# Processing mobile phone parts



## Zolotov (Mar 18, 2017)

Hi,
to do my first gold refining test I want to process mobile phone parts (didn't get any fingers). After disassembling around 200 phones I got this pile 


After sorting the pile I got these items:

2.7g of gold plated flakes (plated on steel I guess, because they can be attracted with a magnet):



179.2g of gold plated cables (with ferrous compounds in them)



35.5g of gold plated wires embedded in plastic




and 239.6g of random items with gold plated parts



From what I have learned so far, since my scrap is almost all ferrous I have to use aqua regia. But before AR I can filter out the stuff with 2 reactions:
1) Nitric acid. (AP)
or
2) Oxidizing. (Burning)

Which one is the best for this stuff?
Since there is plastics in cables and connectors, burning seems to be the right thing, but I am in doubt what to choose, don't want to make a mistake.

Will appreciate your comments very much.


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## kernels (Mar 18, 2017)

Pretty much everything in those pictures will be simultaneously difficult and leave you with so little gold that you will not know whether or not it had been dropped from solution.

Did you already depopulate the boards and process the chips ? That is where the 'easy' gold will be.


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## Zolotov (Mar 18, 2017)

kernels said:


> Did you already depopulate the boards and process the chips ? That is where the 'easy' gold will be.


Yes, I depopulated with sand bath, 2kg of these boards, and this is what I have:

1,302.2g - depopulated PCBs without electronic components
108.3g - the chips (integrated circuits)
213.1g - aluminum
87.6g - metalic (gold plated) connectors
51.5g - plastic (gold plated) connectors
22.7g - cameras
99.6g - tiny items (impossible to sort): tny ICs , small resistors, capacitors , etc.
115g - lost material or ferrous junk

I am going to process the chips tomorrow. 
I do not understand well why are you saying gold will not be visible. If I use nitric acid gold plated connectors will be visible. I can see them right now. Then, after I filter the black liquid processing with aqua regia should be much easier because all the plastic was removed. The nitric acid is just to get rid of the plastic. Right or wrong?


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## kernels (Mar 19, 2017)

Trying to get rid of plastic using Nitric acid is a great way to create a big mess. You can use nitric acid on gold plated copper connector pins, but usually you will use a lot of acid to get rid of a lot of copper for very little gold.

From the 100g of chips, you can expect up to maximum 0.5g of gold when you get experience with processing, for the first time, usually people do not get such a good yield.

Some of the PCBs will appear to be gold plated, you won't believe me, but there is almost no gold there, hardly worth the acid and not worth the effort to process. 

When I say that the gold will not be visible, I mean that when you dissolve the gold, then precipitate the gold (refine the gold), there will be such a small amount of gold in all those connectors that the gold will settle as a fine dusting on the bottom of the beaker.


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## patnor1011 (Mar 19, 2017)

Too much plastic there, it may get affected by nitric. You need to reduce plastic to almost zero either by sorting or incinerating(with a risk of values being blown off if not done correctly).


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## Zolotov (Mar 19, 2017)

kernels said:


> From the 100g of chips, you can expect up to maximum 0.5g of gold when you get experience with processing, for the first time, usually people do not get such a good yield.
> .


Thanks for the input. 
0.5 g of gold is very low, I am puzzled.
Lets say I processed it and got the 0.5g but I still wouldn't understand where the gold leak is.
This is my math:
One ton of mobile phones produces 300g of gold
One ton of mobile phones can contain maximum of 17,000 phones, minimum 10,000, suppose we have 17,000
Gold plated items (cables, plastics, cameras, etc) contain microscopic amount of gold per kg, so we consider it 0. Then all the gold must be located on the board in components.
1kg of mobile phones will contain 0.3 grams of gold (300/1000) and 17 mobile phone boards (17,000/1000) . (according to reported data)
Since I have already stripped off all the plastic parts, my kg of scrap contains only boards , I have counted them, and I have 120 boards in those 2kg, which means there is around 60 mobile phone boards per kg.
So, at least I must produce 3.52 (60/17) times more gold than the reported statistics, or exactly 1 gram of gold per kg (3.52 x 0.3g). If I would process 2kg, the yield must be 2 grams, but I got only 100g of chips, and as you say, there is not enough gold there to complete 2 grams, 1.5g is missing.
This is why I scratch my head and say, where is the gold leak ???? An enormous black hole in statistics , I would say


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## patnor1011 (Mar 19, 2017)

I cant see any IC chip in your pictures. Where are they? Most of gold will be in them.
All like these I marked in this picture:


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## kernels (Mar 19, 2017)

If I do the math as per my physics textbook, then my car should have equal grip using very skinny tyres as it does when I have very wide tyres fitted. (Because friction is not dependent on contact area)

The reality is that there are losses in every process you will do and the smaller your input source is, the more the losses will be proportionally. I would personally not bother at this stage to process 100g of BGA chips by themselves, you are welcome to try it as an experiment, it is the only way you will really learn.

