An accurate model for the solubilities of quartz in aqueous NaCl and/or CO2 solutions at temperatures up to 1273 K and pressures up to 20,000 bar

Abstract

A simple and general relation between the solubility of quartz and the density of solution is derived rigorously. Based on this relation and the pressure-volume-temperature-composition model of Mao et al. (2010), an accurate density-based model is developed for the solubility of quartz in aqueous NaCl and/or CO2 solution up to 1273 K and 20,000 bar. The model parameters are regressed with carefully assessed experimental data. Compared to a large number of experimental data, the average absolute deviations of calculated quartz solubilities in water, aqueous NaCl solution and aqueous CO2 solution are 5.50%, 5.24% and 7.55%, respectively, which are within experimental uncertainties, and are much better than the most competitive models in literature. Particularly, this model can predict the experimental solubility of quartz in aqueous NaCl and CO2 solution without using any additional parameter. This model can be incorporated in software for accurate geochemical modeling. The strategy of this model should be promising for the solubilities of other minerals in water or multicomponent aqueous solutions.