Spherical ammonium perchlorate and preparation method and application thereof

Abstract

The application discloses spherical-like ammonium perchlorate and a preparation method and application thereof, and belongs to the technical field of ammonium perchlorate. The preparation method comprises the following steps: stirring and blending a supersaturated ammonium perchlorate aqueous solution containing an ammonium salt and a second-phase solvent, and heating to promote the dissolution of residual ammonium perchlorate; keeping the stirring state and cooling, and after removing water and the second-phase solvent, drying the remaining solid phase; wherein the supersaturated ammonium perchlorate aqueous solution containing an ammonium salt and the second-phase solvent are not soluble, under the action of a high-speed flow field, the ammonium perchlorate crystal nucleus separated out in the microdroplets of the aqueous solution precipitates into the second-phase solvent, and the crystal morphology is continuously modified into a spherical-like shape. The method has the advantages of simple operation, controllable particle size, high safety, easy separation of the product and the like. The ammonium perchlorate prepared by the above method is in a spherical-like shape, and can reduce the impact sensitivity and friction sensitivity compared with non-spherical ammonium perchlorate. The spherical-like ammonium perchlorate can be used for preparing propellants.

Description

Technical Field

[0001] This invention relates to the field of ammonium perchlorate technology, and more specifically, to a spherical ammonium perchlorate, its preparation method, and its application. Background Technology

[0002] Ammonium perchlorate (NH4ClO4), as a strong oxidizing agent, possesses advantages such as high density, high oxygen content, and good thermal and chemical stability, thus occupying an extremely important position in solid propellants. Typically, ammonium perchlorate is one of the main components of solid propellants, accounting for 60%-80% of the total weight of the solid propellant.

[0003] Spherical ammonium perchlorate has the advantage of reduced sensitivity. Compared with non-spherical ammonium perchlorate crystals, the impact sensitivity of spherical ammonium perchlorate can be reduced from 70% to 38%, and the friction sensitivity from 88% to 43%. This is because when non-spherical ammonium perchlorate is subjected to external impact or friction, the internal bubbles, cavities, defects, and irregular morphologies have a significant effect, easily forming local hot spots and reducing the overall stability of the ammonium perchlorate. In contrast, spherical ammonium perchlorate has a regular and compact arrangement, with virtually no points or edges that interact with external forces, resulting in high stability. In addition, spherical ammonium perchlorate can also improve crystal flowability, inhibit particle agglomeration, reduce crystal defects, and increase packing density, which is beneficial for improving the performance of ammonium perchlorate in propellants.

[0004] Currently, commonly used methods for preparing ammonium perchlorate include chemical vapor deposition, mechanical ball milling, air jet milling, solvent-to-solvent method, spray drying, and supercritical fluid method. Among these, mechanical ball milling and air jet milling are solid-phase methods for pulverizing large particles of ammonium perchlorate, while solvent-to-solvent method, spray drying, and supercritical fluid method are liquid-phase methods for preparing ammonium perchlorate.

[0005] The aforementioned chemical vapor deposition (CVD) method is a gas-phase method. It involves mixing anhydrous perchloric acid vapor and ammonia gas in a reaction chamber using an inert gas as a carrier gas, allowing them to react fully to obtain ultrafine ammonium perchlorate particles. Because CVD preparation of nanoparticles requires chemical reactions within the equipment, these reactions can corrode the equipment, resulting in high maintenance costs.

[0006] Mechanical ball milling utilizes the shearing and extrusion forces generated by the continuous collision and friction between the grinding media in a ball mill to crush ammonium perchlorate raw materials. However, it has high equipment requirements, high energy consumption, and low preparation efficiency.

[0007] In the gas pulverization method, ammonium perchlorate particles rotate and collide continuously in the pulverization chamber under the action of high-speed airflow, so as to achieve the purpose of particle pulverization and refinement. However, it also has disadvantages such as high energy consumption and high equipment cost.

[0008] The solvent-antisolvent method involves adding a solution of ammonium perchlorate at a specific concentration to an antisolvent at a controlled rate. Utilizing the difference in solubility of ammonium perchlorate in the solvent and antisolvent, supersaturation occurs, causing the ammonium perchlorate to precipitate from the solvent. The solvent-antisolvent method produces products with smaller particle sizes and generates a larger amount of waste solvent.

