A method for recovering asphalt based on a small amount of asphalt mixture

Abstract

The present invention relates to the technical field of solid waste recovery, and proposes a method for efficiently and conveniently recovering asphalt based on a small amount of asphalt mixture, comprising the following steps: S1, taking an asphalt mixture sample, adding water and ultrasonic cleaning, washing away impurities on the sample surface; S2, placing the impurity-removed and dried sample in a mixed solvent, soaking for 20 to 40 minutes, until the aggregate shows that there is no asphalt wrapping; the mixed solvent includes 1,1-diethoxyethane and methyl tert-butyl ether; S3, taking the mixture of step S2, after vacuum filtration and centrifugation, taking the supernatant and placing it in a fume hood for preliminary volatilization, and then placing it in a blast drying oven at 60 to 105°C to evaporate the solvent, and recovering asphalt. The present invention adopts a low-boiling point solvent 1,1-diethoxyethane and methyl tert-butyl ether compound, combined with subsequent vacuum filtration, centrifugation and volatilization treatment to realize a method for efficiently and conveniently recovering asphalt from an asphalt mixture, compared with the existing Absen method and rotary evaporator method, it has the advantages of high fidelity of the recovered asphalt and no organic solvent residue.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste recycling, and in particular to a method for efficiently and conveniently recycling asphalt based on a small amount of asphalt mixture. Background Art

[0002] In recent years, researchers have paid more and more attention to the state and performance of asphalt in asphalt mixtures. They test its performance after extraction. Usually, the extracted asphalt is subjected to dynamic shear rheology test, bending beam rheology test, rotational viscosity test, etc. These tests usually require a large amount of recovered asphalt samples, which is time-consuming and labor-intensive. With the gradual deepening of research, a trend from macro to micro has been formed. The macroscopic properties of asphalt are determined by its microscopic chemical composition and structure. Many studies have shifted to the characterization and study of the microscopic properties of asphalt. Commonly used test methods include Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (NMR) and atomic force microscopy (AFM). These tests are highly accurate, easy to operate and require very few samples. Therefore, it is urgent to propose a test method for quickly and easily recovering a small amount of asphalt to serve microscopic tests.

[0003] The existing asphalt recycling method often uses the Absen method, which has the following disadvantages: the boiling points of common organic solvents such as trichloroethylene and tetrahydrofuran are high, and it is not easy to evaporate completely. In addition, it is impossible to directly judge their evaporation state during the experiment. If there is any residue, it will affect the performance of the asphalt. In addition, under the existing heating conditions (155℃~166℃), it is very easy to cause secondary aging of the recycled asphalt. The performance indicators usually detected in the recycled asphalt have large deviations and do not match the actual state. Therefore, it is urgent to propose a method for recycling asphalt with complete asphalt recovery, no solvent residue, and small error in the recovered asphalt indicators. Summary of the invention

[0004] In view of this, the present invention proposes a method for efficiently and simply recovering asphalt based on a small amount of asphalt mixture, which solves the problems of incomplete asphalt recovery, residual solvents, and large errors in the indicators of recovered asphalt in the current traditional asphalt recovery methods.

[0005] The technical solution of the present invention is implemented as follows: On the one hand, the present invention provides a method for efficiently and conveniently recovering asphalt based on a small amount of asphalt mixture, comprising the following steps:

[0006] S1, take an asphalt mixture sample, add water and perform ultrasonic cleaning to remove impurities on the sample surface;

[0007] S2, placing the impurity-removed sample in a mixed solvent and soaking it for 20 to 40 minutes until there is no asphalt attached to the surface of the aggregate; the mixed solvent includes 1,1-diethoxyethane and methyl tert-butyl ether;

[0008] S3, taking the mixed material of step S2, filtering and centrifuging under reduced pressure, taking the supernatant and placing it in a fume hood for preliminary volatilization, and then placing it in a forced air drying oven at 60-105°C to evaporate the solvent, and obtaining recovered asphalt.

[0009] 1,1-Diethoxyethane (acetal): Acetal is a medium polar ether solvent, and its main function is to dissolve polar components in asphalt. Asphalt is not a single compound, but a complex mixture of various hydrocarbons, polar compounds and colloids. Acetal can selectively dissolve polar components in asphalt. For example, polar functional groups (such as carbonyl, hydroxyl, etc.) in asphalt react with the ether oxygen atoms of acetal, thereby reducing the binding force between asphalt and mineral materials.

