Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
  • C06B45/18—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component
  • C06B45/20—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component the component base containing an organic explosive or an organic thermic component
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
  • C06B21/0033—Shaping the mixture
  • C06B21/0066—Shaping the mixture by granulation, e.g. flaking

Definitions

• the invention relates to a process for the preparation of Composite particles of at least a first and at least a second component of each crystalline Explosive, fuel and / or oxidizer by means of cooling or evaporation crystallization.
• the substances mentioned usually come either in the form of bulk or bulk in the form of propellant and explosive moldings used, the particles in the latter case in an in usually polymeric binding material are incorporated.
• the solution becomes transferred to a supersaturated area, the solution in particular by cooling the solution (cooling crystallization), Evaporation of the solvent (evaporation crystallization) or supersaturated combination of both variants can be so that by breaking down this supersaturation of the excess solid is obtained as a crystallizate, the mechanical can be separated from the residual solution.
• the supersaturation can by vacuum (vacuum crystallization), salting out, Failure, if necessary by addition of seed or supply of mechanical energy (agitation) supported become. Crystallization from solutions also takes place for the purification or separation of mixtures, for Concentration of solutions or reduction of Crystal defects or for the modification of the crystalline Phase (production of particles of high purity or with certain particle shape and size) in the form of recrystallization Use.
• Cyclotrimethylenetrinitramine (Hexogen, RDX), cyclotetramethylenetetranitramine (Octogen, HMX), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW, CL20) or the like, in conjunction with less sensitive materials can significantly lower in such composite crystals, as with blends of these materials, i. with mixtures each of pure particles of said materials, was not possible.
• EP 1 090 894 A1 describes a process for the preparation of finely dispersed crystalline explosives by the explosive dissolved in an organic solvent and the solution in a nozzle flow in with the organic Solvent at least partially miscible supercritical Fluid in which the explosive is not or is only slightly soluble, is sprayed. This is the Solvent crystallizing the explosive particles taken up by the supercritical fluid and the Crystalline after expansion of the supercritical fluid in a subcritical, in particular gaseous state of this separated.
• composite particles may be provided that two or more explosives dissolved in the solvent and the solution in the nozzle flow with the supercritical serving as antisolvent Fluid be brought into contact.
• the concentration gradient where immediate after spraying the solution into the antisolvent the Solvent concentration on the surface of a solvent drop is about 100% while in that the solvent drop surrounding solvent insolvent solvent concentration is about 0%.
• the antisolvent in the solvent drops diffused the antisolvent in the solvent drops, so that the Saturation concentration of the explosives in the solvent drop is suddenly exceeded and thereby as already mentioned, to a spontaneous crystallization the explosives is coming.
• EP 1 256 558 A2 is a process for the preparation of a dissolved in a solvent explosive, fuel or oxidizer removed by means of cooling crystallization, by the solution to form the Feststoffkristallisates is cooled to below its saturation temperature.
• the crystals produced while avoiding an insert of seedlings is used to initiate the Crystal formation in the metastable region just below the Saturation temperature ultrasonic energy coupled into the solution.
• the production be provided by composite particles, in which case at least two representatives of said substance group in the solvent be solved. Meanwhile, the production of Composite particles only from components with similar or practically identical saturation temperature and solubility possible in the solvent used and in practice on composite particles of two or more isomers and the same component.
• the invention is therefore based on the object, a simple and inexpensive process for the production of composite particles from virtually any crystalline explosive, Fuels and / or oxidizers by means of cooling or To propose evaporation crystallization.
• this object is achieved in a method of Cooling crystallization of the type mentioned by solved that the second component from the group of nitramines it is chosen that the first component in at least a solvent is dissolved, in which the second component not or only slightly soluble, that the solvent before dissolving the first component and / or the solution solvent and first component the second Component to form a solid / liquid dispersion in particulate form is added, and that the dispersion then below the saturation temperature of the first Components in the solvent cooled and the first Component thereby forming the composite particles deposited on the surface of the particulate second component becomes.
• the second Component selected from the group of nitramines that the first component in at least one solvent is solved, in which the second component is not or only slightly soluble, that the solvent before dissolving the first component and / or the solution of solvent and the first component is the second component under formation a solid / liquid dispersion added in particulate form is, and that the solvent then until above the saturation concentration of the first components evaporated in the solvent and the first component forming the composite particles on the surface the particulate second component is deposited.
