Asphalt microspheres and methods and apparatus for making same

Abstract

The present application relates to a kind of asphalt microspheres and its preparation method and device, the preparation method includes, melt asphalt is formed under the action of pressure continuous jet, then form asphalt droplet by nozzle under the action of vibration;Asphalt droplet falls and is cooled and solidified in cooling medium, obtain asphalt microspheres.The present application is cut into the droplet of size height uniform by nozzle with the help of jet breaking mechanism cooperation vibration continuous jet of melt asphalt, continuous jet of melt asphalt is cut into the droplet of size height uniform;Droplet spontaneously shrinks into spherical shape by its surface tension, the sphericity of finished product asphalt microspheres is ≥95%, particle size distribution standard deviation is ≤0.10, compared with traditional spray granulation process, particle size dispersity is significantly reduced.Compared with gravity natural drop mode (close vibration), particle size distribution standard deviation is reduced by 84%, and spheroidization rate is increased by 49%.

Description

Technical Field

[0001] This invention relates to the field of asphalt microsphere technology, specifically to an asphalt microsphere and its preparation method and apparatus. Background Technology

[0002] Spherical activated carbon, as a high-performance adsorbent, has broad application prospects in gas separation, solvent recovery, catalyst support, and medical protection. The preparation of spherical activated carbon from asphalt first requires the asphalt to be prepared into spherical precursors; therefore, the spheroidization process of the asphalt directly determines the performance of the final spherical activated carbon.

[0003] Currently, there are three main methods for making asphalt pellets: (1) Disc granulation method: Asphalt powder is rolled into balls in a disc granulator. This method has simple equipment, but the asphalt microspheres produced have rough surfaces, low strength, and large diameters (usually greater than 1 mm), which makes it difficult to meet the particle size requirements of high-performance spherical activated carbon for the precursor.

[0004] (2) Emulsification method: Asphalt and emulsifier are heated and stirred in a high-pressure autoclave to form an emulsion, which is then cooled to precipitate asphalt microspheres. This method has strict requirements on the softening point of the asphalt raw material, requires pre-modification of the asphalt, and the obtained asphalt microspheres need to be extracted by solvent before subsequent pre-oxidation treatment. The process is long and the equipment cost is high. At the same time, the extraction process generates a large amount of organic wastewater, which causes serious environmental pollution.

[0005] (3) Spraying method: Molten asphalt is sprayed into a cooling tower through a nozzle and cooled into spheres. This method requires the construction of a cooling tower that is usually more than 10 meters high. Otherwise, the molten asphalt will not stay in the air for long enough, which will easily cause the asphalt microspheres to stick together. At the same time, the nozzle structure is complex and the cooling process will generate a large amount of exhaust gas containing asphalt fumes, which is difficult to treat and costly.

[0006] Some studies have also achieved continuous preparation of pitch microspheres by combining melt spinning technology. For example, CN111960408A discloses an efficient method for preparing mesophase pitch carbon microspheres, which involves uniformly mixing mesophase pitch with a plasticizer, then placing it in the barrel of a spinning machine, and forming "bead-like" pitch droplets through melt spinning process adjustment; subsequently, the extruded pitch droplets are directly dripped into an aqueous receiver, and obtained asphalt microspheres after filtration, washing, and drying. However, a large amount of plasticizer needs to be added. Summary of the Invention

[0007] The purpose of this invention is to achieve the continuous preparation of millimeter-sized asphalt microspheres from pure asphalt melt through active vibration via a nozzle and direct cooling under zero additive conditions.

[0008] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing asphalt microspheres, comprising, Molten asphalt is formed into a continuous jet under pressure, and then formed into asphalt droplets through a nozzle under vibration. After falling, the asphalt droplets are cooled and solidified in a cooling medium to obtain asphalt microspheres.

[0009] Furthermore, the pressure is 0.05-0.15 MPa; the vibration frequency is 500-700 Hz.

[0010] Furthermore, the nozzle orifice diameter is 0.25-0.40 mm.

[0011] Furthermore, the distance between the asphalt droplets and the cooling medium is 8-15 cm.

[0012] Furthermore, the molten asphalt is obtained by heating asphalt at a temperature 30-50°C above its softening point.

[0013] Furthermore, the softening point of the asphalt is 100-150℃.

