Experimental thermodynamics of rare earth element kozoites

CMI researchers at Arizona State University conducted the activity for highlight

Innovation

Synthesis and thermochemistry of REE carbonates (REECO₃OH). Evaluation of structural and thermodynamic properties through experimental measurements and extrapolation to endmembers which could not be directly synthesized.

Achievement

Enthalpies of formation of REECO₃OH (from oxides) have been determined using room temperature acid calorimetry.

Significance and Impact

Carbonates are major REE ore minerals, understanding their thermodynamic stability is essential for modeling and application
Understanding the thermodynamic properties of carbonate phases, such as kozoite, helps model the phase fractionation and mobility of REEs during ore mineral formation. This can lead to better models for geologists searching for new domestic REE deposits.

Hub Target Addressed

Developing and applying scientific tools to accelerate technology maturation.

plot graph with downward trending line — Enthalpies of formation (from oxides) are plotted against ionic radius at standard state and 298.15 K showing a linear trend for the lanthanides with a potential variance for Y, an element with fewer electrons.