Ammonium nitrate activation energy

Ammonium nitrate decomposes into nitrous oxide and water. In the solid phase, decomposition begins at about I50°C (302°F) but becomes extensive only above the melting point (I70°C) (338°F). The reaction is first-order, with activation energy about 40 kcal/g mol (72,000 Btii/lb mol). Traces of moisture and Cr lower the decomposition temperature thoroughly dried material has been kept at 300°C (572°F). All oxides of nitrogen, as well as oxygen and nitrogen, have been detected in decompositions of nitrates. 

The reported decomposition of ammonium nitrate indicates that the reaction is unimolecular and that the rate constant has an A factor of 1013 8 and an activation energy of 170kJ/mol. Using this information, determine the critical storage radius at 160°C. Report the calculation so that a plot of rcrit versus T0 can be obtained. Take a temperature range from 80°C to 320°C. 

Thermal decomposition. According to A. J. B. Robertson [12] a very high activation energy, E = 40.5 kcal/mole, characterizes the thermal decomposition of ammonium nitrate. 

Wood and Wise [13] examined the rate of decomposition of ammonium nitrate enclosed in sealed ampoules and kept at temperatures between 200 and 300°C. They found the energy of activation E — 31.4 kcal/mole. 

Cook and A. Taylor [14] as well as Guiochon and L. Jacque [15] used a thermo-gravimetric method to study the decomposition of ammonium nitrate between the temperatures 217-267 and 180-280°C respectively. They found the energy of activation was 38.3 and 36.5 kcal/mole respectively. 

However, Feick and Hainer [18] consider most of the above figures of the energy of activation are not very accurate as in the period prior to explosion a considerable quantity of ammonium nitrate is evaporated. The authors suggest the following equations for ammonium nitrate thermal decomposition ... 

Commercial cold packs work by the same principle. Instead of sodium chloride, however, these packs are made with ammonium nitrate, which absorbs much more energy as it dissolves in water. In order for the pack to be activated, it must be punched. As discussed in Section 9.6, this breaks an inner seal and allows the ammonium nitrate to mix with water. As the ammo-... 

Fuel processing to recover plutonium was an important activity from the earliest days of the atomic energy program. A small pilot plant was built at CRNL in parallel with the construction of NRX. It operated from 1949 to 1953 to extract plutonium from dissolved fuel with triethylene glycol dichloride in a batch process. Ammonium nitrate was the salting-out agent (75). Subsequently, the waste solution from this operation was treated with tributylphosphate (TBP) to remove uranium and residual plutonium, and the ammonium nitrate decomposed before the waste was stored as a concentrated fission product solution. 

Fig. 3 —Current as a function of the reciprocal temperature in the system tetra-/so-pentyl ammonium nitrate/p-azoxyanisole. Note how the activation energy in the nematic range decreases with increasing solute concentration. Compare this variation with the Influence of the orientation (Fig. 2). (Ref. [3])...

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