(694e) Pore-Scale Study of the Effect of Precipitate On Dissolution Using Lattice Boltzmann Method

A mesoscopic model based on the lattice Boltzmann method (LBM) is developed to investigate the effects of secondary precipitate on the dissolution of primary solid phase. The model can predict coupled multiple physicochemical processes including fluid flow, mass transport, chemical reaction, dissolution, precipitation consisting of nucleation and crystal growth, as well as dynamical evolutions of pore geometries. Effects of dissolution and precipitation reaction kinetics, molar volumes of primary and secondary solid phases, initial powder size and surface roughness of the primary solid phase, as well as nucleation and crystal growth mechanisms on the dissolution and precipitation processes are investigated in terms of rate and amount of dissolution and precipitation. Several types of dissolution and precipitation processes are identified based on the morphology and structures of the precipitates and the extent the precipitates affect the dissolution of the primary solid phase. Simulation results are also compared with existing experimental results. Depending on the conditions, the precipitates are found to have trivial, favorable or detrimental effects on the dissolution of the primary phase.