[0010] The ether oxygen group in the molecular structure of methyl tert-butyl ether (MTBE) provides moderate polarity, which enables it to effectively react with various components in asphalt (including non-polar components such as saturated hydrocarbons) to help desorb asphalt from the surface of the mineral material. Similarly, MTBE is highly volatile and easily evaporates after use, making it easier to handle and reduce environmental residues.

[0011] The combination of the two solvents achieves a synergistic dissolution of the polar and non-polar components in asphalt. Acetal preferentially dissolves polar components, reducing the viscosity of asphalt and its binding force with mineral materials, while MTBE dissolves non-polar components, further promoting the dissolution and separation of asphalt. This synergistic effect improves the recovery efficiency of asphalt and reduces residual asphalt. The temperature of 90-100°C is sufficient to evaporate these two low-boiling point solvents without causing significant thermal aging of the asphalt.

[0012] On the basis of the above technical solution, preferably, the volume ratio of 1,1-diethoxyethane:methyl tert-butyl ether is (9-10):(1-2).

[0013] On the basis of the above technical solution, preferably, the mixed solvent also includes 2-methyl-1,3-dioxolane.

[0014] 2-Methyl-1,3-dioxolane is a compound with properties between polar and non-polar solvents, which can dissolve a wide range of compounds. Combining it with 1,1-diethoxyethane and MTBE may enhance the overall solubility of the mixed solvent for the different components in asphalt. 2-Methyl-1,3-dioxolane also affects the surface tension of the mixed solvent, enhancing its ability to penetrate the interface between asphalt and aggregate, which helps to separate asphalt and aggregate more quickly and thoroughly.

[0015] On the basis of the above technical solution, preferably, the volume ratio of methyl tert-butyl ether:2-methyl-1,3-dioxolane is (1-2):1.

[0016] On the basis of the above technical solution, preferably, the liquid level of the mixed solvent is 1 to 2 cm higher than the highest point of the asphalt mixture.

[0017] On the basis of the above technical solution, preferably, step S2 is performed in a closed container to avoid solvent volatilization, and the solvent is heated to 30-35° C. to improve the dissolution rate.

[0018] On the basis of the above technical solution, preferably, in step S1, during ultrasonic cleaning, the temperature is set to 50-60° C. and the frequency is set to 30-40 Khz.

[0019] On the basis of the above technical solution, preferably, in step S3, the filter membrane for vacuum filtration is 0.5-1.6 μm.

[0020] On the basis of the above technical solution, preferably, in step S3, the centrifugal force is 3000-4000 rpm, the centrifugal time is 0.5-1 h, and the temperature is <35°C.

[0021] The method for efficiently and conveniently recovering asphalt based on a small amount of asphalt mixture of the present invention has the following beneficial effects compared with the prior art:

[0022] (1) The present invention adopts a compound of low-boiling-point solvent 1,1-diethoxyethane and methyl tert-butyl ether, combined with subsequent vacuum filtration, centrifugation and volatilization treatment to achieve a method for efficiently and conveniently recovering asphalt from asphalt mixture. Compared with the existing Absen method and rotary evaporator method, the present invention has the advantages of high fidelity of the recovered asphalt and no organic solvent residue.

[0023] (2) The present invention adds 2-methyl-1,3-dioxolane organic solvent to 1,1-diethoxyethane and methyl tert-butyl ether, forming three solvents with different polarities and solubility, ensuring that all components of asphalt can be efficiently dissolved and recovered, ensuring high fidelity. At the same time, 2-methyl-1,3-dioxolane also helps dissolution and evaporation at low temperatures, thereby reducing the residual organic solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is an infrared spectrum of the asphalt recovered according to the embodiment of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] The method for efficiently and conveniently recovering asphalt from a small amount of asphalt mixture in this embodiment comprises the following steps:

[0029] S1, take about 500g of AC-13 asphalt mixture sample (oil-to-stone ratio is 4.8%), put it into an ultrasonic cleaning machine, add clean water to cover the sample, set the temperature to 50℃, the frequency to 30Khz, clean for 10min, remove impurities on the sample surface and then dry.

[0030] S2, mix 1,1-diethoxyethane and methyl tert-butyl ether in a volume ratio of 10:1, and then heat to 30°C, take the dried sample in step S1 and immerse it in a mixed organic solvent. The liquid level of the mixed solvent is 1 cm higher than the highest point of the asphalt mixture, stir the asphalt mixture solution until there is no obvious asphalt coating on the aggregate surface, and seal it and let it stand for 20 minutes.