300g of gold per 1000kg of mobile phones seems very high to me, this makes raw cellphones 3 times better to process than some ICs. If you said that that is only for cellphone boards, then it is starting to sound more reasonable.

Remember when you read those statistics about xxg per ton of cellphones, the people doing that recovery used very different processes from what you will likely be using. As a home refiner, you will only be recovering the easy gold, the big companies are able to scale up and recover gold from every part.


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## patnor1011 (Mar 19, 2017)

kernels said:


> If I do the math as per my physics textbook, then my car should have equal grip using very skinny tyres as it does when I have very wide tyres fitted. (Because friction is not dependent on contact area)
> 
> The reality is that there are losses in every process you will do and the smaller your input source is, the more the losses will be proportionally. I would personally not bother at this stage to process 100g of BGA chips by themselves, you are welcome to try it as an experiment, it is the only way you will really learn.
> 
> ...



This:
http://en.community.dell.com/dell-blogs/direct2dell/b/direct2dell/archive/2013/03/20/how-much-gold-is-in-smartphones-and-computers

o learn more about gold and how it is removed from discarded devices, I spoke to Sean Magann, vice president of sales and marketing for Sims Recycling Solutions—North America, a division of the global re-use and recycling firm Sims Metal Management.

How much gold is in a smartphone?

Magann: In very rough numbers, there are 10 troy ounces of gold (or about three-fifths of a pound) per ton of smartphones. Ten thousand phones weigh one ton. [With gold selling for about $1,580 per ounce, that would yield $15,800.]

How about a laptop?

Magann: Two hundred laptops would yield five troy ounces of gold.

How much is in an average desktop?

Magann: A PC circuit board, where the gold is, weighs about a pound. If you had a ton of those boards, you should have 5 troy ounces of gold.


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## kernels (Mar 19, 2017)

OK, so that is interesting, 300g in a ton of phones, 10k phones in a ton of phones, that means 300g in 10k phones. That means 0.03g per phone. That seems much more reasonable to me. 

0.03g I would expect from 6g of good high-yield ICs, which seems reasonable for the number of ICs in a smartphone. So yes, it looks like most of the gold in a phone does come from the ICs.


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## Zolotov (Mar 19, 2017)

patnor1011 said:


> I cant see any IC chip in your pictures. Where are they? Most of gold will be in them.



this is the material I have got from the 2kg of the boards from depopulating them:

108.3 grams of ICs:



201 grams of aluminum:



87.6 grams of metallic connectors:



51.5 grams of plastic connectors:



22.7 grams of cameras:


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## Zolotov (Mar 19, 2017)

and 99.6 grams of tiny material that went off the board (small ICs, resistors, capacitors, etc)





all this material is contaminated with sand tough


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## Zolotov (Mar 19, 2017)

kernels said:


> The reality is that there are losses in every process you will do and the smaller your input source is, the more the losses will be proportionally. I would personally not bother at this stage to process 100g of BGA chips by themselves, you are welcome to try it as an experiment, it is the only way you will really learn.


Yes, this is for learning. Becuase I have about 25kg of these boards right now, but I am afraid to screw it.



kernels said:


> 300g of gold per 1000kg of mobile phones seems very high to me, this makes raw cellphones 3 times better to process than some ICs. If you said that that is only for cellphone boards, then it is starting to sound more reasonable.



I got this data from here on 'Data' section, this is the thread:
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=33&t=20851

And I am ok with the losses, I just want to know where I am losing it and how much.
I was thinking to put the boards as they come (no preprocessing) into aqua regia (a sample of 1kg) and try to get the gold out of it. This way I won't lose anything since everything will be dissolved. I just have to extract aluminum, iron, copper, tin, lead individually until gold is left and then precipitate it with metabisullfite. Not sure how I am going to do this, but this video of aqua regia plant inspired me:
https://www.youtube.com/watch?v=ahVXhxDwmNg
if some guy can, then I also can do it, even if I have to try dozens of times.


