# removing gold from copper?



## pazsion (Jun 5, 2011)

Why can't i just heat the gold plated copper to 500*f and let the gold drop off?

I'm pulling pins from cpus and also notice some copper wires and other assorted pins on mb, hd's etc. That should also contain gold. 

copper melts or burns at a much higher temp..say 700*f 

my inexperienced brain says this should be all that is needed, But i wanted to ask others who may be more experienced.. I also wondered if simply repeating the process, and scrapeing the copper off the top, would be a simple way to purifying the gold that was extracted?


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## butcher (Jun 5, 2011)

they just alloy together, when you add a metal to another you change the melting temperature of the new formed alloy.
my inexperienced brain says this should be all that is needed, read up on the forum and you will then have a more experienced brain.


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## pazsion (Jun 5, 2011)

I did, i read everything available, most suggested dangerous chemicals and complicated processes, with ill results.. which is why i made a post asking about a simpler process

the copper should not alloy with the gold, and the proper heat should release the gold from the copper, this is what i'm suggesting. Why would this not work, specifically. And how can i make it work.. with just heat. I realize this isn't a perfect way to extract gold, but it should work somewhat.. being gold is heavier then copper, it will float to the surface in liquid form. 

At a certain point if too much heat is used, you'd probably just atomize everything..

also, what is the new melting point of the typical 80/20 copper/gold alloys?

If you feel i missed a relevant post (searching did not help me) Please feel free to suggest a few threads.


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## Barren Realms 007 (Jun 5, 2011)

Metal melting points.

Copper 1981 F
Gold 24K 1945 F

http://www.saltlakemetals.com/MeltingPoints.htm


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## pazsion (Jun 5, 2011)

thank you kindly xD this chart helps alot!


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## Palladium (Jun 5, 2011)

What you are trying to do is a metal separation process called sweating.
But you must have a considerable difference in temperature between the two metals you are sweating.


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## pazsion (Jun 5, 2011)

yes, and there's only an estimated 20-40*F melting point diffrence between copper and gold of any kind...this may prove more difficult then i had originally thought. 

Thank you, this term, sweating metal, will most likely help me fine tune things. 

since gold should fall, do you think if i kept the top of the metal cooler then the bottom...That it may work a bit better?


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## Palladium (Jun 5, 2011)

You need to just forget about that idea. Just a waste of time and effort. 
Take time and use the search function here on the forum and read, read, and read some more.


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## Harold_V (Jun 5, 2011)

pazsion said:


> I did, i read everything available, most suggested dangerous chemicals and complicated processes, with ill results.. which is why i made a post asking about a simpler process


Accept this comment in the spirit in which it is offered. 

If you can't stand the heat, stay out of the kitchen. 



> the copper should not alloy with the gold, and the proper heat should release the gold from the copper, this is what i'm suggesting. Why would this not work, specifically. And how can i make it work.. with just heat. I realize this isn't a perfect way to extract gold, but it should work somewhat.. being gold is heavier then copper, it will float to the surface in liquid form.



<<<<<<<<<<<<<Sigh>>>>>>>>>>>>>>

Son, you need to do a lot more reading and a whole lot less thinking. 

Here's some things for you to consider:

Gold and copper melt at very similar temperatures. 
Gold and copper readily alloy.
Molten metals are strong solvents of other metals, so once one is molten, even if the other melts at a temperature even 1,000° higher, you can expect some of it to be dissolved by the molten one. All of it, given enough time, up to the point of saturation, or a temperature high enough to melt everything. 
Metals, once alloyed, rarely can be separated by gravity. In other words, in spite of all the logic you want to throw at this, gold, which is about 2½ times heavier than copper, will not stratify once they are melted together. There are a few metals that will not remain in solution ---but that isn't of much use in refining aside from, maybe, separating gold from iron by using silver. That's not likely something you'll encounter. 

Are you reading Hoke? 

If not, why not? 

If you persist in posting when you have no clue about the processes involved in refining, it won't take long for you to wear out your welcome here. We help anyone in need, but we fully expect them to do their part in gaining enough knowledge that they understand the processes, and how to make tests. That limits the questions they are asking, many of which should not be asked at all. All of that is in Hoke. 



> At a certain point if too much heat is used, you'd probably just atomize everything..


Yes, that's true, although how you'd achieve the temperature required is a mystery to me. 

Harold


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## qst42know (Jun 5, 2011)

> If you feel i missed a relevant post (searching did not help me) Please feel free to suggest a few threads.



Refiners know it can't be accomplished by the method you suggest so there won't be a thread to find. Perhaps some classes in physics might expand your understanding. Some web browsing for "atoms in a solid" or "atoms in an alloy" might help.


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## goldsilverpro (Jun 5, 2011)

What you want to do is impossible. Don't waste your time. Study the forum.


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## Claudie (Jun 5, 2011)

pazsion said:


> I did, i read everything available, most suggested dangerous chemicals and complicated processes, with ill results..




