Salinization of water bodies represents a significant risk in water systems. The salinization of ... more Salinization of water bodies represents a significant risk in water systems. The salinization of waters in a small irrigated hydrological basin is studied herein through an integrated hydrogeochemical study including multivariate statistical analyses and geochemical modeling. The study zone has two well differentiated geologic materials: (i) Quaternary sediments of low salinity and high permeability and (ii) Tertiary sediments of high salinity and very low permeability. In this work, soil samples were collected and leaching experiments conducted on them in the laboratory. In addition, water samples were collected from precipitation, irrigation, groundwater, spring and surface waters. The waters show an increase in salinity from precipitation and irrigation water to ground- and, finally, surface water. The enrichment in salinity is related to the dissolution of soluble mineral present mainly in the Tertiary materials. Cation exchange, precipitation of calcite and, probably, incongrue...
A dissolution rate law for galena in acidic environment was derived from the steady-state dissolu... more A dissolution rate law for galena in acidic environment was derived from the steady-state dissolution rates using flow-through experiments. The influence of temperature, dissolved oxygen concentration and pH between 1 and 3 was assessed. This rate law can be used for predicting galena dissolution behavior in a wide range of conditions analogous to Acid Rock Drainage.
... La muestra se extrae directamente del tubo de vacío por un tubo drenante de acero inoxidable,... more ... La muestra se extrae directamente del tubo de vacío por un tubo drenante de acero inoxidable, extrayendose entre 4 y 8 ml de muestra. 2 ml son destinados a la medición de pH-Eh con un pHmetro Crison y Ehmetro Hanna 9025 con electrodos de membrana de vidrio y ...
Arsenopyrite oxidative dissolution is a process that supplies arsenic in waters. The effects that... more Arsenopyrite oxidative dissolution is a process that supplies arsenic in waters. The effects that environmental factors (e.g., variation of pH, concentration of iron and sulfate, and surface reactivity) exert on the arsenopyrite (AsFeS) decomposition rate are studied by means of flow-through experiments. Preliminary results suggest that the arsenopyrite decomposition rate is not affected by pH in very acidic conditions. Arsenic in the output solutions is present as As(III) and As(V) and the respective amount depends on the O 2 availability during the arsenopyrite oxidation.
... Area, Earth Sciences Department, University of Zaragoza, c/Pedro Cerbuna 12, 50009-Zaragoza (... more ... Area, Earth Sciences Department, University of Zaragoza, c/Pedro Cerbuna 12, 50009-Zaragoza (Spain) (*correspondence: patricia.acero@unizar.es) ... C. MARK MOORE 1, POLLY HILL 1, CLAIRE POWELL 2, CLAIRE MAHAFFEY 3, PETER J. STATHAM 1, DUNCAN PURDIE 1 ...
The composition of a garnierite (Mg-Ni silicate) from the Loma de Hierro Ni-laterite deposit (Ven... more The composition of a garnierite (Mg-Ni silicate) from the Loma de Hierro Ni-laterite deposit (Venezuela) has been determined by means of XRD, TEM and EM (electron microprobe) analyses. This garnierite was collected from a vein in the parent rock of the laterite (serpentinized peridotite).
Keywords: Acid mine drainage Hardpan Metal mobility Micro-X-ray fluorescence Micro-X-ray diffract... more Keywords: Acid mine drainage Hardpan Metal mobility Micro-X-ray fluorescence Micro-X-ray diffraction Synchrotron radiation Pilot-scale field experiments were conducted to test a strategy for the treatment of acid mine drainage by addition of an alkaline cover of coal combustion fly ash on two sulfide mine tailings impoundments (Iberian Pyrite Belt, SW Spain). During the pilot-scale treatment, calcium-rich alkaline solutions from fly ash interacted with metal-rich acidic solutions from the mine tailings, leading to the massive precipitation of newly-formed phases mainly in the fly ash close to the interface between both materials. Over time, the interaction between fly ash and pyrite sludge promoted the formation of a chemically cemented zone or hardpan, which was analyzed at high spatial resolution by micro-X-ray diffraction (μ-XRD) and micro-X-ray fluorescence (μ-XRF) based on synchrotron radiation. These micro-characterization techniques extensively identified poorlycrystalline Fe oxyhydroxysulfates, jarosite and gypsum as newly-formed phases in the hardpan, and gypsum in the fly ash. As deduced from Principal Component Analysis of the fluorescence intensity data, these phases seem to exert a significant mineralogical control on element mobility; in particular, jarosite showed high affinity for As, whereas poorly-crystalline Fe-rich assemblages selectively concentrated Mn, Ni and Pb. Sequential extractions indicated that the application of a fly ash cover significantly reduced the bioavailability of most of the elements by modification of their chemical speciation into less mobile forms under typical oxidizing conditions. As an additional advantage, the development of the hardpan hindered the penetration of oxidizing agents to sulfide mine tailings. This effect significantly reduced the sulfide oxidation rates, therefore attenuating the release of potentially pollutant elements to the environment.
