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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/25872

Title: Incorporating Cs and Sr into blast furnace slag inorganic polymers and their effect on matrix properties
Authors: Vandevenne, Niels
Iacobescu, Remus Ion
Pontikes, Yiannis
Carleer, Robert
Thijssen, Elsy
Gijbels, Katrijn
Schreurs, Sonja
Schroeyers, Wouter
Issue Date: 2018
Status: In Press
Abstract: Minimizing harmful effects to the environment in waste-management practices requires continuous innovation. This is especially important in the field of radioactive waste management. Alternatives to the commonly used ordinary Portland cement matrices are being increasingly studied for improved immobilisation purposes. The development of inorganic polymers (IP) from industrial residues has been successfully studied for the immobilisation of caesium (Cs+) and strontium (Sr2+). However, knowledge of the effect of these introduced elements on the IP-matrix is scarce, especially considering that studied effects are dependent on the IP-precursor characteristics and the form in which the Cs+ and Sr2+ are introduced. In this study, IPs containing varying amounts of CsNO3 and Sr(NO3)2 were developed to study the effect of the introduced elements on the IP-characteristics. IP-samples were developed from ground granulated blast furnace slag (GGBFS) and 6 M NaOH activating solution. Cs+ and Sr2+ were added to account for 0.5, 1 and 2 wt% of the total IP-mass. Throughout the entire study, Cs+-addition showed no significant effects on the studied parameters. Calorimetric results showed that Sr2+ severely affects reaction kinetics, consuming hydroxide ions necessary for the alkali activation reaction. Sr2+-addition also caused a severe decrease in compressive strength, increased calcium leaching, and decreased sodium and hydroxide leaching. Micro-chemical analyses showed that Cs+ is almost fully incorporated in the formed IP-matrix, while Sr2+ mainly precipitates as Sr(OH)2 in concentrated regions throughout the IP-structure. The findings presented in this paper give insights on the effect of contaminant elements on the immobilising matrix.
URI: http://hdl.handle.net/1942/25872
DOI: 10.1016/j.jnucmat.2018.02.023
ISSN: 0022-3115
Category: A1
Type: Journal Contribution
Appears in Collections: Research publications

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