Device and method for crushing solid waste polymer into soluble fine aggregate for pavement

Abstract

The invention discloses a device and method for crushing solid waste polymers into soluble fine aggregates for pavements, and the device comprises a frame, and also comprises a cryogenic pretreatment conveying mechanism which is mounted on the frame and is used for receiving the solid waste polymers and cooling the solid waste polymers to a brittle state by using a cryogenic medium in a conveying process; the multi-stage crushing mechanism comprises a first-stage crushing assembly and a second-stage crushing assembly which are sequentially arranged in the material flowing direction; the first screening mechanism is arranged below the first-stage crushing assembly and is used for carrying out intermediate screening on the primarily crushed materials; the second-stage crushing assembly is located below the first screening mechanism. The feeding end of the conveying mechanism is used for receiving discharged materials of the second-stage crushing assembly; and a second screening mechanism. In the application, the morphology and gradation of the particles can be optimized, and the problem that the pavement material is difficult to form a tight embedding and extruding structure due to the fact that the existing particles are needle-sheet-shaped is solved.

Description

Technical Field

[0001] This invention relates to the field of crushing equipment technology, and in particular to an apparatus and method for crushing solid waste polymers into soluble fine aggregates for road surfaces. Background Technology

[0002] With the continuous expansion of the chemical and automotive industries, the generation of solid waste polymers, represented by waste plastics, rubber, and synthetic fibers, has exploded. If these high-molecular-weight wastes are not properly disposed of, they not only occupy vast amounts of land resources but also cause persistent pollution to the ecological environment. In the field of resource utilization, crushing and processing these solid waste polymers rich in high-molecular-weight hydrocarbons into fine aggregates for use in asphalt pavement engineering is currently recognized as a high-value-added utilization approach. In particular, if modified aggregates with uniform particle size, regular morphology, and certain solubility (i.e., excellent compatibility with the asphalt matrix) can be prepared, it will significantly improve the high and low temperature performance and fatigue life of asphalt mixtures, which is of great significance for improving the quality of road engineering.

[0003] In existing technologies, ambient temperature mechanical crushing is commonly used in the industrial recycling and treatment of solid waste polymers. A conventional crushing production line typically consists of a coarse crusher, a medium crusher, and a fine grinding mill. Its core working principle is to apply high-intensity shearing, extrusion, and impact forces to the material using metal blades. After physical crushing by multi-stage mechanical equipment at ambient temperature, impurities are removed through magnetic separation and air separation, ultimately yielding rubber powder or plastic particles of a certain fineness, which are then incorporated as fillers into asphalt mixtures.

[0004] However, due to the extremely high elasticity and toughness of solid waste polymers (especially rubber materials), existing traditional crushing equipment has significant limitations in preparing high-performance aggregates for road surfaces. Existing equipment mostly employs single-stage or simple multi-stage cascade crushing at room temperature, primarily relying on force tearing and impact. Due to the high elasticity of the material, it tends to deform rather than fracture under stress, resulting in particles that are often flaky, needle-like, or irregularly angular with rough surfaces and numerous burrs. The resulting particles have a wide particle size distribution and poor gradation uniformity. When these poorly shaped particles are used as asphalt mixture aggregates, their flat, elongated geometry makes it difficult for them to form a dense interlocking skeleton structure in the mixture, resulting in high interparticle porosity. This not only requires more asphalt binder for encapsulation and filling, increasing construction costs, but also severely weakens the internal friction and overall mechanical strength of the mixture. Under traffic loads, this loose structure leads to insufficient compaction density of the road surface, a significant decrease in water damage resistance and durability, and makes it difficult to meet the performance requirements of modified aggregates for high-grade highways.

