Solubility of CO 2 in the molten NA 2CO 3—K 2CO 3 (42 mol %) eutectic mixture at 800 °C

Abstract

The solubility of CO 2 in the molten Na 2CO 3—K 2CO 3 eutectic mixture at 800 °C has been measured using a manometric method. The corresponding Henry's constant amounts to 1.83 10 −1 mol 1 −1 atm −1 which is a rather high value in comparison with other values reported in the literature for CO 2 in carbonate melts at lower temperature. A diffusion coefficient of 4.5 × 10 −5cm 2s −1 has been evaluated from the experimental data for CO 2 in the investigated melt. The CO 2 CO system is electroactive but the peak current for the reduction of CO 2 appears to be low if the solubility is taken into account. An explanation is proposed which involves the production of C 2O 5 2− ions by reaction between CO 2 and the melt.