New process of re­cy­cling rare earth mag­nets

Chemical Industry Digest - - New Developments -

Re­searchers from the U.S. De­part­ment of En­ergy’s Crit­i­cal Ma­te­ri­als In­sti­tute (CMI) have cre­ated a new re­cy­cling process that turns old hard disk drive (HDD) mag­nets into a brand-new mag­net ma­te­rial with just a few steps. This new process over­comes eco­nomic and en­vi­ron­men­tal prob­lems that have plagued e-waste min­ing for valu­able ma­te­ri­als for years.

The CMI re­searchers thought that it was im­por­tant to fo­cus on e-waste be­cause one of the most abun­dant sources of rare earth mag­nets is hard disk drives that are thrown away all the time. “There are a lot of ways to go about get­ting the rare-earth el­e­ments out of e-waste, and some of them are very ef­fec­tive, but some cre­ate un­wanted by-prod­ucts and the re­cov­ered el­e­ments still need to be in­cor­po­rated into a new ap­pli­ca­tion,” said Ryan Ott, Ames Lab­o­ra­tory sci­en­tist and mem­ber of the CMI re­search team. “Here we have elim­i­nated as many pro­cess­ing steps as we can, and go straight from the dis­carded mag­net to an end prod­uct, which is a new mag­net.”

In this new process, the dis­carded HDD mag­nets are col­lected and any pro­tec­tive coat­ings are re­moved. The mag­nets are then crushed into a pow­der that is put into a sub­strate with a plasma spray. This plasma spray syn­the­sizes the coat­ings to 0.5 to 1 mm thick. The new mag­net ma­te­rial can’t re­tain the same mag­netic prop­er­ties as the orig­i­nal ma­te­rial. De­spite this, the new mag­net still gives the mar­ket an eco­nom­i­cal choice in an area where a high-per­for­mance earth mag­net isn’t needed but lower-per­for­mance mag­nets like fer­rites won’t work. “This waste re­duc­tion as­pect of this process is re­ally two-fold; we’re not only reusing end-oflife mag­nets but we are also re­duc­ing the amount of man­u­fac­tur­ing waste pro­duced in mak­ing thin and small ge­om­e­try mag­nets out of larger bulk ma­te­ri­als,” added Ott.

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