Data Centre

Is your old hardware made of gold, or just DIRT?

Why it's not worth much, unless it's really old

Must get away from Chinese rare earths! Who here's willing to pull old hard drives apart for 25 cents a go? Well, the Chinese might ...

Much has been muttered about electronics and rare earths recently what with China playing silly buggers with supplies but here we're definitely on the dirt side of the equation. Neodymium is essential for the magnets in a hard drive motor: well, not essential, but the alternatives are more expensive and larger. However, there's some 6 grammes in each hard drive, meaning that you'd need to process 1 million hard drives to get 6 tonnes of the metal (and it's actually 6 tonnes of NdFeB magnet, not pure metal). At non-bubble prices of $40 a kg this doesn't really seem worth it: Anyone really want to hand pull (which you'd almost certainly have to do) a hard drive apart for maybe 25 cents a time? Yes, this is the dirt side of our barrier.

Metal Wires. Credit: UNEP

Ore, or ... ?

We've just had a report out about all of this, the recycling of metals in Europe. The report is here and it's rather good. It must be for it makes similar points to me. The reports about the report though are awful:




No, that's nonsense. For reasons that the report itself points out: we recycle where it is economic to do so and do not where it isn't. Or to use my language, when the scrap is dirt we don't and when it's ore we do.

Take two metals, rhenium and terbium. They're both worth around $5,000 per kg, or at least they both have been recently, even if they're not that price today. We recycle most rhenium we use and almost none of the terbium we use. Re is used in jet engines, along with nickel and cobalt. Come the end of the jet engine's life, we've three nice valuable materials and we dissolve the lot and separate it all to make new alloy. We're also scrapping our jet engines in nice centralised locations so we accumulate the stuff. The other use is alloys with platinum in oil refineries and yes, of course we recycle that stuff.

Terbium however is used for phosphors on CRTs and in compact fluorescent light bulbs. We're talking milligrammes per light bulb so we're back to wanting a million bulbs to get our kg worth perhaps $5,000. And the bulbs mustn't break or the Tb will be lost to the environment. Tb's Clarke number (prevalence in the Earth's crust) is 1.1 or so, meaning 1.1 parts per million. Our pile of lightbulbs isn't all that far away from the Tb concentration of the vegetable patch which is why we tend not to mine either for Tb. Rare earth ores (not rare, as we all know) can be 0.09% by weight to 0.9% by weight Tb, orders of magnitude higher than the lightbulbs and thus we get our Tb where it's easy and cheap, not from recycling.

Even metals that we think we really are seriously short of we don't recycle if our use of them is to disperse them. Tellurium really is rare, 0.001 ppm in the crust, and we use it to make solar cells of the First Solar type, Cd/Te. But we don't recycle the cells, not even the factory failures, for the Te content. That content is so low that it is still cheaper to go and process some more copper slimes (no, really, proper technical word!) and no, we're still not going to run out of the metal. For everyone forgets just how big the Earth actually is. Six times 10 to the 24 kg, some 2% of it is crust. At 0.001ppm Te in the crust, we've still got 120 million tonnes of Te and we're using 125 tonnes a year. Chuck it mate and get some new in.

But all of this, while interesting, isn't telling you guardians of the hardware how to pay for the Christmas party is it? I'm afraid that for your standard kit your WEEE compliant contractors are still going to charge you for hauling it away. Yes, much of it does get recycled and the metals extracted, but that's because the law says they must. The process as a whole costs more than the metals value extracted which is why you've got to pay the difference: although do make sure your contractor is giving you a credit for that reclaimed value.

Three other things you can do though: nick everyone's smartphone and sell it to the people advertising on the TV (as with all such things, if you've got a bucketful, you'll get a higher price for each). If you're not already doing it you should be selling your empty printer cartridges. Yes, they can be valuable and bucketsful of them ditto.

Or, finally, have a rootle around in the back cupboards and see if you've got any really old kit. Hard Drives for PDP 11s for example, they were made of AlNiCo magnets, great girt lumps they were. Many a scrap dealer will take those off your hands for readies. Did someone buy in a stock of 8087s at some point and they're still rotting long after the last XT has left the building? And anyone out there with an analogue telephone exchange can have his choice of new digital ones for the gold content.

Entirely happy to help anyone with old kit or cartridges: the phones you'll have to fence on your own. ®

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