# deplating silver from silverplated items



## mocodos

hello everyone,

i will share an experiment, to deplate silver from plated items, with you:
it´s not from me, i have found a little about the experiment, and now i will reproduce this.



You need:

distilled water
cooperplate
silverplated items
sodium persulfate (Na2S2O8)
electro cell like silvercell

60g sodium persulfate per liter
Voltage 5-12 V 

i testing some setups, here are the results:

first i dissolving some copper in sodium persulfate solution.
next i start the cell with silver plated items as anode
and a copperplate as cathode.
after the solution is saturated, some removing of copper from cathode is needed,
you can cement the silver with a copperplate from solution out.

i testing some setups, and i have now not the 100% right way, but you can see the results.

you can test this and try make the process better, perhaps we can find the best way?!

mocodos


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## mocodos

next pictures:












mocodos


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## mocodos

next pictures:












mocodos


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## mocodos

next pictures:





i testing some of setups, so if i find a new better configuration, i´ll post it here.

mocodos


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## philddreamer

Very nice, Mocodos!

Phil


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## Geo

so if im not mistaken, your electrolyte is copper sulfate? you first saturate the sulfate solution with copper?


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## mocodos

yes, first i add some copper to the sodium persulfate solution, after the solution is 
saturated, (it turns blue color, and no more copper is dissolving) you remove the undissolved copper and can start the process.

mocodos


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## qst42know

That's an interesting experiment. 

How many pieces can be stripped before you need to cement?

Is this solution reusable?


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## mocodos

i started the experiment with 0,5 liter. after the solution is not transparent, dark blue/green, and you can´t look through, 
i started the cementation part.
now i have a 6 liter plastic bowl, it turns longer to saturate the solution, but you have more dissolved silver in it.
the cementation need some hours, but with larger pieces of copper, you can get more silver at one time.

the solution is reusable, ("endless" i think) but little goes away, from filtering, removing cooper from cathode,...

mocodos


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## qst42know

Would a copper bar hung from the glass, not part of the electrical circuit, cement silver while this is running?


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## Geo

how is the silver in suspension? is it converted to silver sulfate? after it is cemented what would the purity be? many questions. i, mistakenly apparently,believed sulfuric acid could not hold silver in suspension and that it would self precipitate at a certain point.


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## mocodos

qst42know said:


> Would a copper bar hung from the glass, not part of the electrical circuit, cement silver while this is running?



yes, it would, you can see it here

in the right side is a copper bar, as a not a part of the electrical circuit, and cementing starts immediately

mocodos


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## mocodos

Geo said:


> how is the silver in suspension? is it converted to silver sulfate? after it is cemented what would the purity be? many questions. i, mistakenly apparently,believed sulfuric acid could not hold silver in suspension and that it would self precipitate at a certain point.



i´m not a chemist, i thing it is presented as silver oxide and in a colloidal form (after dissolving from anode) here.
i did at test, 100 ml distilled water, 20g sodium persulfate, 1g silver from cementing, after adding silver
to the solution, the reaction starts, silver was converted to silver oxide, it was dark on the ground, after few minutes, the solution 
was gray/black in color an was not transparent. after adding a copper piece, the cementing starts, after the solution is saturated from the copper piece. 

if the cell have no current, or you have only a anode or only a cathode in the solution, the cementing process start immediately.

in future i will test few grams, but after reading about this process, the purity would be about 99% -99.9%.

mocodos


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## qst42know

> but after reading about this process, the purity would be about 99% -99.9%.



Is there a web document to read?