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## Zolotov (Mar 19, 2017)

I just turned off the incineration process. I processed the chips together with the small items (resistors, capacitors and other tiny stuff) and I have some substance of yellow color at the top. Is this some dangerous compound? Or maybe it is sulfur? I didn't see this yellow stuff on youtube videos, probably I did something wrong. I had it for 1 hour burning, at the beginning there was some small smoke, but after about 40 minutes smoke totally disappeared. Probably I shouldn't mix the chips with the small items.
Here is the pic:


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## anachronism (Mar 19, 2017)

Can we inject a bit of reality here?

So Sims say I could have 300g per tonne of mobile phones That's based upon modern refinery techniques where every scrap of gold is collected. Your average guy at home as nowhere near the same tech available. This whole exercise, whilst interesting will be something that you look back on and say "never again, I could have sold them and bought loads of easily recoverable product with the proceeds."


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## kernels (Mar 19, 2017)

anachronism said:


> Can we inject a bit of reality here?
> 
> So Sims say I could have 300g per tonne of mobile phones That's based upon modern refinery techniques where every scrap of gold is collected. Your average guy at home as nowhere near the same tech available. This whole exercise, whilst interesting will be something that you look back on and say "never again, I could have sold them and bought loads of easily recoverable product with the proceeds."



Yep,I have tried to say the same thing in a few different ways in this thread. It is quite difficult to explain to someone new that there is a big difference between theoretical recovery and real-world-at-home recovery.


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## Topher_osAUrus (Mar 19, 2017)

Why did you mix them?


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## Zolotov (Mar 20, 2017)

Topher_osAUrus said:


> Why did you mix them?


because they contain gold. those chips are black, they are just of a smaller size. capacitors also contain gold. and any ferrous stuff will go out with a magnet, so i thought "why not?".


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## Zolotov (Mar 20, 2017)

anachronism said:


> Can we inject a bit of reality here?
> 
> So Sims say I could have 300g per tonne of mobile phones That's based upon modern refinery techniques where every scrap of gold is collected. Your average guy at home as nowhere near the same tech available. This whole exercise, whilst interesting will be something that you look back on and say "never again, I could have sold them and bought loads of easily recoverable product with the proceeds."



You can collect every scrap of gold too. What tech do they have? The reactions work the same at big scale or small scale, so I don't see why an average guy at home can't do the same. Or, do you mean that they are using patented processes that we don't even know about? Then , that's different. But if they do it with aqua regia, then being big or small guy doesn't matter. Scale affects the volume only. So if I have 1kg of mobile phones, I should get 0.3 grams of gold


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## Topher_osAUrus (Mar 20, 2017)

Yeah. I understand that train of thought.(..i once had it, sometimes still do...)
But, I know if I had some 18k green gold, 18k red gold, and 18k yellow gold, I wouldnt just throw them all into AR because "they all have gold". 

Each type of feedstock requires it's own process. Sure, sometimes they get to a "point" in each of their processes where they can all get thrown in together. But, you must know each of their own idiosyncracies first. That way you aren't creating more work for one of the batches, by throwing it in with something that needs 3 more steps to get where it needs to be, to be "properly" mixed with the other lots.

I know you are working with escrap, and not karat gold, but the same principles hold true.


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## shmandi (Mar 20, 2017)

Zolotov said:


> You can collect every scrap of gold too. What tech do they have? The reactions work the same at big scale or small scale, so I don't see why an average guy at home can't do the same. Or, do you mean that they are using patented processes that we don't even know about? Then , that's different. But if they do it with aqua regia, then being big or small guy doesn't matter. Scale affects the volume only. So if I have 1kg of mobile phones, I should get 0.3 grams of gold



You still have much to learn. No, you cannot do the same at home. In theory you could but for what cost... 
They mostly recover PMs in copper cells. AR is used for refining.


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## kernels (Mar 20, 2017)

Zolotov said:


> anachronism said:
> 
> 
> > Can we inject a bit of reality here?
> ...



Good luck, looking forward to hearing your results.


