Asphalt shoveling material handling method

Abstract

The present disclosure provides a method for processing asphalt millings, comprising: (a) providing asphalt millings, wherein the asphalt millings comprise a plurality of aggregate and asphalt coating the aggregate; and (b) performing an asphalt stripping process on the asphalt millings, wherein the asphalt in the asphalt millings is at least partially separated from the aggregate by an asphalt stripping unit using water as a medium.

Description

Technical Field

[0001] This disclosure relates to methods for treating asphalt scraping material, particularly low-energy methods that enable the recycling of asphalt and aggregates. Background Technology

[0002] Asphalt has become the mainstream material for road paving worldwide. With the growing global awareness of sustainable development, the recycling and reuse of reclaimed asphalt pavement (RAP) generated in road construction has become an important issue. RAP mainly consists of aggregate and aged asphalt mortar covering its surface. The aggregate includes crushed stone, sand, and gravel.

[0003] Traditional asphalt recycling methods often use chemical technologies such as organic solvents and thermal cracking to process asphalt scrap and extract asphalt. However, while existing chemical technologies can separate asphalt from aggregates, they often require operation under complex conditions and additional recovery agent procedures, resulting in high energy consumption, making them difficult to commercialize and inconsistent with current sustainable and environmental trends.

[0004] Therefore, developing low-energy-consumption processing technologies that can efficiently separate asphalt to realize the resource utilization of asphalt scrap is an urgent issue that the industry needs to address. Summary of the Invention

[0005] This disclosure relates to a method for treating asphalt stripping material, for example, separating asphalt and aggregate in the asphalt stripping material through a pretreatment unit and an asphalt stripping unit, and further screening out recycled stone and asphalt sand through a water circulation screening unit.

[0006] According to some embodiments, this disclosure provides a method for treating asphalt stripping material. The method includes the following steps: (a) providing an asphalt stripping material, wherein the asphalt stripping material includes a plurality of aggregates and asphalt covering the aggregates; and (b) performing an asphalt stripping treatment on the asphalt stripping material, wherein the asphalt in the asphalt stripping material is at least partially separated from the aggregates by means of an asphalt stripping unit using water as a medium.

[0007] In one embodiment of the aforementioned asphalt removal material treatment method, it further includes:

[0008] Prior to step (b), the asphalt scraper is pretreated, wherein a biological agent is applied to the asphalt scraper by a pretreatment unit to form a first product.

[0009] In one embodiment of the aforementioned asphalt stripping material treatment method, it further includes: in step (b), using the asphalt stripping unit with water as a medium, separating at least part of the asphalt in the first product from the plurality of aggregates, and forming a second product.

[0010] In one embodiment of the aforementioned asphalt removal material treatment method, it further includes:

[0011] (c) The second product is subjected to a vibratory screening process by a water circulation screening unit to separate a third product and a fourth product, wherein the third product contains a plurality of bituminous sands and the fourth product contains a plurality of recycled stones.

[0012] In one embodiment of the aforementioned asphalt removal material treatment method, the water circulation screening treatment unit includes a screening machine, a cyclone separator, a fine sand screening machine, a sedimentation tank, and a filter press dewatering machine.

[0013] In one embodiment of the aforementioned asphalt stripping material treatment method, the screening machine receives a first mixture after the asphalt stripping treatment. The first mixture contains the asphalt, the plurality of aggregates, and water. The screening machine separates the first mixture into a mixture containing the third product and a mixture containing the fourth product. The average particle size of the mixture containing the third product is less than 3 mm, and the average particle size of the mixture containing the fourth product is greater than or equal to 3 mm.

[0014] In one embodiment of the aforementioned asphalt removal material treatment method, the mixture containing the third product is further provided to the cyclone separator, and the second mixture containing particles with an average particle size of less than 0.075 mm is collected by the cyclone separator and placed in the sedimentation tank for settling to form precipitate.

[0015] In one embodiment of the aforementioned asphalt stripping material treatment method, the precipitate is further introduced into a filter press dewatering machine for pressing to remove moisture, and the supernatant in the sedimentation tank after settling is returned to the asphalt stripping unit for reuse.

[0016] In one embodiment of the aforementioned asphalt removal material treatment method, when the total weight of the plurality of asphalt sands is 100 wt%, the asphalt content is greater than 6 wt%.

[0017] In one embodiment of the aforementioned asphalt removal material treatment method, when the total weight of the plurality of recycled stones is 100 wt%, the asphalt content is less than 1 wt%.

[0018] In one embodiment of the aforementioned asphalt removal material treatment method, the plurality of recycled stones includes a first group of recycled stones, the average particle size of the first group of recycled stones being greater than or equal to 10 mm, and the asphalt content being less than 0.2 wt% when the total weight of the first group of recycled stones is 100 wt%.

[0019] In one embodiment of the aforementioned asphalt removal material treatment method, the plurality of recycled stones includes a second group of recycled stones, the average particle size of the second group of recycled stones being 3 mm to 10 mm, and the asphalt content being less than 1 wt% when the total weight of the second group of recycled stones is 100 wt%.

[0020] In one embodiment of the aforementioned asphalt removal material treatment method, the bacterial species of the biological agent include bacteria belonging to the genus Bacillus, bacteria belonging to the genus Priestia, or a combination thereof.

[0021] In one embodiment of the aforementioned asphalt removal material treatment method, the bacteria belonging to the genus Bacillus include Bacillus velezensis, Bacillus subtilis, Bacillus toyonensis, Bacillus licheniformis, Bacillus paralicheniformis, Bacillus thuringiensis, Bacillus pumilus, or a combination thereof. The bacteria belonging to the genus Priestia include Priestia aryabhattai, Priestia megaterium, Priestia flexa, Priestia filamentosa, Priestia endophytica, or a combination thereof.

