The Role of Boron in Monitoring the Leaching of Borosilicate Glass Waste Forms

1984 ◽  
Vol 44 ◽  
Author(s):  
Barry E. Scheetz ◽  
W. Phelps Freeborn ◽  
Deane K. Smith ◽  
Christine Anderson ◽  
Michael Zolensky ◽  
...  
Keyword(s):  
Borosilicate Glass ◽  
Solid Phase ◽  
Waste Form ◽  
Direct Measure ◽  
Glass Waste ◽  
Worst Case ◽  
Waste Forms

AbstractIn the absence of any identified solid phase host (other than the original glass), boron has been assumed to accumulate in the fluid during the reaction of borosilicate glass waste forms with aqueous fluids. Using this assumption, it is possible to define a boron index which can be used to monitor the amount of glass that has been dissolved and to provide a worst-case measure of the degradation of the primary glass waste form. Several boron-containing silicate phases have been identified thus invalidating the assumption that boron does not precipitate. The effect is apparently small and the assumption that boron release is a direct measure of degree of alteration of borosilicate glass is still probably a good one.

Ion Implantation Studies of Nuclear Waste Forms

1981 ◽  
Vol 6 ◽  
Author(s):  
Clyde J. M. Northrup ◽  
George W. Arnold ◽  
Thomas J. Headley
Keyword(s):  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Alpha Decay ◽  
Lead Ions ◽  
Waste Form ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Waste Forms ◽  
Basic Studies ◽  
Nuclear Waste Forms

ABSTRACTThe first observations of physical and chemical changes induced by lead implantation damage and leaching are reported for two proposed U.S. nuclear waste forms (PNL 76–68 borosilicate glass and Sandia titanate ceramics) for commercial wastes. To simulate the effects of recoil nucleii due to alpha decay, the materials were implanted with lead ions at equivalent doses up to approximately 1 × 1019 a decays/cm3 . In the titanate waste form, the zirconolite, perovskite, hollandite, and rutile phases all exhibited a mottled appearance in the transmission electron microscope (TEM) typical of defect clusters in radiation damaged, crystalline solids. One titanate phase containing uranium was found by TEM to be amorphous after implantation at the highest dose. No enhanced leaching (deionized water, room temperature, 24 hours) of the irradiated titanate waste form, including the amorphous phase, was detected by TEM, but Rutherford backscattering (RBS) suggested a loss of cesium and calcium after 21 hours of leaching. The RBS spectra also indicated enhanced leaching from the PNL 76–68 borosilicate glass after implantation with lead ions, in general agreement with the observations of Dran, et al. [6,7] on other irradiated materials. Elastic recoil detection spectroscopy (ERD), used to profile hydrogen after leaching, showed penetration of the hydrogen to several thousand angstroms for both the implanted and unimplanted materials. These basic studies identified techniques to follow the changes that occur on implantation and leaching of complex amorphous and crystalline waste forms. These studies were not designed to produce comparisons between waste forms of gross leach rates.

New Crystalline Silicotitanate (CST) Waste Forms: Hydrothermal Synthesis and Characterization of CS-SI-TI-O Phases

1999 ◽  
Vol 556 ◽  
Author(s):  
M. Nyman ◽  
T. M. Nenoff ◽  
Y. Su ◽  
M. L. Balmer ◽  
A. Navrotsky ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Hydrothermal Synthesis ◽  
Ion Exchange ◽  
Borosilicate Glass ◽  
Waste Form ◽  
Synthesis And Characterization ◽  
Hanford Site ◽  
Waste Forms ◽  
Crystalline Silicotitanate

AbstractThe radioactivity of the Hanford site waste tanks is primarily from 137Cs and 90Sr, of which can both be selectively removed from solution using a crystalline silicotitanate (CST) ion exchanger. We are currently seeking waste forms alternative to borosilicate glass for Cs-CSTs. In order to obtain a fundamental basis for the development of an alternative waste form, we are investigating synthesis and characterization of CST component phases, namely Cs-Si-Ti-O phases. Two novel Cs-Ti-Si-O phases (one porous, one condensed) have been hydrothermally synthesized, characterized and evaluated as waste form candidates based on chemical and thermal stability, leachability, and ion exchange capabilities.

