Sciencemadness Discussion Board

Silver electrolysis purification

Refinery - 4-5-2016 at 14:36

Do I need silver nitrate as electrolyte or can I use copper nitrate as well since it is much cheaper? I would use SS anode and junk silver items as cathode and electrolyse them this way. Would this work?

gdflp - 4-5-2016 at 14:50

No you cannot. The entire purpose of that method is to reduce the concentration of contaminating metals(such as copper) in the silver by selectively dissolving and reprecipitating pure silver metal. If you used copper nitrate as an electrolyte, you would initially precipitate pure copper, then most likely a mixture of copper and silver, but most certainly not the pure silver you're after. You might be able to use a dilute solution of nitric acid, so long as the concentration is low enough that it won't attack either metal, but I am unsure if this will work. In the end, you will end up with a silver nitrate solution as your electrolyte regardless of what you use initially, so you might as well just use it to begin with.

Metacelsus - 4-5-2016 at 16:20

Wouldn't you want to use a junk silver anode and a pure silver cathode? The silver will dissolve from the anode and deposit on the cathode. Impurities will become sludge, or stay in solution. You'll need to keep the voltage controlled to ensure purity. For a reference (with copper): http://chemwiki.ucdavis.edu/Core/Inorganic_Chemistry/Descrip...

[Edited on 5-5-2016 by Metacelsus]

Refinery - 8-5-2016 at 05:08

Nitric acid is currently banned in EU area so I was thinking alternative routes. If must, I will make some HNO3 and go with it then.

aga - 8-5-2016 at 08:23

You can still buy Silver Nitrate and it'll end up cleaner/purer than making it yourself.

I think a member here called 'hegi' was selling some. Top quality too.