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## Zolotov (Mar 20, 2017)

shmandi said:


> No, you cannot do the same at home. In theory you could but for what cost...
> They mostly recover PMs in copper cells. AR is used for refining.


at what cost?
this is an electrolytic cell that I can make at home. not a rocket science, if you ask me:

https://www.youtube.com/watch?v=D9J4hcbX0R0

you don't even need electricity for the motor, just use a wind generator


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## g_axelsson (Mar 20, 2017)

Where to start...

Scale do affect recovery rate. There is always losses in every process, amount of gold held back in a filter for example is the same if you are filtering 0.1 or 10 liters. Improper incineration and then AR treatment locks up some gold in any carbon left. Gold locked inside components can be hard to get for a hobby refiner.

The big guys smelt the material and create copper bars, in the process most of the precious metals are collected and recovered in the copper electrolysis step. That way they can get a more complete recovery than someone working in the backyard.

Why not mixing materials... because it's impossible to get a complete separation of it afterwards. If the processing is the same after incineration then there is no problem with mixing it, but if there is different base metals or processing methods then mixing creates more job or even higher losses.

And that electrolysis cell... maybe not rocket science but they still managed to make a big mistake... any contamination that doesn't dissolve would form an anode sludge at the bottom or in an anode bag, putting a stirrer without bagging the anodes will have the contamination suspended in the solution and it can mechanically be included in the finished product, lowering the purity. Then measuring 99.99% purity with XRF... I don't trust it.

Göran


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## shmandi (Mar 20, 2017)

No, it is not a rocket science. But even rocket you can make at home.
If you do the process that industry does manually, you will get very old before you get any result. And your profit will be negative.
You need to separate metallic and non metalic parts. You need to separate ferrous and other metals. Then you can start recovery and refining is the last step. 
The way I read you, you would just toss everything in AR. Yes, hard way is also a way to learn...


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## patnor1011 (Mar 20, 2017)

In the video you got "inspiration" from they process inquarted gold not cell phones. Big difference. Aqua Regia is stuff to be used on purifying dirty gold powder, processing rest of inquarted karat gold after nitric digestion of silver, perhaps ceramic cpu and cpu pins but certainly not on anything you do have on your pictures.
Maybe your problem is language barrier? Where are you from? I think that there may be experienced members here from your country which may be able to guide you or explain basics to you.


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## anachronism (Mar 20, 2017)

Well Pat, whatever his inspiration, he clearly knows more than most of us.


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## kernels (Mar 20, 2017)

shmandi said:


> The way I read you, you would just toss everything in AR. Yes, hard way is also a way to learn...



Quote of the day :lol:


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## rickbb (Mar 20, 2017)

anachronism said:


> Well Pat, whatever his inspiration, he clearly knows more than most of us.



Makes one wonder why he's here asking questions at all.


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## Topher_osAUrus (Mar 20, 2017)

kernels said:


> shmandi said:
> 
> 
> > The way I read you, you would just toss everything in AR. Yes, hard way is also a way to learn...
> ...



:lol: 
Yes....yes it is. But, isn't it better to learn via reading about the processes, and seeing the issues that others have encountered by doing the same thing that you propose? It may take some time to go over and read everything here on the forum in regards to escrap in AR.. But, that time you will spend doing that is EXPONENTIALLY less than the time you will kill by just "dumping it all together and let 'her rip!" then trying to figure out "where's my gold?!?".

Nobody here is trying to be condescending, on the contrary, we are all trying to help you not do foolish things that we have all done!


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## Zolotov (Mar 20, 2017)

g_axelsson said:


> The big guys smelt the material and create copper bars, in the process most of the precious metals are collected and recovered in the copper electrolysis step.



Thanks!
By any chance, do you know the name of the process in the academic world? Because I was trying to google "copper electrolysis" and can't find anything except extracting or purifying copper. 
However I found this document:
http://www.ct.ufrgs.br/ntcm/graduacao/ENG06631/5-b_copper.pdf
"Ag, Au and Pt are more noble than copper and therefore will not dissolve
anodically. They will be found as metals in the anode slime;" 
I do not understand fully what does it talk about, but looks like the document is on subject.


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## g_axelsson (Mar 20, 2017)

That document is spot on, and should be enough for building a copper refining cell. If you don't understand it you are lacking basic knowledge and you need to study more. "Electrorefining of copper" is the right scientific and engineering term.

