THERMODYNAMIC MODELLING OF THE CINNABAR AND METACINNABAR COEXISTENCE
Keywords:
cinnabar, metacinnabar, thermodynamic modelling.Abstract
Polymorphic transitions between cinnabar and metacinnabar have been studied using numerical physicochemical modelling of mineralization in the GEM-Selektor software package (GEMS3). System components were selected with the simulation of medium- and low-temperature hydrothermal conditions; in the reaction, solutions were taken with salinity of 8, 16, 20 and 40 wt. % NaCl eq. The buffer equilibrium of oxidizing–reducing conditions was maintained with H2S–H2SO4. The pressure was changed from 100 to 1 000 bar. The temperature interval of estimation of mineral equilibrium states was 225–525 °С. Increasing pressure promotes the metacinnabar formation. The stability field of existence of metacinnabar expands at higher values of pressure, and the change in salinity of solutions does not affect the conditions of polymorphic transformation.
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