Thermal Decomposition Of Ammonium Nitrate Research Articles

NiCoCr2O4 as a potential catalyst for the thermal decomposition of ammonium nitrate: a kinetic investigation

The thermal decomposition of high energetic materials plays an important role in their thermal performance. Use of the catalyst is one of the efficient ways improve the thermal performance of the high energetic materials. Therefore, in this work nickel cobalt chromite (NiCoCr2O4) prepared using precipitation approach was utilized as a catalyst for decreasing the thermal decomposition temperature and activation energy of high energetic material ammonium nitrate (AN). The results suggest that AN/NiCoCr2O4 decomposes at lower temperature (240 °C) within a short temperature range (Thermo gravimetry decomposition curve = 180–250 °C). The kinetic study was investigated using Kissinger-Akahira-Sunose (KAS) and Kissinger method (5, 10, and 15 °C min−1 heating rates). The activation energy of AN was reduced from 158.0 to 141.5 kJ mol−1 and decrease in the pre-exponential factor was observed upon addition of NiCoCr2O4. The outcome of the present work can be used to design AN based high energetic formulations containing NiCoCr2O4 catalyst with better thermal decomposition performance.

Investigating the Catalytic Effect of a Zeolitic Imidazolate Framework, ZIF-8, on the Phase Transition and Thermal Decomposition of Ammonium Nitrate

Investigating the Catalytic Effect of a Zeolitic Imidazolate Framework, ZIF-8, on the Phase Transition and Thermal Decomposition of Ammonium Nitrate

Nitrogen‐doped reduced graphene oxide/Fe2O3 hybrid as efficient catalyst for ammonium nitrate

AbstractIn this investigation, we successfully synthesized a hybrid material, N‐rGO@Fe2O3, via a one‐step hydrothermal process, comprising nitrogen‐doped reduced graphene oxide and α‐Fe2O3. Thorough characterization using diverse analytical methods validated its structure. Employing this hybrid composite as a catalyst, we studied its efficacy in the catalytic thermal decomposition of ammonium nitrate (AN). The N‐rGO@Fe2O3/AN composite was prepared using a recurrent spray coating method with 3 % mass of the hybrid material. Thermo‐gravimetric (TG) and differential scanning calorimetric (DSC) analyses were employed to investigate the catalytic effect. Computational assessment of Arrhenius parameters was conducted through isoconversional kinetic approaches. Results from the kinetic analysis allowed the determination of the critical ignition temperature. Furthermore, calorific values for pure AN and N‐rGO@Fe2O3/AN were measured using an oxygen calorimetric bombe, revealing a 41 % reduction in activation energy barrier and a lowering of the critical ignition temperature from 292 °C to 283 °C upon incorporation of the hybrid material. Notably, the surface modification of AN with N‐rGO@Fe2O3 resulted in an increase of 1440 J/g in the observed calorific values. These findings highlight the potential of N‐rGO@Fe2O3 as an effective catalyst, offering promising implications for applications in enhancing ammonium nitrate thermal decomposition.

Nitrous oxide as diazo transfer reagent.

Nitrous oxide, commonly known as "laughing gas", is formed as a by-product in several industrial processes. It is also readily available by thermal decomposition of ammonium nitrate. Traditionally, the chemical valorization of N2O is achieved via oxidation chemistry, where N2O acts as a selective oxygen atom transfer reagent. Recent results have shown that N2O can also function as an efficient diazo transfer reagent. Synthetically useful methods for synthesizing triazenes, N-heterocycles, and azo- or diazo compounds were developed. This review article summarizes significant advancements in this emerging field.