[0022] In one embodiment of the aforementioned asphalt scraping material treatment method, the biological agent acts on the asphalt scraping material in the form of a bacterial solution. The weight ratio of the bacterial solution to the asphalt scraping material is between 0.001 and 1, and the concentration (OD) of the bacterial solution is... 600 The value is between 1 and 3.

[0023] In one embodiment of the aforementioned asphalt scraping material treatment method, the asphalt scraping material has a first asphalt viscosity before the application of the biological agent, and the first product has a second asphalt viscosity, wherein the second asphalt viscosity is less than the first asphalt viscosity.

[0024] In one embodiment of the aforementioned asphalt stripping material treatment method, in step (b), the asphalt stripping process is carried out in a drum reactor.

[0025] In one embodiment of the aforementioned asphalt removal material treatment method, the rotational tangential velocity of the drum reactor is between 0.5 m / s and 2.5 m / s.

[0026] In one embodiment of the aforementioned asphalt stripping material treatment method, in step (b), the reaction temperature of the asphalt stripping treatment is between 20°C and 100°C.

[0027] In one embodiment of the aforementioned asphalt stripping material treatment method, in step (b), the reaction time of the asphalt stripping treatment is between 20 minutes and 130 minutes.

[0028] To provide a better understanding of the above and other aspects of this disclosure, specific embodiments are described below in conjunction with the accompanying drawings: Attached Figure Description

[0029] Figure 1A The diagram illustrates a step-by-step flowchart of an asphalt removal material treatment method according to an embodiment of the present disclosure.

[0030] Figure 1B The illustration shows a schematic diagram of asphalt sand and recycled stone produced by an asphalt removal material treatment method according to an embodiment of the present disclosure.

[0031] Figure 1C The illustration shows a schematic diagram of treating asphalt with a biological agent according to an embodiment of the present disclosure.

[0032] Figure 2 The diagram illustrates a schematic representation of an asphalt removal material treatment system according to an embodiment of this disclosure; and

[0033] Figure 3 The illustration shows a water circulation screening and processing unit comprising processing components for performing screening, separation and other procedures, according to an embodiment of the present disclosure.

[0034] In the attached figures, the following labels are used:

[0035] 10: Preprocessing Unit

[0036] 20: Asphalt stripping unit

[0037] 30: Water circulation screening and treatment unit

[0038] 31: Screening machine

[0039] 33: Cyclone Separator

[0040] 35: Fine Sand Screening Machine

[0041] 37: Sedimentation tank

[0042] 39: Filter press dewatering machine

[0043] AG: Aggregate

[0044] AS: Asphalt

[0045] ASN: Asphalt

[0046] BIO: Biological Agent

[0047] RAP: Asphalt Removal Material

[0048] S11~S17: Steps

[0049] SG1: Asphalt Sand

[0050] SG2: Regenerated Stone

[0051] SY: Asphalt Removal Material Processing System

[0052] WR:water Detailed Implementation

[0053] The following description, in conjunction with the accompanying drawings, details various embodiments. It should be understood that the description and drawings are provided for illustrative purposes only and are not intended to be limiting. For clarity, some components and / or symbols may be omitted in some drawings. Furthermore, components in the drawings may not be drawn to scale. It is anticipated that components and features in one embodiment can be advantageously incorporated into another embodiment without further repetition.

[0054] In this text, the phrase "the range is between the first value and the second value" means that the range includes the first value, the second value, and other values ​​in between.

[0055] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It is understood that these terms, for example, as defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the relevant art and the background or context of this disclosure, and should not be interpreted in an idealized or overly formal manner, unless specifically defined in the embodiments of this disclosure.

[0056] Figure 1A The illustration shows a flowchart of the steps of a method for treating reclaimed asphalt pavement (RAP) according to an embodiment of the present disclosure. Figure 1B The illustration shows a schematic diagram of asphalt sand SG1 and recycled stone SG2 produced by the asphalt removal material RAP treatment method according to an embodiment of the present disclosure. Figure 1C The illustration shows a schematic diagram of treating asphalt sludge (ASN) in asphalt scraper material (RAP) with the biological agent BIO, according to an embodiment of this disclosure.

[0057] The method of this embodiment includes sequential steps S11 to S17. It should be understood that the method may also include other steps and techniques, or some steps may be omitted.

[0058] Please refer to both 1A and Figure 1B As shown in step S11, asphalt removal material RAP is provided. The asphalt removal material RAP includes aggregate AG and asphalt AS covering the surface of the aggregate AG. The aggregate AG may include sand and gravel, such as sand and gravel with inconsistent particle size and irregular shape.

[0059] As shown in step S13, the asphalt removal material RAP undergoes a pretreatment process, wherein a pretreatment unit 10 (such as...) is used to... Figure 2 As shown, a biological agent (BIO) is applied to asphalt scraper material (RAP) to form a first product. This step can be carried out at room temperature. The room temperature range can be from 15°C to 35°C, for example, from 20°C to 30°C, or about 18°C, 20°C, 22°C, 25°C, 28°C, 30°C, 32°C, etc., but this disclosure is not limited to this.

