Title

The Structure and Properties of Cesium Loaded Mo-Fe-Phosphate Glasses

Abstract

Chemically durable iron phosphate glasses are promising candidates for hosting nuclear wastes containing constituents like Cs2O and MoO3 that have lower solubility in more conventional borosilicate glasses. In this work, two series of Cs-Mo-Fe-phosphate glasses were prepared and characterized. For glasses in Series A (xCs2O·(100-x)·(15MoO3·22.5Fe2O3·62.5P 2 O 5 ), x = 0, 7.5, 15.0, 22.5), increasing Cs2O contents increase the molar volume and decrease the glass transition temperature. Raman spectroscopy reveals that adding Cs2O breaks down linkages between MoO6 octahedra, replacing Mo—O—Mo and Mo=O bonds with Mo-O-Cs+ bonds. Phosphate anion chromatography reveals that adding Cs2O has little effect on the phosphate anion distributions. For glasses in Series B (15Cs 2 O·yMoO3·(28.75-y)F2O3·56.25P 2 O 5 , y = 0, 5.75, 11.50, 17.25, 23.00, 28.75), the glass transition temperature decreases and the aqueous dissolution rates increase when MoO3 replaces Fe2O3. The formation of isolated MoO6 octahedra with Mo-O- Cs+ bonds results in an increase in the average phosphate anion-length in the MoO3-rich glasses. Mössbauer spectroscopy indicates that ferric ions dominate in both series, and that the average Fe-coordination number increases with increasing Cs2O content (series A) and with increasing MoO3 content (series B).

Department(s)

Mining and Nuclear Engineering

Second Department

Materials Science and Engineering

Comments

This work was supported by the US Department of Energy under the contract number of DE-SC0011906.

Keywords and Phrases

Cs2O; Iron-phosphate glass; Isolated MoO6 octahedra; Mossbauer spectroscopy; Nuclear waste vitrification

International Standard Serial Number (ISSN)

0022-3093

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2019 Elsevier B.V., All rights reserved.

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