# Gold Plated EWaste Pins



## Redsox1901 (Nov 14, 2014)

Hello I am really new to the site but have a great interest in refining metals. I have tried to look for any information on removing the gold plating from computer ewaste. I understand the concept of using AP for removing the foil fingers from boards and why that is done. I would really just like some guidence on where on the forum to look or some information regarding if AP and then acid/clorox would be the best technique for disolvong the plating from the pins. I was thinking about using AP to make sure that the pins are free of copper and then soak them in acid/clorox to dissolve the gold in solution. Once that is done I will precipitate it out. Please let me know if this makes sense.

Thank you!


----------



## Pantherlikher (Nov 14, 2014)

Hello and welcome to the forum.
Before touching any acid, please learn the right way to do what you are hoping to do from start to finish...
Meaning read through the forum until you know what to do when acid splashes all over you or fumes take your breath away...
Also what to do with spent acids when you are done.

Below is 2 links? URLs I found simply by typing Pins into the google custom search up top.
There you can type anything in and will show links to posts on the subject.
What you find is older posts first and has loads of good background on subject of choice. 
Reading through them you will find that the processes have become fine tuned to work best.
These 2 links covered using acid to remove all base metal from pins but this is Not the best way to do most pins.
Good reading though.


http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=37&t=1545
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=39&t=13815

Good luck and hope you learn the right way.

B.S.


----------



## Redsox1901 (Nov 14, 2014)

Thank you so much for the very useful links. I have a lot to learn but safety always comes first. I have a lot of pins from 3 main sources. Hard drives, mother boards and cd/dvd roms. So I am figuring probably copper with a coating of nickel with the gold plate? Will continue to read but if you have any hints please let me know.


----------



## g_axelsson (Nov 14, 2014)

Just one tiny detail, it should be copper based mostly, brass or bronze. Pure copper is too soft for a normal connector and would bend easily. Pins can also be iron based, for example covar pins on IC circuits.

You are correct when you note there is a nickel barrier layer between the gold and the base metal, at least on copper based pins.

Göran


----------



## Redsox1901 (Nov 15, 2014)

The AP should dissolve the brass/bronze in solution. The crock pot will probably be the fastest correct? Also, what should I use to dissolve the nickel?


----------



## kurtak (Nov 15, 2014)

be sure not to use to much peroxide in your AP or you will dissolve gold before you want to - the peroxide is only used (small amount) to kick start the reaction of copper 2 chloride

Kurt


----------



## Redsox1901 (Nov 15, 2014)

Thank you. I was planning a 3:1 solution HCL to Peroxide. From everything I have read this sounded reasonable. Do you concur?


----------



## FrugalRefiner (Nov 15, 2014)

Cover your scrap with HCl. Add a capful of H2O2. Be patient while the reaction gets started. Then, add an aquarium bubbler.

Dave


----------



## Redsox1901 (Nov 16, 2014)

I will certainly try that! Thank you so much for the suggestion. I am also taking a neodymium magnet to the pins to confirm there is no ferrous materials as a base metal. From what I have read any ferrous material can really foul up the AP bath? What would be an alternate solution for gold plate over ferrous? And would you also take a magnet to it?

Thank you!


----------



## maynman1751 (Nov 16, 2014)

If you use a powerful magnet it will also attract the non ferrous pins because of the nickel plating which is somewhat magnetic. If you are going to use a magnet to separate, use a weaker one.

Do a search for an electrolitic cell. It's the best way to do pins. Be careful with this method as it uses a very dangerous acid (sulfuric). Know what you're doing before attempting this method!!!!!!

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=18365&hilit=sulfuric+cell


----------



## Redsox1901 (Nov 18, 2014)

I want to thank everyone for their help. I am going to start the process and will let you all know. Thank you again.


----------



## Redsox1901 (Nov 21, 2014)

Ok, so i have covered the pins with the HCL and added a little H2O2. I gave it 2 days to get going at which point it was the nice emerald green everyone talks about. I then added an aquarium bubbler which has been in for 3 days now. The solution is now a brown color. I understand this to be the Copper dissolving in the solution. Just to be on the safe side I tested the solution with Stannous Cloride to confirm if any gold was dissolved (even though i only used a small amount of H2O2). Is it the correct thing to do to add more HCL to allow for more copper to be dissolved.


