# Electrolyte for refining silver



## Tammyjefferywilliam (Feb 28, 2015)

If I want to operate a small silver cell just to try the process, and I dissolve exactly 1 ounce of silver with nitric acid and then dilute it 10 times over, exactly how much shot (cemented sterling) could I process before I would need new electrolyte?


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## FrugalRefiner (Feb 28, 2015)

Tammyjefferywilliam said:


> If I want to operate a small silver cell just to try the process, and I dissolve exactly 1 ounce of silver with nitric acid and then dilute it 10 times over, exactly how much shot (cemented sterling) could I process before I would need new electrolyte?


A lot.

I know that's a very general answer, and not very helpful, but there are several variables at play.

You didn't say what concentration of acid you're using. If it's concentrated acid, you'll have a difficult time dissolving the silver. We dilute concentrated acid with distilled water so there's enough water to hold the silver nitrate in solution.

So diluting it "10 times over" depends on how much volume you start with. You'd be better off dissolving a known amount of silver into a known final volume of electrolyte so you'll know how many grams of silver you have per liter of electrolyte.

We don't know how clean your cemented silver will be. 99%, 98%, maybe less. It depends on your technique.

As you operate the cell, the copper from your shot will displace silver from your electrolyte. Both the level of copper and the level of silver remaining in the electrolyte will affect when the copper starts to codeposit (as well as your voltage, current density, etc.)

Sorry I can't give you an exact answer.

Dave


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## Tammyjefferywilliam (Feb 28, 2015)

Forgive me for not being more specific. I was referring to dissolving the pure silver with 70% nitric and doing the same with the sterling (mixed with an equal volume of distiller water) and then cementing it onto copper. But I have another general question as well: how exactly do I know when the pure crystals in the cell become contaminated with copper? Forgive me again, I can't find an answer anywhere else.


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## FrugalRefiner (Feb 28, 2015)

Tammyjefferywilliam said:


> Forgive me for not being more specific. I was referring to dissolving the pure silver with 70% nitric and doing the same with the sterling (mixed with an equal volume of distiller water) and then cementing it onto copper. But I have another general question as well: how exactly do I know when the pure crystals in the cell become contaminated with copper? Forgive me again, I can't find an answer anywhere else.


If I understand you correctly, you're dissolving one ounce of silver for your electrolyte. You'll need about 30 ml. of nitric diluted with 30 ml. of water. If you dilute that by 10, you'll end up with one ounce of silver in 600 ml. of electrolyte. That's pretty low starting silver content. At that level, copper will contaminate your crystal pretty quickly. You might want to keep studying to see what others are using.

We still don't know how pure your cemented silver is. 

To test the purity of your crystal, dissolve a bit in 50/50 nitric acid. If it's pure, the solution should be virtually clear. If there's any blue tint, you've codeposited copper (or not washed your crystal enough).

It took me a year and a half to read through all the information on the forum the first time.

Dave


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## Tammyjefferywilliam (Feb 28, 2015)

The method I have been referring to is a video by kadriver submitted on YouTube in which he uses four batteries to run the cell and uses a 10% silver nitrate solution for the electrolyte. The shot made from cemented silver is supposed to be 98% pure.


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## FrugalRefiner (Feb 28, 2015)

Tammyjefferywilliam said:


> The method I have been referring to is a video by kadriver submitted on YouTube in which he uses four batteries to run the cell and uses a 10% silver nitrate solution for the electrolyte. The shot made from cemented silver is supposed to be 98% pure.


30 grams of silver in 600 ml. of electrolyte is not a 10% solution.

As I said above, whether _your_ cemented silver is 98% or not depends on _your_ technique.

Reading and watching videos will teach you the general principles. Only experience will teach you the fine points. With experience, you'll learn how much of _your_ silver cement _you_ can run through _your_ cell. I'm really not trying to be difficult, but trying to give you a specific answer is like trying to tell you how big a rock is, or how much a car costs.

Dave


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## Tammyjefferywilliam (Feb 28, 2015)

I've been researching and the closest thing I can come up with is that to get an acceptable level of silver for my electrolyte I have to start with a known volume and work in reverse, so If I want 1/2 liter of electrolyte, then I need about 8.5 oz. of 70% nitric and 8.5 oz. of distilled water with 1.5 troy ounces of pure silver dissolved in it. I couldn't find the recipe I've read others discussing, so is that close? And If my anode and shot are at least 98% pure and I run it at 3.3v in a thumb cell configuration, about how much could I expect before needing to change my electrolyte? If I ran a theoretical 6 Troy ounces of shot, that 2% of copper would completely displace the silver in the solution. There would be no silver to recover at the end. Will a cell operate to depletion that way, or is there some point that the copper will start contaminating the crystals?


