# No Gold Recoved After Melting The Gold Dust.



## Vidya (Feb 10, 2022)

I have tried to recover gold from 18 cell phones and It seems everything right before I melted the gold dust. This is second time, I melted the gold and I haven't received any gold from it. I am so Frusted, can anyone guide me what I was doing wrong.


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## FrugalRefiner (Feb 10, 2022)

While I have never processed cell phone boards, I wouldn't expect much gold from 18 phones. 

Did you remove all the components from the boards first, and just process the boards? Or did you put the boards in with all the components still on them?

Did you test your solution with stannous chloride before you tried to drop the gold? What was the result?

How did you drop the "gold dust"?

What did the "gold dust" look like before you tried to melt it? How much was there?

Maybe others can give some kind of idea on what to expect.

Dave


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## Vidya (Feb 10, 2022)

I removed all the components before processing the boards. I tested with stannous chloride and the test was positive. The dust was looking light black and I used smb for precipitation.


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## Vidya (Feb 10, 2022)

The dust was around a 0.8 to 1 gram


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## cejohnsonsr1 (Feb 11, 2022)

Vidya said:


> The dust was around a 0.8 to 1 gram


No way you get 0.8 gr from 18 cell phone boards.


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## Vidya (Feb 11, 2022)

How much dust I can get from 18 cell phones


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## Vidya (Feb 11, 2022)

And how much gold can be recovered?


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## nickvc (Feb 11, 2022)

In answer to your question we have an old saying “ how longs a piece of strung “ this basically means there is no correct reply to your question as it depends on the types of phones their age and your skill at recovery and refining.


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## orvi (Feb 11, 2022)

Vidya said:


> I removed all the components before processing the boards. I tested with stannous chloride and the test was positive. The dust was looking light black and I used smb for precipitation.


Positive stannous is one thing, recovery of the gold is the other.
Stannous is very sensitive test. Even a very small ammount of gold is detected. And small ammounts of gold, meaning less than 0,1 grams, are very difficult to collect without significant losses.

Gold cannot escape from the melting dish. If you had 1 gram of something mixed with small amount of gold, gold could be still there, but never clumped together forming beads. What was left after that melt ? Some slag formed ? Does it smoked when you were melting it ?


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## Vidya (Feb 11, 2022)

No there was no smoke.


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## Vidya (Feb 11, 2022)

Should I have to try to recover in a large quality or I have done any mistake.


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## Yggdrasil (Feb 11, 2022)

Since "modern" cellphones has little gold in them, if you want more gold you need larger volume.
But on the other hand, the risk of loss to process errors also rise.
So until you find a way to process them successfully in small scale there is no sense in scaling up.


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## Vidya (Feb 12, 2022)

Yes, you are right.


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## Vidya (Feb 12, 2022)

May I know how much gold can be recovered from 100 cell phones and at what price I should buy.


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## Yggdrasil (Feb 12, 2022)

I have no Idea regarding price. Personally I take them if I get them for free.
Never bought one.


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## nickvc (Feb 12, 2022)

In honesty I would suggest finding better material for working with , according to Umicore there’s 300 grams of gold in a ton of mobile phones without the batteries and that may well include the oldest phones produced which would really be much higher in gold content.


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## Vidya (Feb 13, 2022)

Thanks guys, you help me a lot.


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## MicheleM (Feb 13, 2022)

Vidya said:


> Should I have to try to recover in a large quality or I have done any mistake.


Maybe a detailed list of the steps you did would help to find possible mistakes if any. 0.8 g from 18 ordinary Nokia cell phone looks too strange


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## Vidya (Feb 14, 2022)

First I removed all the components from the board and remove the gold plating using nitric acid. After the 1st step there was a little bit of tin so I washed the solution on hcl to remove the tin. After the wash tin has been remove and only gold left. Then I made 40 ml aqua regia and devolved the gold into it. After the gold devolved I filtered the solution and done smb for gold precipitation. The dust has been settled, but When the melted the dust. There was no gold.


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## MicheleM (Feb 14, 2022)

" remove the gold plating using nitric acid. After the 1st step there was a little bit of tin so I washed the solution on hcl to remove the tin" 

Do you mean that on your PCBs were still gold plated areas and tin after the nitric acid bath or that the gold foils was floating in a nitric solution alongside with some tiny lump of tin? (Anyway Nitric bath followed by HCl can result in some dissolved gold, next time try HCl first to get rid of tin and then CuCl2 method )

"Then I made 40 ml aqua regia and devolved the gold into it. After the gold devolved I filtered the solution and done smb for gold precipitation. The dust has been settled,"

How much HNO3? Did you de-nox the solution? How much SMB?


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## GoIdman (Feb 15, 2022)

Cell phones are the worst things I have ever worked with. I hate that stuff...is very labour intensive stuff (separation of batteries, disassembly, separation of plastics-rubber-glass, separation of gold plated parts magnetic/nonmagnetic, separation of board and components, treating the board to remove solder or trimming the edges to remove gold bearing pcb parts... no thank you). After processing all the gold bearing stuff i have come out losing money on it (i have to note that i was aware that i will lose money on it but accounted for learning money...the loss was not astronomical).
The problem i have found is the labour cost in hours, if you do not mechanize everything (shredder, grinder, separation before treatment, acids, refining, melting).
If you have an unlimited supply of mobile phones you may get in the business to refine gold from boards, but my advise is to find and mechanise all separation processes for you to turn on profit, or just disassembly the things and resell the disassembled the separated and sorted parts, you may end up making more money then refining.
By the way, i have processed mixed batch phones (from old nokia and siemens to more modern smartphones) I still hate that stuff )

Be safe

Pete


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