Analysis of the thermal decomposition of munitions wastewater

AbstractThe thermal decomposition of ammonium nitrate (AN) laden munitions wastewater and comparable control samples were studied under air and nitrogen environments at pressures from 0.1 MPa to 10 MPa. The decomposition enthalpies, measured using a Differential Scanning Calorimeter (DSC), and gaseous emissions, measured using a Fourier‐Transform Infrared Spectrometer (FTIR), were used to evaluate the quality of decomposition. Experiments demonstrated that higher pressures improved the energy yield and reduced the quantities of harmful from the decomposition of all samples. At 10 MPa, experimentally measured decomposition enthalpy from the munitions wastewater was 1.8 MJ/kg, approximately 45 % of its standard enthalpy of decomposition, and NO and accounted for only 0.7 % and 0.08 % of the nitrogen in the sample, respectively. The emissions stream from the wastewater was found to primarily consist of , , and . An analysis of the heat releases and the emissions showed that higher pressures improved the extent and enthalpy of decomposition by preventing premature loss of gaseous intermediates and sensible heat through the pin‐hole crucibles used in the experiments. Moreover, high pressures precluded the evaporation of water and promoted the decomposition of AN via a radical mechanism.

Nanostructured Al-doped maghemite: A low-cost and eco-friendly material tested for methylene blue removal from water and as an accelerator in ammonium nitrate decomposition

Maghemite's properties for roles as removable and reusable catalysts or photocatalysts in reactions that promote green chemistry can be enhanced by doping with other metals. We investigated nanostructured aluminum-doped magnetic iron(III) oxides (AlxFe2-xO3, x = 0.33, 0.67, and 1) synthesized via the autocombustion method and characterized using various techniques. These materials were tested as photocatalysts for methylene blue dye degradation without peroxide and as catalysts for the thermal decomposition of ammonium nitrate. The results revealed that the cubic spinel structure predominates in all compositions. Aluminum doping led to decreased cell parameters and grain size and loss of microgranular structure. Saturation magnetization decreased with aluminum doping, reaching a low value (∼2 emu/g) for x = 1. The optical band gaps were red-shifted with respect to pure maghemite, with values near 2 eV. Among compositions, x = 0.33 showed the best photocatalytic efficiency, closely matching incident light energy (1.95 eV). The highest degradation efficiency was around 37 % after 80 min. The catalytic effect on ammonium nitrate decomposition was strongly correlated with aluminum concentration, turning the reaction exothermic with energy release of 200 and 400 J/g for x = 0.33 and 0.67, respectively.

Extraction of humic acid from peat and lignite and the thermal behavior of their mixtures with ammonium nitrate

Due to the positive effect on soil structure and the influence on improving the efficiency of plant roots nutrient uptake, humic acids (HA) are widely considered for fertilizer production. Especially, it seems to be particularly promising to use them as additives in technologies of mineral fertilizer production. One of the common mineral fertilizer components, due to its good water solubility and the presence of nitrogen in two forms, is ammonium nitrate (AN). The aim of this study was to determine the influence of the humic acids extracted from peat and lignite on the thermal decomposition of HA and the thermal decomposition of ammonium nitrate and humic acids mixtures. For the quality assessment of HA, spectroscopic methods (FTIR/ATR and CP/MAS 13C NMR) and analysis of elemental composition were used. The analysis of the spectra showed differences in the degree of humification of humic acids extracted from various raw materials. HA isolated from peat were distinguished by the presence of peptides, polysaccharides, and lignin residues. Elemental analysis showed the higher carbon and sulfur content in the extracted HA compared to the reference samples. The results of the TG-DTA-MS analysis confirmed the influence of differences in the molecular structure of humic acids, especially in the aliphatic and aromatic carbon content, on the thermal decomposition process. Total content of carboxylic and/or hydroxylic functional groups had a significant impact on the start of the decomposition temperature. Their increase visibly influenced the acceleration of the exothermic decomposition of AN.

