Sciencemadness Discussion Board - silver from silver cloth?

silver from silver cloth?

Pyro - 9-4-2012 at 12:35

hi,
i was polishing silver today, and thought that it would be an interesting experiment to try and recuperate the silver oxide from the polishing cloth. as it is silver oxide that makes the cutlery go dull, and polishing even a few pieces will make the clean cloth black.
the obvious problems here are: how to get the AgO from the cloth, and how to remove the cleaning product from it.
anyone have any good ideas?
(obviously this is for scientific reasons, not making money as the yeild would be very small)
thanks.

CHRIS25 - 9-4-2012 at 13:54

I am about as knowledgeable at chemistry as I am good at a fighter aircraft. But becaus eof my particular need for silver nitrate I had an idea, probably wrong but hey, I'll throw it out.

Dissolve everything in Nitric acid. Stick some copper pipe into the solution after everything is dissolved, the copper should replace the silver and the silver should precipitate to the bottom. I have a chart which shows that the metal on top will displace the metal underneath it. And copper will dissolve in the nitric acid and precipitate the silver out. I would imagine as a guess based upon the common reagents in cleaning stuff that this should not be a problem. I would check on the web for the ingredients of your particular cleaner, if you have used one. But I personally can't imagine that there is any silver to be had from the cloth. Maybe from a thousand cloths??

Ramblesthegoat - 9-4-2012 at 14:11

Quote: Originally posted by CHRIS25

I am about as knowledgeable at chemistry as I am good at a fighter aircraft. But becaus eof my particular need for silver nitrate I had an idea, probably wrong but hey, I'll throw it out.

Dissolve everything in Nitric acid. Stick some copper pipe into the solution after everything is dissolved, the copper should replace the silver and the silver should precipitate to the bottom. I have a chart which shows that the metal on top will displace the metal underneath it. And copper will dissolve in the nitric acid and precipitate the silver out. I would imagine as a guess based upon the common reagents in cleaning stuff that this should not be a problem. I would check on the web for the ingredients of your particular cleaner, if you have used one. But I personally can't imagine that there is any silver to be had from the cloth. Maybe from a thousand cloths??

Make sure to neutralize the acid before sticking the copper in there, that will just give you more copper nitrate than silver nitrate. Also i'm not an expert, but I don't think silver oxide will react with nitric acid.

barley81 - 9-4-2012 at 14:24

Quote: Originally posted by Ramblesthegoat

Actually, according to Wiki, Ag<sub>2</sub>O does react with acids:

Quote:

A slurry of Ag2O is readily attacked by acids.

You're right that neutralization is good to avoid wasting copper.

One should also be careful to keep the solution slightly acidic so that nothing precipitates out before you add copper. Or, just use less acid. You don't need much for traces of silver oxide on a cloth.

[Edited on 9-4-2012 by barley81]

Pyro - 9-4-2012 at 14:29

im pretty sure there must be a hefty amount of AgO in the cloth, because after polishing a few pieces (3 or 4) a clean cloth is turned black ang gives off black stuff EVERYWHERE.
the cleaner i use is Hagerty's.
so obviously i would first want to remove the cleaner first.

cyanureeves - 9-4-2012 at 15:13

i am also as good a bombardier as i am a chemist or grandmawist but i read somewhere that it is sulfur that tarnishes silver. the cloth would be impregnated with silver sulfate, sulfate or oxide if it dissolves in nitric it will react with salt water and shows up as a white cloudy haze.black tarnish shows up only in silver plated objects but not on sterling or pure silver so it might be silver oxide if the tarnish you have is on sterling or purer.i swear that i have dissolved silver rings that were black but turned out to be high silver content but also i know that karat gold rings are sometimes gold plated for extra shine and maybe silver jewelry is too.

[Edited on 9-4-2012 by cyanureeves]

[Edited on 9-4-2012 by cyanureeves]

Pyro - 9-4-2012 at 15:37

could be sulfur by the way, cos i used to use huge amounts of sulfur for rocket fuel (Zn+S) and guess what i used to fill the rockets? (yeah, our silver spoons)
but could someone please explain the best process of extracting the Ag2O and/or Ag2S?
i'm not sure if its sterling, but its Christofle (cutlery)

weiming1998 - 11-4-2012 at 05:53

The best way of extracting is to use acids. If it is mainly Ag2O/Ag2S on that polishing cloth, almost any acid will do, just make sure you have proper ventilation (H2S produced)
If it is mainly metallic silver, on the other hand, your best choice would be nitric acid.

The solution can then be neutralized using NaOH or Na2CO3. Then filter and dry. That's active Ag2O/Ag2CO3 for if you want silver for chemistry purposes. If you just want the metallic silver, heat the precipitate in any random old soup can (make sure it's clean though!) on the stove or on a bunsen burner on high heat. After a few to few tens of minute of heating, you should be left with powdered metallic silver.

If the cloth contains mainly metallic silver and you don't have nitric acid, though, you could try placing the cloth in a soup can (again) and char the cloth to dry carbon(ventilation). Then mix your powdered cloth with molten potassium nitrate and after the reaction, dissolve the residue and filter.

[Edited on 11-4-2012 by weiming1998]

Pyro - 25-4-2012 at 04:28

i have many acids, I am sure there is no metallic silver on it. i'll try it,
thanks

CHRIS25 - 25-4-2012 at 06:03

Quote: Originally posted by Pyro

could be sulfur by the way, cos i used to use huge amounts of sulfur for rocket fuel (Zn+S) and guess what i used to fill the rockets? (yeah, our silver spoons)
but could someone please explain the best process of extracting the Ag2O and/or Ag2S?
i'm not sure if its sterling, but its Christofle (cutlery)

Hi Pyro, I am not sure if you already know this, but just in case, Sterling silver will have usually 925 engraved somewhere if not I have a complete list of silver hallmarks for you. But if it is cutlery I doubt very much that it is solid 99% silver, it would bend too easily in the steak.

unionised - 25-4-2012 at 11:47

A couple of points,
Firstly, the black stuff that forms on silver is definitely the sulphide not the oxide.
Secondly, I rather suspect that a lot of the black stuff on the cloth is finely powdered silver.

There are other things in the silver polish ( cerium oxide is one possibility) that would make things a bit more complicated.