Nuclear waste immobilization into structure of zirconolite by Complex Sol Gel Process

2014 ◽  
Vol 1683 ◽  
Author(s):  
Tomasz Smoliński ◽  
Andrzej Deptuła ◽  
W. Lada ◽  
Tadeusz Olczak ◽  
Andrzej G. Chmielewski ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Nuclear Waste ◽  
Thermal Analyses ◽  
Sol Gel ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

ABSTRACTZirconolite (CaZrTi2O7) is one of the components of Synroc materials, which are regarded throughout the world nuclear as the second generation of high-level nuclear waste forms. The zirconolite phase was synthesized by a sol-gel method, with one variant of the method making use of ascorbic acid as a strong complexing agent. Into the structure of the zirconolite was incorporated 10 mol% Sr. Undoped and doped samples were examined by thermal analyses and X-ray diffraction. Addition of ascorbic acid to the sols lowered the firing temperature and promoted formation of the zirconolite phase.

Vitrification of Nuclear Wastes by Complex Sol-Gel Process

2012 ◽  
Vol 518-523 ◽  
pp. 3216-3220 ◽  
Author(s):  
Andrzej Deptula ◽  
Magdalena Milkowska ◽  
Wieslawa Lada ◽  
Tadeusz Olczak ◽  
Danuta Wawszczak ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Sol Gel ◽  
Nuclear Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silica Glasses ◽  
Sol Gel Process ◽  
High Level ◽  
Hydrolysis And Polycondensation ◽  
Nitrate Solutions

For synthesis of silica glasses designed to contain high-level nuclear wastes，a patented complex sol-gel process has been used. Surrogates of the nuclear waste elements Cs, Sr, Co, and Nd (generically denoted Me) were used. Gels in the forms of powders and sintered compacts were prepared by hydrolysis and polycondensation of tetraethoxide/Me nitrate solutions, which contained ascorbic acid as a catalyst. Transformation to final products was studied by thermogravimetric analysis, infrared spectroscopy, and X-ray diffraction. Preliminary testing of Me leaching was also completed in water. Most of the final products were porous; only a single dense form was resistant to leaching.

scholarly journals Carbonization of solid uranyl-ascorbate gel as an indirect step of uranium carbide synthesis

Nukleonika ◽  
2015 ◽  
Vol 60 (4) ◽  
pp. 921-925 ◽  
Author(s):  
Marcin Brykala ◽  
Marcin Rogowski ◽  
Tadeusz Olczak
Keyword(s):  
Ascorbic Acid ◽  
Sol Gel ◽  
Nitrogen Atmosphere ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Crucial Step ◽  
X Ray ◽  
Uranium Carbide ◽  
Vacuum Atmosphere ◽  
Sol Gel Process

Abstract The studies of the synthesis of uranium carbide from uranyl-ascorbate gels using the complex sol-gel process (CSGP) have been carried out. The synthesis of uranyl-ascorbate mixture as liquid sol from uranium trioxide and ascorbic acid and solid gel by extraction of water from sol were carefully examined. Ascorbic acid was used as a complexing agent in complex sol-gel process and as a carbon source. The crucial step to obtain final uranium carbides from the aforementioned substrates is the carbonization process. The thermal behavior of ascorbic acid and uranyl-ascorbate gels in a nitrogen atmosphere in the temperature range of 25-900°C were investigated using TG-DTG. Furthermore, the products of the carbonization of uranyl-ascorbate gels in nitrogen, argon and vacuum atmosphere were identified by X-ray diffraction. TG-DTG was used also as a method for determining of carbon residues in the samples.

