Is it worth extracting Platinum from Hard Disc Drives?
The platinum group metals are Rhodium, Iridium, Palladium, Platinum, Ruthenium, and Osmium (PMG). Most of the time, these metals are taken from the same mineral deposits. They are some of the most valuable metals on earth.
In the past, Platinum was the most expensive metal to buy, but right now, Rhodium is the most expensive metal in the world.
One place you can find some of these metals is in the old mechanical hard disc drives. You will find these ubiquitous devices not just ion PC towers but laptops, satellite TV receivers, DVR boxes, and other such items which store data. Of course server racks and towers will be the gold mine of HD drives.
So is it worth trying to extract platinum from Hard Disc Drives? Spoiler alert – the answer is no.
Platters -what are they?
If you have broken up a hard disk drive, you will already know that there are a series of round ‘platers’ stacked on top of each other. They appear much like CD discs. It is here that the data is stored within small pockets of magnetic material.
Here’s a technical overview.
Each platter’s magnetic surface is broken up into small, sub-micrometer-sized magnetic regions. Each of these regions represents a single binary unit of information. As of 2006, a typical magnetic region on a hard-disk platter is 200–250 nanometers wide (in the direction of the platter’s radial axis) and 25–30 nanometers long (in the direction of the platter’s down-track axis), which is about 100 billion bits per square inch of disc area (15.5 Gbit/cm2). Most of the time, a cobalt-based alloy is used for the main magnetic medium layer. In modern hard drives, each of these magnetic regions is made up of a few hundred magnetic grains, which are the base material that gets magnetised.
How much Platinum is there in a disk drive?
There is really not a lot on the platters. Only a thin coating, microns thick. Then you have to factor ion how to get the stuff of. All this combined makes for a grim picture. Here a study from answers.com
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 (3×10^-6 cm) is 2.0×10-4 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.
https://www.answers.com/Q/How_much_platinum_in_a_hard_drive
Lets see a few videos on the topic. Moose scrapper has a great teardown video with some common sense advice.
Rob The Plumber also has a great video
But the best analysis comes from good old sreetips who definitively shows how futile platinum recovery is.
Conclusion
Microscrapping is great fun though often not economical. Certainly when it comes to Hard Disk Drives, may be focus on the aluminium, gold contacts and magnets, not on these super rare metals.