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Precipitation and Crystallization Processes in Reprocessing, Plutonium Separation, Purification, and Finishing, Chemical Recovery, and Waste Treatment
Published in Reid A. Peterson, Engineering Separations Unit Operations for Nuclear Processing, 2019
Calvin H. Delegard, Reid A. Peterson
The PuF3 precipitation process at SRS employed two sequential batchwise precipitation stages (Orth 1963). The first stage created the initial precipitate from an ~50 g/L Pu(III) feed stream in 4 HNO3 containing 0.2 M NH2SO3H as reductant and 0.3 M hydroxylammonium nitrate (NH2OH ∙ HNO3) as nitrite scavenger. Ascorbic acid was added to the Pu feed to ensure complete reduction to Pu(III) and thus diminish loss to the filtrate occasioned by the precipitation of the more soluble Pu(IV) fluoride hydrate (PuF4 ∙ 2.5H2O).
Analysis of Dispersibility Effect of Carbon Additives on Ignitability of Ammonium-Dinitramide-Based Ionic Liquid Propellants Using Continuous Wave Laser Heating
Published in Combustion Science and Technology, 2022
Such monopropellants with low toxicities are called “green propellants” (Nosseir, Cervone, and Pasini 2021). Several green propellants consist of high energy materials (HEMs) to enhance their performance and achieve high energy densities. Most HEMs are solid and require the use of some solvents for their liquification. Generally, HEMs are liquified using a small volume of water owing to their hygroscopicity. For example, aqueous propellants based on hydroxylammonium nitrate (HAN) (e.g., Hori et al. 2019; Spores, Masse, and Kimbrel 2013) and ammonium dinitramide (ADN) (e.g., Persson et al. 2012; Wingborg 2019) have primarily been investigated across the world. However, although the utilization of HEMs can increase the energy densities of green propellants, the use of a solvent is expected to decrease their combustion temperatures and specific impulses. Therefore, the application of solvents to HEMs might hinder the attainment of high energy densities of green propellants. A solution to this is to use an extremely small amount of solvent, or to apply a liquefaction method without using any solvents
Experimental Investigations of Combustion: (95 WT.-%) HAN–Water Solution with High-SSA Activated Carbons
Published in Combustion Science and Technology, 2019
Meiram K. Atamanov, Rachid Amrousse, Keiichi Hori, Zulkhair Mansurov
According to the experimental studies, the obtained results showed that: The burning rate of HAN (95 wt.-%)–water solution was measured in addition to four types of activated carbon. The burning rates of HAN (95 wt.-%)–water solution have been jumped in the presence of activated carbon CRH-KOH (until rb = 400 mm/s at highest pressures 6 MPa). Also, it was shown that the linear burning rate of HAN may be high, even with low concentration of activated carbon.In the presence of activated carbons, there is observed a dramatic change of decomposition behavior of HAN (95 wt.-%)–water solution in comparison with the thermal decomposition of HAN (95 wt.-%)–water solution alone. The thermal decomposition of hydroxylammonium nitrate (95 wt.-%)–water solution admixed with activated carbon CRH-KOH shown the ability to trigger the decomposition at lower temperatures (86°C versus 185°C) in order to avoid or reduce the use of noble metals in future prospective.The results of EI–MS product ions analysis indicated that the addition of activated carbon allows to reduce significantly the amounts of NOx gases by 30%. With the addition of activated carbon, a double-stage thermal decomposition of pure HAN (95 wt.-%)–water solution becomes single stage with a reduction of decomposition temperature by 40–45°C. The usage of activated carbon additives is economically advantageous because it is a low-cost option.