Refining gold with copper

I refine gold wiht copper not with silver what should it copper ration should be ? Same as calculation as silver or it diffrent ?
silver calculation is

100 gr 730 karat
100*.73=73g pure gold
100-73=27 deslove metal
73*3=219
219-27=192g silver
192+100=192 g silver for refining 100gr 730 karat gold.
Is this calculation also work if i use copper behalf of silver ?

talalstuvs,

I have never tried using copper in the in-quartering, and parting process.
I see no reson it would not work, and no reason to change your math.

You will use more nitric acid than if you used silver.

Because I have not tried this before if I was to try it, I would try 2 batch's one with less copper.
Looking to see if I had gold left in powder or if left in clump (could crush easily)..

You may find you can use less copper than if you used silver, or it may take a little more.
Small experiments and you will know.

It is worth noting that beyond the fact that copper will require 3.4 times more nitric in order to be digested than silver, that copper will not remove platinum from your karat gold. Silver is used as it acts as a carrier of the PGMs from gold and is less costly in nitric consumption. The greater value for me is in removing PGM before AR digestion as clean separations are more difficult after AR when they are present.

Good point as usual Oz, thank you, also the silver can be used over and over until it is loaded with PGM.
Silver is not that expensive as scrap (sterling), and can also be refined and sold if needed.