What is this stuff?

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Zhazham

Well-known member
Joined
May 11, 2021
Messages
47
Location
Finland
Hi,

I'm new to refining metals and just had my first harvest for my silver cell. It was working ok. I was able to get good conductivity, growth and all.

When i was harvesting silver, i noticed some strange color under the nice white silver chrystals. See attached picture. I saw same colour on top of some of the silver granules, what i was feeding to the cell.

Could it be gold? Silver was from gold plated items and possibly there were one white gold item too.

At first, i was using quite high voltage for the cell, as my basket filter was not so conductive. I changed to a lighter filter and was able to run cell with 3V and 1,5A.

I'm not happy with the result and have doubts of what to do with this stuff.
 

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After having a nap, i came to a conclusion that i might have had short circuit..at one point voltage started dropping and crystals were growin close to anode basket. I thought i noticed it early enough but after this result, maybe not.
 
You really have to get all silver separated/recovered before you start the cell. And your electrolyte needs to be from as pure silver as possible. In the beginning there will be a little contamination from left over copper from cementation. After the 1st good harvest you'll have very pure crystal for future electrolytes. Start over with distilled water and HCl to get your silver in solution and separated from the other metals. Hopefully the only contaminant will be copper. Most of that will be separated during cementation. Then your next run of the cell should come out a lot better.
 
I make my electrolyte from sterling. Some copper in the electrolyte helps keep any lead from going into solution and gives you denser crystal growth.

I don't understand the part about using "distilled water and HCl to get your silver in solution and separated from the other metals." Silver isn't soluble in HCl.

Dave
 
I agree with Dave I always used sterling dissolved in nitric for my electrolyte and cemented silver to refine.
Electrorefining requires high grade feed stock.
 
Both, electrolyte and silver shots, were of cemented silver. First dissolved in nitric, filtered and cemented with copper. Maybe i need to pay more attention for rinsing.

It is good to know that Sterling silver is good enough for electrolyte! Save a lot of time and acid. Mostly i have 813-830 silver from old jeweleries and medals but have some sterling too.

It is actually quite interesting how much old silver jewelery can contain gold. I already dropped 3g of gold, even i still have 2/3 of foils and solids not processed. This far i have processed about 1 kg of 813-830 silver.
 
And about the original problem. I decided to process it again, to get rid of color. This far it is looking much better.
 
With the forum changes, I'm not sure if I can find it again, but there was an excellent set of posts on how much copper your silver cell electrolyte could handle before it will begin plating out and contaminating your silver crystal.

I recall that by using sterling that had been put through nitric once, cemented with copper, along with some good rinsing that it could handle crystalizing at least five times as much silver before having to replace the electrolyte, rather than just starting with sterling.

I'll see if I can find it again and post it. Since implementing that technique, I've been able to run my silver cell for longer periods of time at the cost of using twice as much nitric to make electrolyte. (This is the technique I use to make anode bars as well, so I just take a few 100g bars and dissolve them to make electrolyte, the rest become anodes). Just my thoughts on technique here.

I've thought of using my silver crystal to make electrolyte, but it's just not worth putting it back into the refining cycle after being purified. I pour the bars and toss them in a box for my daughter's college fund. (Although lately, I think I might just store the crystal, I have a hell of a time pouring nice silver bars due to oxygen absorption.)

Elemental
 
Once your cell is running you can keep the electrolyte usable by adding fresh nitric to it and allow some of the fine silver to dissolve thus keeping the silver content high enough to produce good results , it’s a balancing act but the upside is you only have one solution to cement once you finish running , I used the electrolyte color as the signal it needed more nitric adding.
I was using the cell to recover gold and PGMs from mainly gold plated silver jewelry melted into bars.
 
What i have been reading from this forum, i thought copper is not a problem, as long as cell voltage is around 3V. Is it still possible to contaminate silver with copper, if electrolyte contains too much copper? Should there be change in conductivity or is the color only indication of polluted electrolyte?

