49001

Nickel plating thickness requirement for bus bars  

June 10, 2008

In a nickel electrowinning cell, the sulphate solution contains 3 g/L chloride. In an effort to protect the anode header bars from corrosion, it has been suggested to plate the cold-rolled steel with nickel. Header bars are 10 mm x 100 mm x 1400 mm. How thick should the nickel be plated? Is there another (perhaps more cost effective) option?

Jason Bornstein
Engineering designer - Mississauga, Ontario, Canada

You need to have a non-porous engineering coating on the buss-bar. I would suggest that as a basic minimum, you have at least 5 microns - this will be sufficient to minimise attack of the substrate through pores, but may not be adequate for any mechanical damage that may be incurred during plant operation. For a safe thickness, I would suggest something around the 25-35 micron range. You may also benefit by using a duplex nickel, where the first layer is about 10-15 microns and the second is 15-20 microns thick.
You would also benefit from looking at the plating specifications for the automotive industry, but unfortunately I do not have these to hand

Trevor Crichton R&D practical scientist - UK

I am not entirely sure what you mean by 'anode header bar'

If any part of the anode is in contact with the solution, the nickel plating will dissolve and plate out onto the cathode.

I would consider replacing the anode bar with copper. This will reduce the voltage drop and hence the running cost.

For electrowinning, I would expect the crude nickel anode to be suspended from a titanium hook or in a titanium basket. Most other materials will be attacked.

Presumably you are also collecting the anode slimes to recover any precious metals they contain.

Geoff Smith Hampshire, England

 

Geoff,
Look at the dimensions of his bar. Consider it to be a flight bar. Copper will not work. I am not aware of anyone that makes stainless steel bar that is filled with copper that would work for him, but that would be the way that I would go if I could find it.

James Watts
- Navarre, Florida