Hydrazine Nitrate Research Articles

Kinetic model of thermal decomposition of nitric acid solutions of hydrazine nitrate

The kinetic parameters of thermal decomposition of an aqueous solution containing 0.029 mass fractions of hydrazine nitrate and 0.44 mass fractions of nitric acid have been determined: onset temperature and specific thermal effect of exothermic reactions, activation energy, pre-exponential factor, reaction rate and order. Based on the data obtained, a mathematical model of thermal decomposition of nitric acid solutions of hydrazine nitrate has been proposed. It has been found that thermolysis of the solution has a multi-stage nature and can be described by a system of 5 equations of 1st and 2nd order. A comparison of two approaches to creating a mathematical model has been carried out: based on adiabatic calorimetry and differential scanning calorimetry data.

Damage behavior of the surrounding medium caused by different blast-induced dynamic and static loadings

The combination of the dynamic action of explosion stress wave and the static action of explosion gas expansion is what primarily drives rock-breaking blasting, and their different intensities lead to different blasting effects. Therefore, experiments were conducted to explore the damage behaviour of the surrounding medium caused by different blast-induced dynamic and static loadings using digital laser Schlieren and digital laser dynamic caustic systems. The results were as follows: In the air medium, when the explosives detonated, TATP (triacetone triperoxide) had the strongest quasi-static effect, and the highest velocity explosion shock wave and products compared with those of NHN (nickel hydrazine nitrate) and DDNP (diazodinitrophenol). Part of the TATP explosion product was ahead of the shock wave front, whereas for NHN and DDNP, their explosion products were behind the propagation of the shock wave front. The highest pressure peak of TATP was the result of the combined action of the shock wave and explosion product impacting the sensor. In the solid medium, NHN, the explosive with the strongest dynamic load, had the strongest stress wave and highest stress intensity factor peak of the main crack. The velocity reached the peak value at the early stage of propagation, and the dynamic action had a dominant effect on the cracking of the crack; the stronger the dynamic action, the higher the crack initiation energy. The stress intensity factor and propagation rate of the main crack of TATP with the strongest quasi-static effect decreased slower than those of the other explosives; therefore, the main crack propagation time and length were the longest. After cracking, the quasi-static effect dominated the process of crack propagation, where the stronger the quasi-static effect, the longer duration of the driving force of crack propagation. The research results provide a basis for customising explosives for different functions in practical engineering and realising the fine and efficient utilisation of explosion energy.

Effect of acid-treatment on the activated carbon of Ru/AC catalysts for catalytic decomposition of hydroxylamine nitrate and hydrazine nitrate

Two types of 5 %wt Ru/AC catalysts were prepared using carbon carriers treated with 5 mol L−1 HNO3 and 5 mol L−1 HCl by the impregnation method, respectively. The catalysts were characterized by N2 physical adsorption, XRD, XPS, SEM, TEM and ICP-AES. The catalytic activity and stability of the catalysts for the decomposition of hydroxylamine nitrate (HAN) and hydrazine nitrate (HN) was evaluated. The results demonstrated that both catalysts exhibited complete decomposition of HAN and HN under moderate reaction conditions (70–90 ℃), displaying similar activities. And the catalysts treated with hydrochloric acid exhibited better stability and can be reused 128 cycles. Furthermore, the experimental results on various parameters indicate that an increase in temperature and nitric acid concentration leads to a reduction in reaction time. The catalytic performance of Ru/AC catalyst remains unchanged after 20 cycles under radioactive conditions, exhibiting exceptional radiation resistance.

A DFT investigation of hydrazine nitrate dissociation mechanism on MoN(0 0 1)

Hydrazine nitrate (HN) is an important additive for hydrazine-based monopropellant. In this work, density functional theory (DFT) was adopted to calculate the decomposition process of HN components on MoN (001) catalyst surface. Firstly, two stable adsorption configurations of hydrazine nitrate were identified and determined the catalytic decomposition pathway of the thermodynamically favorable configuration. Pathway analysis revealed that the nitric acid group preferentially decomposes in all pathways. Moreover, due to the high activation and desorption energies, H2O molecules are more likely to be generated in the gas phase rather than preferentially adsorbed on the surface. By calculating the activation energies of each elementary reaction, it can be concluded that the cleavage of the NO bond in NO3– with the barrier energy of 0.32 eV plays a decisive role in the decomposition of the HN molecule.

Catalytic decomposition of hydrazine nitrate and hydroxylamine nitrate in radioactive nitric acid waste liquid using Ru/AC catalyst

The 5 wt% Ru/AC catalysts were prepared using the impregnation method.

