Solubility Study of the MH Buffer Assemblage in HCl Solutions at 300℃ and 500 bar

【摘要】 <正> Using a gold cell hydrothermal apparatus the solubility of the MH （magnetite + hematite）buffer assemblage in HCl aqueous solutions was determined at 300℃ and 500 bar. The activity of ions in hydrothermal solutions was estimated, and the experiment data were treated by ridge regression and iteration to fit to all possible Fe speciation schemes. The result showed that the dominant Fe species in solutions was FeOH⁺ under the run conditions. The equilibrium constant for the dissolution reaction was obtained, K=57.161. △G₅⁰,FeOH⁺ value of -260.3 kJ/mol at 300℃ and 500 bar was calculated. Fe basically exists as Fe-OH species in hydrothermal solution under geologically reasonable conditions of pH and chloride concentration.更多还原

【Abstract】 Using a gold cell hydrothermal apparatus the solubility of the MH （magnetite + hematite）buffer assemblage in HCl aqueous solutions was determined at 300℃ and 500 bar. The activity of ions in hydrothermal solutions was estimated, and the experiment data were treated by ridge regression and iteration to fit to all possible Fe speciation schemes. The result showed that the dominant Fe species in solutions was FeOH⁺ under the run conditions. The equilibrium constant for the dissolution reaction was obtained, K=57.161. △G₅⁰,FeOH⁺ value of -260.3 kJ/mol at 300℃ and 500 bar was calculated. Fe basically exists as Fe-OH species in hydrothermal solution under geologically reasonable conditions of pH and chloride concentration.更多还原