KR100239893B1 - Method for making fine particles of ñ -hniw - Google Patents

Abstract

The present invention is a crystallization method for producing ε hexanitrohexaazaisourchitan (HNIW), which is used as an oxidant in various rocket solid propellants or explosives, with an average particle size of 5 μm or less, and a crystallizer in which HNIW is crystallized. It is a method for producing ε-type HNIW of fine size by adding solid particles having water solubility to the nucleation promoting and grinding agent.

Description

Method for producing ε-type HNI crystals of fine size

The present invention relates to a crystallization method for producing ε hexanitrohexaazaisourchitan (hexanitrohexaazaisowurtzitane aka CL-20, hereinafter referred to as HNIW) used as an oxidant in various propellants or explosives for various rockets in an average particle size of 5 μm or less. It is about. HNIW has high density and high energy compared to Cyclotrimethylene Trinitramine (RDX) and Cyclotetramethylene Tetranitramine (HMX), which are widely used as oxidants in rocket solid propellants and explosives. It is a material that is in the spotlight as a new oxidant.

HNIW is known to exist at room temperature and atmospheric pressure to four homomorphs (α, β, γ and ε) to date due to the structural properties of the material. Among these four homogeneous ideal bodies, the ε-type HNIW, which has the highest thermodynamic stability and density, is currently used as an oxidant in various rocket solid propellants or explosives.

To be used as a solid oxidant in rocket solid propellants or explosives, it must have various particle sizes and appropriate size distributions to satisfy not only chemical requirements such as purity, but also high filling efficiency and physical properties of the propellant and explosives themselves. In particular, an oxidant having a particle size of several μm is essential to increase the oxidant filling rate of the solid propellant. Until now, a method of mechanically crushing large particles using a grinder has been generally used, but this mechanical grinding method has a disadvantage in that a separate equipment for the grinding process is required.

Therefore, the present invention improves the disadvantages of the conventional mechanical grinding method, which requires a separate equipment for the grinding process as described above, and makes the process complicated, and has various particle sizes and appropriate size distribution without a separate grinding process and equipment. It is possible to prepare a solid propellant and a solid oxidant.

The present invention relates to a crystallization method for producing an ε-type HNIW to a fine size as an oxidant in various solid rocket propellants or explosives, and more specifically 5㎛ the solid particles having water solubility in the crystallization crystallized HNIW is crystallized The present invention relates to a crystallization method for producing ε-type HNIW having the following fine size.

According to the crystallization method of the present invention, HNIW is dissolved in HNIW selected from a solvent having a carbonyl group, such as esters or ketones, a hydrocarbon of cyanide hydrocarbons, and an ether, as a dissolving agent. HNIW is crystallized by adding and mixing a solvent having low solubility to HNIW selected from solvents of halogenated hydrocarbons and alcohols as a precipitant, wherein the water-soluble inorganic or organic crystals are used as nucleation promoters and grinding agents to It is to prepare a ε-type HNIW crystal having a fine size.

In general, HNIW has high solubility in solvents of carbonyl groups such as esters and ketones, hydrocarbons of cyanide hydrocarbons and ethers, but low solubility in solvents of hydrocarbons, halogenated hydrocarbons and alcohols. Therefore, when the HNIW is dissolved in a soluble solvent and a low solubility solvent is added, the nucleus of the HNIW immediately occurs. Initial crystals produced in this way are β-type HNIWs, but over time, these β-type HNIWs are transferred to ε-type HNIWs through a transition process in solution.

This transition to ε causes supersaturation of HNIW, which causes the early transition of ε-type HNIW crystals to grow over time and crystallize into large particles. However, crystallization by crystallizing HNIW crystallization with very low solubility crystals with respect to solvents used for dissolution or precipitation of crystals promotes heterogeneous nucleation so that HNIW is produced with a fine crystal size. do. In addition, these crystals act as a crusher to break the crystals due to the impact between the crystallized HNIW and the injected crystals.

Therefore, the present invention, which crystallizes the HNIW in the state in which the HNIW and other kinds of crystals are injected, can easily prepare crystals having a very fine size without a separate grinding process and equipment.