Dissolution of Technetium From Nuclear Waste Forms

1983 ◽  
Vol 26 ◽  
Author(s):  
M. Yasser Khalil ◽  
William B. White
Keyword(s):  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Stability Field ◽  
Glass Waste ◽  
Waste Forms ◽  
Reducing Conditions ◽  
Valence States ◽  
The Stability ◽  
Nuclear Waste Forms ◽  
Similar Kinetic

ABSTRACTThe immobilization of 99Tc in both ceramic and borosilicate glass waste forms and the mechanism of dissolution of technetium from these waste forms are complicated by the range of technetium valence states. Metallic Tc,ionic Tc4+ oxides, and volatile molecular species containing Tc7+ all occur within the stability field of water. Tc4+ will substitute readily for Ti4+ in titanatebased ceramics in such phases as perovskite (CaTiO3) and spinel (Mg2TiO4). Tc4+ can be homogeneously distributed in borosilicate glass by re-melting the glass under closed system conditions to prevent the re-oxidation of technetium. The dissolution of technetium from both glass and ceramic waste forms follow similar kinetic behavior although the dissolution rate from the titanate is two orders of magnitude lower. Dissolution under highly reducing conditions is too slow to measure on the time scale of the experiments.

scholarly journals Incorporation of High-Level Wastes in Synroc: Results from Recent Process Engineering Studies at Lawrence Livermore National Laboratory

1981 ◽  
Vol 11 ◽  
Author(s):  
J. H. Campbell ◽  
C. L. Hoenig ◽  
F. J. Ackerman ◽  
P. E. Peters ◽  
J. Z. Grens
Keyword(s):  
Borosilicate Glass ◽  
Selection Process ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Process Engineering ◽  
Waste Form ◽  
Performance Properties ◽  
Engineering Studies ◽  
Waste Forms ◽  
High Level

In October 1981 SYNROC-D was selected as the reference alternate waste form to borosilicate glass for immobilization of defense wastes. A total of eight candidate waste forms competed in this selection process and the decision of which alternate waste form to choose was based primarily on performance properties.

scholarly journals The Role of Residual Contaminants and Recycling Steps on Rheological Properties of Recycled Polypropylene

2021 ◽  
Author(s):  
Robert da Silva Paiva ◽  
Isabelly Bertochi Veroneze ◽  
Magdalena Wrona ◽  
Cristina Nerín ◽  
Sandra Andrea Cruz
Keyword(s):  
Molecular Structure ◽  
Solid Phase ◽  
Case Scenario ◽  
Worst Case ◽  
Molecular Changes ◽  
Shear Rates ◽  
Food Simulants ◽  
Oscillatory Rheometry ◽  
The Impact

Abstract Recycling of polymers is one of the alternatives to reduce the impact of polymers presence on the environmental. However, the contaminants, defined as non-intentionally added substances, present in recycled material may migrate into food and also change its molecular structure. This work addresses the extractability/migration of contaminants from polypropylene (PP) samples into food simulants and the influence of these contaminants on the molecular structure of recycled PP. For this PP was contaminated with several substances to simulate a “worst-case” scenario and, then it was submitted to a recycling process. Extractability tests were performed by solid-phase microextraction and gas chromatography coupled to mass spectroscopy both to evaluate the presence of contaminants in the PP samples and their ability to migrate in food simulants. Additionally, molecular changes of the PP samples were evaluated by oscillatory rheometry. After washing and extrusion of the PP samples the extractability results showed considerable reductions of migrations in the food simulants and indicated, in some cases, compliance with regulations for using recycled polymer in contact with food. The residual contaminants were present in the polymer, the high temperatures and shear rates play an important role in molecular changes. Finally, the results highlight the importance of the use of rheological measurements to detect the influence of contaminants in recycled materials. Their presence result in material with different molar mass, that may be applied in different market applications.