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## mocodos

qst42know said:


> but after reading about this process, the purity would be about 99% -99.9%.
> 
> 
> 
> 
> Is there a web document to read?
Click to expand...



here is the source, but it is in german 
http://www.experimentalchemie.de/versuch-051.htm

"Nach etwa 20 Minuten hat sich auf der Elektrode ein ocker-farbener Überzug gebildet, der nach weiteren 2 Stunden zu einem fein verästelten Gebilde ("Dendriten") herangewachsen ist ("Silberbaum"), welcher jetzt etwa die Grösse eines Tischtennisballes erreicht haben kann.
Dieser Silberbaum kann sich rund um die Elektrode verteilen, er kann auch wie ein Vorhang bis zum Gefässboden hängen. Das Resultat besteht aus elektrolytisch reinem Silber und wird in einem weiteren Gefäss (altes Trinkglas) unter dest. H2O gelagert."

translated with google:

"After about 20 minutes has on the electrode an ocher-colored coating formed, which is after another 2 hours to a finely branched structures ("dendrites") grew up ("Silver Tree"), which may have now reached about the size of a ping pong ball.
This silver tree can be distributed around the electrode, it can hang like a curtain to the vessel bottom. The result consists of electrolytically pure silver and distilled into another container (old drinking glass) below. H2O stored."

mocodos


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## Ian_B

Roughly how long would it take to deplate a single silver plated spoon in this set up? a few seconds/few minutes/few hours ?

what is the voltage that your setup is using?

thank you for the great pictures they answer a few questions


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## Goldfinger4

I used sulfuric acid 37% as electrolyte and a 5V/25A PC power supply for 6 spoons and 6 forks (appr. 30g fine).
The other electrode was stainless steel. Sulfiric acid has its highest conductivity at 37%.
I let it in the acid for 4 hours and the result was 35% silver. I wanted to be sure that I got all the silver, I think 50% are also possible.

The method described above says "some removing of copper from cathode is needed" - the layer on the cathode is also partly silver.
You only extracted the silver that is still in the solution, which is less than 4g/l because silver sulfate is not easily dissoluble.
I hope you did not throw the "copper" away 
The silver you extracted may have a purity of around 98-99%. Pure silver can not be refined by cementing with copper.


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## mocodos

hello goldfinger4,

thanks for the info  

this way that I write is only one way, must not be the best,
I wanted to reproduce this from an experiment.

I think in order to process the mass of silver items, silver items must be melted as anode and processed in sulfuric acid cell/copper cell.
like in the industry.
the higher the voltage the higher the contamination of impurities at the cathode.

mocodos


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## Ian_B

If you have any more pictures of your setup or while your cell is running I would love to see them 

thanks Ian


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## ericrm

most of my silver plated item are silver over zinc and not silver over copper ,did you have probleme with the zinc(i think it is reacting with sulfuric acid)...


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## watcher6880

Where can you buy sodium persulfate? I checked refiningchemicals.com and couldn't find any. Also would the average Joe be able to get this without complicated channels like purchasing nitric acid?


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## butcher

Look for supplies in etching circuit boards.
http://www.circuitspecialists.com/4101-1kg.html

http://www.ebay.co.uk/sch/i.html?_nkw=persulphate&_sacat=0&LH_PrefLoc=2&_dmpt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&_odkw=persulphate&_osacat=0&_trksid=p3286.c0.m270.l1313


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## watcher6880

Just wondering step for step how this process works... I have been checking out the pics but seem to be getting confusion from them. The sodium persulfate comes in crystal form if I am correct(?) What needs to be added to this to make the solution? Sorry I am not very knowledgable of the reverse electroplating process as I am familiar with the AR and Silver Nitrate process.


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## watcher6880

Anyone?


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## lazersteve

I've used the sodium persulfate etch to dissolve the copper out of some finger boards. 

It tells the proper mix with water right on the side of the jug.

It turns out it's slow for etching copper and expensive to boot, so now I have a gallon jug of the crystals and no use for them.

I've never tried using it as the electrolyte in a silver stripping cell.

Steve


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## Geo

can you substitute dilute sulfuric acid to make the copper sulfate electrolyte?


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## watcher6880

I wondered that Geo.


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## Goldfinger4

Yes you can use simple battery acid. The electrolysis will dilute copper and silver.
The conductivity of the electrolyte will rise until it is saturated with copper and silver ions.
Sodium persulfate is used to etch circuit boards (without electrolysis).