[0014] Furthermore, the temperature of the cooling medium is 15-30°C.

[0015] The present invention also provides asphalt microspheres, which are obtained by the above-described preparation method. The asphalt microspheres have a particle size of 0.2-0.5 mm, a sphericity ≥95%, a sphericity ≥95%, and a particle size distribution standard deviation ≤0.10.

[0016] The present invention also provides an apparatus for preparing asphalt microspheres, including a pressure supply component, a heating vessel, a heat preservation component, a vibrator, a nozzle, and a cooling component; The pressure supply component is connected to the heating vessel and is used to provide pressure to the heating vessel; The heating vessel is used to melt asphalt; The insulation component is used to insulate the molten asphalt and provide a place for the molten asphalt under pressure to form a continuous jet. The vibrator is disposed on the outside of the heat insulation component and is used to apply vibration to the continuous jet. The nozzle is connected to the bottom of the vibrator; The cooling component is located below the nozzle, and the cooling component stores a cooling medium.

[0017] Furthermore, the pressure supply component provides pressure to the heating vessel in the form of gas.

[0018] Furthermore, the heat-insulating component includes a heat-tracing corrugated pipe and an electric heat-tracing insulation layer covering the outside of the heat-tracing corrugated pipe.

[0019] Compared with the prior art, the beneficial effects of the present invention include: (1) This invention utilizes the jet fracture mechanism combined with vibration to pass a continuous jet of molten asphalt through a nozzle, cutting the continuous jet of molten asphalt into droplets of uniform size and height. The droplets spontaneously shrink into spherical shapes due to their own surface tension. The sphericity of the finished asphalt microspheres is ≥95%, and the standard deviation of particle size distribution is ≤0.10. Compared with the traditional spray granulation process, the particle size dispersion is significantly reduced. Compared with gravity natural dripping (with vibration off), the standard deviation of particle size distribution is reduced by 84%, and the sphericity rate is increased by 49%.

[0020] (2) This invention eliminates the need for plasticizers or other additives during the preparation process, reducing the risk of adding additives that decompose and volatilize during subsequent carbonization / graphitization, leaving microporous defects inside the microspheres and reducing the mechanical strength and graphitization degree of the carbon microspheres. It fundamentally eliminates the dependence on plasticizers and avoids the deterioration of product performance caused by additive residues.

[0021] (3) The preparation process of the present invention does not require the addition of emulsifiers, extractants and other organic additives and chemical reagents. The production process does not generate organic waste liquid, asphalt fumes and solid hazardous waste, and the pollutants are zero-emission.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0024] Figure 1 A schematic diagram of the apparatus for preparing asphalt microspheres according to the present invention is shown; Figure 2 A flowchart of the method for preparing asphalt microspheres according to the present invention is shown; Figure 3 A polarized light microscope image of the pitch microspheres prepared in Example 1 is shown; Figure 4 A statistical diagram of the particle size distribution of the asphalt microspheres prepared in Example 1 is shown; Explanation of reference numerals in the attached figures: 1. Heating vessel; 2. Corrugated heating pipe; 3. Electric heating insulation layer; 4. Vibrator; 5. Nozzle; 6. Cooling water tank. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] Low yield, difficulty in controlling size, and microsphere adhesion have long been bottlenecks in the production and application of asphalt microspheres. Current improvement methods mainly involve introducing plasticizers or other additives into molten asphalt, which improves the uniformity and yield of asphalt microspheres. However, because these additives decompose and volatilize during subsequent carbonization / graphitization, they leave microporous defects inside the microspheres, reducing the mechanical strength and graphitization degree of the carbon microspheres. This leads to a decrease in the performance of other products prepared by carbonization using asphalt microspheres as raw materials. This not only increases the production cost but also makes it difficult to control the performance of the resulting products.

[0029] Therefore, this invention is proposed.

[0030] On one hand, the present invention provides a method for preparing pitch microspheres, comprising, Molten asphalt is formed into a continuous jet under pressure, and then formed into asphalt droplets through a nozzle under vibration. After falling, the asphalt droplets are cooled and solidified in a cooling medium to obtain asphalt microspheres.