[0060] According to some embodiments, the bio-initiator BIO can be a microorganism screened from environmental samples, and can be a single species or a mixed species. The species can include bacteria belonging to the genus *Bacillus*, bacteria belonging to the genus *Priestia*, or a combination of the foregoing. Bacteria belonging to the genus *Bacillus* can include, but are not limited to, *Bacillus velezensis* (BV), *Bacillus subtilis*, *Bacillus toyonensis*, *Bacillus licheniformis*, *Bacillus paralicheniformis*, *Bacillus thuringiensis*, and *Bacillus pumilus*. Bacteria belonging to the genus *Priestia* include, but are not limited to, *Priestia aryabhattai* (PA), *Priestia megaterium*, *Priestia flexa*, *Priestia filamentosa*, and *Priestia endophytica*. It should be understood that the bio-initiator BIO disclosed herein is not limited to these. The *Bacillus* species of the bio-initiator BIO can produce endospores, exhibit thermostable characteristics during its dormant period, and can tolerate temperatures ranging from 60°C to 90°C. The biosafety level of the bio-initiator BIO is Risk group 1 (RG1), meaning that the known risk to human, animal, and plant health and the environment is the lowest level.

[0061] Please refer to Figure 1C In asphalt shaving aggregate (RAP), the asphalt asphalt (AS) consists of asphaltenes (ASN). As the asphalt asphalt ages, the content of asphaltenes (ASN) increases, and the degree of cross-linking improves, leading to an increase in the viscosity of the asphalt asphalt. By adding the bio-initiator BIO to the aged asphalt asphalt, the bio-initiator BIO secretes surfactants (not shown) to emulsify the asphaltenes (ASN), thus decomposing the asphaltenes (AS) and reducing its viscosity (i.e., reducing the bond strength between the asphalt asphalt and aggregate AG).

[0062] For example, the asphalt removal material RAP has a first asphalt viscosity before step S13, and the first product formed after step S13 has a second asphalt viscosity, which is less than the first asphalt viscosity. According to one embodiment, the percentage reduction of the second asphalt viscosity from the first asphalt viscosity can be equal to or greater than 2%, for example, equal to or greater than 5%, equal to or greater than 10%, etc., or for example, between 10% and 40%, for example, between 15% and 35%, between 20% and 40%, etc., but this disclosure is not limited thereto.

[0063] According to some embodiments, the bio-agent BIO acts on the asphalt scraper (RAP) in the form of a bacterial solution, with a weight ratio of bacterial solution to asphalt scraper between 0.001 and 1 (i.e., a weight ratio of bacterial solution to asphalt between 0.2 and 30), for example, between 0.005 and 0.9, or between 0.01 and 0.8, but this disclosure is not limited thereto. On the other hand, the concentration of the bacterial solution (optical density, OD)... 600 The value can be between 1 and 3, for example, between 1.2 and 2.5, or between 1.2 and 1.4, but this disclosure is not limited thereto.

[0064] Please refer again to section 1A and... Figure 1B As shown in step S15, the first product undergoes an asphalt stripping process, wherein an asphalt stripping unit 20 (e.g., ...) is used to remove asphalt. Figure 2 (As shown) Using water as a medium, at least partially separates the asphalt AS from the aggregate AG in the first product (i.e., the asphalt stripping material RAP after step S13, comprising asphalt AS and aggregate AG) to form a second product. The term "at least partially separated" may mean that at least 50%, at least 65%, at least 75%, at least 80%, or at least 90% of the total asphalt AS is separated from the aggregate AG, but this disclosure is not limited thereto.

[0065] According to one embodiment of the bitumen stripping process disclosed herein, water is used directly as the medium without the addition of any organic solvents, making it very environmentally friendly. The water used in this disclosure may be, for example, reverse osmosis water, deionized water, distilled water, mineral water, tap water, or other suitable water.

[0066] Specifically, asphalt stripping unit 20 (such as...) Figure 2(As shown) Aqueous phase-assisted separation technology is used, in which the first product is immersed in water and given a driving force. That is, no organic solvents are used, but water is used as a carrier to cause collisions between the asphalt stripping material (RAP), thereby achieving the separation of asphalt (AS) and aggregate (AG). For example, asphalt stripping is carried out in a drum reactor.

[0067] Since one embodiment of this disclosure uses a drum reactor for asphalt stripping instead of a vertical reactor that requires blade rotation, it can be mass-produced and is commercially feasible.

[0068] According to some embodiments, in asphalt stripping treatment, the rotational tangential velocity of the drum reactor can be between 0.5 m / s and 2.5 m / s, for example, between 0.75 m / s and 2.45 m / s, between 0.80 m / s and 2.4 m / s, or for example, between 0.82 m / s and 2.2 m / s, or between 0.86 m / s and 2.35 m / s, but this disclosure is not limited thereto. The reaction temperature can be between 20°C and 100°C, for example, between 30°C and 95°C, between 40°C and 95°C, between 50°C and 95°C, between 70°C and 95°C, between 90°C and 95°C, etc., but this disclosure is not limited thereto. The reaction time can be between 20 minutes and 130 minutes, for example, between 30 minutes and 120 minutes, between 40 minutes and 110 minutes, between 50 minutes and 100 minutes, between 60 minutes and 90 minutes, etc., but this disclosure is not limited to this.

[0069] As shown in step S17, the water circulation screening treatment unit 30 (e.g.) Figure 2 As shown, the second product (i.e., the asphalt removal material RAP after step S15, including asphalt AS and aggregate AG) is subjected to a vibratory screening step to separate a third product and a fourth product, wherein the third product contains multiple asphalt sands SG1 and the fourth product contains multiple recycled stone SG2.

