Evaporation Crystallization of RDX by Ultrasonic Spray

Kim, Junwoo; Shin, Moon-Soo; Kim, Jae-Kyeong; Kim, Hyoun-Soo; Koo, Kee-Kahb

doi:10.1021/ie201314r

Cited by 36 publications

(30 citation statements)

References 51 publications

(78 reference statements)

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“…c) at a cooling rate of 70 °C per hour. PXRD patterns of all samples matched well with that of α ‐RDX . Furthermore, it was confirmed that PVP and spherical agglomeration have no influence on the crystal structure of RDX.…”

Section: Resultssupporting

confidence: 58%

Formation of Spherical Agglomerates in Cooling Crystallization of Hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine

Lee

Kim

et al. 2017

Chem Eng & Technol

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The production of spherical agglomerates of hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX) from acetone by cooling crystallization with poly(vinylpyrrolidone) (PVP) is described. It was found that PVP suppresses the nucleation of RDX at the initial stage, but tremendous nucleation of RDX occurred abruptly after the induction period. The rapid nucleation may be associated with the primary nucleation due to the presence of PVP. It can be concluded that the addition of PVP results in the formation of RDX particles with sufficient number density for spherical agglomeration. It was found that such spherical agglomeration propagates very rapidly after nucleation within one minute and the size of spherical agglomerates is affected by the cooling rate.

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Section: Resultssupporting

confidence: 58%

Formation of Spherical Agglomerates in Cooling Crystallization of Hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine

Lee

Kim

et al. 2017

Chem Eng & Technol

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“…The importance of improving the crystal morphology can be highlighted by its ability to increase the specific impulse by 30% to 50% [12]. Successful modification of RDX crystal morphology by ultrasound was previously reported [9,13], but not for ADN. It is known that ultrasound treatment can induce oxidation reactions for many substrates, as reported in [14,15].…”

Section: Introductionmentioning

confidence: 99%

Prilling and Coating of Ammonium Dinitramide (ADN) Solid Green Propellant in Toluene Mixture Using Ultrasound Sonication

2018

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Ammonium Dinitramide (ADN) in its generic form has a long needle shaped structure, which hinders higher solid loading. Therefore, it is of utmost importance to optimize its crystal morphology into octagonal shapes. Moreover, the low critical humidity level of ADN renders it unusable in a humid climate. Hence, encapsulation with a hydrophobic polymer is necessary. In the present work, ADN was synthesized by nitration of potassium sulfamate with mixed acid nitration. The product was then mixed with toluene, graphene, citryl ammonium butyl, Cab-o-sil, and coating polymer (Polystyrene or HTPB) and treated with ultrasound to obtain semi-spherical ADN-coated particles. The method offers a reduction in operating temperature and elimination of ADN melting in the shape-altering process. In addition, the ADN product has a similar particle size and thermal stability compared to those in a conventional ADN melt-prilling method. The ADN product investigated under SEM confirms the particle morphological change from long needles into semi-spherical shapes. The particle size obtained, in the micrometer range, is ideal for higher theoretical maximum density. Furthermore, the ultrasound-treated ADN particles show significant reduction in moisture absorption, from 68% to 16% at 65% relative humidity. The DSC result shows no degradation of thermal stability of the coated particles.

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“…The spray-drying [20][21][22][23] method was suitable for the preparation of heat-sensitive substances due to the stable preparation process, the convenient operation, and the products which did not need to be crushed and sieved after drying. The spray-drying method was used to prepare the spherical RDX with a particle size of 0.5 μm to 4 μm by Jingyu et al [21] with the spray speed of 10 ml/min.…”

Section: Introductionmentioning

confidence: 99%

Study on the Influencing Factors of Ultrafine Spherical RDX during Spray Drying with Low Speed

Wang

Peng

et al. 2019

Journal of Nanomaterials

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Cyclotrimethylene trinitramine (RDX, C3H6N6O6) with the size of 400 to 600 nm was prepared by low-speed spray-drying method. Meanwhile, the crystal morphology, particle size, crystal structure, thermal decomposition properties, and impact sensitivity properties of the raw materials of RDX and the prepared ultrafine spherical RDX were characterized by scanning electron microscope (SEM), laser particle size analyzer (LPSA), X-ray diffractometer (XRD), differential scanning calorimeter (DSC), and impact sensitivity instrument. The factors affecting experimental results were discussed; the size and morphology of RDX crystals were found to be affected by drying temperature, spray speed, and RDX mass fraction in solution. The optimal preparation conditions for the ultrafine spherical RDX were studied, and the results showed that the RDX particles with the best morphology and particle uniformity were prepared when the drying temperature was 90°C, spray speed was 1 ml/min, and the RDX mass fraction in solution was 4%. As a result, the activation energy (Ea) of the ultrafine spherical RDX was lower than that of raw RDX by 24.52 KJ·mol-1, and the characteristic drop (H50) of the ultrafine spherical RDX was higher by 35.3 cm.

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Evaporation Crystallization of RDX by Ultrasonic Spray

Cited by 36 publications

References 51 publications

Formation of Spherical Agglomerates in Cooling Crystallization of Hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine

Formation of Spherical Agglomerates in Cooling Crystallization of Hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine

Prilling and Coating of Ammonium Dinitramide (ADN) Solid Green Propellant in Toluene Mixture Using Ultrasound Sonication

Study on the Influencing Factors of Ultrafine Spherical RDX during Spray Drying with Low Speed

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