Skip to main content Accessibility help
×
Home

Fixation of Cesium by Calcium Aluminosilicate Hydrates

  • Susan L. Hoyle (a1) and Michael W. Grutzeck (a1)

Abstract

Recent work by the authors has demonstrated that cesium was being incorporated in a hydrated phase as their cement-based waste forms cured. The objective of the present study was to identify the hydrated phases responsible for the observed cesium incorporation. Four calcium aluminosilicate glasses having a 1:2 Al2 O3 /CaO ratio and a 25–70 mole % silica content were mixed with ˜0.3 molar CsOH or CsCl solutions (water/solid ratio = 10) and allowed to hydrate at 38° and 90°C for periods up to 90 days. Paste equivalent samples, having a water/solid ratio of 1.0 were also prepared to gauge the cementing properties of these mixtures. Solutions were analyzed for Ca, Al, Si, and Cs while solids were characterized using x-ray powder diffraction and scanning electron microscopy.

Glasses exposed to the CsOH solution were more reactive than their counterparts exposed to the CsCl solution. In addition, reactivity as well as crystallinity seemed to be higher at 90° than at 38°C. At least two cesium-containing zeolites were identified in the 90°C CsOH solution experiment: A cesium-containing wairarkite analogue and possibly another cesium-containing zeolite unidentified at this time. The relatively complete removal of cesium from the solution, in one case, as well as the fact that the mixtures are self-cementing suggests that the glasses may be “engineered” to serve as overpack material in a deep-seated geologic repository.

Copyright

References

Hide All
1. Crawford, R.W., Glasser, F.P., Rahman, A.A., Angus, M.J. and McCulloch, C.E., “Diffusion Mechanisms and Factors Affecting Leaching of Cesium-134 from Cement-based Waste Matrices,” Radioactive Waste Management and the Nuclear Fuel Cycle 6., 177196 (1985).
2. Crawford, R.W., McCulloch, C., Angus, M., Glasser, F.P. and Rahman, A.A., “Intrinsic Sorption Potential of Cement 134Cs,” Cement and Concrete Research 14,594599 (1984).
3. McCulloch, C.E., Rahman, A.A., Angus, M.J., Glasser, F.P. and Crawford, R.W., “Immobilization of Cesium in Cement Containing Reactive Silica and Pozzolans,” Advances in Ceramics- Nuclear Waste Management, Wicks, G.G. and Ross, W.A. (eds.), Vol.8, pp. 113128, American Ceramic Society, Columbus, OH (1984).
4. Hoyle, S. and Grutzeck, M.W., “Effects of Phase Composition on the Cesium Leachability of Cement-Based Waste Forms,” Waste Management 1986, Proceedings of Waste Isolation; Technical Programs and Public Education, Vol.3, pp. 491–496, University of Arizona (1986).
5. Hoyle, S. and Grutzeck, M.W., “Effect of Pore Solution Composition on Cesium Leachability of Cement Based Waste Forms”, Scientific Basis for Nuclear Waste Management, Bates, J.K. and Seefeldt, W.B. (eds.), Vol.84, pp. 309317, Materials Research Society, Pittsburgh, PA (1987).
6. JCPDS, Joint Committee of Powder Diffraction Standards, 1601 Park Lane, Swarthmore, PA (1985).
7. Diamond, S., “Cement Paste Microstructure–An Overview at Several Levels”, in Hydraulic Cement Pastes: Their Structure and Properties, Cement Concrete Assn., Wexham Springs, England (1976).

Related content

Powered by UNSILO

Fixation of Cesium by Calcium Aluminosilicate Hydrates

  • Susan L. Hoyle (a1) and Michael W. Grutzeck (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.