An integrated cross-scale computational approach for understanding and optimizing continuous-flow extraction of precious metals

The extraction of platinum group metals (PGMs) from secondary resources is essential for sustainable resource cycles, yet process design often relies on empirical methods due to a lack of multiscale understanding. This study develops an integrated computational framework combining Molecular Dynamics (MD) and Computational Fluid Dynamics (CFD) to systematically investigate and optimize continuous-flow palladium (Pd) extraction. MD simulations clarify atomic-scale interactions, revealing strong coordinative bonding between Pd ions and the sulfur atoms of diisoamyl sulfide (the extractant), and quantifying transport properties such as viscosity and thermal conductivity in the organic phase. CFD modeling reveals how flow regimes and vortex dynamics in a heart-shaped microchannel govern phase mixing and interfacial contact—key factors controlling extraction efficiency. By linking molecular selectivity to device-scale hydrodynamics, this cross-scale approach demonstrates that efficient recovery requires both selective extractants and intensified mixing conditions. The approach provides a rational tool for co-optimizing ligand design and process parameters, advancing the development of sustainable precious metal recycling technologies.