Processing Fingers with CuCl2 etching solution

[maynman1751]

If you see something I say without motivation and you don't know why, put me to the test. If I'm wrong then I want to be corrected.

Goran;
I really don't feel qualified or experienced enough to question someone, like you, who has much more knowledge and time involved in this forum. I've learned a lot reading your posts and respect your judgement. I wouldn't question you anymore than I would Harold, Butcher, GSP, Geo or any other veteran of this subject. I do, on occasion, give advice on subjects that I am comfortable with and am always open for correction. I'm here to learn from the best and not to question their experience. I guess it's just a matter of respect!

 

[purgatory]

Hi
How are you all doing?

Well, thank you so much Goran, Geo and Maynman for the suggestions, I highly appreciate them all.

Goran, I have noted down your suggestion regarding diluting the H2O2 concentration, one more point has been cleared in your post that I will not need to boil the foils in HCL after getting then stripped off. Thank you so much Goran for your kind help, i am not undeceisice anymore the way I was last night, actually I have invested a lot of money over e-scrap, which was the reason behind my frustration. I will start the new session within a day or two and will post my feed back regarding it and your suggestions will be needed, I hope you will not mind. Thank you Goran one more time.

Maynman, Thank you for your clarificatiin regarding de-ionizes water. I appreciate it and will surely watch Sam's video also, so nice of you.

Geo, I want to run a batch of almost 10 to 12 lbs of golf fingers from the memory Ram Sticks and other boarda also.

Take good care of yourselves
Have a good night

Alvi

 

[Harold_V]

maynman, we all learn from each other by discussing these topics. For example I had to think a lot of why it would benefit to boil the foils in HCl. The only reason I could find was first to remove aluminum or some steel that would resist nitric acid.
Then when we drifted in on the copper chloride process I had to think hard until it hit me that any leftover CuCl wouldn't dissolve in a water wash only. Depending on how far you push the process you end up with various amounts of CuCl, so for someone maybe the HCl wash is necessary, and boiling it will speed up the dissolving process.

By thinking about the details I have learned some more and gained a deeper understanding of the process. I thank you for that and hope we both and others too have learned something in this thread.

Frankly, if I was involved in processing these products by the methods being discussed, not only would I do a prewash in heated HCl, I'd also incinerate first. There's great benefit doing both.

One of the things I discovered after having problems with filtration is that a prewash with HCl and a rinse with (tap) water will generally dissolve and remove contaminants that restrict filtration. It does little to control oils, which tend to float gold, so incineration is very desirable as well, with the added benefit of reducing the volume of solids, some of which may actually absorb and retain values (activated carbon, for example). The added work is often rewarded with higher quality and shorter filtering time. I found both of them indispensable.

Harold

 

[Anonymous]

Harold.

Why would you incinerate recovered foils from IT equipment please? I can see absolutely no benefit from this after having processed an awful lot of them.

I understand the HCl washes and water washes and completely support you on this however the incineration I find incredibly hard to understand or agree with.

Regards

Jon

 

[Geo]

From what I understand, since lead was removed as solder and replaced with tin, the tin carries over from one process to another. Since some use nitric acid to remove base metal and the base metal contains tin, you get metastannic acid (hydrated tin oxide). If you remove base metal with copper(II) chloride, the tin is oxidized to just tin oxide. Either way, incineration helps to reduce the tin oxide to elemental tin which can be removed in a hcl bath.

 

[Anonymous]

Well I've never had that problem Geo.

It's theoretically possible I agree but I've never needed to incinerate escrap foils, and I've done an awful lot of them. So respectfully I think it's overkill and potentially a way to lose some of the gold if the incineration process isn't clinical.

 

[rickbb]

It all depends on how clean your gold plated e-scrap is to start with.

If I'm doing just trimmed fingers then I do not prewash in hot HCL beforehand.

But if I have whole cell phone boards that have gold plating everywhere and trimming it out is just not practical, I do a very prolonged hot HCL bath and rinsing. This gets rid of all that tin/antimony solder left over from depopulating.

Some people just dump in everything, cell phone boards, trimmed fingers, pins, broken CPU chips. In those cases a pre-soak in HCL and incineration would be greatly helpful.

 

[Geo]

When I first joined the forum, there was much more emphasis on achieving four 9's when refining. 99.95 is still hard to do when working with electronics. The importance of removing tin is two fold. first, it will report in your final melt. Tin will follow gold through all the processes to the end (much like silver) unless it's removed correctly. Secondly, just like tin in hcl makes stannous chloride, tin in our refining solutions will make stannous chloride causing precious metals to form a colloid. If there is not enough oxidizer in solution to overcome the tin, a colloid will form. Unless you know what all the different colors a gold colloid can make, you may mistake that red-blue-purple color as something else and misplace your gold.

 

[Harold_V]

Harold.

Why would you incinerate recovered foils from IT equipment please? I can see absolutely no benefit from this after having processed an awful lot of them.

I understand the HCl washes and water washes and completely support you on this however the incineration I find incredibly hard to understand or agree with.