Preparation of Titanium Oxide and Metal Titanates as Powders, Thin Films, and Microspheres by Novel Inorganic Sol-Gel Process

2005 ◽  
Vol 900 ◽  
Author(s):  
A. Deptuła ◽  
Kenneth C Goretta ◽  
Tadeusz Olczak ◽  
Wieslawa Lada ◽  
Andrzej G. Chmielewski ◽  
...  
Keyword(s):  
Thin Films ◽  
Ascorbic Acid ◽  
Nitric Acid ◽  
Titanium Oxide ◽  
Sol Gel ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Metal Hydroxides ◽  
X Ray ◽  
Sol Gel Process

ABSTRACTTitanium oxide and titanates based on Ba, Sr and Ca were prepared from commercial solutions of TiCl4 and HNO3. The main preparation steps for the sols consisted of elimination of chloride anions by distillation with nitric acid and addition of metal hydroxides for the titanates. Resulting sols were gelled and used to (1) prepare irregularly shaped powders by evaporation; (2) produce by a dipping technique thin films on glass, Ag, or Ti substrates; and (3) produce spherical powders (diameters <100 μm) by solvent extraction. Results of thermal and X-ray-diffraction analyses indicated that the temperatures required to form the various compounds were lower than those necessary to form the compounds by conventional solid-state reactions and comparable to those required with use of organometallic based sol-gel methods. Temperatures of formation could be further reduced by addition of ascorbic acid to the sols.

Preparation of La1-xCexNiO3 (x= 0 ~ 0.4) Perovskite-Type Oxide by Sol-Gel Using Polyvinyl Alcohol

2010 ◽  
Vol 434-435 ◽  
pp. 442-445 ◽  
Author(s):  
Kanit Soongprasit ◽  
Duangdao Aht-Ong ◽  
Viboon Sricharoenchaikul ◽  
Duangduen Atong
Keyword(s):  
Metal Ion ◽  
Sol Gel ◽  
Complexing Agent ◽  
Air Oxidation ◽  
X Ray Diffraction ◽  
Wet Air Oxidation ◽  
Energy Dispersion Spectroscopy ◽  
Sol Gel Process ◽  
Synthesized Materials ◽  
Perovskite Type

Perovskite-type oxides catalyst are of interest for various application such as auto-thermal reforming (ART), catalytic wet air oxidation (CWOA) and piezoelectric (PZT). In this paper, La1-xCexNiO3 (x= 0-0.4) perovskite-type oxides have been prepared b sol-gel process using PVA. The precursor was mixed metal ion and PVA with a mole ratio of 1:1 and 1:2. The decomposition during the calcinations process was evaluated by thermogravimetric analysis and differential thermal analysis. Phase of synthesized materials were characterized with X-ray diffraction. Morphological analysis and elemental composition of catalysts was determined by Scanning electron microscope and energy dispersion spectroscopy. The characterization results show that highly crystalline and homogeneous phase of these perovskite oxides were successfully synthesized by the sol-gel method via PVA as a complexing agent.

INFLUENCE OF THE INDEX METALLIC SALTS - COMPLEXING AGENT IN A SOL-GEL PROCESS TO OBTAIN NANOSCALED ZIRCONIUM SUBSTITUTED YTTRIUM (YSZ) TO ELECTROLYTE APPLICATION IN SOLID OXIDE FUEL CELL (SOFC)

2012 ◽  
Vol 1386 ◽  
Author(s):  
Rene Fabian Cienfuegos-Pelaes ◽  
Alejandro Ehécatl Correa ◽  
Ramona Alicia Salazar ◽  
L. Chávez-Guerrero ◽  
M. Hinojosa
Keyword(s):  
Low Cost ◽  
Sol Gel ◽  
Complexing Agents ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Crystalline Powder ◽  
Easy Method ◽  
X Ray ◽  
Metallic Salts ◽  
Sol Gel Process

