Abstract
As a result of the analysis of data from literature sources, the average values of the reaction rate constant for the dissolution of gypsum in water (kav = 1.48 × 10–5 mmol/(cm2 s, 25°C) and activation energy ( \(E_{{{\text{av}}}}^{1}\) = 39 kJ/mol), characteristic of kinetic and diffusion-kinetic control conditions, were determined. The calculated temperature dependence follows the Arrhenius equation in the range 0–40°C (log kav = 1.95–2021/T, К). An increase in solution temperature (T > 40°C) causes diffusion inhibition of heterogeneous chemical reactions of gypsum dissolution. It is assumed that at T ≈ 40–42°C the boundary between the macrokinetic regions of gypsum dissolution in water corresponds to the zone of temperature transition between the equilibrium state of gypsum and anhydrite (CaSO4⋅2H2Os– \({\text{CaSO}}_{4}^{{\text{s}}}\) –H2O; P = 0.1 MPa). It is proposed that a similar transition in electrolyte solutions should also be determined taking the diffusion resistance of the rate of chemical interactions on the reaction gypsum surface with increasing solution temperature into account.