[0031] This invention eliminates the need for any additives during the melting of asphalt. The molten asphalt forms a continuous jet under pressure. Periodic lateral disturbances are applied to the continuous jet of molten asphalt under vibration, causing the jet to break into independent droplets uniformly. The droplets spontaneously contract into spherical shapes due to surface tension and are ejected from the nozzle. Subsequently, they are cooled and solidified in a cooling medium, thus achieving rapid and continuous preparation of asphalt microspheres with high sphericity.

[0032] In some preferred embodiments, the pressure is 0.05-0.15 MPa; the vibration frequency is 500-700 Hz. The pressure can be achieved by introducing a gas, which is a non-oxidizing or inert gas, preferably nitrogen.

[0033] In some preferred embodiments, the nozzle orifice has a diameter of 0.25-0.40 mm.

[0034] In some preferred embodiments, the distance between the asphalt droplets and the cooling medium is 8-15 cm. It should be noted that the present invention does not strictly limit the type of cooling medium; any liquid with a high specific heat capacity, that does not react with asphalt, and that is inexpensive and readily available is acceptable. Preferably, it can be water.

[0035] In some preferred embodiments, the molten asphalt is obtained by heating asphalt at its softening point temperature of 30-50°C.

[0036] In some preferred embodiments, the softening point of the asphalt is 100-150°C. If the softening point of the asphalt is too low, the carbon residue will be low, resulting in poor integrity of the subsequent microspheres; if the softening point of the asphalt is too high, the fluidity will be too poor.

[0037] In some preferred embodiments, the temperature of the cooling medium is 15-30°C.

[0038] The present invention will be further described in detail below through specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0039] Example 1 like Figure 1 As shown, an apparatus for preparing asphalt microspheres includes a pressure supply component ( Figure 1The system comprises a heating vessel 1 (not shown), a heat-insulating component, a vibrator 4, a nozzle 5, and a cooling water tank 6. A pressure supply component is connected to the heating vessel 1 to provide pressure to it. The heating vessel 1 is used to melt asphalt. The heat-insulating component includes a heat-tracing corrugated pipe 2 and an electric heat-tracing insulation layer 3 covering the outside of the heat-tracing corrugated pipe 2. The electric heat-tracing insulation layer 3 heats the heat-tracing corrugated pipe 2 to keep the molten asphalt warm, and the molten asphalt under pressure forms a continuous jet in the heat-tracing corrugated pipe 2. The vibrator 4 is located outside the electric heat-tracing insulation layer 3 and is used to apply vibration to the continuous jet in the heat-tracing corrugated pipe 2. The nozzle 5 is rigidly connected to the bottom of the vibrator 4. The cooling water tank 6 is located 5-15 cm below the nozzle 5 and contains room-temperature deionized water as a single-phase cooling medium.

[0040] The pressure supply component can be a gas cylinder, which is equipped with a pressure gauge and stores nitrogen gas. The opening of the gas cylinder is controlled to adjust the pressure acting on the molten asphalt in the heating kettle.

[0041] Vibrator 4 can be a piezoelectric vibrator.

[0042] The following embodiments and comparative examples are all implemented using the apparatus of this embodiment, and the specific apparatus structure will not be described in detail.

[0043] Example 2 like Figure 2 As shown, a method for preparing asphalt microspheres includes the following steps: Step 1: Place the asphalt raw material with a softening point of 120℃ into a high-speed blender and crush it. Take 50g of asphalt powder and add it to the heating kettle.

[0044] Step 2: Turn on the heating vessel and set the heating temperature to 150℃. When the temperature of the heating vessel reaches 130℃, turn on the switch of the electric heat tracing insulation layer and set the heat tracing temperature to 130℃.

[0045] Step 3: Open the gas cylinder pressure relief valve and introduce nitrogen gas into the heating vessel at a pressure of 0.1 MPa. Observe the pressure inside the heating vessel, and open the exhaust valve to release the gas after the pressure rises.

[0046] Step 4: When asphalt dripping is observed at the nozzle, turn on the vibrator and adjust the vibration frequency to 600Hz. Continuously introduce nitrogen gas to maintain the pressure inside the heating vessel at 0.1MPa. Under pressure, the molten asphalt is ejected in a continuous jet form from the nozzle with an orifice diameter of 0.3mm under vibration.

[0047] Step 5: The sprayed asphalt droplets fall directly into the cooling water tank below the nozzle. The distance between the water in the cooling water tank and the nozzle (referred to as the cooling distance) is 10cm. The droplets are rapidly cooled and solidified in the 20℃ water.