[0070] According to some embodiments, the average particle size of asphalt sand SG1 can be less than 3 mm, for example, 2 mm, 1.5 mm, 1 mm, etc., but this disclosure is not limited to this. On the other hand, based on the total weight of asphalt sand SG1 (i.e., considered as 100 wt%), the content of asphalt AS can be greater than 6 wt%, for example, 6.5 wt%, 7 wt%, 8 wt%, etc., but this disclosure is not limited to this. The average particle size of recycled stone SG2 can be equal to or greater than 3 mm, for example, 3.5 mm, 4 mm, 5 mm, etc., but this disclosure is not limited to this. On the other hand, based on the total weight of recycled stone SG2 as 100 wt%, the content of asphalt AS can be less than 1 wt%, for example, 0.75 wt%, 0.5 wt%, 0.25 wt%, etc., but this disclosure is not limited to this.

[0071] The recycled stone SG2 may include a first group of recycled stone, the average particle size of which may be greater than 10 mm, for example, 11 mm, 12 mm, 13 mm, etc., but this disclosure is not limited thereto. On the other hand, when the total weight of the first group of recycled stone is 100 wt%, the content of asphalt AS may be less than 0.2 wt%, for example, 0.15 wt%, 0.1 wt%, 0.05 wt%, etc., but this disclosure is not limited thereto.

[0072] The recycled stone SG2 may also include a second group of recycled stone, the average particle size of which may be 3 mm to 10 mm, for example, 5 mm, 7 mm, 9 mm, etc., but this disclosure is not limited thereto. On the other hand, when the total weight of the second group of recycled stone is 100 wt%, the content of asphalt AS may be less than 1 wt%, for example, 0.75 wt%, 0.5 wt%, 0.25 wt%, etc., but this disclosure is not limited thereto.

[0073] Since the water circulation screening and treatment unit 30 may include a screening machine 31, a cyclone separator 33, a fine sand screening machine 35, a sedimentation tank 37, and a filter press dewatering machine 39 (e.g., Figure 3 As shown in the figure (details below), step S17 may also include the following steps (i) to (iii):

[0074] (i) The screening machine 31 receives a first mixture after asphalt stripping treatment, the first mixture containing asphalt AS, aggregate AG and water WR, and the screening machine 31 screens the first mixture into a mixture containing a third product and a mixture containing a fourth product, wherein the average particle size of the mixture containing the third product is less than 3 mm, and the average particle size of the mixture containing the fourth product is greater than or equal to 3 mm.

[0075] (ii) The mixture containing the third product is further fed into a cyclone separator 33 and circulated with a fine sand screener 35 to collect a second mixture containing particles with an average particle size of less than 0.075 mm into a sedimentation tank 37 for settling to form a precipitate (a portion of the third product).

[0076] (iii) The sediment is introduced into the filter press dewatering machine 39, squeezed to remove water, and the supernatant in the sedimentation tank 37 after settling is returned to the asphalt stripping unit for reuse.

[0077] According to other embodiments, the asphalt stripping material (RAP) treatment method disclosed herein may omit step S13 (not shown). That is, step S15 is performed immediately after step S11, directly stripping the asphalt from the RAP. The asphalt stripping unit 20 uses water as a medium to separate at least part of the asphalt AS in the RAP from the aggregate AG, without undergoing the pretreatment shown in step S13. Processing steps S15 and S17 are the same as described above, and will not be repeated hereafter.

[0078] Figure 2 The illustration shows an embodiment of the asphalt removal material treatment system SY, for example, for performing the steps shown in Figures 1A-1C. Figure 3 A water circulation screening and processing unit 30 according to an embodiment of the present disclosure is illustrated.

[0079] Please refer to Figure 2 The asphalt stripping material processing system SY may include a pretreatment unit 10, an asphalt stripping unit 20, and a water circulation screening unit 30. The pretreatment unit 10 is configured to apply a biological agent BIO to the asphalt stripping material RAP to form a first product. The asphalt stripping unit 20 is connected to the pretreatment unit 10 and the water circulation screening unit 30, and is configured to receive the first product, perform an asphalt stripping treatment on the first product using water as a medium, to at least partially separate the asphalt AS in the first product from the aggregate AG, and form a second product. The water circulation screening unit 30 is configured to receive the second product (i.e., the asphalt AS and aggregate AG after asphalt stripping treatment), and perform a vibratory screening step on the second product to separate a third product and a fourth product. The third product contains multiple asphalt sands SG1, and the fourth product contains multiple recycled aggregates SG2. The water WR generated by the water circulation screening unit 30 can be transferred back to the asphalt stripping unit 20 for use in the asphalt stripping treatment. It is evident that the water WR in the water circulation screening and treatment unit 30 can be 100% reused, which conforms to the concept of sustainable utilization.

[0080] Please refer to Figure 3The water circulation screening and treatment unit 30 may include a screening machine 31, a cyclone separator 33, a fine sand screening machine 35, a sedimentation tank 37, and a filter press dewatering machine 39.

[0081] According to one embodiment of this disclosure, the screening machine 31 can receive a first mixture after asphalt stripping treatment. The first mixture contains asphalt (AS), aggregate (AG), and water (WR). The screening machine 31 separates the first mixture into a mixture containing a third product and a mixture containing a fourth product. The average particle size of the mixture containing the third product is less than 3 mm, and the average particle size of the mixture containing the fourth product is greater than or equal to 3 mm. The cyclone separator 33 can operate in cyclical operation with the fine sand screening machine 35 to collect particles with a particle size between 0.075 mm and 3 mm, and simultaneously collect particles with a particle size less than 0.075 mm to a sedimentation tank 37 for settling to the bottom. For example, the cyclone separator 33 can collect a second mixture containing particles with an average particle size less than 0.075 mm to the sedimentation tank 37 for settling to form a precipitate (a portion of the third product). The sediment is squeezed by a filter press 39 to remove water, while the clear supernatant (e.g., water WR) in the sedimentation tank 37 after settling is returned to the asphalt stripping unit 20 for recycling.