That's how rumors get started. :| 
Where did you read about ill results?


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## goldsilverpro (Jun 5, 2011)

Like Harold and Harry Truman said, "If you can't stand the heat, get out of the kitchen." If you have a great fear of working with chemicals, you are more apt to get hurt. If you fear chemicals, you should find a different hobby.

If you want success in this endeavor, it will require using dangerous chemicals. Occasionally, someone may sort of reinvent the wheel but, most often, it will end in failure. The best way is to use proven processes. There is adequate info on the forum to keep you and others safe while achieving success.


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## butcher (Jun 5, 2011)

Gold plating can be dissolved by solder at a soldering irons temperature. As Harold say's the lead/tin solder molten becomes a solvent of gold, far below golds melting temperature.

Molten metals are strong solvents of other metals, so once one is molten, even if the other melts at a temperature even 1,000° higher, you can expect some of it to be dissolved by the molten one.


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## goldsilverpro (Jun 5, 2011)

C'mon Richard,

You really don't that's a practical method, do you? A little gold, along with a little copper, alloyed with a bunch of Pb/Sn.


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## butcher (Jun 5, 2011)

GSP, I think you misunderstood my intentions of the post, this was not a process. 

I was trying to give an example of how metals can react when melted together, well in this case even soldering pins to a circuit board dissloves some gold.

edit to correct word.


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## Palladium (Jun 5, 2011)

Yeah, i had to do a 2nd take on the wording to understand what was going on myself.


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## pazsion (Jun 6, 2011)

goldsilverpro said:


> What you want to do is impossible. Don't waste your time. Study the forum.




o.0 its a process currently used to make and refine gold... I just didn't know the exact terminology. Nothing is impossible!

"hoke" returned much more relevant results, one of which was my post. Which shows that there is little specific data under this title and wording. So i hope it helps other people who come here, learn quicker and get the info they are seeking, without the flaming and time consuming dead end searchs and reading of indirect and misdirected posts. 

Thank you paladium, I will read these links you have provided in your siggy, which i learned was what you were referring to after searching "hoke". I probably would have already known of this person, if he hadn't been edited out of our history books?? :? 

It wasn't my intention to ruffle feathers, Just get a heading somewhere. And some re-direction where otherwise i was just going in circles and reading stuff that didn't apply to what i was seeking. So i was learning nothing i didn't already know about. 

I came here to learn. And also to prevent any round abouts (forums / threads that simply stated, everything is here in this forum, go read it. Instead of provideing the more specific info in the thread posted.) If i had become knowledgeable from reading those, i would not have posted a new thread asking for more info about my chosen method of extraction. 

I will try sweating first, before i go wasteing money on more expensive trial and error, with hazardous chemicals. Which would not only hurt or kill me, but also my family and the surrounding area. Heat i can isolate, insulate, and control, much better then corrosive vapors I can not see, or seal...some of which need speacial materials and equipment to do so safely. 

And even then its not fool proof and from what i've read in the forum, several times, over several posts, could completely destroy both the copper and the gold to the point where "none exist anymore". Which would have made it a complete waste of time, money, and the material used. :|


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## Sodbuster (Jun 6, 2011)

pazsion:

You could always try it with the solder on a piece of wire that had been soldered properly, 
or see if you can remove all the solder from a copper pipe that had been sweated. 

Practice with copper and lead first so you don't risk losing your gold. Copper and lead have a greater melting temp difference and should be easier to work with. 

As stated above, (by some of the wisest and most knowledgeable of this forum) I think you will find this is next to impossible, and any gold that you did remove would be an alloy of two or more metals, and would need further refining ( with chemicals) anyway. 

Just a little challenge for you: When you can remove ALL the solder from a piece of copper pipe or wire with this method, I will eat crow.

Ray

PS: 
Welcome to the GRF


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## butcher (Jun 6, 2011)

pazsion,
Please do not get the wrong Idea, everyone here wants to help you succeed, most answers are not just directed at you, but also to help all who read the forum. we are very quick to keep the information on this forum as accurate as we possibly can, nothing against you or your idea.

If only refining metals was that easy just heat and control temperature to purify them or remove one metal from all the others. 

Actually refining is easy, and safe, when done properly.

Removing most of the lead from a copper pipe solder joint would be fairly easy. Just heat and use acid flux and a brush to brush it off then some sand paper.

Separating copper and gold would not prove so easy with heat. Otherwise we could just change karat with heat, some copper may oxidize but not much at all and it would just be a waste of energy and fuel to try, adding a flux recipe can help but still not much copper would be removed by oxidation, the alloyed metals do not have the same melting temperatures as the metals used to make the alloy.
I believe that karate gold will have a different melting temperature than pure gold, and I suspect different karats, or alloys (yellow, rose, white) would have differing melting points although I suspect possibly a subtle difference, maybe someone with more experience in the jewelry trade will confirm or tell me I am wrong.

