Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
  • C06B23/007—Ballistic modifiers, burning rate catalysts, burning rate depressing agents, e.g. for gas generating
• • 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
  • C06B21/005—By a process involving melting at least part of the ingredients
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B31/00—Compositions containing an inorganic nitrogen-oxygen salt
  • C06B31/28—Compositions containing an inorganic nitrogen-oxygen salt the salt being ammonium nitrate
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B31/00—Compositions containing an inorganic nitrogen-oxygen salt
  • C06B31/28—Compositions containing an inorganic nitrogen-oxygen salt the salt being ammonium nitrate
  • C06B31/32—Compositions containing an inorganic nitrogen-oxygen salt the salt being ammonium nitrate with a nitrated organic compound

Definitions

• the invention relates to a process for the preparation of Ammonium nitrate (AN) particles mixed with additives by melting the AN and the AN before melting or at least one additive added to the molten AN, the AN melt with the additive to form a droplet dispersion atomises and the droplet dispersion below Receiving the particles is cooled. It is also on particles from with at least one additive added ammonium nitrate (AN) directed.
• AN Ammonium nitrate
• Ammonium nitrate (AN, NH 4 NO 3 ) is of great importance as an oxidizer for propellants and explosives or as a propellant and explosive. It is used in particular in rocket fuels or in gas generators for airbags. While AN decays with slow heating at temperatures above its melting point of 169.5 ° C in water and nitrous oxide (N 2 O), the decomposition may be exothermic with higher temperatures or sudden warming with the release of oxygen, nitrogen and nitrogen oxides as detonation.
• additives in particular from the group of anti-caking agents, Stabilizers, erosion modifiers and / or energy sources. While the latter in particular to increase performance or the specific impulse are added serve the burn-up modifiers for influencing the burning behavior, this either - for example, in rocket fuels - to accelerate or - e.g. in charges for Airbags - to slow down.
• An addition of anti-caking agents is done in particular for Improvement of shelf life and prevention of a Caking the obtained by spray atomization of the melt Particle. Due to the hygroscopicity of AN and the high tendency to form agglomerates can be on in pure form practically not as especially spherical Produce fine particles, the agglomeration tendency increases sharply with decreasing particle size. In the application However, both for the production and the Processing free-flowing, spherical particles with regular Grain shape desired.
• Anti-caking agents become conventional in the manner of a coating or a coating surface on the finished AN particles applied, the AN particles with solutions of anti-caking agents sprayed and the latter on the AN particles are deposited (EP 0 648 190 B1), or it will be fine particulate Anti-caking agents from largely inert substances, like metal oxides, milled with the finished AN particles (US 3,368,929 A, US 2 901 317 A).
• the stabilizers serve to stabilize a respective desired crystal modification of the AN in a desired, widest possible temperature range.
• Pure AN is present as a function of the temperature in five different crystal modifications, namely in the temperature range between 125 ° C and its melting point of 169.5 ° C cubic (modification I), in the temperature range between 84 ° C and 125 ° C at a density of about 1.67 g / cm 3 tetragonal (modification II), in the temperature range of 32 ° C to 84 ° C at a density of about 1.66 g / cm 3 orthorhombic (modification III), between -18 ° C and 32 ° C also orthorhombisch (modification IV), but with a density of about 1.73 g / cm 3 , which corresponds to a density change of about 4% to the density of the modification III, and orthorhombic at temperatures below -18 ° C.
• pseudotretagonal modification V
• the modifications II and V are very similar both in their density and in their lattice structure and provide for example in X-ray diffraction measurements almost identical diagrams.
• the density difference between Modifications III and IV in the heating of AN to temperatures above 32 ° C leads to stresses and cracking in the structure of the shaped propellant charges containing AN as an oxidizer.
• additives are very different Art known (DE 198 44 350 A1, DE 21 25 755 C3, DE 17 67 757 A1, DE 36 42 850 C1, EP 0 405 272 B1, US 3,018 164 A, US 5 071 630 A).
• some additives may have several of the foregoing Fulfill functions, e.g. both as anti-caking agent as also serve as a stabilizer, etc., in particular the An added energy sources whose burning practically in principle influence.
• DE 44 35 524 A1 describes a solid fuel containing AN, wherein the AN, which forms the main part of the solid propellant described, on the one hand in pure form, on the other hand can be used as a phase-stabilized AN.
• a Sprühserstäubungs vide be provided according to the preamble of claim 1, wherein the measures provided for the phase stabilization of AN, the AN melt additives added from the group NiO, KNO 3 and CsNO 3 are selected.
