Barite precipitation following celestite dissolution in a porous medium: A SEM/BSE and μ-XRD/XRF study

Barite precipitation following celestite dissolution in a porous medium: A SEM/BSE and μ-XRD/XRF study

•SrSO4 replacement by BaSO4 was studied at the pore scale in a porous medium.•Spatially resolved μ-XRD data showed formation of two distinct BaSO4 generations.•BaSO4 was found to grow as nanocrystals in the pore and as an epitaxial rim on SrSO4.•The results could be partially explained using classic...

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Veröffentlicht in:Geochimica et cosmochimica acta 2016-06, Vol.182, p.131-144
Hauptverfasser: Poonoosamy, J., Curti, E., Kosakowski, G., Grolimund, D., Van Loon, L.R., Mäder, U.
Format: Artikel
Sprache:eng
Schlagworte:
Barite
Celestite
Dissolution
Grains
Nucleation
Porosity
Sand
Scanning electron microscopy
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Zusammenfassung:•SrSO4 replacement by BaSO4 was studied at the pore scale in a porous medium.•Spatially resolved μ-XRD data showed formation of two distinct BaSO4 generations.•BaSO4 was found to grow as nanocrystals in the pore and as an epitaxial rim on SrSO4.•The results could be partially explained using classical nucleation theory. A reaction cell experiment was designed to examine mineral dissolution/precipitation processes both at the macroscopic and pore scale. A rectangular flow cell was filled with a reactive porous layer lying between two porous layers composed of quartz sand (SiO2). The reactive layer consisted of celestite (or celestine, SrSO4) with a bimodal grain size distribution (
ISSN:0016-7037
1872-9533
DOI:10.1016/j.gca.2016.03.011