Copper recovery through Electroplating

[Declan O'Reilly]

I need some advice on recovering copper from metal turnings using electroplating. We are trying to recover copper from turnings that vary, but have a content of between 48-50% Cu. The other impurities and their respective contents are as follows. Mn (24 %), Ni (13%) Zn (7%) W (3%) and Fe (2.7%). Is it feasible to try and plate out the copper from turnings with so many impurities? Is their a way to remove some of these impurities prior to plating?

We have an electroplating machine with stainless steel plates as the cathode and titanium baskets with the turnings inside as the anode . We are using an electrolyte solution comprised of Copper Sulfate and Sulfuric Acid. We have been running the machine for a couple months now, once or twice a week. So far most of our trials resulted in soft coarse deposits from high current densities or very thin plating to the point where you could wipe it off from the cathode plates.

We have achieved plating 3 times on these occasions only one side of one plate produced a quality deposit we could strip off. Strangely the outermost plates that are facing away from the anode baskets yield the best results. Any advice on how to achieve consistent repeated plating on all would be greatly appreciated.

Our aim is to find an economical way of extracting copper from the turnings and refining it to high grade copper, we wish to scale up our processes once we perfect the process.
If any one has ideas an an alternative way to do this I would love to hear it.

We are thinking of potentially smelting the soft copper we have recovered from the plates and from the sludge in the machine but it is not preferred.

 

[nickvc]

In honesty you are going to struggle with this due to the low copper content as all electro refining requires 95%+ of the desired metal in the feed stock, to be fair of you have large volumes you may do better to melt assay and ship onto a large copper refiner.

 

[Declan O'Reilly]

Interesting, thank you for your honesty. The sludge and brittle copper were getting is roughly 97% copper, maybe plating that would work.

Would it be possible to leach out the copper using Sulfuric Acid to get copper sulfate?

 

[nickvc]

Copper does not react much to sulphuric but it might well dissolve some of the other metals leaving a concentrated copper to run in your cell do some research and try some small scale experiments, I think you should also have the nickel intact which has significant value .

 

[speed]

Anything is possible but I dont think the electroplating or dissolution methods you suggest would ever be economical.

I would think smelting would be the best way to go but even doing that you wont beat a large scale copper refiner.

 

[Declan O'Reilly]

We already have a constant weekly supply of turnings and we are trying to get these back in to raw materials.

Our goal as a company isn't to beat large scale refineries, were just trying to convert waste streams back in to raw materials for reuse.

Thank you for your advice on smelting.

 

[Elemental]

Instead of looking at electro-refining, perhaps you should search for electrowinning. I'm not sure if it will meet your needs with the other metals you have in your stock.

 

[Declan O'Reilly]

Thank you I will check out that book!

 

[Elemental]

Here's another book regarding electro-chemistry from the Harvard Library.

The Electro-plating and Electro-refining of Metals by: Alexander Watt (Re-write by Arnold Philip) Year: 1902

https://archive.org/details/electroplatinga00wattgoog

 

[Declan O'Reilly]

Thank you, I really appreciate the resources!

 

[AustAuScrap]

Hi,
A first post from sort off the middle of no-where in Australia, So Greetings, and thanks for the posted link to the Books above. I have finally got to retirement and am ready to starting to learn again like every (born again) teenager should.
Unlike others I don't expect Hi Value Consulting work for nothing, but hope a little pointing in right direction and or guidance if on the Wrong Track would be available and appreciated.
My life has for medical reasons taken a new turn where metal detecting/coin scratching is no longer viable, so I have started dabbling with what a few others have called Micro-scrapping, that is pulling other peoples junk down to every last screw and bit of plastic.
As I exist on the edge of one of our plentiful deserts here near the center of Australia I have access to a lot of cheap to moderately priced PV electricity during sunlight hours.
Are there any other sources to study and learn from, as well as above links that any of you would like to direct me to that could be useful for me to maximize the value of the scrap copper, brass , aluminum/copper mix?
At this stage I am turning copper smalls (wire off cuts, nuts/screws etc) into larger cast bits in a melt furnace using old sump oil as a fire source.
My thought keep returning to some source of electro plate or electro winning process - powered by my PV DC power. The main cause of these recurring thoughts are the big copper mine down the road a bit, BHP's Olympic Dam. It uses electro-winning as one of their production methods as well as Electro-Refining big cast copper ingots that are made thru a more conventional Smelt and cast process..
I understand the Electro Winning process they use is thru some company from Finland. I don't want secret info from someones process, but would there not be some sort of Chemical, physics based info I can study up on to use as steps to working out a system that would upgrade the value of my copper scrap?
I would then leave me able to use my limited waste oils supply to melt -upgrade brass, or even in best case have enough to melt separate Aluminum and iron from things like dead auto water pumps and similar.
Any pointers would be much appreciated.
Best Wishes and good luck to All,
J

Current life philosophy "One has to Play the cards One IS Dealt, and do the best One can with that hand "

 

[Declan O'Reilly]

If you are using mostly copper wiring and high percentage copper like 98%+ you could get some good results through electroplating.

You would need an anode basket for placing your copper scrap in and then for a cathode your best bet is probably a pure copper plate although stainless steel can work too.

A copper sulfate and sulfuric acid electrolyte is normally used for copper refining.

There are plenty of resources online and some tutorials on you tube.

 

[Alondro]

I'm testing a self-contained 'battery' method for crystalizing copper. I've had success at a small scale, using a solution of metal chlorides with just a touch of nitric. I dilute the saturated metal-acid chloride solution 2-to-1 with water, and then place a copper electrode and an iron electrode opposite each other, then connect them with a copper wire outside the solution.

After a time, an electrochemical reaction begins and gradually accelerates until all the copper has formed bright crystals, both on the iron AND on the bottom of the copper electrode. It's quite an interesting effect. I'm trying to work out the exact process that's taking place so I can scale it up successfully. I'm wondering if the reduced metal crystals which fall off are acting as a 3rd electrode in the region of the flask that eventually ends up with a higher salt concentration, and that's why the reaction speeds up dramatically once the layer of crystals at the bottom of the flask begins to form.

I'm certain it's electrochemical, as during one test run in a narrow-topped flask, the copper crystals on the iron touched the copper electrode and 'shorted' the reaction: the crystals stopped growing on both electrodes and turned dark, appearing to start redissolving.