Long-Term Release Rates of Borosilicate Glass Waste Forms

1986 ◽  
Vol 73 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Pedro B. Macedo ◽  
Aaron Barkatt ◽  
Barbara C. Gibson ◽  
Charles J. Montrose
Keyword(s):  
Borosilicate Glass ◽  
Release Rates ◽  
Glass Waste ◽  
Waste Forms

Ecological Silicate Glasses

2008 ◽  
Vol 39-40 ◽  
pp. 667-670 ◽  
Author(s):  
Bogdan Alexandru Sava ◽  
Adriana Diaconu ◽  
Luminita Daniela Ursu ◽  
Lucica Boroica ◽  
M. Elisa ◽  
...  
Keyword(s):  
Borosilicate Glass ◽  
Raw Materials ◽  
Structural Data ◽  
Refraction Index ◽  
Titanium Oxides ◽  
Glass Waste ◽  
Oxide Systems ◽  
High Annealing ◽  
Fluorine Compounds

The investigated ecological glasses with no toxic compounds, such as BaO, PbO, As2O3, As2O5, fluorine, CdS and CdSe in their composition are located in ternary and quaternary oxide systems: ZnO-SiO2-TiO2 and SiO2-R'2O-R''O-R'''O2, where R' is Na or K, R'' is Ca or Mg and R''' is Zr or Ti. The first system contains P2O5, ZnO and TiO2 in order to obtain opal glasses, without fluorine compounds. The second system replaces the barium oxide and lead oxide with potassium, magnesium, zirconium and titanium oxides, for materials like lead free crystals. The raw materials can be replaced by silicate or borosilicate glass waste. The advantages of borosilicate glass waste are: bringing valuable components into recipes (B2O3, CaO, Al2O3), saving raw materials and energy, creating an ecological environment The characteristic temperatures (vitreous transition point, low and high annealing points, softening point) and the thermal expansion coefficient of the glass are presented. The FTIR and Raman spectroscopy provided structural data, such as characteristic vibration maxima for silicon and titanium oxide, and revealed the role of zinc oxide in the vitreous network. The refraction index and UV-VIS transmission are discussed.

Mechanical integrity of yttria-stabilised zirconia doped with Np oxide

2006 ◽  
Vol 932 ◽  
Author(s):  
Hajime Kinoshita ◽  
Ken-ichi Kuramoto ◽  
Masayoshi Uno ◽  
Shinsuke Yamanaka ◽  
Hisayoshi Mitamura ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Young’S Modulus ◽  
Elastic Deformation ◽  
Borosilicate Glass ◽  
Young's Modulus ◽  
Crack Development ◽  
Waste Form ◽  
Mechanical Integrity ◽  
Waste Forms

ABSTRACTMechanical properties of YSZ doped with Np oxide were studied to investigate the sufficiency to be a waste form for immobilisation of highly concentrated TRU. The study was conducted focusing on Vickers (HV) and Knoop (HK) hardness, Young's modulus (E) and fracture toughness (KIC). The results showed that YSZ is harder and more resistant to elastic deformation and crack development than such waste forms as borosilicate glass and synroc. The effects of porosity and Np content on HV, HK, E and KIC are also discussed.

Screening of Candidate Low‐Temperature Glass Waste Forms for Technetium from Hanford Effluent Management Facility Evaporator Bottoms

2018 ◽  
Author(s):  
Rebecca M. Chamberlin ◽  
Ming Tang ◽  
Rosendo Borjas Nevarez ◽  
Gordon Dennis Jarvinen ◽  
Daniel Koury ◽  
...  
Keyword(s):  
Low Temperature ◽  
Glass Waste ◽  
Waste Forms

Introduction to geomicrobiology

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Fossil Fuels ◽  
Solid Phase ◽  
Direct Reduction ◽  
Iron Oxidation ◽  
Mineral Dissolution ◽  
Precipitation Process ◽  
Soluble Ions ◽  
Chemolithoautotrophic Bacteria ◽  
The Impact

Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.

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