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## Pally

Hello from Canada............
I have a jar of suphuric acid (started out as two gallons) and have been blowing the plated gold off of items i picked up here and there......
I also have a great mess of silver plated items to strip......
Do you think that mere copper sulphate salts desolved in distilled water is sufficient for electrolyte?
Or would you reccomend the persuphate?
If you have any idea how to get the gold out of my solution id like to hear it too....thanks


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## nickvc

Pally sulphuric acid can't dissolve gold on it's own, if you use concentrated sulphuric and build a striiping cell then you can dissolve it but only for a short period of time as perasulphuric acid forms by the anode but converts back to sulphuric as it moves away dropping the gold as a black powder.
If you have a sludge in the bottom of your container it's your gold.


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## Harold_V

What Nick said. Be advised, because the gold that is recovered is very finely divided, it won't be colored like you expect. The black sludge you see _is_ the gold, albeit not really pure. You must wash, dissolve, filter and precipitate the gold, then wash properly before you can consider it pure, and even then it may require a second refining. All depends on your objective. 

Harold


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## Pally

Lots of gold flakes and micro particles can be seen floating in the acid....
These i filtered out and all the bottom sludge i have soaking in the empty glass cell jar......
I plan to settle it out anf pour off the water as much as possible, then dry the rest up.
when it turns into dry material could mercury pick up the gold out of it?PS. 

Ps i am going to start deplating the silver items as suggested with battery acid...the same stuff i blew the gold off with....
I plan to use it because it is already blue with copper contamination .....
Should i mix 50/50 with distilled water? or should suphuric battery solution be ued full strength?
(i have new electrolyte from the dodge dealers...)
if using new electrolyte should i run some copper plate then try the silver after the acid goes blue green?


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## Harold_V

Pally said:


> when it turns into dry material could mercury pick up the gold out of it?PS.


Why on earth would you want to use mercury? That makes NO sense at all. It also makes no sense drying the material, unless you intend to incinerate. What purpose would that fulfill? 
If you don't understand what you've been told, please do yourself a favor and stop processing. Read the forum and Hoke's book, until you understand what you should be doing, and why. You'll be glad you did when the light comes on.

Harold

PS--
Mercury has NO PLACE in refining. 

None! 

There isn't one reason why you should need mercury.

Please read the forum on the sulfuric stripping cell. One does NOT use battery acid, for it is too dilute. It can be used after evaporation, however. It's all on the forum.


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## tek4g63

Has anyone else tried this using the diluted sulfuric acid? I have about 10lbs of 4X plated silver ware that I would really like to try this with. I was hoping that someone much smarter than myself had mastered this process.

Thank you for any and all input.

Thad


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## Tankman

Can this method be used on larger industrial type silver plated pins?


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## etack

You mean like these? these came from 3phase connectors and had two long gold pins in them 8) .

if they are all cooper use them to cement your silver. If you look for silver plate when your out only buy silver over copper so you can get the silver back that way. the other silver plate you can throw into old Ap and have it work on it that way. There is no cheap what to strip silver or it would be bought more frequently as silver bearing scrap.

Eric


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## Tankman

etack said:


> You mean like these? these came from 3phase connectors and had two long gold pins in them 8) .
> 
> 
> 
> Yes, very similar to those. They are pins from Compaq/HP bus bars and are copper underneath. Thank you for the advice on using them for cementing silver. 8)


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## solar_plasma

Just for the completeness, CuSO4 instead of copper dissolved in sodium persulfate works. Where the CuSO4 comes from doesn't matter.

Is there anybody who was able to optimize the process? I am running it since some days, after some testing, now with about 8V at 10A. I get about 20g silver per day of active process from 24 pieces with about 100g silver plating on about 1 kg of material. This seems to be a bit slow to me.


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## butcher

solar_plasma, 
I tried an experiment like what you are doing, trying to remove the silver from plated silver spoons and forks, I tried a couple of different electrolytes, copper sulfate seemed to work the best and was the safest, (I also had plenty of copper sulfate from other processes), I did not use or have a membrane bag (so your results may or may not prove different than mine), I could remove the silver along with some copper and other base metals from the plated articles using this method, which gave me a mixture of silver and copper as the results, with these fluffy powders I had to use other acid treatments to dissolve the copper from the silver, to reclaim the silver, the only benefit I seen was I was able to remove the silver plate without dissolving all of the metals in the spoons and forks, but in the end I cannot say I made any progress, as the amount of silver recovered for all of the time trouble and acids and other chemicals I used, probably cost me more than anything I gained in silver, so basically unless I learn something different about this process I do not think I would try it again, I am interested in seeing how you do with your experiment, and seeing if your results are different than mine were, of if you can make it work better than I could.