----------



## Geo (Nov 21, 2014)

Redsox1901 said:


> Ok, so i have covered the pins with the HCL and added a little H2O2. I gave it 2 days to get going at which point it was the nice emerald green everyone talks about. I then added an aquarium bubbler which has been in for 3 days now. The solution is now a brown color. I understand this to be the Copper dissolving in the solution. Just to be on the safe side I tested the solution with Stannous Cloride to confirm if any gold was dissolved (even though i only used a small amount of H2O2). Is it the correct thing to do to add more HCL to allow for more copper to be dissolved.



Brown is not good in AP solution. Add more HCl even if you have to move it to a bigger container.


----------



## Redsox1901 (Nov 21, 2014)

Geo,

So I've moved it to a bigger container and added more HCL. Should I expect the solution to turn back to green or just a lighter brown?


----------



## g_axelsson (Nov 21, 2014)

I think brown is okay, it is CuCl in solution. The only thing it tells you is that the solution is working and dissolving copper but it is lacking in oxygen. If you get a white sediment then it is undissolved CuCl and you need to add more HCl. CuCl needs free HCl to dissolve so the fact that the solution is brown without sediments shows it is enough HCl for the moment.
Either add more air or more patience, the copper chloride process needs a lot of the latter.

The solution turns brown with just a little bit of CuCl in solution, look at the documents on Lazersteves homepage for a color guide to the copper chloride process.

Göran


----------



## Redsox1901 (Nov 21, 2014)

Well I guess its a good thing that I do not have any white sediment at the bottom. I have noticed a lot of gold foil floating in the solution so that is also pretty good. I really think my problem is that a lot of the pins I put to solution had a lot of the base metal remaining which is now dissolved. The extra base metal would add more dissolved copper to the solution causing the browning. I have had the aquarium bubbler going 24 hrs a day for 3 days now so the amount of base metals being dissolved should be quite a bit. Please let me know if anyone has any suggestions on how I should proceed.


----------



## Geo (Nov 21, 2014)

Göran, I'm going to have to disagree with that. I've been using copper chloride for about four years and I've never seen brown copper chloride. There is brown copper chloride that I have found out but it is copper chloride anhydrous. Since copper(I) chloride is a white solid, and copper(II) chloride is a green liquid and green crystal, what copper chloride could it be if it's brown but still in solution. Green copper(II) chloride is what you want you etching solution to look like. It may get murky with copper(I) chloride when the solution gets saturated or if the PH rises above the limit of the solution to hold it in solution. Copper oxide will deposit then. I believe the brown is copper metal colloid in the solution. Not enough HCl to keep it dissolved.


----------



## solar_plasma (Nov 22, 2014)

It is oversimplified only to think of CuCl + Cl- <=> CuCl2, when it comes to the colors of the solutions.

In fact there are a lot of different complexes forming, depending on the concentrations, pH, ORP and the amount of excess HCl.


dilluted CuCl2 -> slightly blue [Cu(H2O)6]2+
medium concentrated CuCl2 -> green [CuCl2(H2O)4]
concentrated CuCl2 in HCl acidic environment -> greenbrown [CuCl4]2-

CuCl can be dissolved in concentrated HCl to form colorless(!) H[CuCl2] (this is Cu(I) or Cu+!)

(source: Holleman/Wiberg)

Now, let's think of all the possible combinations and the other metals involved...so, let's stay assuming a clean copper solution.

The brown color is obviously not CuCl, copper(I) is colorless, but from experience we know, the more Cu dissolves, the more dark the solution gets, while cHCl decreases. More HCl in an oxidizing environment is needed, obviously to bring complexed Cu(I) back to Cu(II).

If we think of precipitated white/grey CuCl, it is easier to describe, what will happen:
CuCl + HCl -> H[CuCl2] (complexing)
then
H[CuCl2] -> CuCl2 (actually complexed) + e- (oxidation)

So, saying the brown color is from dissolved CuCl is a simplification, which works well enough for our purpose. Saying CuCl is never brown, but colorless, is also correct. I think both of you are right and wrong from a point of view.


----------



## Geo (Nov 22, 2014)

Notice that I said that if the PH rises above the point that the copper in solution precipitates as an oxide, what color is copper(I) oxide? http://en.wikipedia.org/wiki/Copper(I)_oxide To adjust the PH back down to where the solution can hold the added copper, add more HCl. Copper(I) chloride (CuCl) and copper(II) chloride (CuCl2) and that's it. There's debate about the possibility of CuCl3 and CuCl4 but it's so unstable, for all intents and purposes, there's no reason to suspect it. If the solution is brown, it is not doing it's job as an etchant. The chemistry is off and something has gone wrong. The attitude that the brown color is as it should be bothers me because it is such a simple process. I don't mean to be harsh but copper(II) chloride (CuCl2) etchant, is what it is, and it should be promoted for what it is and as it should be. If we tell people that AP is working when it is brown is not true and is misinformation. I have friends that whisper in my ear when I make mistakes and I very much appreciate it but I also get called out on the things I say that are incomplete or completely wrong. Even a process as simple as AP can be chocked full of problems and dangers. Why stress over a high profile process like dissolving gold and so little effort into something like dissolving copper.


