『Abstract
The role of (Al,Si) disorder in the kinetics of albite dissolution
is explored through parameterized Monte Carlo methods. Two dissolution
mechanisms−multilayer leaching and single-layer retreat−were tested
on 48 albite test configurations. In simulations involving multilayer
leaching, dissolution rates increased with decreasing long-range
order (LRO). We observed a fivefold maximum increase in dissolution
rate tied to (Al,Si) disordering, roughly equivalent to that accompanying
a decrease of 1.4pH units at pH 1-5. This increase in rate due
to disordering in albite is similar to that observed from compositional
variation in plagioclase feldspars (An47 vs. An0) at low pH. In
contrast, (Al,Si) disordering had no discernible effect during
the simulations involving the single-layer retreat mechanism.
These results suggest that the effect of (Al,Si) disorder on albite
dissolution rate is mechanism-dependent.
Keywords: Long-range order; short-range order; disorder;
albite; Monte Carlo; dissolution mechanism; kinetics』
Introduction
Definitions of LRO and SRO
Computer modeling
Al,Si distributions with different LRO
Minimization of SRO
Dissolution modeling
Visualization of site ordering: A 2D projection model
Results and discussion
Configurations
Role of oeder/disorder in albite dissolution
Acknowlwdgmenta
References cited