Processing mobile phone parts

[Seny2021]

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

1. Nitric Acid (HNO3)
2. Hydrochloric Acid (HCl)
3. Sodium Metabisulfite (SMB)
4. Urea
5. 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

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

 

[Yggdrasil]

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

1. Nitric Acid (HNO3)
2. Hydrochloric Acid (HCl)
3. Sodium Metabisulfite (SMB)
4. Urea We do not use Urea, Use Sulfamic acid
5. 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

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.

 

[Yggdrasil]

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?

 

[Ultrax]

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.

 

[Seny2021]

What do you mean with Burning here?

Burning meant=Incinerate

 

[Seny2021]

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

 

[Seny2021]

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

 

[Yggdrasil]

Burning meant=Incinerate

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

 

[Yggdrasil]

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

Are all these PCBs depopulated?

 

[Yggdrasil]

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.

 

[Seny2021]

Are all these PCBs depopulated?

Yes

 

[Yggdrasil]

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.

 

[Seny2021]

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.

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

 

[Seny2021]

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.

 

[Seny2021]

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

 

[orvi]

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.

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.

 

[Yggdrasil]

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.

 

[Sancho_n_Pedro]

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

 

[dannlee]

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.