I believe you will find it easier to make an alloy with two metals using heat than trying to separate an alloy into its individual metals.

No harm done by experimenting with your Idea, that how Edison made the light we still use today, now how many times did Edison say well that experiment did not work, that *%#@% wire just burnt up, till he thought of getting rid of the air? And how many thing did he prove to himself just would never work?


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## Harold_V (Jun 6, 2011)

pazsion said:


> goldsilverpro said:
> 
> 
> > What you want to do is impossible. Don't waste your time. Study the forum.
> ...



Ok, this is getting beyond something I intend to tolerate. 

Please post cites that substantiate your claim that the process is used to "make" gold---or even one that suggests it is used to refine gold. That simply isn't true, and nothing you can say will make it true. Gold may be recovered by the use of copper (which is a common carrier of values that are extracted in copper cells in the way of slimes), but no gold is "made", nor is it refined due to copper. Copper is the enemy--it is one of the many elements that must be removed in order to bring gold fine. 



> "hoke" returned much more relevant results, one of which was my post. Which shows that there is little specific data under this title and wording. So i hope it helps other people who come here, learn quicker and get the info they are seeking, without the flaming and time consuming dead end searchs and reading of indirect and misdirected posts.


What I hope they learn is that they should not come to a forum where you have the benefit of more than 100 years of practical refining experience, and try to tell them how things work, as you have done. I also hope they have enough wisdom to start off by reading Hoke's book, which is the only book known that takes a novice by the hand and teaches how to test, how to make testing solutions, and how to refine. Until you, or anyone, has this basic knowledge, the questions that will be asked will do nothing but annoy those of us that try to help. It's no different from asking a brain surgeon how to operate on a brain when you have no knowledge of surgery. It can be just as deadly, too. Further, don't you think it's a little foolish to argue with experienced people over an ill conceived idea (I call it a hare brained notion) when you don't have even a basic understanding of anything even remotely related to refining? In short, you are irritating me no end at this point. 



> Thank you paladium, I will read these links you have provided in your siggy, which i learned was what you were referring to after searching "hoke". I probably would have already known of this person, if he hadn't been edited out of our history books?? :?


Hoke is a woman. She has not been edited out of your history books. She simply had no place in history books, no more than I do. What she did was write a book for the small consumer of gold to enable him to refine his own wastes when it was illegal to do so without a federal license. The impact she made on history is irrelevant, at least up to now. Her only other " claim to fame", if you care to consider it as such, is that she was an outspoken socialist. 



> It wasn't my intention to ruffle feathers, Just get a heading somewhere. And some re-direction where otherwise i was just going in circles and reading stuff that didn't apply to what i was seeking. So i was learning nothing i didn't already know about.
> 
> I came here to learn. And also to prevent any round abouts (forums / threads that simply stated, everything is here in this forum, go read it. Instead of provideing the more specific info in the thread posted.) If i had become knowledgeable from reading those, i would not have posted a new thread asking for more info about my chosen method of extraction.
> 
> I will try sweating first, before i go wasteing money on more expensive trial and error, with hazardous chemicals. Which would not only hurt or kill me, but also my family and the surrounding area. Heat i can isolate, insulate, and control, much better then corrosive vapors I can not see, or seal...some of which need speacial materials and equipment to do so safely.


So then, what you've really come here for is validation, not advice? 

Get a new attitude, and get if fast. There will be no more of you disturbing the tranquility of this forum. You have heard from members that know more about gold processing than you can hope to learn in the balance of your lifetime. If what you read doesn't agree with your thoughts, which one do you suppose is out of line? How can you possibly hope to read about a process that is known NOT to work? Why would we go on and on about something that has no interest except in the minds of those that don't have a clue? 



> And even then its not fool proof and from what i've read in the forum, several times, over several posts, could completely destroy both the copper and the gold to the point where "none exist anymore". Which would have made it a complete waste of time, money, and the material used. :|


Nonsense. If in reading this forum, you have managed to draw that conclusion, you have a terrible case of not understanding anything you read. What you need to do is find a new hobby. This one is obviously not suited to your mentality. 

You, sir, are on thin ice with me. I fully expect you to start reading Hoke's book, and not to stop until you understand what she teaches. Any more conversation about your "revolutionary" gold refining process is not going to be met with my approval, and I get down right cranky with those that persist. 

Do you play chess? If so, do you understand the meaning of checkmate?

Harold


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## J burley (Dec 12, 2022)

I found this thinking you would discuss a non acid way to remove gold foils from memory sticks 
Are there chemicals in the home that would accomplish this 
I’ll worry about separating the gold and copper later
Thanks


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## Shark (Dec 12, 2022)

Some search terms to look into……

AP, CuCl2, copper chloride, these three, when doing a search of this forum, will be an overwhelming amount of information to try and consume. They all mean the same thing but produce different results. Also check into copper 2 chloride. Same stuff, different search results. Read some, then ask for what you may not understand.