----------



## solar_plasma (Nov 22, 2014)

Sorry, I added some lines for better explanation before I saw, you already answered.

I think now it should be better to understand. Yes, we can look at it using a simplified model. Everybody knows, this model is enough for doing our work.

BUT you guys raised the question about the color and this is quite not that trivial.


----------



## solar_plasma (Nov 22, 2014)

As far as I read in my books, there is no such thing as a CuCl3 or CuCl4 and I didn't talk about that in any way.

In no way I said, it should be brown and would still work. I even showed the reason, why it stops etching, the more brown it gets.

You can't understand what I meant as long as you use the simplified model, but you have to think of oxidation states and complexes.

This way to look at things is not necessary for those, who just want to make it work, but for those, who wants to know the "why" just for the curiosity. As far as I can see, this is the most advanced explanation given, but I am open for discussion.


----------



## Geo (Nov 22, 2014)

From my understanding, there's only two ways to have brown copper in copper(II) chloride solution, (1) undissolved copper metal and (2) copper(I) oxide. If anyone comes up with a better explanation, please let me know. Either way, add more HCl.


----------



## solar_plasma (Nov 22, 2014)

Both of them are not soluble. So, how can the solution be green-brown even after filtering and/or settling?

You know I do like you and I, too, don't want to sound harsh, but you are just telling Wiberg's _Inorganic chemistry_ is wrong.


----------



## Geo (Nov 22, 2014)

Hey, that's my point. :lol: It can't be brown. If CuCl2 turns brown, then the copper metal is coming out of solution. If it was dissolved, it is coming out as copper oxide. If the metal has been chewed up by the previous chemical action, undissolved copper can be free floating. Either way, the brown color is not a copper chloride salt.

Copper(I) chloride is a solid white crystal. copper(II) chloride is a green crystal or green liquid. Neither of these two chlorides are brown.


----------



## solar_plasma (Nov 22, 2014)

concentrated CuCl2 in HCl acidic environment -> greenbrown [CuCl4]2- <------this is still Cu++!

Holleman/Wiberg Inorganic Chemistry, XXII. Copper group, 1.3 copper(II) compounds, copper(II)chloride

So, as long there is anything green in it, it will etch, but of course it will slow down, when the excess HCl is used up, since the copper chloride system only works as a catalyst, but it is the HCl that does the work on the long run.

It should not wonder if copper metal forms, especially if more reactive metals are present, but I looked at a pure copper system.


----------



## Geo (Nov 22, 2014)

Electronics will seldom be pure copper.

If I placed some copper metal in a container and added a small amount of copper oxide, I would have created AP solution. If the solution is left undisturbed, either the copper will dissolve (if there's enough acid) or, only the amount of copper the solution can hold (saturation point) will dissolve. Any added energy, (temperature changes (heat) or stirring (vibrations) will effect how much copper the solution will dissolve. If the temperature rises, the solution dissolves more. As the solution cools, the excess copper will precipitate out as CuCl (a white powder). If the solution reaches it's saturation point and the reaction depletes the solution of hydrochloric by either heating and cooling or adding oxygen and then stopping the oxygen, brown copper oxide will precipitate out.


----------



## solar_plasma (Nov 22, 2014)

I have no doubt about the phenomenon as it is perceived. About the reactions and compounds I am more cautious to jump at conclusions. Maybe I find a way to implement your point into the theory from the books.


----------



## jeneje (Nov 22, 2014)

I never seen where he said they were copper pins (i think we all assume they are) they may be plated over iron. If they are, the solution will turn brown as the HCL used in the AP dissolves the iron into solution. If adding air with more HCL doesn't re-dissolve the copper then i would suspect iron. Just a thought. :| 
Ken


----------



## solar_plasma (Nov 22, 2014)

Most likely.

I can't see any reason, why a pure copper chloride system should reduce copper to anything else but CuCl or its complexes in solution.

Iron, nickel and zinc might, though. And a lot of brown iron compounds will possibly be involved,too.


