# From Silver, Copper nitrate, using Copper not salt.



## Hartbar (Jul 17, 2021)

Thank you in advance for any help.
I have done a few sterling silver refining batches using Nitric/Salt/lye/dextrose method.
I’ve searched this forum for info on the alternative method where you use a copper coil to cement the silver from the nitrate form. 
If anyone can post a link or the details on this alternative method, it would make my weekend for sure.
Regards


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## Martijn (Jul 18, 2021)

Just put copper in your silver nitrate and watch the silver cement out on the copper as grey (cement colored) silver. 
Stir a bit every now and then to get all the silver out of solution, and the cemented silver will fall off the copper. Take the copper out before it gets too thin and breaks off in small pieces. Submerge the copper completely to avoid copper oxide contamination. 
Filter when it's done. This can take some time for the last bit. 
The first silver cemented out is higher in purity. The last bit has some copper in it. You could convert the last bit to AgCl
Rinse well and your'e done. 
How do you treat your waste? Do you have a stockpot? Works the same basic way. 

Martijn.


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## Hartbar (Jul 18, 2021)

Thanks Martijn,
I’ve heard this called AP or redux? I’m not sure what those terms refer to?
I assume the cement that’s left is silver oxide and material you can melt after rinsing and drying properly?
Regards


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## Martijn (Jul 18, 2021)

AP is Acid Peroxide. A process that uses copper chloride to dissolve base metals from underneath gold plating. 

Reduction is taking place in the displacement of metal salts in solution into elemental metal on a more reactive metal. 

Putting a piece of metal in a solution containing a mix of metal salts will displace all the lesser reactive metals out of solution. 
The copper trades electrons with the metals in solution and goes into solution itself. Which is oxidation. 
This is explained in dealing with waste. 
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=47&t=1300
Reactivity series
https://en.wikipedia.org/wiki/Reactivity_series

Your cement will be elemental silver. Same as after lye and sugar. Not in oxide form. Ready to melt into shot for the silver cell. 

Martijn.


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## Hartbar (Jul 26, 2021)

Thank you Martijn,
I did a sterling silver batch.
The nitrate I saved to try the copper process with ate through the copper in about 20 mins?
I got some 3/4” copper pipe and cut in half with snips, opened up and dangled in the nitrate completely submerged.
It looks a bit of a mess now, I guess I have a lot of copper in solution now?
How do I retrieve/save my silver cement which is at bottom of beaker.
Maybe I had excess nitric that dissolved copper to quickly?
Regards


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## Martijn (Jul 26, 2021)

If your copper is dissolving (with bubbles coming off), you have used tooo much HNO3. This will eat away the copper and any silver that cemented out on the copper. 
Use the solution to dissolve more silver, until no more reaction occurs. Then cement on copper. One gram of copper will cement out 4 grams of silver (+\-). You could waste all your free nitric in this batch on copper consumption, but that's costly and creating waste. 
How much HNO3 did you use on how much silver? And what kind of source material? 

To retrieve cement: pour through a coffee filter or decant and rinse with boiling water to get the copper salt traces out. You can test for copper traces with ammonia. It turns into a fluffy light blue material. (tiny bit of wash water with tiny bit of ammonia in a test tube) https://www.youtube.com/watch?v=k9_zpXosCPA 

This test result can go in your hydroxide waste stream bucket. 

Martijn.


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## Hartbar (Jul 26, 2021)

I did 22 tr oz of .925 sterling silver. 684 grams. I used about 800 ml of nitric acid, 650 in beaker with distilled water, then added the extra 150ml when action seemed to slow a bit. I used the 1.2 ml of nitric per gram that I saw on forum. There was very little going on and I added a few small thin pieces towards end in an effort to use up nitric.
As long as I can retrieve the cemented silver I’ll be happy.
Regards


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## Hartbar (Jul 26, 2021)

Is there anything you can add to the silver/copper nitrate to remove any excess nitric after dissolving the metal?
I believe urea or sulfamic acid was used by some on forum?


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## Martijn (Jul 26, 2021)

Urea is for the garden. Not for refining. 
Sulfamic acid is used in Aqua regia, not sure if it will work or harm things in silver nitrate. 
Sounds like you did not overshoot much nitric. The most should be gone now. What happens with a new piece of copper?


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## lanfear (Jul 26, 2021)

Sulfamic acid with Nitric will make som H2SO4. That will precipitate out your silver, as silver sulfate.


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## Lino1406 (Jul 26, 2021)

Sorry, Ag2SO4 has meaningful solubility, depends on temperature


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## lanfear (Jul 27, 2021)

Could you elaborate? Just curios. Does it not form Ag2SO4 if it is kept cold?


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## Lino1406 (Jul 27, 2021)

Yes it does, but a meaningful part remains as Ag+ soluble silver even in the cold


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