# copper anode slime



## coksakin (Nov 19, 2008)

hi everybody.. i have read most of the topics in forum for 2 years but this is my first message..

i love recycling, especially precious metal winning. also i work in electrolithic copper plant. we produce lots of anode slimes every month that include ~2 kg/ton Au and ~4.5 kg/ton Ag , %25-40 Cu (Pb,Sn sulphates) Te,Se most of copper silver and gold in telluride and sellenide form.

Have anybody ever worked with copper anode slimes before?


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## Shecker (Nov 19, 2008)

On a small scale yes I have. But certainly not on the scale you've indicated.
If you use copper sulfate, sulfuric acid as the electrolyte the anode slims with be black (or perhaps dark brown if the gold content is high enough). Once I tried using copper chloride/HCl as an electrolyte and found that it also worked really well except for one problem. The silver came out of the anode as silver chloride, turned the entire electrolytic bath white (and then black from the photosensitivity of silver chloride) and stuck to everything. Every now and then I had to take the anodes out and scrap them down because of the build up of silver chloride. I believe copper sulfate/sulfuric acid is a better electrolyte for copper refining. Just a thought.

Randy in Gunnison in the USA


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## OMG (Nov 19, 2008)

I haven't yet but I want to set up a small scale 'copper' cell and collect the anode slimes and process them.
You say 25% - 40% of the anode slime is copper sulfides?
and is that with lead and tin only?


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## Harold_V (Nov 20, 2008)

coksakin said:


> Have anybody ever worked with copper anode slimes before?


Yes, one encounter, from one of the largest copper producers in the US. The sample was small, the results of a small amount picked up doing a repair in the facility by a friend. It contained selenium, along with other contaminants, and resembled the typical slimes, being black in color. 

I roasted the slimes to redness, dissolved in dilute nitric to eliminate base metals and silver, then processed the remains with AR. No big deal, assuming you don't have a large amount to process. 

Note that I did the roasting in a fume hood, to avoid the toxic fumes. Handle with care!

Harold


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## Oz (Nov 20, 2008)

OMG,

What is your source of copper that you expect PMs in your slimes?


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## Harold_V (Nov 20, 2008)

Oz said:


> OMG,
> 
> What is your source of copper that you expect PMs in your slimes?


To my knowledge, it's commonplace for copper slimes to contain a huge array of precious metals. They accompany the copper ore, and can be relatively sparse, or even a major contributor to the production. That is the case with Kennecott. 

Kennecott Copper Corp., the one from which the sample came that I refined those many years ago, produces silver, gold, copper, platinum, palladium, and many of the other base metals in various quantities, all from the slimes from the copper refinery. 

Harold


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## Oz (Nov 20, 2008)

I would readily agree that if it is copper ore PMs are almost surely present. A similar example of this would be that 60% of global silver production is a byproduct of base metal refining. This is also a heads-up for any silver bugs out there. Base metal mines are shutting down faster than others due to low commodity prices (look what scrap is bringing now) and is sure to impact silver supplies.


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## coksakin (Nov 20, 2008)

source come from CuFeS2 mineral most of the copper production come from it and also it includes lots of pm.

in slime lead and tin in sulfide form but cannot dissolve in H2SO4 copper and other elements are in metalic form and because of the telluride and sellenides its not possible to eleminate the copper with nitric acid.


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## OMG (Nov 20, 2008)

Oz, I put a quote around copper in my post because it will just be a cell the same as a copper cell is set up. But, there will be copper and it will mostly come from chalcopyrite (CuFeS2) from placer concentrates. The 'copper' cell will be used to dissolve and win out most of the base metals.

coksakin, that lead and tin you speak of: Does it stay in sulfide form or in sulfate form? I was thinking of bubbling ozone in the cell to help oxidize all of the sulfides into sulfates. I would think that would make the tin dissolve. Do you know how they extract the values from the slimes when they are in selenides and tellurides?


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## Oz (Nov 21, 2008)

Thank you for the clarification.


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## coksakin (Nov 21, 2008)

SnSO4 and PbSO4 form. they eleminate most of the copper by heating 100g/l H2SO4 to boiling temp. and after eleminate tellur and after sellenium but i dont know how can they do it..


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## Zukun (May 26, 2020)

Hi, everyone on Goldrefiningforum.

I am looking for anode slime with rich Au, Ag and other non-ferrous metals.

Any company has anode slime in hand and about to sell it out, please PM me here, thx.


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