Competitive anion coordination: lattice destabilisation and vanadium release from vanadium-bearing muscovite across multiple crystallographic surfaces

Vanadium release from vanadium-bearing muscovite is strongly constrained by the rigid T-O-T aluminosilicate lattice and competitive interactions among lixiviant-derived anions. Herein, the competitive anion-assisted lattice destabilisation mechanism was resolved across multiple crystallographic interfaces of muscovite, including the (0 0 1) basal surface, exposed octahedral (0 0 1) layer, and (0 1 0) edge surface. Macroscopic leaching kinetics showed that HF followed an internal diffusion-controlled mechanism with the lowest apparent activation energy of 28.95 kJ mol −1 over 10–60 min, whereas H 2 SO 4 , HCl, and H 2 C 2 O 4 were dominated by surface chemical reaction control, with higher activation energies of 31.04 ∼ 40.23 kJ mol −1 . Molecular dynamics simulations revealed that F − exhibited the highest self-diffusion coefficient on all muscovite surfaces, following the order F − > Cl − > HC 2 O 4 − > HSO 4 − , with the (0 1 0) edge serving as the most favourable transport pathway. Density functional theory calculations showed that F − possessed the strongest on-top adsorption and the most pronounced preference for V-centred sites, whereas bridge adsorption was geometrically accessible only to HSO 4 − and HC 2 O 4 − . Multisurface analysis identified two anion-access pathways: sterically restricted basal adsorption/trapping through the (0 0 1) basal/exposed-octahedral direction and edge-accessible coordination through the (0 1 0)/(1 0 0) surfaces. Oxygen-site substitution calculations further demonstrated that F − induced the smallest lattice distortion and the most favourable substitution energies of −8.06, −8.08, and −8.11 eV from (n = 1) to (n = 3), respectively. Projected density of states analysis revealed direct V 3d–F 2p electronic coupling and redistribution of V–O-related electronic states after F − substitution. These results indicate that fluoride dominance originates from the synergistic coupling of rapid interfacial diffusion, V-selective adsorption, edge-accessible coordination, favourable oxygen-site substitution, electronic redistribution, and V–O coordination destabilisation. This work provides mechanistic guidance for evaluating competitive anion effects and designing efficient anion-assisted lixiviant systems for refractory vanadium-bearing aluminosilicates.