Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-03T00:01:46.725Z Has data issue: false hasContentIssue false
  • English
  • Français

Iodine Waste Forms: Calcium Aluminate Hydrate Analogues

Published online by Cambridge University Press:  26 February 2011

Dale R. Brown  and
Michael W. Grutzeck
Dale R. Brown
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
Michael W. Grutzeck
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
Get access

Abstract

Phase relations in the system 3CaO·AI2O3-CaSO4-CaI2-H2O in equilibrium with excess water were established by means of room temperature bottle hydration of various bulk chemistries in the system. Starting with end members ettringite (3CaO·Al2O3·3CaSO4·32H2O) and tetracalcium aluminate monosulfate-12-hydrate (3CaO·Al2O3-CaSO4-12H2O), iodine-substituted analogue phases were synthesized which containe increasingly greater percentages of iodine. The iodine-substituted ettringite was found to be unstable whereas the iodine-substituted monosulfate formed readily. SEM, wet chemistry, IR, and x-ray diffraction characterization of the latter phase suggest that its formula is 3CaO·Al2O3·Ca(IO3)2·2H2O. Cement pellets containing this “Afm” iodine-substituted phase were subjected to a modified MCC-1 static leach test. Although the normalized iodine leach rate was relatively high when compared with AgI encapsulated in portland Type III cement, this same leach rate was approximately equal to the rates that have been reported for Ba(IO3)2, Ca(IO3)2, and Hg(IO3)2 in portland cement. The normalized iodine leach rate obtained also was found to be roughly comparable to that given for I-sodalite in cement. Diffusion is indicated as the primary leach mechanism, becoming dominant after the first three days of leaching.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 44: Symposium N – Scientific Basis for Nuclear Waste Management VIII , 1984 , 911
Copyright
Copyright © Materials Research Society 1985

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Burger, L.L., Scheele, R.D., and Weimers, K.D.. Selection of a Form for Fixation of Iodine-129, PNL-4045, Pacific Northwest Laboratory,Richland, Washington, 1981.Google Scholar
[2] Kuzel, H.J.. “X-Ray Investigations of Some Complex Calcium Aluminate Hydrates and Related Compounds,” Proceedings of the Fifth International Symposium on the Chemistry of Cement, Vol. 2, p. 92. The Cement Association of Japan, Tokyo, Japan,1968.Google Scholar
[3] Houtepen, C.J.M. and Stein, H.N.. “The Enthalpies of Formation and of Dehydration of Some AFm Phases with Singly Charged Anions,” Cement and Concrete Research, 6, 651 (1976).Google Scholar
[4] Bel, F. Le and Grasland, G.. “Quaternary Calcium Aluminate Hydrates: Crystal Structure of Calcium Aluminate Monobromide Hydrate,” Proceedings of the Fifth International Symposium on the Chemistry of Cement, Vol. 2, p 79. The Cement Association of Japan, Tokyo, Japan, 1968.Google Scholar
[5] Materials Characterization Center. Nuclear Waste Materials Handbook, DOE/TIC-11400, Pacific Northwest Laboratory, Richland, Washington, 1981.Google Scholar
[6] Visser, J.W.. “A Fully Automatic Program for Finding the Unit Cell from Powder Data,” Journal of Applied Crystallography, 2, 89 (1969).Google Scholar
[7] Morgan, M.T., Moore, J.G., Devaney, H.E., Rogers, G.C., Williams, C., and Newman, E.. “The Disposal of Iodine-129,” Scientific Basis for Nuclear Waste Management, Materials Research Society Symposia Proceedings, Vol. 1 p.453. Plenum Press, New York, NY, 1979.CrossRefGoogle Scholar
[8] Clark, W.E.. “The Isolation of Radioiodine with Portland Cement. Part 1: Scoping Leach Studies,” Nuclear Technology, 36, 215 (1977).Google Scholar
[9] Barnes, M.W., Scheetz, B.E., Wakeley, L.D., Atkinson, S.D., and Roy, D.M.. “Stability of I and Sr Radiophases in Cement Matrices,” Scientific Basis for Nuclear Waste Management, Materials Research Society Symposia Proceedings, Vol. 6, p. 147. Elsevier Science Publishing Co., Inc., New York, NY, 1982.Google Scholar