Coupling µXRD/µXRF/µXAS measurements for a detailed study of light rare earth element speciation in complex mining and industrial wastes.

Driven by the world's growing population and rapid economic growth, the pressure on natural resources is exponentially increasing. It is the case for critical metals, including Rare Earth Elements (REEs), that are the heart of a number of strategic technologies for the environmental transition. In the context of a circular economy, the exploitation of secondary resources such as complex mining and industrial wastes for the production of REEs seems to be a viable solution, but it requires a fine characterization of the materials, including metal speciation, in order to identify their potential and explore new metallurgical systems based on selectivity. We propose here to specifically investigate the microscale speciation of light REEs (La, Ce, Pr, Nd), in various mining and industrial waste materials, by coupling µXRD measurement (ID13) to µXRF/µXAS (ID21).