Electrochemistry STERLING SILVER - removal in sulfuric acid cell

[virtalex]

Below in this forum branch are some topics concerning sulfuric cells but they speak about gold refining, However I need to get out silver to 99,99%. searched with silver+cell and silver+coating+removal, but did not find the info I need.

Please give me a thread or share experience on conditions to remove silver coating from sterling cutlery to produce initial material for further refining (dissolving in HNO3, electrolysis in nitric cell).

base alloy is Zn/Ni/Cu ca 90% + Ag coating ca 10%

Questions>
1 Which solution to use - acids, concentrations, solution density?
2 reaction parameters - temperature, voltage and current density (mA/sm2)
3 anode/cathode - can I use titanium baskets that I used to use for zinc plating as anode baskets and stainless steel as cathode? Graphite is something I dont have.
4 what should be anode/cathode surface ratio?
5 should I use anode or cathode bags?

Thanks.

 

[philddreamer]

Welcome to the forum!

There's some reading here:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=13976#p140259

Phil

 

[goldsilverpro]

There is sterling cutlery which is solid 92.5% silver/7.5% copper. There is silver plated cutlery which is silver plated copper alloy. Two totally different things.

I have spent a lot of time lately telling people that stripping silver from copper is a fool's errand. If you spent a little time searching the forum, you might find 100 threads that explain the situation in detail. Here's the latest one.

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=14106

 

[virtalex]

Thanks for information. Here is an interesting thread http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=12530

Concerning feasibility of the refining from silver plated sterling. It depends very much on the price of the scrap. It works fine form me. My issue was thet I used to strip silver chemically in warm HNO3, but the silver tends to settle back on the scrap from the solution and I dont want to dissolve the whole stuff, since it takes unnesseccary amount of HNO3 (which is cheap in my country but still - penny saver the buck).

 

[goldsilverpro]

Sterling is 92.5% silver. Why would anyone silver plate it?

 

[MysticColby]

Sterling is 92.5% silver. Why would anyone silver plate it?

isn't that what pickling effectively does? dissolve the surface copper, leaving pure silver for a brighter shine.

 

[goldsilverpro]

Sterling is 92.5% silver. Why would anyone silver plate it?

isn't that what pickling effectively does? dissolve the surface copper, leaving pure silver for a brighter shine.

There is an old leaching method for increasing the gold percentage on the surface of karat gold, but I've never heard of it being used for sterling.

 

[FrugalRefiner]

isn't that what pickling effectively does? dissolve the surface copper, leaving pure silver for a brighter shine.

Pickling is used in jewelry making and repair to dissolve any metal oxides (fire scale) that have formed on the surface during heating. It's purpose isn't to dissolve any part of the alloy, just any base metal oxides on the surface.

Dave

 

[virtalex]

Sterling is 92.5% silver. Why would anyone silver plate it?

sorry for my english.. perhaps sterling not correct term.. I actually meant silver plated copper alloy cutlery (spoons, forks, small plates, etc)

 

[Harold_V]

Sterling is 92.5% silver. Why would anyone silver plate it?

sorry for my english.. perhaps sterling not correct term.. I actually meant silver plated copper alloy cutlery (spoons, forks, small plates, etc)

That would be considered silver plate, not sterling. An easy mistake to make if you don't use English as your first language.

Harold

 

[Kruegerrand]

I'm working myself with silver plated items too.I found a local refiner who is charging $35 per kg plated items to get the silver out of it.Not cheap but its working.