Cheol-woon Kim

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James Marrow

University of Oxford

Dr. Sumon Saha

Bangladesh University of Engineering & Technology

Martina Ulvrova

Swiss Federal Institute of Technology (ETH) & University of Zurich

Sudhakar Rao Gorja

Paul Scherrer Institute

Pedro Guerra

Universidad Politécnica de Madrid

Balakrishna Palanki

Jawaharlal Nehru Technological University Hyderabad

Sourav Saha ( সৌরভ সাহা )

Bangladesh University of Engineering and Technology

Mara Reis

Pontificia Universidade Catolica de Minas Gerais

Daniel Valentino

University of California, Los Angeles

Sachin Kalsi

Chandigarh University Gharuan

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Iron Phosphate Glass for Immobilization of Hanford LAW

Ceramic transactions, 2004

Three iron phosphate glasses containing up to 35 wt% of a high sulfur Hanford LAW simulant were s... more Three iron phosphate glasses containing up to 35 wt% of a high sulfur Hanford LAW simulant were successfully melted in electric furnaces at 1150-1250°C for 2-3 hours. No sulfate salt segregation was found in the glass when examined by SEM. The glass retained up to 73% of the sulfur originally present in the waste, which was equivalent to 2.4 wt% SO 3 on a target glass oxide basis. This suggests that the waste loading in the iron phosphate glasses will not be limited by the SO 3 content of the LAW as it typically is by the baseline technology for Hanford LAW treatment. The chemical durability of the iron phosphate glasses was determined by the product consistency test (PCT) and the vapor hydration test (VHT). The mass release of sodium from both annealed and canister centerline cooled (CCC), partially crystallized iron phosphate wasteforms after the PCT at 90°C for 7 days was below the current DOE specification for LAW. The VHT alteration rates (200°C for 7 days) of the iron phosphate glasses for both annealed and CCC treated samples were also significantly lower than the current DOE limit and those of standard borosilicate glasses. All of the iron phosphate wasteforms met all of the existing requirements for aqueous chemical durability and the crystallization that occurred during CCC treatment did not reduce the chemical durability. Iron phosphate glasses were successfully melted in a hot-wall induction furnace and in a microwave oven. These melting processes avoid any corrosion problems associated with metal electrodes needed for joule heated melting

Redox effects on the structure and properties of Na-Mo-Fe-phosphate glasses

Journal of Non-crystalline Solids, Apr 1, 2021

Na-Mo-Fe-phosphate glasses were prepared with reducing and oxidizing raw materials and the effect... more Na-Mo-Fe-phosphate glasses were prepared with reducing and oxidizing raw materials and the effects of the different Fe 2+ /Fe 3+ and Mo 5+ /Mo 6+ ratios on glass structure and properties were determined. M össbauer spectroscopy confirms significantly greater concentrations of Fe 2+ ions in the reduced glasses and distorted Fe 3+ O 4 sites preferred over the Fe 3+ O 6 sites in the oxidized glasses. Raman spectroscopy reveals the presence of isolated Mo 6+ O 6 sites in the oxidized glasses, and highly distorted Mo 5+ O 5 sites in reduced Mo-rich glasses. The presence of specific Fe-and Mo-polyhedra is correlated with the average phosphate anion length, as characterized by high-pressure liquid chromatography. Generally, for the similar compositions, oxidized glasses have greater molar volumes than the reduced glasses, associated with the formation of isolated Mo 6+ O 6 octahedra and the absence of highly crosslinked Mo 5+ OPO 4 units. T g increases with increasing Fe 3+ fractions in the Fe-rich glasses, whereas for the Mo-rich glasses, T g increases with greater Mo 5+ fractions.

Cheol-woon Kim

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