PM from CD or CD-R?

[joem]

I was talking about CD discs not the drives

 

[GotTheBug]

I actually just played with this recently. Had a few of the premium discs with a bit of gold and over 100 "regular" cd's, cd-r, some installation, etc.

The gold was, indeed, gold, though not much.
The regular cd's, and this was funny, were obviously aluminum.

I used a razor blade to just lightly score the coating approximately every 3/4 inch around the disc, then dropped them into some HCl, which made short work of separation.

The gold ones separated nicely and left a bit of gold "dust" in the bottom of a mess of "coating flakes". Again, not much, but it's there.

The aluminum obviously completely disintegrated, leaving the same "coating flakes", the polycarbonate discs themselves, and a light brownish colored HCl. Again, not worth the effort, but it was a learning experience.

Hope this helps.

 

[rickbb]

I used to work in a manufacturing plant that made CD's, (not CDR's). The metal coating is Al and is appx 50 microns thick. Its vapor deposited in a high vacuum chamber, then coated in lacquer. We did do some gold CD's, not many, and it was 24ct but still only 50 microns thick.

DVD's usually are coated in silicon as the reflective coating as that will reflect the blue/uv laser in the player better.

But again the reflective coatings are vapor deposited in microscopically small amounts. There only needs to be 70% reflectivity for the disc to play correctly.

I would think getting all the lacquer and polycarbonate separated would be really hard, and then you have plastic waste to get rid of.

 

[FrugalRefiner]

I used to work in a manufacturing plant that made CD's, (not CDR's). The metal coating is Al and is appx 50 microns thick. Its vapor deposited in a high vacuum chamber, then coated in lacquer. We did do some gold CD's, not many, and it was 24ct but still only 50 microns thick.

That sounds awfully thick! Might it have been 50 microinches instead of 50 microns? Fingers, pins, and other contact surfaces are often estimated at 30 microinches thick. 1 micron equals 39.37 microinches. You're saying the coating on a CD is 65 times thicker than that on fingers.

Dave

 

[Claudie]

The 39th item down the list on this site:

http://www.computerplatinen.de/elektronik-recycling-preise/schrott-computer-platinen.php

That sounds like a pretty good buy price so they must be worth something.

 

[rickbb]

I used to work in a manufacturing plant that made CD's, (not CDR's). The metal coating is Al and is appx 50 microns thick. Its vapor deposited in a high vacuum chamber, then coated in lacquer. We did do some gold CD's, not many, and it was 24ct but still only 50 microns thick.

That sounds awfully thick! Might it have been 50 microinches instead of 50 microns? Fingers, pins, and other contact surfaces are often estimated at 30 microinches thick. 1 micron equals 39.37 microinches. You're saying the coating on a CD is 65 times thicker than that on fingers.

Dave

You are correct, I'm getting my micros, angstroms and nanos mixed up, and we actually measured it in its reflective value not an actual thickness. Above 70% pass, below it was scrap.

It's thin enough to see through when you hold it up to light in front of your eye. The deposit stage only takes 0.2 seconds on the production line so it's not much there even if it were gold. We made a complete CD ready for silk screen printing in 2.6 seconds total.

 

[rickbb]

The 39th item down the list on this site:

http://www.computerplatinen.de/elektronik-recycling-preise/schrott-computer-platinen.php

That sounds like a pretty good buy price so they must be worth something.

They could be buying them for the optical grade polycarbonate plastic and not the metals, that’s what we sold our scrap for back in the day. I don't think the price of scrap aluminum is that high to try and get it off a CD. But who knows stranger things have happened.

 

[solar_plasma]

At 100nm thickness it would take only 100 dvd-r with gold layer to yield about 2g gold, if my math is corect. Has anybody found out, if all gold coloured dvd-r's actually contain gold?

 

[necromancer]

At 100nm thickness it would take only 100 dvd-r with gold layer to yield about 2g gold, if my math is correct. Has anybody found out, if all gold coloured dvd-r's actually contain gold?

current price i am getting now is $0.16 per pound, i think that is better & faster + less waste.

what are most people doing with there left over parts ?

 

[Sharding757]

Found this on metal mine media while searching on the validity of it all: I don't know if what is claimed here to be true, but figured I'd offer it up for others to see.

http://www.metalminemedia.com/2013/03/presence-of-gold-in-cds-dvds.html

//I copied and pasted the content to avoid having to go to the site to read and possible spam//

Presence of Gold in CD’s & DVD’s
Thursday, January 31, 2013 2 comments

With a CD having a diameter of 12 cm, and the inner non-writable part having a diameter of 4 cm, we get a total writable area of around 100 cm². I read somewhere that the different densities of the “gold, silver, aluminum” layer are between 20 to 100 nanometers (billionths of a meter). Assuming the worst case scenario, 100 nanos, we get a total gold volume of 0.00001 cm³. At a gold density of about 19.5 g/cm³ this volume equals 0.000195 g. With one troy ounce equal to 31.1 g., this weight of gold equals 0.00000627 troy oz., or rather, one troy ounce of gold is good for 160,000 CD-Rs. At a gold price of U$S 450 per troy ounce, there is U$S 0.0028 gold per CD-R, or 0.28 cents worth of gold. Of course, the density of the gold layer could be as low as 20 nanometers. In that case, the gold content in the CD would be worth 0.06 cents, and one ounce of gold would be good for 800,000 CD-Rs. So there you have it.

