AR process: SMB works but doesn't drop

[Marcel]

[*]I processed 20 goldplated CD-Rs in poor man´s AR ( HCl + Clorex/Chlorox). I the thin foils removed from the disc prior to processing.
[*]All the gold was dissolved fast.
[*]Received a greenish solution,
[*]Let it stand overnight.
[*]Heated it to 55° for about 30 minutes
[*]Filtered the solution, washed the remains in the filter (mostly paper and stickers)
[*]Received the yellow solution. Looked perfect.
[*]Added 10g of SMB.(dissolved in 100 ml water)
[*]Solution turned dark-purple/brown but no sediment.
[*]Added another 5g SMB.
[*]A bit of chlor evapourated, solution unchanged.
[*]Tested it with Stannous chloride= receive a pale brown color.

Problem:
Now what I have here is a dark solution that looks as if everything was fine, but there is no "drop". I dont want to add endless amounts of SMB until it is clear what went wrong.
And Stannous only gives me a light brown color no dark purple as there should be.

Any suggestion onw hat went wrong or how to fix it?
I did a similiar batch yesterday, but had additional foils from PCI cards in it.
It worked but there may be silver involved, because the button shows some silver(?) in it, which can not come from the foils.

 

[nickvc]

Two things come to mind, one that the chlorine hasn't been removed, try heating your solution and see if that helps. The other is that perhaps the gold content is so low that all you have is a colloidal solution now. Have you tested the solution with stannous to see if you have any gold left in solution.

 

[Marcel]

Chlorine - I heated the yellow solution to 55° , forgot that step in my list. Heating now may help, too?
Low gold content - that may be the case :-(
Stannous chloride is light brown. Unfortunatly I did not test the yellow solution .

 

[etack]

Pale brown after SMB means you added to much SMB.


Also poormans AR refers to a K or Na nitrate and HCl. HCl and bleach is acid/Clorox

The forum has discussed gold plated CDs before and some say there is gold; most say not a lot.

Eric



spelling

 

[Marcel]

Thank you Eric for putting this right.
Of course it´s HCl bleach!
I have read that CD-Rs contain 20mg to 40mg (milligramm) per disk. So about 30 of them could contain 1 g gold at best. (I never tried them before) http://www.obviously.com/recycle/guides/hard.html
I took 20 and added 15g SMB, so that was quite too much if related 1:1.
Is there anything I can do with my process now?

 

[maynman1751]

Just warm it for a while to help drive off the Cl and SO gases. Then see if there is any powders. It may take a while...that's a lot of SMB!!!!

 

[Marcel]

Will warm it for some time and see what happens. How will I know it´s done? will the solution clear up ?
Just to explain: I prepared 10g SMB in water but did not expect to need so much. So I added and stirred, the solution color changed but no drop. So I added more. I did not really know how much blackpowder to expect, so I though there was more in there and I kept on adding.. :-(

Update:

After warming the solution for 30 min. now it looks much better. It is clearing up and I can see the brown powder that is beeing dropped on the bottom.
Looks like less than 0.5g at the moment to me.

 

[Geo]

it could be quite a bit. after warming to a good steam, let it stay at that temp for 15-30 minutes until you DONT smell sulfurous smell from the solution and then allow to cool.when cool any gold that was trapped by the SO2 bubbles will be settled and the solution should be as clear as water(even if colored). this only happens if the solution is murky or clouded to begin with (holding it up to the light and its not clear like water).SMB evolves SO2 bubble in open solution, and will continue until the reaction with water stops.as the gold atoms coalesce into large enough particles, SO2 gas bubbles will adhere to them.this happens at or near the end of the process when the particles do not have enough weight to overcome the buoyancy effects of these tiny microscopic bubbles.warming the solution breaks the bond between the gold and the SO2 bubbles letting the bubbles rise to the surface and the particles settle to the bottom.

hope this helps.

 

[etack]

I have read that CD-Rs contain 20mg to 40mg (milligramm) per disk. So about 30 of them could contain 1 g gold at best. (I never tried them before) http://www.obviously.com/recycle/guides/hard.html

I looked at the site and its interesting. the problem I see with the 20-40mg of gold for each CD-R is that I can buy 100 for 14.99US with free shipping. the math seems off.

At 20mg per 1 I would be buying 2g of gold for 14.99US which I would if I could.

some of the archiving cd-r have a gold layer but in the pennies pr disk. $0.80 per disk at today's gold price 1659
http://reviews.cnet.com/blank-cd-media/delkin-efilm-archival-gold/1707-3221_7-31202150.html
The article was written in 2004 gold price average was 409.35
If you found these cheep and in quantities this might be a source for gold.

Eric

 

[Marcel]

I did buy 1 ton of CDs/DVDs(approx. 100.000 pcs) a few years ago and I handselected 400 golden with thick gold layer (They are so thick plated, you can just peel them off).
They are from the 80s/90s. Later, CD-Rs where made using silver and , i think even aluminium. Today´s CD-Rs dont have much gold in them if any.
Just a try, I will report the yield, if there is anything to be reported )

 

[Marcel]

I did buy 1 ton of CDs/DVDs(approx. 100.000 pcs) a few years ago, they were all mixed types and I handselected 400 golden with thick gold layer (They are so thick plated, you can just peel them off).
They are from the 80s/90s. Later, CD-Rs where made using silver and , i think even aluminium. Today´s CD-Rs dont have much gold in them if any.
Just a try, I will report the yield, if there is anything to be reported )

Btw: Here is a german report on deplating CD-Rs with a electrolytic process
They yielded 8,9 mg per Golddisk and 10,2 mg - 18 mg for silver.
They also calculated that the layer is 170 goldatoms thick
from Rhur university, chemistry facility:
http://www.ruhr-uni-bochum.de/rubin/rbin2_01/studieren/index.html

 

[etack]

That sounds cool I have never seen any like that. 8) I also don't think I have seen a CD from the 80's in real life. I know they were made. Do you think that there could be gold on laser discs as well. some of those can be cheap.

Eric

 

[maynman1751]

it could be quite a bit. after warming to a good steam, let it stay at that temp for 15-30 minutes until you DONT smell sulfurous smell from the solution and then allow to cool.when cool any gold that was trapped by the SO2 bubbles will be settled and the solution should be as clear as water(even if colored). this only happens if the solution is murky or clouded to begin with (holding it up to the light and its not clear like water).SMB evolves SO2 bubble in open solution, and will continue until the reaction with water stops.as the gold atoms coalesce into large enough particles, SO2 gas bubbles will adhere to them.this happens at or near the end of the process when the particles do not have enough weight to overcome the buoyancy effects of these tiny microscopic bubbles.warming the solution breaks the bond between the gold and the SO2 bubbles letting the bubbles rise to the surface and the particles settle to the bottom.

hope this helps.

Thanks Geo for the more detailed description of what I said. It helps members with better understanding of what's actually taking place. I'm still too green to do the detail thing! :mrgreen:

 

[Marcel]

That sounds cool I have never seen any like that. 8) I also don't think I have seen a CD from the 80's in real life. I know they were made. Do you think that there could be gold on laser discs as well. some of those can be cheap.

Eric

You cannot use normal CDs, you need rewriteable like CD-R´s.
Here are the results:

Yield is low: Less than 0,15g
19 discs were proceeded
so less than 0,01g /disc ....