whilst plating brass.

Also introduce a chelating agent dose with the brightener system as SOP for trouble free work. You will find these three extra measures will reduce the frequency of batch treatments. regards.

A. You're lucky no one died, John. If your system controls and work rules are such that cyanide can accidentally get mixed into a nickel plating solution, you have a much more compelling problem than studying how to troubleshoot. But I'm not clear what you mean by "treat" -- Do you mean "treat before disposal" or "restore and make functional"?

I don't think there is any way to remove nickel cyanide from a plating bath and make it functional again, but oil can be removed by high temperature carbon treatment in a separate tank. Please give us some more detail.

A. Hey John,

I know with nickel prices the way they are, saving the bath looks pretty attractive. I'm thinking you are going to be having many, many headaches trying. Nickel cyanide is one tight little complex. Hard to break that bond in ideal situations. It might be worthwhile to try a pretty harsh peroxide/carbon treatment and a high amp dummy load, but with the low ph in the bath I don't think it is going to do much to the cyanide and you can kiss most of your brightener package goodbye. Might be better to start over fresh with a new bath and some serious employee training.

Ted is right. That could have been a deadly experience.
Good Luck.

Dear Trent,

Thanks for the suggestion. I'll try to do what you have suggested and if it still doesn't work. Might as well dump the whole thing.

Thanks!

A. John,

Single salt of cyanide (Nickel Cyanide) are NOT soluble in water. It could be at the bottom of the tank or in the filters.
Filter/Test a small amount(267 ml) of your solution in a Hull Cell at 1.0 amp, 5-minutes with agitation at your operating temperature.
Peroxide/carbon treat/filter same solution and re-run in the Hull Cell at the same parameters above. See if there is an improvement in the plate or you may add and balance your brightener and make sure you adjust your plating parameters according to the suppliers recommendations.

This is not easy, you may run your test and treatment several times until you find the right amount of peroxide and carbon, and additions to your plate solution.

Make sure you run your test in a well ventilated Hood.

Lots of luck.

Thanks for the authoritative replay, Hamilton!

Regards,

A. I agree with Ted. You carbon treat when the Hull cell determines that you need a carbon treatment. It has nothing to do with time unless you're operating under perfect conditions, which is unlikely. Analyze the solution, adjust it to optimum, run a panel, carbon treat the sample, and run another panel, with the necessary brightener additions, of course. If the panel is improved to your liking, carbon treat.

Carbon filters don't do a tenth the job that a high-pH H2O2 carbon treatment does.

A. Hi,

The nickel solution should always be treated with carbon filter paper or carbon. Change the filter paper once a week.
It's no problem to hold the brightener in condition in the nickel solution.

Regards