Author(s)

Mustapha Hidouri^1,2, Nawaf Albeladi³

¹Higher Institute of Applied Sciences and Technology of Gabes, Gabes University, Gabes, Tunisia.
²RU Catalysis and Materials for Environment and Process, Engineering School, Gabes University, Gabes, Tunisia.
³Chemistry Department, Faculty of Sciences Yanbu, Taibah University, Yanbu Al Bahr, KSA.

Britholites are considered as potential matrices for storage of nuclear wastes such as minor actinides and long-lived fission byproducts. This investigation is concerned with the study of simultaneous substitution in calcium fluor-britholite framework of two lanthanide ions assimilated to radionuclides. A series of calcium fluorbritholites doped with lanthanum and neodymium Ca₈La_2-xNd_x(PO₄)₄(SiO₄)₂F₂ with 0 ≤ x ≤ 2 were prepared via a solid state reaction in the temperature range 1450℃- 1250℃. The obtained products were characterized by several techniques such as Chemical analysis via Inductively coupled plasma Atomic emission spectrometry ICP-AES, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy FTIR and Nuclear magnetic resonance ³¹P NMR (MAS). Obtained solid solutions containing lanthanum and neodymium in variable proportions were typically apatite of hexagonal structure P63/m spatial group. The stoichiometry of the powders was verified via the metal/(phosphate + silicate) molar ratios found at about 1.67. The lattice parameters a and c calculated by the Rietveld method decreased as neodymium level increased. Despite, the close respective sizes of lanthanum and neodymium ions (^VIr_La3+= 1.032A, ^VIr_Nd3+= 0.983A), their mutual substitutions led to solid solutions in whole range of composition with preferential occupation of Me (2) sites.

Calcium Fluorobritholites, Lanthanum-Neodymium, Ionic Substitutions

Hidouri, M. and Albeladi, N. (2018) Lanthanum-Neodymium-Co-Substituted Calcium Fluorobritholites. Journal of Materials Science and Chemical Engineering, 6, 151-162. doi: 10.4236/msce.2018.67016.