Role of molecular oxygen in the dissolution of siderite and rhodochrosite

Duckworth, Owen W.; Martin, Scot T.

doi:10.1016/s0016-7037(03)00464-2

Cited by 101 publications

(107 citation statements)

References 62 publications

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“…La calcita es mucho más fácilmente alterable en condiciones ambientales que otros carbonatos como dolomita, ankerita o siderita (40,41). Por otra parte, las alteraciones de elementos planares continuos, como por ejemplo venas carbonatadas, pueden dañar a la pizarra en mucho mayor grado que la alteración de elementos carbonatados aislados, como por ejemplo granos detríticos.…”

Section: Discussionunclassified

“…Calcite is much more easily weathered in atmospheric conditions than other carbonates such as dolomite, ankerite or siderite (40,41). Furthermore, weathering of continuous planar elements, such as for example carbonate veins, can damage the slate much more than weathering of isolated carbonate elements, such as for example discrete carbonate grains.…”

Section: Discussionmentioning

confidence: 99%

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Evaluación de la fisibilidad y durabilidad de pizarras de techar mediante microscopía óptica y SEM

Gómez-Fernández¹,

Castano²,

Bauluz³

et al. 2009

Mater. construcc.

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RESUMENPara evaluar la fisibilidad y la durabilidad de pizarras de techar comerciales, muestras representativas de diez yacimientos del NO de España han sido estudiadas mediante microscopía óptica de luz transmitida y reflejada, microscopía electrónica de barrido y ensayos tecnológicos.Los sulfuros dominantes en las diferentes pizarras estudiadas son pirita o pirrotina, por lo que la alterabilidad de estas es muy variable. La especie carbonatada dominante es ankerita, lo que explica la baja reactividad de estas pizarras en medios ácidos. El espesor comercial mínimo varía en función de la microtextura de la roca, oscilando entre 3,5 y 5 mm.Se propone el uso de la metodología desarrollada en este trabajo, con objeto de eliminar la subjetividad de los inputs de entrada utilizados en las metodologías actuales de evaluación y modelización de yacimientos, lo que incidiría en la mejora de los rendimientos de las explotaciones y en la minimización de la producción de estériles.Palabras clave: Rocas ornamentales, Petrografía, Microscopía Electrónica de Barrido (MEB), Durabilidad, Modelización. SUMMARYThe fissility and durability of representative samples of commercial roofing slates from ten deposits in the NW of Spain have been evaluated using transmitted and reflectedlight optical microscopy, scanning electron microscopy, chemical testing and geomechanical procedures.The dominant sulphides in the different slate samples are pyrite and pyrrhotite, the weathering potential of which can be highly variable. The dominant carbonate mineral is ankerite, which explains the low reactivity of these slates in acidic media. The minimum commercial plate thickness varies between 3.5 and 5 mm, depending on the microtexture of the rock.The methodology used in this paper is proposed in order to eliminate the subjectivity of input data that are used in current methods of evaluation and modelling of slate deposits, thus producing an improvement in the profitability of mining operations and a reduction in waste materials. K Ke ey yw wo or rd ds s: : Ornamental stones, Petrography, Scanning Electron Microscopy (SEM), Durability, Modelization.

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Section: Discussionunclassified

Section: Discussionmentioning

confidence: 99%

Evaluación de la fisibilidad y durabilidad de pizarras de techar mediante microscopía óptica y SEM

Gómez-Fernández¹,

Castano²,

Bauluz³

et al. 2009

Mater. construcc.

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“…Note that siderite is initially undersaturated (SI ≈ -1.5) and thus unlikely to be present, except possibly as a detrital phase. For siderite, the kinetic rate reported by Duckworth and Martin (2004) is adopted. These investigators studied the dissolution of siderite under both oxic and anoxic conditions at 298 K, and fitted their measured data to a mechanistic kinetic equation similar to that employed in TOUGHREACT.…”

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confidence: 99%

“…Testemale et al (2009) confirmed that the dissolution rate constant of siderite at acid condition (pH < 4) can be expressed as: (Braun, 1991;Golubev et al, in press) and concluded that published kinetic rates for siderite dissolution are generally in good agreement. Duckworth and Martin (2004) also mentioned that the dissolution of siderite is retarded under oxic conditions, due to armoring by Fe (hydr)oxides. At the ZERT site, the proximity of the water table to ground surface and presence of secondary ferric oxy-hydroxides suggest oxic to suboxic conditions may prevail, at least during rainfall events.…”

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Groundwater Chemistry Changes as a Result of CO2 Injection at the ZERT Field Site in Bozeman, Montana

Apps¹,

Birkhölzer²,

Spycher³

et al. 2009

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Identification and quantification of redox and pH buffering processes in a heterogeneous, low carbonate aquifer during managed aquifer recharge

Seibert

Atteia

Salmon

et al. 2016

Water Resources Research

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Managed aquifer recharge of aerobic water into deep aquifers often induces the oxidation of pyrite, which can lead to groundwater acidification and metal mobilization. As circumneutral pH is often maintained by the dissolution of sedimentary calcite or high injectant alkalinity little attention is generally paid to potential alternative pH buffering processes. In contrast, this study analyzed water quality evolution from a 2 year long groundwater replenishment trial in an anaerobic, mostly carbonate free aquifer. While injection of aerobic, very low salinity water triggered pyrite oxidation, the comprehensive field data showed that in many aquifer zones pH was buffered without substantial release of inorganic carbon. A numerical analysis was performed to test and evaluate different conceptual models and suggested that either proton buffering or the dissolution of aluminosilicates, or a combination thereof, can explain the observed, rapid buffering at locations where carbonates were absent. In contrast to many previous managed aquifer recharge [MAR) studies, the oxidation of sedimentary pyrite by nitrate was found to be of minor importance or negligible. The study also highlights that the depositional history of the aquifer, and the associated differences in mineralogy and geochemistry, need to be considered when estimating groundwater quality evolution during the injection of various water types for aquifer replenishment or other management purposes. ] describe sequential buffering during ongoing pyrite oxidation in a carbonate-bearing mine waste. After the initial consumption of primary and secondary carbonates (calcite and siderite), they observed the dissolution of previously precipitated gibbsite at pH 4.9-5.2, and subsequent ferrihydrite dissolution at pH < 4.5. Salmon and Malmstr€ om [2004] found that the pH of 4.9 in the groundwater of a carbonate-free mine waste deposit could largely be explained by a balance of acid generation by pyrite oxidation and acid consumption by chlorite and ferrihydrite dissolution.

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Role of molecular oxygen in the dissolution of siderite and rhodochrosite

Cited by 101 publications

References 62 publications

Evaluación de la fisibilidad y durabilidad de pizarras de techar mediante microscopía óptica y SEM

Evaluación de la fisibilidad y durabilidad de pizarras de techar mediante microscopía óptica y SEM

Groundwater Chemistry Changes as a Result of CO2 Injection at the ZERT Field Site in Bozeman, Montana

Identification and quantification of redox and pH buffering processes in a heterogeneous, low carbonate aquifer during managed aquifer recharge

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