Browsing by Author "Moudir, Dalila"

Filter results by typing the first few letters
Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    Effect of crystallization time on the structure of the Aluminosilicate glass-ceramic
    (IOP Publishing Ltd, 2018) Souag, Rafika; Nidal, Kamel; Moudir, Dalila; Mouheb, Yasmina; Kamariz, S.
    All This study deals with the influence of the time of crystallization on the structure of an aluminosilicate glass-ceramic ceramized by a nucleation –crystallization treatment at 790°C for 2 h, and 900°C, for different periods of time ranging from 2 to 12 h. For the whole of the materials, Archimedes density is between 2441-2578 kg/m3. Both X-ray diffraction and scanning electron microscopy analyses reveal two main crystalline phases for the whole of the heating treatments, namely spodumen and leucite. These phases grow regularly with the crystallization time. In addition, aqueous stability testing was carried out using the standard MCC-2 static leach test method at 90 °C and V(ml) = 30 S(cm2) for a series of five test durations - 7, 14, 28, 35 and 42 days. The X-ray fluorescence analytical technique was used to determine the concentration of lanthanum (La) and molybdenum (Mo) leached in our material. The dissolution parameters, in this case the normalized elemental mass loss (NL) and the leaching rate (τ) of each element, were determined from these concentrations. The results demonstrate that The leaching tests showed that the material is stable and it stabilizes at low values (2.5 10−9Kg/m2) for La when the ceramization time does not exceed 4h beyond this, Leaching equilibrium and the passivation phase is broken. For Mo and for all glass ceramics at different times of crystallization, the equilibrium reaches (3.15 10-8 Kg/m2j) and the passivation layer is formed. The glass ceramics at different time of cristallization presently studied appears to have a good chemical durability.
  • No Thumbnail Available
    Item
    Optimisation des conditions de synthèse d'une vitrocéramique nucléaire, contenant une phase cristalline riche en zirconium, obtenue à partir d'un verre de base aluminosilicate de type SiO2-Al2O3-CaO-MgO- ZrO2
    (2014) Moudir, Dalila
    Les vitrocéramiques, matériaux de confinement des déchets radioactifs, contiennent des cristaux, qui peuvent renfermer des radioisotopes toxiques. Ces matériaux constituent donc une double protection, dans le confinement de la radioactivité. Dans cette étude, une vitrocéramique riche en cristaux contenant du zirconium (Zr) sera synthétisée par la méthode discontinue de fusion à 1350°C et céramisation. Les oxydes de zirconium ont une affinité pour certains radioisotopes toxiques, tels que les actinides et produits de fission. Le verre de base du matériau est un aluminosilicate riche en Zr. Les lanthanides comme le cérium et le néodyme sont utilisés comme simulateurs des radioisotopes. Les conditions de synthèse de la vitrocéramique seront optimisées, pour différentes teneurs en ZrO2 dans le matériau. Les vitrocéramiques obtenues seront caractérisées par leurs propriétés physiques et microstructurales, au moyen de différentes techniques spectroscopiques afin de déterminer la meilleure vitrocéramique dopée au zirconium
  • No Thumbnail Available
    Item
    Study of the influence of Na/Li on the microstructure of an aluminosilicate nuclear glass
    (2018) Moudir, Dalila; kamel, Nour El Hayet; Benmounah, Abdelbaki; Ikhaddalene, Soumia; Mouheb, Yasmina; Aouchiche, Fairouz
  • No Thumbnail Available
    Item
    TiO2 addition into nuclear glass ceramic : study of the crystalline phases, structure and chemical durability
    (Hanyang University, 2022) Souag, Rafika; Kamel, Nour Elhayet; Moudir, Dalila; Mouheb, Yasmina; Aouchiche, Fayrouz
    This paper studies the nuclear glass ceramic based on aluminosilicate glass. It is proposed the addition of TiO2 on the crystalline phase. The structure and chemical durability have been investigated. The materials with four TiO2 contents, ranging from 4.11 to 7.11 wt.%, are synthesized by a discontinuous method. The 7.11 wt.% TiO2 glass ceramic synthesis was not successful and crystallizes during the melting stage. For the others materials, Archimedes density ranges between 2.891 and 2.962 g/cm3. For the majority of materials, X-ray diffraction analysis allows the identification of an aluminosilicate that belongs to pyroxenes silicates family as the initial phase, powelite and calzirtite. These phases are known as radionuclides’ sequestration minerals. Both SEM and DTA analyses confirm these findings. The FTIR analysis of materials reveals the complex glass-ceramics chemical composition. MCC1 and MCC2 tests, performed on selected glass ceramic materials, indicate that the materials containing 4.11 and 5.11 wt.% TiO2 are the most durable against Si, Al, Mg and Ce elements release, in MCC2 test; the Ce (minor actinide surrogate) leaching rate being negligible (193.7☓10-9 kg/m2d after 28 leaching days for 5.11 wt.% of TiO2 content). These results make valuable conclusions for the selection of the glass ceramic suitable to the high-level waste disposal