[0005] Therefore, developing a crushing device that can improve particle geometry and enhance its road performance is a technical problem that urgently needs to be solved by those in the field. Summary of the Invention

[0006] The purpose of this invention is to provide an apparatus and method for crushing solid waste polymers into soluble fine aggregates for road surfaces, which can optimize particle morphology and gradation, and solve the problem that existing particles are needle-like and flaky, making it difficult for road surface materials to form a dense interlocking structure.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a device for crushing solid waste polymers into soluble fine aggregates for road surfaces, comprising a frame, and further comprising: A cryogenic pretreatment conveying mechanism, which is mounted on the frame, is used to receive solid waste polymers and cool the solid waste polymers to a brittle state during the conveying process using a cryogenic medium. A multi-stage crushing mechanism includes a first-stage crushing component and a second-stage crushing component arranged sequentially along the material flow direction. The first-stage crushing component is located below the discharge end of the cryogenic pretreatment conveying mechanism and is used to perform preliminary impact crushing on the embrittled solid waste polymer. The first screening mechanism is located below the first-stage crushing component and is used for intermediate screening of the material after preliminary crushing. The second-stage crushing component is located below the first screening mechanism and is used to receive the material processed by the first screening mechanism and perform secondary fine crushing and shaping. The conveying mechanism receives the discharge from the second-stage crushing component at its feed end and is used to convey the material after secondary crushing. And a second screening mechanism, which is located at the discharge end of the conveying mechanism, is used to receive the conveyed material and perform multi-stage sorting to obtain soluble fine aggregate with continuous gradation.

[0008] Preferably, the cryogenic pretreatment conveying mechanism includes a barrel with a double-layer vacuum insulation structure. A stirring conveying shaft is rotatably installed inside the barrel. Several liquid nitrogen atomizing nozzles are arranged in an axial array on the inner wall of the barrel. The liquid nitrogen atomizing nozzles cover the working range of the stirring conveying shaft. The liquid nitrogen atomizing nozzles are also connected to an external liquid nitrogen storage tank through an insulated pipeline, and a cryogenic solenoid valve for adjusting the liquid nitrogen flow rate is provided on the insulated pipeline.

[0009] Preferably, the first-stage crushing assembly includes a primary crushing chamber. Inside the primary crushing chamber, two parallel first crushing shafts are rotatably mounted. The two first crushing shafts are driven to rotate synchronously in opposite directions by a first driving mechanism located outside the primary crushing chamber. Multiple first crushing cutters are arranged around the outer circumference of each first crushing shaft, and the first crushing cutters on the two first crushing shafts interlock and mesh with each other on the rotation trajectory. One side of the first crushing cutter along the rotation direction is provided with an arc-shaped cutting edge, and the root to the top of the first crushing cutter has a spiral twist structure.

[0010] Preferably, the second-stage crushing assembly includes a shaping housing with openings at both the top and bottom. Two shaping and crushing shafts are rotatably mounted parallel inside the shaping housing. The surfaces of the shaping and crushing shafts are densely distributed with a number of shaping blades. The two shaping and crushing shafts are driven by an independently set second drive mechanism. A fixed blade grid plate is fixedly installed on the inner side wall of the shaping housing. The fixed blade grid plate has a number of comb-shaped shearing slots corresponding to the positions of the shaping blades. When the shaping blades rotate with the shafts, they can penetrate and pass through the comb-shaped shearing slots of the fixed blade grid plate. By utilizing the bidirectional shearing action between the shaping blades and the fixed blade grid plate, coarse particles after being screened by the first screening mechanism are forcibly shaped and sized.

[0011] Preferably, the first screening mechanism is installed at the top feed end of the shaping machine housing. The first screening mechanism includes a first mounting bracket, which is elastically connected to a first screening box via several first damping springs. A first vibration motor is installed on the outside of the first screening box, and a first-level screen for coarse and fine separation is provided inside. The undersize outlet of the first screening box is vertically connected to the inside of the shaping machine housing, so that the material screened by the first screening mechanism falls directly into the second-stage crushing component for shaping.

[0012] Preferably, the conveying mechanism includes a conveyor cylinder, the feed end of which is connected to the discharge port of the second-stage crushing component through a transition hopper, the discharge end of which extends above the second screening mechanism, and a spiral conveying shaft is rotatably installed inside the conveyor cylinder to lift and convey the material from the feed end to the discharge end.

[0013] Preferably, the outer wall of the conveyor cylinder is covered with an electric heating jacket to maintain the environment inside the conveyor cylinder at a preset activation temperature. Several ultraviolet photolysis components are installed axially at intervals on the top inner wall of the conveyor cylinder. The ultraviolet photolysis components are located above the spiral conveyor shaft. Each ultraviolet photolysis component includes an ultraviolet lamp and a dustproof quartz glass tube covering the ultraviolet lamp. The ultraviolet photolysis components are used in conjunction with the high-temperature environment generated by the electric heating jacket to perform surface-oriented pyrolysis on the solid waste polymer particles that move forward with the spiral conveyor shaft inside the conveyor cylinder, so as to achieve activation modification of the particle surface.

