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Ion exhchange for trivalent chrome

We are in the process of replacing our hexavalent chrome tank with a trivalent chrome tank.
Our supplier is recommending a premier resin for our ion exchange system while another supplier was suggesting what they call a standard resin. The premier resin cost's roughly twice as much as the standard resin but our supplier says that it will last longer between regenerations and we will not have to regenerate with caustic every time like we would with the standard. They also tell us that it will remove the impurities better and will pay for itself quickly. Does anyone have any experience with the two types of resin to confirm what my supplier is telling me?

Tom Fardink
- Jamestown, New York
2006

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I'm not sure what you are doing. Treating rinsewater? from plating or chem film?

Suggestions: Check the IX resin mfr. websites & get the product bulletins, then get resin bead samples & do feasibility tests using 100 ml burets (bit of glass wool above the stopcock) as IX columns. Also, ask the supplier to warranty the claimed performance.

Question: Isn't hexavalent chromium present as CrO4(-2) anion, while trivalent is Cr(+3) cation? Cation resins are regenerated with acid.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2006

I misspoke about the regenerant Acid is used to regenerate the resin but ammonia ⇦ this on eBay or Amazon [affil links] can be used to help remove organics instead of using alcohol and it is also used to aid in the removal of copper. The ion exchange unit for a trivalent chrome system uses a special resin that removes impurities from the plating solution, mainly copper, nickel, and zinc. It has nothing to do with waste treatment it was put into the wrong category.

Tom Fardink
- Jamestown, New York
2006