Thermal reduction of molybdite and hematite in water and hydrogen peroxide-bearing solutions: Insights on redox conditions in Hydrothermal Diamond Anvil Cell (HDAC) experiments

摘要: Abstract The oxygen fugacity in Hydrothermal Diamond Anvil Cell (HDAC) experiments was determined by means of direct observation the thermal reduction molybdite or hematite water and water–H 2 O solutions. HDAC were conducted with without rhenium gasket order to evaluate effect on contained sample. In where pure no Re used, i.e., when sample charge is loaded into a laser-drilled recess lower anvil, Log(fO ) shown be − 19.55 ± 0.13 over wide range temperature pressure conditions (335–500 °C, 15.0–136.3 MPa — using EOS Wagner Pruss, 2002), HM + 8 HM − 0.5, at limit temperatures. contrast, used contain sample, slightly more reducing (− 20.60 ± 0.04), e.g., equals HM + 6 350 °C, but significantly higher than that predicted given Re–ReO buffer. Experiments hydrogen peroxide showed non-linear increase increasing molarity H from 0.10 0.25 M. Results indicate dominated runs imposed fluid medium, may water-dominated media experiments.