Effect of Cr2O3 on the HLW Iron Phosphate Glass Wasteforms

Abstract

The chemical durability, and structure of iron phosphate glasses containing 70 wt% of a simulated high level nuclear waste (HLW), doped with different amounts of Cr2O3 were investigated. All of these iron phosphate glassy and crystallized wasteforms possess an outstanding chemical durability as measured by their small dissolution rate (10-9 g/(cm2·min)) in deionized water at 90°C for 128 days, their low normalized mass release as determined by the Product Consistency Test (PCT) and a barely measurable corrosion rate of < 0.1 g/(m2·d) after 7 days at 200°C by the Vapor Hydration Test (VHT) can meet all current DOE requirements for chemical durability. the PCT results show that the Cr2O3 doping into IP70W samples can suppress the clement release from both the glassy and crystallized samples and improve the chemical durability. the solubility limit for Cr2O3 in the iron phosphate melts estimated at 4.1 wt%, is at least 3 times larger than that for borosilicate glasses. the results from FTIR and DTA show that the structure of IP glass wasteforms has no significant changes when Cr2O3 doped into IP70W samples. Mossbauer spectra show that there is a redox reaction between Fe and Cr ions during the melting process and that the ratio of Fe2+/Fe3+ increases with the increase of Cr2O3 amount in the compositions. These Cr6+ ions formed can improve the chemical durability of the glass wasteforms.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Chemical durability measurement; Chrome oxide; Iron phosphate glass; Nuclear waste treatment

International Standard Serial Number (ISSN)

1000-324X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Science Press, All rights reserved.

Publication Date

01 Jul 2005

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