About casting bars. Yesterday i sold one old gold coin and was talking about silver with the buyer. He was thinking that the crystals would be more interesting than bars. With chrystals, you can see whole content, with bars you won't.
 
Both voltage and copper concentration in the electrolyte play a part in whether copper will co-deposit. Even with a low copper concentration, if you run the voltage too high copper can co-deposit. But once the copper concentration reaches a certain level, even keeping the voltage low will not prevent it. I shoot for about 3 volts, and try to keep my copper concentration below about 50 grams per liter. I use color as the indicator. I made up a series of samples of copper in solution from 10 grams per liter up to 100. I compare the colors to the electrolyte color, and when it reaches about the 50 g/l level, I start replacing part of it.

Dave
 
I quess ability to monitor copper content by color, comes by experience.
 

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With the forum changes, I'm not sure if I can find it again, but there was an excellent set of posts on how much copper your silver cell electrolyte could handle before it will begin plating out and contaminating your silver crystal.

I recall that by using sterling that had been put through nitric once, cemented with copper, along with some good rinsing that it could handle crystalizing at least five times as much silver before having to replace the electrolyte, rather than just starting with sterling.

I'll see if I can find it again and post it. Since implementing that technique, I've been able to run my silver cell for longer periods of time at the cost of using twice as much nitric to make electrolyte. (This is the technique I use to make anode bars as well, so I just take a few 100g bars and dissolve them to make electrolyte, the rest become anodes). Just my thoughts on technique here.

I've thought of using my silver crystal to make electrolyte, but it's just not worth putting it back into the refining cycle after being purified. I pour the bars and toss them in a box for my daughter's college fund. (Although lately, I think I might just store the crystal, I have a hell of a time pouring nice silver bars due to oxygen absorption.)

Elemental
Using the purist possible silver in your electrolyte solution has a couple of benefits. 1 is that there's no copper in the starting solution so it lasts longer and is fairly easy to refresh (once) by simply adding a little more distilled water and/or electrolyte to the cell. 2nd is that your cell harvests will yield more silver of higher purity. And, depending upon the size of your cell, however much crystal you use for your electrolyte, none of it is ever lost. You always get it back and it just becomes a part of a cycle that is continually producing those improved yields. I lean toward not melting and pouring until there's a need or reason to spend the time and resources. A lot of people prefer the silver in crystal form once they see it.
 
Both, electrolyte and silver shots, were of cemented silver. First dissolved in nitric, filtered and cemented with copper. Maybe i need to pay more attention for rinsing.

It is good to know that Sterling silver is good enough for electrolyte! Save a lot of time and acid. Mostly i have 813-830 silver from old jeweleries and medals but have some sterling too.

It is actually quite interesting how much old silver jewelery can contain gold. I already dropped 3g of gold, even i still have 2/3 of foils and solids not processed. This far i have processed about 1 kg of 813-830 silver.
Where are you based that most of the salvaged silver you have is 813-830? Here in the USA we get almost all 925 sterling and 900 (Mexican and coin silver).
 
I'm from Finland. 813 and 830 are quite typical here for 1950-1970 jewelery. I don't know for sure but i quess it might have something to do with war reparations to the Soviet Union and being poor country.
 
I wish I could refine all <850 silver - as you said, there is a surprising amount of gold in it. I have a theory that where the silver is <925 (Russia, Middle East, South & Central America) it is due to historically cheaper labor costs, so there was less focus was on refining as the profit margin was greater on the sale of the final product. Contrast that to the US and UK where there
 
I wish I could refine all <850 silver - as you said, there is a surprising amount of gold in it. I have a theory that where the silver is <925 (Russia, Middle East, South & Central America) it is due to historically cheaper labor costs, so there was less focus was on refining as the profit margin was greater on the sale of the final product. Contrast that to the US and UK where there
is a long history of fine silversmithing, fine silver is re-alloyed with copper to have a much more consistent metal to work with.
 
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