Application of Eh-pH Diagrams on Acid Leaching Systems for the Recovery of REEs from Bastnaesite, Monazite and Xenotime

Bastnaesite, monazite and xenotime are rare earth minerals (REMs) that typical sources for elements (REEs). To advance the understanding of their leaching precipitation behavior in different hydrometallurgical processes, Eh-pH diagrams were constructed modified using HSC 9.9 software. The aqueous stability H2O acid systems, i.e., REE-Ligands-H2O depicted studied based on diagrams. This study considers most relevant lixiviants, resulting equilibrium states importance recovery (REMs). A literature review was performed summarizing associated thermodynamic data. Shifting regions REEs discovered with additions ligands a narrow region soluble REE-(SO4/Cl/NO3) complexes under highly acidic conditions. As such, can be enhanced by adjusting pH Eh values. In addition, major contaminants (i.e., Fe, Ca Al) systems studied. provide possible insights into potential passivation particle surfaces due to formation an insoluble product layer.