Chemical Forums

Please login or register.

Login with username, password and session length

Sponsored links

Pages: [1]   Go Down

Author Topic: Best Purification of Sterling Silver Methods?  (Read 924 times)

0 Members and 1 Guest are viewing this topic.

knowncovvert

  • Very New Member
  • *
  • Mole Snacks: +0/-0
  • Offline Offline
  • Posts: 1
Best Purification of Sterling Silver Methods?
« on: June 22, 2013, 02:32:43 AM »

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 ~
Logged

Enthalpy

  • Chemist
  • Full Member
  • *
  • Mole Snacks: +47/-27
  • Offline Offline
  • Posts: 682
Re: Best Purification of Sterling Silver Methods?
« Reply #1 on: June 27, 2013, 04:35:55 AM »

Electrorefining is efficient: 99.999% pure copper is made that way, which separates silver
http://en.wikipedia.org/wiki/Copper_extraction_techniques#Electrorefining
as a by-product of copper mining.

But it has drawbacks...
- Amount of electricity
- Size of electrolysis cells. Duration.
- It must require know-how.

Could you distill the alloy under low pressure?
The standard method to refine magnesium uses that http://en.wikipedia.org/wiki/Pidgeon_process
Your elements spread nicely: Bp (1 atm): Ag 2162 °C - Cu 2927 °C - Ni 2913 °C.
Reduced pressure would make the temperature compatible with ceramics like ZrO2 and maybe Al2O3.
Distillation would take far less energy and time than electrorefining.
Logged

NobleMetalWorks

  • New Member
  • **
  • Mole Snacks: +1/-0
  • Offline Offline
  • Posts: 8
Re: Best Purification of Sterling Silver Methods?
« Reply #2 on: August 25, 2013, 12:13:54 AM »

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.

Scott
Logged
Pages: [1]   Go Up
 

Mitch Andre Garcia's Chemical Forums 2003-Present.

Page created in 0.04 seconds with 23 queries.