Nickel hydrazine nitrate/TNT hybrid: toward novel castable energetic nanocomposite with customized performance and decomposition kinetics via novel synergistic effect

Advanced energetic metal–organic frameworks (MOFs) can expose novel characteristics. Highly crystalline nickel hydrazine nitrate (NHN) MOF of 50 nm size was developed via wet coordination. NHN experienced superior decomposition enthalpy of 3100 J g−1 at 222 °C using differential scanning calorimetry. NHN could act as a sensitizer for trinitrotoluene (TNT) and could boost its decomposition enthalpy, detonation velocity, and decomposition kinetics. NHN nanoparticles were effectively integrated into TNT energetic matrix; proper particle dispersion was verified via energy-dispersive X-ray analysis, whereas TNT experienced decomposition enthalpy of 340 J g−1; NHN boosted TNT decomposition enthalpy by 282%, with decrease in main decomposition temperature by 31 °C. NHN/TNT nanocomposite revealed a decrease in TNT activation energy by − 23.5% and − 22% via Kissinger and KAS models, respectively. The synergistic effect of NHN on TNT was ascribed its high decomposition enthalpy, gaseous products. NHN could secure novel catalytic effect on TNT decomposition with increase in detonation velocity by 11%; this was ascribed to the release of active hydrogen that could support CH-α attack with the exclusive formation of nickel nanocatalyst.

The reaction kinetics and mechanism of catalytic decomposition of hydrazine nitrate on Ru/C catalyst in nitric acid solutions

The mechanism and kinetics of the catalytic decomposition of hydrazine nitrate were studied, and proved that the decomposition was a result of two processes.

DFT study on decomposition of hydrazine nitrate on Ir(1 0 0) surface

Hydrazine nitrate (HN) is an efficient additive for hydrazine based monopropellant to decrease the freezing temperature. Density functional theory calculation was carried out to investigate the catalytic decomposition of HN on Ir(100) surface. The most stable molecular structure of HN was identified, while the optimized adsorption configurations of HN on Ir(100) were calculated. Three decomposition pathways over Ir(100) have been found. The scission of N-O bond in HNO3 group happens in all three pathways. When HN is adsorbed by HNO3 group, the N2H4 group exhibits dehydrogenation when at bridge and desorption at top site. The scission of N-N bond can be found when HN is adsorbed by N2H4 group. The rate expressions based on Arrhenius parameters for referred reactions were obtained by transition state theory. Compared with the activation energy of each elementary reaction, the scission of N-O bond in HNO3 group is key to the decomposition rate of HN.

Detailed Kinetic Model for the Thermal Decomposition of Hydrazine Nitrate in Nitric Acid Solution Based on Quantum Chemistry Calculations Combined with the Polarizable Continuum Model.

The decomposition mechanism of hydrazine nitrate in nitric acid solutions was investigated using quantum chemistry calculations combined with the polarizable continuum model at the CBS-QB3//ωB97X-D/SMD level of theory. These calculations provided a detailed kinetic model incorporating rate coefficients and thermodynamic data. Rate coefficients were determined using traditional transition state theory, while diffusion-limited reactions were modeled based on the Einstein-Stokes equations. The resulting model comprised the kinetics for 108 reactions and thermodynamic data for 58 species. This model was validated by comparing simulations of the variations in chemical species during the decomposition process to experimental data acquired under isothermal conditions at 100 °C. The model was found to accurately reproduce the concentration changes of N2H4, HN3, and NH3 and also explained the reaction mechanism. The thermal decomposition was found to proceed via two parallel paths: N2H4 + HNO3 → H2O + HONO + N2H2 and N2H4 + HONO → HN3 + 2H2O. Following these reactions, a portion of the HN3 decomposes to produce NH3 through a multistep process. A sensitivity analysis showed that the rate of decomposition is greatly affected by the pH of the solution.

Thermal stability of nitric acid solutions of reducing agents used in spent nuclear fuel reprocessing

The thermal stability of carbohydrazide, hydrazine nitrate, acetohydroxamic acid in nitric acid solutions has been studied at atmospheric pressure and above atmospheric pressure. The volumes of gaseous products of thermolysis and the maximum rate of gas evolution have been determined at atmospheric pressure. It has been shown that, despite the high rate of gas evolution and large volumes of evolved gases, the conditions for the development of autocatalytic oxidation are not created. Exothermic processes are observed in a closed vessel in the temperature range of 50–250 °C. With an increase in the concentration of nitric acid, the temperatures of the onset of exothermic effects for all mixtures decrease, and the values of the total thermal effects of reactions increase, to the greatest extent for solutions with carbohydrazide.