Producing high enough copper quality by smelting isn't easy, you need to remove iron, zinc and other contamination first before the copper is good enough to be run in a cell without fouling the electrolyte too fast. This is a process that works best at a larger scale. The copper refinery close to me is running the copper smelter with batch sizes of hundreds of tons per melt.
There are some members that is refining electronics by smelting and a number of threads is discussing that. Use the forum search and study a lot more.

It is also considered good tone here on the forum to at least tell us where in the world you are from. You can do it in the user control panel. Rules, regulations, chemical names and availability differs between different geographical regions.

Göran


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## Zolotov (Mar 20, 2017)

I separated the ashes in ferrous (right) and non-ferrous (left) with the magnet.



and I panned it, but didn't find any visible gold wires.



I wonder if it would be better to pass the ashes through HCl to remove the tin (and iron if some of it is still present) before trying AR ?


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## Platdigger (Mar 21, 2017)

Just remember to test your solutions. Some of your pd can go into hcl, and even some gold if there is enough oxygen or oxidizer present.


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## patnor1011 (Mar 21, 2017)

In order to recover bonding wires efficiently you need to incinerate and grind material to flour consistency. Your material is too coarse, wires are likely still trapped inside. 
You do it opposite way. You need to incinerate, grind and sieve material first. Then separate ferrous metal parts which should be just wires and pieces of metal shielding/heatspreaders and not whole pieces of not crushed IC.

Do yourself a favor, read through my thread, read it all, and only then try it. You will then see how it has to be done instead of shooting in the dark.


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## Seny2021 (Sep 19, 2022)

Zolotov said:


> Thanks for the input.
> 0.5 g of gold is very low, I am puzzled.
> Lets say I processed it and got the 0.5g but I still wouldn't understand where the gold leak is.
> This is my math:
> ...


As far as I know in 4kg of Pcb you can get around 7g or a litle more


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## Yggdrasil (Sep 19, 2022)

Seny2021 said:


> As far as I know in 4kg of Pcb you can get around 7g or a litle more


I think that is overly optimistic.
Some one with number might give you some heads up on this.
Most if not all, the values are inside the ICs and other components not the PCBs


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## Martijn (Sep 19, 2022)

Zolotov said:


> I just turned off the incineration process. I processed the chips together with the small items (resistors, capacitors and other tiny stuff) and I have some substance of yellow color at the top. Is this some dangerous compound? Or maybe it is sulfur? I didn't see this yellow stuff on youtube videos, probably I did something wrong. I had it for 1 hour burning, at the beginning there was some small smoke, but after about 40 minutes smoke totally disappeared. Probably I shouldn't mix the chips with the small items.
> Here is the pic:
> View attachment 35247


Before you incinerate you have to pyrolyze without oxygen, burn the released toxic gases completely and when everything is reduced to carbon, incinerate. 

The way you did it only takes gold up in smoke and shortens your lifespan if those gases are inhaled. 

Stop and study. There are no shortcuts here.
Suggest your idea before you try it. 

As said, treat different components separately to recover the5 precious metals. Then refine to separate the values.
Edited: I just realized i replied to a five year old post... 
Senn, you sure do get things confused.


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## Seny2021 (Sep 20, 2022)

Martijn said:


> Before you incinerate you have to pyrolyze without oxygen, burn the released toxic gases completely and when everything is reduced to carbon, incinerate.
> 
> The way you did it only takes gold up in smoke and shortens your lifespan if those gases are inhaled.
> 
> ...


100% coreect


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## Seny2021 (Sep 20, 2022)

Seny2021 said:


> 100% coreecti saw someone depopulating the boards and burning them all then burning all the small parts and processing both with aqua Regia then he used sulphuric acid for the ICs in stainless steel 304 grade pot and what came out of there was 7g of gold total he maybe did it wrong or right but that's what I saw I will send the link to his page




These items we shall need for gold recovery from gold fingers.


*Nitric Acid (HNO3)*
*Hydrochloric Acid (HCl)*
*Sodium Metabisulfite (SMB)*
*Urea*
*Filter Paper*


Dissolving:​Take gold fingers in bucket or beaker. Add HCl until gold fingers dip. If 1 liter HCl use then adds 250 ml water. Now add some nitric acid. Don’t add a large quantity of nitric acid. Only 50 to 100 ml nitric acid use every time. Add nitric acid until all metals of gold fingers dissolve. Leave the solution for four hours and give some shake after every hour.