• the shell material is the Composite particles by appropriate selection of the solvent (mixture) s largely freely selectable, if as Nuclear material can be used.
• the invention gives thus in particular the possibility of one in many Cases of desired phlegmatization of very reactive nitramines by coating the nitramine particles with a contrast less reactive propellant, explosive or oxidizer.
• the layer structure can be the first, from the dissolved state on the surface the particulate nitramine-deposited component control by adjusting the crystal growth, in usually the more regular crystals grow up, the smaller the cooling rate of the dispersion (cooling crystallization) or the lower the stripping speed of the solvent (evaporation crystallization) is or the slower the crystal growth occurs.
• the mode of action of the method according to the invention on a deposition or on a growth of the dissolved Explosive, fuel or oxidizer on the foreign particles is based on nitramines, surprised inasmuch as in other material systems, in particular from the group of Propellants, explosives and oxidizers, such an effect can not be observed. That's the way it is, for example not possible, the same dissolved substances, which as Shell material ("first component”) for the invention Formation of composite particles with nitramines (“second component”) are capable, i.
• nitramines which from the solved Condition "growing up” on the undissolved nitramine particles, to deposit on second components other than nitramines, being a particulate second component among others
• Metals and metal oxides such as aluminum, aluminum oxide and magnesium oxide, nitrates, such as ammonium nitrate (AN), nitramide, such as ammonium dinitramide (ADN), and other explosives, such as 3-nitro-1,2,4-triazol-5-one (NTO) and 1-diamino-2,2-dinitroethylene (DADE, FOX7), with a particle size of up to 30 microns were tested.
• the sensitivity one (second) component i. as a core material used nitramines, preferably from the group Cyclotrimethylenetrinitramine (Hexogen, RDX), cyclotetramethylenetetranitramine (Octogen, HMX) and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitan (HNIW, CL20), can be significantly reduced by this (second) component with another (first) component with one in contrast, lower sensitivity, for example ammonium dinitramide (ADN), ammonium nitrate (AN), 3-nitro-1,2,4-triazol-5-one (NTO), 1-diamino-2,2-dinitroethylene (DADE, FOX7) or the like, on the surface thereof from the dissolved state is deposited.
• ADN ammonium dinitramide
• AN ammonium nitrate
• NTO 3-nitro-1,2,4-triazol-5-one
• this can be Burning behavior due to the nature and mass ratio of Components in the manner prepared according to the invention
• Composite particles targeted to the respective requirements adjust and generally the performance characteristics of solid fuels, propellant powders, pyrotechnic formulations, propellants for gas generators and set the like targeted.
• the first (dissolved) component ie the "shell material” from the Group of crystalline amine, amide, nitro, nitrate, nitramide and / or perchlorate compounds, in particular from the group ammonium dinitramide (ADN), ammonium nitrate (AN), Potassium nitrate, sodium nitrate, ammonium perchlorate (AP), 2,4,6-trinitrotoluene (TNT), 1,3,5-triamino-2,4,6-trinitrobenzene (TATNB), 3-nitro-1,2,4-triazol-5-one (NTO), hexanitrostilbene (HNS), 1-diamino-2,2-dinitroethylene (DADE, FOX7), FOX12, pentaerythritol tetranitrate (Nitropenta, PETN), hexanitrodiphenylamine (hexyl) and tetranitromethylaniline (Tetryl
• ADN ammonium dinit
• the preparation of the dispersion can be done by that first the component soluble in the respective solvent dissolved herein and the second component of the solution then added to form the dispersion.
• the second component forming a dispersion in the solvent and then solving the first component herein become.
• the first component soluble in the solvent is the solvent with a fraction in the saturation range of these Component in the respective solvent or even scarce is added below or above the saturation region.
• the deposition of the first at the particulate second component can of course in per se known Way by applying a negative pressure (vacuum crystallization) or the like while the dispersion cooled (cooling crystallization) or during the solvent is removed from this (evaporation crystallization).
• the second component in reproducible Shape only from a certain particle size (particle diameter) the nitramine in the dispersion happens.
