Understanding the behavior of metals in complex systems (liquids and/or solids) is at the heart of the development of efficient hydrometallurgical processes for recycling and waste management. The approaches developed are mostly aimed at the control of unitary steps, by liquid or solid route. The team proposes to integrate all these developments into global extraction-separation-final material sequences, under the concept of circular separative chemistry. This simplification of the processes aims at a better management of the mixtures, a better flexibility in front of a raw material of variable composition, a reduction of the number of stages, generally synonymous with a control of the generated effluents. Moreover, the notion of recycling is not restricted to the isolation of a purified metal or element, and the team takes into account the material end: the processes developed integrate as well as possible the valorization of the targeted metal in the form of finished product, for a similar or different application, with a particular interest for its shaping.
The studies carried out in the laboratory are mainly focused on the description and understanding of the properties of molecular and supramolecular systems based on metals (d and f). The aim is to determine the role of interactions between a metal center and its near and far environment in a process of organization of matter, then to take advantage of this organization to form either complex organic phases specific to a metal, or specific assemblies such as coordination polymers. In this framework, the team does not seek to develop new tools (new molecules, new solids, new synthesis methodologies), while possessing a perfect mastery of existing tools, including mechanistic aspects at the molecular level. The systems thus studied aim at developing innovative separation processes, two- or three-phase, targeting various metals of interest with different physicochemical properties (valence, charge density...) such as transition metals (Pd, Au, Ni, Co, Mn, Ru, Al, Sc), lanthanides or actinides (U, Th and Pu). These systems are then used for the development of short circuits (open or closed), in various fields treated at the ICSM. At the level of the nuclear fuel cycle, the studies carried out aim at the simplification of a closed cycle driven by safety, thanks to a controlled management of actinide mixtures.
This approach integrates the fine material aspect by the direct and controlled preparation of actinide materials, pure or in mixture, organized at the nanometric scale. In the waste and recycling industry, the developed approach aims at improving the value chain by the direct preparation, without purification, of high added value compounds, taking into account the economic and ecological models. Various applications are addressed, thanks to an established network of academic and industrial collaborations: in open cycle such as the synthesis of materials for depollution from battery waste, the preparation of catalysts (Pd, Au or Ni) from electronic or industrial waste containing precious metals; in closed cycle within the framework of the development of precursors of materials for energy storage.