Regards

Jon

What little escrap I processed I did with nitric acid. The purpose of incineration I have already outlined. It serves a very useful function, both in improving quality and in ease of filtration. You may, or may not, benefit by those two functions (incineration and a prewash with HCl), but I'd be totally surprised if you didn't see a difference in the outcome.

If you have not tried, you have no clue, just as I have no clue about what you experience. All I can say is that if you have any difficulty in filtration (if you can't gravity filter, you're having trouble), you would be well advised to use both of these procedures. Each has the potential to be an "a-ha" moment.

I've noticed a general attitude on this board about not incinerating, which I find rather strange. The cleanest of objects often benefit.

Harold

 

[4metals]

I agree with Harold as to applying a general across the board incineration step. It will never hurt and skipping it may very well hurt.

I think there may be a resistance to incineration because some may feel that to incinerate one needs a high temperature chamber and an afterburner. While that is true for large quantities of sweeps and electronics, often a torch and a metal pan in an exhaust hood will serve.

I think it would be helpful for some of our members to show us their incineration hardware. It may make it easier for everyone to understand the process does not always have to involve high tech equipment and controls.

 

[Anonymous]

4metals my understanding of incinerating foils would be primarily to remove grease and oils. Correct me if I'm wrong but given that the majority of IT scrap comes from an environment where people are not wearing it close to their skin, and in many cases in an air controlled environment where does the grease come from?

I understand and believe the necessity for this part of the process when it's jewellry, but given the fact that the AP part of the recovery process reveals the sides of the foils that have never been in touch with the air, how would incineration improve the refining process?

If I'm missing something fundamental then please feel free to show me the error of my ways.

Kind regards

Jon

 

[Anonymous]

Harold.

Why would you incinerate recovered foils from IT equipment please? I can see absolutely no benefit from this after having processed an awful lot of them.

I understand the HCl washes and water washes and completely support you on this however the incineration I find incredibly hard to understand or agree with.

Regards

Jon

What little escrap I processed I did with nitric acid. The purpose of incineration I have already outlined. It serves a very useful function, both in improving quality and in ease of filtration. You may, or may not, benefit by those two functions (incineration and a prewash with HCl), but I'd be totally surprised if you didn't see a difference in the outcome.

If you have not tried, you have no clue, just as I have no clue about what you experience. All I can say is that if you have any difficulty in filtration (if you can't gravity filter, you're having trouble), you would be well advised to use both of these procedures. Each has the potential to be an "a-ha" moment.

I've noticed a general attitude on this board about not incinerating, which I find rather strange. The cleanest of objects often benefit.

Harold

Ok Harold good point. Sounds like it's worth an experiment. I've got a good sized batch to process in just over 2 weeks so I'll try an experiment. Like you I do use Nitric to recover so what I'll do is take 50% of the batch and process as normal and 50% and incinerate prior to refining.

I know that we do disagree on a number of things but you'll probably also accept that I'm enough of a straight arrow to admit it if your additional step works better. Does that work for you Sir?

Jon

 

[Barren Realms 007]

Harold.

Why would you incinerate recovered foils from IT equipment please? I can see absolutely no benefit from this after having processed an awful lot of them.

I understand the HCl washes and water washes and completely support you on this however the incineration I find incredibly hard to understand or agree with.

Regards

Jon

What little escrap I processed I did with nitric acid. The purpose of incineration I have already outlined. It serves a very useful function, both in improving quality and in ease of filtration. You may, or may not, benefit by those two functions (incineration and a prewash with HCl), but I'd be totally surprised if you didn't see a difference in the outcome.

If you have not tried, you have no clue, just as I have no clue about what you experience. All I can say is that if you have any difficulty in filtration (if you can't gravity filter, you're having trouble), you would be well advised to use both of these procedures. Each has the potential to be an "a-ha" moment.

I've noticed a general attitude on this board about not incinerating, which I find rather strange. The cleanest of objects often benefit.

Harold

Ok Harold good point. Sounds like it's worth an experiment. I've got a good sized batch to process in just over 2 weeks so I'll try an experiment. Like you I do use Nitric to recover so what I'll do is take 50% of the batch and process as normal and 50% and incinerate prior to refining.

I know that we do disagree on a number of things but you'll probably also accept that I'm enough of a straight arrow to admit it if your additional step works better. Does that work for you Sir?

Jon

After you incinerate you should do a couple of washes in hot HCL for a while and a couple of water washes then finish processing the first go round.

 

[4metals]

Funny thing about scrap is you never know where it has been. If you have a lot that had a lot of solder and you treated with nitric, a quick torching and Hydrochloric Acid treatment before Aqua Regia can save you the dreaded drip.

Another way to look at it is why you are refining and your time schedule. Maybe if you get a dripping filter you can turn around and go back in the house to watch another movie but if you do it for a living and have a finite area to ptocess in it can really matter. I know Harold had his own refinery and didn't want to kill a day watching a filter drip. Time is money. When I had a refinery it was frustrating to go in the back and see 3 guys standing around while filters go drip drip drip. For that reason I made procedures that covered all bases. Could a good operator skip a few steps when he knows the material? Sure. But it has been my experience to have general rules that are followed for different families of scrap will save more time in the long run.

But from a learning perspective you should split the lot.

