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Pine Beach, NJ

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Carbon anode in nickel electrodeposition

Hi, I would like to recover the nickel from nickel sulphate solution. And in my nickel electrodeposition experiment, I use carbon as anode because of its non-dissolving properties to the solution that will not contaminate the electrolyte and also it is cheap. However, it is easier to be decomposed than nickel and SST anode while the electroplating is running, that resulting the solution having lot of black particle (will that affect the electrodeposition?)

In the industrial area/ metal recycling company, will they also use carbon as anode to recovery metal? Or is it possible to use carbon anode and by adjusting the parameter of electrolyte make the carbon anode performing its perfect electrodeposition?

Hafel [last name deleted for privacy by Editor]
Chemist - Malaysia
2007

A. There are many different grades of carbon for anodes. Some have more impurities than others and some resist the degradation that you refer to better than others.
One answer is to double bag your anodes. This will keep the black stuff out of your solution, but it will not stop the anode degradation.
One approach is to use platinized titanium anodes, but they are expensive. While they last a long time, they are not indestructible.
Two problems that you will run into is the rapid lowering of the pH because of using the insoluble anode which will virtually stop the deposition and the speed of deposition will drop as the metal content of the bath drops. The normal "fix" for this is to use close anode to cathode spacing and very rapid and turbulent solution flow over the cathode.

James Watts
- Navarre, Florida
2007

A. Hi Hafel,
You probably have the wrong type of carbon material -- maybe too porous or having soluble binder. Electrolysis within pores may create oxygen bubbles, thereby disintegrating the material, so try less porous material and a lower voltage. Look for ~pure graphite sheet or plate that is fairly dense, preferably > 1.7 g/cc. Should be strong enough to easily machine without fragmenting. Plating suppliers may have graphite plates with threaded holes on one end for electrical connection.

Probably, lead is a more customary insoluble anode.

Ken Vlach [deceased]
- Goleta, California

Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2007

Thanks for pointing out the problems and giving your constructive solutions, Mr Watts, that is much appreciated. And also, Mr Valch, I will prefer to try the pure graphite plate as you suggest, hopefully I will get what I want.

Besides, anyone knows about the reaction of the carbon anode while it was degraded?

Hafel [returning]
Chemist - Malaysia
2007

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