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Immobilization of “Mo 6+ ” in Monazite Lattice: Synthesis and Characterization of New Phosphomolybdates, La 1−x Ca x P 1−y Mo y O 4 , Where x=y=0.1–0.9
Author(s) -
Pratheep Kumar Sathasivam,
Gopal Buvaneswari
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.04183.x
Subject(s) - monazite , actinide , solid solution , lanthanide , materials science , powder diffraction , nuclide , nuclear chemistry , scheelite , mineralogy , crystallography , chemistry , inorganic chemistry , metallurgy , tungsten , zircon , geology , ion , paleontology , organic chemistry , physics , quantum mechanics
In the process of high‐level nuclear waste (HLW) disposal, monazite, LaPO 4 is considered as one of the potential phosphate ceramics to immobilize lanthanides and actinides. HLW along with hazardous long‐lived nuclides contains elements such as Zr, Mo, etc. in higher wt%. In the current investigation, an attempt was made to introduce “Mo” into the monazite lattice. The phosphomolybdates of the formula La 1− x Ca x P 1− y Mo y O 4 , x, y =0.1–0.9 were synthesized by a solution route and characterized by powder X‐ray diffraction, FT‐IR, TGA/DTA, and scanning electron microscopic techniques. The phases with compositions La 0.9 Ca 0.1 P 0.9 Mo 0.1 O 4 , La 0.8 Ca 0.2 P 0.8 Mo 0.2 O 4 , and La 0.7 Ca 0.3 P 0.7 Mo 0.3 O 4 were found to be crystallized in monazite structure. The composition La 0.1 Ca 0.9 P 0.1 Mo 0.9 O 4 with X = Y =0.9 crystallized in the scheelite structure. The compositions indicate the immobilization of ∼4.1, 8.5, 12.9, and 42.5 at. wt% of “Mo.” With x, y =0.6, 0.5, 0.4, 0.3, and 0.2, along with the monazite phase, formation of a secondary phase LaP 3 O 9 was observed.