Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.768283
Title: The use of hydrogen to extract NdFeB magnets and REES from assemblies
Author: Jönsson, Christian Tobias
ISNI:       0000 0004 7653 3583
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2018
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Restricted access.
Access from Institution:
Abstract:
Recycling of end-of-life NdFeB magnet could provide a sustainable supply of the critical elements Nd and Dy. These are found in waste streams of electronic and electric equipment (WEEE) and drive motors of electric vehicles. Hard disk drives have been identified as an ideal recycling candidate, and a promising process has been developed at the University of Birmingham, called HPMS, which uses hydrogen to extract NdFeB in the form of a demagnetized hydrogenated powder. This thesis has identified loudspeakers from laptops and flat screens to have a good recycling potential. They are all coated with Zn meaning that HPMS should be fully applicable. The HPMS process was then successfully applied to large automotive rotors, extracting more than 95% of the NdFeB. However, it was shown that rotor magnets react slower due to the higher Dy content and lower REE content, meaning that higher pressures might be needed. The hydrogenated powder was disproportionated at high temperature in hydrogen to create large spheres of NdH2 in the Fe matrix, opening up for physical separation of NdH2 from NdFeB. The oxidation of various hydrogen-processed powders was also studied, showing that hydrogenation is beneficial for roasting which is used in the pyrometallurgical recycling flowsheet.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.768283  DOI: Not available
Keywords: TK Electrical engineering. Electronics Nuclear engineering ; TP Chemical technology
Share: