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My rhodium bath has too much zinc and copper

My rhodium bath has got too much zinc and copper so my bath is plating dark. I want to take the zinc and copper out of my bath.. what must I do?

Begüm Bilgin
jewelry - Istanbul, TURKEY
2007

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2007

Hi Begum,
can you tell us how did you arrive at the conclusion that your Rh bath is contaminated with Zinc and copper!
Rh. bath can give blackish deposit on many reasons.
Please be specific. You will get very good response and support.
Please let me know the following:
1.Volume of bath.
2.How old is your bath (age)
3.Conc. of Rh/ltr
4. Metallurgy of items you plate(is the base metal have Zn/Cu)
5.frequency of usage
6.Temp. of bath
7.current passed-voltage and amp
8.Qty plated per shift/day/week/month!
9.what is the pretreatment steps.
10. quality of water used.
11.quality os acid used in the plating bath
The list is endless.
regards,

T.K. Mohan
plating process supplier - Mumbai, India

TK has many excellent points. If you know for a fact that the bath is contaminated with Zn and Cu, your Rh supplier should have the process of precipitating unwanted metals from the bath, then filtering off. I used to do this purification process for my customers all the time. Although a simple process, I am reluctant to give you the process on-line because I don't want to be liable for any misunderstanding or lack of communication if something goes wrong with the process. After all Rh is very expensive. Contact your supplier, if they value your business they will help you. Good Luck!

Mark Baker
Process Engineer - Syracuse, New York
2007