RESS Recrystallization of RDX Particles Using Dimethylether
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Solution Overview
Problem
Current methods for recrystallizing fine spherical RDX particles are limited by the inability to control particle size and distribution, especially for particles less than 1 micrometer, and existing supercritical fluid processes are inefficient due to high solvent consumption and contamination issues, leading to suboptimal explosive performance and increased sensitivity.
Innovation Solution
A method using a dimethylether compressed gas for recrystallizing RDX particles through the RESS process, involving dissolving RDX in a container, releasing and decompressing the solution to form crystallized particles, and separating them, which results in spherical particles with diameters less than 1 μm and improved uniformity, utilizing eco-friendly dimethylether that can be reused.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional recrystallization methods (milling, solution recrystallization, emulsion crystallization) are used, then particle size can be reduced, but particle size control and distribution uniformity become difficult for particles less than 1 micrometer
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional liquid-based recrystallization to supercritical fluid recrystallization. By changing the physical state of the solvent from liquid to supercritical fluid and adjusting parameters such as pressure (above critical point) and temperature, the invention achieves precise control over particle size and distribution uniformity that cannot be obtained with conventional methods
Solution Approach 2:
The patent utilizes phase transitions of the supercritical solvent. The solvent is heated and pressurized to reach the supercritical state for dissolution, then rapidly depressurized to induce crystallization. This phase transition process enables precise control of particle size and uniform distribution, resolving the contradiction between size reduction and manufacturing precision
2Length of moving object
If spray crystallization/drying process is used to recrystallize particles less than 5 μm, then particle size can be reduced, but high-temperature evaporation process contaminates particles with solvent
Solution Approach 1:
The patent uses phase transition of the supercritical solvent to avoid solvent contamination. By rapidly depressurizing the supercritical solution, the solvent transitions from supercritical state to gas state and evaporates completely, leaving pure crystallized particles without solvent residue. This eliminates the high-temperature evaporation contamination problem of conventional spray drying
Solution Approach 2:
The patent replaces the mechanical/thermal evaporation process of conventional spray drying with a pressure-driven phase transition process. Instead of using high-temperature evaporation to remove solvent, the invention uses rapid pressure reduction to induce solvent phase change and complete evaporation, achieving particle size reduction without solvent contamination
3Length of moving object
If wet crystallization process is used for powder particles weak to shock, then particle size can be controlled, but crystalline phase becomes contaminated with solvent
Solution Approach 1:
The patent uses phase transition of the supercritical solvent to prevent crystalline phase contamination. The rapid depressurization causes the supercritical solvent to transition to gas state and evaporate completely, leaving pure crystallized particles without solvent contamination. This resolves the contamination issue inherent in wet crystallization processes
4Length of moving object
If jet milling process is used for powder particles weak to shock, then particle size can be reduced, but the process cannot be applied due to fundamental disadvantages
Solution Approach 1:
The patent replaces the mechanical jet milling process with a chemical/physical supercritical fluid recrystallization process. Instead of using mechanical impact and shear forces that are unsuitable for shock-sensitive particles, the invention uses supercritical fluid dissolution and phase transition to achieve particle size reduction, making the process applicable to powder particles weak to shock
Solution Approach 2:
The patent applies parameter changes by using supercritical fluid conditions (high pressure and temperature) to dissolve particles, then rapidly changing pressure to induce crystallization. This parameter-based approach replaces mechanical forces with thermodynamic control, enabling processing of shock-sensitive particles that cannot withstand jet milling
5Manufacturing precision
If RESS process using supercritical carbon dioxide is used, then recrystallization can be achieved, but solvent consumption is high and efficiency is low for fine powder particles
Solution Approach 1:
The patent applies parameter changes by optimizing pressure, temperature, and solvent type for the RESS process. By using dimethylether as the supercritical solvent and adjusting operational parameters, the invention achieves significantly higher precipitation rates and efficiency compared to conventional supercritical carbon dioxide RESS processes
Solution Approach 2:
The patent employs a solvent system that can be easily removed and reused. The dimethylether solvent is completely evaporated after the recrystallization process, leaving pure particles, and the solvent can be recovered and reused, reducing overall solvent consumption and improving process efficiency
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
The method achieves high-performance, insensitive RDX particles with enhanced precipitation rates and reduced recrystallization costs, providing a more efficient and economical process for producing fine spherical RDX particles suitable for high explosive applications.
Implementation Method 1
introducing a dimethylether compressed gas into the container and dissolving the RDX to form a RDX solution
Implementation Method 2
releasing and decompressing the RDX solution into atmospheric pressure to form crystallized RDX particles
Implementation Method 3
releasing and decompressing the RDX solution into atmospheric pressure to form crystallized RDX particles
Implementation Method 4
Supercritical fluid can continuously change density from a sparse state close to ideal gas to a high-density state close to liquid density
Data Source
AI summary
The present invention relates to a method for recrystallizing fine spherical cyclotrimethylenetrinitramine (Research Department Explosive, hereinafter, referred to as “RDX”) particles, and the method for recrystallizing fine spherical RDX particles according to the present invention may include (a) introducing a powder material containing RDX into a container, (b) introducing a dimethylether compressed gas into the container and dissolving the RDX to form a RDX solution, (c) releasing and decompressing the RDX solution into atmospheric pressure to form crystallized RDX particles, and (d) separating and collecting the RDX particles.