Rate and mechanism of the reaction of silicates with cement pore fluids

Savage, David; Bateman, K.; Hill, Patrick; Hughes, Colin; Milodowski, Antoni E.; Pearce, Jonathan; Rae, E. I. C.; Rochelle, Christopher A.

doi:10.1016/0169-1317(92)90026-j

Cited by 83 publications

(54 citation statements)

References 13 publications

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“…Dissolution of the quartz by the cement waters enables the precipitation of CSH minerals such as tobermorite, hillebrandite, foshagite (Bérubé et al, 1990;Savage et al, 1992;Bateman et al, 1999), while dissolution of the Al-bearing micas and feldspars enables precipitation of CASH-phases as hydrogrossular in addition to CSH (Bérubé et al, 1990;Savage et al, 1992;Bateman et al, 1999;Hodgkinson and Hughes;. The Ca will thus be trapped by three phase types, i.e.…”

Section: Minerals and Reaction Pathways Involved In The Alkaline Distmentioning

confidence: 99%

Cement/clay interactions – A review: Experiments, natural analogues, and modeling

2006

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The concept of storing radioactive waste in geological formations calls for large quantities of concrete that will be in contact with the clay material of the engineered barriers as well as with the geological formation. France, Switzerland and Belgium are studying the option of clayey geological formations. The clay and cement media have very contrasted chemistries that will interact and lead to a degradation of both types of material. The purpose of this review is to establish an exhaustive list of laboratory experiments so as to identify the reaction sequences in the evolution of both the clay minerals and accessory minerals during their alteration in an alkaline environment. We review the data on clay dissolution kinetics in this environment, and include an invaluable study of natural analogues that allow one to correlate the phenomena in time. The available data and experiments make it possible to construct predictive numerical models. However, as the quality of the data is inhomogeneous, we recommend a continuation of the thermodynamic and kinetic data acquisition. It is obvious that the numerical modeling of the alkaline disturbance will be more relevant if it can combine the advantages of the different detailed models: mineralogical completeness, combined modeling of the clay and cement media, evolution of the porosity, consideration of the pCO 2 and all the surface reactions.

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Section: Minerals and Reaction Pathways Involved In The Alkaline Distmentioning

confidence: 99%

Cement/clay interactions – A review: Experiments, natural analogues, and modeling

2006

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“…Concerning K content, the loss of K from the solution corroborates its incorporation into the solid phase. Bérubé et al (1990) and Savage et al (1992), in a study on the interaction between minerals and an alkaline solution, also observed a progressive loss of calcium from alkaline solutions and a gain in Si as an initial step in the growth of CSH phases.…”

Section: Mineralogical and Chemical Modificationsmentioning

confidence: 99%

“…These analyses were performed to give an indication of the formation of the CSH phases, since these phases are often too finely grained and mixed with other phases to have their composition precisely determined by conventional XRD or EDX (Bérubé et al, 1990;Savage et al, 1992;Bateman et al, 1999;Hodgkinson and Hughes, 1999). The EDX analyses, which were made on each one of the surfaces indicated, are presented in figures 3c to 3h.…”

Section: Mineralogical and Chemical Modificationsmentioning

confidence: 99%

“…These studies demonstrated that the nature and extension of the modifications caused by the interactions of the minerals with the alkaline solution depend on the chemical/mineralogical composition of the initial solid material, the composition of the alkaline solution, and the alteration conditions, including temperature, period of exposure, and size of the solid sample (Gaucher and Blanc, 2006). Several studies show that the dominant interaction mechanism of minerals with alkaline solutions is the dissolution of primary aluminosilicates followed by precipitation of secondary phases of hydrated calcium silicates (CSH) (Bérubé et al, 1990;Savage et al, 1992;Hodgkinson and Hughes, 1999;Wieland and Loon, 2003). These CSH phases are formed by a combination of Al and Si dissolved from the sample and Ca from the alkaline solution.…”

