RESUMO
The experiments on the exchange reaction rate of the oxygen isotopes in the mineral-water system with initial conditions of 100 °C and 240 MPa, 100 °C and 924 MPa, 118 °C and 170 MPa are taken. The oxygen isotope 18O exchange reactions between aqueous C16O32- and H218O are mainly traced by measuring the Raman peak intensity of oxygen-containing elements (CO32-) in sodium carbonate solution. The inconsistent trends between the molar fraction and the concentration of C18O216O2- indicate oxygen isotope exchange between sodium carbonate and heavy water accompanied by dissolution and recrystallization between supersaturated sodium carbonate solution and solid sodium carbonate. In the heterogeneous experimental systems the order of oxygen isotope exchange reactions are more than 1 and the dynamics of oxygen isotope exchange conform to JMAK kinetics model with the nucleation and growth processes of sodium carbonate crystal.