Precipitation:​After four hours filter the solution with filter paper or fabric.

Wash well. After washing, add urea to neutralize nitric acid in our gold solution. If you don’t use. You will face trouble for precipitation of gold. Add urea until reaction and then give a twist to the solution. Take about 20-gram SMB for 1 kg gold fingers. Dissolve SMB(sodium metabisulfite) in 1-liter water. Then add SMB solution to the gold (royal water)solution. Leave it overnight


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## Seny2021 (Sep 20, 2022)

Seny2021 said:


> These items we shall need for gold recovery from gold fingers.
> 
> 
> *Nitric Acid (HNO3)*
> ...


This is what I saw him doing for depopulated celphone board and other parts after burning them all without the ICs they were done separately


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## Yggdrasil (Sep 20, 2022)

Seny2021 said:


> These items we shall need for gold recovery from gold fingers.
> 
> 
> *Nitric Acid (HNO3)*
> ...


You have studied too much videos and not enough C.M. Hoke

This method is wasteful and has a risk of producing explosive compounds and loss of Gold.
Dissolving the fingers should be done with either AP or Nitric alone until the foils are released from the fingers.
If one use AR one has to make absolutely sure ALL the base metals are dissolved.
This usually end up with using too much Nitric, and the surplus has to be destroyed (not neutralized) by Sulfamic.
When the solution is free of Nitric and still acidic pH 1-2 range, add SMB in your own way, dissolved or powder don't make much difference.
Add 1:1 according to expected Gold yield.
If very dilute or high in base metals one will have a very fine precipitate which will take time to settle. 
If its fairly concentrated and clean it will drop more or less instantly.


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## Yggdrasil (Sep 20, 2022)

Seny2021 said:


> This is what I saw him doing for depopulated celphone board and other parts after burning them all without the ICs they were done separately


What do you mean with Burning here?


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## Ultrax (Sep 20, 2022)

Zolotov said:


> I just turned off the incineration process. I processed the chips together with the small items (resistors, capacitors and other tiny stuff) and I have some substance of yellow color at the top. Is this some dangerous compound? Or maybe it is sulfur? I didn't see this yellow stuff on youtube videos, probably I did something wrong. I had it for 1 hour burning, at the beginning there was some small smoke, but after about 40 minutes smoke totally disappeared. Probably I shouldn't mix the chips with the small items.
> Here is the pic:
> View attachment 35247


Yes, it is dangerous and toxic. It is litharge (PbO). Don't breathe with it.


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## Seny2021 (Sep 20, 2022)

Yggdrasil said:


> What do you mean with Burning here?


Burning meant=Incinerate


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## Seny2021 (Sep 20, 2022)

Yggdrasil said:


> I think that is overly optimistic.
> Some one with number might give you some heads up on this.
> Most if not all, the values are inside the ICs and other components not the PCBs


I'm still studying I have messed up a lot following this videos so far I have only been experimenting 
Still got I've 1000cellphon PCBs waiting 
And maybe 200 desktop PCBs 

I'm doing research so I don't waste so every kind of criticism is welcome please correct me by the way I donated I think 2 days ago
I'm living this forum


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## Seny2021 (Sep 20, 2022)

Seny2021 said:


> Ordered my air pump crucible filters smb etc


Someone one said to me if you wanna do recycling start with a big amount because you might not be able to recover you cost and I believe him from what I have see during this 1 year, recycling is not so easy as they show in videos


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## Yggdrasil (Sep 20, 2022)

Seny2021 said:


> Burning meant=Incinerate


You should really pyrolize first, with reburn if the fumes.


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## Yggdrasil (Sep 20, 2022)

Seny2021 said:


> I'm still studying I have messed up a lot following this videos so far I have only been experimenting
> Still got I've 1000cellphon PCBs waiting
> And maybe 200 desktop PCBs
> 
> ...


Are all these PCBs depopulated?


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## Yggdrasil (Sep 20, 2022)

Seny2021 said:


> Someone one said to me if you wanna do recycling start with a big amount because you might not be able to recover you cost and I believe him from what I have see during this 1 year, recycling is not so easy as they show in videos


Videos almost always lies.
They are not made for education, but for clicks and views to generate money for the maker. Shortcuts everywhere, all mistakes are removed and they get these massive yields from things containing next to no Gold.