Filtering the crystals after the crystallization operation is completed, the crystals include crystals added as a grinding and nucleation promoter. Therefore, in order to produce pure ε-type HNIW with fine size, it is necessary to remove the added crystals. Since HNIW has a very low solubility in water, the difference in solubility in solvents can be used to separate HNIW and crystals added as grinding and nucleation promoters.

In the present invention, as the nucleation promoting and grinding agent, inorganic and organic crystals having high solubility in water and low solubility in a solvent recrystallizing HNIW were used. These impurities, except HNIW, are removed through a simple process of washing the filtered crystals with water, making it easy to produce pure ε-type HNIW free of impurities.

In the method of the present invention, esters used as solubilizers are preferably ethyl acetate and tetrahydrofuran, ketones are preferably acetone and cyanide hydrocarbons are preferably acetonitrile.

Moreover, heptane and hexane are preferable hydrocarbons used as a precipitant, methylene chloride, chloroform, and carbon tetrachloride are preferable, and alcohol, methanol, ethanol, and 2-propanol are preferable.

In the present invention, the water-soluble crystals used as nucleation promoting and grinding agents are preferably urea, salt and potassium nitrate, and the amount of water-soluble crystals used as nucleating promoting and grinding agents is 4 to 10 times by weight relative to the amount of HNIW to be crystallized. It is preferable to use in the range of.

Metal powders or balls may be used as materials that act as a grinding agent, but since they are mainly present in the lower layer in the solution due to their high density, they may lack product uniformity and also in crystallizers. Its use is excluded from the present invention as it may impact the crystallizer and stirrer while flowing.

In the present invention, since the particle size of the HNIW prepared from the particles used as the nucleation accelerator and the grinding agent has a large difference, the porosity of a little smaller than the particles used as the nucleation accelerator and the grinding agent when the slurry in the crystallizer is filtered. Filtration through the net can promote nucleation and remove significant amounts of pulverizer, thus reducing the amount of water to remove impurities remaining in the HNIW crystals.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples.

Example 1

While maintaining the crystallizer at room temperature, HNIW and ethyl acetate were mixed and dissolved in a weight ratio of 1: 4, and then about 1500 µm of urea crystals were added in an amount of 7 times the used HNIW, and the crystals were uniform in the crystallizer. Stir to make a distribution. 30 times the amount of methylene chloride based on the amount of HNIW used was added to the crystallizer under stirring to precipitate crystals. This crystallization operation produces β-type initial HNIW crystals, and after about 6 hours of continuous agitation, β-type initial HNIW crystals are transferred to ε-type crystals, and nucleated and comminuted to undergo microscopic ε Made of type HNIW. The filtered crystals were washed with 4 times the water for the amount of urea used and then dried to analyze the particle size. The average size was about 3 μm. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

Example 2

While maintaining the crystallizer at room temperature, HNIW and ethyl acetate were mixed and dissolved in a weight ratio of 1: 4, and salt crystals of about 500 µm in size were added in an amount of 8 times to the used HNIW, and then the crystals were uniform in the crystallizer. Stirred to one distribution. 30 times the amount of methylene chloride based on the amount of HNIW used was added to the crystallizer under stirring to precipitate crystals. These crystals were subjected to about 6 hours of transition and grinding to produce ε-type HNIW of fine size. The filtered crystals were washed with 7 times the amount of water for the amount of salt used and then dried to analyze the particle size. The average size was about 3 μm. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

Example 3

While maintaining the crystallizer at room temperature, HNIW and acetone were mixed and dissolved in a weight ratio of 1: 2, and the salt crystals used in Example 2 were added in an amount of 8 times to the used HNIW, and the crystals were uniform in the crystallizer. Stir to make a distribution. 30 times the amount of methylene chloride based on the amount of HNIW used was added to the crystallizer under stirring to precipitate crystals. These crystals were subjected to about 6 hours of transition and grinding to produce ε-type HNIW of fine size. The filtered crystals were washed with 7 times the amount of water for the amount of salt used and then dried to analyze the particle size. The average size was about 3 μm. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

