Thermal properties of 60P2O5-20Fe2O3-20Al2O3 glass for salt waste immobilization

Abstract

Vitrification is the most effective method of hazardous waste immobilization. Toxic elements are incorporated into a glass structure. Iron alumino-phosphate glasses are presently being considered as a matrix for storage of a radioactive waste which cannot be vitrified using conventional borosilicate waste glasses. Influence of Na2SO4 as a one of components such the waste on thermal properties and crystallization ability of 60P2O5-20Fe2O3-20Al2O3 glass was studied. It was observed that Na2SO4 decreases transformation temperature and increases ΔC p. The glass characteristic temperatures, glass crystallization ability and crystallizing phases were determined. Na2SO4 increases the glass crystallization ability which could be related with ΔC p heat capacity accompanying glass transition changes. The glass internal structure rebuilding accompanying the sodium content increase is considered. The obtained results were compared with structural model previously developed for 60P2O5-40Fe2O3 glass and showed the structural similarity between these glasses.