Effects of urea on the thermal decomposition behavior of ammonium nitrate: A reliable thermal safety performance enhancer

To address the actual disaster of thermal decomposition and explosion of ammonium nitrate (AN), a commonly used raw material, urea was selected as an additive to study its effect on the thermal decomposition of AN through experimental and theoretical methods. The thermal decomposition kinetics, energy release, self-reaction properties of adiabatic environments, and escaping gaseous products have all been discussed. It was found that urea has an inhibitory effect on the crystalline transformation of AN stored at room temperature, which is beneficial to its thermal safety. The results showed that urea increased the activation energy of the thermal decomposition of AN, raised the temperature of the initial reaction and reduced heat generation. Furthermore, the action mechanism of urea is suggested to be heat absorption by its thermal decomposition and the escape of ammonia. Finally, the study carried out an engineering assessment of the thermal safety of AN under the action of urea and found that the addition of urea greatly enhanced the thermal safety performance of stored and transported AN. The comprehensive analysis concluded that a small dose of urea could be added to enhance the thermal stability of AN without affecting its normal function.

Comparative study of the thermal decomposition of ammonium nitrate in the presence of nanocrystalline copper ferrite

This study aims to investigate the catalytic effects of nanocrystalline copper ferrite (CF) on the thermal decomposition of ammonium nitrate.

Catalytic performance of nano-sized cobalt copper ferrite on thermal decomposition of ammonium nitrate

Ammonium nitrate (AN) is being explored as a high energetic oxidizer in propellants. The utilization of pure AN in propellants suffers from a low burning rate. To improve the burning rate, it is important to improve the thermal decomposition characteristics of AN to fasten its thermal decomposition. The effect of CoCuFe2O4 additive was explored to improve the thermos-kinetic parameters of AN's thermal decomposition. Coprecipitation was used to synthesize nanocrystalline CoCuFe2O4. The thermodynamic and kinetic parameters of decomposition of AN: CoCuFe2O4 were investigated using TG-DSC-DTA analysis at 5, 10, and 15 °C min−1. The thermodynamic and kinetic studies suggest that the thermal decomposition of AN+CoCuFe2O4 was more favorable than AN. The decomposition of AN+CoCuFe2O4 occurs at a lower 10 °C lower temperature with ∼44 % decrement in the activation energy and decreased pre-exponential factor. The faster decomposition at a lower temperature was obtained for AN+CoCuFe2O4 composition. Nano-sized particles with efficient optical and polarizable properties made this ferrite material easily separable and eco-friendly for the preparation of a chemical propulsion system based on AN. The AN+CoCuFe2O4 propulsion mixture can be utilized in place of pure AN for better thermal performance in a propellant system.•CoCuFe2O4 was able to influence the thermal decomposition parameters of ammonium nitrate (AN).•AN+CoCuFe2O4 decomposes at lower activation energy with a faster decomposition than pure AN.•Thermodynamics suggest favorable decomposition of AN+CoCuFe2O4 than pure AN.

An Efficient Nanocatalyst Cobalt Copper Zinc Ferrite for the Thermolysis of Ammonium Nitrate.

This work reports synthesis and catalytic effect of cobalt copper zinc ferrite (CoCuZnFe2O4) on the thermal decomposition of ammonium nitrate (AN). AN is a crystalline hygroscopic powder widely applicable as an oxidizer in the propellant formulations for high energetic materials but requires improvement in its thermal decomposition characteristics. Nanocatalyst spinel ferrite CoCuZnFe2O4 was prepared using the coprecipitation method and characterized by various physicochemical instrumental techniques like XRD, FE-SEM, UV-vis, Raman, and TG-DSC. Catalytic study of AN in the presence of nano-CoCuZnFe2O4 was investigated using DSC analysis. The Raman and XRD study confirm the formation of ferrite with a crystalline size 9-22 nm. TG suggests that the catalyst was thermally stable up to 400 °C with ∼10% mass loss. The UV-vis study shows that the optical band gap energy of CoCuZnFe2O4 was 2.6 eV, which may help in fast acceleration of electrons during thermolysis of AN, making the thermal decomposition of AN more favorable in the presence of CoCuZnFe2O4. The thermal decomposition investigation suggests that the activation energy of AN thermolysis in the presence of 2 wt % CoCuZnFe2O4 was decreased by ∼37%. It is concluded that CoCuZnFe2O4 can be used as an efficient catalyst for improving AN's thermal characteristics.