• the second component with a particle size between 10 ⁇ m and 1000 ⁇ m, preferably between 50 ⁇ m and 500 ⁇ m, in particular between 100 ⁇ m and 300 ⁇ m, the solution or the solvent is added.
• the particulate second component of the dispersion at least during the deposition of the first component at this in Levitation is maintained, which ensures, for example can be, by the dispersion at least temporarily or is stirred continuously.
• the dispersion in vibrations is offset.
• the reproducibility can be improve the inventive method by the deposition of the dissolved first component at the particulate second component is spontaneously initiated, so that the first component evenly with a substantially uniform layer thickness on the particles of the second Component grows up.
• the dispersion may be e.g. by means of ultrasound Vibrations are added, which is particularly true of direct Paths by sonotrodes or by any other means known facilities, such as ultrasonic baths or like that, can happen.
• the amplitude and the frequency such devices can be easily adjusted, for a high reproducibility of the process to care.
• the dispersion may be e.g. by means of at least one vibrated piezoelectric element become. Piezoelectric elements expand during application of an electric field in one direction while they contract in another direction, so that at a predetermined electrical voltage or a predetermined Electric current a reproducible vibration excitation is possible.
• the cooling crystallization used for the production of composite particles, so it is with most material systems advantageous if the dispersion is within a Temperature interval between the saturation temperature of dissolved in the solvent first component and a by 20 C lower temperature, in particular at about 5 ° C. to 15 ° C below the saturation temperature of this component, is set in vibration.
• Antisolvens is meant a fluid which with respect to the first dissolved in the solvent Component acts as an antisolvent and a relatively spontaneous Excretion of the same, especially in the metastable area the solution or the dispersion causes.
• composite particles are particularly for use in propellant powders, explosive charges, pyrotechnic Formulations in gas generators and / or rocket fuels, in particular rocket propellants, suitable, in the latter case, in a suitable Binder system can be introduced.
• a substantially saturated solution from 800 g AN (“first component”) in a corresponding one Amount of demineralised water (“solvent”) prepared is stirred for about 30 min, until all the AN has gone into solution.
• the solution of In demineralized water, HMX particles (“second Component ”) with an average particle size of about Added 200 microns, which is practically insoluble in water are.
• the solid / liquid dispersion obtained in this way is homogenized by stirring and then with a constant Temperature gradient cooled, the dispersion is constantly stirred by means of the propeller stirrer, around the HMX particles in the solution in a homogeneous distribution and in particular to keep it in suspense, so that it does not fall in Sediment the direction of the bottom of the stirred tank.
• AN particles are precipitated from the solution, which at the surface of the HMX particles deposited or to this be attached. With progressive cooling finds a crystal growth of deposited on the HMX particles AN crystals instead.
• the resulting composite particles have a core of HMX with a mean particle size of about 200 microns and a attached to this layer of AN with a layer thickness of about 20 microns.
• NTO 3-nitro-1,2,4-triazol-5-one shell material
• the resulting composite particles have a core of CL20 with a mean particle size of about 300 microns and a mean total particle size of about 380 ⁇ m in total on.
• Example 2 In a procedure corresponding to Example 2 becomes instead of NTO 1-diamino-2,2-dinitroethylene (DADE, FOX7) used as dissolved (first) component.
• the obtained Particles accordingly have a core of CL20 with a average particle size of about 300 microns with a shell material from FOX7 on.
• RDX cyclotrimethylenetrinitramine
• ADN Ammonium dinitramide
• the solid / liquid dispersion thus obtained from the ADN solution with the RDX particles is then cooled with continuous stirring, with the RDX particles be kept in homogeneous distribution. After falling below the saturation temperature of AND in water ADN crystals are eliminated from the solution, which deposited on the surface of the RDX particles. As the cooling progresses, crystal growth takes place the deposited on the RDX particles ADN crystals instead of. Finally, the resulting composite particles taken from the solvent and washed in a conventional manner and dried.
• the resulting composite particles have a core of RDX with a mean particle size of about 50 microns and a total mean particle size of about 120 ⁇ m in total.

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• 2004
  • 2004-01-31 DE DE200410004964 patent/DE102004004964B4/de not_active Expired - Fee Related
  • 2004-12-24 EP EP20040030749 patent/EP1559700A2/fr not_active Withdrawn

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