Thermal decomposition in alkali metal nitrate melts

Kust, Roger N.; Burke, J.D.

doi:10.1016/0020-1650(70)80243-4

Cited by 69 publications

(28 citation statements)

References 7 publications

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“…At higher temperatures the equilibrium is generally reached faster compared to lower temperatures. The reported periods range from days at a temperature of around 300 • C [13] to tens of minutes at a temperature of about 700 • C [11].…”

Section: Intermediate Temperature Region (450 • C To 550 • C)mentioning

confidence: 97%

“…The nitrite ion concentration was reported to reach almost equilibrium within (7 to 16) h at temperatures between 295 • C and 340 • C. Although there is some uncertainty about the exact measurement conditions, these data have been converted to the molar ratio NO 2 − /NO 3 at a partial pressure of p o2 = 0.21 ( Fig. 4) [13]. In order to improve the data basis for the thermal stability of NaNO 3 in the low-temperature region, long-duration tests of NaNO 3 at 350 • C were performed.…”

Section: Thermal Stability Of Nano and Nitrite Formationmentioning

confidence: 99%

“…It is well known that molten nitrates decompose to nitrites in the intermediate temperature region from about 450 • C to 550 • C. The thermal dissociation is reversible, and the equilibrium reaction can be written for NaNO 3 as [8,[11][12][13][14][15][16] NaNO 3(l) ↔ NaNO 2(l) + 1/2 O 2(g) (1) Kinetic data of the oxidation and decomposition of different alkali metal nitrates have been reported. They include KNO 3 /KNO 2 [10][11][12]15], KNO 3 -NaNO 3 /KNO 2 -NaNO 2 [8,12], and NaNO 3 /NaNO 2 [12,15].…”

Section: Intermediate Temperature Region (450 • C To 550 • C)mentioning

confidence: 99%

“…The thermal decomposition of NaNO 3 can be divided into three characteristic regions [10][11][12][13][14][15][16] Literature about the low-temperature region (T m to 450 • C) is generally limited. Kust reported about experiments of the eutectic KNO 3 -NaNO 3 with T m = 222 • C. They found small amounts of nitrites at temperatures as low as 295 • C in the melt.…”

Section: Thermal Stability Of Nano and Nitrite Formationmentioning

confidence: 99%

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Characterization of Sodium Nitrate as Phase Change Material

2011

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In this article the results of material investigations of sodium nitrate (NaNO 3 ) with a melting temperature of 306 • C as a phase change material (PCM) are presented. The thermal stability was examined by kinetic experiments and longduration oven tests. In these experiments the nitrite formation was monitored. Although some nitrite formation in the melt was detected, results show that the thermal stability of NaNO 3 is sufficient for PCM applications. Various measurements of thermophysical properties of NaNO 3 are reported. These properties include the thermal diffusivity by the laser-flash, the thermal conductivity by the transient hot wire, and the heat capacity by the differential scanning calorimeter method. The current measurements and literature values are compared. In this article comprehensive temperature-dependent thermophysical values of the density, heat capacity, thermal diffusivity, and thermal conductivity in the liquid and solid phases are reported.

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Section: Intermediate Temperature Region (450 • C To 550 • C)mentioning

confidence: 97%

Section: Thermal Stability Of Nano and Nitrite Formationmentioning

confidence: 99%

Section: Intermediate Temperature Region (450 • C To 550 • C)mentioning

confidence: 99%

Section: Thermal Stability Of Nano and Nitrite Formationmentioning

confidence: 99%

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Characterization of Sodium Nitrate as Phase Change Material

2011

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“…Melting occurs at 579 K and requires 182.4 J/g. Slow decomposition begins at about 875 K, and the pseudoequilibrium between the nitrate, nitrite, and oxygen has been examined over many years (Oza 1945, Freeman 1956, Sirotkin 1959, Arvia et al 1964, Bond and Jacobs 1966, Kust and Burke 1970. Many investigations of these reactions appear in the literature and include spectroscopic measurements of melts, gas analysis, and electrochemical measurements.…”

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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Nitrates and Nitrites

Laue

Thiemann

Scheibler

et al. 2000

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Sodium Nitrate 1.1. Properties 1.2. Occurrence 1.3. Production 1.3.1. Chile Saltpeter 1.3.2. Synthetic Sodium Nitrate 1.4. Product Forms, Storage, and Transportation 1.5. Uses 1.6. Economic Aspects 2. Potassium Nitrate 2.1. Properties 2.2. Occurrence 2.3. Production 2.3.1. Bacterial Production of Saltpeter 2.3.2. Converted Saltpeter 2.3.3. Potassium Nitrate from Calcium Nitrate 2.3.4. Potassium Nitrate from Ammonium Nitrate 2.3.5. Potassium Nitrate from Potassium Chloride and Nitric Acid 2.4. Product Forms, Storage, and Transportation 2.5. Uses 2.6. Economic Aspects 3. Calcium Nitrate 3.1. Properties 3.2. Occurrence 3.3. Production 3.3.1. Calcium Nitrate from Limestoneand Nitric Acid 3.3.2. Calcium Nitrate as a Byproduct of the Odda Process 3.4. Product Forms, Storage, and Transportation 3.5. Uses 3.6. Economic Aspects 4. Sodium Nitrite 4.1. Properties 4.2. Production 4.3. Product Forms, Storage, and Transportation 4.4. Uses 4.5. Economic Aspects 5. Potassium Nitrite 5.1. Properties 5.2. Production 5.3. Uses 6. Ammonium Nitrite 6.1. Properties 6.2. Production 6.3. Uses 7. Calcium Nitrite 7.1. Properties 7.2. Production 7.3. Uses 8. Analysis of Nitrates and Nitrites 9. Environmental Aspects 10. Toxicology and Occupational Health

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Thermal decomposition in alkali metal nitrate melts

Cited by 69 publications

References 7 publications

Characterization of Sodium Nitrate as Phase Change Material

Characterization of Sodium Nitrate as Phase Change Material

Calculation of reaction energies and adiabatic temperatures for waste tank reactions

Nitrates and Nitrites

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