Variations in gaseous nitric acid concentrations at Tottori, Japan: Long-range transport from the Asian continent and local production

To evaluate factors affecting variation in gaseous nitric acid (HNO3) concentrations, including long-range transport from the Asian continent, we conducted continuous observations of HNO3 and related species from April 2016 to October 2017 in a coastal region near Tottori, Japan. HNO3 concentrations and concentration ratios of HNO3 to total odd nitrogen species (HNO3/NOy) during sea-breeze periods exhibited similar seasonal variations, with maximum concentrations during spring–summer and minimum concentrations during autumn–winter. The sea-breeze period concentrations were higher than those during land-breeze periods in spring–summer. Similar diurnal variations for HNO3 concentrations and HNO3/NOy with maximum values occurring during the daytime and minimum values during the nighttime were observed regardless of the season. These seasonal and diurnal variations were attributed to the reaction of NO2 with OH radicals and/or the thermal decomposition of ammonium nitrate (NH4NO3) aerosols. In terms of long-range transport from the Asian continent, a thermal equilibrium of HNO3 and gaseous ammonia (NH3) with NH4NO3 can affect variation of the HNO3 concentration. A chemical thermodynamics evaluation was conducted of the equilibrium of HNO3 and gaseous ammonia with NH4NO3. The concentration of extra ammonium ions was determined by taking into consideration that required for full neutralization of non-sea-salt sulfate in formation of ammonium sulfate, and seasonal variation in the results was evaluated. The results suggested that a thermal equilibrium of HNO3 and NH3 with NH4NO3 transported from the Asian continent could contribute to concentration variations of HNO3 in seasons other than summer.

Experimental and theoretical study of the effect of typical halides on thermal decomposition products and energy release of ammonium nitrate based on microcalorimetry and FTIR

Ammonium nitrate (AN) is widely used as a raw material in industry and agriculture. However, the Beirut explosion in Lebanon once again shows that AN has a risk of thermal runaway during storage, especially long-term storage or when some possible substances are mixed therein. This paper focuses on the effect of halides additives, such as sodium fluoride, sodium chloride, sodium bromide and sodium iodide, on the thermal decomposition products and energy release of AN. Especially, the thermal decomposition of AN added with 5% sodium halide and the evolved gases in the thermal decomposition process are investigated by C80 microcalorimetry and FTIR. The results show that all kinds of sodium halides have an effect on the thermal decomposition of AN, although these effects are different. The addition of the halide not only changes the timing of the formation of the AN thermal decomposition characteristic product, but also reduces the heat of the reaction. Combined with optimized kinetic parameters, the engineering prediction of thermal safety was carried out for each type of sample. It is found that sodium iodide is beneficial to the safety of large-scale storage of AN. The research results can provide a reference and guidance for revealing the thermal decomposition mechanism of halide-containing AN and thermal decomposition simulation of AN with additives.

Catalytic effect of lithium titanate oxide doped with praseodymium on thermal decomposition of ammonium nitrate

