Nickel recovery by electroplating

A. 15 volts is mega too high for nickel plating. Drop the voltage to 4 V for a start and use a lot longer time. High amperage nickel plating requires extreme agitation.
You might try putting your anode a little bit closer to the part (cathode). For beaker plating, you could go to 1 inch apart for many things.
Set your beaker in a large glass dish that is about as deep as the liquid level of the beaker and add an inch of crushed ice to the dish. Add more as the temperature rises.
You can agitate your solution with air from a fish tank air pump.You will need a control valve in the line. Do not use a fish tank air rock as the solution will dissolve it. You can put holes in the plastic tubing on the bottom of the tank with a drill or a red hot paper clip. Weigh the tube down with a glass rod or stainless steel wire.

A. Everyone wants to plate faster, Haf, but they'd also like cars that go 200 MPH, get 100 MPG, and carry a family of 7 in comfort. A starting point is to compare your current density with published values. You probably will not successfully plate at much over 40 amps/ft2. Where are you now?

The closer the anode to cathode spacing, the lower the voltage; and the lower the voltage, the lower the temperature rise. But you certainly need nickel anodes, cost effective or not. It is hard for us to guess what we need to tell you about if we don't know what you know and what you don't. That's an advantage of books: there's enough room to cover everything. Do you have access to a few books on nickel plating? Good luck.

A. Sorry, but after 3 postings and 3 responses I still don't quite understand what you are trying to do or why, Haf. But the closer the anodes to the cathodes, the lower the solution resistance, so the lower the voltage you can use, so the less power you waste to the solution and lower the heating effect.

As for other websites to visit, please google for Ohm's Law. After you feel comfortable with that, google for Faraday's Law. Those will arm you with the basic understandings you will need to understand the relationships between voltage, current, spacing, plating time, thickness of deposit, etc. For books, any of the "must have" texts on our Books page will be tremendously helpful.

You will find it impossible to plate nickel to low levels this way though. The "efficiency" will drop faster than the nickel concentration. That is, as the nickel level drops, more and more of the applied electricity will just release hydrogen and oxygen instead of depositing nickel. To recover nickel from waste, you generally need super large surface area cathodes (reticulated copper or carbon) and extreme agitation. Good luck.

A. Hello again, Haf.

You will need a platinized titanium anode if you will not be using nickel anodes. There is certainly a relationship between solution agitation, interelectrode distance, solution concentration, and maximum successful current density -- but it isn't a simple formula. Each of those variables interacts with the others.

Your close interelectrode spacing helps keep solution resistance down, which directly keeps plating voltage down, which directly keeps power consumption down -- and power consumption is the same thing as heat. So you do not want to increase the distance, you want to increase the solution agitation!

In your first posting you said your object was to make a nickel nugget as an experiment. When we advised what parameters to use, you said plating that way would be too slow and nickel anodes are too expensive, which didn't seem to make sense if you were trying to make a nugget. But when we tried to clarify the issues in that new light, you then said the answer was no good because your object was actually to remove the nickel from the solution. Then we said that will not work properly with this setup because the efficiency will plummet as the concentration goes down. Now you are saying the efficiency is too low.

Can you please help by forthrightly describe exactly what your goal is -- what exactly you are trying to do and why? In other words, are you a student trying to make one nugget, or are you an engineer trying to build an electrowinning plant for the production of nickel, or are you trying to develop a process to remove nickel from waste streams as a pollution control measure, or what? As you can see, we can't efficiently help you get where you trying to go if you don't tell us where you're trying to go :-)

Thanks!

A. Hi, Paulo. No, I don't think you can recover pure nickel that simply. But you may be able to precipitate the iron with peroxide, dummy out some of the other metals, or precipitate them out. Nickel-cobalt is a plateable alloy, so I'm not confident that you will be able to plate one preferentially.

Regards,

A. Raise the temperature to 140 °F, and plate at 20 ASF, or higher current density if well agitated. Additives are not needed, but sodium lauryl sulphate might be helpful to reduce pitting.