Calcium thorium phosphate (Whitlockite-type mineral). Synthesis and structure refinement

Орлова, А. И.; Khainakov, Sergei A.; Loginova, E. E.; Oleneva, T. A.; Granda, Santiago García; Kurazhkovskaya, V. S.

doi:10.1134/s1063774509040087

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…Considering that ions of other metals (e.g., rare‐earth elements and actinides) can be incorporated into the structure of TCP, the latter is a promising matrix for immobilizing radioactive wastes from nuclear power plants, and an optically active material …”

Section: Introductionmentioning

confidence: 99%

“…3,4 Considering that ions of other metals (e.g., rare-earth elements and actinides) can be incorporated into the structure of TCP, the latter is a promising matrix for immobilizing radioactive wastes from nuclear power plants, and an optically active material. [5][6][7][8][9] Three thermodynamically stable polymorphs of TCP are known. The low-temperature b form has a trigonal structure with unit cell parameters: a = b = 10.4352(2) Å , c = 37.4029 (5) Å (the hexagonal setting).…”

Section: Introductionmentioning

confidence: 99%

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Phase Relationships in the Tricalcium Phosphate—Cerium Phosphate System. Thermal behavior of Phases Present in the System

Matraszek

Szczygieł

2012

J. Am. Ceram. Soc.

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A diagram representing the phase relationships in the Ca3(PO4)2–CePO4 phosphate system has been developed on the basis of results obtained using thermal analysis (DTA/DSC/TG), X‐ray diffraction (XRD), and scanning electron microscopy (SEM/EDS) methods. One intermediate compound with formula Ca3Ce(PO4)3 occurs in the Ca3(PO4)2–CePO4 system at temperature exceeding 1275°C. The compound melts at 1833°C and has one structural form. In the system a solid solution, having the structure of low‐temperature form of calcium phosphate Ca3−3xCex(PO4)2−x (where x is a molar fraction of CePO4), exists. The temperature and concentration range of the solid solution has been determined. It has been shown that the Ca9Ce(PO4)7 phase should be understood as a limited solid solution with x = 0.25.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phase Relationships in the Tricalcium Phosphate—Cerium Phosphate System. Thermal behavior of Phases Present in the System

Matraszek

Szczygieł

2012

J. Am. Ceram. Soc.

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“…Many of the compounds listed here have been studied and continue to be actively investigated by researchers led by the co-author of this work (Prof Orlova), including those with structures of garnet [185,189,190,191,192,193,194], P-pollucite [205,206,207,208,209,210,211,212,213,214,215], pollucite [214,215,293], monazite [141,352], sodium zirconium phosphate (NZP) [21,209,383,384,388,392,393,394,396,405,407,408,409,412,413,414,415,416,417,418,419], langbeinite [416,417,418,419], whitlockite [87,89,424,425,426,427,428,429,430] and scheelite [89,445,446]. Overall crystalline ceramics are characterized as much more durable compared with glasses of the same chemical compo...…”

Section: Summary Of Crystalline Ceramic Waste-formsmentioning

confidence: 99%

Ceramic Mineral Waste-Forms for Nuclear Waste Immobilization

2019

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Crystalline ceramics are intensively investigated as effective materials in various nuclear energy applications, such as inert matrix and accident tolerant fuels and nuclear waste immobilization. This paper presents an analysis of the current status of work in this field of material sciences. We have considered inorganic materials characterized by different structures, including simple oxides with fluorite structure, complex oxides (pyrochlore, murataite, zirconolite, perovskite, hollandite, garnet, crichtonite, freudenbergite, and P-pollucite), simple silicates (zircon/thorite/coffinite, titanite (sphen), britholite), framework silicates (zeolite, pollucite, nepheline /leucite, sodalite, cancrinite, micas structures), phosphates (monazite, xenotime, apatite, kosnarite (NZP), langbeinite, thorium phosphate diphosphate, struvite, meta-ankoleite), and aluminates with a magnetoplumbite structure. These materials can contain in their composition various cations in different combinations and ratios: Li–Cs, Tl, Ag, Be–Ba, Pb, Mn, Co, Ni, Cu, Cd, B, Al, Fe, Ga, Sc, Cr, V, Sb, Nb, Ta, La, Ce, rare-earth elements (REEs), Si, Ti, Zr, Hf, Sn, Bi, Nb, Th, U, Np, Pu, Am and Cm. They can be prepared in the form of powders, including nano-powders, as well as in form of monolith (bulk) ceramics. To produce ceramics, cold pressing and sintering (frittage), hot pressing, hot isostatic pressing and spark plasma sintering (SPS) can be used. The SPS method is now considered as one of most promising in applications with actual radioactive substances, enabling a densification of up to 98–99.9% to be achieved in a few minutes. Characteristics of the structures obtained (e.g., syngony, unit cell parameters, drawings) are described based upon an analysis of 462 publications.

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“…XRD spectrum Figure 2(a), Figure 2(b), shows that Thorium (V) sulfide and Thorium are minor and trace elements in sample 1 respectively. Table 3 is a review of the chemical composition of each mineral and its description which reflects the condition of its formation [13]. Table 4 represents the concentrations in Bq/kg of the different radionuclides in the samples.…”

Section: Xrd Analysismentioning

confidence: 99%

A Comparison Study of Soil Samples from Sinai Province in Egypt by Using X-Ray Diffraction and Gamma-Ray Analysis

Baz

2015

WJNST

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Ten soil samples from Jabal Al Qur, Wadi Baba, and Wadi Sieh in Sinai, Egypt, were analyzed by XRD spectroscopy. The XRD spectroscopy results indicate that the major, minor and trace constituents varied from one sample to another. Samples were also analyzed by HPGe gamma spectrometer to determine the activity concentration of U-238, Th-232 series and K-40. The concentrations for 238 U ranged from 57.03 to 4220.41 Bq/kg with an average 1110.75 Bq/kg, for 232 Th, ranged from 13.55 to130.46 Bq/kg with an average 71.85 Bq/Kg. The concentrations for 40 K were in the range from 12.18 to 948.93 Bq/kg with an average value 457.09 Bq/kg. The average activity concentration values of 226 Ra, 232 Th, and 40 K, in all the collected samples were higher than the world average. The radium equivalent (Req), absorbed dose rate (DR), the effective dose rate (Deff), and hazard indices resulted due to the natural radionuclides in soil are also calculated. The Results show that the study area is not safe for human and environments.

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Calcium thorium phosphate (Whitlockite-type mineral). Synthesis and structure refinement

Cited by 10 publications

References 17 publications

Phase Relationships in the Tricalcium Phosphate—Cerium Phosphate System. Thermal behavior of Phases Present in the System

Phase Relationships in the Tricalcium Phosphate—Cerium Phosphate System. Thermal behavior of Phases Present in the System

Ceramic Mineral Waste-Forms for Nuclear Waste Immobilization

A Comparison Study of Soil Samples from Sinai Province in Egypt by Using X-Ray Diffraction and Gamma-Ray Analysis

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