# precious metal recovery method



## Tahmoures (Jan 30, 2022)

hello to all
im new to metal recovery business and im working about two months on small batches for gold recovery.
the method im using is Aqua regia and it works well for me.
i dissolve base metals in nitric acid and filter gold plated parts that seperates from board surface and after cleaning i dissolve gold in AR and after that the other processes will be done.

im intrested in copper and silver recovery too, I know about silver that i can percipitate silver in AgCl form when i add HCl in my nitric acid solution after gold filtering,
and for copper i know about adding sulfuric acid in hno3 solution for cuso4.5h2o percipitating. im intrested in CuSO4.5H2O pure form because im my country its more expensive than. pure copper form.

but i think these prosedures that i wrote is not that much easy that im thinking because of other base metald.

will you help me how to do this silver and copper separation and how to recover them?

best regards
tahmoures (or you can also say "tahi")


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## nickvc (Jan 30, 2022)

Welcome to the forum.
To recover your copper you could cement your solutions with iron or steel, this will not be pure copper so to get that you need to set up a copper cell and feed the recovered copper into the cell, the electrolytic refining of copper is the oldest electrolytic process and is covered in detail no doubt in many languages on the internet so you should be able to make that possible, from there you have pure copper if you run your cell properly and then you can make whatever you want , the reason the price is higher for the product you want is the processing costs are higher .


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## Tahmoures (Jan 30, 2022)

Tahmoures said:


> hello to all
> im new to metal recovery business and im working about two months on small batches for gold recovery.
> the method im using is Aqua regia and it works well for me.
> i dissolve base metals in nitric acid and filter gold plated parts that seperates from board surface and after cleaning i dissolve gold in AR and after that the other processes will be done.
> ...



one part is missing
i work on weee like telecom board scraps or cpus or rams and etc.


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## Tahmoures (Jan 30, 2022)

nickvc said:


> Welcome to the forum.
> To recover your copper you could cement your solutions with iron or steel, this will not be pure copper so to get that you need to set up a copper cell and feed the recovered copper into the cell, the electrolytic refining of copper is the oldest electrolytic process and is covered in detail no doubt in many languages on the internet so you should be able to make that possible, from there you have pure copper if you run your cell properly and then you can make whatever you want , the reason the price is higher for the product you want is the processing costs are higher .


dear nickvc
thank you so much for your answer.
i think for lower cost i can raise the scale and use more electrodes, but how about the time spending for this refining method?
is this the best method for copper refining at the terms of cost and time spending on this method?


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## nickvc (Jan 30, 2022)

You are welcome to my view.
With all electrolytic processes you are limited by the amount of power you can apply so you recover fine metals and yes it’s by far the cheapest method, you may well recover other values from the slimes which will help offset any costs. 
You need to research copper cells as I said the full details of successful operation is fully documented as it’s such an old technology.


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## Tahmoures (Jan 30, 2022)

nickvc said:


> You are welcome to my view.
> With all electrolytic processes you are limited by the amount of power you can apply so you recover fine metals and yes it’s by far the cheapest method, you may well recover other values from the slimes which will help offset any costs.
> You need to research copper cells as I said the full details of successful operation is fully documented as it’s such an old technology.


so as a result, I'll study about electrowinning method for copper recovery

thank you so much for your help.


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## Martijn (Jan 30, 2022)

As i understand, you prefer to get copper sulfate. 
You can convert the copper nitrate to copper sulfate with H2SO4 and distill off the nitric acid for reuse. 
If you evaporate the copper sulfate solution down until other base metals are pushed out as sulfates, decant hot and let it cool, CuSO4 crystals will formed to be collected. 
I just made a post about it in tutorials. 

To get silver out of solution, cementing on copper may be a better option for you in stead of the AgCl route. 
You collect the cemented silver and just melt it after washing. Further refining can be done with a silver nitrate cell. 

Martijn.