ABSTRACTThe objective of the present study is to obtain the electrolyte material YSZ at low cost via sol gel, through exploration of the index rate between the complexing agents and the metallic salts (HMTA / metallic salts) from 1 to 5, prepared by a polymeric way in a sol gel process. We show an easy method that could be used in the industrial scale in order to obtain solid electrolyte material for its application in SOFC to operate at temperatures in the range of 700 800°C. This study has as reference the papers from Lenormand and Rieu about their synthesis of zirconium substituted to 8% of yttrium (CYSZ= 0.2 mol*L-1 metallic salts concentration-). The presence of the phase in the materials has been confirmed by X-ray diffraction assisted by thermal analysis tests, for indexes from 2 to 5 at a temperature of 1000°C for 5 hours at a calcination rate (from amorphous dust obtained at 400°C) of 1000°C per hour. The grain size mean for crystalline powder has an average near 50 nm and standard deviation close to 9 nm, it was confirmed by scanning electron microscope (SEM).

scholarly journals Characterization of LiCo Nanopowders Produced by Sol-Gel Processing

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Sina Soltanmohammad ◽  
Sirous Asgari
Keyword(s):  
Thermal Analyses ◽  
Sol Gel ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Size And Morphology ◽  
Gel Processing

LiCo nanopowders, one of the most important cathode materials for lithium-ion batteries, were synthesized via a modified sol-gel process assisted with triethanolamine (TEA) as a complexing agent. The influence of three different chelating agents including acrylic acid, citric acid, and oxalic acid on the size and morphology of particles was investigated. Structure and morphology of the synthesized powders were characterized by thermogravimetric/differential thermal analyses (TG/DTA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Results indicate that the powder processed with TEA and calcinated at 800 had an excellent hexagonal ordering of -NaFe-type (space group Rm). Also, the other three complexing agents had a decisive influence on the particle size, shape, morphology, and degree of agglomeration of the resulting oxides. Based on the data presented in this work, it is proposed that the optimized size and distribution of LiCo powders may be achieved through sol-gel processing using TEA as a chelating agent.

In Situ Radiation Damage Studies of Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12

2008 ◽  
Vol 1124 ◽  
Author(s):  
Karl R Whittle ◽  
Mark Blackford ◽  
Gregory R Lumpkin ◽  
Katherine L Smith ◽  
Nestor J Zaluzec
Keyword(s):  
Nuclear Waste ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Voltage Electron ◽  
Significant Difference ◽  
User Facility ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

AbstractGarnets, A3B2C3O12, are considered to be potential host phases for the immobilization of high-level nuclear waste as they can accommodate a number of elements of interest, including Zr, Ti and Fe. The naturally occurring garnet, kimzeyite, Ca3(Zr,Ti)2(Si,Al,Fe)3O12, can contain ˜30wt% Zr. An understanding of the radiation tolerance of these materials is crucial to their potential use in nuclear waste immobilization. In this study two synthetic analogues of kimzeyite of composition Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 were monitored in situ during irradiation with 1.0 MeV Kr ions using the intermediate voltage electron microscope-Tandem User Facility (IVEM) at Argonne National Laboratory. The structure of these materials was previously determined by neutron diffraction and 57Fe Mössbauer spectroscopy. Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 have very similar structural properties with cubic Ia3d symmetry, the only significant difference being the presence of Zr and Hf, respectively, on the 6 coordinated B sites.

Radiation Effects in Silicate Glasses - A Review

1988 ◽  
Vol 125 ◽  
Author(s):  
Ned E. Bibler ◽  
David G. Howitt
Keyword(s):  
Fiber Optics ◽  
Nuclear Waste ◽  
Radiation Effects ◽  
Alpha Particles ◽  
Phase Changes ◽  
Silicate Glasses ◽  
Atomic Displacements ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

ABSTRACTThe study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as high level nuclear waste immobilization and fiber optics. Radiation changes the properties of these glasses by altering their electronic and atomic configurations. These alterations or defects may cause dilatations or microscopic phase changes along with absorption centers that limit the optical application of the glasses. Atomic displacements induced in the already disordered structure of the glasses may affect their use where heavy irradiating particles such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may result. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions.In this paper, we review the literature concerning radiation effects on density, durability, stored energy, microstructure and optical properties of silicate glasses. Both simple glasses and complex glasses used for immobilization of nuclear waste are considered.

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