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## Seny2021 (Sep 21, 2022)

Yggdrasil said:


> Are all these PCBs depopulated?


Yes


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## Yggdrasil (Sep 21, 2022)

Well then all the gold you have is what you see on the board.
So if each board is well, estimated to 6 by 12 cm and 100% plated at the thickest ENIG, about 0.2 micrometers.
100 boards will give around 25-28 ish grams of Gold.
But since the plating area usually are less then 5-10% of the area, we are down to best scenario 2.5-2.8 grams.
And then the ENIG is usually in the lower end so we end up with around half of that again.
So somewhere between1 and 1.5 grams at best per 100 boards.


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## Seny2021 (Sep 21, 2022)

Yggdrasil said:


> Well then all the gold you have is what you see on the board.
> So if each board is well, estimated to 6 by 12 cm and 100% plated at the thickest ENIG, about 0.2 micrometers.
> 100 boards will give around 25-28 ish grams of Gold.
> But since the plating area usually are less then 5-10% of the area, we are down to best scenario 2.5-2.8 grams.
> ...


A lot of those heave black berry boards I should count how many I have


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## Seny2021 (Sep 21, 2022)

Yggdrasil said:


> Well then all the gold you have is what you see on the board.
> So if each board is well, estimated to 6 by 12 cm and 100% plated at the thickest ENIG, about 0.2 micrometers.
> 100 boards will give around 25-28 ish grams of Gold.
> But since the plating area usually are less then 5-10% of the area, we are down to best scenario 2.5-2.8 grams.
> ...


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## Seny2021 (Sep 21, 2022)

Thank you for this I really appreciate it its helping get somewhere


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## orvi (Sep 21, 2022)

Yggdrasil said:


> Well then all the gold you have is what you see on the board.
> So if each board is well, estimated to 6 by 12 cm and 100% plated at the thickest ENIG, about 0.2 micrometers.
> 100 boards will give around 25-28 ish grams of Gold.
> But since the plating area usually are less then 5-10% of the area, we are down to best scenario 2.5-2.8 grams.
> ...


According to my crappy maths, 6 x 12 x 0,00002 cm = 0,00144 cm3 of gold. x 100 boards will get 0,144cm3 of gold, which is 2,77g of gold. 
If we assume 10% coverage by gold plating, that yields 0,277g of gold.

ENIG is usually 0,05-0,23 um thick, so we are at the top side of the spectrum of thickness. There is high probability that actual yield would be a fraction of the above number.


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## Yggdrasil (Sep 21, 2022)

orvi said:


> According to my crappy maths, 6 x 12 x 0,00002 cm = 0,00144 cm3 of gold. x 100 boards will get 0,144cm3 of gold, which is 2,77g of gold.
> If we assume 10% coverage by gold plating, that yields 0,277g of gold.
> 
> ENIG is usually 0,05-0,23 um thick, so we are at the top side of the spectrum of thickness. There is high probability that actual yield would be a fraction of the above number.


Well I might have missed a decimal or two, since I used the phone calculator.
I thought it looked a bit high.


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## Sancho_n_Pedro (Oct 29, 2022)

Quite an interesting approach, but I was thinking of doing the following:

1. After tearing down all phones remove anything with metal pins for processing later
2. Remove all Aluminum/steel covers and place in appropriate pot (Alu for casting use, iron is scrap)
3. Remove pin chips for later, along with any visible MLCC 
4. All boards (populated) are broken down through an old cast iron sausage mince machine, then run through a blender to make everything dust

Unsure on the next steps as I have no acid available and am still reading Hoke's guide. I have the thought that I could use AP to remove all tin (solder) etc first, but am open to suggestions.

Doing this is more of a therapeutic exercise for me, as I know it will cost more on low quantities of materials, and had planned to follow the guide of Hoke with the suitable materials I have to hand, but I feel one read of her book is not enough, so more study is done before I delve into using any acids.

If anyone has thoughts on what I am intending to do, I'd appreciate the advice. I don't care for the money right now, as its a learning exercise and once I understand things more I will probably look to get items of better quality (and less tedious).

Thanks


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## dannlee (Oct 29, 2022)

Didn’t see it mentioned - Beryllium alloys used since they make light & strong whatzits to keep weight & size down.. . Berylliosis.

Zero dust from, burning of or muddling in ashes that might* have berylilum traces in them.


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