Electrochemistry Copper Sulfate Electrolysis From Stock Pot Waste

[ARMCO]

I got my first bit of precious metals from stock pot. Picture is pure copper crystals electroplated onto pure copper bar. PM bead pic to follow later.

 

[ARMCO]

I got my first bit of precious metals from stock pot. Picture is pure copper crystals electroplated onto pure copper bar. PM bead pic to follow later.

Set up:




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[kjavanb123]

Looks good. What is the specifications on your rectifier?

Thanks
KJ

 

[nickvc]

It may pay you to not melt the values as the chances are very high it will need rerefining.

 

[ARMCO]

Looks good. What is the specifications on your rectifier?

Thanks
KJ

My DC power supply is fairly simple. I purchased it off eBay.

I have found that I get the best crystal growth if I control the voltage to keep it around 1.5volts. I’ll let the amps vary, but they are usually twice the voltage but that will vary from time to time.

The voltage may climb over time and I’ll have to adjust it back to 1.5v. I have found that the higher the voltage the quicker the copper deposits on the cathode but it’s not tight and hard. Rather it’s loosly attached and may fall off to the bottom when disturbed, which defeats the purpose.

 

[ARMCO]

It may pay you to not melt the values as the chances are very high it will need rerefining.

Hi, thanks for the comment. I’m not sure your meaning though. Let me clarify my process shown in the pictures.

The smelting is from the solids from my stock pot which are mostly copper by percentage, but contain many elements since some was obtained by using zinc. The rest comes from what was cemented out of the stock pot with copper; then copper cemented out in next pot by iron.

Now if I was good at this I’d have just precious metals from cementing with copper. I’d have only copper from cementing with iron. And I wouldn’t need to “nuke” everything with zincto make sure I got everything out of solution. But I’m not good at it yet. So I have predominantly copper with precious metals, and everything else lower than zinc on the reactivity table.

So I smelted those solids; then made my first attempt at electrolytically purifying the copper so I could have a reduced volume (the anode slimes) to refine.

If I had not smelted the solids the amount of nitric acid to dissolve all that copper (instead of electrolytically separating the bulk of it out) would be enormous.

So there isn’t a point in this process that I would eliminate the smelt, or that I’m doing an extra refining because of it. Im doing a wet refine with the anode slimes after the copper is electroplated out.

Happy for your comment. Don’t know if the above explanation clarified or perhaps I did not understand and would welcome your clarification.
Thanks.

 

[Shark]

I am a bit unsure what I am seeing in the pictures. Are you using half the poured bar as the anode and the other half as the cathode?

The plating looks very good, and solid.

 

[IdahoMole]

Thanks for posting. I set up my first cooper cell last week so I will be following with interest.

 

[nickvc]

Armco I was referring to your slimes from the cell, the chances are it will still be mainly copper with other elements including values so it will pay to keep them as powders, the first step I think would be to put the slimes in a beaker and add dilute sulphuric and heat, this should remove most of the copper and maybe several other unwanted elements. The whole idea is to reduce it all to as small a quantity as possible so recovering the values becomes much easier and in a more concentrated form.

 

[ARMCO]

Armco I was referring to your slimes from the cell, the chances are it will still be mainly copper with other elements including values so it will pay to keep them as powders, the first step I think would be to put the slimes in a beaker and add dilute sulphuric and heat, this should remove most of the copper and maybe several other unwanted elements. The whole idea is to reduce it all to as small a quantity as possible so recovering the values becomes much easier and in a more concentrated form.

Thanks for the clarification. I appreciate it.

No I did not smelt the anode slimes. I treated them with nitric acid to remove as much copper (you’re correct, plenty left) and then what was left after that was treat with AR and precipitated with Copperas. Twice. I ended up with s small bead that was still >%50 silver and about %44 gold.

I only did this with a small portion of the first bit of anode slimes that I got. That was a large slab anode I poured that I split into three pieces and so the process is still ongoing.

I would be interested in treating the slimes with sulfuric like you said instead of nitric before going to the aqua Regia so thanks for that suggestion.


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[g_axelsson]

Nice electrolytic copper.

