# Question about processing cell phones



## Bluebloomer (Aug 9, 2014)

Hi all, perhaps this question has been asked before, but I couldn't find it in the search results.. 
My question is; would it be a good or bad idea to soak cellphone boards in a nitric acid solution to dissolve base metals and silver, then cement the silver out of the nitric acid before proceeding with an A/P bath to recover the gold?
My first idea was to dissolve the base metals with sodium hydroxite, but that will cling the dissolved base metals on the gold making it harder to recover the gold, so that's a no go. 

SO I thought, why not first extract the silver and base metals with nitric acid, before trying to get to gold?
The nitric acid will be contaminated with different metals, but if that solution would be filtered and then cement the silver out with copper (I have a 1 inch round solid piece of red copper) then the cellphone board will be largely free of base metals making it easier to use the A/P ?

It's just a thought, perhaps I am missing a crucial chemical reaction, but it's sometimes very hard to read and understand all the English explations and I have to google a lot words as I am just a simple Dutch guy.
I'm not trying to find shortcuts, and I'm not pretending to know it beter.. 
Thanks


----------



## solar_plasma (Aug 9, 2014)

Tin and HNO3 make an unnecessary mess, that is hard to deal with. It will create metastannic acid, which will trap the gold foils and powders and will add extra chemical steps to the process, while each chemical step raises the amount of waste, effort and costs). Metastannic can only be dissolved in large excess of hot alkali hydroxide or has to be decomposed by heat to an oxide and then dissolved by HCl (see also: http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=37&t=15324)

The propper way to go is in short terms: remove all parts from the board, clean the boards from tin (fx. HCl), going for the gold foils by copper II chloride etching.

The leftover components have to be processed separately:

gold plated copper parts: sulfuric cell (fast) or copper II chloride (slow)
mlcc: different methods available, all are about leaching base metals first, then palladium, then silver from leftover solids
ICs and ccd: incinerating/milling/gravity separation/straight AR
resonators: straight AR

This is just an overview. Each process has to be learned first, which will take about 100 hours of reading, - just to give an impression of effort. You need to have read Hoke and followed the forum guide first. Most important is to read about safety and how to deal safely and responsible with highly toxic waste. You will have to re-read a lot of it more than one time and still be confused sometimes. Then you will have to and are welcome to ask.

As you can see, if you don't get them for free, it is completely uneconomic. Though it is almost impossible to give valid yield numbers, you might estimate 1g gold from 100 old (no touchscreens) cell phones. That won't be too far off.

Good luck.


----------



## nickvc (Aug 9, 2014)

Another problem you will encounter using ntric is that any Pd will also go into solution.


----------



## solar_plasma (Aug 9, 2014)

Which reminds me to find time to make some metastannic experiments, since I never encountered any myself. :lol: 

Though I don't expect much useful, it might be another tool for workarounds for a some strange settings, I only have some diffuse thoughts about. For example, parting Sn/Pb/Ag/Sb/Cu-solder alloys, but I have to read and think some month about it. There are some Sb compounds, that seem scary to me and I want to be sure, not to produce them. One thing for sure, it would not be profitable.


----------



## Bluebloomer (Aug 9, 2014)

Solar, thank you for the clarification. I have downloaded a bunch of books form this forum aswel as other boards, but reading it and understanding it are 2 different things, lol. But I understand what you are saying and why it is a bad idea to do it. 
The sulfuric cell scares me a little, not as much as nitric acid though, but perhaps when I get more experienced the sulfuric cell might be worth the efford.

I was under the impression however, that a dilluted nitric acid solution would dissolve the base metals but would leave the gold intact because it would not eat the copper but it would dissolve the silver. I guess I misunderstood that process, or it was also a bit of misinformation from the internet ?

Copper ii chloride is the way to go I understand, those chemicals are ordered. Dillute nitric acide is also the way to cement the silver with copper, and I read it's optional to percipitate the Pd, but if you do not get the palladium out of the dillute HNO3 will it interfere with the silver percipitation ? I have about 3 Oz of mlcc's (monolithic caps) and most youtube clips are only about recovering the Pd from those, but I only want the silver. 
The 3 pounds of IC chips will indeed be incinerated once I get to at least double the 3 lbs. Then washing the ashes.. The resonators (aka oscillators?) in the HCL is new to me, so thanks for that tip, cound't find much info about crystals or oscillators haha.


In no way I'm trying to re-invent the wheel, just trying to understand why certain steps are being take, so I know why certain should NOT be taken .. And as for yields.. I don't bother to focus on a number, because I know as a newbie I'm bound to make mistakes that will cost yield.. So, the numbers, who cares. It's a fun and educative hobby, and when done right it might bring you a few bucks but in no way it will make me rich...

So thanks a lot for all the input, and I will read a lot more than I already do..


----------



## solar_plasma (Aug 9, 2014)

Too many easy questions, which once answered, will lead to 5 new questions :lol: read this thread twice and spend more time re-reading, what you already have read. I believe, you should not start with the chemicals, yet. Take the time it needs FIRST to understand the processes to the bone.


----------



## butcher (Aug 11, 2014)

Bluebloomer,

There is a lot to learn in recovery and refining of metals, a very good place to begin learning is with Hokes book, study of this book will introduce you to the basic principles of recovery and refining precious metals, doing the experiments in the book will help you understand many of the chemical reactions, and learning how to use test solutions which will tell you where values are or are not.