[0014] Preferably, the second screening mechanism includes a second mounting bracket set on the ground. The second mounting bracket is elastically connected to an inclined second screening box via several second damping springs. A second vibration motor is fixedly installed on the outside of the second screening box. At least two layers of second-level screens with different apertures are arranged vertically inside the box to classify the received material into particles of different particle size ranges. Each layer of screen and the bottom screen material on the second screening box has an independent discharge port for discharging modified fine aggregate with continuous gradation.

[0015] Another object of the present invention is to provide a method for preparing polymer-soluble fine aggregates for road surfaces, comprising the following steps: S1. Cryogenic Embrittlement: Start the cryogenic pretreatment conveying mechanism installed on the frame, put the solid waste polymer raw material into the feed end of the cryogenic pretreatment conveying mechanism, and use the cryogenic medium to cool the solid waste polymer to below the glass transition temperature during the conveying process, so that it becomes brittle. S2, Primary Crushing and Intermediate Screening: The brittle solid waste polymer is introduced into the first-stage crushing component for preliminary impact crushing. The crushed material is then sent to the first screening mechanism located below for intermediate screening. The material that meets the particle size requirements is directly introduced into the second-stage crushing component. S3, Secondary Shaping: The received material is further refined and shaped using the secondary crushing component. Through internal shearing and sizing, irregular edges on the particle surface are eliminated to obtain aggregate particles with regular geometric shape. S4. Photothermal Activation Conveying: The shaped aggregate particles are fed into the conveying mechanism, which lifts and conveys the material. During the conveying process, nitrogen is introduced into the internal environment of the conveying mechanism to create an inert atmosphere, and the internal environment of the conveying mechanism is heated to 200℃-260℃. At the same time, ultraviolet light irradiation is used to perform surface-directed pyrolysis and activation modification on the material moving in the conveying mechanism. S5. Finished Product Grading: The modified aggregate particles are discharged from the discharge end of the conveying mechanism to the second screening mechanism. The second screening mechanism performs multi-stage sorting of the material and discharges particles of different particle size ranges to obtain soluble fine aggregate for road surface with continuous gradation.

[0016] Compared with the prior art, the advantages of this invention are as follows: This device introduces a cryogenic pretreatment conveying mechanism as the first process, and uses a cryogenic medium to dynamically freeze the solid waste polymer during the conveying process, so that it is rapidly cooled to below the glass transition temperature, thereby changing from a high elastic and tough state at room temperature to a high brittle state. This phase transition changes the subsequent crushing mechanism from high-energy mechanical shearing and tearing to low-energy impact crushing. While significantly reducing crushing resistance and equipment wear, it completely avoids material scorching and blade sticking caused by frictional heat generation.

