Catalytic effect of some oxides on calcination of sodium nitrate
- Univ. of the Negev, Beer-Sheva (Israel)
The calcination process used for sodium nitrate could be the most important part of the liquid-waste calcination process used in high-level-waste (HLW) disposal. A French process that involves conversion of the solution of nitrate fission products into a solid mixture of oxides and undecomposed nitrates. These products are then mixed with a glass-making mixture (called a frit) in an induction melting pot. In 1984, Utake et.al., suggested that the use of the Sol-Gel technique to decrease the calcination temperature of NaNO{sub 3}. In this work, we used the thermal-analysis technique to study the catalytic effect of some glass network formers like SiO{sub 2}, B{sub 2}O{sub 3}, and of some network modifiers like Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, MgO, TiO{sub 2}, ZnO. The best effect was achieved by adding 20% diatomaceous earth (Kieselguhr) and 20% B{sub 2}O{sub 3}. In that case, the calcination temperature onset decreased from 780{degrees}C to 565{degrees}C. The advantages of this process are as follows: (1) The proposed additives (Kieselguhr and B{sub 2}O{sub 3}) are glass network formers that have to be added anyway in the next process step; (2) In the proposed process, no sodium is added, and the only process change suggested is that the glass formers (or part of them) should added at the calcination step, rather than at the glass-melting step; (3) The proposed modification is easily achieved and is expected to improve the homogenization of the final product.
- OSTI ID:
- 62194
- Report Number(s):
- CONF-921101-Vol.294; TRN: 95:002922-0010
- Resource Relation:
- Conference: 16. Materials Research Society (MRS) fall meeting, Boston, MA (United States), 30 Nov - 5 Dec 1992; Other Information: PBD: 1993; Related Information: Is Part Of Scientific basis for nuclear waste management XVI; Interrante, C.G. [ed.] [Nuclear Regulatory Commission, Washington, DC (United States)]; Pabalan, R.T. [ed.] [Southwest Research Inst., San Antonio, TX (United States)]; PB: 959 p.
- Country of Publication:
- United States
- Language:
- English
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