[0082] To make the above and other objects, features, and advantages of the present invention more apparent and understandable, several embodiments are described in detail below:

[0083] 1. Impact assessment of the pretreatment unit - biological agents

[0084] To test the effect of bio-initiators on the viscosity of asphalt, the following experiments were conducted in comparison with examples and comparative examples. It should be noted that although the following experiments use Bacillus velezensis (BV) and / or Priestia aryabhattai (PA) as representative microbial species in the bio-initiators, this is not a limitation. Users can choose suitable single or mixed microbial species according to their needs, and the mixing ratio of mixed microbial species can also be adjusted according to actual requirements.

[0085] 1-1 Experiment 1

[0086] Example 1 shows asphalt treated with a biological agent containing Bacillus velezensis (BV). The concentration of the bacterial solution used (OD) is... 600 The concentration of the bacterial solution was 1.2 to 1.4, and the weight ratio of the bacterial solution to the asphalt was approximately 2.86 (i.e., weight of bacterial solution: weight of asphalt = 2.86:1). Comparative Example 1 was raw asphalt, untreated with the biological agent.

[0087] Example 1 and Comparative Example 1 were treated at room temperature (25°C) for 1 to 7 days. During this period, the asphalt viscosity of Example 1 and Comparative Example 1 was tested on each day (standard measurement method followed ASTM D4402). The percentage reduction in asphalt viscosity was calculated from the test results of Example 1 and Comparative Example 1 using the following formula:

[0088] Formula 1

[0089] In Equation 1, V0 represents the initial viscosity of the asphalt in Comparative Example 1, V1 represents the viscosity of the asphalt in Example 1 after treatment with the biological agent for 1 to 7 days, and VP represents the percentage reduction in asphalt viscosity. The analytical results are shown in Table 1.

[0090] Table 1

[0091]

[0092] As shown in Table 1, the use of a single strain of BV can reduce the viscosity of asphalt, and the viscosity reduction effect can reach 10% on the 3rd day of reaction, and the viscosity reduction effect is greater than 10% on the 4th to 7th days.

[0093] Experiment 2 (1-2)

[0094] Both Examples 2-1 and 2-2 involve asphalt treated with biological agents. The biological agent in Example 2-1 used *Bacillus velezensis* (BV), while the biological agent in Example 2-2 used *Priestia aryabhattai* (PA). The concentration of the bacterial solution used (OD)... 600 The concentration of the bacterial solution was 1.2 to 1.4, and the weight ratio of the bacterial solution to the asphalt was approximately 8.3 (i.e., weight of bacterial solution: weight of asphalt = 8.3:1). Comparative Example 2 was raw asphalt, which was not treated with the biological agent.

[0095] As for the processing temperature, asphalt viscosity test, and calculation of the percentage reduction in asphalt viscosity used in Experiment 2, they were all performed in a similar manner to those in Experiment 1, and will not be repeated here.

[0096] After one week of treatment, the percentage reduction in asphalt viscosity of Examples 2-1 and 2-2 relative to Comparative Example 2 is shown in Table 2.

[0097] Table 2

[0098]

[0099] As shown in Table 2, using a single bacterial strain, whether BV or PA, resulted in a significant reduction in asphalt viscosity of nearly 20% to nearly 30% after one week.

[0100] Experiment 3 (1-3)

[0101] Examples 3-1, 3-2, and 3-3 are asphalt treated with different biological agents. The biological agent in Example 3-1 contains *Bacillus velezensis* (BV), the biological agent in Example 3-2 contains *Priestia aryabhattai* (PA), and the biological agent in Example 3-3 is a mixed strain composed of *Bacillus velezensis* (BV) and *Priestia aryabhattai* (PA) in a 1:1 ratio. The concentration of the bacterial solution used (OD)... 600 The concentration of the bacterial solution was 1.2 to 1.4, and the weight ratio of the bacterial solution to the asphalt was approximately 3.75 (i.e., weight of bacterial solution: weight of asphalt = 3.75:1). Comparative Example 3 was raw asphalt, untreated with the bacterial agent.

[0102] As for the processing temperature, asphalt viscosity test, and calculation of the percentage reduction in asphalt viscosity used in Experiment 3, they were all performed in a similar manner to those in Experiment 1, and will not be repeated here.

[0103] After one month of treatment, the percentage reduction in asphalt viscosity of Examples 3-1, 3-2, and 3-3 relative to Comparative Example 3 is shown in Table 3.

[0104] Table 3

[0105]

[0106] As shown in Table 3, whether using a single microbial strain (BV or PA) or a mixture of BV and PA, both strains significantly reduced asphalt viscosity by at least 20% or even more than 30% after one month.

[0107] On the other hand, the contents (%) of the four components in the asphalt of Comparative Example 3-1 (treated with a single strain of BV) and the asphalt of Comparative Example 3 are shown in Table 4. The viscosity of the four components, from lowest to highest, is saturates, aromatics, resins, and asphaltenes.

[0108] Table 4

[0109]

[0110] As shown in Table 4, compared with Comparative Example 3, the asphalt of Example 3-1, after reacting with the bacterial solution, showed a decrease in the proportion of high-viscosity asphaltenes and an increase in the proportion of low-viscosity saturated hydrocarbons, thus achieving the effect of reducing viscosity characteristics.