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## solar_plasma

> I did not use or have a membrane bag



With membrane I had a bad conductivity, so I dropped it again for this first experiment. BUT with membrane the copper crystals got very heavy and would not fall apart, when removing the cathode. Quite interesting. I use my experiences with this first sample to find out how I will construct my next cell. I am very optimistic.

Small contaminations of the silver with coppertraces can obviosly be treated by the dissolved AgSO4. I just remove the electrodes for a night and let the silver cement on the copper traces.

I think you are right, this cell is nothing to earn money with, not if you count the hours spent maintaining it


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## solar_plasma

> i did at test, 100 ml distilled water, 20g sodium persulfate, 1g silver from cementing, after adding silver
> to the solution, the reaction starts, silver was converted to silver oxide, it was dark on the ground, after few minutes, the solution
> was gray/black in color an was not transparent.



Just found something interesting related to this post: http://en.wikipedia.org/wiki/Silver(I,III)_oxide

and I read, that there always will be some persulfate left when copper is edged in persulfate. Is it possible, that if pure CuSO4 is used, the sulfate partly would be reduced to persulfate? Is copper persulfate green? ..since my solution shifts between green and turkise and sometimes a black powder occurs on the silver.

Edit: green colour is probably nickel, black powder probably cementet copper

Whatever....somehow it works.


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## ilikesilver

curiosity killed the cat, if AP will disolve copper, then why wont AP work on this same scenario? tim


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## etack

ilikesilver said:


> curiosity killed the cat, if AP will disolve copper, then why wont AP work on this same scenario? tim





etack said:


> You mean like these? these came from 3phase connectors and had two long gold pins in them 8) .
> 
> if they are all cooper use them to cement your silver. If you look for silver plate when your out only buy silver over copper so you can get the silver back that way. the other silver plate you can throw into old Ap and have it work on it that way. There is no cheap what to strip silver or it would be bought more frequently as silver bearing scrap.
> 
> Eric




You want to keep as much of the junk as you can out of your silver. The white "brass" is full of other stuff lower on the series chart so it will cement out Cu into your silver. in the AP he silver will flake off and sit at the bottom of the bucket. this can also be done with used sulfuric acid that has water in it.

Eric


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## solar_plasma

I see the benefit of this cell in it's safety and thereby I agree with butcher. This is a process I can do at home with good conscience. Most of the other processes I prefere to do under real laboratory conditions.

For sure my silver isn't pure, but it is light grey and sparkles. If it is not pure enough for further electrorefining, I thought of treating it with AgNO3 or AgSO4 to dissolve basemetals, has anybody tried this?

The gained copper will be contaminated with silver and basemetals. I will keep it and thought of using it for inquartation, later I have come so far. Ofcourse I will test it before I do that.

*IMPORTANT NOTE: Don't use the flatware for cementing like it is described on http://www.experimentalchemie.de/versuch-051.htm, but only clean cobber !!! Since most of the flatware contains zink and nickel, this will cement the Cu from your electrolyte, which is getting more and more green and at the cathode the cobber becomes more and more dark from impurities. The cemented copper will contaminate the cemented silver, which gets a brownish tint. If this happens, you can add a large amount fresh CuSO4. You will get light red copper at the cathode again.*

Sooner or later the electrolyte will be saturated by zink and nickel. I will have to find a proper way to handle this.

Edit: From a profits view, it may be better to mill the silver off mechanicly if ugly white brasss is beneath the silver and then process it the wet way. For plated cobber this method will work cheap and easy. Just use a small distance, high electrolyte concentration, maybe a bit sulfuric sometimes and have a large electrode area. Then you can run it with 3 V and 10 A. Then the cobber cristalls will be very nice too.