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## cejohnsonsr1 (Dec 12, 2022)

J burley said:


> I found this thinking you would discuss a non acid way to remove gold foils from memory sticks
> Are there chemicals in the home that would accomplish this
> I’ll worry about separating the gold and copper later
> Thanks


Hydrochloric acid can be produced at just about any hardware store. It’s usually called Muriatic acid and is used to clean driveways and garage floors. The only other thing you need is hydrogen peroxide. The thing you have to understand is that the gold foils are bound to the copper underneath. What you need to do is dissolve enough of the copper to release the gold. That’s what the acid and peroxide does. Once the gold is released, you don’t have to worry about separating it from the copper. All the copper will be in solution. So the answer is no. You’re going to have to use acid. Unless you want to smelt it, but that’s a very expensive, time consuming and labor intensive process that won’t yield pure gold.


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## J burley (Dec 14, 2022)

Thank you 
I will try it 
Do you know the ratios of acid and peroxide?


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## Yggdrasil (Dec 14, 2022)

J burley said:


> Thank you
> I will try it
> Do you know the ratios of acid and peroxide?


You did not say what you are using it for.
But if it is for liberating the gold foils with the so called AP method.
Then you actually do not need any Peroxide at all.
Find some corroded copper and put it in HCl and you are there.
Add a aquarium air pump and bubble air through the solution and you are ready.

As a new member we want you to read C.M. Hokes book on refining jewelers scrap and then study safety and waste treatment.
Everything you need to know is in the forum already so learn to search and find what you need by yourself, ask questions if you do not understand some tings.


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## cejohnsonsr1 (Dec 14, 2022)

J burley said:


> Thank you
> I will try it
> Do you know the ratios of acid and peroxide?


I don’t know the exact ratios, but I used to put about a gallon of Muriatic in a 3 gallon bucket filled with fingers and 3 liters of peroxide to get it started. Then another liter of peroxide every 2 days to freshen it up. A bubbler is good to keep the solution mixed up but you can also just agitate the bucket by hand a few times a day if you don’t have a bubbler. You’ll be told that you don’t have to add peroxide. It’s true. You don’t have to. But peroxide is cheap and not adding it will increase the time to complete from about 7-10 days to possibly 2+ months. Peroxide is cheap.


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## Yggdrasil (Dec 15, 2022)

cejohnsonsr1 said:


> I don’t know the exact ratios, but I used to put about a gallon of Muriatic in a 3 gallon bucket filled with fingers and 3 liters of peroxide to get it started. Then another liter of peroxide every 2 days to freshen it up. A bubbler is good to keep the solution mixed up but you can also just agitate the bucket by hand a few times a day if you don’t have a bubbler. You’ll be told that you don’t have to add peroxide. It’s true. You don’t have to. But peroxide is cheap and not adding it will increase the time to complete from about 7-10 days to possibly 2+ months. Peroxide is cheap.


You have to be very careful adding Peroxide since it may dissolve some of the Gold.
That is why it is better to use an aquarium bubbler for the oxygen need.
Air is even cheaper than Peroxide


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## cejohnsonsr1 (Dec 15, 2022)

Yggdrasil said:


> You have to be very careful adding Peroxide since it may dissolve some of the Gold.
> That is why it is better to use an aquarium bubbler for the oxygen need.
> Air is even cheaper than Peroxide


As long as there’s any copper left, no gold will dissolve due to copper being higher on the list of reactivity. For the amounts we’re discussing there’s really no danger of dissolving gold.


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## Yggdrasil (Dec 16, 2022)

cejohnsonsr1 said:


> As long as there’s any copper left, no gold will dissolve due to copper being higher on the list of reactivity. For the amounts we’re discussing there’s really no danger of dissolving gold.


Well that is not entirely true, it will dissolve but not stay in solution, 
it will cement out which is a bad thing since you have no control on where it cements out.
That can happen on the traces inside the PCB.
This is the reason we advocate the use of air pumps for bubbling air.

And of course the amounts are tiny but why "throw away" any of the little amount of gold they have been struggling to get their hands on.


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## cejohnsonsr1 (Dec 16, 2022)

It would take a lot more peroxide than I recommended to dissolve any gold at all and even then it would only start to dissolve after the copper was almost completely dissolved. Gold is just too much less reactive than copper. And you don’t have to dissolve all the copper. Just enough to break the bond that holds the gold. The bubbler is mostly used to keep the solution moving and, when peroxide is used, to help keep it uniformly mixed in the solution. There’s not really all that much oxygen in air. Far more nitrogen. That’s why it takes so much longer if you don’t use peroxide.


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## Yggdrasil (Dec 17, 2022)

cejohnsonsr1 said:


> It would take a lot more peroxide than I recommended to dissolve any gold at all and even then it would only start to dissolve after the copper was almost completely dissolved. Gold is just too much less reactive than copper. And you don’t have to dissolve all the copper. Just enough to break the bond that holds the gold. The bubbler is mostly used to keep the solution moving and, when peroxide is used, to help keep it uniformly mixed in the solution. There’s not really all that much oxygen in air. Far more nitrogen. That’s why it takes so much longer if you don’t use peroxide.


