Electrolysis to refine a dore bar

[Drake Savory]

Sorry if this has been asked (and answered) a million times. A lot of the threads I've read on gold recovery seem to reduce down to extracting the goldish metals from the scrap (board, cpus, etc.) I'm interested more in once you've recovered the metal and have a dore bar of unknown metal proportions. I am reading Hoke's book and studying the chemical method but after seeing a video on how the Royal Canadian Mint gets their .9999 fine gold through electrolysis I am curious how that would work. Of course they gave no details on the solution, voltage, cathode material and how they avoid the other metals like silver from adhering to the cathode.

Anyone have any details on how it is done and if that process would work if you are not already starting out with high purity gold?

 

[butcher]

The gold dore bar anode needs to be fairly pure.

https://www.google.com/search?source=hp&ei=7ygAXdSON6eU0gLS2pWYDQ&q=wohwill+cell&btnK=Google+Search

https://patents.google.com/patent/US625863
https://patents.google.com/patent/US961924A/en
https://patents.google.com/patent/US625863A/en
https://patents.google.com/patent/US625864

 

[FrugalRefiner]

Welcome to the forum.

What you do with a doré bar depends on many things. The first question is what is your purpose in wanting to further refine your material? Are you trying to save the percentage your buyer takes? Are you trying to recover other metals you're not being paid for?

butcher has given you some links to the electrolytic process you mentioned; the Wohlwill cell. But there is a cost. Instead of being able to sell your doré bar, you'll have to cast it into anodes, and wait while it goes through the process. You'll have to tie up more gold in the electrolyte, and in the cathodes. Those are costs that may or may not offset any savings you might achieve by refining in-house.

If you refine to a high degree, do you have an outlet that will pay a premium for your work?

The process is actually relatively straight forward. The question is whether it's worth the effort. It all depends on your particular situation.

Dave

 

[rickbb]

Also if you plan on recovering from escrap and/or karat scrap you can get near .999 gold with the standard chemical processes you will be using anyway.

 

[galenrog]

Gold uses requiring .9999 fine are relatively few compared to those requiring .999. Unless the application requires the higher standard, there is no need to go further.

Time for more coffee.

 

[Palladium]

.995 is good for me! :mrgreen:

 

[anachronism]

.995 is good for me! :mrgreen:

Absolutely correct. 8) 8)

Jon