[0111] Experiment 4 (1-4)

[0112] Example 4 involves asphalt scraping material treated with a biological agent containing Bacillus velezensis (BV) for one month (as shown in steps S11 and S13), followed by asphalt stripping treatment (as shown in step S15), and then its asphalt content was tested. Comparative Example 4 involves using the original asphalt scraping material (as shown in step S11), undergoing asphalt stripping treatment (as shown in step S15), and then testing its asphalt content. The difference between Comparative Example 4 and Example 4 is that Comparative Example 4 did not undergo biological agent treatment (i.e., it did not undergo step S13).

[0113] The original asphalt removal material (RAP) had an asphalt content (i.e., the percentage of asphalt based on the total weight of the RAP, 100%) of 4.35% and an asphalt viscosity of 300,000 poise (Poise, P, 1 P = 1 g / (cm·s)). The bacterial solution used in Example 4 was a single-species BV, with a bacterial solution weight ratio of 0.0125 to the asphalt removal material (i.e., bacterial solution weight: asphalt removal material weight = 1:80), a bacterial solution weight ratio of 0.286 to the asphalt (i.e., bacterial solution weight: asphalt weight = 1:3.5), and a bacterial solution concentration (OD600) of 1.6 to 2. The particle size of the RAP tested in Comparative Example 4 was consistent with that in Example 4.

[0114] In the subsequent asphalt stripping treatment, the asphalt stripping materials from Comparative Example 4 and Example 4 were added to the reactor, along with water, and the temperature was maintained at 90°C to 93°C for a reaction time of 30 minutes. After the asphalt stripping treatment was completed, the asphalt content of Comparative Example 4 and Example 4 was measured, as shown in Table 5.

[0115] Table 5

[0116]

[0117] As shown in Table 4, compared to Comparative Example 4, the asphalt content of Example 4 decreased more significantly after undergoing asphalt stripping treatment under the same conditions. Furthermore, the asphalt viscosity measured in Example 4 was 200,000 poise (Poise, P, 1 P = 1 g / (cm·s)), and the percentage reduction in asphalt viscosity calculated using Equation 1 above was approximately 33%.

[0118] Furthermore, the asphalt stripping rate SR of Comparative Example 4 and Example 4 after asphalt stripping treatment was calculated using the following formula 2.

[0119] Formula 2

[0120] In Equation 2, C0 represents the asphalt content of the original asphalt stripping material RAP, and C1 represents the residual amount of asphalt after asphalt stripping treatment.

[0121] Calculations showed that the asphalt removal rate of Comparative Example 4 was approximately 54%, while that of Example 4 was approximately 72%. Example 4 improved the asphalt removal efficiency by at least 18% compared to Comparative Example 4, demonstrating that biological agent treatment can enhance the asphalt removal effect.

[0122] 2. Effects of different reaction conditions on asphalt stripping units

[0123] Experiment 5, 2-1

[0124] In Examples 5-1 to 5-4, the feed consisted of asphalt stripping material (RAP) of different particle sizes (as shown in step S11). The asphalt was directly processed by the asphalt stripping unit 20 (as shown in step S15) and the water circulation screening unit 30 without passing through the pretreatment unit 10 (as shown in step S13). The effect of different particle sizes on the stripping effect was tested.

[0125] In Examples 5-1 to 5-4, the weight of the asphalt removal material was 60 kg, and the asphalt content was 4% to 5.5%. The particle size of the asphalt removal material in Example 5-1 was between 100 mm and 120 mm; the particle size of the asphalt removal material in Example 5-2 was between 50 mm and 100 mm; the particle size of the asphalt removal material in Example 5-3 was between 9.5 mm and 25 mm; and the particle size of the asphalt removal material in Example 5-4 was less than 9.5 mm.

[0126] First, the asphalt stripping materials from Examples 5-1 to 5-4 are added to a reactor (e.g., a drum reactor) for asphalt stripping treatment (as in step S15). The reactor is filled with water and the reaction proceeds under specific conditions. The reaction temperatures for Examples 5-1, 5-2, and 5-4 are between 90°C and 100°C, and the reactor's tangential rotation speed is 0.86 m / s. The reaction temperature for Example 5-3 is approximately 70°C, and the reactor's tangential rotation speed is 2.3 m / s. The reaction times for Examples 5-1 to 5-4 are 120 minutes, 90 minutes, 90 minutes, and 60 minutes, respectively.

[0127] Next, the asphalt stripping material after asphalt stripping treatment is screened and separated into first-group recycled stone, second-group recycled stone, and asphalt sand with different particle sizes. The particle size of the first-group recycled stone is approximately 12.5 mm, the particle size of the second-group recycled stone is approximately 4.75 mm and 9.52 mm, and the particle size of the asphalt sand is approximately 1.18 mm and 2.36 mm.

[0128] The bitumen content of Examples 5-1 to 5-4 is shown in Table 6, where “-” indicates no data.

[0129] Table 6

[0130]

[0131] As shown in Table 6, the asphalt content of Examples 5-1 to 5-4 decreased significantly after asphalt stripping treatment, indicating that different feed particle sizes all have asphalt stripping effects.

[0132] 2-2 Experiment 6

[0133] Examples 6-1 to 6-3 show the asphalt content of asphalt stripping material RAP after being treated at different reaction temperatures by the asphalt stripping unit 20 (as shown in step S15), demonstrating the effect of reaction temperature on the stripping effect.

