Separation of Cu-Ni alloy by CuCl precipitation
Im back! I happened to need a lot of Cuprous Chloride for cheap and i have a lot of old coins laying around made of a Copper-Nickel 8:2 by weight if i
remember correctly though i am now unable to find the reference. I see this subject resurfacing fairly often so i think someone will appreciate this
method.
To separate the coins i dissolved half of them in azeotropic Hydrochloric acid by refluxing with an aquarium air bubbler. To start the reaction a
small amount of Hydrogen Peroxide was used. The other half of the coins were then refluxed with the resulting solution without an air bubbler. The
solution was periodically poured off, filtered and poured back into the reflux apparatus to remove the formed Cuprous Chloride. After the Cuprous
Chloride formation significantly slowed down the solution was boiled to dryness with some copper wire, dissolved in a large amount of water and
filtered. A small amount of very fine Cuprous Chloride remains, it passes straight trough a 10-15 micron filter but settles so it can probably be
separated by decantation. While not giving very pure Nickel (II) Chloride it gives fairly pure Cuprous Chloride with very few reagents. I am sure
there is room for improvement hence this post.
The reactions are:
2 Ni + 4 HCl + O2 ---> 2 NiCl2 + 2 H2O
2 Cu + 4 HCl + O2 ---> 2 CuCl2 + 2 H2O
Cu + CuCl2 ---> 2 CuCl (The reaction in the second stage)
2 CuCl2 ---> 2 CuCl + Cl2 (During the heating the Cupric Chloride should decompose rendering the last copper fairly
insoluble)
Some notes:
Use azeotropic acid to reduce losses and fumes.
Heat as high as possible when boiling to dryness to decompose soluble Cupric Chloride
Coins can be hard to fit in a RBF; i recommend bending them after annealing them.
If you do not anneal them wash the finger fat away.
I did not write specific amounts nor yields because i lost my original notes. 
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