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EFFECTS OF TEMPERATURE, pH, AND IRON/CLAY AND LIQUID/CLAY RATIOS ON EXPERIMENTAL CONVERSION OF DIOCTAHEDRAL SMECTITE TO BERTHIERINE, CHLORITE, VERMICULITE, OR SAPONITE
- Source :
- Clays and Clay Minerals, Clays and Clay Minerals, Clay Minerals Society, 2010, 58 (2), pp.280-291. ⟨10.1346/CCMN.2010.0580212⟩, Clays and Clay Minerals, Clay Minerals Society, 2010, 58 (2), pp.280-291, Clays and Clay Minerals, Clay Minerals Society, 2010, 58 (2), pp.280-291. 〈10.1346/CCMN.2010.0580212〉, Clays and Clay Minerals, 2010, 58 (2), pp.280-291. ⟨10.1346/CCMN.2010.0580212⟩
- Publication Year :
- 2010
- Publisher :
- HAL CCSD, 2010.
-
Abstract
- International audience; In deep geological repositories for high-level nuclear wastes, interactions between steel canisters and clay-rich materials may lead to mineralogical transformations with a loss of the confining properties of the clays. Experiments simulating the conversion of smectite to Fe-rich clay phases in contact with Fe metal have been carried out to evaluate such a possibility by taking into account the effects of a series of critical parameters, including temperature, pH, and Fe/clay (Fe/C) and liquid/clay (L/C) ratios. The mineralogical and chemical transformations observed in these experiments have been compared with data from the literature, and subsequently used to propose a conceptual model for the main mineralogical transformations which can be expected in clay formations surrounding high-level nuclear waste repositories. In the presence of Fe metal and under low oxygen fugacity ( 5: dioctahedral smectite (di-sm) ? 7 A˚ Fe-rich phase (berthierine, odinitecronstedtite) for large Fe/C ratios (>0.5), or di-sm ? Fe-rich di-sm + Fe-rich trioctahedral smectite (tri-sm) for small Fe/C ratios (0.1); (2) up to 150ºC, under alkaline pH (1012), and L/C > 5: di-sm ? Fe di-sm (Npalygorskite) for a small Fe/C ratio (0.1); (3) at 300ºC, Fe/C = 0.1, and L/C > 5: di-sm ? Fe-rich saponite ? trioctahedral chlorite + feldspar + zeolite (near-neutral pH); di-sm ? Fe-rich vermiculite + mordenite (pH 1012). Low temperatures (
- Subjects :
- Nuclear Waste
[SDE.MCG]Environmental Sciences/Global Changes
Analytical chemistry
[SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography
Soil Science
Mineralogy
Vermiculite
020101 civil engineering
02 engineering and technology
engineering.material
010502 geochemistry & geophysics
Feldspar
01 natural sciences
0201 civil engineering
Fe Metal
chemistry.chemical_compound
Geochemistry and Petrology
[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry
Earth and Planetary Sciences (miscellaneous)
medicine
Fugacity
Saponite
[ SDU.STU.MI ] Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Chlorite
[SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology
ComputingMilieux_MISCELLANEOUS
0105 earth and related environmental sciences
Water Science and Technology
Berthierine
Palygorskite
[ SDU.STU.GC ] Sciences of the Universe [physics]/Earth Sciences/Geochemistry
Silicate
[ SDE.MCG ] Environmental Sciences/Global Changes
chemistry
visual_art
visual_art.visual_art_medium
engineering
Smectite
Clay minerals
Geology
[ SDU.STU.AG ] Sciences of the Universe [physics]/Earth Sciences/Applied geology
medicine.drug
[SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Subjects
Details
- Language :
- English
- ISSN :
- 00098604
- Database :
- OpenAIRE
- Journal :
- Clays and Clay Minerals, Clays and Clay Minerals, Clay Minerals Society, 2010, 58 (2), pp.280-291. ⟨10.1346/CCMN.2010.0580212⟩, Clays and Clay Minerals, Clay Minerals Society, 2010, 58 (2), pp.280-291, Clays and Clay Minerals, Clay Minerals Society, 2010, 58 (2), pp.280-291. 〈10.1346/CCMN.2010.0580212〉, Clays and Clay Minerals, 2010, 58 (2), pp.280-291. ⟨10.1346/CCMN.2010.0580212⟩
- Accession number :
- edsair.doi.dedup.....f0a72b6e2644dd574c06ba2f7f4461bc