Dissertation
SYSTEMATIC INVESTIGATION OF EFFECTS OF IRON ON CRYSTALLIZATION OF IRON-CONTAINING SODIUM ALUMINOSILICATE GLASSES
Doctor of Philosophy (PhD), Washington State University
01/2019
Handle:
https://hdl.handle.net/2376/112411
Abstract
Within the Hanford high-level waste (HLW), iron is a major component whose concentration varies from ~5 to 30 wt% Fe2O3. Moreover, iron plays a key role in natural silicates that have been studied as analogues for nuclear waste glasses to understand their long-term durability. This work systematically studies the role of iron in crystallization behavior of simplified and simulant HLW glass compositions, with an emphasis on the formation of the nepheline phase that undesirably crystallizes during the vitrification of Hanford HLW. Mineralogically-important sodium iron silicate compositions were also studied to understand their structure and crystallization behavior. A variety of materials characterization techniques were employed including X-ray diffraction, thermal analysis, vibrating sample magnetometry, electron probe microanalysis, and Raman and Mössbauer spectroscopies. It was discovered that iron can markedly incorporate into nepheline phase at Al sites (up to ~20 wt% Fe2O3 of the total nepheline composition), and thus can promote the crystallization of nepheline over its high-temperature polymorph, carnegieite, when present in smaller amounts (i.e., <10 wt% Fe2O3 in NaAl(1-x)FexSiO4). Additionally, most of the iron cations (>75%) in the studied glasses occur as [4]Fe3+, and its fraction increases with increasing the iron concentration.
Iron oxides as the main recorders of the ancient geomagnetic field in natural samples were also studied in this work. Such magnetic minerals, in which iron is the crucial component, makes it possible to date archaeological objects using paleomagnetic methods. Archaeomagnetic dating of vitrified Broborg hillfort materials as an anthropogenic analogue for nuclear waste glasses is discussed.
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Details
- Title
- SYSTEMATIC INVESTIGATION OF EFFECTS OF IRON ON CRYSTALLIZATION OF IRON-CONTAINING SODIUM ALUMINOSILICATE GLASSES
- Creators
- Mostafa Ahmadzadeh
- Contributors
- John Stuart McCloy (Advisor)Min-Kyu Song (Committee Member)Xiaofeng Guo (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Materials Science and Engineering Program
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 211
- Identifiers
- 99900581504901842
- Language
- English
- Resource Type
- Dissertation