The complexity of silicate minerals makes prediction of their dissolution rates a challenging problem. A combination of large cluster ab-initio quantum mechanical models and chemical probe dissolution experiments are used to understand the dissolution process for olivine-group minerals. Rapid release of M2+ cations by precursor reactions involving H+ attack at μ3-O surface sites produces a silica-enriched surface. Slower rates of silica release via a ligand exchange reaction involving a proton in the activated complex controls the overall rate of olivine dissolution. Our results provide a physical explanation for the correlation among olivine dissolution rates and water exchange rates for the corresponding aqueous cation.
Keywords: Forsterite; dissolution rate; quantum mechanical model; ligand promoted; proton promoted』
FIGURE 1. Rates of forsterite dissolution.
〔Liu et al.(2006)による〔『Mechanism for the dissolution of olivine series minerals in acidic solutions』（455p）から〕