Gold Plated EWaste Pins

[Geo]

Once you get your first batch of green copper(II) chloride, save it for next time. The next time you do a CuCl2 leech, use some of the green solution instead of H2O2 to start the process.

 

[Redsox1901]

Ok just so we are on the same page I am going to take all the plated metal out and add new HCL in the same amount as the picture. I do have some green AP solution from some foils I did. Will that work? Then I will follow your instructions. Also what should I do with the old solution. Should I check it with stannous chloride?

Thank you

Joe

 

[Geo]

Ok just so we are on the same page I am going to take all the plated metal out and add new HCL in the same amount as the picture. I do have some green AP solution from some foils I did. Will that work? Then I will follow your instructions. Also what should I do with the old solution. Should I check it with stannous chloride?

Thank you

Joe

No. There's no need to replace the solution, just modify it. Add some of the green solution to what you have and add an air pump.

Also, as long as there's solid base metal in the solution, there's little to no chance it will have dissolved gold in solution. No need to test this solution with stannous chloride.

 

[solar_plasma]

@ Redsox
You said, you couldn't find the right threads, so, try to use the advanced search and look for the longer AP or CuCl2 posts by Butcher.

A quick search. Read all of them.
http://goldrefiningforum.com/~goldr...posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
Also a nice one:
http://goldrefiningforum.com/~goldr...=218263&hilit=cuprous+cupric+chloride#p218263

Old solution, very important. Butcher has written more posts about his ingenious style to use and reuse the solutions:
http://goldrefiningforum.com/~goldr...uprous+cupric+ferric+ferrous+chloride#p203499

Testing dark solution can be somewhat hard. But to be prepared for the future, search "spot plate" and "SnCl2" or "stannous" or just "purple stain"", mostly by Harold_V

This should answer most of your questions and a lot of questions,you didn't know, you wanted to ask.

 

[solar_plasma]

If you have the electrowinning unit inside the leaching vat then you risk getting free floating gold foils to deposit on the copper and become embedded. A filter bag would solve that problem easily.

First I thought of a diaphragm, but a bag makes it much easier to collect the foils.

I don't think you should use air to transport the copper(I) chloride, you want it to remain unoxidized. If you allow oxygen to it then you get copper(II) chloride and that you can't electrowin without releasing chlorine gas.

The pipe would be near the anode, where CuCl2 is produced by oxidation. Only this CuCl2 rich solution would come in contact with the air and be transported to the second tank, where it dissolves base metals and gets reduced to CuCl again, before it flows back to the cell.

The electrolyte would need to be replenished regularly as zinc, iron, nickel.... and so on would rob it of copper, but this is a perfect way to use up all our old copper chloride waste. 8)

Göran

In your electrowinning text they talk about the problem of CuCl precipitates. A problem for them, but maybe a sake for us, since we easily can reuse it.

 

[solar_plasma]

@kurtak and spaceships

Glad to hear this. I learn a lot, too, while trying to look at the things with the other's eyes, re-reading the chemistry, arguing, listening and updating my point of view. Social learning from its best side.

 

[Redsox1901]

Geo

So earlier you said to decant the solution. Should I still do this or just add the green Solution I have?

 

[Geo]

If you see the gold still on the pins, just add the green solution to what you have.

 

[Redsox1901]

Geo

Thank you so much for your help!!! I feel like such a rookie.

 

[g_axelsson]

@kurtak and spaceships

Glad to hear this. I learn a lot, too, while trying to look at the things with the other's eyes, re-reading the chemistry, arguing, listening and updating my point of view. Social learning from its best side.

Science at it's finest! 8)

The most important thing to learn is to realize you are not the same as your ideas. If someone has a better idea, embrace it. If you think you have a better idea try to explain it for them but always listen to the other side. Motivate why you believe in something.

For example, I still think using air for pumping fluids is a bad idea, but that's from my perspective. I've got a peristaltic pump that I'm not using to anything else so it's easier than trying to rig up an air pump.
My initial vision was of a closed system and an air pump either must use the air inside the system (full of HCl fumes) or the system will emit HCl fumes in the escaping air.
Another drawback is that 4CuCl + O2 + 4 HCl -> 4 CuCl2 + H2O and we probably need the HCl to dissolve the newly formed CuCl in the leaching vat. That would force us to add HCl so it doesn't stop the process by passivating the surface with an insoluble crust of CuCl.
... unless the high CuCl2 levels provides all the Cl needed to create the complex with CuCl that makes it soluble.

Another idea I've been toying with is to use NaCl instead of HCl as the chloride matrix. It would make the copper etching process possible to run at a neutral pH. Haven't thought this one through yet, just tested to dissolve CuCl in a saturated NaCl solution. That part worked just fine.

It is also possible that this process could be run in an ammoniacal medium. Many pcb factories are using ammoniacal copper chloride process for etching boards.

