Tailored lixiviant delivers high-performance separation and recovery of heavy REEs from mine tailings concentrate

CMI Highlight: Tailored lixiviant delivers high-performance separation and recovery of heavy REEs from mine tailings concentrate

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

Innovation 
Integrating REE leaching and group separation into one step utilizing a heavy REE-selective lixiviant.

Achievement

  • Delivered ~97% HREE recovery from an industry RE(OH)3 feedstock derived from Pea Ridge iron mine tailings
  • Achieved 89% HREE-enriched leachate and 97% LREE-enriched solids 
  • Leachate purity can be further improved with increased mass loading

Significance and Impact

  • Single-step, highly selective, all-aqueous leaching that effectively splits HREEs (Gd-Lu, Y) and LREEs (La-Eu)
  • Strong dual enrichment lowers downstream separation burden and boosts overall efficiency

Hub Target Addressed
Unlocking unconventional resources; highly selective separation from complex sources; intra-REE separation.

Selective leaching of REEs from an authentic mixed feedstock. Top: Feedstock profile. Middle: Leachate composition after 12 d mixing. Bottom: Composition of residual solid.
Selective leaching of REEs from an authentic mixed feedstock. Top: Feedstock profile. Middle: Leachate composition after 12 d mixing. Bottom: Composition of residual solid.