[0031] S3, pour the mixture of step S2 into a vacuum filtration device, use glass fiber filter paper with a pore size of 0.5μm as the filter medium, and the asphalt solution and mineral powder particles with a particle size of less than 0.5μm are pressed into a receiving test tube under the action of negative pressure, so as to achieve the purpose of removing most of the mineral powder particles; then put the test tube into a high-speed centrifuge, set the centrifugal force to 3000rpm, the temperature to <35℃, and after centrifugation for 0.5h, the remaining mineral powder sinks to the bottom of the test tube, completing the separation of the asphalt solution and all the mineral powder.

[0032] S4, take the upper asphalt solution after centrifugation, pour it into an open container, place it in a fume hood for 12 hours to allow the mixed solvent to evaporate initially, then transfer the container to a 60°C oven for drying for 1 hour to evaporate and remove methyl tert-butyl ether, then raise the temperature to 105°C and maintain for 1 hour to evaporate and remove 1,1-diethoxyethane; after the solvent evaporates, the recovered asphalt is obtained.

[0033] Example 2

[0034] The method for efficiently and conveniently recovering asphalt from a small amount of asphalt mixture in this embodiment comprises the following steps:

[0035] S1, take about 500g of AC-13 asphalt mixture sample (oil-to-stone ratio is 4.8%), put it into an ultrasonic cleaning machine, add clean water to cover the sample, set the temperature to 50℃, the frequency to 30Khz, clean for 10min, remove impurities on the sample surface and then dry.

[0036] S2, mix 1,1-diethoxyethane, methyl tert-butyl ether and 2-methyl-1,3-dioxolane in a volume ratio of 10:1:1, and then heat to 30°C, take the dried sample in step S1 and immerse it in a mixed organic solvent. The liquid level of the mixed solvent is 1 cm higher than the highest point of the asphalt mixture, stir the asphalt mixture solution until there is no obvious asphalt coating on the aggregate surface, and seal it and let it stand for 20 minutes.

[0037] S3, pour the mixture of step S2 into a vacuum filtration device, use glass fiber filter paper with a pore size of 0.5μm as the filter medium, and the asphalt solution and mineral powder particles with a particle size of less than 0.5μm are pressed into a receiving test tube under the action of negative pressure, so as to achieve the purpose of removing most of the mineral powder particles; then put the test tube into a high-speed centrifuge, set the centrifugal force to 3000rpm, the temperature to <35℃, and after centrifugation for 0.5h, the remaining mineral powder sinks to the bottom of the test tube, completing the separation of the asphalt solution and all the mineral powder.

[0038] S4, take the upper asphalt solution after centrifugation, pour it into an open container, place it in a fume hood for 12 hours, allow the mixed solvent to evaporate initially, then transfer the container to a 60°C oven for drying for 1 hour to evaporate and remove methyl tert-butyl ether, then continue to heat to 85°C and maintain for 1 hour to evaporate and remove 2-methyl-1,3-dioxolane, then heat to 105°C and maintain for 1 hour to evaporate and remove 1,1-diethoxyethane; after the solvent evaporates, the recovered asphalt is obtained.

[0039] Example 3

[0040] The method for efficiently and conveniently recovering asphalt from a small amount of asphalt mixture in this embodiment comprises the following steps:

[0041] S1, take about 500g of AC-13 asphalt mixture sample (oil-to-stone ratio is 4.8%), put it into an ultrasonic cleaning machine, add clean water to cover the sample, set the temperature to 55℃, the frequency to 40Khz, clean for 10 minutes, remove impurities on the sample surface and then dry.

[0042] S2, mix 1,1-diethoxyethane, methyl tert-butyl ether and 2-methyl-1,3-dioxolane in a volume ratio of 10:2:1, and then heat to 33°C, take the dried sample in step S1 and immerse it in a mixed organic solvent. The liquid level of the mixed solvent is 2 cm higher than the highest point of the asphalt mixture, stir the asphalt mixture solution until there is no obvious asphalt coating on the aggregate surface, and seal it and let it stand for 40 minutes.

