Development of Zirconolite-based Glass-Ceramics for the Conditioning of Actinides

2000 ◽  
Vol 663 ◽  
Author(s):  
P. Loiseau ◽  
D. Caurant ◽  
N. Baffier ◽  
L. Mazerolles ◽  
C. Fillet
Keyword(s):  
Glass Composition ◽  
Heating Temperature ◽  
Glass Ceramics ◽  
Minor Actinides ◽  
Extended Defects ◽  
Residual Glass ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Aluminosilicate ◽  
High Level

ABSTRACTZirconolite (CaZrTi2O7) based glass-ceramics designed for the specific immobilization of plutonium wastes or minor actinides (Np, Am, Cm) from high level radioactive wastes were investigated. To reach an efficient double containment, actinides must be preferentially located in the crystalline phase, which is homogeneously dispersed in a calcium aluminosilicate residual glass. Several heat treatments (between 950° and 1350°C) of a parent glass belonging to the SiO2-Al2O3-CaO system and containing TiO2 and ZrO2 were performed to prepare glass-ceramics. Trivalent minor actinides were simulated introducing Nd2O3 in the glass composition. Electron microscopy, X-ray diffraction (XRD) and thermal analysis have shown that devitrification processes in the bulk and on glass surface are different. They lead to the crystallization of zirconolite in the bulk and to a mixture of titanite (CaTiSiO5) and anorthite (CaAl2Si2O8) near the surface. For heat treatment temperatures greater than or equal to 1250°C, baddeleyite (m-ZrO2) crystals form at the expense of zirconolite in the bulk of glass-ceramics. XRD indicates that the order in zirconolite Ca/Zr planes increases with heating temperature. At the same time, extended defects density decreases.

scholarly journals Bone bonding ability of some borate bio-glasses and their corresponding glass-ceramic derivatives

2012 ◽  
Vol 6 (4) ◽  
pp. 183-192 ◽  
Author(s):  
Fatma Margha ◽  
Amr Abdelghany
Keyword(s):  
Heat Treatment ◽  
Fourier Transform ◽  
Glass Ceramic ◽  
Glass Composition ◽  
Glass Ceramics ◽  
Soda Lime ◽  
Phosphate Solution ◽  
Borate Glasses ◽  
X Ray Diffraction ◽  
X Ray

Ternary borate glasses from the system Na2O?CaO?B2O3 together with soda-lime-borate samples containing 5 wt.% of MgO, Al2O3, SiO2 or P2O5 were prepared. The obtained glasses were converted to their glass-ceramic derivatives by controlled heat treatment. X-ray diffraction was employed to investigate the separated crys?talline phases in glass-ceramics after heat treatment of the glassy samples. The glasses and corresponding glass-ceramics after immersion in water or diluted phosphate solution for extended times were characterized by the grain method (adopted by several authors and recommended by ASTM) and Fourier-transform infrared spectra to justify the formation of hydroxyapatite as an indication of the bone bonding ability. The influence of glass composition on bioactivity potential was discussed too.

Zirconolite-based glass-ceramics for actinides immobilization: Effects of glass composition and of actinides simulant nature

2002 ◽  
Vol 757 ◽  
Author(s):  
Pascal Loiseau ◽  
Daniel Caurant ◽  
Isabelle Bardez ◽  
Odile Majerus ◽  
Noël Baffier ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Field Strength ◽  
Glass Composition ◽  
Glass Ceramics ◽  
Glassy Matrix ◽  
Minor Actinides ◽  
Volume Percentage ◽  
Parent Glass ◽  
Calcium Aluminosilicate ◽  
Molar Substitution

ABSTRACTZirconolite (CaZrTi2O7) based glass-ceramics, in which the crystalline phase (aimed at preferentially incorporating minor actinides or Pu) is embedded in a durable calcium aluminosilicate glassy matrix, can be envisaged as good waste form candidates. In this study, the effect of parent glass composition – and particularly of TiO2, ZrO2, CaO and Al2O3 amounts -on the microstructure and the structure of the glass-ceramics obtained after controlled devitrification (nucleation + crystal growth) is reported. It clearly appears that the volume percentage of zirconolite crystals and their nucleation rate in the bulk of the glass strongly depends both on (CaO + ZrO2 + TiO2) and Al2O3 amounts in parent glass. Neodymium is mainly used to simulate trivalent minor actinides whereas several samples were also prepared with other lanthanides (Ce, Eu, Gd, Yb) in order to investigate the effect of simulant field strength in glass on the nature and the composition of the crystals formed. The effect of partial or total molar substitution of ZrO2 by HfO2 in parent glass composition was also studied in order to prepare Ca(Zr1-xHfx)Ti2O7 (0 < × ≤ 1) based glass-ceramics which could be interesting in order to minimize criticality problems.

