The authoritative public forum
  for Metal Finishing since 1989
-----

Plating out multiple metals using sulfuric acid

 

Hello all.

I'm setting up an etching tank using a straight sulfuric acid solution.(93%) I need to confirm some theories that I have about the use of this acid. All substances put into the solution are ground pc boards, coins, hard drives, monitors, and anything else that is metallic or electronic, ground up together to the size of sand.

1. When copper, aluminum, zinc, siver, or iron is dumped into the acid The resulting solution will now be a sulfite of those metals?
2. If I introduce the proper anodes an cathodes, the metals should start to plate onto their respective cathodes?
3. By constantly pouring more metals into the solution, theoretically the plating process would continue indefinately?
4. Will the exhaust have any harmful fumes such as sulfur dioxide?
5. Can those harmful gasses be filterd out? Please be as forthcoming as possible, as I have no ego to bruise. Thanks in advance.

John P. Lombardo
- New Hyde Park, New York, USA

---

 

1. When copper, aluminum, zinc, siver, or iron is dumped into the acid The resulting solution will now be a sulfite of those metals? No, some of the metals will dissolve, releasing explosive hydrogen gas.

2. If I introduce the proper anodes an cathodes, the metals should start to plate onto their respective cathodes? No, the metals will not plate onto their respective cathodes, some will plate out, some won't, they won't look like the metal you are expecting, they will plate out as a black, nonadherent mass, if at all.

3. By constantly pouring more metals into the solution, theoretically the plating process would continue indefinately? No, some will build up to their solubility limit, most will just sit at the bottom of the tank, eventually filling it.

4. Will the exhaust have any harmful fumes such as sulfur dioxide? Ohhh, yeah.

5. Can those harmful gasses be filterd out? Not without a carefully engineered exhaust and scrubber system which is expensive, even for commercial operations.

Please be as forthcoming as possible, as I have no ego to bruise. Thanks in advance.
Please go back and study the chemistry before attempting anything like this again, for your own safety, and for the safety of life and limb in your neighborhood.

  
Tom Pullizzi
Falls Township, Pennsylvania