Kinetics of gypsum dissolution in water

The kinetics of dissolution of different lithological varieties of gypsum was experimentally investigated at 5–25°C and P = 0.1 MPa, and a simple rate model was proposed on the basis of the sum of the rates of forward and backward reactions and proportionality to the activity product of calcium and sulfate ions. The activation energies of the forward reaction correspond to dissolution controlled by surface reaction kinetics. It was shown that the kinetic parameters of gypsum dissolution are invariant to the initial concentrations of NaCl solutions (up to 2 M). It was shown that the surface roughness factor (ξ) depends on the chemical composition of lithological varieties and the average grain size of gypsum and changes during epigenetic processes. The obtained kinetic parameters of gypsum dissolution in water will be used for the calculation of groundwater-driven mass transfer.