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## kurtak (Mar 1, 2015)

Tammyjefferywilliam said:


> so If I want 1/2 liter of electrolyte, then I need about 8.5 oz. of 70% nitric and 8.5 oz. of distilled water with 1.5 troy ounces of pure silver dissolved in it. I couldn't find the recipe I've read others discussing, so is that close?



No :!: 

dissolving 1.5 ozt with 8.5 oz 70% nitric (& 8.5 oz D-water) will leave you with far to MUCH free nitric in your electrolyte which mean it will then actually work at dissolving your anode bar (or shot) thereby putting more silver (from your anode) into your electrolyte - instead of electrolytic "parting" your silver from anode to cathode

your electrolyte has to be absolutely saturated (pregnant) with silver (no free nitric left to dissolve more silver) to work properly

As a "general rule" you can figure that it takes 1.17 ml of 70% nitric & 1.17 ml of D-water to dissolve 1 gram silver resulting in a saturated solution (no more free nitric)

So to dissolve 1.5 ozt silver = 46.65 grams X 1.17 = 54.58 ml nitric + 54.58 ml D-water --- you then dilute that with enough D-water to make your 500 ml of electrolyte

However - conditions can change that - as an example - if you do it (dissolve your silver) in a "closed" reaction vessel (beaker on a hot plate with a watch glass on it) you will dissolve more silver with the same amount of acid (meaning 1.17 ml acid will dissolve more then 1gram Ag)

So what you want to do is start with your 1.5 ozt Ag add about 45 ml acid & about 60 - 65 ml D-water (extra water allows for evaporation &/or addition of more acid - if need be) let that react (on a hot plate) until the reaction stops - if there is still un-dissolved Ag - add a little more acid - once the starting Ag is all dissolved - add a little more Ag to insure any free nitric is used up --- then dilute this pregnant solution to your 500 ml for your cell electrolyte

As far as when your electrolyte becomes corrupted to the point that it starts co-depositing copper (or other metals) its hard to say because you don't know "for a fact" the purity of the silver (anode) going in --- this is going to be a learning curve on your part by running the cell - then testing the finished silver - to determine the what & how in the running of "your" cell

Kurt


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## Tammyjefferywilliam (Mar 1, 2015)

Thank you very much!


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## Harold_V (Mar 2, 2015)

kurtak said:


> As far as when your electrolyte becomes corrupted to the point that it starts co-depositing copper (or other metals) its hard to say because you don't know "for a fact" the purity of the silver (anode) going in --- this is going to be a learning curve on your part by running the cell - then testing the finished silver - to determine the what & how in the running of "your" cell
> 
> Kurt


And---what you learn from one anode (or batch of shot) may or may not be representative of the following anode or batch. It's all reliant on the amount of contamination forwarded with the recovered silver. Part nothing but pure silver and the lifespan is endless. Part contaminated silver and it may not get through the first attempt. No one can predict how much electrolyte will yield, as they have no way of knowing the purity of the anode. 

For what it's worth, here's some of my thoughts. 

My experience indicated that when my cell started growing long hairy deposits of silver (much like steel wool), it quickly started co-depositing copper. I would use the last silver recovered for making the electrolyte for the succeeding session. If it came out discolored (a hint of green), that was a sign of co-deposition. It was then tested to determine if the contamination was palladium or copper. 

Silver nitrate solution that has not been heated to a slow boil will often contain traces of nitrous oxide. That, in and of itself will give the solution a tint towards green. That was a common occurrence for me when I made electrolyte. I expect it does no harm, but it masks the true color of the electrolyte, which, for me, was the only method at hand for proving the purity of the silver I was refining. 

For my electrolyte, I dissolved 30 troy ounces of silver crystal in a liter of 68% nitric, diluted with a liter of distilled water. The resulting solution would readily crystalize upon cooling, so it was further diluted with water when the silver was fully dissolved. The silver nitrate solution was diluted to about 2½ gallons when introduced to the cell. With this amount of electrolyte I could part an anode of roughly 175 troy ounces. Each anode was different, so the yield from batch to batch varied, as some were contaminated heavily with palladium. All contained some copper. Palladium will co-deposit, just as copper does, assuming it's concentrated high enough in the anode. While I did no study of the problem, I am of the opinion that palladium co-deposits because it creates isolation at the anode, to the point where silver can no longer be transferred. At that point, palladium is. So long as the slimes aren't hard enough to require scraping to be removed, that shouldn't be a problem. I suffered that problem only once, and had to re-refine a couple hundred ounces. 