The bubbler works two folds.
It adds Oxygen (enough oxygen) and keeps things well mixed and stirred.


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## cejohnsonsr1 (Dec 17, 2022)

Yggdrasil said:


> The bubbler works two folds.
> It adds Oxygen (enough oxygen) and keeps things well mixed and stirred.


I guess it depends upon what you consider enough. For me, waiting 2+months for something that already won’t yield enough to be worth the effort is way beyond my threshold. Peroxide is cheap.


Yggdrasil said:


> The bubbler works two folds.
> It adds Oxygen (enough oxygen) and keeps things well mixed and stirred.


It really only keeps the solution moving. Air is only about 20% oxygen and most (nearly all) of that is lost in the bubbles. There’s no appreciable chemical reaction taking place. Peroxide gets distributed throughout the solution and significantly improves the rate of oxidation of the copper.


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## Yggdrasil (Dec 18, 2022)

cejohnsonsr1 said:


> I guess it depends upon what you consider enough. For me, waiting 2+months for something that already won’t yield enough to be worth the effort is way beyond my threshold. Peroxide is cheap.
> 
> It really only keeps the solution moving. Air is only about 20% oxygen and most (nearly all) of that is lost in the bubbles. There’s no appreciable chemical reaction taking place. Peroxide gets distributed throughout the solution and significantly improves the rate of oxidation of the copper.


We are not looking to oxidize the Copper, that is just to form Copper Chloride CuCl2.
The actual etching is done by the Copper Chloride reacting with the Copper and then forming CuCl: 
Cu + CuCl2 → 2 CuCl
Then the CuCl is regenereated to CuCl2 by the oxygen in the liquid.
Short description her : Faster, Safer, and Simpler etching with cupric chloride

Bubbling adds plenty oxygen to keep the Copper Chloride etch active. (Or fish alive  )
You can of course shake the container vigorously a few times a day, but that may be impractical.
The liquid will soak up enough air from the surface to start the process, but it will take even more time.

It is not a fast process, but what you start and let it do its thing, while you do something more productive.


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## cejohnsonsr1 (Dec 19, 2022)

Not a fast process? That’s an understatement. 7-10 days is not a fast process. 2+ months is unreasonable and unacceptably slow. You can type formulas to your heart’s content, but it won’t change the facts. Peroxide is cheap and reduces the time to complete the process by more than 2/3. That’s the proof.


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## Yggdrasil (Dec 19, 2022)

cejohnsonsr1 said:


> Not a fast process? That’s an understatement. 7-10 days is not a fast process. 2+ months is unreasonable and unacceptably slow. You can type formulas to your heart’s content, but it won’t change the facts. Peroxide is cheap and reduces the time to complete the process by more than 2/3. That’s the proof.


It is not even close to cheap where I live, and many others I guess.
So we use the cheap way.


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## Shark (Dec 19, 2022)

Running fingers in AP should take no more than 4 days using only an air bubbler and copper oxide. Three under optimal conditions. If it is taking weeks or more my first suspect would be to little solution. Almost all YouTube videos show people using way too little volume of acids for the amount of material they are running. If I need fingers done quicker then don’t even bother with AP and go straight to AR. I have done gold filled in AP with an aquarium pump in 5 days and 4 using a nebulizer. AP is about volume of solution versus amount of material. We keep seeing questions about ratios of HCl to peroxides when the real question should be how much CuCl2 to material volume. Even if it can do fingers in 4-5 days I consider it slow. AP is for for those items I am in no hurry for. Toss in the material and forget it until I get bored or curious. If I need it quicker than that then I need to be doing something else. 

Also, there are other solutions that do the same job and often quicker. Let’s see a good discussion on ferric chloride. Hot vs cold. And using real numbers skipping the “about” and “maybes”.


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## cejohnsonsr1 (Dec 19, 2022)

Yggdrasil said:


> It is not even close to cheap where I live, and many others I guess.
> So we use the cheap way.


I just looked it up on WalMart. 6x32oz bottles for $5.98. Definitely not expensive.


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## Yggdrasil (Dec 20, 2022)

cejohnsonsr1 said:


> I just looked it up on WalMart. 6x32oz bottles for $5.98. Definitely not expensive.


We do not all live in the US you know.


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## Ag and Au (Dec 20, 2022)

I used too much Peroxide my first time and ended up with a mess; fortunately, the Pros here bailed me out and I recovered the gold.


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## cejohnsonsr1 (Dec 20, 2022)

Yggdrasil said:


> We do not all live in the US you know.


Hard to believe that a product as ubiquitous as hydrogen peroxide could be very expensive. At least in any developed country.


