The Thermochemical Properties of the Oxides, Fluorides, and Chlorides to 2500 K

Glassner, Alvin

doi:10.2172/4348903

Cited by 102 publications

(57 citation statements)

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“…Ryan (Burger et al 1973) observed some volatilization from the nitrate/nitrite system at 1075 K to 1125 K and a large loss at 1200, K to 1225 K. Volatilization as N%0 would require about 117 kJ/mol (Glassner 1958). However, N%O has negligible volatility at 1200 K (Brewer and Margrave 1955).…”

Section: Thermal Data For Compoundsmentioning

confidence: 99%

Calculation of reaction energies and adiabatic temperatures for waste tank reactions

Burger¹

1993

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SummaryContinual concern has been expressed over potentially hazardous exothermic reactions that might occur in Hanford Site underground waste storage tanks. These tanks contain many different oxidizable compounds covering a wide range of concentrations. Several compounds may be in concentrations and quantities great enough to be considered a hazard in that they could undergo rapid and energetic chemical reactions with nitrate and nitrite salts that are present it heated to the initiating or critical temperature. The chemical hazards are a function of several interrelated factors, including the amount of energy (heat) produced, how fast it is produced, and the thermal absorption and heat transfer properties of the system. The reaction path(s) will determine the amount of energy produced and kinetics will determine the rate that it is produced. The tanks also contain many inorganic compounds inert to oxidation. These compounds act as diluents and can inhibit exothermic reactions because of their heat capacity and thus, in contrast to the oxidizable compounds, provide mitigation of hazardous reactions.In this report the energy that may be released when various organic and inorganic compounds react is computed as a function of the reaction-mix composition and the temperature. The enthalpy, or integrated heat capacity, of these compounds and various reaction products is presented as a function of temperature; the enthalpy of a given mixture can then be equated to the energy release from various reactions to predict the maximum temperature which may be reached. This is estimated for several different compositions. Alternatively, the amounts of various diluents required to prevent the temperature from reaching a critical value can be estimated. Reactions W i g different paths, forming different products such as N20 in place of N2 are also considered, as are reactions where an excess of caustic is present. Oxidants other than nitrate and nitrite are considered briefly.The relative available energy per unit mass of the various oxidizable compounds, or "fuels," that may be present ranges from 1 to about 25. Stoichiometric mixes with oxidant, e.g., fuel plus the required amount of sodium nitrate (NaNO,) for a complete reaction, compared on a mass basis, also show large differences. This "energy density" covers a range of 1 to about 5.A consequence of different stoichiometries for different fuels is that an excess of sodium nitrate or nitrite for one reactant may be a deficiency for another. This is significant since excess nitrate or nitrite is an excellent heat sink, especially at elevated temperatures.The efficiency of various compounds as heat sinks, i.e., their enthalpies, vary greatly. In the wastes water is the most significant material at temperatures up to slightly above 100°C. From 100°C to about 300°C the greatest effect is probably from hydrated salts, with some contribution from concentrated caustic solutions. The loss of water from these materials requires a large energy input, some 50% to 100% greater than f...

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Section: Thermal Data For Compoundsmentioning

confidence: 99%

Calculation of reaction energies and adiabatic temperatures for waste tank reactions

Burger¹

1993

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“…By combination of r e a c t i o n s (1) ' a n d ( 6 ) When a molten m i x t u r e c o n t a i n i n g only LiF, BeF2, and UF4 i s t r e a t e d w i t h a p p r e c i a b l e q u a n t i t i e s of a r e a c t i v e oxide ( s u c h a s H 0 , C O ; , F~O ) 2 p r e c i p i t a t i o n of UO r e s u l t s . an'd i f it i s maintained i n .…”

Section: -mentioning

confidence: 99%

Chemical Research and Development for Molten-Salt Breeder Reactors.

Grimes¹

1967

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“…Material that had volatilized and condensed on cool portions of the apparatus was shown by X-ray fluorescence analysis to contain arsenic. These results were not unexpected, since thermodynamic data 57 indicate that the reaction 3 Cl-+A s + As£13 +3 e (4) should occur at a potential of 2.9 V vs. the lithium electrode. These data indicate that the charge cutoff potential for lithium/sulfur-arsenic cells should be limited to about 2.85 V to avoid the formation of AsC13• In considering the discharge of a lithium/sulfur-arsenic cell containing excess lithium in the negative electrode, the question arises as to whether additional capacity will be obtained from the reaction of lithium with arsenic after all the sulfur is converted to Li2 S. A Li/LiCl-KCl/As cell was operated at about 400'C to investigate this possibility.…”

Section: Solubility Of Sulfur-bearing Species In Electrolytementioning

confidence: 74%