Chemomechanical influences during replacement of limestones by siderite

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dc.contributor.authorWeber, Jen_AU
dc.contributor.authorStarchenko, Ven_AU
dc.contributor.authorZhang, Ren_AU
dc.contributor.authorIlavsky, Jen_AU
dc.contributor.authorDebeer-Schmidt, Len_AU
dc.contributor.authorMata, JPen_AU
dc.contributor.authorLittrell, Ken_AU
dc.contributor.authorHe, Len_AU
dc.contributor.authorChen, WRen_AU
dc.contributor.authorAllard, LFen_AU
dc.contributor.authorStack, AGen_AU
dc.contributor.authorAnovitz, Len_AU
dc.date.accessioned2024-02-29T04:24:32Zen_AU
dc.date.available2024-02-29T04:24:32Zen_AU
dc.date.issued2022-07-15en_AU
dc.date.statistics2023-03-30en_AU
dc.description.abstractA fundamental and predictive understanding of mineral-fluid interactions is important for a wide range of energy topics including carbon sequestration, nuclear waste management and legacy contamination clean up. The properties of aqueous solution are altered by confinement, which can be present within natural geomaterials, e.g., in grain boundaries and nanopores. Mineral replacement reactions have been reported to proceed via grain boundaries possibly due to higher diffusion rates than in solids. In addition to confinement effects, chemomechanical effects such as crystallization pressure induced fracturing can also alter mineral-fluid interactions. To test the effects of porosity and grain boundaries on replacement in single component and impurity-containing systems we experimentally investigated the model system of limestone replacement by siderite by batch reactor experiments at 200°C from 2 to 120 days with FeCl2. Variation in initial microstructure and solid impurities were used to identify reaction controls. Changes in porosity were spatially resolved analyzed using inverse scattering techniques ((ultra) small angle neutron/X-ray scattering), and these were combined with imaging by scanning (SEM) and transmission electron microscopy (TEM). In high-porosity limestones replacement is rapid (complete replacement within 2 days), and transport controlled, whereas in low-porosity limestones elevated porosity throughout the whole rock volume was observed that was independent of the reaction rim. Image analysis showed widening of selected grain boundaries with increasing reaction time. This led to increased grain boundary width distributions that were observed as higher porosity by scattering methods. SEM imaging showed that nucleation of siderite crystals either at dolomite impurities within the limestone or other defects lead to exertion of crystallization pressure, widening grain boundaries, which led to formation of preferential transport pathways that limited replacement of solid impurity-containing limestone rocks. This highlights how chemomechanical effects can alter reaction pathways.en_AU
dc.identifier.citationWeber, J., Starchenko, V., Zhang, R., Ilavsky, J., Debeer-Schmitt, L., Mata, J., Kittrell, K., He, L., Chen, W.-R., Allard, L. F., Stack, A. G., & Anovitz, L. (2022). Chemomechanical influences during replacement of limestones by siderite. Paper presented to 2022 Goldschmidt Conference, 10-15 July, Honolulu, Hawaii, USA and Online. Retrieved from: https://conf.goldschmidt.info/goldschmidt/2022/meetingapp.cgi/Paper/11220en_AU
dc.identifier.conferenceenddate2022-07-15en_AU
dc.identifier.conferencename2022 Goldschmidt Conferenceen_AU
dc.identifier.conferenceplaceHonolulu, Hawaii, USA and Onlineen_AU
dc.identifier.conferencestartdate2022-07-10en_AU
dc.identifier.urihttps://conf.goldschmidt.info/goldschmidt/2022/meetingapp.cgi/Paper/11220en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15495en_AU
dc.language.isoenen_AU
dc.publisherGoldschmidten_AU
dc.subjectLimestoneen_AU
dc.subjectSideriteen_AU
dc.subjectCrystalsen_AU
dc.subjectRadioactive wastesen_AU
dc.subjectCardon sequestrationen_AU
dc.subjectGrain boundariesen_AU
dc.subjectMineralsen_AU
dc.subjectContaminationen_AU
dc.subjectSmall angle scatteringen_AU
dc.subjectTransmission electron microscopyen_AU
dc.titleChemomechanical influences during replacement of limestones by sideriteen_AU
dc.typeConference Presentationen_AU
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