[0017] Based on this, the device employs a process layout of coarse crushing, intermediate screening, and fine crushing and shaping. The first-stage crushing unit utilizes impact force for efficient coarse crushing of embrittled large materials. Combined with the intermediate diversion effect of the first screening mechanism, this not only achieves precise material classification but also ensures the efficiency of subsequent processing. The second-stage crushing unit focuses on secondary refinement and mechanical shaping of the screened material, effectively eliminating needle-like and flaky particles and significantly improving the geometry and cubicity of the aggregate. Finally, through the coordinated operation of the end conveying mechanism and the second screening mechanism, multi-stage fine sorting of the finished product is achieved, resulting in high-quality fine aggregate with continuous gradation that meets the stringent requirements of road engineering. The entire device's process flow is tightly integrated, ensuring the physical properties of the aggregate while significantly improving overall production efficiency and energy utilization. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of a solid waste tire shredding device according to this application. Figure 1 ; Figure 2 This is a schematic diagram of the overall structure of a solid waste tire shredding device according to this application. Figure 2 ; Figure 3 This is a schematic diagram of the cryogenic pretreatment conveying mechanism of a solid waste tire crushing device according to this application; Figure 4This is a schematic diagram of the first-stage crushing mechanism of a solid waste tire crushing device according to this application; Figure 5 This is a schematic diagram of the first screening mechanism of a solid waste tire crushing device according to this application; Figure 6 This is a schematic diagram of the structure of the second-stage crushing component of a solid waste tire crushing device according to this application; Figure 7 This is a schematic diagram of the conveying mechanism of a solid waste tire crushing device according to this application; Figure 8 This is a schematic diagram of the second screening mechanism of a solid waste tire crushing device in this application; 1. Framework; 2. First-stage crushing assembly; 21. First-stage crushing chamber; 22. First crushing shaft; 23. First drive mechanism; 24. First crushing cutter head; 3. Cryogenic pretreatment conveying mechanism; 31. Barrel; 32. Stirring and conveying shaft; 33. Liquid nitrogen atomizing nozzle; 34. Insulated pipeline; 35. Cryogenic solenoid valve; 36. Liquid nitrogen storage tank; 4. First screening mechanism; 41. First mounting bracket; 42. First shock-absorbing spring; 43. First screening box; 44. First vibrating motor; 45. First-stage screen; 5. Second-stage crushing assembly; 51. Shaping housing; 52. Shaping and crushing shaft; 53. Second drive mechanism; 54. Knife grille; 6. Conveying mechanism; 61. Conveyor cylinder; 62. Screw conveyor shaft; 63. Electric heating jacket; 64. Ultraviolet lamp tube; 65. Dustproof quartz glass tube; 7. Second screening mechanism; 71. Second mounting bracket; 72. Second shock-absorbing spring; 73. Second screening box; 74. Second vibrating motor; 75. Second-level screen. Detailed Implementation

[0020] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the content of the embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] Example 1: As Figures 1 to 8 As shown, an apparatus for crushing solid waste polymers into soluble fine aggregates for road surfaces includes a frame 1 and further includes: The cryogenic pretreatment conveying mechanism 3, which is installed on the frame 1, is used to receive solid waste polymer and cool the solid waste polymer to a brittle state during the conveying process using a cryogenic medium. The multi-stage crushing mechanism includes a first-stage crushing component 2 and a second-stage crushing component 5 arranged sequentially along the material flow direction. The first-stage crushing component 2 is located below the discharge end of the cryogenic pretreatment conveying mechanism 3 and is used to perform preliminary impact crushing on the embrittled solid waste polymer. The first screening mechanism 4 is located below the first-stage crushing component 2 and is used for intermediate screening of the material after preliminary crushing. The second-stage crushing component 5 is located below the first screening mechanism 4 and is used to receive the material processed by the first screening mechanism 4 and perform secondary fine crushing and shaping. The conveying mechanism 6 receives the discharge from the second-stage crushing component 5 at its feed end and is used to convey the material after secondary crushing. And a second screening mechanism 7, which is located at the discharge end of the conveying mechanism 6, is used to receive the conveyed material and perform multi-stage sorting to obtain soluble fine aggregate with continuous gradation.

[0022] In this embodiment, the cryogenic pretreatment conveying mechanism 3 includes a barrel 31 with a double-layer vacuum insulation structure. A stirring conveying shaft 32 is rotatably installed inside the barrel 31. Several liquid nitrogen atomizing nozzles 33 are arranged in an axial array on the inner wall of the barrel 31. The liquid nitrogen atomizing nozzles 33 cover the working range of the stirring conveying shaft 32. The liquid nitrogen atomizing nozzles 33 are also connected to an external liquid nitrogen storage tank 36 through an insulated pipeline 34. A cryogenic solenoid valve 35 for adjusting the liquid nitrogen flow rate is provided on the insulated pipeline 34.

[0023] In the aforementioned structure, the double-layer vacuum-insulated barrel 31 constructs a highly efficient cold energy shield, significantly blocking heat exchange between the device's interior and the external environment. This significantly reduces liquid nitrogen cold energy loss while effectively preventing frost or cracking of the barrel 31's outer wall due to overcooling, thus improving the equipment's safety and energy efficiency. The axially arrayed liquid nitrogen atomizing nozzles 33 and the internally rotating stirring and conveying shaft 32 form a dynamically coupled, highly efficient heat exchange field. The stirring and conveying shaft 32 forces the material to tumble up and down while propelling it, and combined with the wide-angle coverage of atomized liquid nitrogen, ensures that both the surface and depth of the moving solid waste polymer particles are fully in contact with the cryogenic medium, completely overcoming the technical challenges of low thermal conductivity in rubber materials and the difficulty of freezing through simple accumulation. Furthermore, the liquid supply circuit constructed through the insulated pipeline 34 and the cryogenic solenoid valve 35 allows the system to flexibly adjust the liquid nitrogen flow rate according to the material throughput or real-time temperature feedback, achieving on-demand supply and precise control of the cryogenic embrittlement process, maximizing cost savings while ensuring the embrittlement effect.

