Glass - Back to the Future!



Presenting Author:
Mária Chromcíková
<maria.chromcikova@tnuni.sk>

article posted 4 Mar 2016


Mária Chromcíková is head of the laboratory of thermal methods at the VILA Glass Centre.






Thermodynamic model and selected physical properties of glasses for Chrompik vitrification

Mária Chromcíková*1, Marek Liska1, Magdaléna Teplanová1, Jan Machácek2, and Branislav Hruska1

The present contribution deals with the structure and physical properties (molar volume, thermal expansion, glass transition temperature, chemical durability) of boro-alumino-silicate glasses and glassforming melts used for vitrification of the chrompic radioactive waste. Chrompic is a mixture of potassium chromate and potassium dichromate obtained during cooling of fuel elements after their removal from reactor A1 of NPP Jaslovské Bohunice [1,2]. The compositional dependence of physical properties of glasses with chemical composition close to the contemporary used glass for chrompic vitrification was studied. The chemical composition of 7-components studied glasses can be characterized (in weight %) as:

Thermodynamic model of Shakhmatkin and Vedishcheva [3] was constructed for each studied glass composition. Within the model the glasses were considered as an ideal solution of 55 components with the stoichiometry given by the composition of stable crystalline phases of the 7-component oxide system. The components with negligible equilibrium molar amounts found in all studied glasses were not considered in the model. Such way only 14 components were retained. The compositional dependence of studied physical properties was described by multilinear form of equilibrium molar amounts obtained from the thermodynamic model. Only the statistically significant terms were retained in the resulting equations. Using the statistical methods the dependences obtained by using the equilibrium molar amounts were compared with the obtained by using the molar fractions of individual (unreacted) oxides. It was shown that the thermodynamic model described the studied compositional dependencies with better accuracy.

References

1. http://www.javys.sk/sk/jadrove-zariadenia/technologie-spracovania-a-upravy-rao/vitrifikacna-linka (2014).

2. M.I. Ojovan, W.E. Lee: An introduction to nuclear waste immobilization. Elsevier, Oxford 2005.

3. N.M Vedishcheva, B.A. Shakhmatkin, C.A. Wright, J. Non-Cryst. Solids. 345-346 (2004) 39-44.

Acknowledgement:

This work was supported by the Slovak Grant Agency for Science under the grant VEGA 2/0088/16 & 1/0386/16.

Institutions:

1. Vitrum Laugaricio - Joint Glass Center of IIC SAS, TnUAD, and FChPT STU, Studentská 2, Trencín, SK-91150, Slovakia

2. University of Chemistry and Technology, Technická 5, Prague, CZ-166 28, Czech Republic