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Rate of Sodium Carbonate Build-up in Stored Cyanide Plating Baths

Would anyone know if sodium carbonate will continue to build up in a cyanide plating bath (Cd and Cu) if we store it in a tightly sealed container at room temperature? If yes, how fast and will dangerous gases accumulate in the drum? (The stored solution would serve as backup so it's not being used until we have to remove carbonates in the working bath.)

Romina Garcia
Engineer - Winnipeg, Manitoba, Canada
February 10, 2010

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First of three simultaneous responses --

Romina,
During electrolysis carbonates will rise naturally, and breakdown products build up slowly while plating from the cyanide process. The carbonate level in the baths will not rise when the baths are stored the way you describe. Good Luck!

Mark Baker
Fellow Plater - Syracuse, NY USA
February 12, 2010

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Second of three simultaneous responses --

In a tightly sealed container there will be no carbonate formed.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
February 12, 2010

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Third of three simultaneous responses --

I don't advise this if you are going to be storing the solution for very long. Cyanide solutions hydrolyze (react with water) to eventually form formate and ammonia. The reaction follows 1st order rate kinetics and is dependent only temperature and time. The lack of exposure to air will have nothing to do with this reaction. If a sealed drum is in hot summer weather, you may eventually have problems with pressure buildup from within the drum do to the ammonia ⇦this on eBay or Amazon [affil links] formation. All of that being said, it is probably fine for short periods, but I can't really say how long of a storage period is acceptable.

Jon Barrows, MSF, EHSSC
GOAD Company

Independence, Missouri

February 12, 2010

Thanks very much for the feedback. I find this site very helpful.

Romina Garcia
- Winnipeg, Manitoba, Canada
February 17, 2010