Another way to get a better understanding and experience, is by studying the forum and working with simple materials to begin with, like recovery of gold foils from memory fingers, and then the process of refining them, working with these helps because you are only dealing with mostly two metals (not counting nickel) gold and copper (if you do this properly and keep tin or lead from solder out of the process with good mechanical pretreatment of the material memory fingers, close cutting them from the circuit board to avoid the solder), you can also use the gold and its solutions to do some of the tests, or experiments, you learned from Hokes book, to get a better understanding of the reactions...

Another example would be working with sterling silver to recover the silver, you can use the sterling to recover silver in a couple of different forms, to get better acquainted with the different processes like cementing silver with copper from a silver/copper nitrate solution, and doing some experiments recovering the silver as a silver chloride, and using the different methods to convert the silver chloride back to elemental silver, NaOH/Karo syrup, aluminum HCl, and iron and the dilute sulfuric acid methods, to get better acquainted with the chemical reactions of silver.

Working with simpler solutions can help you get a better understanding, seeing what happens with just one or two metals in a chemical reaction, will help you have a better understanding of what to expect when you have a half dozen metals in solution... 

In many ways recovery and refining of karat gold, can help you have a better understanding of what to expect when you try and recover or refine gold from a more complex material like electronic scrap.

Many people try to learn, with a material like electronic scrap, picking a scrap material that will be loaded with problems, and is hard to recover values from, to learn on, thinking this whole thing is just some simple process, all they have to do is follow the steps in a video, or from some step by step process, they do not spend the time to learn the basics, or to gain an understanding of the principles involved, they do not have any clue of the chemistry involved, or how different metals react chemically with acids or each other.
Basically they are going in blind making a big dangerous mess, then they spend most of their time trying to recover from problems, wasting their time losing values, and trying to learn to recover some of their values from the messes they make. 
When if they spent half that amount of time with study first, they would have long ago have melted their first gold button of purified gold, and been well on their way to understanding more of the chemistry of recovery and refining of precious metals...

Spend time learning the testing processes...

Spend time learning the safety aspects, and dealing with waste solutions...

As you gain an understanding of the principles with working with the more simple materials, it will make it easier to understand, when you begin to learn or work with the more complex solutions or trying to recover values from the more complex scrap materials.

This is actually fairly complex science, that will take quite a bit of time to learn, it will make it easier to learn if you approach it, and your study in a scientific method, learning the basics first, the safety, and how to deal with waste, plan your lessons to learn the basics, use simple experiments and work your way up to the more complex.

The more time you spend in study the faster you will be able to understand, the more gold you will recover from doing it properly with an understanding of what you are doing and how to do it, if there is a problem you will have the understanding to troubleshoot the problem and correct it, you will be able to decide what method or approach would be best to tackle different types of scrap, and how to recover and refine the values from them...

Jumping in to the chemistry before you spend time in study, you will be wasting your time and money, which will lead to you losing your values, and leaving you spending many hours with many different problems, with you standing there scratching your head wondering where all of the values you dissolved went, and asking dumb questions of how do I get my gold back out of this mess I made, all the while putting yourself and others in danger because you do not understand the dangers involved with this dangerous chemistry you are trying to do, to get a little bit of gold form some toxic hazardous waste solution, or mess you have made.

Learn to crawl before you learn to walk, and soon you will be running.

It will take time but it is worth it in the long run.

This is not something you will learn overnight; in fact if you spent three lifetimes I doubt you would still be able learn it all.

The education you will gain is more precious than the gold you will recover.


----------



## Wingedcloud (May 3, 2016)

solar_plasma said:


> Tin and HNO3 make an unnecessary mess, that is hard to deal with. It will create metastannic acid, which will trap the gold foils and powders and will add extra chemical steps to the process, while each chemical step raises the amount of waste, effort and costs). Metastannic can only be dissolved in large excess of hot alkali hydroxide or has to be decomposed by heat to an oxide and then dissolved by HCl (see also: http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=37&t=15324)
> 
> The propper way to go is in short terms: remove all parts from the board, clean the boards from tin (fx. HCl), going for the gold foils by copper II chloride etching.
> 
> ...


Solar,

I'm currently studying/looking for a process to treat cellphone boards, cleaned from any components. I am thinking about using the AP method, as I have used it before with fingers from RAM memories. However, after I read your reply in this thread, I have a question:

When you say "gold foils" i think about the places where the buttons from the keypad make contact. But when you atalk about "gold plated copper" what do you mean? Are you refering to those parts of the board that contain gold plating?
If so, is it correct to run the boards in HCl, to remove tin, followed by AP, to catch foils, ending in sulfuric cell, to get the plating?

Hope you can answer this.

Kind regards,
Winged


----------



## jason_recliner (May 7, 2016)

Wingedcloud said:


> solar_plasma said:
> 
> 
> > The propper way to go is in short terms: remove all parts from the board, clean the boards from tin (fx. HCl), going for the gold foils by copper II chloride etching.
> ...



Yes, but no. You are correct in that the foils are the gold plated tracks on the board. But Björn said "gold plated copper parts", such as pins and the like. These solid plated items may be sent to a sulfuric cell. That is a separate process to the boards.

The rest of the depopulated board is much like your memory fingers, in copper (ii) chloride. If you remove tin and lead solder first with HCl, you will not befoul your leach. It's always good to rid yourself of these things first whenever possible.

That said, it also depends on how much material one is handling, and the relative effort to reward. There are some who throw whole boards into "AP". That's fine as long as you recognise that you will not have 'clean' copper ii chloride, and that you cannot easily reclaim clean copper by cementing with iron, as you will also drop tin and lead. There are workarounds for this, but removing tin first is a pretty simple task.


----------