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## solar_plasma

Well, I have learned much from my version 0.x cells, now I present my version 1.0. First time in progress. 8) 

At this time it runs with 5V and 4A.


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## solar_plasma

The new boxed cathode design helps avoiding floating lumps of cobber contaminating the silver.


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## solar_plasma

But it is still a nasty work!


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## butcher

I Do find the experiment interesting.


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## solar_plasma

Thank you, Butcher!


*Safety note: There is not only nickel, but probably also cobalt (violett sulfate) in some flatwares. Cobalt sulfate is category 1 cancerogene! Make sure not to let aerosoles getting into the air. I covered my cell with a plastic bag.*


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## solar_plasma

I advise, equal to good practice with other scrap, as far as possible to use equal items as the anode. Flatware is made of most different alloys, which naturally react very different. Some finishes, like "mangasil", which becomes black without being attacked very much, needs to get brushed with a steel brush once in a while. I guess, that the black layer is passivating them a bit.


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## solar_plasma

I need your thoughts:

I am thinking of using an aquarium filter pump with weak flow to suck silver sufate containing electrolyte (max. 8g/l - because of the other sulfates, much less) out of the cell, let it pass through some copper in a larger vessel with extremely low flow and back to the cell. In and out should have the same distance from the electrodes, maybe behind the anode.

Benefits: More liquid=more silversulfate dissolvable / continuously fresh electrolyte / less contact with the cathode copper / less contact with the non-copper basemetals at the backside of partly dissolved anode

Do you think, there is a good chance, it would work or have I missed something?


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## solar_plasma

Update:

Now I use two cathodes, one in front of the anode and one behind, because I encountered cementation on the back of the cathode. The cell runs constantly with 3,3V at 10,7 A, no gas and it stays pretty cool.


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## solar_plasma

Everyone who is interested in this subject, http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=54&t=15614&p=185238#p185238, in the bookhttp://uctm.edu/departments/MCMT/BG/E-library/Extractive_Metallurgy_of_Copper_-_G._W._DAVENPORT.pdf in chapter 16 is all you need!

thiourea/HCl is not absolutely necessary in small set up's with my cathode construction, which I now again have furtherly improved
[thiourea is a compound in some silver cleaning bathes, cat.3 cancerogene...which should not be the biggest problem in this poisonous heavy metal witch brew]

I am not trying to strip the silver anymore, but I just let the whole anode dissolve

I don't cement anymore over night, I just let it work.

I reiuvenate the electrolyte by thinning with washwater from the bucket in which I wash the cathode once or twice a day and by adding sulfuric

when the ampere are falling, I adjust with small amounts concentrated sulfuric.

*The cell works and it's eating like a swarm of piranhas. * 8)


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## solar_plasma

The electrolyte is quite quickly used up with many plated alloys, obviously quite quicker when there is a high zink content. This had to be expected.

To take the washwater from the cathode copper bucket (I added a bit sulfuric from time to time) will not give enough Cu++ cations, though it's nicely blue in colour. My challenge will now be to find the easiest, fastest and cheapest way to form new CuSO4. As far as I read on the forum, this is not as trivial as it seems to be. I think of five possibilities:

Cu (powder) + H2SO4 + H2O2 (read also Caro's acid! - only use diluted agents! only small amounts H2O2! Handle with care!) * EDIT: works fine to clean silver-copper blends (brown-grey), the remaining CuSO4 solution will probably contain a little AgSO4 and will be added to the electrolyte again. Acid fumes and violent reactions possible!http://en.wikipedia.org/wiki/Piranha_solution* 
2 Cu + O2 -> 2 CuO // CuO + H2SO4
Cu + HNO3 + H2O2 // CuNO3 + NaOH // CuOH + H2SO4
Cu + AP or A/Cl // CuCl2 + NaOH // CuOH + H2SO4
Cu + Na persulfate

Ofcourse all will work. All have disadvantages. I just don't know, what is most practical.* I will find out, though if anyone likes to comment, you are welcome.*

Since electrodeplating is very fast in the beginning and than slows much down, I could imagine, that it would be a good solution to simply slowly let dissolve the residual metal pieces in acid in order to get the last gramm of silver. 

