Effect of Cr₂O₃ on the HLW Iron Phosphate Glass Wasteforms
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.
W. Huang et al., "Effect of Cr₂O₃ on the HLW Iron Phosphate Glass Wasteforms," Wuji Cailiao Xuebao/Journal of Inorganic Materials, vol. 20, no. 4, pp. 842-850, Science Press, Jul 2005.
Materials Science and Engineering
Keywords and Phrases
Chemical durability measurement; Chrome oxide; Iron phosphate glass; Nuclear waste treatment; Chromium compounds; Corrosion resistance; Differential thermal analysis; Durability; Fourier transform infrared spectroscopy; Heat treatment; Radioactive waste disposal; Radioactive wastes; X ray diffraction analysis
International Standard Serial Number (ISSN)
Article - Journal
© 2005 Science Press, All rights reserved.
01 Jul 2005