In this work, lithium titanate oxide (Li4Ti5O12) (LTO) and praseodymium ion doped in lithium titanate oxide (Pr-LTO) were synthesized in a sol–gel simple method, and their catalytic effects on thermal decomposition of ammonium nitrate were reported using thermogravimetric analysis–differential scanning calorimetry (TGA–DSC) techniques. The X-ray powder diffraction, Brunauer–Emmett–Teller surface area measurements, particle size analysis, energy-dispersive X-ray spectroscopy, and scanning electron microscopy techniques were used to identify the structural properties and morphology of LTO and Pr-doped LTO. By doping the praseodymium ion within the LTO spinel structure, the surface area increases (from 204.2 m2 g−1 for LTO semiconductor to 318.9 m2 g−1 for Pr-doped LTO), and the catalytic activity improved. The catalytic effects of LTO and Pr-LTO on the thermal behavior of AN were studied via TG-DSC techniques. The thermal decomposition of pure AN (196–400 °C) shifted to lower temperatures, 154–280 °C, and 131–241 °C, in the presence of LTO and Pr-LTO, respectively. The results showed that the catalytic effects of LTO were improved by praseodymium doping. The Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), Starink, and Tang methods were used to determine activation energies of all AN samples at different conversion values (α). The activation energies of pure AN values were 166 ± 3, 166 ± 2, 166 ± 2, and 162 ± 2 kJ mol−1, while AN/LTO activation energies were 145 ± 2, 144 ± 1, 144 ± 1, and 144 ± 2 kJ mol−1 and finally, those of AN/Pr-LTO were 112 ± 1, 109 ± 2, 110 ± 1, and 110 ± 1 kJ mol−1 using FWO, KAS, Starink, and Tang methods, respectively.

Safer emulsion explosives resulting from NOx inhibition

Ammonium nitrate (NH4NO3, AN) is a major commodity chemical. Its principal uses are as a fertilizer and an explosive. Ammonium nitrate is inherently unstable and has been the cause of numerous accidental explosions, sometimes with hundreds of deaths. We have investigated the thermal decomposition and methods of inhibiting the critical reactions of ammonium nitrate. NOx gas was shown to accumulate during an induction period and lead to the generation of nitrous acid (HNO2). Removal of NOx by adsorption or reduction provides alternative approaches to inhibition. In this work we reveal alternative methods to inhibit accidental ammonium nitrate explosions. Layered double hydroxides, such as hydrotalcite, were found to be very effective at inhibiting and delaying detonation by adsorbing NOx. Urea, traditionally used to inhibit explosions, was found to be very ineffective at higher temperatures (above ∼ 80 °C). However, the addition of MnO2 catalysts to urea increased its efficiency at temperatures up to ∼ 130 °C. The urea/MnO2 catalyst system was a highly effective inhibitor for preventing thermal decomposition of ammonium nitrate over a wide temperature range.

Thermal decomposition of ammonium nitrate on rust surface: Risk of low-temperature fire

Ammonium nitrate (AN, NH4NO3) remains classified as an oxidising agent for transport, storage and handling purposes. The safe use of ammonium nitrate requires strict procedures as AN is incompatible with many materials. This study investigates the thermal decomposition of AN on surfaces of rust, potentially present on steel in storage facilities of AN. Infrared spectroscopy and X-ray diffraction served to characterise the mineralogy of the rust, relatively to neat iron (III) oxide. Furthermore, simultaneous thermogravimetric measurements and differential scanning calorimetry afforded the isoconversional analysis that yields the activation energies of the decomposition process. The results, in conjunction with the molecular modelling involving oxygen-deficient Fe2O3 clusters, elucidate the effect of rusts, existing on the surface of corroded steel, in reducing the ignition temperature of AN. This process manifests itself by lowering the activation energies of the initiation channels of the decomposition reactions. On the contrary, pure Fe2O3 does not influence the decomposition of AN. The dehydroxylation of hydrated iron (III) oxide, present on surfaces of rust, exposes the Fe sites that react exothermically with AN, before the material assumes the ordered Fe2O3 phase.

