A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry

Barite (Ba[SO4]) is one of the promising candidates for sequestration radioactive waste. can incorporate radium (Ra) and form ideal solid solutions, i.e., (Ba,Ra)[SO4]. Together with isostructural celestite (Sr[SO4]), ternary (Ba,Sr,Ra)[SO4], may exist in natural conditions. Our fundamental understanding dissolution kinetics sulfates critically important a better risk assessment nuclear waste repositories utilizing this mineral sequestration. So far, barite-water interface has been studied experimental methods atomistic computer simulations. The direct connection between molecular scale details structure observations at microscopic not yet well understood. Here, we began to investigate by using kinetic Monte Carlo approach simulate barite process. We constructed microkinetic model process identified reactive sites. Identification these sites an improved dissolution, adsorption, crystal growth mechanisms barite–water interface. parameterized detachment rates experimentally observed etch pit morphologies atomic step velocities. parameterization attempts demonstrated that local lattice coordination sufficient differentiate kinetically estimate their rates. suggest water dynamics should substantially influence However, it will require more work improve means Molecular Dynamics ab initio calculations.