• a subsequent addition of anti-caking agents may be provided in the form of fine particulate silica, sodium lauryl sulfate, tricalcium phosphate or other surfactant surfactants to the finished AN particles.
• the solid propellant described contains, in addition to the possibly phase-stabilized and coated with an anti-caking agent AN particles, a binding system and a high-energy plasticizer and a Abbrandmodifikator of vanadium / molybdenum oxide.
• burned moderators in the form of metal oxides as well as explosives, such as RDX or HMX, and metals, such as aluminum, magnesium or boron can be added to the solid propellant.
• the AN particles themselves, however, have none of the substances mentioned.
• the invention is based on the object, a spray atomization for the production of additives mixed with Particles of AN of the type mentioned above to further develop that the specific impulse or the burning behavior of the AN with the smallest possible amount the added additives can be improved. she is further to such additive-added particles of AN directed.
• the procedural part of this task is inventively in a method of the type mentioned achieved in that the AN as an additive at least one burn-up modifier and / or energy sources from the group of reactive metals and solid explosives and oxidizers in fine particulate form with a particle size of not more than 500 nm admixed and the AN melt with the Fine particles then forming the droplet dispersion is atomized.
• the additive in the AN is increased. So it was found that by an immediate addition of the fine particulate additives with a particle size of at most 500 nm, preferably of at most 100 nm, in particular of at most 50 nm, e.g. between about 5 nm and about 50 nm, in the AN melt the amount of added additives to one Addition of additives in conventional, coarser particulate Form to already finished, solid AN particles otherwise significantly reduce their practically identical effect leaves, depending on the additive, a reduction of the added Quantity by up to about 50% is possible without its effect appreciably affect. That way is the production of a product by the respective Additive imparted properties with a high purity possible.
• particle size within the meaning of the invention is otherwise always addressed the particle diameter.
• explosives and oxidizers are particularly considered, which leads to an increase of the specific momentum of Ammonium nitrate are able.
• the generation of the dispersion from that with the inventive Nanoparticles can be melted at AN known manner, e.g. using a nozzle or Nozzle units with a plurality of nozzles, if necessary under the influence of vibrations, e.g. Ultrasonic, into the system.
• the fine particulate Additives are expediently added to the melt of AN, Of course, they are also the AN in solid Form added and the AN then melted and the Mixture of the spray atomization can be supplied.
• a preferred embodiment provides that a burn-up modifier and / or energy carriers in the form of reactive metals from the group aluminum (Al), iron (Fe), nickel (Ni), Copper (Cu) and zinc (Zn) is added.
• any known solid explosives and / or oxidizers which have a sufficiently hydrophilic character to be wetted by AN in the molten state such as, for example, solid amine, amide, nitro-nitrate-nitramine-chlorate, are also suitable as energy carriers.
• / or perchlorate compounds in particular from the group of ammonium perchlorate (AP, NH 4 ClO 4 ), 2,4,6-trinitrotoluene (TNT), 1,3,5-triamino-2,4,6-trinitrobenzene (TATBN) , 3-nitro-1,2,4-triazol-5-one (NTO), hexanitrostilbene (HNS), cyclotrimethylenetrinitramine (Hexogen, RDX), cyclotetramethylenetetranitramine (octogen, HMX), 2,4,6,8,10,12 -Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW, CL20), 1-diamino-2,2-dinitroethylene (DADE, FOX7), FOX12, pentaerythritol tetranitrate (Nitropenta, PETN), hexanitrodiphenylamine (hexyl) ,
• the energy carriers may be selected from the group of nitramines, in particular octogen (HMX), hexogen (RDX), nitroguandin (NQ) and / or tetryl, and / or from the group of nitrates and / or perchlorates, in particular ammonium perchlorate (AP). , to get voted.
• HMX octogen
• RDX hexogen
• NQ nitroguandin
• AP ammonium perchlorate
• the additive further comprises at least one fine particulate anticaking agent from the group of essentially inert metal oxides having a particle size of at most 500 nm, in particular an anticaking agent from the group of titanium dioxide (TiO 2 ), silicon dioxide (SiO 2 ), iron (II) - (FeO) and / or iron (III) oxide (Fe 2 O 3 ) can be added.
• TiO 2 titanium dioxide
• SiO 2 silicon dioxide
• iron (II) - (FeO) and / or iron (III) oxide Fe 2 O 3
• the additive further comprises at least one anticaking agent and / or stabilizer from the group of metal oxides, metal nitrates, Metal hydroxides, metal carbonates, metal hydroxide nitrates and metal hydroxide carbonates having a particle size of at most 500 nm is admixed.
