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Author: Subject: Silver from silver plate
NEMO-Chemistry
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[*] posted on 12-1-2018 at 19:47
Silver from silver plate


Is the electro method the best way to recover silver from EPS?

I have collected alot of it, some says nickel on it and I have a thing for Nickel and Silver at the moment!
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vmelkon
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[*] posted on 16-1-2018 at 09:28


React with nitric acid to get a salt solution. If there is iron or similar element, the Ag+ ions would get reduced back silver. When the entire metal is reacted to obtain a nitrate solution, add a chloride solution to precipitate AgCl.

Then exposure to light or heating it would reduce the Ag+ to silver and the chlorine liberates into the air.




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[*] posted on 16-1-2018 at 09:31


Also, direct heating of AgNO3 will reduce it to elemental Ag. This can be much faster and easier.
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[*] posted on 16-1-2018 at 10:37


So the base metal dosnt react? I am not too sure what they use as a base metal on old spoons etc
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MrHomeScientist
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[*] posted on 16-1-2018 at 11:25


The nitric should dissolve everything, including the base metals. Adding NaCl precipitates only AgCl, since all other metal chlorides are soluble. This purifies the silver of whatever other metals might be present.
For example sterling silver is an alloy with copper: after dissolving in acid and adding the salt, you're left with solid AgCl and a solution of copper nitrate.
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[*] posted on 16-1-2018 at 13:03


The conversion of AgCl to Ag by light alone is very slow and very uneven because light doesn't penetrate very deeply into the powder. A much quicker method is to add concentrated NaOH to form AgO. This can optionally be converted into metallic Ag by adding a reducing sugar (corn syrup is typically used), or it can be decomposed into Ag directly by heat.

Another method to get the silver out of the nitric acid solution is to add metallic copper. If you have an excess of acid, at first the copper will dissolve. But if you add an excess of copper, it will then reduce the silver, yielding metallic silver directly. Copper is not able to reduce the base metals.




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[*] posted on 16-1-2018 at 14:06


ok thx i understand now
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[*] posted on 16-1-2018 at 14:19


The big problem is you waste a lot of acid dissolving the base metals.
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[*] posted on 16-1-2018 at 14:23


Quote: Originally posted by phlogiston  
The conversion of AgCl to Ag by light alone is very slow and very uneven because light doesn't penetrate very deeply into the powder. A much quicker method is to add concentrated NaOH to form AgO. This can optionally be converted into metallic Ag by adding a reducing sugar (corn syrup is typically used), or it can be decomposed into Ag directly by heat.

Another method to get the silver out of the nitric acid solution is to add metallic copper. If you have an excess of acid, at first the copper will dissolve. But if you add an excess of copper, it will then reduce the silver, yielding metallic silver directly. Copper is not able to reduce the base metals.


Ag2O (Not that it matters much)
You can get the same effect by mixing the AgCl with sodium carbonate and melting it.
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[*] posted on 16-1-2018 at 14:33


Quote: Originally posted by unionised  
The big problem is you waste a lot of acid dissolving the base metals.

Not a bad way to 'use' some Nitric acid then ;).
Especially as you wouldnt need alot of silver or silver nitrate to tally with your stock list.
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[*] posted on 17-1-2018 at 16:28


Quote: Originally posted by unionised  
The big problem is you waste a lot of acid dissolving the base metals.


I suppose you can collect the other metal nitrates.
Heat it with conc H2SO4 to get some nitric acid back.

And if you really want to continue, heat the metal sulfates to some high temperature to get some SO3 vapor. Direct the SO3 into some low conc H2SO4.




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