Abstract
The dissolution of hydrated cement compounds controls the near-field chemistry in radwaste repositories containing cementitious materials. The dominant system in this respect is CaO-SiO{sub 2}-H{sub 2}O. Estimates of repository temperature indicate that this could be as high as 80{sup o}C in places. Therefore, in this work the thermodynamic properties and aqueous solubilities of compounds in the CaO-SiO{sub 2}-H{sub 2}O system have been determined at 80{sup o}C. The Gibbs energies of the solid phases have been expressed using a solid solution model, similar to that previously developed to describe data at 25{sup o}C, for the poorly crystalline gels that form in this system. The main effect of the higher temperature was found to be a reduction in pH. This is principally due to the different dissociation constant for water, with a smaller contribution from generally lower calcium solubilities at the higher temperature. Crystalline solid phases were observed to form, but these were not in equilibrium with the aqueous phase. (author).
Atkinson, A;
Hearne, J A;
[1]
Knights, C F
[2]
- AEA Industrial Technology, Harwell (United Kingdom)
- AEA Technology, Harwell (United Kingdom)
Citation Formats
Atkinson, A, Hearne, J A, and Knights, C F.
Aqueous chemistry and thermodynamic modelling of CaO-SiO{sub 2}-H{sub 2}O gels at 80{sup o}C.
United Kingdom: N. p.,
1991.
Web.
Atkinson, A, Hearne, J A, & Knights, C F.
Aqueous chemistry and thermodynamic modelling of CaO-SiO{sub 2}-H{sub 2}O gels at 80{sup o}C.
United Kingdom.
Atkinson, A, Hearne, J A, and Knights, C F.
1991.
"Aqueous chemistry and thermodynamic modelling of CaO-SiO{sub 2}-H{sub 2}O gels at 80{sup o}C."
United Kingdom.
@misc{etde_10120675,
title = {Aqueous chemistry and thermodynamic modelling of CaO-SiO{sub 2}-H{sub 2}O gels at 80{sup o}C}
author = {Atkinson, A, Hearne, J A, and Knights, C F}
abstractNote = {The dissolution of hydrated cement compounds controls the near-field chemistry in radwaste repositories containing cementitious materials. The dominant system in this respect is CaO-SiO{sub 2}-H{sub 2}O. Estimates of repository temperature indicate that this could be as high as 80{sup o}C in places. Therefore, in this work the thermodynamic properties and aqueous solubilities of compounds in the CaO-SiO{sub 2}-H{sub 2}O system have been determined at 80{sup o}C. The Gibbs energies of the solid phases have been expressed using a solid solution model, similar to that previously developed to describe data at 25{sup o}C, for the poorly crystalline gels that form in this system. The main effect of the higher temperature was found to be a reduction in pH. This is principally due to the different dissociation constant for water, with a smaller contribution from generally lower calcium solubilities at the higher temperature. Crystalline solid phases were observed to form, but these were not in equilibrium with the aqueous phase. (author).}
place = {United Kingdom}
year = {1991}
month = {Dec}
}
title = {Aqueous chemistry and thermodynamic modelling of CaO-SiO{sub 2}-H{sub 2}O gels at 80{sup o}C}
author = {Atkinson, A, Hearne, J A, and Knights, C F}
abstractNote = {The dissolution of hydrated cement compounds controls the near-field chemistry in radwaste repositories containing cementitious materials. The dominant system in this respect is CaO-SiO{sub 2}-H{sub 2}O. Estimates of repository temperature indicate that this could be as high as 80{sup o}C in places. Therefore, in this work the thermodynamic properties and aqueous solubilities of compounds in the CaO-SiO{sub 2}-H{sub 2}O system have been determined at 80{sup o}C. The Gibbs energies of the solid phases have been expressed using a solid solution model, similar to that previously developed to describe data at 25{sup o}C, for the poorly crystalline gels that form in this system. The main effect of the higher temperature was found to be a reduction in pH. This is principally due to the different dissociation constant for water, with a smaller contribution from generally lower calcium solubilities at the higher temperature. Crystalline solid phases were observed to form, but these were not in equilibrium with the aqueous phase. (author).}
place = {United Kingdom}
year = {1991}
month = {Dec}
}