Enhanced REE separations using dual neutral extractant approach

Bank of 3D-printed centrifugal contactors used for the flowsheet demonstration at PNNL.

CMI researchers at Pacific Northwest National Laboratory and Oak Ridge National Laboratory conducted the research for this highlight

Innovation 
Developed a novel solvent‑extraction flowsheet for the selective separation of NdPr, SEG (Sm/Eu/Gd), and HREE, significantly reducing both the number of separation stages and the amount of reagent required.

Achievement
Early‑career PNNL scientists carried out monazite feed separation into HREE and LREE streams using a team‑designed bank of 3D‑printed centrifugal contactors for critical‑materials recovery.

Significance and Impact

  • Despite the high‑viscosity conditions caused by heavy HREE loading, the 3D‑printed centrifugal contactors delivered excellent hydraulics, cleanly separating HREE and LREE into their respective organic and aqueous streams with no detectable DGA‑6 loss to the raffinate.
  • Achieved effective HREE and LREE separation within seven stages, significantly reducing the required volumes of the organic solvent and aqueous acid.

Hub Target Addressed 
Developing processes to recover and separate REEs from traditional or unconventional sources.

Post‑baccalaureate fellow Dex Altavilla displays the HREE‑loaded organic product (left) and the LREE aqueous concentrate (right) produced during the centrifugal contactor run.
Post‑baccalaureate fellow Dex Altavilla displays the HREE‑loaded organic product (left) and the LREE aqueous concentrate (right) produced during the centrifugal contactor run.