Catalytic decomposition of hydroxylamine nitrate and hydrazine nitrate using Ru/ZSM-5 catalyst under mild reaction conditions.

Hydroxylamine nitrate and hydrazine nitrate are dangerous explosives and toxic chemicals. Catalytic decomposition is an efficient way for disposal of these chemicals. In the current work, a Ru/ZSM-5 catalyst has been fabricated and evaluated for the decomposition of hydroxylamine nitrate and hydrazine nitrate in 1.0 mol L−1 HNO3. The hydroxylamine nitrate and hydrazine nitrate can be thoroughly decomposed under 80 °C. And the Ru/ZSM-5 catalyst can be separated from the reaction mixture and reused at least 130 times with stable catalytic performance. Easy operation, less solid waste generation, and a simple catalytic device make the strategy reported here practical, environmentally friendly, and economically attractive.

Sonocatalytic recovery of ceria from graphite and inhibition of graphite erosion by ionic liquid based platinum nanocatalyst

Use of ultrasound as an intensified non-destructive decontamination technique for processing graphite limits its reusability beyond a few number of decontamination cycles due to the exfoliation of graphite due to cavitation effects. The current work establishes that the use of platinum nanoparticles in the leachant reduces the erosion of graphite substrate due to cavitation. It presents an improved way of sonochemical recovery of ceria using a mixture of nitric acid, formic acid and hydrazinium nitrate in the presence of platinum nanoparticles and ionic liquid. The platinum nanoparticles catalyst in ionic liquid prevented the generation of the carbon residue due to the combined effect of denitration and reduced sonication. The presence of the catalyst showed a fivefold increase in dissolution kinetics of ceria as well as absence of graphite erosion, facilitating better chances of graphite recycling than the decontamination without the catalyst. The catalytic approach offers a better recycle strategy for graphite with reduced exfoliation and NOx generation due to denitration, making it a more sustainable decontamination process. Since ceria is used as a surrogate for plutonium oxide, the results can be extended to decontaminate such deposits clearly establishing the utility of the presented results in the nuclear industry.

Radiation-thermal stability of hydrazine nitrate in nitric acid solutions

The effect of temperature, HNO3 concentration and radiation dose rate on the decomposition of hydrazine nitrate in aqueous nitric acid solutions has been studied. Kinetic characteristics have been obtained for evaluating the yields of the main decomposition products of hydrazine nitrate - hydrazoic acid and ammonium nitrate. The results of the study are important for analyzing the explosion safety of technological processes with nitric acid solutions containing hydrazine nitrate.

Energetic water compositions as rocket propellants

New results of experimental and theoretical research of ignition and combustion of energetic water compositions used as environmentally safe (green) propellants for rocket and other internal combustion engines are presented. The theoretical assessment of the thermodynamic effect of water additives to fuels depending on the characteristics of the main energetic material and the amount of water additives is performed. The characteristic features of the temperature regimes of ignition and combustion of single droplets of water solutions of energetic materials (for example, solutions of hydrazine nitrate and sodium azide), as well as the combustion of single aluminum droplets in mixtures of water vapor with nitrogen at different ambient temperatures and nitrogen content. A theoretical model for the burning of droplets of energetic intensive aqueous solutions, suspensions, and emulsions is formulated. The formula for the drop burning time is based on the experimental data obtained. Dedicated to: Konstantin E. Tsiolkovsky, the founder of Astronautics.

Catalytic reduction of U(VI) with hydrazine using Pt/SiO2 catalyst in nitric acid medium—kinetics and equilibrium

Kinetics of catalytic reduction of uranyl species, U(VI) to U(IV) with hydrazine nitrate was studied over Pt/SiO2 catalyst in nitric acid medium. Experiments were carried out in a stainless-steel autoclave as a function of mixing intensity, temperature, catalyst loading and concentration of nitric acid, hydrazine and uranium. Langmuir–Hinshelwood approach was considered to derive various model equations and each of them was evaluated. Results of the present study indicated that catalytic reduction of U(VI) can be described by surface reaction between adsorbed molecules. The activation energy of the reaction was calculated to be 74.5 kJ/mol, suggesting a chemical reaction controlled process.

Pulse radiolysis study on the reactivity of NO3˙ radical toward uranous(iv), hydrazinium nitrate and hydroxyl ammonium nitrate at room temperature and at 45 °C.

