Leaching and bioleaching
This topic focuses on leaching and bleaching. These two approaches are often complementary to the recovery of metals, especially depending on the refractory nature of the ores. Leaching can not be considered without taking into account the upstream processes - for example, the creation of selective micro-fracturing of fragmentation during ore processing have a direct impact on the leaching or the species in solution from the leaching stage can be more or less favorable to the phases downstream refining and separation. Bio-hydrometallurgical processes are an industrial reality for the production of copper and gold. Bioleaching heap is now a viable method of recovery of copper, with an established place in the metallurgical industry. Bioleaching reactors is often used to treat refractory sulfide ores that contain gold, upstream of cyanide leaching. These commercial successes are encouraging, but (i) are applied to the processing of very specific resources, (ii) use a relatively small range of microorganisms and (iii) are limited to a few technology options. In addition, a challenge for biohydrometallurgy is the treatment of resources to which are difficult to valorize, such as complex polymetallic concentrates, ores and concentrates low, and various oxides.
Several points can be studied in this WG :
The formation of surface layers on materials, natural or waste, during leaching is a phenomenon which considerably impairs the efficiency of leaching processes and bioleaching . In connection with the above phenomenon, modeling the kinetics of equilibria also represents a significant challenge, firstly because of the lack of experimental data on the limiting steps of dissolution, secondly because of the complexity of the mechanisms related to the formation of inhomogeneous and often porous surface layers. The classical core-shell kinetic models must be revisited to reproduce the phenomena of interest.
