Publications Scientifiques

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Author: search.filters.author.Moudir, D.

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    Effect of the iron concentration on the properties of an aluminosilicate glass used for storage of radioactive waste
    (PARLAR SCIENTIFIC PUBLICATIONS (PSP), 2016) Moudir, D.; Ikhaddalene, Soumia; Kamel, N.; Benmounah, A.; Zibouche, Fatima; Mouheb, Y.; Aouchiche, F.
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    Study of the effect of Ca/Mg alkali-oxides ratio on the structure of a glass-ceramic based on an aluminosilicated glass containing 2wt.% of zirconolite crystalline phase
    (2014) Souag, Rafika; Kamel, N.; Mouheb, Y.; Hammadi, M.; Kamel, Z.; Moudir, D.; Aouchich, F.; Kamariz, S.
    New nuclear glass-ceramics are extensively studied for the radioactive waste confinement, due to the double confinement conferred by the glass-ceramics. In this study, a glass-ceramic constituted by an aluminosilicate glass in the system: SiO2-Al2O3-CaO-MgOZrO2-TiO2, containing 2wt.% of Ca0.83Ce0.17ZrTi1.66Al0.34O7 zirconolite, has been synthesized by the discontinuous method. Cerium, an actinide surrogate is introduced both in the glass and ceramic phases. The synthesis is performed by a double melting at 1350 °C, followed by a nucleation at 564°C, during 2 h, and a crystal growth at 1010°C during 3 h. Then effect of Ca / Mg ratio on the distribution of the crystalline network in the material was studied for Ca / Mg ratios ranging from 0.4 to 5.5. For the whole of the materials, Archimedes density is about 2.80 g/cm3 . X-ray diffraction (XRD) analysis shows that the increase of Ca/Mg ratio leads to the increase of aluminosilicated crystalline phases with high Ca contents; the materials molar volumes remaining constant. The zirconolite phase is not affected by these additive aluminosilicated phases. The scanning electron microscopy analysis (SEM) coupled with energy dispersive X-ray (EDX) analysis confirmed these results; and shows the uniformity of distribution of the ceramics in the bulk of the materials
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    Study of leaching of a 2M-Zirconolite (Ca0,83Ce0,17ZrTi1,66Al0.34O7) in acidic and basic media
    (2015) Souag, Rafika; Kamel, N.; Hammadi, M.; Kamel, Z.; Moudir, D.; Aouchich, F.; Kamariz, S.
    Zirconolite is a mineral intended for actinides elements confinement and is known for its good chemical durability. In this work, 2M-zirconolite, with the chemical formula: Ca0,83Ce0,17ZrTi1,66Al0.34O7 have been synthesized at 1400 o C by the metallurgical route at a laboratory scale. This stoechiometry corresponds to a CeO2 loading of 8.61 m.%. Ce is employed as an actinide surrogate. The effect of both pH and temperature on the chemical durability of this mineral has been studied. Phase identification and micrography observations have been done by X-ray diffraction, scanning electronic microscopy, and Fourrier transform infra-red spectroscopy. The end-product has a monophasic structure of 2M-zirconolite. Its density is about 4.013 g/cm3 , and its relative density is of 96 %TD. It has a microhardeness of 370 MPa. The Ce behavior in leaching media of extreme pH values: acidic medium (pH = 2) and basic medium (pH = 12), at 23 o C and 70 o C, shows that the Ce dissolution speeds are faster at 70 o C compared with those obtained at 23 o C. The 2M-zirconolite matrice presently studied appears to have a good chemical durability
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    Effect of the ce content on a nuclear waste glassy matrix in the system SiO2-Al2O3-CaO-MgO-ZrO2-TiO2, synthesized at a low melting temperature
    (DAVID PUBLISHING, 2013) Nour-el-Hayet, Kamel; Moudir, D.; Ziane, K.; Djerridi, A.; Mouhamou, S.; Benmounah, A.; Souag, Rafika; Taouinet, M.; Ait-Amar, H.
    Aluminosilicated glasses containing Zr and Ti metals have satisfactory properties, and may be suitable as nuclear glasses, dedicated for storage of radioactive waste solutions. This study summarizes the synthesis of a glassy matrix in the system: SiO2-Al2O3-CaO-MgO-ZrO2-TiO2. Ce element was added as an actinide surrogate. The effect of Ce addition on the glass structure is investigated, for Ce contents ranging between 0 and 15 wt.%. For the whole of glasses, a double melting at 1,350°C during 5 h gave monophasic homogeneous glasses. Both X-ray diffraction and scanning electron microscopy analyses reveal a pure amorphous structure. Most of the basic properties increase with the glass Ce content, the Archimedes density from 2.827 to 3.049 g/cm3, and Vickers indentations from 680 to 862 HV. Oxygen molar volumes are not affected by the glasses Ce contents. The differential thermal analysis show that the glass transformation temperature decreases with the Ce content, and with the heavy elements content. The optical absorption spectroscopy study shows that the Nd cations environment is not altered by the glasses Ce concentration. A preliminary corrosion test leads to low dissolutions of Si, Ca and Zr, estimated by ICP analyses to few ppms. Out coming investigations are in course for further glasses network characterizations