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## Yggdrasil (Dec 21, 2022)

cejohnsonsr1 said:


> Hard to believe that a product as ubiquitous as hydrogen peroxide could be very expensive. At least in any developed country.


I can buy 49% in 25 liter cans for 160 USD.
I haven’t even seen 3% 
The problem is not that it is expensive or hard to produce, it is considered a precursor in high concentration and in low concentration bleach do a better job.
And for our use, an air pump is even cheaper, especially in the long run.


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## cejohnsonsr1 (Dec 21, 2022)

Yggdrasil said:


> I can buy 49% in 25 liter cans for 160 USD.
> I haven’t even seen 3%
> The problem is not that it is expensive or hard to produce, it is considered a precursor in high concentration and in low concentration bleach do a better job.
> And for our use, an air pump is even cheaper, especially in the long run.


That price scales about the same, but you wouldn’t need 25 liters and 49% would probably be way past the point of diminishing returns. Are you telling me you don’t have a neighborhood pharmacy or grocery store that sells basic 1st aid supplies? 3% peroxide should be available almost any place you can buy bandaids.


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## Yggdrasil (Dec 22, 2022)

cejohnsonsr1 said:


> That price scales about the same, but you wouldn’t need 25 liters and 49% would probably be way past the point of diminishing returns. Are you telling me you don’t have a neighborhood pharmacy or grocery store that sells basic 1st aid supplies? 3% peroxide should be available almost any place you can buy bandaids.


That is why I haven't bought it in bulk, I found a 100ml bottle of 10% at a pharmacy and they demanded 15 USD so I dropped it.
We use different substances here, mostly something called Chlorhexidine.
There may be at hairsaloons, but frankly I haven't checked them, since I don't need it.


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## kurtak (Dec 22, 2022)

cejohnsonsr1 said:


> I don’t know the exact ratios, but I used to put about a gallon of Muriatic in a 3 gallon bucket filled with fingers and 3 liters of peroxide to get it started. Then another liter of peroxide every 2 days to freshen it up


I am sorry but using that much peroxide (about a gallon) mixed with a gallon of HCl will most certainly dissolve some gold - even with the peroxide at only 3 percent


cejohnsonsr1 said:


> As long as there’s any copper left, no gold will dissolve due to copper being higher on the list of reactivity. For the amounts we’re discussing there’s really no danger of dissolving gold.


I am sorry but that is not how the reactive series works

It is NOT *selective* to just one metal because that one metal happens to be higher in the series

If you have more then one metal involved - & all of those metal will react with a given acid (or oxidizer) the acid/oxidizer WILL react with ALL of those metals

It's just that the acid/oxidizer will react more with the metals higher in the series & less with the metals low in the series

Because the acid/oxidizer reacts with all the metals the higher reactive metal will cause whatever lower reactive metal that is dissolving to cement back out - that is called a redox reaction

With that much peroxide you are *more then likely* dissolving at least *some* gold - you just don't know it because gold being so low in the series the oxidizer is working on the gold - *just much less* then on the copper - so it's not dissolving all the gold --- the small amount of gold that is dissolving is then cementing out on the copper & again you just don't know it because the amount of gold you are dissolving is small in the first place under these conditions

Kurt


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## cejohnsonsr1 (Dec 23, 2022)

Yggdrasil said:


> That is why I haven't bought it in bulk, I found a 100ml bottle of 10% at a pharmacy and they demanded 15 USD so I dropped it.
> We use different substances here, mostly something called Chlorhexidine.
> There may be at hairsaloons, but frankly I haven't checked them, since I don't need it.


$15 for 100ml? I wouldn’t pay that. Still can’t understand why something like peroxide would be so expensive. What country?


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## cejohnsonsr1 (Dec 23, 2022)

kurtak said:


> I am sorry but using that much peroxide (about a gallon) mixed with a gallon of HCl will most certainly dissolve some gold - even with the peroxide at only 3 percent
> 
> I am sorry but that is not how the reactive series works
> 
> ...


Maybe in theory. In practice I’ve never put a single atom of gold into solution with this method. It performs just as I described and took 7-10 days to complete the process.


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## Yggdrasil (Dec 23, 2022)

cejohnsonsr1 said:


> $15 for 100ml? I wouldn’t pay that. Still can’t understand why something like peroxide would be so expensive. What country?


It is beside the point. 
The price is used as a deterrent for the ones (my guess) that can't source it by industrial/professional routes.
This is in Norway, but i guess it is more or less the same around here.
The point is, that for most it is cheaper to use air bubbling and the risk of inadvertently dissolving some of the Gold disappear.


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## kurtak (Dec 23, 2022)

cejohnsonsr1 said:


> Maybe in theory. In practice I’ve *never put a single atom of gold into solution* with this method. It performs just as I described and took 7-10 days to complete the process.