Fabrication of 239/238Pu-Zirconolite Ceramic Pellets by Natural Sintering

2003 ◽  
Vol 807 ◽  
Author(s):  
T. Advocat ◽  
F. Jorion ◽  
T. Marcillat ◽  
G. Leturcq ◽  
X. Deschanels ◽  
...  
Keyword(s):  
Grain Size ◽  
Radioactive Waste ◽  
Nuclear Waste ◽  
Chemical Stability ◽  
Minor Actinides ◽  
Loading Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Physical And Chemical ◽  
Inorganic Matrix

ABSTRACTZirconolite is a potential inorganic matrix that is currently investigated in France, in the framework of the 1991 radioactive waste management law, with a view to provide durable containment of the trivalent and tetravalent minor actinides like neptunium, curium, americium and small quantities of unrecyclable plutonium separated from other nuclear waste. To confirm the actinide loading capacity of the zirconolite calcium site and to study the physical and chemical stability of this type of ceramic when subjected to alpha self-irradiation, zirconolite ceramic pellets were fabricated with 10 wt% plutonium oxide (isotope 239 or 238). The 55 pellets are dense (> 93.3% of the theoretical density on average) and free of cracks. They are characterized by a grain size of between 10 and 20 micrometers. X-ray diffraction analyses confirmed the presence of the zirconolite 2M crystalline structure.

In Situ X-Ray Diffraction Studies of Crystallization Growth Behavior in ZnO-Bi2O3-B2O3 Glass as a Route to Functional Optical Devices

MRS Advances ◽  
2018 ◽  
Vol 3 (11) ◽  
pp. 563-567 ◽  
Author(s):  
Quentin Altemose ◽  
Katrina Raichle ◽  
Brittani Schnable ◽  
Casey Schwarz ◽  
Myungkoo Kang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Xrd ◽  
Dsc Measurements ◽  
Transmission Window

ABSTRACTTransparent optical ZnO–Bi2O3–B2O3 (ZBB) glass-ceramics were created by the melt quenching technique. In this work, a melt of the glass containing stoichiometric ratios of Zn/Bi/B and As was studied. Differential scanning calorimeter (DSC) measurements was used to measure the thermal behavior. VIS/NIR transmission measurements were used to determine the transmission window. X-ray diffraction (XRD) was used to determine crystal phase. In this study, we explore new techniques and report a detailed study of in-situ XRD of the ZBB composition in order to correlate nucleation temperature, heat treatment temperature, and heat treatment duration with induced crystal phase.

Structure Characterization of Sintered CaO-Al2O3-SiO2 Glass-Ceramic Reinforced with Spodumene

2013 ◽  
Vol 834-836 ◽  
pp. 309-314
Author(s):  
Zi Fan Xiao ◽  
Jin Shu Cheng ◽  
Jun Xie
Keyword(s):  
Glass Ceramic ◽  
Energy Dispersive Spectrometry ◽  
Crystal Size ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Structure Characterization ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray

A glass-ceramic belonging to the CaO-Al2O3-SiO2(CAS) system with different composition of spodumene and doping the Li2O with amount between 0~2.5 % (mass fraction) were prepared by onestage heat treatment, under sintering and crystallization temperature at 1120 °C for two hours. In this paper, differential thermal analysis, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and bending strength test were employed to investigate the microstructure and properties of all samples. β-wollastonite crystals were identified as the major crystalline phases, and increasing Li2O was found to be benefit for the crystallization and tiny crystalline phases remelting, resulting in the content of major crystalline phases increased first and then decreased with increasing the expense of spodumene. Meanwhile, the crystal size can be positively related with the content of Li2O. The preferable admixed dosage of spodumene can be obtained, besides the strength of glass-ceramics can be more than 90 MPa.

Formation of Tricalcium Silicate Prepared by Electric and Microwave Sintering

2010 ◽  
Vol 148-149 ◽  
pp. 1119-1123
Author(s):  
Kai Ke ◽  
Bao Guo Ma ◽  
Xiao Liang Wang ◽  
Xiang Guo Li
Keyword(s):  
Heating Temperature ◽  
Microwave Sintering ◽  
Electric Heating ◽  
Tricalcium Silicate ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Sintering ◽  
Sintering Method

A microwave sintering method was used to prepare C3S from Ca(OH)2, SiO2 and MexOy. f-CaO assay, X-ray diffraction and SEM were used to characterize the sintered samples.The results indicated that ion oxides played a very important role in C3S formation in conventional sintering, the use of MexOy as an additive was so effective in promoting C3S formation. The experimental results showed that samples were heated at an electric heating temperature(1500°C) and then further sintered with microwave for 30~60 min, tricalcium silicate could be formed with kilogram step. The new burning technique can greatly increase the forming speed of tricalcium silicate, MnO2, CuO and Ni2O3 could enhance the microwave sintering.

