Beyond Bulk Grade: Mineral–Flow Accessibility Controls Pore-Scale Copper Recovery
Year: 2026
Type: preprint
Abstract: Mineral dissolution in porous media is driven by fluid flow, solute transport, and geochemical reactions, yet reactive transport models commonly use bulk mineral abundance and specific surface area as proxies for mineral reactivity. This neglects a key constraint: dissolution occurs only where reactants can access minerals through connected fluid-flow pathways. Here, we use pore-scale PFLOTRAN simulations of acid-driven chrysocolla dissolution to isolate the effect of mineral accessibility at fixed initial mineral volume fraction. Across pore-network ensembles and flow–reaction conditions, copper recovery varied substantially (9–21%) despite identical bulk copper content. Recovery depended on the fraction of mineral accessible to connected flow and on mineral proximity to inlet-connected pores, even when cumulative pore volumes flushed during the 48 h acid pulse were nearly identical. In contrast, Péclet and Damköhler numbers characterized transport–reaction regimes but did not uniquely predict copper recovery because they do not encode pore-scale accessibility. An accessibility-weighted pore-volume metric combined with intrinsic dissolution kinetics explained recovery with R2 ≈ 0.95. Thus, our results show that mineral–flow accessibility and reaction kinetics jointly control pore-scale copper recovery and provide a physically interpretable basis for accessibility-aware reactive transport upscaling.
Source: ChemRxiv
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221434666