The physicochemistry of hydrometallurgical processes for metal production is complex because they rely on the description of phases in which many equilibria occur and because important efforts still have to be done to develop thermodynamic models for describing these equilibria. Furthermore, more thermodynamic data must be acquired as too few data are available under relevant conditions for hydrometallurgy are available.
Many challenges remain to be overcome to achieve a fine description of the solid phases (resins, precipitates, crude, colloids) and liquid phases (aqueous phase, organic phase, ionic liquids) as well as mass transfer at interfaces. This issue concerns both existing and new systems. The development of rational approach based on a fine description of the physicochemistry and the thermodynamics involved in hydrometallurgical processes is then good way to improve them and to easily transpose studies conducted at the laboratory scale to industrial scale.
For this goal, it is therefore essential to achieve a fine description of speciation in aqueous phases and organic phases usually used in hydrometallurgica processes. In particular, the supramolecular organization of extraction solvents must be thoroughly investigated by means of modern experimental tools such as SAXS and SANS, and more conventional techniques used in colloid chemistry. In addition, experimental data must be compared with modeling results at different scales, from the molecular to mesoscopic scale, thanks to molecular dynamics techniques, emphasizing the development of models describing the non-ideality of the aqueous and organic phases. The phenomena occurring at the liquid-liquid interface for solvent extraction processes and solid-liquid interface for separation processes based on the use of resins is another topic discussed in this WG. The study of these interfaces requires the establishment of complex experimental techniques such as the NMR gradient field, or the use of second harmonics generation of pulsed laser or X-ray or neutron reflexivity.