Another thing to think about is the electrode materials. At the cathode copper will be plated so that isn't a big deal and for example a copper or stainless steel should work fine. The anode on the other hand could see quite an aggressive environment, if the voltage gets too high chlorine could develop. Here lead anodes was used earlier as they get coated in lead chloride and is passivated by it.
Platinized titanium is another good anode material and for my tests I'm going to use it. I already got one from ebay. I've just had too much work lately to have time to go forward.

Okay, now I've dumped all my ideas I've been thinking about the last couple of months. Do whatever you want with it and let us know what you find out. 8)

By the way, this process is also mentioned in page 353 in handbook of copper compounds and a good article on anodes usable for electrowinning (at least the beginning of it can be read for free) is http://link.springer.com/article/10.1007%2FBF03222350 Use the look inside button.

Göran

 

[Geo]

From my perspective, Solar was saying the solution going from the leech heap to the electrolytic cell would be gravity fed and the lifting force to return the solution to the leech heap could be air. Serving two purposes, lifting the solution and oxygenating the solution. I like it.

 

[solar_plasma]

From my perspective, Solar was saying the solution going from the leech heap to the electrolytic cell would be gravity fed and the lifting force to return the solution to the leech heap could be air. Serving two purposes, lifting the solution and oxygenating the solution. I like it.

Yap!


The anode could be a bag full of more massive gold plated copper alloy items, continuously added new material and the leach chamber could contain fingers. This would be a combination of both approaches.

I am quite expectant. Though, some basic research is needed to evaluate if it is worth trying. A lot of possible problems: continuous feed stream of adequate material, suppress chlorine evolution, preventing passivation, accumulation of contaminant with solution's depletion of copper, maintenance of the best molarity of the chloride matrix, removing of cathode copper powders, regulation of voltage in relation to varying cell resistance....this process is obviously again quite not a "drop&forget missile".

 

[solar_plasma]

Found some good ol' threads about the subject, which like most good ideas isn't new:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=1445&p=12406#p12406

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=86&t=14380&hilit=cucl

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=7239&p=65687#p65687

Though I am not sure if anyone has written about dissolving pins or other plated massive stuff being the anode in this setting. So far I am preparing a pure "used" CuCl2/CuCl solution with known concentrations by using pure CuCl2 and pure copper. This will make it possible to see the impact of contaminants later. Further, this will make it possible to reproduce the experiment.

 

[g_axelsson]

If you let the pins have direct contact to the anode the added potential could dissolve some gold in worst case. In an experiment I managed to "cut" a gold wire used as conductor to pins on CuSO₄ + H₂SO₄ electrolyte when I raised the voltage too high.

There might have been some chloride contamination as it's really hard to avoid, especially if HCl can move between beakers.

Göran

 

[Silver Sliver]

solar, Geo, Goran

I just love reading the discussions you guys have - I learn a lot from them 8)

Kurt

Agreed!

 

[solar_plasma]

Obviously Philddreamer has used an anode from pins in a chloride before, as far as I understand the thread in the first link.

Yes, Göran, this is my greatest concern, chlorine in nascent state. We would lose one of the most important advantages: To be able to watch where the gold is.

 

[solar_plasma]

I tried a gold plated non-magnetic anode in fresh, pure CuCl2, playing with voltages between 0-24V at around up to 6A. The gold disappeared, the solution went pretty fast black-brown. I would guess the gold dissolved and reduced back to black powders. No gas at the cathode, some gas without any smell at the anode at higher voltages. There was a strong reaction taking place at the anode, pretty much as if the solution got stirred,even at voltages no gas was evolved.

Obviously all chlorine reacts immediately and doesn't gas out.

Obviously the nascent chlorine at the anode dissolves gold immediately.

Interesting, but no benefits so far.

Next I will try inert anodes, graphite or silver maybe (I am a bit nervous about the last choice).

 

[solar_plasma]

Incidentally, I use Butcher's method concentrating used CuCl2 solution by Göran's coffee maker method. It is just a pleasure to see, how much it still dissolves quite rapidly and at the same time the amounts of liquids to store and to treat reduces.

 

[Geo]

Next I will try inert anodes, graphite or silver maybe (I am a bit nervous about the last choice).

Silver is not inert in HCl. A layer of metal passivates, coating the exterior with a layer of silver chloride preventing further attack of the silver metal underneath. If you add electricity however, the silver metal will travel through the passivized layer and then convert to silver chloride. The coating will continuously be crumbling loose. Your silver anode would end up a pile of silver chloride in the cell.

 

[solar_plasma]

So I was right being nervous about that choice. I have read somewhere about silver electrodes being inert in chloride electrolyte, but maybe this was for purposes of measuring and not for that heavy duty electrolysis we do.

What electrode materials would be more adequate considering durability and cost effectivity?