scholarly journals X-RAY DIFFRACTION OF SLAG-BASED SODIUM SALT WASTE FORMS

2014 ◽  
Author(s):  
C. Langton ◽  
D. Missimer
Keyword(s):  
Sodium Salt ◽  
X Ray Diffraction ◽  
X Ray ◽  
Waste Forms ◽  
Salt Waste

scholarly journals Bitumen Coating as a Tool for Improving the Porosity and Chemical Stability of Simulated Cement-Waste Forms

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
H. M. Saleh
Keyword(s):  
Experimental Tests ◽  
Waste Form ◽  
X Ray Diffraction ◽  
Microscope Examination ◽  
X Ray ◽  
Bitumen Emulsion ◽  
Waste Forms ◽  
Surrounding Environment ◽  
Simulated Waste ◽  
Physical And Chemical

Coating of simulated cement-based waste form was investigated by performing physical and chemical experimental tests. Moreover, X-ray diffraction, Fourier transform infrared spectroscopy, and electron microscope examination were applied on coated and noncoated simulated waste forms. Experimental results indicated that coating process improved the characterizations of cement-based waste form such as porosity and leachability. Diffusion coefficients and leach indecies of coated specimens were calculated and showed acceptable values. It could be stated that by coating cemented-waste form by bitumen emulsion, the radioactive contaminants were isolated, thus reducing the back release to surrounding environment during flooding by groundwater and consequently, saving the environment.

The mixed-valent 10-manganese(III/IV)-containing 36-tungsto-4-arsenate(V), [MnIII 6MnIV 4O4(OH)12(H2O)12(A-β-AsW9O34)4]22−

2018 ◽  
Vol 74 (11) ◽  
pp. 1390-1394 ◽  
Author(s):  
Rami Al-Oweini ◽  
Bassem S. Bassil ◽  
Marwa Itani ◽  
Dilara Börte Emiroğlu ◽  
Ulrich Kortz
Keyword(s):  
Ir Spectroscopy ◽  
Single Crystal ◽  
Sodium Salt ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Potassium Sodium ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Interaction of the mixed-valent 12-manganese coordination complex [MnIII 8MnIV 4O12(CH3COO)16(H2O)4] with the lacunary 9-tungstoarsenate(V) [A-α-AsW9O34]9− resulted in the 10-manganese(III/IV)-containing 36-tungsto-4-arsenate(V), [MnIII 6MnIV 4O4(OH)12(H2O)12(A-β-AsW9O34)4]22− (1). Polyanion 1 was isolated as a hydrated mixed potassium–sodium salt, K14Na8[MnIII 6MnIV 4O4(OH)12(H2O)12(A-β-AsW9O34)4]·104H2O, which crystallizes in the orthorhombic space group Pbcn and was characterized by FT–IR spectroscopy and single-crystal X-ray diffraction, as well as elemental and thermogravimetric analyses. The title polyanion contains a unique [MnIII 6MnIV 4O4(OH)12(H2O)12]14+ core stabilized within the 36-tungsto-4-arsenate(V) framework.

Evaluation of thermally converted silicotitanate waste forms

1999 ◽  
Vol 556 ◽  
Author(s):  
Y. SU ◽  
M. L. Balmer ◽  
L. Wang ◽  
B. C. Bunker ◽  
M. Nyman ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Thermal Conversion ◽  
X Ray Diffraction ◽  
Ion Exchangers ◽  
Waste Streams ◽  
Silicate Phase ◽  
X Ray ◽  
Waste Forms ◽  
Heat Treated ◽  
Crystalline Silicotitanate

AbstractCrystalline silicotitanate ion exchangers are highly selective for separating Cs from Narich waste streams. However, use of these ion exchangers for removal of Cs from radioactive tank waste will result in large volumes of secondary wastes. Thermal conversion of silicotitanates produces a durable waste form with reduced volumes up to 40%. Leach tests (MCC-l and PCT) have shown that Cs leach rates of IE-91 1-Na (heat treated at 900°C for an hour) are extremely low, ranging from 0.1 to lwt% Cs loss in Cs fraction release, or 10-1 to 10-8g/m2day in normalized Cs mass loss. These are several orders of magnitude lower than that of borosilicate glass. In order to understand the interplay between the structure and high Cs durability, X-ray diffraction, 133Cs NMR, and thermogravimetric analysis have been used to identify phase(s) responsible for trapping Cs in these silicotitanates. Results indicate that Cs is likely to be contained in a crystalline silicate phase.