Section: Introductionmentioning

confidence: 99%

“…Systematic study of this phenomenon began in the 1990s when the effect of alkaline solutions on the properties of isolated minerals was investigated (Bérubé et al, 1990;Savage et al, 1992). In the years that followed, alkaline alteration was evaluated for different materials comprising a wide range of commercial or natural clays and soils, as well as a combination of minerals, rocks and clay (Ramírez et al, 2002;Savage et al, 2002;Gaucher et al, 2004;Ramírez et al, 2005;Fernández et al, 2006;Savage et al, 2007;Yamaguchi et al, 2007;Rozalén et al, 2008;Fernández et al, 2009;Rozalen et al, 2009;Honty et al, 2010;Moyce et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Impact of an Alkaline Solution on the Chemistry, Mineralogy, and Sorption Properties of a Typic Rhodudult Soil

Calábria

Cota

Ladeira

2017

Rev. Bras. Ciênc. Solo

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Abstract:The preferred option for disposal of short-lived low and intermediate level radioactive wastes is a near surface disposal facility in which soil is one of the barriers that avoid radionuclide migration outside the controlled area. For construction of that kind of facility, concrete is widely used, and its interaction with water induces its degradation, resulting in a high pH solution. The alkaline solution may affect the near-field environment of radioactive waste repositories, including the soil, promoting mineralogical alterations that result in significant changes in key properties of materials, compromising their performance as safety components. In this study, a sample of a Brazilian Typic Rhodudult soil, previously investigated concerning its performance for Cs sorption, was subjected to interaction with the alkaline solution for 24 h and for 7, 14, and 28 days in order to evaluate the impact on its chemical, mineralogical, and sorption properties. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), atomic absorption spectrometry (AAS), scanning electron microscopy (SEM), and electron microprobe analysis were performed before and after each alteration period. Results indicated dissolution of minerals, such as kaolinite and quartz, associated with incorporation of K and Ca from the alkaline solution, likely resulting in the formation of hydrated calcium silicate phases (CSH), which are expected to be worse sorbents for alkaline elements (e.g., Cs) than the original minerals. The Kd values for Cs in the altered samples also decreased according to the alteration period, demonstrating that alkaline interaction effectively modifies the soil sorption properties for Cs.

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Diffusivity of dissolved silica in rock pore water at 25°C as characterized by through-diffusion experiments

Yokoyama

2013

Water Resour. Res.

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[1] The diffusivity of dissolved Si in rock pore water at 25 C was evaluated by throughdiffusion experiments for three types of rock (Fontainebleau sandstone, Berea sandstone, and Tenjyosan rhyolite). Comparisons of the effective diffusion coefficients of Si, K 1 , and Cl 2 (D e;Si , D e;K 1 , and D e;Cl 2 ) at neutral pH (unbuffered) showed that the D e;Si values obtained for the three rocks were 2.3-3.0 times smaller than those of D e;K 1 and D e;Cl 2 . The small value of D e;Si compared with D e;K 1 and D e;Cl 2 is primarily attributed to the difference in the diffusion coefficients of K 1 , Cl 2 , and Si in free water (a factor of 1.7) but might be also partly due to the precipitation of Si in the pores. The chemical form of the dissolved Si is altered depending on the solution pH. To examine how the diffusivity of Si is affected by its chemical form, the D e;Si values were also determined at pH 6 and pH 11 (buffered solutions containing 0.5 M NaCl) using a Fontainebleau sandstone sample. The dominant chemical forms of Si predicted from thermodynamic calculations are an electrically neutral monomer (Si(OH) 4 ) at pH 6 and an anionic monomer (SiO(OH) 32 ) with a certain amount of anionic multimers (e.g., dimer, trimer, tetramer) at pH 11 (total Si concentration 20.4 mM). The values of D e;Si obtained at pH 6 and pH 11 were quite similar (1.94 3 10 27 to 1.97 3 10 27 cm 2 s 21 ), and D e;Si was hardly affected by the change in the charge state and the presence of multimeric species.

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Rate and mechanism of the reaction of silicates with cement pore fluids

Cited by 83 publications

References 13 publications

Cement/clay interactions – A review: Experiments, natural analogues, and modeling

Cement/clay interactions – A review: Experiments, natural analogues, and modeling

Impact of an Alkaline Solution on the Chemistry, Mineralogy, and Sorption Properties of a Typic Rhodudult Soil

Diffusivity of dissolved silica in rock pore water at 25°C as characterized by through-diffusion experiments

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