[0024] In this embodiment, the first-stage crushing component 2 includes a first-stage crushing box 21. Two parallel first crushing shafts 22 are rotatably mounted inside the first-stage crushing box 21. The two first crushing shafts 22 are driven to rotate synchronously in opposite directions by a first driving mechanism 23 located outside the first-stage crushing box 21. Multiple first crushing cutters 24 are arranged around the outer circumference of each first crushing shaft 22. The first crushing cutters 24 on the two first crushing shafts 22 interlock and mesh with each other on the rotation trajectory. The first crushing cutter 24 has an arc-shaped cutting edge on one side along the rotation direction, and the root to the top of the first crushing cutter 24 has a spiral twist structure.

[0025] The primary crushing component 2 employs a dual-axis synchronous counter-rotation drive, creating a powerful material biting zone between the two parallel crushing shafts. This efficiently captures and entrains large solid waste polymers that have undergone cryogenic embrittlement, effectively preventing material rebound or splashing during crushing. Furthermore, due to its unique cutter geometry, the first crushing cutters 24 on the two shafts form a tight, interlocking shearing field along their rotational trajectory. Combined with the arc-shaped cutting edges along the rotational direction and the spiral torsion structure from root to top, this transforms traditional instantaneous planar impact crushing into continuous, progressive point-contact shearing crushing. This spiral torsion design not only significantly reduces instantaneous resistance and vibration when cutting brittle materials and smooths out torque peaks, but also utilizes the spiral guiding effect to promote rapid material detachment from the blades, preventing material buildup and blockage between the shafts. This ensures that large materials are rapidly broken down into smaller fragments while significantly improving crushing efficiency and extending the service life of core components.

[0026] In this embodiment, the second-stage crushing component 5 includes a shaping housing 51 with openings at both the top and bottom. Two shaping and crushing shafts 52 are rotatably mounted inside the shaping housing 51. The surfaces of the shaping and crushing shafts 52 are densely distributed with a number of shaping blades. The two shaping and crushing shafts 52 are driven by an independently set second drive mechanism 53. A fixed blade grid plate 54 is fixedly installed on the inner side wall of the shaping housing 51. The fixed blade grid plate 54 has a number of comb-shaped shearing slots corresponding to the positions of the shaping blades. When the shaping blades rotate with the shaft, they can penetrate and pass through the comb-shaped shearing slots of the fixed blade grid plate 54. By utilizing the bidirectional shearing action between the shaping blades and the fixed blade grid plate 54, the coarse particles after being screened by the first screening mechanism 4 are forcibly shaped and sized.

[0027] The power system of the second-stage crushing component 5 adopts an independently configured second drive mechanism 53. The second drive mechanism 53 preferably adopts a high-torque reduction motor set, which provides constant torque output to the two shaping crushing shafts 52 through a rigid coupling, chain drive assembly or gear drive assembly, respectively, to ensure stable cutting power when processing high-hardness or high-toughness aggregates.

[0028] At the crushing execution end, this component constructs a constrained shearing system based on the precise interference of moving and stationary cutters. Among them, the fixed cutter grid plate 54 serves as a static constraint component, and the comb-shaped shearing slots opened on it form a shearing channel with specific geometric dimensions, while the shaping cutter teeth on the shaping crushing shaft 52 serve as dynamic execution components, and their rotation trajectory is designed to accurately probe into and pass through the aforementioned shearing channel.

[0029] During operation, the shaping blade teeth and the edge of the fixed blade grid plate 54 form a closed shear pair. When material enters this area, due to the geometric constraint of the shear gap, irregular elongated or sheet-like particles cannot pass directly but are forcibly retained within the shear gap. As the shaping blade teeth rotate and cut in, the material is subjected to high-intensity bidirectional shear stress and compressive stress between the front cutting face of the moving blade and the side wall of the fixed blade, resulting in brittle fracture or plastic cutting. This forced mechanical action not only peels away irregular protrusions on the particle surface, achieving the shaping of the particle's microstructure, but also uses the gap width as a physical screening threshold to ensure that only regular particles with a particle size smaller than the set value can pass through, thus achieving the dual process objectives of aggregate particle size control and morphology optimization.

