EXPERIMENTAL-STUDY OF HYDROGEN ISOTOPE KINETIC FRACTIONATION BETWEEN ILVAITE AND WATER - THE KINETICS OF D-H EXCHANGE IN ILVAITE-H2O

Hydrogen isotope kinetic fractionation in the ilvaite and water system has been studied experimentally at 350-650-degrees-C. The result of study shows that the exchange mechanism of hydrogen isotope between ilvaite and water is dominated by hydrogen diffusion. The activation energy for hydrogen diffusion in ilvaite is 118.4 kJ/mol for cylinder model and 115.5 kJ/mol for plate model, respectively. The activation energy for hydrogen isotope exchange in ilvaite is 122.6 kJ/mol. The closure temperature for the cessation of hydrogen isotope exchange between ilvaite and water is much lower than its formation temperature. So, after ilvaite crystallizes, the hydrogen isotope exchange between ilvaite and late hydrothermal solution will continue to take place.