Solubility of sodium-jarosite and solution speciation in the system fe(iii)-na-h2so4-h2o at 70 degrees c

JOURNAL OF GEOCHEMICAL EXPLORATION;
J. Geochem. Explor.

dc.creatorVargas-Valero, Tomás
dc.creatorGodoy-Ríos, Inés
dc.creatorPaipa-Gómez, Carolina
dc.creatorCasas-De Prada, Jesús
dc.date2017-04-27T18:53:05Z
dc.date2022-07-07T02:25:41Z
dc.date2017-04-27T18:53:05Z
dc.date2022-07-07T02:25:41Z
dc.date2007
dc.date.accessioned2023-08-23T00:01:33Z
dc.date.available2023-08-23T00:01:33Z
dc.identifierD00I1050
dc.identifierD00I1050
dc.identifierWOS:000243870700003
dc.identifier0375-6742
dc.identifierhttps://hdl.handle.net/10533/197831
dc.identifier.urihttps://repositorioslatinoamericanos.uchile.cl/handle/2250/8353501
dc.descriptionThe aim of this work was to study the formation and chemical equilibrium of sodium-jarosite in synthetic Fe(III)-Na-HSO4-H2O solutions at 70 degrees C. Solutions were prepared adding sodium as NaOH and ferric iron as FeH(SO4)(2), Sulphuric acid solutions of different acidities and containing different initial concentrations of ferric iron were prepared, introduced in sealed flasks and left for 45 days in a rotating oven until equilibrium was reached. Final equilibrium solutions, after separation of formed precipitates by filtration, were analyzed by free acidity, total acidity, pH, Eh, and concentration of sodium, iron and sulfate. Formed precipitates were characterized by chemical analysis, DRX, Raman and FT-IR spectroscopy. Equilibrium solution data was analyzed using a thermodynamic model which described ionic interactions in the system. Experimental studies on the formation of sodiurn-jarosite at 70 degrees C showed that at pH 1.72 sodium-jarosite is obtained forming mixtures with goethite. A pure crystalline natro-jarosite phase is obtained only in solutions with pH <= 1.42. Chemical analysis of this crystalline sodium-jarosite phase, however, indicates that is formed by a series of hydronium:natro-jarosites with iron deficiency and excess water, in which hydronium partially replaces sodium in the structure. A good fitting of the experimental data for sodium-jarosite solubility was obtained using a thermodynamic model which described ionic interactions in terms of Davis model for activity coefficients. The standard equilibrium constant obtained for sodium-jarosite formation at 70 degrees C was calculated assuming for the solid the ideal stoichiometry Na[Fe-3(SO4)(2)(OH)(6)], giving Log K-0 = 16.5 +/- 0.3. Speciation calculations conducted with this model showed that dissolved iron is highly associated being iron-sulphate-complexes FeH(SO4)(2(aq)) and Fe(SO4)(2)(-) the main species present. (c) 2006 Elsevier B.V All rights reserved.
dc.description16
dc.descriptionFONDEF
dc.description3
dc.descriptionFONDEF
dc.description92
dc.languageENG
dc.publisherELSEVIER SCIENCE BV
dc.relationinstname: Conicyt
dc.relationreponame: Repositorio Digital RI2.0
dc.relationinstname: Conicyt
dc.relationreponame: Repositorio Digital RI2.0
dc.relationinfo:eu-repo/grantAgreement/Fondef/D00I1050
dc.relationinfo:eu-repo/semantics/dataset/hdl.handle.net/10533/93477
dc.relationhttps://doi.org/10.1016/j.gexplo.2006.08.009
dc.rightsinfo:eu-repo/semantics/openAccess
dc.titleSolubility of sodium-jarosite and solution speciation in the system fe(iii)-na-h2so4-h2o at 70 degrees c
dc.titleJOURNAL OF GEOCHEMICAL EXPLORATION
dc.titleJ. Geochem. Explor.
dc.typeArticulo
dc.typeinfo:eu-repo/semantics/article
dc.typeinfo:eu-repo/semantics/publishedVersion
dc.coverageAMSTERDAM


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