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## Tahmoures (Jan 31, 2022)

Martijn said:


> As i understand, you prefer to get copper sulfate.
> You can convert the copper nitrate to copper sulfate with H2SO4 and distill off the nitric acid for reuse.
> If you evaporate the copper sulfate solution down until other base metals are pushed out as sulfates, decant hot and let it cool, CuSO4 crystals will formed to be collected.
> I just made a post about it in tutorials.
> ...


Dear martjin
Thank you so much for your answer and advice
I'll check your post about copper sulfate

About silver refining, is cementation and after that melting purify silver or there are some other metals present in the final product?

Tahmoures


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## Martijn (Jan 31, 2022)

The first silver comes out the purest. The last bit is less pure and contains more copper. I think its from tiny pieces of copper flaking off at the end by irregular corrosion. 

Keep the copper fully submerged in the solution and stop when cementing slows down, or the color of the cement darkens, decant and cement out the last bit separately. Save that for inquarting gold when needed. 

Wash the silver with hot distilled water (many times with a little bit of water is better than a few times with a lot of water) and test for silver nitrate with a drop of HCL in a bit of the wash water. (White cloudy AgCl) Put all wash water with silver traces in the silver stockpot. 
Save the bit of silver chloride separately. Put it in the sun and watch it turn purple for fun. 

Then wash and test for copper traces in the wash water with ammonia.(light blue color) You can end up with pretty pure silver. 

Make sure your copper is solid enough. Thin copper can flake off the edges leaving tiny copper pieces in the silver. Use the used up copper pieces for cementing the last bits out or use them in the stockpot. 

If your source material did not contain any Pd, the only thing after a nittic bath cementing out should be pure silver. As far as i know...

Martijn.


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## Martijn (Jan 31, 2022)

And something important about the copper nitrate to sulfate conversion: dont use too much sulfuric acid. From about 65 grams of copper and 100 grams of H2SO4 you make 165 grams of copper sulfate. 
Evaporate and decant warm in stead of hot. 60 degrees C is fine. If there is too much sulfuric it can get dangerous when hot. 
Always handle chemicals with the proper safety gear. Especially when warm.


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## Tahmoures (Feb 1, 2022)

Martijn said:


> The first silver comes out the purest. The last bit is less pure and contains more copper. I think its from tiny pieces of copper flaking off at the end by irregular corrosion.
> 
> Keep the copper fully submerged in the solution and stop when cementing slows down, or the color of the cement darkens, decant and cement out the last bit separately. Save that for inquarting gold when needed.
> 
> ...


thank you so much.
I'll try this out as soon as possible.
and thanks about cation qualitative identification tests, that will help me so much


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## Tahmoures (Feb 1, 2022)

Martijn said:


> And something important about the copper nitrate to sulfate conversion: dont use too much sulfuric acid. From about 65 grams of copper and 100 grams of H2SO4 you make 165 grams of copper sulfate.
> Evaporate and decant warm in stead of hot. 60 degrees C is fine. If there is too much sulfuric it can get dangerous when hot.
> Always handle chemicals with the proper safety gear. Especially when warm.


exactly.
safety first


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## nickvc (Feb 1, 2022)

Martijn said:


> The first silver comes out the purest. The last bit is less pure and contains more copper. I think its from tiny pieces of copper flaking off at the end by irregular corrosion.
> 
> Keep the copper fully submerged in the solution and stop when cementing slows down, or the color of the cement darkens, decant and cement out the last bit separately. Save that for inquarting gold when needed.
> 
> ...


If you have enough percentage of silver any platinum will also cement along with the palladium, I’m not sure if they are the last to do so or if they cement with the silver.


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## GoIdman (Apr 9, 2022)

Maybe a bit off topic, but this is why youtube recovery can literally kill you....

Just came across this video...

 

Decide for yourself..

Safety..safety...safety...

Be safe

Pete


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## justinhcase (Apr 9, 2022)

GoIdman said:


> Maybe a bit off topic, but this is why youtube recovery can literally kill you....
> 
> Just came across this video...
> 
> ...



This reminds me of an old refining joke.
"What do Bill Clinton and a refiner have in common?"
No?
" Neither of them ever inhale."


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