[0009] Spray drying disperses ammonium perchlorate solution into small droplets using an atomizer, and then rapidly dries the atomized droplets into fine particles using high-temperature heating. Compared with solid-phase drying, spray drying produces particles with smaller diameters. However, spray drying has disadvantages such as larger and more complex equipment, larger footprint, higher energy consumption, and lower thermal efficiency.

[0010] The supercritical fluid method involves dissolving ammonium perchlorate in a supercritical fluid. Utilizing the solvation capability of supercritical fluids, which is highly sensitive to changes in temperature and pressure, decompression and expansion occur within a very short time, yielding a large quantity of tiny, uniformly sized ultrafine particles. However, the supercritical state involves a high-temperature, high-pressure environment, making the preparation process inherently dangerous.

[0011] In view of this, the present invention is proposed. Summary of the Invention

[0012] The purpose of this invention is to provide a spherical ammonium perchlorate, its preparation method, and its application, so as to solve or improve the above-mentioned technical problems.

[0013] This invention can be implemented as follows:

[0014] In a first aspect, the present invention provides a method for preparing spherical ammonium perchlorate, comprising the following steps: stirring and mixing a supersaturated aqueous solution of ammonium perchlorate containing ammonium salt with a second phase solvent, heating to promote the dissolution of the remaining ammonium perchlorate; maintaining the stirring state and cooling down, removing water and the second phase solvent, and drying the remaining solid phase;

[0015] Among them, the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is immiscible with the second phase solvent.

[0016] In an optional embodiment, the mass ratio of ammonium perchlorate to ammonium salt in the supersaturated aqueous solution containing ammonium salt is 2:1 to 10:1.

[0017] In an optional embodiment, the ammonium salt includes at least one of ammonium nitrate, ammonium sulfate, and ammonium chloride.

[0018] In an optional embodiment, the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is 1:5 to 1:100.

[0019] In an optional embodiment, the second phase solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethylene, and 1,2-dichloroethylene.

[0020] In an optional embodiment, the stirring speed is 400 rpm to 900 rpm.

[0021] In an optional embodiment, the heating temperature is 40°C to 90°C.

[0022] In an optional embodiment, the cooling rate is 1°C / min to 30°C / min.

[0023] In an optional implementation, after cooling, the mixture is allowed to stand before removing water and the second phase solvent.

[0024] In an optional implementation, the settling time is 2h to 24h, and / or the settling temperature is room temperature.

[0025] Secondly, the present invention provides a spherical ammonium perchlorate, which is prepared by any of the preparation methods described in the foregoing embodiments.

[0026] In an optional embodiment, the particle size of the spherical ammonium perchlorate is 3 μm to 130 μm.

[0027] Thirdly, the present invention provides an application of the spherical ammonium perchlorate as described in the foregoing embodiments, which can be used to prepare propellants.

[0028] Fourthly, the present invention provides a propellant in which the oxidant comprises the spherical ammonium perchlorate of the foregoing embodiments.

[0029] The beneficial effects of this invention include:

[0030] The method for preparing near-spherical ammonium perchlorate provided by this invention involves forming microdroplets of a supersaturated ammonium perchlorate solution in an immiscible second-phase solvent under stirring conditions. During the cooling crystallization process, ammonium perchlorate nuclei precipitate. Utilizing gravity, these nuclei settle into the second-phase solvent and further form near-spherical ammonium perchlorate crystals. In this process, the fine ammonium perchlorate particles precipitated during cooling within the high-speed flow field of water and the second-phase solvent serve as sites for further crystal growth; therefore, this method eliminates the need for additional seed crystals. Furthermore, since the solubility of ammonium perchlorate is temperature-sensitive, it rapidly reaches a high supersaturation state and precipitates during cooling, while the ammonium salt used remains ionic in the solution before reaching supersaturation. During the crystallization process, anions in the ammonium salt are directionally adsorbed onto the ammonium perchlorate crystal surface, inhibiting the adsorption rate of perchlorate ions and thus slowing the growth of the dominant crystal facets. The resulting crystals tend to be near-spherical, and their morphology is further refined in the second-phase solvent.

[0031] The above method has the advantages of low cost, simple operation, short time consumption, no need to add seed crystals, controllable particle size, high safety performance, easy product separation, and reusable solvent.

