Preparation and Properties of Lead-Iron-Phosphate Nuclear Waste Glasses
Abstract: Lead-iron phosphate (LIP) glasses are a promising new waste form for safe immobilization of both high level defence and high level commercial radioactive waste for long term disposal. LIP glasses h...
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02 Oct 2022
TL;DR: In this article , the impact of Cerium Oxide (CeO2) nanoparticles on corrosion protection properties is discussed. But, the authors focus on the effect of grain size, cracking, pore size, microstructure, and micro-hardness on the performance of these nanoparticles.
Abstract: Cerium oxide (CeO2) nanoparticles have emerged as a significant nanomaterial in a wide range of applications, including photocataly sis, corrosion inhibitors, and biological applications. T he corrosion resistance hy brid film based on CeO 2 nanoparticles turns into a more remarkable inhibitor than hazardous chromate-based protective materials. In this review, we present the impact of CeO2 nanoparticles on corrosion protective properties; synthesis of CeO2 nanoparticles by a green and chemical process; protective CeO2 coating deposited on the substrate by different methods; CeO2-based orga nic coa tings; CeO2-based in organi c coa tings and tribological behavior of CeO2. Also, it enlightens the influence of grain size, cracking, pore size, microstructure, and micro-hardness on CeO2-based corrosion coatings. Investigations into the effects of corrosion found that CeO2-based coatings had high potential and a drop in current densities, which are responsible for the inhibitory performance. Additionally, the inclusion of CeO2 nanoparticles results in finer-grained deposits with improved corrosion resistance. M ost CeO2 coatings display good corrosion resistance compared to other potential organic and inorganic composite coatings addressed in this section.
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01 Jul 1982
TL;DR: In this paper, the authors present an approach to the formation of a glass, including two phases of transformation in glass, and the theory of chemical bonding in transition metal complexes, as well as acid-base relations in glass.
Abstract: 1 Glass Formation.- 1.1 General Aspects.- 1.2 Glass Formers.- 1.3 Atomistic Hypotheses of Glass Formation.- 1.4 Kinetic Approach to Glass Formation.- 2 Phase Transformations in Glass.- 2.1 Crystallization.- 2.2 Liquid -Liquid Phase Separation.- 2.3 Glass-Ceramics.- 3 Physical Properties.- 3.1 Density of Glasses.- 3.2 Partial Molar Volume of Constituent Oxides in Glasses and Melts.- 3.3 Refractive Index of Glasses.- 3.4 Thermal Expansion of Glasses.- 3.5 Viscosity of Glasses.- 3.6 Surface Tension of Glasses.- 3.7 Electrical Properties of Glasses.- 4 Chemical Durability of Glass.- 4.1 Mechanism of Reactions of Glasses with Aqueous Solution.- 4.2 Factors Affecting Chemical Durability Measurements of a Glass.- 4.3 Effect of Glass Composition.- 4.4 Effect of pH of the Solution on Chemical Durability of SiO2 (quartz).- 4.5 Solubility of Silica in Aqueous Solutions.- 4.6 Glass Electrodes.- 5 Oxidation-Reduction Equilibrium in Glass.- 5.1 General.- 5.2 Activity Corrections.- 5.3 Oxidation -Reduction in Glass.- 5.4 Theory of Redox Reactions in Solutions.- 6 Acid-Base Concepts in Glass.- 6.1 Introduction.- 6.2 Acid-Base Relationships in Glasses.- 6.3 Oxygen Ion Activity.- 6.4 Transition Metal Ions as Acid-Base Indicators in Glass.- 6.5 Oxidation-Reduction Equilibrium in Glass.- 6.6 Filled Shell Ions with ns2 Configuration as an Acid-Base Indicator in Glass.- 6.7 Vanadylion as an Acid-Base Indicator in Glass.- 7 Coloured Glasses.- 7.1 Atomic Structure and the Periodic Classification of Transition Metals.- 7.2 Theories of Chemical Bonding in Transition Metal Complexes.- 7.3 Application of Bonding Theories in Interpreting d-d Absorption Spectra.- 7.4 Absorption Spectra of Transition Metal Ions.- 7.5 Charge-Transfer Bands.- 7.6 Anionic Substitution in Glass.- 7.7 Photosensitive Glasses.- 7.8 Copper Ruby Glasses.- 7.9 Measurement of Colour, Colour Diagram and Tristimulus Values.- 8 Polymetric Nature of Glass Melts.