Another thought of mine: Since the used electrolyte is low in Cu++ (close to nothing) and probably high in nickel, maybe it could be used with a nickel cathode on the mostly stripped anode. The anode slimes will then be a blend of cobber and silver and would have to be dissolved in HNO3. But this could at least save some amounts of acid, since Ni and Zn are separated. But since I have no nickel plates, I cannot try it soonly.

BTW to all, who think, they could earn money on this, - forget it :lol: I have bought the scrap for under 50% of spot price and all the gloves, chemicals and electricity alone have eaten the profit.


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## butcher

copper oxide mixed with silver oxide, can be formed from these powders, wash well dry and incinerate.

The copper oxide will dissolve easily into most acids.

Silver sulfate has a low solubility with other metals in solution there may not be much silver in solution, (you always can use the chloride test on a small portion).

copper oxide will also dissolve in HCl, where silver forms the insoluble chloride.

Decisions, what do we think will work best for our situation.


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## solar_plasma

> copper oxide mixed with silver oxide, can be formed from these powders, wash well dry and incinerate.



I think this one will be a good choice for bigger amounts of blends with much copper and little silver. I used 4M H2SO4 (about 35-40% I guess) with very small amounts of 33% H2O2 carefully added on estimated 60-80% silver and it worked rapidly. Though next time I will dilute the H2O2 first. Although I expected possible violent reaction and ofcourse started with a tiny probe, I was surprised on the generated heat. Thanks, Butcher! I will try this.


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## solar_plasma

solar wrote:


> The new boxed cathode design helps avoiding floating lumps of cobber contaminating the silver.



The recovered brown powder on the left yielded about >50% silver after the 1. refining by dissolving in HNO3 and cementation on copper. I will post the yield from the light grey powder on the right as soon as I have processed it.


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## rewalston

looks good solar, can you describe how you constructed your sell? I have a lot of silver plated "silverware", can't sell it or trade it so might as well play with it.

Rusty


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## solar_plasma

If there is only copper beneath, just run it like a traditional copper refining cell. If there is Cu-Ni-Zn beneath, it is best to stop before the reaction mostly attacks the basemetals, because they quickly foul the electrolyte. Otherwise, you could just use fresh electrolyte every day, if you have enough CuSO4, then you can just go on until the anodes are completely dissolved. Then you have a lot of liquids to treat for reuse.... nasty.

You could hammer the pieces flat to have a homogen distance.
The distance between anode and cathode should be short (higher Amp and less electrolyte), but long enough to prevent short circuits. Under 2V at 6-8A worked fine for 12 big spoons. If you use a membrane like goretex, it will become very slow, but you get small hard and dense copper crystals at the cathode without using additives. I never tried additives like thiourea and bone glue, that's what they use in plants to get a dense copper deposition. The cathode can be made of copper- or stainless sheets. Also in plants they circle fresh electrolyte into the system all the time and treat the used electrolyte for reuse. The system should not get to cold, I think 30-40°C are fine. Prevent producing H2 by setting the voltage down, - it would be a loss of energy and produces a fine invisible fog,that probablyis not very healthy. Therefore cover the system, when you leave it after loading or cleaning.

When the electrolyte is loaded with silver sulphate, remove all electrodes and cement it oout on pure copper sheets, then your electrolyte will stand a little longer before the coppergets more and more replaced by zinc and nickel.

Use a big 100-200ml syringe to clean up copper or silver that could float around every some hours.


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## jmdlcar

What was the Voltage used in this Cell? That the only thing I'm not sure of is it 5 or 12 volt?


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## jmdlcar

Do you know if Copper Sulfate 99% Pure Powder will work in the cell you did? 
And do you need to use copper as cathode if I use Copper Sulfate? 
I would like to use Stainless Steel non-magnetic for the cathode if it will work? 

Any help would be great. 

Jack


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## solar_plasma

Tap water cell is the best option in my eyes. CuSO4 has the problem of fouled electrolyte=a lot of actual waste solution.


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