Kinetic Monte Carlo as a bridge between nano- and macroscales: a case study on dissolution of (Ba,Sr,Ra)SO4 solid solution
Authors: Trofimov Nikolai , Kurganskaya Inna , Luttge Andreas 
Published: March 2024

Barite (BaSO4) is a common rock-forming mineral, controlling barium behavior in Earth&#8217;s crust and marine water. This mineral can incorporate Sr and Ra into the crystal lattice by forming binary and ternary solid solutions. It makes barite a promising material for use in nuclear storages e.g., for nuclear waste containers. The achievement of high levels of safety in modern nuclear waste deposits requires studies on container&#8217;s material-water interaction. The data on solid-liquid interface reactions can be obtained by both experimental and computational methods. The most widespread experimental methods for studying surface reaction kinetics are Atomic Force Microscopy (Putnis, 1995; Bosbach, 1998; Risthaus, 2001; Kuwahara, 2011) and Vertical Scanning Interferometry (Luttge, 2010). However, these methods do not provide information on reaction mechanisms at the molecular scale. Approaches such as Density Functional Theory and Molecular Dynamics give detailed information of the reaction mechanisms at the nano-scale but are limited by the computational costs, system size, and reactions time period (Kurganskaya et al., 2022). Kinetic Monte Carlo is a stochastic approach, which can be successfully used as a connecting link between molecular and macroscopic scales, incorporating both experimental (AFM, VSI) and computational (DFT, MD) data. The KMC model of pure barite dissolution in water was developed by Kurganskaya et al., 2022. We present a new Kinetic Monte Carlo model of mineral-water dissolution in (Ba,Sr,Ra)SO4 system and discuss the general approaches for KMC models parameterization, based on a crystal chemistry of studied material.Putnis, A., Junta-Rosso, J. L., &amp; Hochella Jr, M. F. (1995). Dissolution of barite by a chelating ligand: An atomic force microscopy study.&#160;Geochimica et Cosmochimica Acta,&#160;59(22), 4623-4632.Bosbach, D., Hall, C., &amp; Putnis, A. (1998). Mineral precipitation and dissolution in aqueous solution: in-situ microscopic observations on barite (001) with atomic force microscopy.&#160;Chemical Geology,&#160;151(1-4), 143-160.Risthaus, P., Bosbach, D., Becker, U., &amp; Putnis, A. (2001). Barite scale formation and dissolution at high ionic strength studied with atomic force microscopy.&#160;Colloids and Surfaces A: Physicochemical and Engineering Aspects,&#160;191(3), 201-214.Kuwahara, Y. (2011). In situ Atomic Force Microscopy study of dissolution of the barite (0 0 1) surface in water at 30&#176; C.&#160;Geochimica et Cosmochimica Acta,&#160;75(1), 41-51.Luttge, A., &amp; Arvidson, R. S. (2010). Reactions at surfaces: a new approach integrating interferometry and kinetic simulations.&#160;Journal of the American Ceramic Society,&#160;93(11), 3519-3530.Kurganskaya, I., Rohlfs, R. D., &amp; Luttge, A. (2023). Multi-scale modeling of crystal-fluid interactions: state-of-the-art, challenges and prospects.Kurganskaya, I., Trofimov, N., &amp; Luttge, A. (2022). A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry.&#160;Minerals,&#160;12(5), 639.