----------



## g_axelsson (Nov 22, 2014)

Hey guys! Slow down! Ten additional replies while I've been researching my answer... gee, talk about being left in the dust... :mrgreen: 
I'm going to post this as it is and then read the rest of the replies.



Geo said:


> Göran, I'm going to have to disagree with that. I've been using copper chloride for about four years and I've never seen brown copper chloride. There is brown copper chloride that I have found out but it is copper chloride anhydrous. Since copper(I) chloride is a white solid, and copper(II) chloride is a green liquid and green crystal, what copper chloride could it be if it's brown but still in solution. Green copper(II) chloride is what you want you etching solution to look like. It may get murky with copper(I) chloride when the solution gets saturated or if the PH rises above the limit of the solution to hold it in solution. Copper oxide will deposit then. I believe the brown is copper metal colloid in the solution. Not enough HCl to keep it dissolved.



Well, I have run copper chloride since Steve brought the process to the forum. I made some big mistakes from the beginning before it was realized that too much peroxide also dissolved gold. I might not run the fastest process since I've never bothered about speed and got scared of dissolving gold from my first runs.

Copper(I) chloride is not soluble in water, but in a high chloride matrix it is (for example HCl, NaCl or even AuCl3 though I haven't tested that one yet!)

If you take a look at the _goldrecovery_documents_CuCl.pdf document at Lazersteves site you have on page 10 a nice picture of Cu1+ ions in solution in a Cu2+ etchant. At 4g/liter it has a clear brown tone and at 10g/liter it is definitely brown.



solar_plasma said:


> CuCl can be dissolved in concentrated HCl to form colorless(!) H[CuCl2] (this is Cu(I) or Cu+!)
> 
> (source: Holleman/Wiberg)
> 
> ...


That last formula isn't balanced. Shouldn't it be
H[CuCl2] -> H+ + CuCl2- (+something about complexed)

Anyhow, I had a hard time finding anything about the color except from Steves page. Then I found "Handbook of Copper Compounds and Applications" (Google books) and it states :
"The colorless solution contains essentially copper(I) ions. Small amounts of copper(II) ions in the presence of copper(I) ions darkens the solution significantly and it is suspected that a charge transfer between the copper(I)-copper(II) complex is responsible for the intense coloration."

Maybe the CuCl isn't responsible for the color by itself, but it seems it is an integral part of the coloring and that it can be used as an indicator of how high the concentration is.

After reading through many of these documents again I agree, running with high concentration of CuCl will slow the process down. Seems we all were correct in parts. 8) 

Göran


----------



## solar_plasma (Nov 22, 2014)

Hey you're right, I missed that H. Maybe something like that:

-[CuCl2] -> CuCl2 (actually complexed) + e-

Thanks for the link! It looks as if all of us are into some valuable points. And the synthesis of those points seems to bring us closer to the understanding of the whole as is.


----------



## solar_plasma (Nov 22, 2014)

Take a look at p.69, electrolysis of CuCl:

It seems to be possible to dissolve base metals at the anode without chlorine evolution and deposit copper metal at the cathode. That leaves only the question, if gold plating will dissolve, too, because of the oxidizing environment. If not, this could be a nice CuCl2-etchant modification.

edit: I think I'll try this as my next project with a concentrated, spent solution, very low voltage (0,679V?) and maybe some kind of diaphragm.


----------



## g_axelsson (Nov 22, 2014)

Yes, I found out about that 2 CuCl -> Cu + CuCl2 electrolysis process when researching electrowinning from a chlorine solution a couple of months ago. Just as you write, the problematic part is chlorine production and attack of the electrode. I was going to write about it but haven't had time to do any experiments yet.
I don't think the gold plating will dissolve if you use the CuCl2 for etching and if it did it would end up with the copper and that we could run in a copper (sulfate) cell without problem after melting the pure copper.
You could pump the renewed copper(II) chloride into a leach vat and draw off spent solution of copper(I) chloride in a continuous operation or batch wise renew the etchant.

There isn't a lot written on electrowinning from chloride solutions but at least I found this article.

Have fun! 8) 

Göran


----------



## solar_plasma (Nov 22, 2014)

I love it! This text contains a lot of information I was longing for. Thanks!

I have to re-read it several times to see, in what direction it affects the idea of an electro-renewing CuCl2/CuCl reactor for the purpose of dissolving base metals under gold plating or even de-plating thick pieces. 

Your idea with a second tank might be the way to go. A pipe with an air bubbler could be used as an acid resistant pump, just like in small cheap fish tanks. The flow back could be achieved by gravity. If just chlorine evolution can be completely suppressed...

