Abstract
SYNTHESIS AND CHARACTERIZATION OF A KAOLIN-RICH CEMENT PRECURSOR OF A CONCRETE FOR DISPOSAL OF LOW-LEVEL RADIOACTIVE WASTE
Yasmina Mouheb, Nour-El-Hayet Kamel*, Soumia Kamariz, Fairouz Aouchiche and Dalila Moudir
ABSTRACT
Concrete is a second containment barrier for low-level radioactive elements. Cement-based materials are widely used in the nuclear industry for the packaging and storage of radioactive waste. Actually, innovative concretes contain cements with both Si2O5 and Si2O6 units in aluminosilicates. In this study, kaolin-enriched cement is synthesized from sand, gravel, Ca2SiO4 and Ca3Al2O5. It is calcined at 1450?C for 2 h. Its structure is identified before incorporation into the concrete. The characterization of this cement is carried out by different methods of analysis XRD, FTIR, SEM. The X-ray diffraction analysis shows that this cement is mainly constituted by 90% XAlSi3O8 alkaline aluminosilicates (X can be K, Li or Na), with Si2O6 units. The Fourier Transform Infrared spectroscopy shows the main bonds vibrations of KAlSi3O8 and those of feldspars, such as the asymmetrical elongation vibrations of (Si?O?Si) and (Si?O?Al(Si)), the deformation absorption of (O?Si(Al)?O) and (O?Si?O). The shoulder between 1000 and 1200 cm-l is associated to the stretching of Si(Al)-O tetrahedrons. These bands overlap with those of LiAlSi4O10 petalite, a secondary aluminosilicate phase in the cement, which contains Si2O5 units. The Scanning electron microscopy micrographs show the cement morphology. The aim of synthesizing cement with Si2O5 and Si2O6 units is reached.
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