Solubility of quartz in supercritical water from 375 °C to 600 °C and 200–270 bar

The solubility of quartz in deionized water has been determined experimentally from 375 °C to 600 °C and 200–270 bar. The experiments were performed using a unique flow-through reactor capable of reaching supercritical conditions for pure water. The results cover the approximate range of temperature and pressure expected to be found in deep geothermal systems where supercritical conditions could be expected. Quartz solubility has not been previously well-defined in this region. The new experimental data are used to refine the empirical parameters in the original Fournier and Potter [1] equation for quartz solubility: logm=A+B(logV)+C(logV)² where m is the silica concentration in mol∙kg⁻¹ and V is the specific volume of pure water in cm³∙g^₋1. These parameters are applicable to the range of temperature and pressure of the original equation: A = 3.775 + 0.0001215 T – 5500 T⁻¹ + 1.779 × 10⁶T⁻² – 2.499 × 10⁸T⁻³ B = – 0.001406 T – 819.1 T^-l C = 3.923 × 10⁻⁴T T is temperature in K.