 

[Harold_V]

I know that we do disagree on a number of things but you'll probably also accept that I'm enough of a straight arrow to admit it if your additional step works better. Does that work for you Sir?

Jon

As I no longer have a dog in this race, sure, I have nothing to lose. I know what worked for me, and it came only from having bad experiences. I had no one to turn to.

Give it a go. If you're using nitric, as you suggest, and you get even a trace of solder involved in your processing, you stand to benefit greatly. The incineration will remove substances that absorb fluids, and the HCl wash will remove substances that make filtration difficult.

Gather all of your gold, after stripping, which should be heated in a fry pan, from below. It need not be dry, as the heating will quickly dry the material. When the pan is hot enough, you'll see that substances are being burned off. How can that not help?

Raise the temperature of the pan by playing a torch on the bottom. Make sure the pan is an old stainless type---do not use cast iron, nor should you use a pan with plating on the exterior (copper or aluminum). You should heat the pan until you have achieved the temperature that ignites carbon. Once that hot, play a small stream of oxygen on the contents of the pan. Any carbon that remains will glow brilliantly. No glow---the job is done. Wash in (heated) HCl, then rinse with tap water. Do not filter, simply siphon off the solution, and repeat the rinse if necessary. A couple rinses are often enough. If you wish to hasten settling, rinse with hot water instead of cold water.

Do not remove the contents from the beaker. After the final rinse, leave behind a little rinse water, so you don't siphon off any of the values, then add the solvent of your choice to dissolve the values.

I applied this process when I ran gold filled, in particular, eye glass frames, which I ran by the thousands. The difference in filtration was astounding.

Harold

 

[g_axelsson]

I apologize, I forgot about incineration. That is a tool I seldom use as I don't have a suitable place and equipment to perform incineration where I do my other processing.
Consequently I do have problem with slow filtration but as I'm only a hobby refiner I can work in my own pace.

If... correction, when I have a proper lab, incineration will be one of my basic tools of refining.

Göran

 

[solar_plasma]

When this discussion started, I would not have believed, there will come anything interesting for me. Now, it has been developed to something that sounds like a discussion between Sokrates and Platon. Thank you all very much!

Too, I haven't incinerated, if I saw that I most probably could jump over this step (no tin or other metals, that cause problems, no carbon, no shifting from HCl to HNO3 and vice versa), - in a school lab I feel often I haven't the time for a proper incineration and I can only incinerate small amounts at a time.

But now I have understood, why the filters sometimes only drip and other times filter that fast they almost not seem to be present.

 

[purgatory]

Hi everyone
How are you all doing?

Harold, I'm glad that I processed those fingers in Nitric Acid and posted the process here to findout my mistake. After that post so many productive points I came to know about this process, I have noted down all the necessary steps for my upcoming recovery of gold from gold plated circuit boards, which are heavily gold plated on the front side of it and compleletely gold plated from the back side of it, I will post pictures and I hope the similar process could be used to get this gold stripped from these telecom circuit boards, I really need to know the price of these boards and offcourse the yield also so that I would not make a mistake in buying it at the right price.

Quick question, in my previous experiment/recovery process, I used Nitric Acid to strip the gold from Memory Ram gold fingers, can I use Nitric Acid to strip the gold plating from Telecom Circuit Boards?
Few boards I found out that they all are completely gold plated on the backside on top of pure copper plate, is that possible? Offcourse these are not Telecom Boards but they are quite old boards. Should I use Sulfuric Acid cell to deplate the gold from these copper boards/plates/sheets after depopulating them?
I'm so curious to learn about recovery and refining of precious metals, I have been reading Hoke's Book also and hopefully complete it within a short while.
I was so depressed before joining this forum, but I'm glad I joined it as I'm learning a lot on daily basis. Hopefully with in near future I will master recovery process atleast from circuit boards.
Thank you everyone for supporting me in my way of learning journey, I appreciate it. So nice of you all.

Alvi

 

[Geo]

Quick question, in my previous experiment/recovery process, I used Nitric Acid to strip the gold from Memory Ram gold fingers, can I use Nitric Acid to strip the gold plating from Telecom Circuit Boards?

Do they have solder on them at all? In any amount? If you use nitric acid as a copper leach in the presence of tin, be sure you know how to deal with metastannic acid first.

 

[purgatory]

Hi Everyone
How are you all doing?

Geo.... Yes these boards do have little solder on them, one side which is completely gold plated has no solder but on the other side where the SMD (surface mounted devices) are soldered with solder offcourse.
No Geo, I'm aware of metastannic acid, I have read many posts where it is advised to be carefull when dealing with metastannic acid. But I did not deal with it earlier, could you please elaborate a bit of it like which step I will have to be carefull in in terms of metastannic acid? The only bit I know is like it explodes when dry, Hoke's book chapter dealing with mixed scrap jewlery (gold plated, gold filled and other jewlery where solder is involved), that was the reason may be Hoke instructed not to dry it whille rinsing, she instructed to keep some water on top of the powder.

Could you please elaborate a bit more like which step or steps I must be very carefull in terms of metastannic acid?

Let me post few pictures of these boards.

Alvi