An explanation of why the copper becomes loose if you use higher voltages is that at higher voltages you start splitting water into oxygen and hydrogen, the gas bubbles sits on the surface of the cathode and hinders copper to attach directly to the surface so it will form a weak moss of copper strings.

I'm running some experiments right now with a sulfate based cell and I have found that around 1V and above I create gas and mossy copper while at below 1V it forms a nice hard metal surface.

pH, temperature and concentration of metal ions as well as which metal ions that are present all affects the safe voltage.

Göran

 

[ARMCO]

I am a bit unsure what I am seeing in the pictures. Are you using half the poured bar as the anode and the other half as the cathode?

The plating looks very good, and solid.

Yes, happy to clarify.
The poured anode was split into 3 pieces to fit in the cell. Doing them one at a time essentially.

The cathode I used was a pure (commercial) copper bar. I could not find my small sheet of stainless I thought I had so I used a pure bar that was less than 1 lb (due to using it to cement some gold that stubbornly would not drop). It is well over 2 lbs now and all you see on it is very hard and fixed.

I’ll attach a picture of the bar when I first started. I didn’t take one until I had already started plating a little bit but you’ll get the “picture” so to speak. ;-)


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[Shark]

Thanks, the shape of your copper bar is what must have fooled me. Now I am wishing I had thought of that when I first started experimenting with mine,

 

[ARMCO]

Nice electrolytic copper. [emoji1]

An explanation of why the copper becomes loose if you use higher voltages is that at higher voltages you start splitting water into oxygen and hydrogen, the gas bubbles sits on the surface of the cathode and hinders copper to attach directly to the surface so it will form a weak moss of copper strings.

I'm running some experiments right now with a sulfate based cell and I have found that around 1V and above I create gas and mossy copper while at below 1V it forms a nice hard metal surface.

pH, temperature and concentration of metal ions as well as which metal ions that are present all affects the safe voltage.

Göran

Thank you.

1.5v Is working ok for me right now. Temp has been staying around 55F
I have not monitored pH and wouldn’t know how to measure or assess concentration of metal ions (specific gravity?)

And thanks for the explanation you gave. Really appreciate it.


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[ARMCO]

I got impatient and processed a small bit of the slimes before finishing the whole anode bar. (Less than 1/3). It’s was as noted above about %45 gold or so and a higher % silver.

 

[ARMCO]

I should say that I don’t consider that a very good job refining to be 44% gold 50+ percent silver. (Actually not refined yet I guess) But the bead was only a half a gram and I didn’t want to mess with it any further until I got the rest of the anode slimes by finishing the electrolysis. Then hopefully I’ll have added enough material and I’ll finish the refining process. [emoji846]



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[FrugalRefiner]

How can you have so much silver after refining with AR? Silver is only slightly soluble in strong AR. Diluting and cooling your AR once your metal is dissolved should eliminate the bit that can be in solution. Filter till your solution is crystal clear, then drop your gold. Silver should be negligible.

Dave

 

[ARMCO]

How can you have so much silver after refining with AR? Silver is only slightly soluble in strong AR. Diluting and cooling your AR once your metal is dissolved should eliminate the bit that can be in solution. Filter till your solution is crystal clear, then drop your gold. Silver should be negligible.

Dave

Lol. You are absolutely right Dave.

I normally do exactly as you state. I truly was impatient because this was the first bit of PMs from my waste that I’d actually dropped.

I’ve done fine with placer gold and karat gold (inquarting), foils (plain AR and SMB), but my “dirty” stuff I’ve fought with and so I got a little excited and left out exactly what you stated, didn’t make sure it was cold and filtered until crystal clear. [emoji20] (embarrassed)


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[ARMCO]

It continues to grow. We’re nearly done.




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[ARMCO]

Armco I was referring to your slimes from the cell, the chances are it will still be mainly copper with other elements including values so it will pay to keep them as powders, the first step I think would be to put the slimes in a beaker and add dilute sulphuric and heat, this should remove most of the copper and maybe several other unwanted elements. The whole idea is to reduce it all to as small a quantity as possible so recovering the values becomes much easier and in a more concentrated form.

Nickvc, how dilute? I am just about to work on the last anode slimes. (Last pic)

Final tally on electrolytic copper is over 3 lbs. I started with a pure copper bar that was less than a pound.

i


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