[0032] The ammonium perchlorate prepared by the above method has a spherical shape, which is beneficial for reducing impact and friction sensitivity. This spherical ammonium perchlorate can be used to prepare propellants. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a SEM image of ammonium perchlorate prepared in Example 1 of the present invention;

[0035] Figure 2 Here is a SEM image of the ammonium perchlorate prepared in Example 5;

[0036] Figure 3 The particle size distribution diagram of ammonium perchlorate prepared in Example 5 is shown.

[0037] Figure 4 The image shows the EDS diagram of ammonium perchlorate prepared in Comparative Example 1. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0039] The following provides a detailed description of the spherical ammonium perchlorate provided in this application, its preparation method, and its application.

[0040] This application proposes a method for preparing spherical ammonium perchlorate, which includes the following steps: stirring and mixing a supersaturated ammonium perchlorate aqueous solution containing ammonium salt with a second phase solvent, heating to promote the dissolution of the remaining ammonium perchlorate; maintaining the stirring state and cooling down, removing water and the second phase solvent, and drying the remaining solid;

[0041] Among them, the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is immiscible with the second phase solvent.

[0042] By stirring, a supersaturated ammonium perchlorate solution forms microdroplets in the second phase solvent. When the ammonium perchlorate crystal nuclei precipitate during cooling and crystallization, they settle down, thus forming near-spherical particles in the second phase solvent.

[0043] In some alternative methods, the mass ratio of ammonium perchlorate to ammonium salt in a supersaturated aqueous solution containing ammonium salt can be from 2:1 to 10:1, such as 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, or other values ​​within the range of 2:1 to 10:1.

[0044] The ammonium salt may, by way of example but not by way of limitation, include at least one of ammonium nitrate, ammonium sulfate and ammonium chloride.

[0045] If the mass ratio of ammonium perchlorate to ammonium salt is less than 2:1 (e.g., 1:1), when the amount of ammonium perchlorate added is controlled at a certain level, too much ammonium salt can easily lead to impurities in the resulting spherical ammonium perchlorate crystals. If the mass ratio of ammonium perchlorate to ammonium salt is greater than 2:1 (e.g., 12:1), the competitive adsorption of anions in the ammonium salt is too weak, making it difficult to delay the growth of the dominant crystal face of ammonium perchlorate, which can easily lead to the resulting ammonium perchlorate crystals deviating from the spherical shape (polyhedral shape).

[0046] In some alternative methods, the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt can be from 1:5 to 1:100, such as 1:5, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100, or other values ​​within the range of 1:5 to 1:100.

[0047] The second phase solvent may, by way of example but not by way of limitation, include at least one of dichloromethane, trichloromethane, tetrachloroethylene, and 1,2-dichloroethylene.

[0048] If the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is less than 1:5 (e.g., 1:4), it is not conducive to the precipitation of ammonium perchlorate crystals into a near-spherical shape, and the proportion of polyhedral ammonium perchlorate crystals increases. If the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is greater than 1:100 (e.g., 1:120), the amount of near-spherical ammonium perchlorate product obtained in a single preparation is too small, which is not conducive to rapid preparation.

[0049] In some optional methods, the stirring is high-speed stirring, and the stirring speed can be 400 rpm to 900 rpm, such as 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or 900 rpm, or other values ​​within the range of 400 rpm to 900 rpm.

[0050] The stirring speed affects the particle size of ammonium perchlorate crystals. The higher the stirring speed, the smaller the size of the microdroplets formed, the less ammonium perchlorate solute they contain, and the easier it is to obtain small-sized ammonium perchlorate crystals. However, if the stirring speed is higher than 900 rpm, the solvent surface is easily agitated, which is not conducive to the formation of stable microdroplets and causes process instability.

[0051] In this invention, heating is primarily used to promote the dissolution of the remaining ammonium perchlorate (in water). Furthermore, the fine ammonium perchlorate particles precipitated during the cooling process can serve as sites for further crystal growth. Therefore, the method provided by this invention eliminates the need for additional seed crystals.

[0052] In some optional methods, the heating temperature can be 40℃ to 90℃, such as 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃ or 90℃, or other values ​​within the range of 40℃ to 90℃.

[0053] If the heating temperature is below 40℃, it is not conducive to the dissolution of the remaining ammonium perchlorate; if the heating temperature is above 90℃, it is not conducive to retaining some of the incompletely dissolved fine particles as nucleation sites for cooling crystallization.

