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-----Remove sodium metabisulfite from Nickel Plating bath
Q. Sodium metabisulphite was added by mistake to Nickel plating path. How can I get rid of it?
asghar norouzi- tehran, Iran
December 2, 2021
A. You don't say how much SMBS you added but you can render it innocuous by oxidizing it with Hydrogen Peroxide.
Geoffrey Whitelaw
- Port Melbourne, Australia
January 18, 2022
A. First question is why was sodium metabisulphite added to a nickel bath? It is used as a passivating agent on nickel and in the separation of an electroform from a reusable mandrel. Assuming the nickel bath is used for electroforming, removal of the metabisulphite by adding hydrogen peroxide, as suggested by Geoffrey. This will convert it to sulphate, but then bath may become out of balance and if it is being used for electroforming, this could create issues with brightness and throwing power. It could also have secondary effects of hardness and stress if the extra sulphate throws the bath out of balance. Excess sulphate can be removed by the addition of barium salts and the precipitation of barium sulphate. Either way, I recommend re-analysing theh bath before any further work is sent through it.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
January 14, 2022
My guess is that someone mistook a bag of sodium bisulfite for a bag of boric acid due to language difficulties :-)
I'd probably mistake a bag of "$%^#B00!@$" for a bag of "@$!%^$#B00+#!" myself :-)
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
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