Concentrated nitric acid solutions subjected to radiation produce radicals of extreme importance in the reprocessing of spent nuclear fuel. Knowledge of the different rate constants of the reactions involved in this chemistry is needed to improve the efficiency of the process and to define safe operating practices. Pulse radiolysis measurements are performed to find the rate constant of the reaction between NO3˙ radicals and U(iv) in highly concentrated nitrate solution. The optimal stabilization conditions toward thermal oxidation are defined for the considered solutions at room temperature and at 45 °C by adding anti-nitrous agents such as hydrazinium nitrate (HN) and hydroxyl ammonium nitrate (HAN). The decay of the NO3˙ radical is monitored and its reaction rates with HN, HAN and U(iv) are found to be 1.3 × 105, 1.5 × 107 and 1.6 × 106 M-1 s-1 at room temperature. The latter value is more than 10 times lower than the one currently used in numerical codes for simulation of the long-term radiolytic degradation associated with the reprocessing and storage of spent nuclear waste. At 45 °C, conditions similar to the reprocessing of spent fuel, the values of the rate constants of NO3˙ radical toward HN, HAN and U(iv) increase and are found to be 2.6 × 105, 2.9 × 107 and 9.3 × 106 M-1 s-1.

Thermal Stability of Nitric Acid Solutions of Hydrazine Nitrate

Thermal stability of hydrazine nitrate (HN) in solutions in 4–12 M HNO3 in the temperature interval 70–150°C was studied. Exothermic reactions accompanied by gas evolution arise in such systems under definite conditions. The intensity of such reactions depends on the component concentrations and temperature. The characteristics of the exothermic processes were determined to evaluate the explosion safety of process operations. Because of sharp pressure buildup in apparatuses, exothermic processes in the course of evaporation of HN-containing nitric acid solutions are hazardous from the viewpoint of radiation accidents.

OZM Ball Drop Impact Tester (BIT‐132) vs. BAM Standard Method – a Comparative Investigation

AbstractSafety, performance, cost efficient synthesis and toxicity are the most important aspects of modern explosives. Sensitivity measurements are performed in accordance with different protocols all around the world. Sometimes the BAM drop hammer does not accurately reflect the sensitivity of an energetic material, in particular the sensitivity of primary explosives. Therefore, we present here preliminary results obtained using the novel ball drop tester (BIT‐132), manufactured by OZM research, following MIL‐STD‐1751 A (method 1016). The ball drop impact sensitivity tester is a device in which a free‐falling steel ball is dropped onto an unconfined sample, and is expected to produce more realistic results than the currently commonly used BAM method. The results obtained using the probit analysis were compared to those from the BAM drop hammer and friction tester. The following sensitive explosives were investigated: HMTD, TATP, TAT, Tetrazene, MTX‐1, KDNBF, KDNP, K2DNABT, Lead Styphnate Monohydrate, DBX‐1, Nickel(II) Hydrazine Nitrate, Silver Acetylide, AgN3, Pb(N3)2 RD‐1333, AgCNO, and Hg(CNO)2.

Development and Pilot Testing of New Flow Diagrams for Plutonium Purification at the RT-1 Plant

To modernize the extraction facility of the RT-1 plant, two flow diagrams for plutonium purification have been developed. In the first flow diagram, the Pu(IV)–Np(IV) valence pair is stabilized and both Pu and Np are stripped and, in the second flow diagram, the Pu(IV)–Np(V) valence pair is stabilized and only Pu is stripped. The problem of stabilizing the pair of the desired components in the required valence state is solved using reagents that had already been used at the RT-1 plant: hydrogen peroxide, hydrazine nitrate, and a catalyst (Fe). Both flow diagrams are adapted to the extraction facility of the plant with minimum changes in equipment and successfully pass extended process tests. As the result of this work, the volume and salt content of the raffinate are reduced.

Isolation of Plutonium in the Course of REE/TPE Separation by Displacement Complexing Chromatography

Isolation of Pu from a TPE/REE mixture by displacement complexing chromatography on KU-2 cation-exchange resin was studied. To stabilize Pu in the trivalent state, the sorption of the mixture components from the initial solutions was performed in the presence of hydrazine nitrate. To convert Pu to the tetravalent state, H2O2 was added to the DTPA solution used as an eluent. The influence of temperature and H2O2 concentration on the chromatographic isolation of Pu was studied. Optimum conditions were found for separating Pu from TPE and REE.