[0054] In some optional methods, the cooling rate can be from 1℃ / min to 30℃ / min, such as 1℃ / min, 2℃ / min, 5℃ / min, 8℃ / min, 10℃ / min, 12℃ / min, 15℃ / min, 18℃ / min, 20℃ / min, 22℃ / min, 25℃ / min, 28℃ / min or 30℃ / min, or other values ​​within the range of 1℃ / min to 30℃ / min.

[0055] The cooling rate also affects the particle size of ammonium perchlorate crystals. The faster the cooling rate, the faster the saturation of the ammonium perchlorate solution increases, the more crystal nuclei are generated within a single microdroplet, and the smaller the resulting crystal particle size. However, if the cooling rate is too fast (exceeding 30℃ / min), it is not conducive to final temperature control and affects batch stability.

[0056] Furthermore, after cooling, the mixture can be allowed to stand before removing water and the second phase solvent.

[0057] The settling time can be from 2h to 24h, such as 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, or other values ​​within the range of 2h to 24h.

[0058] The above-mentioned settling process can be carried out at room temperature.

[0059] After standing, the upper layer of water and the second phase of solvent are removed in sequence.

[0060] Continuing from the above, the preparation principle of the near-spherical ammonium perchlorate provided by this invention includes: under high-speed stirring, a supersaturated ammonium perchlorate solution forms microdroplets in an immiscible second-phase solvent, and ammonium perchlorate crystal nuclei precipitate during the cooling crystallization process; the crystal nuclei settle into the second-phase solvent and further form near-spherical ammonium perchlorate crystals, while impurities and small crystals redissolve and are eliminated during the settling process. In the high-speed flow field of water and the second-phase solvent, the fine ammonium perchlorate particles precipitated during the cooling process can serve as sites for further crystal growth; therefore, the two-phase crystallization method does not require the addition of additional seed crystals. The solubility of ammonium perchlorate is temperature-sensitive; during the cooling process, ammonium perchlorate can rapidly reach a high supersaturation state and precipitate, while the ammonium salt used has not yet reached supersaturation and still exists in solution in ionic form. During the crystallization of ammonium perchlorate, anions in the ammonium salt are directionally adsorbed on the crystal surface of ammonium perchlorate, which inhibits the adsorption rate of perchlorate ions, thereby slowing down the growth of the dominant crystal surface of ammonium perchlorate. The resulting crystals tend to be spherical, and their morphology is further improved in the second phase solvent.

[0061] Therefore, this invention provides a low-cost and rapid method for preparing near-spherical ammonium perchlorate. This method involves dispersing saturated ammonium perchlorate microdroplets using an immiscible second-phase solvent under high-speed stirring, followed by a cooling crystallization process to prepare near-spherical ammonium perchlorate crystals. This two-phase crystallization method has advantages such as simple operation, no need for seed crystals, controllable particle size, high safety, easy product separation, and reusable solvent.

[0062] Accordingly, the present invention also provides a spherical ammonium perchlorate, which is prepared by the above-described preparation method.

[0063] The ammonium perchlorate is a near-spherical particle with adjustable particle size. For example, the particle size of this near-spherical ammonium perchlorate can be 3μm to 130μm, such as 3μm, 5μm, 10μm, 20μm, 30μm, 40μm, 5μm, 60μm, 70μm, 80μm, 90μm, 100μm or 130μm, or other values ​​within the range of 3μm to 130μm.

[0064] Spherical ammonium perchlorate can reduce impact and friction sensitivity compared to non-spherical ammonium perchlorate.

[0065] Furthermore, the present invention also provides an application of the above-mentioned spherical ammonium perchlorate, for example, the spherical ammonium perchlorate can be used to prepare propellants.

[0066] Accordingly, the present invention also provides a propellant in which the oxidant comprises the aforementioned spherical ammonium perchlorate. For other components of the propellant and further applications of the propellant, please refer to the relevant prior art, which will not be elaborated upon here.

