If you have ever wondered what kind of value is in the Hard Drive Platters then I have found the answer, finally.
I think this is based on '08 prices;
It's taken me just about forever, but I've finally found some way to answer the simple question "How much platinum is in these hard drive platters showing up on Ebay for salvage?" "The Chemistry of Computing" over at extremetech.com (article2/0,2845,1946290,00.asp) has all the facts: surface layer of Co-Cr-Pt alloy is 40-50% platinum, and the layer is ~30 nm thick. I don't have a hard drive platter in front of me, so let's just forget about the hole in the middle for a moment, so one platter from a 3.5" disk is 3.14*(3.5/2)^2=10.4 sq inches or 67.2 cm^2 ... times the 30 nm thickness (3x10^-6 cm) is 2.0x10-4 cm^3, times the (optimistic) 50% Pd, times the density of Pt (21.45 g/cm^3) and I estimate one platter has at most 2.2 mg Pt. As of 08/29/2008, the platinum spot price was 1470.00 USD per troy ounce, or more usefully, 4.73 cents per miligram. So, congratulations, you've just spent an hour of time and three cents of chemicals (just a guess, probably high) to reclaim 10 cents of platinum, probably still contaminated with cobalt and chromium depending on your recovery method. I hope you bought a whole bunch of platters cheap and rode a bike to pick them up because I doubt you'll be paying for gas let alone the shipping with the platinum. Or hope those early hard drives used a much thicker layer....
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I have argued and argued with people about the platinum content in hard drive platters for a long time now. I'm glad you found this on your own, and posted it yourself.
You see hard drive platters sell on ebay all the time, people are getting burned left and right. They are really only worth their aluminum content, the Pt is negligible. Not only that but it's only be fairly recently that platinum has been used as as a percentage of the plating on hard drive platters. So all the old hard drive platters don't even have platinum in the plating.
At the heart of science is an essential balance between two seemingly contradictory attitudes--an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense. -- Carl Sagan
Nice research Mech, so from what i gather people really are buying these platters for art projects and wind chimes . Also FYI not all platters have an aluminum base.
They also make great bird scarers. Using them as signalling devices, as long as the sun is shining
Good to see AJR back .......
I once used HCL acid to eat out the aluminium from the platter & the remaining 'chromeplate like' metal weighed 0.9grams.
Thast 0.36 grams Platnium per disc. Somethings wrong here............
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