Thermal decomposition of ammonium nitrate

SummaryThe thermal decomposition reactions of ammonium nitrate (AN) are reviewed. Both neat AN and AN containing various contaminants are examined, however quantitative kinetics results are not encompassed. Also not included is the performance of AN as the oxidizer in rocket propellants or in explosives such as ANFO. The review is intended to be the most comprehensive review of decomposition reactions of AN since Berthelot's treatise of 1892. Despite hundreds of papers on the topic that have appeared in the intervening years, understanding of decomposition mechanisms remains only modestly more complete than it was in Berthelot's day. However, some additional reaction steps and mechanisms have been identified and these are discussed. Explosions of AN most commonly involve fire as the proximate cause, yet chemical‐mechanism research on the topic is nil. A modest number of studies have explored the potentiation of AN decomposition by organic contaminants. These have, thus far, not produced guidance useful for promoting of safety from fire‐related causes. Contamination from inorganic sources, notably chlorides is better understood and some mechanisms have been studied. The UN classification of AN as an oxidizer, instead of as an explosive, should not be interpreted literally, since AN has been associated with numerous detonation disasters.

Effect of the NH4NO3 Addition on the Low-T NH3-SCR Performances of Individual and Combined Fe- and Cu-Zeolite Catalysts

We have measured NOx conversions and N2O productions over Fe-BEA and Cu-SAPO catalysts and over their sequential arrangements under Enhanced SCR conditions, resulting from the addition of an aqueous solution of ammonium nitrate (AN) to the typical Standard SCR feed stream, and we have compared them to those observed under Standard and Fast SCR conditions. The expected strong enhancement of the poor low temperature activity of the Fe-BEA catalyst was confirmed: both NH3 and NOx conversions and N2O formations similar to those of the Fast SCR reaction were achieved when cofeeding ammonium nitrate. On the other hand, the Cu-SAPO efficiency was drastically decreased by the addition of AN at low temperatures, possibly due to trapping of the ammonium nitrate salt within the SAPO zeolite, characterized by smaller pores than those of the BEA zeolite. The Cu-SAPO performances were recovered only at T > 250 °C with a huge release of N2O due to the thermal decomposition of AN. The combined system with the Fe-zeolite sample placed upstream of the Cu-zeolite also exhibited outstanding low temperature deNOx performances, with even lower N2O production than over the Fe-zeolite only at the same Enhanced SCR (E-SCR) conditions.

The influence of nanoxide additives on the characteristics of thermal decomposition of ammonium nitrate

Thermal decomposition of ammonium nitrate (NH4NO3) containing 5% (by weight) of catalytic additives in the form of metal oxides (NiO, CuO, Co2O3) has been studied. The experiment was performed by thermogravimetric analysis at a heating rate of 5°C/min to a maximum temperature of 800°C in argon atmosphere. Based on the results of DTA, physical and kinetic characteristics of thermal decomposition we analytically assessed. The addition of catalytic agents was found to lead to a decrease of onset temperature of active NH4NO3 decomposition, which promotes the reaction shift to the low-temperature region. The effect of the initiation additive manifested in a significant reduction of sample residence time within preheating stage (Δti = 5.2 min). In presence of catalytic additives the total time of thermal decomposition tf was found to decrease. The greatest change of Δtf (2.8 minutes) was recorded for the sample modified by addition of Co3O4. The maximum decrease of the average activation energy (for decomposition of 5%Co3O4/NH4NO3) was 14.2 kJ/mol.

An experimental and theoretical study of optimized selection and model reconstruction for ammonium nitrate pyrolysis.

Ammonium nitrate (AN) is a commonly-used industrial raw material in industrial explosives and fertilizers areas. However, as an energetic material, its danger exists during the production, transportation, and storage, resulting in a large number of accidents involving personal injury and property loss. To obtain the accurate kinetic triplet parameters of AN thermal decomposition, a series of thermogravimetry analysis (TGA) experiments was conducted with four different heating rates. Activation energies were calculated by different isoconversional methods Then the kinetic triplet of AN pyrolysis was optimized using a combination of experimental and simulant methods. Combined with the traditional model-free and model-fitting approaches, the experimental kinetic model for AN pyrolysis was optimized and then reconstructed. Through the pyrolysis reaction of AN, a reliable methodology for processing TGA data of hazardous material is proposed in the paper, and the kinetic parameters can be accurately obtained by using such a kinetics method.