![images depict three ligands on bastnäsite-[100] with explicit solvation Bottom: Comparison of a ligand’s methyl orientation angle as measured by SFG spectra and predicted by DFT simulation for a studied ligand](/sites/default/files/styles/large/public/inline-images/cmi-highlight-360.png?itok=_sHu0pp6)
Bottom: Comparison of a ligand’s methyl orientation angle as measured by SFG spectra and predicted by DFT simulation for a studied ligand
CMI researchers at Oak Ridge National Laboratory conducted the activity for this highlight
Innovation 
A combined theoretical and spectroscopic approach provides unprecedented insight into how hydroxamic acid-based ligands behave at the molecular level as collectors for selective froth flotation in rare earth ore beneficiation.
Achievement
- Demonstrated strong, selective binding of a novel ligand containing two hydroxamic acid groups on the predominant bastnäsite crystal facet.
 - Provided meaningful insight into molecular recognition of bastnäsite vs calcite with five hydroxamic acid-based collectors and elucidated the role of water molecules.
 
Significance and impact
- Over a billion tonnes of minerals are concentrated by flotation each year, but poor understanding stands in the way of reducing losses, waste, and energy consumption.
 - Highly selective collectors for rare earth minerals are key to improved flotation.
 - Explicit solvation is shown to be essential in density functional theory calculations of hydroxaminc acid adsorption mechanisms, leading to improved prediction.
 - Observed molecular recognition behavior can help guide the design of future collectors.
 
Hub Target Addressed 
Highly selective separation from complex sources.