Is nickel and chrome recovery practical for small ABS plating plant?

A. For the drag-outs for your acid copper and nickel, continuously recirculate through an electrolytic recovery cell. For your chrome drag-out, periodically remove a portion, evaporate it to an appropriate volume, and run a "porous pot purifier" in it until tramp metals are removed, and trivalent chrome reoxidized. Then, add it back to your bath.

A. I agree with D. Wichern's advice on the acid copper and chromic acid etch and plating bath, but have a different suggestion for the nickel dragout(s). Nickel is difficult to recover electrolytically compared to copper.

There is enough evaporation from the nickel plating bath to allow return of the dragout to the plating bath. While this will accelerate the build-up of contaminants, the savings are worth it. At least 75% of the nickel dragged out can be recovered.

For the nickel and chromium plating dragouts, RO or DI water should be used for make-up to avoid contaminants from tap water.

Lyle Kirman is quite right. I didn't think of that.

Some years ago, I had a customer who added back evaporated decorative Ni static rinse to his bath. He called me in because he was starting to get persistent ugly haze in the low/mid range. His basic chemistry was fine.

I had really good luck, in a Hull cell, anyway, getting rid of it by treating with a weakly basic IX resin. My interpretation is that it removed organic contaminants, anionic in nature, that result from the anodic oxidation of brightener compounds. Sadly I never got to try this out. He was one of those fellas who thought I had a magic potion to add that I was withholding until I got enough money out of him.

What do you think, Mr. Kirman? You're the resin expert.

You are probably correct that the IX removed some brightener breakdown products. Another possible cause of the haziness might be a build-up of calcium.