[0067] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0068] Example 1

[0069] This embodiment provides a method for preparing spherical ammonium perchlorate, including the following steps:

[0070] A supersaturated ammonium perchlorate aqueous solution containing ammonium salt was prepared by dissolving 1 g of ammonium sulfate, 5 g of ammonium perchlorate, and 20 mL of water. 200 mL of tetrachloroethylene, used as a second-phase solvent, was added to the supersaturated ammonium perchlorate aqueous solution, and ammonium perchlorate microdroplets were formed under high-speed stirring at 600 rpm. The solution was heated at 70 °C to promote the dissolution of the remaining ammonium perchlorate. While maintaining the stirring speed of 600 rpm, the solution was cooled using an ice bath at a rate of 20 °C / min to lower the temperature of the ammonium perchlorate solution below 10 °C. The solution was then allowed to stand at room temperature for 12 h. The supernatant water and the second-phase tetrachloroethylene were removed sequentially, and the solution was dried to obtain spherical ammonium perchlorate (SEM image of this spherical ammonium perchlorate is shown below). Figure 1 (As shown).

[0071] Example 2

[0072] A supersaturated ammonium perchlorate aqueous solution containing ammonium salt was prepared by mixing 1g ammonium nitrate, 10g ammonium perchlorate, and 20mL water. 400mL of tetrachloroethylene, used as a second-phase solvent, was added to the above-mentioned supersaturated ammonium perchlorate aqueous solution containing ammonium salt, and ammonium perchlorate microdroplets were formed under high-speed stirring at 600rpm. The solution was heated at 80°C to promote the dissolution of the remaining ammonium perchlorate. The stirring speed was maintained at 600rpm, and the solution was cooled using an ice bath at a rate of 30°C / min to lower the temperature of the ammonium perchlorate solution to below 10°C. The solution was then allowed to stand at room temperature for 24h. The supernatant water and the second-phase tetrachloroethylene were removed sequentially, and the solution was dried to obtain spherical ammonium perchlorate.

[0073] Example 3

[0074] A supersaturated ammonium perchlorate aqueous solution containing ammonium salt was prepared by mixing 1g ammonium chloride, 10g ammonium perchlorate, and 20mL water. 400mL of dichloromethane as the second phase solvent was added to the above supersaturated ammonium perchlorate aqueous solution containing ammonium salt, and ammonium perchlorate microdroplets were formed under high-speed stirring at 400rpm. The solution was heated at 80℃ to promote the dissolution of the remaining ammonium perchlorate. The stirring speed was maintained at 400rpm, and the solution was cooled using an ice bath at a rate of 1℃ / min to lower the temperature of the ammonium perchlorate solution to below 10℃. The solution was then allowed to stand at room temperature for 24h. The supernatant water and the second phase dichloromethane were removed sequentially, and the solution was dried to obtain spherical ammonium perchlorate.

[0075] Example 4

[0076] This embodiment provides a method for preparing spherical ammonium perchlorate, including the following steps:

[0077] A supersaturated ammonium perchlorate aqueous solution containing ammonium salt was prepared by mixing 1g ammonium sulfate, 2g ammonium perchlorate, and 7mL water. 20mL of chloroform as the second phase solvent was added to the above supersaturated ammonium perchlorate aqueous solution containing ammonium salt, and ammonium perchlorate microdroplets were formed under high-speed stirring at 800rpm. The solution was heated at 40°C to promote the dissolution of the remaining ammonium perchlorate. The stirring speed was maintained at 800rpm, and the solution was cooled using an ice bath at a rate of 20°C / min to lower the temperature of the ammonium perchlorate solution to below 10°C. The solution was then allowed to stand at room temperature for 2h. The upper layer of water and the second phase of chloroform were removed sequentially, and the solution was dried to obtain spherical ammonium perchlorate.

[0078] That is, the difference between this embodiment and Example 1 is that: the mass ratio of ammonium perchlorate to ammonium sulfate is 2:1; the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is 1:5; the second phase solvent is chloroform; the stirring speed is 800 rpm; the heating temperature is 40°C; and the standing time is 2 h.