Example 4

After dissolving HNIW and tetrahydrofuran in a weight ratio of 1: 3 in a crystallizer maintained at room temperature, the salt crystals used in Example 2 were added in an amount of 8 times the used HNIW, and the crystals were Stirred to make a uniform distribution. 30 times the amount of methylene chloride based on the amount of HNIW used was added to the crystallizer under stirring to precipitate crystals. These crystals were subjected to about 6 hours of transition and grinding to produce ε-type HNIW of fine size. The filtered crystals were washed with 7 times the amount of water for the amount of salt used and then dried to analyze the particle size. The average size was about 3 μm. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

Example 5

While maintaining the crystallizer at room temperature, ε-type HNIW having an average size of about 30 μm, methylene chloride, and urea used in Example 1 were mixed at a weight ratio of 1: 30: 7, and the particles were uniformly distributed in the crystallizer. Stir for 8 hours and then filter. The filtered crystals were washed with four times the amount of water for the amount of urea used and then dried to analyze the particle size. The average size was about 5 탆. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

Example 6

While maintaining the crystallizer at room temperature, ε-type HNIW having an average size of about 30 μm, chloroform, and potassium nitrate of about 300 μm are mixed at a weight ratio of 1: 30: 8, and the particles are uniformly distributed in the crystallizer for about 8 hours. Stir for and filter. The filtered crystals were washed with 10 times the amount of water based on the amount of potassium nitrate used and then dried to analyze the particle size. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

Example 7

While maintaining the crystallizer at room temperature, ε-type HNIW having an average size of about 30 μm, heptane, and potassium nitrate used in Example 6 were mixed at a weight ratio of 1: 30: 7, and the particles were uniformly distributed in the crystallizer. Stir for 8 hours and then filter. The filtered crystals were washed with 10 times the amount of water based on the amount of potassium nitrate used and then dried to analyze the particle size. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

Example 8

While maintaining the crystallizer at room temperature, ε-type HNIW having an average size of about 30 μm, 2-propanol, and potassium nitrate used in Example 6 were mixed at a weight ratio of 1: 30: 7, and particles were uniformly distributed in the crystallizer. Stir for about 8 hours and filter. The filtered crystals were washed with 10 times the amount of water based on the amount of potassium nitrate used and then dried to analyze the particle size. The prepared HNIW was found to be pure ε-type crystal by Fourier transform infrared spectroscopy (FTIR) analysis.

The present invention, which crystallizes the HNIW in the state in which HNIW and other kinds of crystals are injected, makes it possible to easily prepare crystals having a very fine size without the need for a separate grinding process, and also has a grinding device for producing a fine particle size HNIW. There is an advantage in terms of economics because it becomes unnecessary.

Claims (9)

After dissolving HNIW using a solvent having high solubility in HNIW selected from solvents of esters, ketones, cyanide hydrocarbons and ethers, the solubility in HNIW selected from solvents of hydrocarbons, halogenated hydrocarbons and alcohols Crystallization by adding a low solvent as a precipitant and mixing, wherein inorganic or organic crystals having water solubility are used as nucleation promoters and grinding agents to produce ε-type HNIW crystals having a fine size of 5 μm or less. The process according to claim 1, wherein the esters used as the solubilizer are selected from the group consisting of ethyl acetate and tetrahydrofuran. The method according to claim 1, wherein the ketones used as the solvent are acetone. The method according to claim 1, wherein the cyanide hydrocarbons used as the solvent are acetonitrile. The process according to claim 1 or 2, wherein the hydrocarbon used as precipitant is selected from the group consisting of heptane and hexane. The process according to claim 1 or 2, wherein the halogenated hydrocarbons used as precipitants are selected from the group consisting of methylene chloride, chloroform, carbon tetrachloride. The process according to claim 1 or 2, wherein the alcohols used as precipitants are selected from the group consisting of methanol, ethanol and 2-propanol. The process according to claim 1 or 2, wherein the water soluble crystals used as nucleation promoting and grinding agents are selected from urea, salt, potassium nitrate. The method according to claim 1 or 2, wherein the amount of water soluble crystals used as nucleation promoting and grinding agents ranges from 4 to 10 times by weight relative to the amount of HNIW to be crystallized.