Papers by Keyword: PHREEQC

Abstract: This paper looked back on the current situation about simulation using PHREEQC of heavy metal transport in soil and the current situation of coupling with other value simulation software. On such a base, the feasibility, advantages and problems of heavy metal reactive solute transport in soil using PHREEQC were discussed.

Abstract: In geological disposal of radioactive wastes, the study of Plutonium migration is very important for the safety evaluation of the repository. The forms of chemical components of Plutonium presence in aqueous solution that directly affect its migration behavior provide a basis for analog computation of the element. This paper uses PHREEQC, the geochemical model, for analog computation of forms of Plutonium presence in two types of groundwater, and analyzes the morphologies of the main elements and the influencing factors. The results show that the morphology of Plutonium is mainly controlled by the characteristics of the chemical composition of groundwater, while the PH value also has a great impact on the forms of Plutonium presence.

Abstract: In geological disposal of radioactive wastes, the study of Americium migration is very important for the safety evaluation of the repository. The forms of chemical components of Americium presence in aqueous solution that directly affect its migration behavior provide a basis for analog computation of the element. This paper uses PHREEQC, the geochemical model, for analog computation of forms of Americium presence in two types of groundwater, and analyzes the morphologies of the main elements and the influencing factors. The results show that the morphology of Americium is mainly controlled by the characteristics of the chemical composition of groundwater, while the PH value also has a great impact on the forms of Americium presence.

Abstract: In geological disposal of radioactive wastes, the study of uranium migration is very important for the safety evaluation of the repository. The forms of chemical components of uranium presence in aqueous solution that directly affect its migration behavior provide a basis for analog computation of the element. This paper uses PHREEQC, the geochemical model, for analog computation of forms of uranium presence in two types of groundwater, and analyzes the morphologies of the main elements and the influencing factors. The results show that the morphology of uranium is mainly controlled by the characteristics of the chemical composition of groundwater, while the PH value also has a great impact on the forms of uranium presence.

Abstract: Geochemical modeling program PHREEQC was used to simulate generic bioleaching processes. Carbonate minerals (e.g., calcite) dissolve in acid solution, increasing the solution pH and Ca concentration while the concentration of CO2 may be controlled by the equilibrium with the atmospheric CO2. Non-oxidative dissolution of Fe-monosulphides was demonstrated to release H2S and increase the pH. In the absence of ferric iron precipitation (goethite), the oxidation of pyrite decreased the solution pH from 2 to ~1.4, while the oxidation of Fe-monosulphide and chalcopyrite increased the solution pH to ~3.2-3.4. Assuming equilibrium precipitation of goethite, oxidative leaching decreased the solution pH for all three minerals from pH ~2 to ~0.9-1.2. Adjustment of the solution pH to 1.8 or 2.0 with KOH with concurrent equilibrium precipitation of K-jarosite resulted in low dissolved iron concentrations.