Hydration of anhydrite of gypsum (CaSO4.II) in a ball mill

Sievert, T.; Wolter, Albrecht; Singh, N. B.

doi:10.1016/j.cemconres.2004.02.010

Cited by 68 publications

(46 citation statements)

References 3 publications

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“…Many researchers have studied the transformation of gypsum and anhydrite and found that gypsum is more prevalent at lower temperatures, while anhydrite is the stable form at higher temperatures (e.g., Ostroff 1964;Innorta et al 1980;Kushnir 1982;Zhang et al 1996;Sievert et al 2005). Early experiments showed that conversion occurs as gypsum changes to bassanite and then anhydrite (Conley and Bundy 1958;Ostroff 1964).…”

Section: Formation and Stability Of Ca-sulfatesmentioning

confidence: 97%

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Spectral properties of Ca-sulfates: Gypsum, bassanite, and anhydrite

Bishop

Lane

Dyar

et al. 2014

American Mineralogist

137

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This study of the spectral properties of Ca-sulfates was initiated to support remote detection of these minerals on Mars. Gypsum, bassanite, and anhydrite are the currently known forms of Ca-sulfates. They are typically found in sedimentary evaporites on Earth, but can also form via reaction of acidic fluids associated with volcanic activity. Reflectance, emission, transmittance, and Raman spectra are discussed here for various sample forms. Gypsum and bassanite spectra exhibit characteristic and distinct triplet bands near 1.4-1.5 μm, a strong band near 1.93-1.94 μm, and multiple features near 2.1-2.3 μm attributed to H 2 O. Anhydrite, bassanite, and gypsum all have SO 4 combination and overtone features from 4.2-5 μm that are present in reflectance spectra. The mid-IR region spectra exhibit strong SO 4 ν 3 and ν 4 vibrational bands near 1150-1200 and 600-680 cm -1 (~8.5 and 16 μm), respectively. Additional weaker features are observed near 1005-1015 cm -1 (~10 μm) for ν 1 and near 470-510 cm -1 (~20 μm) for ν 2 . The mid-IR H 2 O bending vibration occurs near 1623-1630 cm -1 (~6.2 μm). The visible/near-infrared region spectra are brighter for the finer-grained samples. In reflectance and emission spectra of the mid-IR region the ν 4 bands begin to invert for the finer-grained samples, and the ν 1 vibration occurs as a band instead of a peak and has the strongest intensity for the finer-grained samples. The ν 2 vibration is a sharp band for anhydrite and a broad peak for gypsum. The band center of the ν 1 vibration follows a trend of decreasing frequency (increasing wavelength) with increasing hydration of the sample in the transmittance, Raman, and reflectance spectra. Anhydrite forms at elevated temperatures compared to gypsum, and at lower temperature, salt concentration, and pH than bassanite. The relative humidity controls whether bassanite or gypsum is stable. Thus, distinguishing among gypsum, bassanite, and anhydrite via remote sensing can provide constraints on the geochemical environment.

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Section: Formation and Stability Of Ca-sulfatesmentioning

confidence: 97%

“…Particulate anhydrite will slowly react to form gypsum at low temperatures when water is added, making it a useful component of cement (e.g., Sievert et al 2005). Gypsum and anhydrite are often located together when large marine evaporite deposits were formed under variable temperatures (Appleyard 1983;Haynes et al 1989).…”

Section: Introductionmentioning

confidence: 99%

Spectral properties of Ca-sulfates: Gypsum, bassanite, and anhydrite

Bishop

Lane

Dyar

et al. 2014

American Mineralogist

137

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show abstract

“…Gypsum deposition generally prevails over anhydrite for temperatures below 40 1C (e.g. Sievert et al, 2005). YSD formed by unknown processes and covered portions of SLM, LB, and the gypsum.…”

Section: Sequence Of Eventsmentioning

confidence: 99%

Gypsum, opal, and fluvial channels within a trough of Noctis Labyrinthus, Mars: Implications for aqueous activity during the Late Hesperian to Amazonian

Weitz

Bishop

Grant

2013

Planetary and Space Science

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“…Estos procesos son los de mayor aceptación para el semihidrato; no obstante, Sievert et al profundizan en el mecanismo de hidratación de la anhidrita a yeso mediante experimentos en un molino de bolas [Sievert et al, 2005]. Los autores señalan que, al igual que para el semihidrato, la secuencia inicia cuando la fase deshidratada entra en contacto con el agua de amasado, en la que parte de ella se disuelve, saturando la solución con respecto a iones de calcio (Ca 2+ ) y sulfato (SO 4 2-); posteriormente, estos iones hidratados se adsorben rápidamente en la superficie de las partículas de anhidrita, generando una nueva capa que aumenta su espesor paulatinamente, y por lo tanto, aumentando la superficie de las partículas.…”

Section: Requerimiento (Importancia) (E) / (I)unclassified

“…2.6. Mecanismo de hidratación de la anhidrita [Sievert et al, 2005]. Imagen traducida y redibujada por el doctorando.…”

Section: Requerimiento (Importancia) (E) / (I)unclassified

Comportamiento térmico y mecánico del yeso con adiciones de aerogel de sílice granulado

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Hydration of anhydrite of gypsum (CaSO4.II) in a ball mill

Cited by 68 publications

References 3 publications

Spectral properties of Ca-sulfates: Gypsum, bassanite, and anhydrite

Spectral properties of Ca-sulfates: Gypsum, bassanite, and anhydrite

Gypsum, opal, and fluvial channels within a trough of Noctis Labyrinthus, Mars: Implications for aqueous activity during the Late Hesperian to Amazonian

Comportamiento térmico y mecánico del yeso con adiciones de aerogel de sílice granulado

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