The solubility of CaCO3 (calcite), SiCO3 (strontianite), and BaCO3 (witherite) has been determined in NaCl solutions from 0.1 to 6 m at 25°C. Activity coefficients estimated from Pitzer's equations with higher order interaction terms (θ and Ψ) were used to extrapolate the results to infinite dilution. Thermodynamic values of pKsp = 8.46 ± 0.03,9.13 ± 0.03 and 8.56 ± 0.04 were found, respectively, for CaCO3, SrCO3 and BaCO3 at 25°C. These results are in reasonable agreement with literature data. Since Pitzer parameters for the interactions of CO32- with Ca2+, Sr2+ and Ba2+ were not used, our results indicate that they are not necessary at low values of Pco2.
ASJC Scopus subject areas
- Geochemistry and Petrology