[0030] In this embodiment, the first screening mechanism 4 is installed at the top feed end of the shaping machine housing 51. The first screening mechanism 4 includes a first mounting bracket 41. The first mounting bracket 41 is elastically connected to a first screening box 43 through several first damping springs 42. A first vibration motor 44 is installed on the outside of the first screening box 43, and a first-level screen 45 for coarse and fine separation is provided inside. The undersize outlet of the first screening box 43 is vertically connected to the inside of the shaping machine housing 51, so that the material screened by the first screening mechanism 4 falls directly into the second-stage crushing component 5 for shaping.

[0031] The first screening mechanism 4 adopts a compact, vertically integrated layout, directly coupling the intermediate screening process to the feed end of the second-stage crushing process. Its advantage lies in the elastic suspension system constructed through mounting brackets and shock-absorbing springs. On one hand, this provides the necessary degrees of freedom for the screening box under the high-frequency excitation of the vibrating motor, ensuring sufficient throwing and screening motion of the material on the screen surface, preventing mesh clogging and improving sorting efficiency. On the other hand, this elastic connection forms an effective mechanical vibration isolation barrier, blocking the transmission of high-frequency vibrations generated during screening to the static shaping housing 51 below, thereby protecting the operational stability and assembly accuracy of the precision shaping cutter shaft. Furthermore, the vertical direct connection between the undersize outlet and the interior of the shaping housing 51 fully utilizes the gravitational potential energy of the material to achieve automatic inter-stage conveying, eliminating intermediate transfer links and ensuring that the sorted material can fall directly into the shearing operation zone of the shaping and crushing chamber in a uniform flow, achieving seamless process integration and efficient feeding.

[0032] In this embodiment, the conveying mechanism 6 includes a conveyor cylinder 61. The feed end of the conveyor cylinder 61 is connected to the discharge port of the second-stage crushing component 5 through a transition hopper. The discharge end of the conveyor cylinder 61 extends above the second screening mechanism 7. A screw conveyor shaft 62 is rotatably installed inside the conveyor cylinder 61 along the axial direction. The screw conveyor shaft 62 is used to lift and convey the material from the feed end to the discharge end.

[0033] By setting up a transition hopper, a geometric fit and buffer transition are achieved between the rectangular discharge port of the crushing component and the circular feed port of the conveyor cylinder 61, effectively preventing material splashing and accumulation at the transfer junction. During operation, the internal spiral conveyor shaft 62 generates continuous axial thrust under the driving force, lifting the material particles entering the cylinder upwards against gravity, realizing directional conveying from the discharge end of the second-stage crushing component 5 to above the second screening mechanism 7. This design not only uses mechanical lifting to compensate for the difference in gravitational potential energy between the preceding and following processes, ensuring that the material can uniformly enter the subsequent screening stage by gravity flow, but its closed tubular structure also effectively curbs dust overflow of dried fine aggregate during high-speed conveying, significantly improving the environmental performance of the system.

[0034] In this embodiment, the outer wall of the conveyor cylinder 61 is covered with an electric heating jacket 63 to maintain the environment inside the conveyor cylinder 61 at a preset activation temperature. Several ultraviolet photolysis components are installed axially at intervals on the top inner wall of the conveyor cylinder 61. The ultraviolet photolysis components are located above the screw conveyor shaft 62. The ultraviolet photolysis components include an ultraviolet lamp tube 64 and a dustproof quartz glass tube 65 covering the ultraviolet lamp tube 64. The ultraviolet photolysis components are used in conjunction with the high temperature environment generated by the electric heating jacket 63 to perform surface-oriented pyrolysis on the solid waste polymer particles that move forward with the screw conveyor shaft 62 inside the conveyor cylinder 61, so as to achieve activation modification of the particle surface.

