I am trying to purify an alloy of sterling silver (containing copper, nickel and silver) into as pure silver as possible. I am currently planning on dissolving the alloy in nitric acid, then precipitating out the silver using sodium chloride.
However I am aware that some of the silver chloride can form AgCl2- and remain dissolved in solution. What would be the best way to get the last little bit of silver out of this solution? I was thinking either electrorefining or thermal decomposition?
Any help would be much appreciated. Thanks ~
Why not cement the silver nitrate on copper, directly converting it to elemental silver? Then you could melt into an anode bar and electrolytically refine it to high purity? Precipitating AgCl will end up being about the same purity as cementing silver on copper, but with extra steps to refine to high purity.
If you plan on processing your sterling silver using the silver chloride method, you could also use HCl to precipitate AgCl, I believe you would convert all the silver nitrate to silver chloride in this case. Reduction can be done by using Kyro syrup or other methods, and once in elemental form you could melt into an anode to refine in an electrolytic cell to high purity.
What is your intent, why are you refining this silver? Is this for a hobby? Or are you wanting the silver for another process? Knowing a little more about your intended purpose might be good in giving you the correct information for your intended purpose.