[0043] S3, pour the mixture of step S2 into a vacuum filtration device, use glass fiber filter paper with a pore size of 1 μm as the filter medium, and the asphalt solution and mineral powder particles with a particle size of less than 1 μm are pressed into a receiving test tube under the action of negative pressure, so as to achieve the purpose of removing most of the mineral powder particles; then put the test tube into a high-speed centrifuge, set the centrifugal force to 3500 rpm, the temperature to <35°C, and after centrifugation for 1 hour, the remaining mineral powder sinks to the bottom of the test tube, completing the separation of the asphalt solution and all the mineral powder.

[0044] S4, take the upper asphalt solution after centrifugation, pour it into an open container, place it in a fume hood for 12 hours, allow the mixed solvent to evaporate initially, then transfer the container to a 65°C oven for drying for 1 hour to evaporate and remove methyl tert-butyl ether, then continue to heat to 85°C and maintain for 1 hour to evaporate and remove 2-methyl-1,3-dioxolane, then heat to 105°C and maintain for 1 hour to evaporate and remove 1,1-diethoxyethane; after the solvent evaporates, the recovered asphalt is obtained.

[0045] Example 4

[0046] The method for efficiently and conveniently recovering asphalt from a small amount of asphalt mixture in this embodiment comprises the following steps:

[0047] S1, take about 500g of AC-13 asphalt mixture sample (oil-to-stone ratio is 4.8%), put it into an ultrasonic cleaning machine, add clean water to cover the sample, set the temperature to 60℃, the frequency to 35Khz, clean for 10 minutes, remove impurities on the sample surface and then dry.

[0048] S2, mix 1,1-diethoxyethane, methyl tert-butyl ether and 2-methyl-1,3-dioxolane in a volume ratio of 10:1.5:1, and then heat to 35°C, take the dried sample in step S1 and immerse it in a mixed organic solvent. The liquid level of the mixed solvent is 2 cm higher than the highest point of the asphalt mixture, stir the asphalt mixture solution until there is no obvious asphalt coating on the aggregate surface, and seal it and let it stand for 30 minutes.

[0049] S3, pour the mixture of step S2 into a vacuum filtration device, use glass fiber filter paper with a pore size of 1.6μm as the filter medium, and the asphalt solution and mineral powder particles with a particle size less than 1.6μm are pressed into a receiving test tube under the action of negative pressure, so as to achieve the purpose of removing most of the mineral powder particles; then put the test tube into a high-speed centrifuge, set the centrifugal force to 4000rpm, the temperature to <35℃, and after centrifugation for 50min, the remaining mineral powder sinks to the bottom of the test tube, completing the separation of the asphalt solution and all the mineral powder.

[0050] S4, take the upper asphalt solution after centrifugation, pour it into an open container, and place it in a fume hood for 12 hours to allow the mixed solvent to evaporate initially, evaporate and remove methyl tert-butyl ether, then continue to heat to 85°C and maintain for 1 hour to evaporate and remove 2-methyl-1,3-dioxolane, then heat to 105°C and maintain for 1 hour to evaporate and remove 1,1-diethoxyethane; after the solvent evaporates, the recovered asphalt is obtained.

[0051] Example 5

[0052] The method for efficiently and conveniently recovering asphalt from a small amount of asphalt mixture in this embodiment comprises the following steps:

[0053] S1, take about 500g of AC-13 asphalt mixture sample (oil-to-stone ratio is 4.8%), put it into an ultrasonic cleaning machine, add clean water to cover the sample, set the temperature to 60℃, the frequency to 35Khz, clean for 10 minutes, remove impurities on the sample surface and then dry.

[0054] S2, mix 1,1-diethoxyethane, methyl tert-butyl ether and 2-methyl-1,3-dioxolane in a volume ratio of 9:1:1, and then heat to 35°C. Take the dried sample in step S1 and immerse it in a mixed organic solvent. The liquid level of the mixed solvent is 1.5 cm higher than the highest point of the asphalt mixture. Stir the asphalt mixture solution until there is no obvious asphalt coating on the aggregate surface. Seal and let it stand for 35 minutes.

[0055] S3, pour the mixture of step S2 into a vacuum filtration device, use glass fiber filter paper with a pore size of 1 μm as the filter medium, and the asphalt solution and mineral powder particles with a particle size of less than 1 μm are pressed into a receiving test tube under the action of negative pressure, so as to achieve the purpose of removing most of the mineral powder particles; then put the test tube into a high-speed centrifuge, set the centrifugal force to 4000 rpm, the temperature to <35°C, and after centrifugation for 1 hour, the remaining mineral powder sinks to the bottom of the test tube, completing the separation of the asphalt solution and all the mineral powder.