I brought my electrolyte to a boil (covered with a watch glass) after dissolution. I learned, from repetitively making the electrolyte, that I consumed all of the nitric by doing so. It was common for a few bits of silver to remain, undissolved, verifying that all nitric had been consumed. When the electrolyte was introduced to the cell, I added several drops of nitric acid. By doing so, I ensured that the pH was 1, or slightly lower. 

Harold


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## kurtak (Mar 2, 2015)

Harold_V said:


> And---what you learn from one anode (or batch of shot) may or may not be representative of the following anode or batch. It's all reliant on the amount of contamination forwarded with the recovered silver. Part nothing but pure silver and the lifespan is endless. Part contaminated silver and it may not get through the first attempt. No one can predict how much electrolyte will yield, as they have no way of knowing the purity of the anode.
> 
> My experience indicated that when my cell started growing long hairy deposits of silver (much like steel wool), it quickly started co-depositing copper. I would use the last silver recovered for making the electrolyte for the succeeding session. If it came out discolored (a hint of green), that was a sign of co-deposition. It was then tested to determine if the contamination was palladium or copper.
> 
> Harold



Correct - this is what I meant when I said - this is going to be a learning curve on your part by running the cell - then testing the finished silver - to determine the what & how in the running of "your" cell

I also keep an eye on the depth of the color of the electrolyte - from a light blue to a "deeper" darker blue (or green if palladium is present) after you have run the cell a few times the depth of the color of the electrolyte is "somewhat" of an indicator to then start watching the crystal growth --- the reason you start getting a finer (hair like) crystal growth is because the silver concentration of the starting electrolyte is being displaced by the copper (&/or palladium) & thereby becoming more & more of a copper electrolyte & thereby depositing less silver - which then indicates that it is nearing the point of starting to deposit copper (&/or palladium if present)

Kurt


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## kadriver (Mar 3, 2015)

Tammyjefferywilliam said:


> The method I have been referring to is a video by kadriver submitted on YouTube in which he uses four batteries to run the cell and uses a 10% silver nitrate solution for the electrolyte. The shot made from cemented silver is supposed to be 98% pure.




Hello, I think you've got the wrong fellow here. I have never made a video using batteries as a power source for a silver cell. I have produced a video in two parts that shows how to make silver shot for the cell and how to build a 3.5 liter small scale silver cell using a stainless steel bowl. I have always used a DC power supply to run my silver cell(s).

I think I responded to a message from you about electrolyte on my YouTube channel.

When making electrolyte I NEVER use a set amount of nitric acid. I place the pure silver crystal in a suitable beaker WITH A WATCH GLASS OR SAUCER TO COVER THE BEAKER and add DISTILLED water only.The only time the cover is off the beaker is when I am adding reagents or more distilled water. I like to use a little over 150 grams of pure silver crystal per liter of electrolyte.

Then over the course of a 24 hour period or so with medium low heat I slowly add small doses of concentrated nitric acid until Maybe 10% of the silver is left undissolved. Then I turn up the heat and lightly boil the solution adding concentrated nitric acid in decreasing doses until just a few bits of silver are left and absolutely no more fumes are produced.

As pointed out earlier, this ensures that very little free nitric acid is in the electrolyte which is a good thing because excess free nitric acid causes problems. Under no conditions would I ever use electrolyte that contained 50% concentrated nitric acid.

Also, the amount of silver in your electrolyte will affect conductivity between your anode basket (positive power lead) and the cathode (negative power lead). Higher silver concentration in your electrolyte will make it more conductive and increase electrical flow (amperage) which will increase the speed that the cell dissolves the silver in the anode basket and plates out the pure silver at the cathode. Another factor is the anode basket size. A larger basket and filter will present more surface area of impure silver to the cell and dissolve the impure silver faster.

Good luck with your silver cell experiments!

kadriver aka sreetips


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## Tammyjefferywilliam (Mar 9, 2015)

I thank everyone for their input. I have a good idea of how to begin the process now. But I have just one more question. I have heard that 3% hydrogen peroxide used with nitric makes for less fumes when dissolving silver. could that be used in the beginning stages and then diluted with distilled water to form the electrolyte? If it dissolves silver at a different rate, or displaces it poorly from the solution, or contaminates with copper easily, then I understand it would be a poor choice. Just curious.


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## butcher (Mar 9, 2015)

3% peroxide can help to keep fumes of the reaction from escaping so much, keeping them in solution (with water to reform nitric acid), as the H2O2 adds oxygen to the solution which can help to convert nitrous oxide gas in solution to Nitrogen dioxide gas which is water soluble. the diluted solution helps to keep these gases in solution to reform HNO3 to react with metal instead of escape as gas.

3% H2O2 is mostly water, this dilutes the nitric acid, so you need to take this extra water into consideration.

