Financement et collaboration : COFUND DOC2AMU
Date de début de thèse : octobre 2018
Keywords : critical raw elements, waste valorization, bauxite residue, microbial fuell cells, pythoextraction
Abstract : Critical raw elements (CRE), including rare earths elements (REE) and platinoids, are at the heart of many emerging technologies such as smartphones, automobiles and low-carbon energy technologies. Nowadays, the main problem regarding CREs is a potential supply difficulty due to their low concentrations in ores as well as their unequal distribution in the world. The criticality of these materials is pushing industry and research to optimize recovery and recycle from secondary sources, including pre-consumer manufacturing residues; end-of-life products (urban mining); and landfilled mining of urban and industrial waste residues. Classical recycling techniques involve the use of important quantities of acid and basic solvents, which have proved to be not only unselective but also harmful to the environment.
Consequently, the project aims at developing bio-extraction processes alternative to more traditional pyro- and hydrometallurgy methods. To fulfil this objective, the first step of the project will be the fine characterization of a selected waste and the speciation of the strategic elements present in it to better optimize the bio-extraction processes. The waste to be studied will be bauxite residue, a by-product of the alumina extraction that is produced in Gardanne by Alteo. Based on these results, CREs will be recovered from waste by either microbial fuel cells built on a library of bacterial strains able to extract CREs, or via phytoextraction processes by using root-associated bacteria that increase CREs uptake by plants.