Iodine Waste Forms: Calcium Aluminate Hydrate Analogues

1984 ◽  
Vol 44 ◽  
Author(s):  
Dale R. Brown ◽  
Michael W. Grutzeck
Keyword(s):  
Room Temperature ◽  
X Ray Diffraction ◽  
Wet Chemistry ◽  
X Ray ◽  
Leach Rate ◽  
Waste Forms ◽  
Excess Water ◽  
Calcium Aluminate Hydrate ◽  
End Members

AbstractPhase relations in the system 3CaO·AI2O3-CaSO4-CaI2-H2O in equilibrium with excess water were established by means of room temperature bottle hydration of various bulk chemistries in the system. Starting with end members ettringite (3CaO·Al2O3·3CaSO4·32H2O) and tetracalcium aluminate monosulfate-12-hydrate (3CaO·Al2O3-CaSO4-12H2O), iodine-substituted analogue phases were synthesized which containe increasingly greater percentages of iodine. The iodine-substituted ettringite was found to be unstable whereas the iodine-substituted monosulfate formed readily. SEM, wet chemistry, IR, and x-ray diffraction characterization of the latter phase suggest that its formula is 3CaO·Al2O3·Ca(IO3)2·2H2O. Cement pellets containing this “Afm” iodine-substituted phase were subjected to a modified MCC-1 static leach test. Although the normalized iodine leach rate was relatively high when compared with AgI encapsulated in portland Type III cement, this same leach rate was approximately equal to the rates that have been reported for Ba(IO3)2, Ca(IO3)2, and Hg(IO3)2 in portland cement. The normalized iodine leach rate obtained also was found to be roughly comparable to that given for I-sodalite in cement. Diffusion is indicated as the primary leach mechanism, becoming dominant after the first three days of leaching.

Effect of pressure on slit channels in guanine sodium salt hydrate: a link to nucleobase intermolecular interactions

CrystEngComm ◽  
2019 ◽  
Vol 21 (30) ◽  
pp. 4484-4492 ◽  
Author(s):  
Anna A. Gaydamaka ◽  
Sergey G. Arkhipov ◽  
Boris A. Zakharov ◽  
Yurii V. Seryotkin ◽  
Elena V. Boldyreva
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
Single Crystal ◽  
Intermolecular Interactions ◽  
Sodium Salt ◽  
X Ray Diffraction ◽  
Salt Hydrate ◽  
X Ray ◽  
Effect Of Pressure

The crystal structure of a hydrate of the sodium salt of guanine (2Na+·C5H3N5O2−·7H2O) was studied at high pressure by single-crystal X-ray diffraction and Raman spectroscopy.

Alpha-Decay Damage and Annealing Effects in Natural Pyrochlores: Analogues for Long-Term Radiation Damage Effects in Actinide, Pyrochlore, Structure Types

1988 ◽  
Vol 127 ◽  
Author(s):  
G. R. Lumpkin ◽  
R. C. Ewing
Keyword(s):  
Pyrochlore Structure ◽  
Alpha Decay ◽  
X Ray Diffraction ◽  
Final State ◽  
X Ray ◽  
Waste Forms ◽  
Annealing Effects ◽  
Long Term Performance ◽  
Term Performance

ABSTRACTCubic pyrochlore structure types, A2-mB2O6(O, OH, F) i-n*pH2O, and their derivatives (e.g., monoclinic zirconolite) are important actinide-bearing phases in polyphase, ceramic waste forms (e.g., SYNROC). These waste form phases may typically accumulate alpha-decay doses of 1025 alpha-events/m3 in 1, 000 years or 1026alpha-events/m3 in one million years (i.e., for SYNROC with 20 wt. % HLW). Natural pyrochlores have calculated doses ranging from 1024 to 1027 alpha-events/m3 (= 0.02 to 50 dpa) which have accumulated over ten to a thousand million years. Actinide doping experiments typically reach doses of 1025 alpha-events/m3over periods of several years. Detailed x-ray diffraction analysis of natural samples reveals that the alpha-decay dose at which there is an initial loss of crystallinity (i.e., transition from crystalline to the aperiodic, metamict state as a result of alpha-decay damage) increases as a function of the geologic age of the sample. The increase in the calculated alpha-decay dose which is associated with a specific degree of damage (e.g., loss of x-ray diffraction intensity) is attributed to annealing of isolated alpha-recoil tracks back to the original, crystalline structure. Based on a model of gradual track fading, the alpha-recoil tracks in natural pyrochlores have mean lives on the order of 108 years. In contrast, minerals which remain crystalline (e.g., uraninite, UO2) despite doses of over 1027 alpha-events/m3 have mean alpha-recoil track lives of approximately 104 years. This demonstrates that the microstructure of alpha-decay damaged materials depends not only on the total alpha-event dose, but also on the annealing kinetics of alpha-recoil track fading. Therefore, the prediction of the long-term performance and final state of crystalline phases in ceramic nuclear waste forms requires the determination of alpha-recoil damage annealing as a function of time and temperature.

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