The effects of glass doping, temperature and time on the morphology, composition, and iron redox of spinel crystals
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Office of River Protection, Richland, WA (United States)
Precipitation of large crystals/agglomerates of spinel and their accumulation in the pour spout riser of a Joule-heated ceramic melter during idling can plug the melter and prevent pouring of molten glass into canisters. Thus, there is a need to understand the effects of spinel-forming components, temperature, and time on the growth of crystals in connection with an accumulation rate. In our study, crystals of spinel [Fe, Ni, Mn, Zn, Sn][Fe, Cr]₂O₄ were precipitated from simulated high-level waste borosilicate glasses containing different concentrations of Ni, Fe, and Cr by heat treating at 850 and 900°C for different times. These crystals were extracted from the glasses and analyzed with scanning electron microscopy and image analysis for size and shape, with inductively coupled plasma-atomic emission spectroscopy and atom probe tomography for concentration of spinel-forming components, and with wet colorimetry and Mössbauer spectroscopy for Fe²⁺/Fetotal ratio. High concentrations of Ni, Fe, and Cr in glasses resulted in the precipitation of crystals larger than 100 µm in just two days. Crystals were a solid solution of NiFe₂O₄, NiCr₂O₄, and -Fe₂O₃ (identified only in the high-Ni-Fe glass) and also contained small concentrations of less than 1 at% of Li, Mg, Mn, and Al.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1208787
- Report Number(s):
- PNNL-SA-100009; 830403000
- Resource Relation:
- Conference: Advances in Materials Science for Environmental and Energy Technologies III, October 27-31, 2013, Montreal, Quebec, Canada. Ceramic Transactions, 250:147-156
- Country of Publication:
- United States
- Language:
- English
Similar Records
Predictive modeling of crystal accumulation in high-level waste glass melters processing radioactive waste
Evaluation of Crystal Accumulation in High Level Waste Glasses with Research-Scale Melter