But only using one chamber would have the advantage that the CuCl2 would get used as soon as it evolves, dissolving the base metals of the gold scrap anode. And my stomach says, this could prevent chlorine evolution.


----------



## Redsox1901 (Nov 22, 2014)

View attachment Attachments_20141122.zip


I have included an attachment of pics so you can see what I am talking about. Any assistance would be greatly appreciated.


----------



## kurtak (Nov 22, 2014)

solar, Geo, Goran

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

Kurt


----------



## g_axelsson (Nov 22, 2014)

solar_plasma said:


> I love it! This text contains a lot of information I was longing for. Thanks!
> 
> I have to re-read it several times to see, in what direction it affects the idea of an electro-renewing CuCl2/CuCl reactor for the purpose of dissolving base metals under gold plating or even de-plating thick pieces.
> 
> ...


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.

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.

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


----------



## Anonymous (Nov 22, 2014)

kurtak said:


> solar, Geo, Goran
> 
> I just love reading the discussions you guys have - I learn a lot from them 8)
> 
> Kurt



I was going to post something but Kurt you said it better than I could have done. So I didn't. I love the good natured disagreements and info gained from them. Thanks lads.


----------



## Redsox1901 (Nov 22, 2014)

So does anyone have any ideas on how I can fix my mistakes? I am not even quite sure what the problem is. Us there a way to test for problems? I have been reading threads all day and haven't found the answers. 

Thank you 

Joe


----------



## Geo (Nov 22, 2014)

Redsox1901 said:


> So does anyone have any ideas on how I can fix my mistakes? I am not even quite sure what the problem is. Us there a way to test for problems? I have been reading threads all day and haven't found the answers.
> 
> Thank you
> 
> Joe



It looks like the solution dissolved something but it's not copper. Decant the solution and take a piece of the metal and wipe it off good and make sure the gold plating is still intact. The amount of solution in the pictures is good. If the plating is still intact, add it all back to the container and add a small amount of H2O2 and watch for a color change in the solution. It should go clear and then some shade of green. Add an oxygen source like a fish aquarium pump. It wouldn't hurt to find some green copper oxide to add to the mix.


----------



## Geo (Nov 22, 2014)

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 (Nov 22, 2014)

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 (Nov 22, 2014)

Redsox1901 said:


> 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 (Nov 22, 2014)

@ 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 (Nov 22, 2014)

g_axelsson said:


> 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 (Nov 22, 2014)

@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 (Nov 22, 2014)

Geo

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


----------



## Geo (Nov 22, 2014)

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


----------



## Redsox1901 (Nov 22, 2014)

Geo

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


----------



## g_axelsson (Nov 22, 2014)

solar_plasma said:


> @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 (Nov 22, 2014)

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 (Nov 23, 2014)

Geo said:


> 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 (Nov 24, 2014)

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 (Nov 24, 2014)

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 (Nov 24, 2014)

kurtak said:


> solar, Geo, Goran
> 
> I just love reading the discussions you guys have - I learn a lot from them 8)
> 
> Kurt



Agreed!


----------



## solar_plasma (Nov 25, 2014)

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 (Nov 26, 2014)

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 (Nov 28, 2014)

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 (Nov 28, 2014)

solar_plasma said:


> 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 (Nov 28, 2014)

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?


----------



## Geo (Nov 28, 2014)

I think hardened graphite would be best.


----------



## g_axelsson (Nov 28, 2014)

solar_plasma said:


> 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?


http://goldrefiningforum.com/phpBB3/viewtopic.php?f=34&t=21454&start=40#p221929 :mrgreen: 

Göran


----------



## Geo (Nov 28, 2014)

It's true that titanium is a better quality anode but from the perspective of the frugal minded, titanium is twice as expensive as graphite. On Ebay, a 12"x12"x1" sheet of graphite is about $20 and a 12"x12"x.015" sheet of titanium is around $40.


----------



## joecool1962 (Dec 16, 2014)

thank you and i enjoy all the reading, hopefully i'll add some good info, and eventually some pictures, if i can figure out how to get them on


----------



## necromancer (Dec 16, 2014)

joecool1962 said:


> thank you and i enjoy all the reading, hopefully i'll add some good info, and eventually some pictures, if i can figure out how to get them on




there is a tutorial on uploading photos. take a peek, not sure it will be the same for all users but may help

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=20488


----------



## FrugalRefiner (Dec 16, 2014)

And another here: Attaching Images or Files, Working with Attachments.

Dave


----------

