Phosphoric acid sludge a potential source of rare earths

Bench-scale, continuous-flow decanter centrifuge used to continuously recover high-quality phosphoric acid and rare-earths containing solids
Bench-scale, continuous-flow decanter centrifuge used to continuously recover high-quality phosphoric acid  and rare-earths containing solids 

CMI researchers at Oak Ridge National Laboratory and the Florida Industrial and Phosphate Research Institute (FIPR Institute)conducted the activity for this highlight

Innovation 
Continuous-flow decanter centrifuge effectively separates rare-earths (RE) containing solids and high-quality phosphoric acid (PA) for economic viability

Achievement
Effective solid/liquid separation was demonstrated using a decanter centrifuge. Mass balance over single-pass continuous-flow demonstrated over 95% recovery of PA liquid and over 87% recovery of RE-containing solids from a feed of 33.5 wt.% solids-containing PA sludge. 

Significance and Impact

  • Achievement ensures economic viability for RE recovery from PA sludge
  • Expected to lead to an industrially relevant RE recovery process
  • The separation process will be further optimized for longer operation and post-treatment for the recovery of phosphorus and RE 

Hub Target Addressed 

  • Unlocking unconventional resources
  • Recovery and conversion into high-value end products
Bench-scale, continuous-flow decanter centrifuge used to continuously recover high-quality phosphoric acid and rare-earths containing solids