702 citations
TL;DR: An overview of the immobilization of high level radioactive waste (HLW) and surplus materials from a variety of commercial and defence sources employing glass and ceramics is given in this article.
Abstract: An overview is given of the immobilization of high level radioactive waste (HLW) and surplus materials from a variety of commercial and defence sources employing glass and ceramic hosts. A number of specific host materials are reviewed, including borosilicate and phosphate glasses, glass-ceramics and crystalline ceramics. Topics covered include wasteform processing and manufacture, in addition to wasteform stability, durability and mechanical behaviour. Although, at the present time, borosilicate glass is the generally accepted first generation wasteform for the immobilization of HLW, the emergence of new sources of radioactive materials requiring immobilization has renewed interest in many of the alternative candidates. These include, in particular, titanate, zirconate and phosphate based ceramics, together with iron phosphate based glasses and basaltic glass-ceramics. The relative merits and limitations of each host material are compared and discussed, with particular reference to processing considerations and to current and likely future requirements.
622 citations
TL;DR: In this paper, the depolymerization of P metaphosphate chains by the addition of ZnO is quantitatively described by the increase in the concentration of Q 1 -phosphate sites, determined from the 31 P MAS-NMR spectra.
Abstract: 31 P magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy and Raman spectroscopy have been used to examine the polyhedral arrangements in x ZnO · (1 − x )P 2 O 5 (0.50 ≤ x ≤ 0.71) glasses. The depolymerization of P metaphosphate chains by the addition of ZnO is quantitatively described by the increase in the concentration of Q 1 -phosphate sites, determined from the 31 P MAS-NMR spectra. When x > 0.60, the NMR and Raman spectra exhibit peaks due to Q 0 and Q 2 tetrahedra, indicating that structures disproportionate in glass melts near the pyrophosphate composition. The splitting of the Raman peak due to the Q 1 terminal oxygen stretching mode indicates that a variety of P-O-Zn bonds participate in the polyphosphate glass structure. The complex mixture of P and Zn polyhedra contributes to the glass-forming tendency of the high ZnO (> 60 mol%) compositions.
459 citations
TL;DR: In this article, the properties of phosphate glasses, containing from 14 to 43 mol% Fe2O3 and up to 13 mol% Na2O, have been measured, and the outstanding chemical durability of these glasses was attributed to the replacement of PO ǫP bonds by more chemically resistant PO Ã Ã P bonds.
Abstract: Selected properties of phosphate glasses, containing from 14 to 43 mol% Fe2O3 and up to 13 mol% Na2O, have been measured. With increasing Fe2O3 and Na2O content, the density and dilatometric softening temperature increased, whereas, the thermal expansion coefficient and dissolution rate in water or saline at 90°C decreased. Glasses containing more than 25 mol% Fe2O3 had an exceedingly good chemical durability. Their dissolution rate at 90°C in distilled water or in saline solution was up to 100 times lower than that of window glass. Mossbauer and X-ray photoelectron spectroscopy indicate that iron(II) and iron(III) were both present in the glasses and the chemical durability improved with increasing iron(III) concentration. The outstanding chemical durability of these glasses was attributed to the replacement of POP bonds by more chemically resistant POFe(II) and POFe(III) bonds.
274 citations
TL;DR: In this paper, the authors obtained the oxidation-reduction equilibria in molten glasses having a soda/silica ratio of 1/2 and containing small amounts of variable-valence ions of the transition elements titanium, vanadium, iron, cobalt, and nickel, the post-transition elements tin and antimony, and the rare-earth element cerium.
Abstract: The oxidation-reduction equilibria in molten glasses having a soda/silica ratio of 1/2 and containing small amounts of variable-valence ions of the transition elements titanium, vanadium, iron, cobalt, and nickel, the post-transition elements tin and antimony, and the rare-earth element cerium were obtained by equilibrating the melts with various atmospheres. The simple mass expression
was always applicable. In the expression, n is the number of electrons involved in the valence change of the metal M. The value of n is 1 for all systems except for the ions of antimony and tin where n is 2. The ions found are those generally accepted as existing in glass melts which are Ti3+, Ti4+; Fez+, Fe3+; Ce3+, Ce4+; Mn2+, Mn3; Co2+, Co3+; Ni2+, Ni3; Sb3+, Sb5+; and Sn2+, Sn4+. Two mass action expressions were needed for vanadium-containing glasses to describe the equilibria between 5+, 4+, and 3 f species.
157 citations