[0079] Example 5

[0080] This embodiment provides a method for preparing spherical ammonium perchlorate, including the following steps:

[0081] A supersaturated ammonium perchlorate aqueous solution containing ammonium salt was prepared by dissolving 1 g of ammonium sulfate, 5 g of ammonium perchlorate, and 20 mL of water. 2000 mL of 1,2-dichloroethylene, used as a second-phase solvent, was added to the supersaturated ammonium perchlorate aqueous solution. The solution was stirred at 900 rpm to form ammonium perchlorate microdroplets. Heating was then performed at 90°C to promote the dissolution of the remaining ammonium perchlorate. The stirring speed was maintained at 900 rpm, and the solution was cooled using an ice bath at a rate of 20°C / min to lower the temperature of the ammonium perchlorate solution below 10°C. The solution was then allowed to stand at room temperature for 12 h. The supernatant water and the second-phase 1,2-dichloroethylene were removed sequentially, and the solution was dried to obtain spherical ammonium perchlorate (SEM image of this spherical ammonium perchlorate is shown in Figure 1). Figure 2 As shown, the particle size distribution diagram is as follows: Figure 3 (As shown).

[0082] That is, the difference between this embodiment and Embodiment 1 is that: the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is 1:100; the second phase solvent is 1,2-dichloroethylene; the stirring speed is 900 rpm; and the heating temperature is 90°C.

[0083] Comparative Example 1

[0084] The difference between this comparative example and Example 1 is that the mass ratio of ammonium perchlorate to ammonium salt is 1:1.

[0085] The EDS diagram of the ammonium perchlorate prepared in this comparative example is shown below. Figure 4 As shown.

[0086] Comparative Example 2

[0087] The difference between this comparative example and Example 1 is that the mass ratio of ammonium perchlorate to ammonium salt is 12:1.

[0088] Comparative Example 3

[0089] The difference between this comparative example and Example 1 is that the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is 1:4.

[0090] Comparative Example 4

[0091] The difference between this comparative example and Example 1 is that the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is 1:120.

[0092] Comparative Example 5

[0093] The difference between this comparative example and Example 1 is that the stirring speed is 1000 rpm.

[0094] Comparative Example 6

[0095] The difference between this comparative example and Example 1 is that no heating was performed.

[0096] Comparative Example 7

[0097] The difference between this comparative example and Example 1 is that the heating temperature is 100°C.

[0098] Comparative Example 8

[0099] The difference between this comparative example and Example 1 is that the cooling rate is 35°C / min.

[0100] Test case

[0101] The morphology and particle size of the ammonium perchlorate prepared in Examples 1-5 and Comparative Examples 1-8 were tested, and the results are shown in Table 1.

[0102] Table 1 Test Results

[0103]

[0104]

[0105] As can be seen from Table 1, the ammonium perchlorate prepared in Examples 1 to 5 of the present invention are all spherical. The particle size distribution of the ammonium perchlorate prepared in each example is relatively concentrated, the average particle size is small, the purity is high, and the product is stable.

[0106] In summary, the preparation method provided by this invention has advantages such as simple operation, controllable particle size, high safety performance, and easy product separation. The ammonium perchlorate prepared by the above method has a spherical shape, which reduces impact and friction sensitivity compared to non-spherical ammonium perchlorate. The aforementioned spherical ammonium perchlorate can be used to prepare propellants.

[0107] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing spherical ammonium perchlorate, characterized in that, Includes the following steps: A supersaturated ammonium perchlorate aqueous solution containing ammonium salt was stirred and mixed with a second phase solvent, and heated to promote the dissolution of the remaining ammonium perchlorate; while maintaining stirring and cooling, water and the second phase solvent were removed, and the remaining solid was dried. Wherein, the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is immiscible with the second phase solvent; In the supersaturated ammonium perchlorate aqueous solution containing ammonium salt, the mass ratio of ammonium perchlorate to ammonium salt is 2:1 to 10:1; the volume ratio of water to the second phase solvent in the supersaturated ammonium perchlorate aqueous solution containing ammonium salt is 1:5 to 1:100; the stirring speed is 400 rpm to 900 rpm; the heating temperature is 40℃ to 90℃; and the cooling rate is 1℃ / min to 30℃ / min.

2. The preparation method according to claim 1, characterized in that, The ammonium salt includes at least one of ammonium nitrate, ammonium sulfate, and ammonium chloride.

3. The preparation method according to claim 1, characterized in that, The second phase solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethylene, and 1,2-dichloroethylene.

4. The preparation method according to claim 1, characterized in that, After cooling, allow it to stand for a while, then remove the water and the second phase solvent.

5. The preparation method according to claim 4, characterized in that, The settling time is 2h to 24h, and / or the settling temperature is room temperature.

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