[0048] Step 6: After the reaction is complete, separate the asphalt microspheres from the cooling water with gauze and allow them to dry naturally at room temperature for 12 hours.

[0049] Step 7: The dried asphalt microspheres are sieved using 20-mesh, 40-mesh, and 60-mesh standard sieves to collect asphalt microsphere products with different particle size ranges.

[0050] like Figure 3 As shown, sphericity was determined using a polarizing microscope image statistical method, and the sphericity rate of 1000 randomly selected microspheres was statistically analyzed. Particle size distribution was determined using a laser particle size analyzer, and the results are as follows. Figure 4 As shown in the figure. The test results show that the particle diameter range is 0.20-0.50 mm, the average particle size is 0.32 mm, the sphericity is 97%, the sphericity rate is 97%, and the standard deviation of particle size distribution is 0.07.

[0051] Example 3 Compared with Example 2, the differences are as follows: in Step 1, the softening point of the asphalt raw material is 100℃; in Step 2, the heating temperature of the heating kettle is set to 135℃, and when the temperature of the heating kettle reaches 100℃, the switch of the electric heat tracing insulation layer is turned on, and the heat tracing temperature is set to 135℃; in Step 4, the vibration frequency is 500Hz, and the orifice diameter of the nozzle is 0.4mm; in Step 5, the cooling distance is 12cm.

[0052] The performance of the asphalt microspheres obtained in this embodiment was tested. The test results showed that the sphere diameter ranged from 0.30 to 0.50 mm, the average particle size was 0.38 mm, the sphericity was 95%, the sphericity rate was 96%, and the standard deviation of particle size distribution was 0.08.

[0053] Compared to Example 2, in Example 3, the aperture was increased from 0.3 mm to 0.4 mm, resulting in a larger critical perturbation wavelength and a lower required breakage frequency. Therefore, the frequency was reduced from 600 Hz to 500 Hz. Simultaneously, the increased aperture led to a larger droplet mass and increased kinetic energy upon entering the water, necessitating an extended cooling distance of 12 cm to ensure sufficient time for droplet spheroidization in the air. These three parameters exhibit a synergistic adjustment relationship.

[0054] Example 4 Compared with Example 2, the differences are as follows: in Step 1, the softening point of the asphalt raw material is 125℃; in Step 2, the heating temperature of the heating kettle is set to 165℃, and when the temperature of the heating kettle reaches 105℃, the switch of the electric heat tracing insulation layer is turned on, and the heat tracing temperature is set to 165℃; in Step 4, the vibration frequency is 700Hz, and the orifice diameter of the nozzle is 0.25mm; in Step 5, the cooling distance is 8cm.

[0055] The performance of the asphalt microspheres obtained in this embodiment was tested. The test results showed that the sphere diameter ranged from 0.20 to 0.35 mm, the average particle size was 0.28 mm, the sphericity was 96%, the sphericity rate was 97%, and the standard deviation of particle size distribution was 0.06.

[0056] Compared to Example 2, in Example 4, the aperture was reduced from 0.3 mm to 0.25 mm, resulting in a smaller critical perturbation wavelength and a higher required breakage frequency. Therefore, the frequency was increased from 600 Hz to 700 Hz. The smaller aperture also reduced the droplet volume and shortened the sphericification time in air, thus reducing the cooling distance to 8 cm. These adjustments followed the synergistic principle that aperture and frequency change in opposite directions, while cooling distance and aperture change in the same direction.

[0057] Example 5 Compared with Example 2, the differences are as follows: in Step 1, the softening point of the asphalt raw material is 135℃; in Step 2, the heating temperature of the heating kettle is set to 175℃, and when the temperature of the heating kettle reaches 115℃, the switch of the electric heat tracing insulation layer is turned on, and the heat tracing temperature is set to 175℃; in Step 4, the vibration frequency is 650Hz, and the orifice diameter of the nozzle is 0.35mm; in Step 5, the cooling distance is 15cm.

[0058] The performance of the asphalt microspheres obtained in this embodiment was tested. The test results showed that the sphere diameter ranged from 0.25 to 0.45 mm, the average particle size was 0.35 mm, the sphericity was 95%, the sphericity rate was 95%, and the standard deviation of particle size distribution was 0.08.