Per the bold print - what make you so sure about that

Kurt


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## Yggdrasil (Dec 23, 2022)

kurtak said:


> Per the bold print - what make you so sure about that
> 
> Kurt


I kind of agree if we are following the science, as we should strive to do
Even washing with soap will dislodge single atoms and as such put them “into” solution in a 0 valence state as colloids. 
But since there is an oxidiser in play, there will most certainly be measurable quantities of Gold dissolved. 

Anyway it may be hard to get to them and the amounts will be miniscule since they for the most part will cement out on what ever base metals is available at any given time.
So I agree with Kurt here


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## kurtak (Dec 23, 2022)

cejohnsonsr1 said:


> Maybe in theory.


There is no theory about it - it is a scientific fact (what I posted yesterday)

Acids/oxidizers don't have a mind of their own where they "decide" - I am going to work on this metal - but not on this other metal

Rather - they work - more - or less - on the metal(s) according to the metal(s) place in the series

If I put a copper coin a silver coin & a palladium coin in a beaker with nitric acid the acid is not going to "decide" to work on just the copper because it is the most reactive of the 3 metals

Rather - it is going to work mostly on the copper - also on the silver but less then on the copper - also on the palladium but less then on the silver &/or copper

So - if HCl + H2O2 will dissolve gold - it will dissolve gold whether there is copper in with the gold - or not

Kurt


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## Shark (Dec 23, 2022)

If we place fingers in CuCl2 (AP) it eats the copper out from under the gold layer. If enough oxygen is introduced it starts working on the other metals, gold on the fingers. It will cement the gold back out and and leave this as powders in the solution along with the foils. Excess oxidizer will leave a larger amount of powders than when using an air bubbler such as an aquarium pump because it adds a lower amount of oxygen than an oxidizer, such as peroxide, but provides an aggressive amount of stirring action to the solution. If we use filter papers to capture the foils from AP then the powders are a minimal loss of gold. If we strain the foils through a coarse filter such as a colander then the loss becomes more noticeable. Proper clean up of our waste stream will return these losses but then we don’t know how much came from which batch. The real down side to using large volumes of peroxide is the increased volume of waste for the smaller volume of gold being processed.

All that being said in the simplest terms makes sense to many who aren’t good with the science of what we do, but this does not discount the science of it. Knowing the science can greatly aid when things go wrong and we are trying to fix the problem. I believe that when I want to learn something I am better served by knowing as much as possible. I struggle with the scientific terms at times due to some memory issues and tend to use over simple terms. I can understand a fair bit of the formulas and read them fairly well. I struggle hard to get it back out of my head and back into writing, hence the simple wording.

We need an open mind to learn, if we close our mind we don’t loose the ability to learn we shut it off. Turning off our own ability to learn is much worse than loosing that ability.


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## cejohnsonsr1 (Dec 23, 2022)

kurtak said:


> Per the bold print - what make you so sure about that
> 
> Kurt


The stannous test. No reaction. No gold in solution.


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## cejohnsonsr1 (Dec 23, 2022)

kurtak said:


> There is no theory about it - it is a scientific fact (what I posted yesterday)
> 
> Acids/oxidizers don't have a mind of their own where they "decide" - I am going to work on this metal - but not on this other metal
> 
> ...


The point is that we’re not using nitric and we’re not using enough peroxide to dissolve gold even if it were the only metal in question. It will, however, accelerate the process of dissolving enough of the copper to release the gold.


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## kurtak (Dec 24, 2022)

cejohnsonsr1 said:


> The stannous test. No reaction. No gold in solution.


That is because the gold that is being dissolved by the HCL + H2O2 is being cemented back out of the solution by the copper (the redox reaction I mentioned the other day)

Redox is a reaction where both oxidation & reduction take place *at the same time*

Redox happens when two (or more) metals can be oxidized by the same oxidize - but one metal is more reactive then the other metal 

It happens because though the oxidizer can work at dissolving more then one metal - *at the same time* --- the more reactive metal (copper) will cause the less reactive metal (gold) to be reduced - *just as fast* as that less reactive metal is being oxidized 

in other words - due to the redox reaction - the copper is *preventing the gold from staying in solution* - therefore - because the gold is being reduced *as fast* as it is being oxidized - it (the gold) will not show up with a stannous test because the gold is not staying in solution due to copper cementing the gold (redox) 

The cemented gold is going to be ultra fine gold particles & likely washed away when washing the chem out of the (remaining) gold foils

Kurt


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## cejohnsonsr1 (Dec 25, 2022)

kurtak said:


> That is because the gold that is being dissolved by the HCL + H2O2 is being cemented back out of the solution by the copper (the redox reaction I mentioned the other day)
> 
> Redox is a reaction where both oxidation & reduction take place *at the same time*
> 
> ...


Hence my reference to the reactivity of metals previously. If any gold is being dissolved, and I don’t concede that there is, then it isn’t in solution and, equally important, it’s not in the filter. Since that’s the only 2 places it could be, it hasn’t dissolved. And that is the difference between theory and practical application.