One final step. 10 billion writable CDs are sold every year (versus 20 billion audio CDs). The gold/silver CDs are phthalocyanine, and I read this type of CD is second in market share. So let's give the gold/silver CDs a 25% market share. Now let's assume the gold variety is about half of that, so the total gold CD market share is about 12%, or 1.2 billion CDs annually. With one ounce of gold good for 160,000-800,000 CDs, we need a block of gold every year that is from 2,400 to 12,000 cm³ or a cube with each side being 13 to 23 cm long (5 to 9 inches). This block would weigh 100 to 500 pounds and be worth 700,000 to 3,400,000 dollars. So there you have it.

 

[johnny309]

In CD or DVD that are recordable(you can write them in your own computer)....they contain Ag.....12mg/piece to be precise.
So,in another words you will need 1000 pieces for 12 grams of silver. One disc weight 16 grams.
The commercial type (prerecorded) and the rewritable disc contain Al.

 

[rickbb]

This site has one of the best descriptions of what type of disc "may" contain silver or gold.

http://www.clir.org/pubs/reports/pub121/sec3.html

 

[solar_plasma]

Thank you, rickbb! If this info is complete, then all golden and green coloured (non-RW) types should contain some gold.

 

[rickbb]

Thank you, rickbb! If this info is complete, then all golden and green coloured (non-RW) types should contain some gold.

I would urge caution, as they "may" contain some PM's. When I was in the business we were just starting up a CD-R manufacturing line and we used AL, not silver. We ran the costing process on starting up a DVD-R line and the equipment we looked at used silicon on them, not gold.

Each supplier of the equipment had their own proprietary process for manufacture so there is a lot of variation in what is being produced.

We only sputtered gold on discs by special request and a serious up charge. A solid pure gold sputtering target was $20k in the mid 1990's. And boy was it sight to look at. It always gathered a crowd when the techs had to hang one in the line. Big gold doughnut!

 

[meatheadmerlin]

I stumbled onto a way to get at the layer of metal between the 2 layers of plastic in a DVD+R.

I had some difficulty writing one and took it into the back hall to snap it in half (in anger), like I sometimes do to CD-Rs that are problematic.

Well, it didn't snap. It bent in half instead, so I left it on the concrete floor there. The back hall is quite cold during winter, and when I returned there I tried to unbend it (for no good reason). It snapped in half then, and began peeling! The layers had separated where it was bent.

So, there may be hope to use mechanical stress then chilling to separate the layers. Perhaps bending the disc/disk into a curve, chilling, and then unbending would do the trick.

 

[nickton]

Huh? :shock:

 

[Tquilha]

I'm kinda raising this topic from the dead, but I just made my first experiments with e-waste, and it was just about this.
Getting the silver off old CDs and DVDs.
I can confirm that "pressed" CDs or DVDs have Al and no Ag. All advertising CDs and DVDs are the "pressed" type.
CD-R and DVD-R have Ag, but very little (very likely the 12 mg/piece mentioned here).
To process DVD-R all you need is a box cutter and some patience. Score along the rim of the DVD until the tip of the blade cuts into the disc. Then it's just a matter of slicing the two halves apart. Mind you fingers!
CD-Rs are different. They have a single layer of polycarbonate, then the silver layer and then a paper or plastic layer. All you have to do is score the paper layer with a cutter, so that the nitric acid can access the silver layer.
To dissolve the silver, all you need is to dunk the disc in dilute nitric acid. The reaction is quite fast.
Rinse the clear discs with distilled water into a separate bucket, and recycle the polycarbonate.
So far things look promising (for a 1st try) and I'll be cementing the silver with copper when I have enough solution.

 

[rickbb]

That metal layer is vacuum deposited and is appx 200 to 300 angstroms thick, which is 0.02 to 0.03 micrometers thick.

That's for CD and CD-R, DVD and DVD-R variants have even thinner coating due to them being multi layer construction, and the laser needing to focus through the various layers. DVD 5 and

Some math to calculate cubic area of the disk will tell you how many you will need to yield an ounce of metal.

 

[anachronism]

Waste of time unless you have tonnes and a process that's efficient.

 

[rickbb]

Waste of time unless you have tonnes and a process that's efficient.

AND assuming that the metal is actualy gold or silver, which most aren't.