Lanthanum-Neodymium-Co-Substituted Calcium Fluorobritholites
Lanthanum-Neodymium-Co-Substituted Calcium Fluorobritholites作者机构：Higher Institute of Applied Sciences and Technology of Gabes Gabes University Gabes Tunisia RU Catalysis and Materials for Environment and Process Engineering School Gabes University Gabes Tunisia Chemistry Department Faculty of Sciences Yanbu Taibah University Yanbu Al Bahr KSA
出 版 物：《Journal of Materials Science and Chemical Engineering》 (材料科学与化学工程（英文）)
年 卷 期：2018年第6卷第7期
页 面：151-162页
主 题：Calcium Fluorobritholites Lanthanum-Neodymium Ionic Substitutions
摘 要：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 Ca8La2-xNdx(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 (VIrLa3+= 1.032A, VIrNd3+= 0.983A), their mutual substitutions led to solid solutions in whole range of composition with preferential occupation of Me (2) sites.
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