# Hard drive PGM recovery/refining



## Anonymous (Mar 9, 2007)

I read that there is platinum in the disks in most hard drives. Supposed to be 10% to 35% with the amounts increasing the newer they are. 

I found a nice article with pictures here: http://www.bestgoldbuyers.com/platinum2.html

It also has pictures of a CPU in acid. with pins floating off of it.
Of note is a link to www.ActionMining.com with mention of - Platinum Group Metals Flux Cat#FLUXPGM1 

In addition, www.ActionMining.com has cuppels beaker, and a great many other selections of recovery/refining supplies.

Can someone more knowledgeable than me please advise if they know of a method to "de-plate" hard drive disks as in this picture?:
http://www.bestgoldbuyers.com/plat06smelt1.jpg

Or can you please offer an opinion as to the purity/value of this bead from a hard drive disk?:
http://www.bestgoldbuyers.com/plat06smelt11.jpg

Thanks, Ghengis


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## lazersteve (Mar 9, 2007)

Khan;

Thank you for the great link. 

The percentages are more than likely not relative to the entire platter weight, but rather relative to the coating layer weight alone.

Here's one that should help you out a little:

http://cgi.ebay.com/How-To-Refine-E...084980047QQcategoryZ47103QQrdZ1QQcmdZViewItem

If the BB in the photo is solid Pt (doubtful) it probably weighs around .1-.3 grams. It's purity is most likely within the percentage you already mentioned (10-35%) if your source is reliable. According to the ebay article (Thank you Ideasnow- Steve!) the coating is an alloy.

Steve


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## Anonymous (Mar 10, 2007)

Yes, sorry. I realize, but didn't verbalize. 10-35% of the very thin foil layers should have platinum, not the whole disk. 

Thank you for the ebay link. In short, a muriatic acid bath should do the trick, followed by smelting in a cuppel with PGM flux?? 

Now, if I understand, one should be able to place these beads in molten lead in a lead absorbing cuppel for about 40 minutes and the lead will draw off all non-PGM metals, then soak into the cuppel? Will this work/is it necessary?

I'm guessing they use an alloy of platinum,palladium, nickel?, etc? 
I would expect this to leave a bead of Platinum/Palladium maybe, but....
I don't know if this plan would work.
I don't know if some non-precious metal would still be in the beads.
I wouldn't know how to seperate the PGMs from each other. Or how to determine what ratio they are in within a sample. If I had several grams, of PGM beads, I would be curious of their ratios to know the true value. If I could know the ratio, then I wouldn't feel compelled to seperate the PGMs.

Steve, you mentioned that you imagine the bead is 10-35% Pt if my source is correct. I have multiple online sources that the Pt content is increasing with higher capacity drives. (again within foil layers, not the disk weight)
But my question here is if using the right cuppel, and PGM flux, will the bead really be PGMs, or is there risk of other (cheap) metals staying alloyed in there?


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## lazersteve (Mar 10, 2007)

Khan,

The best method would be to take the foil and dissolve it into AR before putting it in the cupel. From there you would precipitate with ammonia chloride, then the cupellation step.

Steve


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## NaNO3 (Mar 10, 2007)

> I'm guessing they use an alloy of platinum,palladium, nickel?, etc?


The magnetic coating most often used on hard disks has been a metal alloy of cobalt, chromium, and platinum.


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## shadybear (May 16, 2007)

> The magnetic coating most often used on hard disks has been a metal alloy of cobalt, chromium, and platinum.



Is the best way to remove the cobalt to use a cold AR rinse,
and what takes out the chromium?


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## lazersteve (May 16, 2007)

Hoke mentions Chronium in chapter 16 as follows:

-It does *not* disslove easily in nitric acid and is often mistaken for white gold or platinum for this reason.

-It dissloves readily in plain HCl or dilute H2SO4 (hydrochloric and sulfuric acids), if hot.

-If it should get into the AR it should cause no difficulty as it behaves like nickle in some respects and iron in other respects.

Here's some additional information on Cobalt:

-It is magnetic

-It forms CoCl2 when acted upon by Chlorine. 

-It is soluble in acids 

-It can form toxic salts

Based upon this information I've outlined this preliminary procedure. It's never been tested and will need to be verified experimentally. 






1) Dissolve the Aluminum platters usng HCl.
2) Pour off the liquid from the foils.
3) Rinse the foils throughly with water.
4) Add more HCl and heat to dissolve the Chronium.
5) Pour off the liquid from the foils.
6) Rinse the foils throughly with dilute HCl followed by several water rinses.
7) Allow the foils to dry and grind to a fine powder.
8) Run a magnet thru the very finely ground particles.
9) Platinum is not magnetic and should separate from the magnetic Cobalt if properly ground.
10) Process the Platinum using hot AR.
11) Drop the Platinum using Ammonium Chloride.





