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  for Metal Finishing since 1989
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Removing Aluminum from etching bath

Presently using feed and bleed to maintain aluminum levels in an etching process.
I would like to know if a seperation process has been developed to remove the complexed aluminum hydroxide from an etching bath and returning the water to the bath so as to minimize wastewater volume.

Gary Levesque
Research + Development - Hyannis, Massachusetts
2005

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I know of "filters" that can accomplish this, I believe that Eco-Tec makes such a beast... From what I understand they operate on a somewhat similar technology to sulfuric acid purifiers in that the caustic (I'm assuming your talking about a Sodium Hydroxide etch by the way) is absorbed by some medium while the aluminum isn't. I never really bothered to learn too much about them though after finding out that we'd have to use something to the tune of 15 times as much etch as we currently do before it would have become economical to buy one.

So, does the technology exist? Yes. But, it might not be the solution you're looking for.

Good luck.

Jim Gorsich
Compton, California, USA
2005

Thank you for your reply. I did a little research myself and found that membrane technology may be a solution to this problem. It has yet to be determined if the electricity and membrane maintenance is economically viable.

Gary Levesque
- Hyannis, Massachusetts
2005