[0134] In Examples 6-1 to 6-3, the weight of the asphalt shavings was 60 kg, the feed particle size was between 9.5 mm and 25 mm, the asphalt content was between 4% and 5.5%, the tangential rotational speed of the reactor was 2.3 m / s, and the reaction time was 90 minutes. The reaction temperatures in Examples 6-1 to 6-3 were 90°C to 100°C, 70°C, and room temperature (e.g., 20°C to 25°C), respectively. Subsequent sieving steps, including particle size distribution, were performed as described above.

[0135] The bitumen content of Examples 6-1 to 6-3 is shown in Table 7. "-" indicates no data is available.

[0136] Table 7

[0137]

[0138] As shown in Table 7, after asphalt stripping treatment (step S15), the asphalt content in Examples 6-1 to 6-3 decreased significantly, indicating that different reaction temperatures all have an asphalt stripping effect. In particular, the asphalt stripping effect is better when the reaction temperature is equal to or greater than 70°C.

[0139] Experiment 7 (2-3)

[0140] Examples 7-1 to 7-3 show the asphalt content of asphalt stripping material RAP after asphalt stripping treatment (as shown in step S15) under different rotational tangential speed conditions, demonstrating the effect of rotational tangential speed on the stripping effect.

[0141] In Examples 7-1 to 7-3, the weight of the asphalt removal material was 60 kg, the feed particle size was between 9.5 mm and 25 mm, the asphalt content was 4-5.5%, the reaction time was 30 minutes, and the reaction temperature was 90-100°C. The rotational tangential velocities in Examples 7-1 to 7-3 were 2.3 m / s, 1.8 m / s, and 0.86 m / s, respectively. Subsequent sieving and particle size division were performed as described above.

[0142] The bitumen content of Examples 7-1 to 7-3 is shown in Table 8. "-" indicates that no data is available.

[0143] Table 8

[0144]

[0145] As shown in Table 8, after asphalt stripping treatment, the asphalt content of Examples 7-1 to 7-3 decreased significantly. In particular, the asphalt stripping effect was better with the greater the rotational tangential speed.

[0146] It should be understood that the above parameter settings (such as reaction temperature and tangential velocity) and product particle size will be adjusted according to the actual operational needs of the field.

[0147] In a prior art (e.g., reference JP5979532B2), asphalt stripping material (RAP) undergoes primary treatment (using a heated pulverizing device at a reaction temperature of 100°C), followed by asphalt extraction via a first-stage treatment unit (reaction temperature 60°C to 90°C), a second-stage treatment unit (reaction temperature 60°C to 90°C), and a third-stage treatment unit (reaction temperature 100°C to 300°C). The heated pulverizing device is a vertical reactor, and processing is carried out using blade agitation. The resulting asphalt stripping efficiency is approximately 80% to 85%. In another prior art, asphalt stripping material (RAP) is treated only by physical methods (e.g., heated pulverizing) without biological agent treatment, resulting in an asphalt stripping efficiency of approximately 50% to ~75%. According to the asphalt stripping method disclosed herein (e.g.... Figure 1A As shown in the figure, the asphalt stripping efficiency can reach >92%. It can be seen that compared with the existing technology, the asphalt stripping method disclosed in this paper can not only significantly improve the stripping efficiency, but also retain good particle size and shape of the obtained product, which can be used directly, and water resources can be recycled, which is quite environmentally friendly.

[0148] By means of processing asphalt according to some embodiments of this disclosure, the resulting recycled aggregate (e.g., asphalt content less than 1 wt.%, particle size greater than 3 mm) is tested to meet the relevant quality requirements of new grade or recycled coarse aggregate (standard measurement methods follow American Society for Testing and Materials standards ASTM-D692M-15 and ASTM-C33), and can be used as a grading material for asphalt concrete (AC) and cement concrete (RC) aggregate sources.

[0149] In the application of asphalt concrete, the recycled stone of one embodiment of this disclosure can be used together with asphalt sand as graded aggregate, and a 100% recycling rate can be achieved. Asphalt concrete specimens that meet the requirements can be successfully prepared, showing that the product obtained by the method disclosed in this disclosure has the benefits of increasing the resource utilization ratio of excavated material, reducing the amount of natural aggregate used, and reducing the flow of waste.

[0150] In the application of cement concrete, this disclosure discloses an embodiment of using recycled stone to replace coarse aggregate; under the condition of maintaining the same compressive strength, the amount of cementitious material can be reduced by about 1% to 25%. Therefore, it can not only reduce the cost of cementitious materials and carbon emissions, but also improve the technical effect of resource recycling efficiency.

[0151] On the other hand, the asphalt sand obtained in one embodiment of this disclosure (e.g., asphalt content greater than 9 wt%, particle size less than 3 mm) has a high asphalt content and can therefore be directly used as a recycled gradation material for asphalt concrete. The asphalt sand can be directly reused in pavement material preparation and repaving projects. Since the asphalt sand contains usable asphalt, it can be used to mix asphalt concrete, thereby reducing the demand for new asphalt, and is expected to provide a replacement of more than or equal to 50% of the asphalt. Compared to hot-mix operations using virgin materials, the asphalt sand product disclosed in this disclosure can be fully recycled, effectively reducing the input of new asphalt and reducing carbon emissions caused by asphalt material manufacturing and transportation. Therefore, it not only increases the resource utilization rate of asphalt scrap but also has comprehensive benefits in terms of asphalt saving and carbon reduction.

