Advanced leaching of Cu-Zn, Zn-Pb and Cu-Zn-Pb tailings using microwave heating

This Ph.D. is part of the H2020-MSCA-ETN project SULTAN (grant agreement number 812580). The aim of the PhD project is to develop advanced metal extraction processes with the usage of microwaves (MWs) to increase the selectivity, efficiency and kinetics of hydro- and solvometallurgical leaching systems for sulfidic tailings. The Ph.D. candidate will investigate the interactions of MWs with solid tailing materials (i.e. causing local crack formation, mineral transformation, increase of surface area, etc.) and within leaching processes in the presence of solvents or ionic liquids (ILs). The mechanisms of interaction of MWs with tailings, solvents and ILs are not fully understood but it is known that MW-assisted leaching is faster and allows significant reduction of required energy, solvent and reaction time with respect to conventional heating. Thus, the foreseen milestones of the project are the development of MW-assisted leaching process with >15% energy saving, increased leaching efficiency (> 95% for base metals (Cu, Pb, Zn) and > 85% for trace metals (e.g. In, Ga, Ge, Ag, Au)) and selectivity, as well as >15% solvent/reagent saving and >50% shorter leaching times with respect to conventional heated leaching processes of sulfidic Cu-Zn, Zn-Pb and Cu-Zn-Pb tailings. The project consists of the following tasks: 1. Mineral characterisation: tailings characterisation through chemical and mineralogical analyses and selection of the most suitable leaching systems by means of literature study and thermodynamic modelling 2. MWs impact: investigation of the impact of MWs on the structure and the morphology of the tailing materials by means of optical and Raman microscopy, SEM, XRD and BET 3. Microwave leaching: development of MW leaching processes for the selective recovery of metals from tailings in solvent-based systems, ionic liquid based systems and deep eutectic solvent (DES) based systems.