The separation of Platinum and Cobalt using a magnet may not be effective enough to completely divide the two. Boiling in Nitric acid may be the best method. Take precautions against forming ammonium nitrate if performing the separation using hot nitric acid. If you choose to go this route please do all your research first on the subject. You may want to start with this patent:

United States Patent 5039502.

I'll be experimenting in this area soon and will share my processes and results with the forum.

Steve


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## shadybear (May 16, 2007)

Seems simply except for that grind to powder, that may be a point that the how well ground could effect losses of platinum.

If the chromium causes no hassle in the AR why bother removing it?

Is there any other way to remove the cobalt? Other than
magnetic seperation?


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## lazersteve (May 16, 2007)

shadbear said:


> If the chromium causes no hassle in the AR why bother removing it?



Shady,

I try to remove as much 'trash' before I dissolve the precious metals to keep the 'drag down' contamination to a minimum. The fewer metals in the AR the cleaner it will separate when dropped.



shadbear said:


> Seems simply except for that grind to powder, that may be a point that the how well ground could effect losses of platinum.



I agree with your observations on using the magnet. I had the same feelings. 



shadbear said:


> Is there any other way to remove the cobalt? Other than magnetic seperation?



As I mentined in the post, Cobalt will dissolve in acids. This would include hot nitric as mentioned in the posted patent. 

I have *no* hands on experience with the suggested process so initailly experimentation on a small scale would be the ultimate test. I think when I perform my test I will try the HCl-Cl ('Clorox Method') to separate out the Cobalt after removing the Chronium. This method may gather some of the Pt into solution also, but it could be easily recovered using NH4Cl.

Steve


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## shadybear (May 16, 2007)

> Take precautions against forming ammonium nitrate if performing the separation using hot nitric acid



How do you take precautions to avoid this and why. IS this dangerous?


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## lazersteve (May 16, 2007)

shady,

I'm sure you are aware Ammonium Nitrate is an ingredient in some explosives. It can be explosive itself under some conditions. The US Patent that I quoted goes into the entire process in depth. The patent mentions several ways to minimize the amount of AN produced when dissolving the Cobalt. Since this patent seems involved to me, I'm going to go with a different approach. In my testing I'm going to try the various other mineral acids ( HCl and H2SO4) and possibly a basic organic acid (AA) if necessary.

I'll be experimenting with this topic very soon as I'm interested in the results myself.

Steve


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## Rusty2751 (Oct 24, 2007)

G'day All,

I have found that the simplest and cleanest way is to remove the substrate, not the metal coating from the HDD's. Put a batch of disks into a strong plastic pale and cover in one go with a strong solution of NaoH (Sodium hydroxide or lye), at least 50/50 with tap water.

Be careful of the very reactive exothermic reaction. The NaoH reacts with the aluminium substrate and gives off huge volumes of Hydrogen gas. *No naked flames.* The Aluminium is reduced to a sludge of Aluminium Hydroxide, a white powder when dry.

I leave the mixture to react overnight and then water it down with plenty of tap water and give it a good stir. The metal coating containing the Pt will settle on the bottom. Carefully pour off the top Aluminium Hydroxide layer and rinse the rest until it is clean. Then filter. If you leave it for to long and get clumps of white sludge just add 2:1 distilled water and Phosphoric acid to dissolve them.

If you like you can filter the dry the Aluminium Hydroxide liquor and let it dry. Mix this with some diluted Sulphuric acid and you then have Aluminium Sulphate which is an excellent flocculent for fine particles.

I'll add some pics shortly.

I hope that I haven’t raved on to much for my first post.

Regards
Rusty2751


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## lazersteve (Oct 24, 2007)

Rusty,

Welcome to the forum.

There are many methods to remove the foils effectively from the platters, the real question for me is which platters actually contain Platinum and how much? I think we all agree that the silver colored ones are the target platter group, but it is apparent to me from my tests that *not all* silver colored platter contain Platinum. I am currently working on identifying exactly which hard drive size ranges yield Platinum. It's useless to process every silver colored platter is only a small percentage of them contain Platinum. No matter the approach you will waste time and chemicals, plus you will end up with unnecessary by products.

The question of how much Platinum per platter is imperative to determine if the platters are actually worth processing at all.

Here's my most recent post on the HDD platter testing:

Platter Test Results

Steve


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## Anonymous (Apr 5, 2008)

Last night I was watching TV, talking on the phone and taking apart hard drives. When to my great suprize, I found a very old hard drive that has platters with Bright Gold that is right not a light shiny platter at all. This is a IMB hard drive. So did they ever use gold on hard drives. This is a new one on me. Looks the color of 10C or 12C gold. But it could be anything.


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## lazersteve (Apr 5, 2008)

It's most likely iron oxide. 

Steve


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