[0056] S4, take the upper asphalt solution after centrifugation, pour it into an open container, place it in a fume hood for 12 hours, allow the mixed solvent to evaporate initially, then transfer the container to a 65°C oven for drying for 1 hour to evaporate and remove methyl tert-butyl ether, then continue to heat to 85°C and maintain for 1 hour to evaporate and remove 2-methyl-1,3-dioxolane, then heat to 105°C and maintain for 1 hour to evaporate and remove 1,1-diethoxyethane; after the solvent evaporates, the recovered asphalt is obtained.

[0057] Example 6

[0058] The method for efficiently and conveniently recovering asphalt from a small amount of asphalt mixture in this embodiment comprises the following steps:

[0059] S1, take about 500g of AC-13 asphalt mixture sample (oil-to-stone ratio is 4.8%), put it into an ultrasonic cleaning machine, add clean water to cover the sample, set the temperature to 58°C and the frequency to 40Khz, clean for 10 minutes, remove impurities on the sample surface and then dry.

[0060] S2, mix 1,1-diethoxyethane, methyl tert-butyl ether and 2-methyl-1,3-dioxolane in a volume ratio of 9:1.5:1, and then heat to 35°C, take the dried sample in step S1 and immerse it in a mixed organic solvent. The liquid level of the mixed solvent is 2 cm higher than the highest point of the asphalt mixture, stir the asphalt mixture solution until there is no obvious asphalt coating on the aggregate surface, and seal it and let it stand for 40 minutes.

[0061] S3, pour the mixture of step S2 into a vacuum filtration device, use glass fiber filter paper with a pore size of 1.6μm as the filter medium, and the asphalt solution and mineral powder particles with a particle size less than 1.6μm are pressed into a receiving test tube under the action of negative pressure, so as to achieve the purpose of removing most of the mineral powder particles; then put the test tube into a high-speed centrifuge, set the centrifugal force to 4000rpm, the temperature to <35℃, and after centrifugation for 1h, the remaining mineral powder sinks to the bottom of the test tube, completing the separation of the asphalt solution and all the mineral powder.

[0062] S4, take the upper asphalt solution after centrifugation, pour it into an open container, place it in a fume hood for 12 hours, allow the mixed solvent to evaporate initially, then transfer the container to a 65°C oven for drying for 1 hour to evaporate and remove methyl tert-butyl ether, then continue to heat to 85°C and maintain for 1 hour to evaporate and remove 2-methyl-1,3-dioxolane, then heat to 105°C and maintain for 1 hour to evaporate and remove 1,1-diethoxyethane; after the solvent evaporates, the recovered asphalt is obtained.

[0063] Comparative Example 1

[0064] Compared with Example 1, Comparative Example 1 lacks methyl tert-butyl ether, and the rest of the contents are the same.

[0065] Comparative Example 2

[0066] Compared with Example 1, Comparative Example 2 lacks 1,1-diethoxyethane and is replaced by methyl tert-butyl ether. The rest of the contents are the same.

[0067] Comparative Example 3

[0068] Compared with Example 1, in Comparative Example 3, the volume ratio of 1,1-diethoxyethane:methyl tert-butyl ether is 2:1.

[0069] Comparative Example 4

[0070] In Comparative Example 4 compared with Example 2, the volume ratio of 1,1-diethoxyethane:2-methyl-1,3-dioxolane:methyl tert-butyl ether is 10:3:2.

[0071] Comparative Example 5

[0072] Comparative Example 5 Compared with Example 1, trichloroethylene is used as a solvent to dissolve and elute the asphalt mixture, and the Absen method is adopted. The specific steps are: according to the Absen method, the upper layer of asphalt solution after centrifugation is adjusted to a heating temperature in a reaction container to make the solution flow out, and when the solution temperature reaches 128°C, a protective gas with a flow rate of 300mL / min is introduced for the first time; when the solution temperature reaches 158°C, the protective gas introduction amount is increased to 1600mL / min, and the temperature and the protective gas introduction amount are maintained for 10min until the distillation is completed; when the solvent of the distilled filtrate is condensed into a liquid, and distilled until no liquid drips at the condensation point, the recovered asphalt is obtained after delayed heating for 1h.

[0073] The untreated base asphalt of Example 1, the asphalt mortar made by mixing the base asphalt and the mineral powder, and the asphalt recovered in Example 1 were subjected to infrared spectroscopy tests to obtain infrared spectral curves of the base asphalt, the asphalt mortar, and the recovered asphalt, respectively. The results are shown in FIG. Figure 1 .

