Dinitramide Oxidizer Salt Particle Preparation via Solvent Sublimation
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Solution Overview
Problem
The production of oxidizer salts from the dinitramide group often results in irregular particles with high hygroscopicity and sensitivity to friction and impact, making them difficult to process safely and efficiently, and existing methods like melting and emulsification lead to quality losses and safety risks.
Innovation Solution
A process involving dissolving dinitramide in water or ammonia, cooling the solution to below the solvent's freezing point, and subliming the solvent to produce compact, spherical particles that avoid agglomeration and thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxidizer salts are produced by conventional methods, then particles are formed, but the particles have irregular shapes, high hygroscopicity, and high sensitivity to friction and impact
Solution Approach 1:
The patent applies phase transition by cooling the solution below the solvent's freezing point to solidify the solvent and crystallize the particles, then subliming the solid solvent to remove it. This phase transition approach (liquid→solid→gas) enables formation of compact spherical particles without the harmful sensitivity associated with conventional production methods
Solution Approach 2:
The patent changes physical parameters including temperature (cooling below freezing point), pressure (for sublimation), and phase state of the solvent. By controlling these parameters, the process transforms the solvent from liquid to solid and then to gas, enabling particle formation with improved morphology and reduced sensitivity to friction and impact
2Shape
If oxidizer salts are melted and emulsified to produce particles, then spherical particles can be obtained, but thermal stress increases decomposition and quality losses occur
Solution Approach 1:
Instead of melting the oxidizer salt, the patent uses phase transition of the solvent (liquid→solid→gas) to form particles. The solvent is cooled to solidify and then sublimed to remove it, leaving spherical particles. This avoids thermal stress on the oxidizer salt that would cause decomposition and quality losses
Solution Approach 2:
The patent replaces the mechanical emulsification process with a phase transition-based crystallization process. Instead of using mechanical stirring and emulsification of melted salt, the process uses controlled cooling and sublimation to crystallize particles directly from solution, eliminating mechanical stress and thermal degradation
3Productivity
If oxidizer salts are subjected to high shear forces during emulsification, then particles can be formed, but safety risks increase due to high sensitivity to friction and impact
Solution Approach 1:
The patent replaces mechanical emulsification with high shear forces with a gentle phase transition process. The particles form through controlled cooling and sublimation without mechanical agitation, eliminating safety risks associated with friction and impact on sensitive oxidizer salts while maintaining production efficiency
Solution Approach 2:
The patent uses phase transition of the solvent (liquid→solid→gas) as the mechanism for particle formation instead of mechanical emulsification. This phase transition process occurs without high shear forces, ensuring safety when processing highly sensitive oxidizer salts
4Manufacturing precision
If recrystallization is performed multiple times to improve grain properties, then particle quality improves, but processing time and complexity increase
Solution Approach 1:
The patent uses a single phase transition cycle (cooling below freezing point followed by sublimation) to directly produce high-quality spherical particles with excellent grain properties. This one-step approach eliminates the need for multiple recrystallization cycles, significantly reducing processing time while maintaining or improving particle quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method yields high-density, pure, and thermally stable particles with a rounded morphology, reducing decomposition and safety risks, and is particularly effective for challenging salts like ammonium dinitramide.
Implementation Method 1
cooling the solution to below the solvent's freezing point, so that the solvent is in solid phase in order to crystallize the particles of the dinitramide
Implementation Method 2
subliming the solvent to produce compact, spherical particles that avoid agglomeration and thermal stress
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A process for the production of particles from oxidizer salts of the dinitramide group, in particular ammonium (ADN), potassium (KDN) and guanylurea dinitramide (KUDN), is proposed, comprising the following steps: (a) dissolving the dinitramide in at least one solvent from the group consisting of water and ammonia to obtain a solution of the dinitramide; (b) subsequently cooling the solution of the oxidizer salt to a temperature below the freezing point of the at least one solvent, so that the solvent is in the solid phase to crystallize the particles of the dinitramide; and (c) subsequently subliming at least a portion of the at least one solvent present in the solid phase to obtain the particles of the dinitramide.