Interactions in the system [basalt-SO2-O2 ± S2]: A thermodynamic model

A thermodynamic model for gas-rock interactions in the system [basalt-SO2-O2±S2] is suggested. Calculations are performed for a wide range of temperatures (100–850°C) and pressures (1–1000 bars). The high-temperature part of this model was verified by experimental research, which was carried out at 850, 650 and 450°C. The modeling prediction of interactions in the system [(alumino)silicates SO2-O2±S2] at relatively low temperatures (100–300°C) gives steady mineral associations that are typical for natural secondary quartzites: quartz-pyrite-hematite-Al-silicates-metal sulfates (Ca, Mg, Na, K, Al, and Fe). The formation of sulfates stabilizes the level of SO2 concentration in the gas phase; this level falls with a temperature decrease.