• anticaking agent and / or stabilizer from the group of metal oxides, metal nitrates, Metal hydroxides, metal carbonates, metal hydroxide nitrates and metal hydroxide carbonates having a particle size of at most 500 nm is admixed.
• Additives are some representatives in particular for phase stabilization known by AN, depending on the temperature in five different crystal modifications present AN in any desired modification should be stabilized to temperature changes in the crystal structure to prevent, due to the different Density of different crystal modifications can lead to tensions and cracks in the structure (see the patent literature cited above).
• an anti-caking agent and / or stabilizer with a metal from the fourth period of the transition metals ie a metal with the atomic number 21 to 30, ie scandium (Sc), titanium (Ti), vanadium (V), Chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) or zinc (Zn).
• an anticaking agent with a metal from the group of nickel, copper and zinc is preferably used, wherein the metal from the fourth period of the transition metals can be used in particular with a valency of 2, so that small amounts of a diamine complex ([Me 2+ (NH 3 ) 2 ]) can be formed, which in particular cause a phase stabilization of the AN or - in still smaller amounts - at least a prevention of caking of the AN particles.
• anti-caking agents and / or stabilizers in the form of nickel, copper and / or zinc oxide or hydroxide, such as NiO, CuO, ZnO, Ni (OH) 2 , Cu (OH) 2 and / or Zn (OH) 2 .
• an anti-caking agent and / or stabilizer of the aforementioned type is added with a metal from the first main group (alkali metal), wherein preferably such an additive with a metal from the group sodium (Na) and potassium (K) is used.
• alkali metal a metal from the first main group
• potassium nitrate (KNO 3 ) and sodium nitrate (NaNO 3 ) have been found to be particularly advantageous.
• an anti-caking agent and / or stabilizer of the aforementioned Type with a metal from the second main group is added, preferably one such Additive with a metal from the group magnesium (Mg) and Calcium (Ca), for example calcium oxide (CaO) and / or magnesium oxide (MgO) is used.
• oxides Me x O, MeO, Me 2 O 3, etc.
• nitrates Me NO 3 , Me (NO 3 ) 2 , Me (NO 3 ) 3, etc.
• hydroxides MeOH, Me (OH) 2 , Me (OH) 3, etc.
• carbonates Me 2 CO 3
• At least one burn-up modifier from the group of catalytically active metal oxides having a particle size of at most 500 nm is admixed to the AN, in particular a burn-up modifier from the group lead oxide, in particular lead (II).
• oxide (PbO), alumina (Al 2 O 3 ), copper (I) - (Cu 2 O) and / or copper (II) oxide (CuO) can be added, which for influencing the burning rate of AN at certain pressure conditions in is capable of and can also be used in relation to the prior art lower quantities.
• inventive method can both continuously as well as semicontinuously or batchwise be performed.
• the invention also relates to particles comprising at least one Additive ammonium nitrate (AN), which in particular produced according to a method of the aforementioned type are and as an additive at least one erosion modifier and / or energy carriers from the group of reactive Metals and solid explosives and oxidizers in fine particulate form with a particle size of at most 500 nm, preferably of at most 100 nm, in particular of at most 50 nm, e.g. between about 5 nm and about 50 nm, contain, whereby a high product unit is possible.
• AN Additive ammonium nitrate
• the particles contain at least a burn-up modifier and / or energy source the above in connection with the method according to the invention
• the invention is based on an embodiment explained in more detail.
• AN ammonium nitrate
• the melt becomes an energy source in the form of fine aluminum powder (Al) in one part of 1 mass% based on the mass of AN with a middle one Particle diameter of about 20 nm and an anti-caking agent in the form of zinc (II) oxide (ZnO) in one part of 0.08 mass% based on the mass of AN in fine particulate Shape with a mean particle diameter of added about 50 nm and the mixture by means of a propeller stirrer Homogenized for about an hour.
• the speed of the Agitator is set to 300 rpm.
• the particles obtained after solidification of the AN droplets have an average particle diameter of about 50 microns.
• the particle shape is spherical and regular;
• the product produced is pourable and agglomerated neither in the two-fluid nozzle nor after a longer service life. It has a specific impulse which is increased compared to pure AN on.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)

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• 2003
  • 2003-07-17 DE DE2003132729 patent/DE10332729A1/de not_active Ceased
• 2004
  • 2004-07-08 EP EP20040016067 patent/EP1498403A2/fr not_active Withdrawn

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