Nitric acid or silver nitrate solution can be concentrated by evaporation, (nitric acid azeotropes at 68%), silver nitrate can be evaporated till it begins to form silver nitrate crystals.

You could use the 3% H2O2 for the amount of water you would normally add to the reaction, this way your not adding a lot of extra water that you may need to evaporate later.


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## g_axelsson (Mar 9, 2015)

Haven't done it myself, but the hydrogen peroxide adds oxygen to the nitric oxides (aka bfrc, or big freaky red cloud) so the gas can be reabsorbed in the water and create more nitric acid. It makes the nitric last for longer and keeps down the amount of NOx given off.

Exactly what it will do when dissolving silver I don't know. Silver is catalyzing hydrogen peroxide into water, oxygen and a lot of heat. Strong hydrogen peroxide and silver makes up the reactive part of some rocket engines.
If testing this, do it at a small scale and only with weak hydrogen peroxide, not strong because somewhere at unknown concentrations and temperature is the point where your silver electrolyte turns into an explosion, throwing acid and silver nitrate all around.

The safest option and what I recommend strongly is to never mix silver metal with hydrogen peroxide.

Göran


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## FrugalRefiner (Mar 9, 2015)

You can also keep most of the NOx in your beaker during digestion by simply covering the beaker with a watch glass. A bit will still escape, but much of it will go back into your solution naturally.

Dave


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## kurtak (Mar 11, 2015)

FrugalRefiner said:


> You can also keep most of the NOx in your beaker during digestion by simply covering the beaker with a watch glass. A bit will still escape, but much of it will go back into your solution naturally.
> 
> Dave



Which in turn will allow you to dissolve more silver with less acid

Kurt


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## Tammyjefferywilliam (Mar 13, 2015)

I have one more crazy question. Suppose I'm Inquarting some gold with sterling and now I'm doing a nitric acid wash to remove the silver and base metals. Suppose I did 2 additions of nitric acid and now I've run out. Is it possible to use a nitrate salt instead? I have seen poor man's Aqua Regia made this way.


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## Barren Realms 007 (Mar 13, 2015)

Tammyjefferywilliam said:


> I have one more crazy question. Suppose I'm Inquarting some gold with sterling and now I'm doing a nitric acid wash to remove the silver and base metals. Suppose I did 2 additions of nitric acid and now I've run out. Is it possible to use a nitrate salt instead? I have seen poor man's Aqua Regia made this way.



It is not a wise decision to use a nitrate salt for working with silver. Either to make your own nitric or to use the nitric cold recipe. You are liable to run into chlorides using nitrate prill's in this fashion and this will develop a passivation layer of silver chloride on your inquarted gold and more than likely to continue your process you will need to remelt your shot to continue your process of removing the silver and other base metals.


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## g_axelsson (Mar 13, 2015)

Barren Realms 007 said:


> Tammyjefferywilliam said:
> 
> 
> > I have one more crazy question. Suppose I'm Inquarting some gold with sterling and now I'm doing a nitric acid wash to remove the silver and base metals. Suppose I did 2 additions of nitric acid and now I've run out. Is it possible to use a nitrate salt instead? I have seen poor man's Aqua Regia made this way.
> ...


Any chlorides in the resulting nitric acid made from nitrates and sulfuric acid can easily be dropped by adding a few drops of silver nitrate to the nitric acid until no more precipitate is formed. All chlorine ions are swept up by forming silver chloride that easily settles on the bottom. The silver nitrate will also combine with any sulfate, precipitating silver sulfate.

When additional silver nitrate doesn't produce any more precipitate the home made nitric acid is as clean as it can be and should be good enough to be used for parting gold and silver.

This way of cleaning up home made nitric could produce quite a lot silver sulfate that has to be taken care of in a later step, therefore it is always better to use pure nitric acid from the beginning.

Göran


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## solar_plasma (Mar 14, 2015)

As a side note: AgSO4 is too soluble to drop quantitatively, If absolutely needed SO4++ can be precipitated almost quantitatively by adding only the needed amount of Ba(NO3)2. This will leave you with insoluble BaSO4 and HNO3.


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## Wulfgar (Aug 27, 2022)

kadriver said:


> Hello, I think you've got the wrong fellow here. I have never made a video using batteries as a power source for a silver cell. I have produced a video in two parts that shows how to make silver shot for the cell and how to build a 3.5 liter small scale silver cell using a stainless steel bowl. I have always used a DC power supply to run my silver cell(s).
> 
> I think I responded to a message from you about electrolyte on my YouTube channel.
> 
> ...


Holy crap,
It’s streetips! I love your videos man. I’m about to start doing this myself, along with the gold refining ones. I follow all your videos. Will this method work for gold as well? Meaning, can I use chloroauric acid as an electrolyte?


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