Kinetics and rate-limiting mechanisms of dolomite dissolution at various CO2 partial pressures

Techniques of rotating-disk and catalyst were used in investigating the kinetics of dolomite dissolution in flowing CO2-H2O system. Experiments run in the solutions equilibrated with various CO2 partial pressures (P-CO2) from 30 to 100000 Pa. It shows that dissolution rates of dolomite are related with rotating speeds at conditions far from equilibrium. This was explained by modified diffusion boundary layer (DBL) model. In addition, the dissolution rates increase after addition of carbonic anhydrase (CA) to solutions, where the CA catalyzes CO2 conversion. However, great differences occur among various CO2 partial pressures. The experimental observations give a conclusion that the modified DBL model enables one to predict dissolution rates and their behaviour at various P-CO2 with satisfactory precision at least far from equilibrium.