44020

Activated Carbon used in Nickel Plating  

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Dear Experts:

If I place activated carbon bags in a filter, how do I know when to replace it ???

Is there some visual cues to tell us when ?

Is there any literature that establishes it for this process (bath turnovers, flowrate, amount of activated carbon, work load ...)

Lan Ha
aerospace - Tempe, AZ, USA

Powdered carbon absorbs more quickly than granular but likewise it doesn't "last" as long.

The rule of thumb we use here is about 2lbs per 40 hours of contact time with the bath. You need to watch your surface tension though as wetting agents can saturate the carbon rather quickly.

I'd recommend running the bath through a carbon packed filter instead of hanging bags of carbon over the side. The filter method is more effective for general plating practices.

Jim Ott
plating shop - Middletown, PA

Hello Lan,
There is no way to tell visibly if the activated carbon is spent and needs to be changed. The general rule of thumb for nickel plating solutions is 2-4 lbs activated carbon per 100 gallons of solution. The amount of time would depend on the degree of organic contamination present. Good Luck!

Mark Baker
Process Engineer - Syracuse, New York

Dear Jim:

1. Your information seems to be helpful! Can you let me know the size of your bath ? Like how many gallons ???

2. We don't used wetting agent in our bath. It's conventional Watts Bath.

3. We fill our own bag with activated carbon granular and place it into penguine filters. So, it's rather packed!

Dear Mark:

Your suggetion is 2-4 lbs of activated carbon per 100 gallons of solution. I understand it will remove the organic contamination. But how do I know when to dispose and replace ???

Thank you both for sharing your thoughts.

Lan Ha
Acme Aerospace - Tempe

Lan,
If the filter chamber is packed too tightly with activated carbon you will restrict the exposure of solution to carbon. If the chamber is too small, you may want to look into getting a larger vessel like a carbulator (sp)?? Two to four pounds activated carbon per 100 gallons should be good for 24 hours with no problem. Don't re-use the carbon after the treatment. You should not have to repeat the process after 24 hours. Good Luck!

Mark Baker
Process Engineer - Syracuse, New York