[0074] Infrared spectrum experiments can clearly show the composition of the measured substances, and the experimental results are intuitive and reliable. Figure 1 It can be seen that the infrared spectrum curve of the asphalt mortar composed of base asphalt and mineral powder is very different from that of the base asphalt. The characteristic peak of the mineral powder appears at a wave number of 873 cm -1 The blue curve is the asphalt recovered by using Example 1 of the present invention, and its curve is basically coincident with the base asphalt, and no characteristic peak of mineral powder appears, which indicates that the present invention can effectively separate mineral powder, remove solvent, and obtain real and effective recovered asphalt.

[0075] The asphalt recovered from the examples and comparative examples was tested, wherein the needle penetration (25°C, 100 g, 5 s), softening point TR&B, 10°C elongation and 135°C rotational viscosity were measured in accordance with JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering", and the results are shown in Table 1.

[0076] Table 1 Performance of recovered asphalt of the present invention

[0077]

[0078] As shown in Table 1, the performance of the asphalt obtained by the recovery method of the present invention is not much different from that of the asphalt in the initial mixture, indicating that the recovered asphalt has high fidelity, no aging, and no solvent residue. The Absen method uses a higher temperature, which causes the asphalt to age and affects the performance of the asphalt. This proves that the compounding of 1,1-diethoxyethane, 2-methyl-1,3-dioxolane and methyl tert-butyl ether can achieve the technical effect of high-fidelity recovery of asphalt.

[0079] The amount of asphalt recovered in the examples and comparative examples was tested to verify the extraction rate of the solvent. The results are shown in Table 2.

[0080] Table 2 Solvent Extractability

[0081]

[0082] In Table 2, it can be seen from the data of Examples 1 to 2 and Comparative Examples 1 to 2 that the compounding of 1,1-diethoxyethane, 2-methyl-1,3-dioxolane and methyl tert-butyl ether ensures that all components of asphalt can be efficiently dissolved and recovered, thereby improving the efficiency of recovering asphalt.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for recovering asphalt based on a small amount of asphalt mixture, characterized in that: The following steps are involved: S1, take an asphalt mixture sample, add water and perform ultrasonic cleaning to remove impurities on the sample surface; S2, placing the impurity-removed and dried sample in a mixed solvent and soaking it for 20 to 40 minutes until there is no asphalt attached to the surface of the aggregate; the mixed solvent includes 1,1-diethoxyethane and methyl tert-butyl ether; The volume ratio of 1,1-diethoxyethane:methyl tert-butyl ether is (9-10):(1-2); S3, taking the mixed material of step S2, filtering and centrifuging under reduced pressure, taking the supernatant and placing it in a fume hood for preliminary volatilization, and then placing it in a forced air drying oven at 60-105°C to evaporate the solvent, and obtaining recovered asphalt.

2. A method for recovering asphalt based on a small amount of asphalt mixture as claimed in claim 1, characterized in that: The mixed solvent also includes 2-methyl-1,3-dioxolane.

3. A method for recovering asphalt based on a small amount of asphalt mixture as claimed in claim 2, characterized in that: The volume ratio of the methyl tert-butyl ether:2-methyl-1,3-dioxolane is (1-2):

1.

4. A method for recovering asphalt based on a small amount of asphalt mixture as claimed in claim 1, characterized in that: The liquid level of the mixed solvent is 1 to 2 cm higher than the highest point of the asphalt mixture.

5. A method for recovering asphalt based on a small amount of asphalt mixture as claimed in claim 1, characterized in that: Step S2 is carried out in a closed container, and the solvent is heated to 30-35°C.

6. A method for recovering asphalt based on a small amount of asphalt mixture as claimed in claim 1, characterized in that: In step S1, during ultrasonic cleaning, the temperature is set to 50-60°C and the frequency is set to 30-40Khz.

7. A method for recovering asphalt based on a small amount of asphalt mixture as claimed in claim 1, characterized in that: In step S3, the filter membrane for vacuum filtration is 0.5 to 1.6 μm.

8. A method for recovering asphalt based on a small amount of asphalt mixture as claimed in claim 1, characterized in that: In step S3, the centrifugal force is 3000-4000 rpm, the centrifugal time is 0.5-1 h, and the temperature is <35°C.

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