Rare earth metal separation with new amide functionalised ionic liquids
: Understanding species and selectivity

  • Ciaran Carroll

Student thesis: Doctoral ThesisDoctor of Philosophy


Recycling rare-earth metals from end-of-life products such as hard-drive magnets is of critical importance particularly in the face of growing demand for consumer goods and other applications. Liquid-liquid extraction is the preferred method of separation utilising organic extractants owing to their scalability and commercial potential. The use of volatile diluents is a major safety concern in these large separation processes. Task-specific ionic liquids have been developed in response, benefiting from their negligible vapour pressure offering an alternative for liquid-liquid rare-earth metal separation.

The work presented in this thesis aimed to develop the multifunctional amide ionic liquid, [MAIL][NTf2], for extraction of rare-earth metals from waste magnet feeds, specifically separation of dysprosium(III) and neodymium(III). In addition to designing and synthesising new generations of extractants with the hope of developing superior extractants.

Thesis embargoed until 31 July 2025.
Date of AwardJul 2022
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsSeren Technologies Ltd
SupervisorPeter Nockemann (Supervisor) & John Holbrey (Supervisor)


  • Ionic liquids
  • rare-earth metals
  • lanthanides

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