Griffith, Christopher S., Sebesta, Ferdinand, Hanna, John V., Yee, Patrick, Drabarek, Elizabeth, Smith, Mark E. and Luca, Vittorio. (2006) Tungsten bronze-based nuclear waste form ceramics. Part 2: Conversion of granular microporous tungstate-polyacrylonitrile (PAN) composite adsorbents to leach resistant ceramics. Journal of Nuclear Materials, Vol.358 (No.2-3). pp. 151-163. ISSN 0022-3115

Full text not available from this repository.

Abstract

Conversion of a granular molybdenum-doped, hexagonal tungsten bronze (MoW-HTB)-polyacrylonitrile (PAN) composite adsorbent to a leach resistant ceramic waste form capable of immobilizing adsorbed Cs+ and Sr2+ has been achieved by heating in air at temperatures in the range 600-1200 degrees C. Thermal treatment of the Cs- and Sr-loaded composite material at 1000 degrees C was sufficient to invoke a 60% reduction in volume of the composite while still retaining its spherical morphology. Cs-133 MAS NMR studies of this sample suite at 9.4 T and 14.1 T showed that multiple Cs sites are present throughout the entire thermal treatment range. Scanning electron microscopy investigations of the phase assemblages resulting from thermal treatment demonstrated that the full complement of Cs, and the majority of Sr, partitions into HTB phases (A(0.16-0.3)MO(3); A = Cs+, Sr2+ and Na+; M = Mo, W). The potentially reducing conditions resulting from the removal of the PAN matrix or the presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not retard the formation of the high temperature HTB phases. The fraction of Cs+ and Sr2+ leached from the tungstate phase assemblages was superior or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = approximate to 8 x 10(-5); rate = < 1.2 x 10(-4) g/m(2)/day) and strontium titanate (SrTiO3; f = 3.1 x 10(-3); rate = 2.63 x 10(-4) g/m(2)/day), respectively, using a modified PCT test in Millipore water at 90 degrees C. Furthermore, where aggressive leaching conditions were employed (0.1 M HNO3; 150 degrees C; 4 days), the tungstate phase assemblages displayed leach resistance almost two orders of magnitude greater than the reference phases.

Item Type:	Journal Article
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) Q Science > QC Physics T Technology > TN Mining engineering. Metallurgy
Divisions:	Administration > Vice Chancellor's Office Faculty of Science > Physics
Journal or Publication Title:	Journal of Nuclear Materials
Publisher:	Elsevier Science BV
ISSN:	0022-3115
Official Date:	30 November 2006
Dates:	Date Event 30 November 2006 Published
Volume:	Vol.358
Number:	No.2-3
Number of Pages:	13
Page Range:	pp. 151-163
Identifier:	10.1016/j.jnucmat.2006.06.018
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
URI:	http://wrap.warwick.ac.uk/id/eprint/32779

Data sourced from Thomson Reuters' Web of Knowledge

Request changes or add full text files to a record

Actions (login required)

View Item