[0059] Compared to Example 2, Example 5 increased the aperture from 0.3 mm to 0.35 mm, and the softening point of the asphalt increased from 120°C to 135°C (increased viscosity). Both require stronger disturbance energy to achieve complete jet breakage, so the frequency increased from 600 Hz to 650 Hz. The increased aperture requires extending the cooling distance to 15 cm to ensure sufficient spheroidization, but 15 cm is close to the upper limit of the effective cooling distance determined by this invention.

[0060] Table 1 summarizes the vibration frequency, nozzle orifice diameter, and cooling distance for Examples 1-5.

[0061] Table 1

[0062] The aforementioned tests show that the sphericity of the asphalt microspheres obtained in Examples 1-5 is ≥95%, and the standard deviation of particle size distribution is ≤0.10, indicating that the asphalt microsphere preparation method provided by this invention has wide process adaptability. Within an effective range of parameter combinations, when conditions such as pore size and softening point change, asphalt microsphere products with high sphericity and uniform particle size distribution can be prepared by adjusting the process parameters according to the synergistic law of inverse coupling between pore size and frequency and unidirectional adjustment between cooling distance and pore size.

[0063] Comparative Examples 1-3 Compared with Example 2, the difference is that the orifice diameters of the nozzles are 0.2mm, 0.4mm and 0.5mm, respectively.

[0064] Table 2 summarizes the droplet morphology, sphericity, and standard deviation of particle size distribution of the resulting asphalt microspheres in Example 2 and Comparative Examples 1-3 during the preparation process.

[0065] Table 2

[0066] The results in Table 2 show that at a fixed frequency of 600Hz and a cooling distance of 10cm, only a 0.3mm aperture can produce a qualified product, while other apertures have obvious defects.

[0067] Comparative Examples 4-8 Compared with Example 2, the difference is that the vibration frequencies are 0Hz (no vibration), 300Hz, 400Hz, 800Hz, and 900Hz.

[0068] Table 3 summarizes the droplet morphology, sphericity, and standard deviation of particle size distribution of the resulting asphalt microspheres in Example 2 and Comparative Examples 4-8 during the preparation process.

[0069] Table 3

[0070] The results in Table 3 show that, under a fixed orifice diameter of 0.3 mm and a cooling distance of 10 cm, without vibration (Comparative Example 4), the molten asphalt naturally undergoes Rayleigh-Platto instability fracture solely due to gravity and surface tension. The jet fracture points are completely random, and the droplets exhibit uneven gourd-like / beaded shapes with a significantly larger average particle size. The sphericity is only 35%, and the standard deviation of the particle size distribution is as high as 0.65. When a low-frequency vibration of 300 Hz is applied (Comparative Example 5), due to the excessively long perturbation wavelength, it cannot match the jet's optimal growth frequency. The perturbation energy is input into the jet at an incorrect frequency, which inhibits the natural fracture rhythm of the jet, resulting in more disordered droplet breaking behavior. The sphericity is only 58%, still not achieving the ideal sphericity effect. When the frequency is increased to 400 Hz (Comparative Example 6), the droplet breaking is somewhat improved, but some areas still do not complete the fracture. The sphericity increases to 73%, but it is still not ideal.

[0071] The above results indicate that the vibration frequency must match the intrinsic frequency of the jet fracture to effectively exert the jet modulation effect. Under the preferred parameter combination of this invention (0.3mm aperture, 10cm cooling distance), the preferred vibration frequency range is 500-700Hz. Within this range, qualified products with a spheroidization rate ≥95% and a particle size distribution standard deviation ≤0.10 can be stably obtained. When the vibration frequency deviates from this effective range (below 500Hz or above 700Hz), uniform jet fracture cannot be achieved, the low-frequency disturbance effect is poor, and excessively high frequencies will cause droplets to be too small, adhere, or produce a large number of satellite droplets, which will also lead to a significant decrease in spheroidization rate.

[0072] Example 6 The difference compared to Example 2 is that the cooling distance is 15cm.

[0073] Comparative Examples 9-11 The difference compared to Example 2 is that the cooling distances are 3cm, 5cm and 20cm respectively.

[0074] Table 4 summarizes the droplet morphology, sphericity, and standard deviation of particle size distribution of the resulting asphalt microspheres in Examples 2, 6, and Comparative Examples 9-11 during the preparation process.

