Battery recycling is now a major geopolitical, economic and environmental issue for the EU. Graphite, which makes up the anode of Li-ion batteries, is very rarely recycled. It is concentrated in a fraction called blackmass, where it is mixed with metal oxides of high commercial value. This graphite is then considered as an impurity and causes oversizing of hydrometallurgical operations. Since natural graphite is considered critical by EU and in order to reduce the operating and investment costs of hydrometallurgical processes, it is proposed to carry out a pre-treatment step on the blackmass in order to valorize the graphite directly. This stage is carried out by flotation. This process for separating solids suspended in water uses gas in the form of air bubbles to separate the particles according to their difference in wettability and therefore their attachment to the air bubbles. The complexity of the flotation process, linked to the dependence on both the nature of the interfaces and the hydrodynamic conditions, requires in-depth understanding of the mechanisms involved.
The aim of the proposed project, which follows on from two internal projects, is to identify the mechanisms at work during flotation, using methods of interfaces characterization, stability and rheology of foam fraction, imaging, etc., with a view to improving the performance of the flotation stage and extending it to other recycling challenges.
The PhD thesis work will be carried out at the Laboratoire des technologies de Valorisation des procédés et des Matériaux pour les ENR (LVME) at CEA Grenoble and in close collaboration with the Laboratoire de Caractérisations Avancées pour l'Energie (LCAE) at CEA Grenoble, the Laboratoire des Procédés Supercritiques et décontamination (LPSD) and the Laboratoire de développement des procédés de recyclage et valorisation pour les systèmes énergétiques décarbonnés (LRVE) at CEA Marcoule (30). In parallel with the experimental work, the models and mechanisms involved and the associated technical solutions will have to be proposed.
The scientific and industrial interest of the subject guarantees that the work will be promoted through international communications. After the PhD, you can join one of the best academic or applied research teams, or pursue an R&D career directly in industry.