plating, anodizing, & finishing Q&As since 1989
How can I reduce the amount of Iron in my Cadmium tanks?
I am new to the plating industry and have these old cadmium plating tanks. The solution is composed of cadmium, cyanide, sodium hydroxide, and sodium carbonate / washing soda [affil link]. There is also a little bit of iron and I was looking for a way to remove it from the solution, does anyone know of any good processes? Thanks.Michael Nishimura
engineer - Garden Grove, California, USA
First of two simultaneous responses --
You don't say how much iron is in the solution. It is generally pretty rare to find a cyanide cadmium solution which has enough iron to effect plating.Gene Packman
process supplier - Great Neck, New York
Second of two simultaneous responses -- 2005
When using a Cyanide Cadmium process that has iron in it, you will form a very stable complex between the Cyanide and the iron. It is called "Ferrocyanide." This complex is extremely stable, and difficult to decompose. For that reason, the only practical way to lower iron in a working bath, is to cut or dilute the solution. Personally, I am never in favor of cutting or diluting a solution, unless it is the only way to get out of difficulty.
Since the iron is firmly tied up with the cyanide, I doubt that you should see much in the way of problems with the deposition of your Cadmium.
Ed Budman [dec]
With deep sadness we advise that our good friend Ed passed away Nov. 24, 2018
Thank you for your responses I appreciate the time you spent. We are trying to adhere to specification MIL-STD-870B that has a total iron concentration limit of 300 parts/million and we are getting about 800 right now.Michael Nishimura
- Garden Grove, California, USA
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