Application of inorganic sorbent in actinide separation processes

For several reasons--poor hydraulic behavior, unsatisfactory sorption kinetics, unavailability, in some cases of commercial quantities, etc.--inorganic sorbents have not heretofore been used extensively in the backend of the nuclear fuel cycle. A potential breakthrough in plant scale application of such sorbents in nuclear liquid waste treatment may ensue from research currently underway at several U.S. Department of Energy sites. At Mound Laboratories, calcium hydroxyapatite (Ca/sub 10/(PO/sub 4/)/sub 6/(OH)/sub 2/), obtained from the Kerr-McGee Co., has been shown in both batch and column tests to effectively remove /sup 238/Pu from certain aqueous wastes generated there; costs and benefits of incorporation of one or more beds of Ca/sub 10/(PO/sub 4/)/sub 6/(OH)/sub 2/ in the Mound Laboratory waste treatment circuit are being evaluated. An ion exchange process which takes advantage of the great affinity and capacity of sodium titanate (Na(Ti/sub 2/O/sub 5/H)) for greater than or equal to +2 ions from high alkaline salt solutions has been successfully developed and demonstrated for reduction of plutonium and /sup 241/Am concentrations of Hanford Plutonium Reclamation Facility salt waste to drinking water levels. Batch distribution data obtained at Sandia Laboratories indicates Na(Ti/sub 2/O/sub 5/H) may also be useful in chromatographic separation of Am/sup 3 +/ and Cm3/sup +/. Pertinent properties of these inorganic sorbents as well as separation process flowsheets and data are reviewed in this paper

Chemical analysis of thin films at Sandia National Laboratories

The characterization of thin films produced by chemical and physical vapor deposition requires special analytical techniques. When the average compositions of the films are required, dissolution of the thin films and measurement of the concentrations of the solubilized species is the appropriate analytical approach. In this report techniques for the wet chemical analysis of thin films of Si:Al, P/sub 2/O/sub 5/:SiO/sub 2/, B/sub 2/O/sub 3/:SiO/sub 2/, TiB/sub x/ and TaB/sub x/ are described. The analyses are complicated by the small total quantities of these analytes present in the films, the refractory characters of these analytes, and the possibility of interferences from the substrates on which the films are deposited. Etching conditions are described which dissolve the thin films without introducing interferences from the substrates. A chemical amplification technique and inductively coupled plasma atomic emission spectrometry are shown to provide the sensitivity required to measure the small total quantities (micrograms to milligrams) of analytes present. Also the chemical analysis data has been used to calibrate normal infrared absorption spectroscopy to give fast estimates of the phosphorus and/or boron dopant levels in thin SiO/sub 2/ films

PbO-free glasses for low temperature packaging

Zinc polyphosphate glasses were examined as potential candidates for low temperature sealing applications. Glass-formation and properties were determined for the ZnO-P{sub 2}O{sub 5}, ZnO-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} and ZnO-SnO-P{sub 2}O{sub 5} systems, and information about the short-range structures of these glasses was obtained by Raman and solid state nuclear magnetic resonance spectroscopies. In general, the most durable polyphosphate glasses have structures based on relatively short pyrophosphate chain lengths (i.e., 2 P-tetrahedra). Modified phosphate compositions are given, including compositions used to seal float glass substrates at temperatures as low as 500{degrees}C

Advanced materials for aerospace and biomedical applications: New glasses for hermetic titanium seals

Titanium and titanium alloys have an outstanding strength-to-weight ratio and corrosion resistance and so are materials of choice for a variety of aerospace and biomedical applications. Such applications are limited by the lack of a viable hermetic glass sealing technology. Conventional silicate sealing glasses are readily reduced by titanium to form interfacial silicides that are incompatible with a robust glass/metal seal. Borate-based glasses undergo a similar thermochemistry and are reduced to a titanium boride. The kinetics of this reactions, however, are apparently slower and so a deleterious interface does not form. Chemically durable lanthanoborate glasses were examined as candidate sealing compositions. The compositions, properties, and structures of several alkaline earth, alumina, and titania lanthanoborate glass forming systems were evaluated and this information was used as the basis for a designed experiment to optimize compositions for Ti-sealing. A number of viable compositions were identified and sealing procedures established. Finally, glass formation, properties, and structure of biocompatible Fe{sub 2}O{sub 3}- and TiO{sub 2}-doped calcium phosphate systems were also evaluated

Chemical reactivity and the structure of gels

The structures of sel-gel-derived networks are a product of a series of condensation reactions. In solution, the evolving structures are limited to species which are stable in the synthesis medium (alcohol/water). During consolidation metastable species form, which are temporarily stabilized by the high viscosity of the surrounding matrix. Chemical reactivity of gel-derived networks provides insight to their structure and vice versa

Raman Analysis of Inorganic Thin Films*

Techniques for the Raman analysis of plasma-deposited submicrometer silicon films on metallic substrates and dielectric films on Raman-active substrates will be described and typical results will be presented.</jats:p

Instability of Polyvinylidene Fluoride-Based Polymeric Binder in Lithium-Ion Cells: Final Report

Thermal instabilities were identified in SONY-type lithium-ion cells and correlated with interactions of cell constituents and reaction products. Three temperature regions of interaction were identified and associated with the state of charge (degree of Li intercalation) of the cell. Anodes were shown to undergo exothermic reactions as low as 100 degree C involving the solid electrolyte interface (SEI) layer and the LiPF(6) salt in the electrolyte (EC-PC:DEC/IM LiPF(6)). These reactions could account for the thermal runaway observed in these cells beginning at 100 degree C. Exothermic reactions were also observed in the 200 degree C to 300 degree C region between the intercalated lithium anodes, the LiPF(6) salt, and the PVDF. These reactions were followed by a high-temperature reaction region, 300 degree C to 400 degree C, also involving the PVDF binder and the intercalated lithium anodes. The solvent was not directly involved in these reactions but served as a moderator and transport medium. Cathode exothermic reactions with the PVDF binder were observed above 200 degree C and increased with the state of charge (decreasing Li content). The stability of the PVDF binder as a function of electrochemical cycling was studied using FTIR. The infrared spectra from the extracts of both electrodes indicate that PVDF is chemically modified by exposure to the lithium cell electrolyte (as well as electrochemical cycling) in conjunction with NMP extraction. Preconditioning of PVDF to dehydrohalogenation, which may be occurring by reaction with LiPf(6), makes the PVDF susceptible to attack by a range of nucleophiles