The Effects of Preparation Conditions And Chemical Composition On CMAS Glass Ceramics With One Step Process

2021 ◽  
Author(s):  
Yuliang Guo ◽  
Huixin Jin ◽  
Yuandan Xiao ◽  
Huahao Song ◽  
Shangjiefu Wang
Keyword(s):  
Solid Waste ◽  
Theoretical Basis ◽  
Chromium Content ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Crystallization Activation Energy ◽  
X Ray ◽  
Preparation Conditions ◽  
Treatment Conditions ◽  
One Step

Abstract Based on the composition of Cr-doped solid waste, other oxides were added to adjust the composition to prepare glass-ceramics with on step composition, and the effect of heat treatment system (including temperature and holding time), chromium content, MnO and Fe2O3 doped on the crystallization and physical properties of glass-ceramics was studied. The samples were characterized by X-ray diffraction, differential thermal analysis and scanning electron microscopy. The results show that the best treatment conditions are 1090 ℃ for 4h, and the amount of dissolved chromium reaches 5%. The main crystallization phase is diopside and anorthite. The hardness and chemical stability of the material were measured. The doping of MnO and Fe2O3 increases the crystallization activation energy of glass ceramics, and makes the crystal phase more uniform as the SEM results. This experiment provides a theoretical basis for the preparation of CMAS glass ceramics from chromium containing solid waste.

scholarly journals Shape Tuning of Magnetite Nanoparticles Obtained by Hydrothermal Synthesis: Effect of Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Nayely Torres-Gómez ◽  
Osvaldo Nava ◽  
Liliana Argueta-Figueroa ◽  
René García-Contreras ◽  
Armando Baeza-Barrera ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Nanoparticle Synthesis ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Pure Phase ◽  
High Level ◽  
Shape Tuning ◽  
Magnetite Phase

In this work, we present a simple and efficient method for pure phase magnetite (Fe3O4) nanoparticle synthesis. The phase structure, particle shape, and size of the samples were characterized by Raman spectroscopy (Rm), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDS), and transmission electron microscopy (TEM). The morphology tuning was controlled by the temperature of the reaction; the nanoparticles were synthesized via the hydrothermal method at 120°C, 140°C, and 160°C, respectively. The Rm and XRD spectra showed that all the nanoparticles were Fe3O4 in a pure magnetite phase. The obtained nanoparticles exhibited a high level of crystallinity with uniform morphology at each temperature, as can be observed through TEM and SEM. These magnetic nanoparticles exhibited good saturation magnetization and the resulting shapes were quasi-spheres, octahedrons, and cubes. The samples showed striking magnetic properties, which were examined by a vibrating sample magnetometer (VSM). It has been possible to obtain a good morphological control of nanostructured magnetite in a simple, economical, and scalable method by adjusting the temperature, without the modification of any other synthesis parameter.

scholarly journals Five-fold twinned β-PbF2 nanocrystals in oxyfluoride glass ceramics

RSC Advances ◽  
2018 ◽  
Vol 8 (71) ◽  
pp. 40787-40793 ◽  
Author(s):  
Yuao Guo ◽  
Lijuan Zhao ◽  
Yuting Fu ◽  
Pan Dong ◽  
Liying Guo ◽  
...  
Keyword(s):  
Glass Ceramics ◽  
Lanthanide Ions ◽  
X Ray Diffraction ◽  
Oxyfluoride Glass ◽  
X Ray ◽  
Trivalent Lanthanide ◽  
Quenching Method

Oxyfluoride glass ceramics (GCs) doped with trivalent lanthanide ions (Ln3+) have been prepared using a conventional melting–quenching method and studied by X-ray diffraction (XRD).

Effects of Glass Elements on the Structural Evolution ofin situGrown Ferroelectric Perovskite Crystals in Sol-gel Derived Glass-ceramics

1997 ◽  
Vol 12 (4) ◽  
pp. 1131-1140 ◽  
Author(s):  
Kui Yao ◽  
Weiguang Zhu ◽  
Liangying Zhang ◽  
Xi Yao
Keyword(s):  
Crystallization Process ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Structural Evolution ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Process Change ◽  
X Ray ◽  
Ferroelectric Perovskite

Several ABO3perovskite ferroelectric crystals, PbTiO3, Pb(Zr, Ti)O3, and BaTiO3have beenin situgrown from amorphous gels with glass elements, and the structural evolution has been systematically investigated using x-ray diffraction (XRD), infrared spectra (IR), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and dielectric measurements. It is found that in the Si-contained glass-ceramic systems, Si and B glass elements are incorporated into the crystalline structures, resulting in the variation of the crystallization process, change of lattice constant, and dielectric properties. Some metastable phases expressed by a general formula AxByGzOw(A = Pb and Ba; B = Zr and Ti; G for glass elements, especially for Si) have been observed and discussed.

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