[0075] Table 4

[0076] The results in Table 4 show that, with a fixed aperture of 0.3 mm and a vibration frequency of 600 Hz, a cooling distance of 5-15 cm is required to obtain qualified products. A cooling distance that is too short will severely affect the spheroidization rate, while a cooling distance that is too long will increase adhesion.

[0077] Comparative Example 12 Unlike Example 2, which uses a vibrator to apply vibration to the continuous jet, this example uses probe vibration as described in CN107029640A to disturb the continuous jet.

[0078] The performance of the asphalt microspheres obtained in this comparative example was tested. The test results showed that due to the inconsistent location of the jet fracture and large fluctuations in droplet size, the sphericity was only 81%, the sphericity was only 76%, and the standard deviation of particle size distribution was 0.28. This is far inferior to the vibration disturbance of Example 2 (sphericity 97%, sphericity 97%, standard deviation of particle size distribution 0.07).

[0079] Based on the absence of additives and the high sphericity and uniform particle size distribution, the asphalt microspheres prepared by this invention have the following industrial application prospects: (1) Spherical activated carbon precursor: The pitch microspheres prepared in this invention can be directly used to prepare high-performance spherical activated carbon after pre-oxidation, carbonization and activation, which can be used in gas separation, solvent recovery, catalyst support, medical protection and other fields.

[0080] (2) High-density isotropic graphite raw materials: Pitch microspheres have self-sintering properties. After molding, carbonization and graphitization, high-density isotropic graphite materials can be prepared for use in semiconductor manufacturing, electrical discharge machining and other fields.

[0081] (3) Lithium-ion battery anode material: After carbonization, pitch microspheres have high specific capacity and good cycle stability, and can be used as a high-quality precursor for lithium-ion battery anode materials.

[0082] Overall, the method for preparing asphalt microspheres of the present invention has a clear route, controllable operation, simple and compact equipment (no need for high-altitude cooling tower), short batch processing time, and is suitable for large-scale industrial production.

[0083] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing asphalt microspheres, characterized in that, include, Molten asphalt is formed into a continuous jet under pressure, and then formed into asphalt droplets through a nozzle under vibration. After falling, the asphalt droplets are cooled and solidified in a cooling medium to obtain asphalt microspheres.

2. The method for preparing pitch microspheres according to claim 1, characterized in that, The frequency of the vibration is 500-700Hz; The nozzle has an orifice diameter of 0.25-0.40 mm. The distance between the asphalt droplets and the cooling medium is 8-15 cm.

3. The method for preparing pitch microspheres according to claim 1, characterized in that, The pressure is 0.05-0.15 MPa.

4. The method for preparing pitch microspheres according to claim 1, characterized in that, The molten asphalt is obtained by heating asphalt at a temperature 30-50°C above its softening point.

5. The method for preparing pitch microspheres according to claim 4, characterized in that, The softening point of the asphalt is 100-150℃.

6. The method for preparing pitch microspheres according to claim 4, characterized in that, The temperature of the cooling medium is 15-30℃.

7. A kind of asphalt microsphere, characterized in that, The asphalt microspheres are prepared by any one of claims 1-6, and have a particle size of 0.2-0.5 mm, a sphericity ≥95%, a sphericity ≥95%, and a particle size distribution standard deviation ≤0.

10.

8. An apparatus for preparing asphalt microspheres, characterized in that, It includes pressure supply components, heating vessel, heat preservation components, vibrator, nozzles, and cooling components; The pressure supply component is connected to the heating vessel and is used to provide pressure to the heating vessel; The heating vessel is used to melt asphalt; The insulation component is used to insulate the molten asphalt and provide a place for the molten asphalt under pressure to form a continuous jet. The vibrator is disposed on the outside of the heat insulation component and is used to apply vibration to the continuous jet. The nozzle is connected to the bottom of the vibrator; The cooling component is located below the nozzle, and the cooling component stores a cooling medium.

9. The apparatus for preparing asphalt microspheres according to claim 8, characterized in that, The pressure supply component provides pressure to the heating vessel in the form of gas.

10. The apparatus for preparing pitch microspheres according to claim 8, characterized in that, The heat-insulating component includes a heat-tracing corrugated pipe and an electric heat-tracing insulation layer covering the outside of the heat-tracing corrugated pipe.

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