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Reduction of Hexavalent Chromium to Trivalent by bubbling air

I have seen a business bubbling air into their final rinse tank in their chromate conversion coating process (immersion in tanks). They tell me this will convert the hexavalent chromium to trivalent chromium. This allow cheaper disposal to sewer.

Does anyone know if this will work?

Evan Miller
plating shop employee - Springwood, QLD, Australia
May 19, 2010

Hi, Evan. The air bubbler is for agitation, not for reduction of hexavalent to trivalent chromium. It won't work. If it did work, there would be no hex chrome in their chromate conversion coating tank 🙂

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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May 19, 2010

I would expect air to oxidize the trivalent to hex.

James Watts
- Navarre, Florida
May 19, 2010

Sorry! Finishing.com is temporarily Read-Only.
Ted Mooney is retiring but I have several offers to take it over.
We're working hard to make sure we find it the best new home.

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