Salinization of water bodies represents a significant risk in water systems. The salinization of ... more Salinization of water bodies represents a significant risk in water systems. The salinization of waters in a small irrigated hydrological basin is studied herein through an integrated hydrogeochemical study including multivariate statistical analyses and geochemical modeling. The study zone has two well differentiated geologic materials: (i) Quaternary sediments of low salinity and high permeability and (ii) Tertiary sediments of high salinity and very low permeability. In this work, soil samples were collected and leaching experiments conducted on them in the laboratory. In addition, water samples were collected from precipitation, irrigation, groundwater, spring and surface waters. The waters show an increase in salinity from precipitation and irrigation water to ground- and, finally, surface water. The enrichment in salinity is related to the dissolution of soluble mineral present mainly in the Tertiary materials. Cation exchange, precipitation of calcite and, probably, incongrue...
A dissolution rate law for galena in acidic environment was derived from the steady-state dissolu... more A dissolution rate law for galena in acidic environment was derived from the steady-state dissolution rates using flow-through experiments. The influence of temperature, dissolved oxygen concentration and pH between 1 and 3 was assessed. This rate law can be used for predicting galena dissolution behavior in a wide range of conditions analogous to Acid Rock Drainage.
... La muestra se extrae directamente del tubo de vacío por un tubo drenante de acero inoxidable,... more ... La muestra se extrae directamente del tubo de vacío por un tubo drenante de acero inoxidable, extrayendose entre 4 y 8 ml de muestra. 2 ml son destinados a la medición de pH-Eh con un pHmetro Crison y Ehmetro Hanna 9025 con electrodos de membrana de vidrio y ...
Arsenopyrite oxidative dissolution is a process that supplies arsenic in waters. The effects that... more Arsenopyrite oxidative dissolution is a process that supplies arsenic in waters. The effects that environmental factors (e.g., variation of pH, concentration of iron and sulfate, and surface reactivity) exert on the arsenopyrite (AsFeS) decomposition rate are studied by means of flow-through experiments. Preliminary results suggest that the arsenopyrite decomposition rate is not affected by pH in very acidic conditions. Arsenic in the output solutions is present as As(III) and As(V) and the respective amount depends on the O 2 availability during the arsenopyrite oxidation.
... Area, Earth Sciences Department, University of Zaragoza, c/Pedro Cerbuna 12, 50009-Zaragoza (... more ... Area, Earth Sciences Department, University of Zaragoza, c/Pedro Cerbuna 12, 50009-Zaragoza (Spain) (*correspondence: patricia.acero@unizar.es) ... C. MARK MOORE 1, POLLY HILL 1, CLAIRE POWELL 2, CLAIRE MAHAFFEY 3, PETER J. STATHAM 1, DUNCAN PURDIE 1 ...
The composition of a garnierite (Mg-Ni silicate) from the Loma de Hierro Ni-laterite deposit (Ven... more The composition of a garnierite (Mg-Ni silicate) from the Loma de Hierro Ni-laterite deposit (Venezuela) has been determined by means of XRD, TEM and EM (electron microprobe) analyses. This garnierite was collected from a vein in the parent rock of the laterite (serpentinized peridotite).
Keywords: Acid mine drainage Hardpan Metal mobility Micro-X-ray fluorescence Micro-X-ray diffract... more Keywords: Acid mine drainage Hardpan Metal mobility Micro-X-ray fluorescence Micro-X-ray diffraction Synchrotron radiation Pilot-scale field experiments were conducted to test a strategy for the treatment of acid mine drainage by addition of an alkaline cover of coal combustion fly ash on two sulfide mine tailings impoundments (Iberian Pyrite Belt, SW Spain). During the pilot-scale treatment, calcium-rich alkaline solutions from fly ash interacted with metal-rich acidic solutions from the mine tailings, leading to the massive precipitation of newly-formed phases mainly in the fly ash close to the interface between both materials. Over time, the interaction between fly ash and pyrite sludge promoted the formation of a chemically cemented zone or hardpan, which was analyzed at high spatial resolution by micro-X-ray diffraction (μ-XRD) and micro-X-ray fluorescence (μ-XRF) based on synchrotron radiation. These micro-characterization techniques extensively identified poorlycrystalline Fe oxyhydroxysulfates, jarosite and gypsum as newly-formed phases in the hardpan, and gypsum in the fly ash. As deduced from Principal Component Analysis of the fluorescence intensity data, these phases seem to exert a significant mineralogical control on element mobility; in particular, jarosite showed high affinity for As, whereas poorly-crystalline Fe-rich assemblages selectively concentrated Mn, Ni and Pb. Sequential extractions indicated that the application of a fly ash cover significantly reduced the bioavailability of most of the elements by modification of their chemical speciation into less mobile forms under typical oxidizing conditions. As an additional advantage, the development of the hardpan hindered the penetration of oxidizing agents to sulfide mine tailings. This effect significantly reduced the sulfide oxidation rates, therefore attenuating the release of potentially pollutant elements to the environment.
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