SOLUBILITY OF MAGNETITE IN HIGH-TEMPERATURE WATER AND AN APPROACH TO GENERALIZED SOLUBILITY COMPUTATIONS

Magnetite solubility in pure water was measured at 423 K in a fully te flon-covered autoclave system. A fairly good agreement was found to ex ist between the experimental data and calculation results obtained fro m the thermodynamical model, based on the assumption of Fe3O4 dissolut ion and Fe2O3 deposition reactions. A generalized thermodynamical appr oach to the solubility computations under complex conditions on the ba sis of minimization of the total system Gibbs free energy was proposed . The forms of the chemical equilibria were obtained for various syste ms initially defined and successfully justified by the subsequent comp utations. A [Fe3+](T)-[Fe2+](T) phase diagram was introduced as a tool for systematic understanding of the magnetite dissolution phenomena i n pure water and under oxidizing and reducing conditions.