[0152] In summary, this disclosure provides an improved method for treating asphalt stripping material, enabling the separation of asphalt in a low-energy and highly efficient manner. This disclosure uses water as a medium for asphalt stripping, eliminating the need for any organic solvents and offering environmental advantages. Furthermore, the water generated during the process can be recycled, and the recycled aggregate and asphalt sand obtained from screening are of excellent quality and have high reuse value. Therefore, it can significantly reduce the amount of aggregate and asphalt used, achieving the dual benefits of environmental sustainability and carbon reduction.

[0153] Although this disclosure has been presented above with reference to embodiments, it is not intended to limit the scope of this disclosure. Those skilled in the art to which this disclosure pertains can make various modifications and refinements without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims.

Claims

1. A method for treating asphalt removal material, characterized in that, Includes the following steps: (a) Provide bitumen stripping material, wherein the bitumen stripping material comprises a plurality of aggregates and bitumen covering the aggregates; as well as (b) The asphalt stripping material is subjected to asphalt stripping treatment, wherein the asphalt in the asphalt stripping material is at least partially separated from the plurality of aggregates by means of an asphalt stripping unit using water as a medium.

2. The method for treating asphalt removal material as described in claim 1, characterized in that, Including: Prior to step (b), the asphalt scraper is pretreated, wherein a biological agent is applied to the asphalt scraper by a pretreatment unit to form a first product.

3. The method for treating asphalt removal material as described in claim 2, characterized in that, It further includes: in step (b), using the asphalt stripping unit with water as a medium, separating at least part of the asphalt in the first product from the plurality of aggregates, and forming a second product.

4. The method for treating asphalt removal material as described in claim 3, characterized in that, Including: (c) The second product is subjected to a vibratory screening process by a water circulation screening unit to separate a third product and a fourth product, wherein the third product contains a plurality of bituminous sands and the fourth product contains a plurality of recycled stones.

5. The method for treating asphalt removal material as described in claim 4, characterized in that, The water circulation screening and treatment unit includes a screening machine, a cyclone separator, a fine sand screening machine, a sedimentation tank, and a filter press dewatering machine.

6. The method for treating asphalt removal material as described in claim 5, characterized in that, The screening machine receives a first mixture after the asphalt stripping treatment. The first mixture contains the asphalt, the plurality of aggregates and water. The screening machine separates the first mixture into a mixture containing the third product and a mixture containing the fourth product. The average particle size of the mixture containing the third product is less than 3 mm, and the average particle size of the mixture containing the fourth product is greater than or equal to 3 mm.

7. The method for treating asphalt removal material as described in claim 6, characterized in that, It further includes providing the mixture containing the third product to the cyclone separator, through which the second mixture containing particles with an average particle size of less than 0.075 mm is collected to the sedimentation tank for settling to form precipitate.

8. The method for treating asphalt removal material as described in claim 7, characterized in that, It also includes introducing the sediment into a filter press dewatering machine for squeezing to remove water, and returning the supernatant in the sedimentation tank after settling to the asphalt stripping unit for reuse.

9. The method for treating asphalt removal material as described in claim 4, characterized in that, When the total weight of the multiple asphalt sands is 100 wt%, the content of the asphalt is greater than 6 wt%.

10. The method for treating asphalt removal material as described in claim 4, characterized in that, When the total weight of the multiple recycled stones is 100 wt%, the content of the bitumen is less than 1 wt%.

11. The method for treating asphalt removal material as described in claim 4, characterized in that, The plurality of recycled stones include a first group of recycled stones, the average particle size of which is greater than or equal to 10 mm, and the content of the bitumen is less than 0.2 wt% when the total weight of the first group of recycled stones is 100 wt%.

12. The method for treating asphalt removal material as described in claim 4, characterized in that, The plurality of recycled stones include a second group of recycled stones with an average particle size of 3 mm to 10 mm, and the content of the bitumen is less than 1 wt% when the total weight of the second group of recycled stones is 100 wt%.

13. The method for treating asphalt removal material as described in claim 2, characterized in that, The bacterial species in this biological agent include bacteria belonging to the genus Bacillus, bacteria belonging to the genus Priestia, or a combination thereof.

14. The method for treating asphalt removal material as described in claim 13, characterized in that, The bacteria belonging to the genus Bacillus include Bacillus velezensis, Bacillus subtilis, Bacillus toyonensis, Bacillus licheniformis, Bacillus paralicheniformis, Bacillus thuringiensis, Bacillus pumilus, or a combination thereof. The bacteria belonging to the genus Priestia include Priestia aryabhattai, Priestia megaterium, Priestia flexa, Priestia filamentosa, Priestia endophytica, or a combination thereof.

15. The method for treating asphalt removal material as described in claim 2, characterized in that, The biological agent acts on the asphalt scraper in the form of a bacterial solution, with the weight ratio of the bacterial solution to the asphalt scraper between 0.001 and 1, and the concentration (OD) of the bacterial solution is... 600 The value is between 1 and 3.

16. The method for treating asphalt removal material as described in claim 2, characterized in that, The asphalt removal material has a first asphalt viscosity before the application of the biological agent, and the first product has a second asphalt viscosity, which is less than the first asphalt viscosity.

17. The method for treating asphalt removal material as described in claim 1, characterized in that, In step (b), the asphalt stripping process is carried out in a drum reactor.

18. The method for treating asphalt removal material as described in claim 15, characterized in that, The tangential speed of the rotary drum reactor is between 0.5 m / s and 2.5 m / s.

19. The method for treating asphalt removal material as described in claim 1, characterized in that, In step (b), the reaction temperature of the asphalt stripping treatment is between 20°C and 100°C.

20. The method for treating asphalt removal material as described in claim 1, characterized in that, In step (b), the reaction time for the asphalt stripping treatment is between 20 minutes and 130 minutes.

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