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## Yggdrasil (Dec 25, 2022)

cejohnsonsr1 said:


> Hence my reference to the reactivity of metals previously. If any gold is being dissolved, and I don’t concede that there is, then it isn’t in solution and, equally important, it’s not in the filter. Since that’s the only 2 places it could be, it hasn’t dissolved. And that is the difference between theory and practical application.


It will dissolve and then cement out, where it cements out is out of our control.
It will not be much, but I see no reason in throwing it away anyway.


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## cejohnsonsr1 (Dec 25, 2022)

Yggdrasil said:


> It will dissolve and then cement out, where it cements out is out of our control.
> It will not be much, but I see no reason in throwing it away anyway.


My point was that if it’s not in solution and not in the filter then it didn’t dissolve. 

As an aside, I got curious about the price of peroxide in Norway so I did a little research. When you 1st told me how expensive it was I was a little skeptical. Now I’m just shocked and I still don’t understand why it should be so expensive there. What makes something so common and cheap here so expensive there? I don’t get it.


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## Yggdrasil (Dec 26, 2022)

cejohnsonsr1 said:


> My point was that if it’s not in solution and not in the filter then it didn’t dissolve.
> 
> As an aside, I got curious about the price of peroxide in Norway so I did a little research. When you 1st told me how expensive it was I was a little skeptical. Now I’m just shocked and I still don’t understand why it should be so expensive there. What makes something so common and cheap here so expensive there? I don’t get it.


I tend to disagree, it just means it don't stay in solution.
As a business you can get it relatively "cheap", not as a private citizen.


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## cejohnsonsr1 (Dec 26, 2022)

Yggdrasil said:


> I tend to disagree, it just means it don't stay in solution.
> As a business you can get it relatively "cheap", not as a private citizen.


I still don’t understand why peroxide should be so expensive. But to the point, if gold (or any other metal, goes into solution, it must precipitate. So if it’s not in solution and there is no precipitant, then it never dissolved. This ain’t magic. It doesn’t reincorporate back into the foils from which it came. There has to be either gold in solution or a precipitant. If there is neither, then it never dissolved.


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## Yggdrasil (Dec 27, 2022)

cejohnsonsr1 said:


> I still don’t understand why peroxide should be so expensive. But to the point, if gold (or any other metal, goes into solution, it must precipitate. So if it’s not in solution and there is no precipitant, then it never dissolved. This ain’t magic. It doesn’t reincorporate back into the foils from which it came. There has to be either gold in solution or a precipitant. If there is neither, then it never dissolved.


No but there are plenty space inside the traces on the PCB and since it is low amounts/concentration what ever precipitates will be very fine, probably too fine for most filters.
You have found a way that suits you and are happy with the results.


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## Yggdrasil (Dec 27, 2022)

cejohnsonsr1 said:


> I still don’t understand why peroxide should be so expensive. But to the point, if gold (or any other metal, goes into solution, it must precipitate. So if it’s not in solution and there is no precipitant, then it never dissolved. This ain’t magic. It doesn’t reincorporate back into the foils from which it came. There has to be either gold in solution or a precipitant. If there is neither, then it never dissolved.


Our government has found that adding ludicrous amount of taxes on products that are legal but they don't like is an effective way of controlling the market.
Tobacco, Alcohol, gasoline and so on.


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## cejohnsonsr1 (Dec 28, 2022)

Yggdrasil said:


> Our government has found that adding ludicrous amount of taxes on products that are legal but they don't like is an effective way of controlling the market.
> Tobacco, Alcohol, gasoline and so on.


Well you have my sympathy. I guess I really do understand after all. I hope you had a Merry Christmas and I wish you a Happy New Year.


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## cejohnsonsr1 (Dec 28, 2022)

Yggdrasil said:


> No but there are plenty space inside the traces on the PCB and since it is low amounts/concentration what ever precipitates will be very fine, probably too fine for most filters.
> You have found a way that suits you and are happy with the results.


I didn’t use whole boards. I used closely trimmed fingers. If any metal can’t be detected by any means, it isn’t there.


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## BobK (Dec 31, 2022)

cejohnsonsr1 said:


> Hard to believe that a product as ubiquitous as hydrogen peroxide could be very expensive. At least in any developed count


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## galenrog (Dec 31, 2022)

Prices and availability of what Americans would consider household chemicals vary widely in the world. In much of the EU there are several layers of taxes that most there are not even aware of. The VAT is just the most visible. Most of these taxes are designed to do as Yggdrasil says: control access through price. 

Time for more coffee.


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## cejohnsonsr1 (Jan 1, 2023)

galenrog said:


> Prices and availability of what Americans would consider household chemicals vary widely in the world. In much of the EU there are several layers of taxes that most there are not even aware of. The VAT is just the most visible. Most of these taxes are designed to do as Yggdrasil says: control access through price.
> 
> Time for more coffee.


Yeah. When he put it in those terms I understood perfectly.


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