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Remove chlorides from a high speed chrome plating bath

Looking for the best way to remove chloride contamination from my chrome tanks. I'v been in touch with our chemical supply company and also talked to a competitor about a good solution to this problem, what I heard from both of these sources was in complete contradiction to each others methods. Please advise.

Thank you, Jeff Hanaway

Jeff Hanaway

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The best method that I have found is to do a draw off the bath.

Some people add silver oxide, but this should be done in a separate tank to ensure that the precipitated silver chloride is completely filtered out during the transfer back to the plating tank.

I have heard of people dummy plating the chloride out of the tank, but in an aqueous environment the chloride reacts with the water to for hypochlorous acid. I have not tried dummy plating to remove chloride, though.

One could probably remove the chloride with ion exchange resins, but that would probably remove the catalyst also.

John L. Zable

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Dummy is a good solution to chloride contamination. I do not remember the exact conditions, but I think it is done with a small cathode and high current density. I know it works. For more accurate conditions, leave a massage for Jim Watts, or send him an e-mail, he knows the answer for sure.

There is another possibility,to add barium carbonate. The chloride acts as a catalyst just like sulfate ( actually a stronger one then sulfate) so by reducing the sulfate, you actually reduce the effect of the chloride. The chloride will decrease with time and then you will have to increase the sulfate again. It works!

Sara Michaeli     chemical process supplier Israel

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To remove chloride from a chromium plating solution, you can add silver oxide or silver carbonate. Both methods are expensive due to the cost of silver salts. Use stoichiometric amounts

Electrolytic dummying of the solution is very effective, especially if the contamination is high. There are a variety of recommended electrolytic procedures and one that I am familiar with (and it works) is to Electrolyze the solution using an anode to cathode ratio of 10:1 while maintaining an anode current density of 25 ASF.

Trust this helps.

Ken Lemke Burlington, Ontario

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September 20, 2011 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

how to remove chloride content from hardchrome plating solution??

Chandan Parmar
service engineer - Ahmedabad, Gujarat, India