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

作　　者：曾贻善 艾瑞英 王凤珍 

机构地区：[1]Department of Geology, Peking University, Beijing 100871, PRC

出　　处：《Science China Chemistry》1993年第4期472-481,共10页中国科学（化学英文版）

基　　金：This research was supported by the National Natural Science Foundation of China (4870203).

摘　　要：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. △G_5~0,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.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.

关 键 词：magnetite+hematite BUFFER ASSEMBLAGE SOLUBILITY HCI hydrothermal solution Fe-speciation free energy of formation. 

分 类 号：O6[理学—化学]