# Question about cellphone board and there ics



## imran zafar (Dec 22, 2013)

hello
i am a new member of this great forum 
most respected members i have some questions about 
my 1st experiment , for gold recovery from cellphone ICs

i buy 1lb mixed cellphone boards remove all ics from there
witch ware just 30 grams.

then i only select ICs (30gm) for my 1st experiment ,i burnt them 
filter ash by plane water and dip them in to very little amount of 
AP after dissolving of base metals i filter the solution and dip the
remaining material into AR, filter again neutralize with UREA
drop gold by pmb(potassium metabisulphite ) smb was not available 
finely i recover 160mg gold from those ICs. 
now my 1st question about my final procedure when i mix 
potassium metabisulphite (half ts) in solution then(after an hour) i saw a strange 
thing,,,,a unexpected item like very small pieces of paper was producing from 
solution well i decide to left the solution over the night to settle gold powder in bottom 
at morning i see a very tin layer of gold dust witch was settled in bottom and the top of my 
jar was full of strange crystal foam ,,,when i stair the solution both item gold and crystals of foam
mixed again into solution and disappear i wait 15min but no thing happen again 
then i put some urea give a little heat to solution and add potassium metabisulphite again
this time my solution color was dark brown and when i stair sudden what i see there is alot of 
black balls (very small size) are producing and settling down a stair again for 2 minute and all the balls 
convert in dark brown powder i filter 3 time that powder by water 1 time by HCL 2 time again by water
dry it melt my 24k gold,,,the yield value of gold from 30 gram ics is normal or i can expect more :mrgreen: ??
my 2nd question 
how much gold can i expect from my 1lb board(ICs less)?

sorry about my English


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## butcher (Dec 22, 2013)

I cannot comment on how much gold to expect from the Integrated circuits on the cell phone boards, my guess it would depend on many factors, like which IC's,which cell phone's, and how much gold the manufactures used in those IC's used to make the circuit, and how well you are able to recover it.

I do see where you may improve your processes in recovery of that gold, for one in how you are treating the material, and using your chemicals. You may find you can get more gold by processing the material differently.


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## Pantherlikher (Dec 22, 2013)

How about doing Alot more reading up on how to properly process said material.
For 1 thing, Urea will NOT neutrilize Nitric acid in AR. Learn how to do it the right way will help. 
Also learn what will precipatate Gold and what will not. What will substituting other things do?. 

"i burnt them 
filter ash by plane water and dip them in to very little amount of 
AP after dissolving of base metals i filter the solution and dip the
remaining material into AR, filter again neutralize with UREA
drop gold by pmb(potassium metabisulphite ) smb was not available 
finely i recover 160mg gold from those ICs."

You said you dip them? English is tough yes, Dip means to put in and pull out quickly. Soak might be better or put in. How long in AP? And how much is very little? It takes a long time and alot of AP to work on removing all base metals.

"pmb(potassium metabisulphite )" What will this do to metals dissolved in AR?
Please describe.

Just trying to help be clear in learning.

B.S.


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## solar_plasma (Dec 23, 2013)

> drop gold by pmb(potassium metabisulphite ) smb was not available



I use it too in gold solutions, but you have to be aware of, that potassium solutions may form barely soluble complexes with PGM's, as far as I understand and remember.

I don't know if this can have anything to do with your strange observations.


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## imran zafar (Dec 23, 2013)

thanks all of you for your quick reply,
basically i am a cellphone technician and never work with 
chemicals and acids but as i read fume from these acid
are very toxic and extremely dangerous for our body so 
i decide to stop my work and i should learn about safety 
so i am planing to build a safe fume hood 1st .

but i have a still question on my mind and not able to find answer 
(i use search option lot of time but no success) 
as i read in forum http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=60&t=15984&start=60

so if a single cellphone board yield 0.0165g gold then witch part have
excessive gold in it ICs/PCB/CONNECTORS/ ?

gold from pcb %
gold from ICs %

or gold from other parts %


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## solar_plasma (Dec 23, 2013)

Mainly in the IC's (also the CCD), commonly it variies between 0,1 and 6g/kg - in order to be safe I would guess somewhere in the lower middle (1-2g, might be much more) in this case and in gold plated areas (board, connectors) and items (fx microphones, pins), here the yield depends on plated surface areal and thickness of plating.

To make an unprecise guess, I would compare this material with RAM's, which often have 50% of the gold in the plating and 50% in the IC's.

As I said, this is a very unprecise guess and can't be used for any pricing, only to have a diffuse feeling, what MAY be to expect.

I'd like to add, that in my opinion cell phones may be one of the most difficult materials to start with. I get my 0,12g from a pentium 1 with ease or my 1g/ 120 RAMs, but I guess I wouldn't get half of the PM's out of a cell phone with the same effort. That is because here you have to be skilled in ALL kind of processes and need a large lot of boards to have enough of every kind to start a process economically.

This should not be a reason for you to start with other material, it is only necessary to read more than for some other more easy stuff and to take the time and practical exercises it will need to feel safe with all implied processes


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## chlaurite (Dec 23, 2013)

imran zafar said:


> finely i recover 160mg gold from those ICs.


That sounds more or less correct for 30g of chips. North bridge flatpacks yield around 2.5g/lb. For similar quality chips (and with bonding wires, "quality" basically means pin density), I would expected you to get 120 to 150mg. The slightly higher yield may reflect a higher pin density in the as-small-as-possible parts used on cell phone boards.


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