Study of Chromium-Lead-Phosphate Glasses by XRD, IR, Density and Chemical Durability - Advances in Materials Physics and Chemistry

AMPC > Vol.8 No.6, June 2018

Study of Chromium-Lead-Phosphate Glasses by XRD, IR, Density and Chemical Durability ()

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DOI: 10.4236/ampc.2018.86018 1,007 Downloads 2,555 Views Citations

Author(s)

Radouan Makhlouk¹, Nadia Beloued¹, Said Aqdim^1,2*

Affiliation(s)

¹Laboratory of Materials Engineering for Environment and Valorization, Faculty of Sciences, Hassan II University Ain Chock, Casablanca, Morocco.
²Mineral Chemistry Laboratory, Department of Chemistry, Faculty of Science, Hassan II University Ain Chock, Casablanca, Morocco.

ABSTRACT

Glasses in the ternary system Cr₂O₃-PbO-P₂O₅ were prepared by direct melting of the mixture with stoichiometric proportions of the reagents Cr₂O₃, PbO and (NH₄)₂HPO₄ at 1080℃. The glasses obtained are transparent in colour and have a non-hygroscopic appearance. The study of the dissolution rate was carried out on ternary glasses xCr₂O₃-(45-x)PbO-55P₂O₅ with (1 ≤ x ≤ 4; mol%), immersed in distilled water at 90℃ for 24 days, indicating a maximum of chemical durability when the level of chromium oxide passed through 2 mol%. Both, IR spectra and X-ray diffraction have indicated the predominance of metaphosphate or cyclic metaphosphate groups with some traces of isolated orthophosphate groups when the Cr₂O₃ content is equal to x = 2. Analysis of the density values also, has showed a maximum density for x = 2 mol%. The covalent radius values of oxygen have indicated that the minimum value rcal (O^2–) is observed for x = 2 mol% and therefore a relatively high reinforcement of the metal-oxygen-phosphorus (Cr-O-P) bonds. SEM Micrographs have exhibited two phases, a vitreous phase and a crystalline phase. The radical change in the structure from ultraphosphate Q³ groups to ring metaphosphate Q² and orthophosphate groups Q⁰ seems to be the cause of the formation of crystallites. Beyond 2 mol% of Cr₂O₃, the structure of the glass changed relatively and the orthophosphate phases increased to the detriment of the metaphosphate phases. We observed a decrease in chemical durability. However, it was confirmed that the dissolution rate (D_R) of the S₂ analysed compound is comparable to the values of borosilicate glasses which are used as alternative materials for the immobilisation of nuclear waste substances.

KEYWORDS

Chemical Durability, Phosphate Glasses, Chromium Oxide, IR, XRD, SEM, Nu-clear and Chemical Wastes

Share and Cite:

Makhlouk, R. , Beloued, N. and Aqdim, S. (2018) Study of Chromium-Lead-Phosphate Glasses by XRD, IR, Density and Chemical Durability. Advances in Materials Physics and Chemistry, 8, 269-280. doi: 10.4236/ampc.2018.86018.

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