[0035] In the above structure, the electric heating jacket 63, which covers the outer wall, serves as the heat supply unit. The heating temperature of the electric heating jacket 63 is 220-260℃. It creates a stable and controllable high-temperature activation environment inside the barrel through heat conduction, effectively reducing the activation energy required for the molecular chain breakage of solid waste polymers and keeping the particle surface in a pre-activated state of thermal softening. The ultraviolet photolysis component located at the top of the barrel serves as the photo-excitation unit. Utilizing the physical isolation and high light transmittance of the dustproof quartz glass tube 65, it isolates dust pollution and mechanical wear while ensuring that the high-energy ultraviolet beam can penetrate without damage and act on the material surface. At a temperature of 220-260℃, the ultraviolet light causes the breaking and depolymerization of sulfur bonds between the rubber hydrocarbon backbone (chain breakage of C-C bonds and C=C bonds in the rubber hydrocarbon backbone), disrupting the three-dimensional cross-linked network structure of the waste tire rubber powder particles. This increases the surface area of ​​the particles and significantly improves the compatibility with asphalt. The system also utilizes the dynamic tumbling effect during the screw conveying process. When the drive motor drives the screw conveyor shaft 62 to rotate, the particles move forward with the screw conveyor shaft 62, and their light-receiving surfaces are constantly and randomly changed. This ensures that the particle surface at high temperature can receive ultraviolet radiation in all directions and uniformly. This thermal field-assisted directional photolysis mechanism efficiently breaks the chemical bonds on the polymer surface at the microscopic level, successfully transforming the originally inert physical surface into a modified interface rich in active functional groups, and significantly improving the chemical compatibility between aggregate and asphalt matrix.

[0036] In a preferred embodiment of the present invention, a nitrogen injection port is provided on the conveyor cylinder 61 to create an inert reaction environment at high temperatures. The nitrogen injection port is connected to an external nitrogen source (such as the vaporization end of a liquid nitrogen storage tank or a nitrogen generator) via a gas pipeline, and a gas flow regulating valve is installed on the pipeline. During the operation of the device, especially when the electric heating jacket 63 and the ultraviolet photolysis component are turned on, high-purity nitrogen is continuously introduced into the conveyor cylinder 61 through the nitrogen injection port, and the positive pressure gas displaces the air inside the cylinder, thereby forming a low-oxygen or oxygen-free inert protective atmosphere in the sealed space of the conveyor cylinder 61.

[0037] In this embodiment, the second screening mechanism 7 includes a second mounting bracket 71 disposed on the ground. The second mounting bracket 71 is elastically connected to an inclined second screening box 73 via several second damping springs 72. A second vibration motor 74 is fixedly installed on the outside of the second screening box 73. At least two layers of second-level screens 75 with different apertures are arranged vertically inside the box to classify the received material into particles of different particle size ranges. The second screening box 73 has independent discharge ports corresponding to each level of screen and the bottom screen material to discharge soluble fine aggregates with continuous gradation.

[0038] The second screening mechanism 7, as the terminal grading unit of the entire system, mainly undertakes the key task of precise particle size control and gradation reorganization of the photothermally modified aggregate. This component adopts an independent ground-mounted architecture, constructing a stable elastic suspension system through mounting brackets and shock-absorbing springs. This design ensures that the screening box can respond to the high-frequency excitation force of the vibrating motor to generate large-amplitude screening movements, while effectively blocking the transmission of dynamic loads to the foundation, achieving good vibration reduction and noise insulation effects.

[0039] The inclined screening box, combined with a multi-layered screen structure with decreasing apertures, utilizes the combined effect of gravity and vibration to force the material into continuous throwing and sliding motions on the screen surface. This complex motion trajectory allows the mixed aggregate to quickly loosen and stratify, with fine particles rapidly passing through the upper large-aperture screen into the lower layer, while coarse particles slide along the screen surface towards the discharge end. By setting at least two second-stage screens 75 with different mesh sizes, the device can precisely separate the aggregate into multiple particle size ranges in one pass, each discharged through its own independent outlet. This ensures that the output has continuous gradation characteristics that meet the requirements of road engineering design, completely eliminating mixing and providing high-quality standardized raw materials for the subsequent preparation of asphalt mixtures.

[0040] Example 2: A method for preparing polymer-soluble fine aggregates for road surface using the apparatus in Example 1, comprising the following steps: S1. Cryogenic embrittlement: Start the cryogenic pretreatment conveying mechanism 3 installed on the frame 1, put the solid waste polymer raw material into the feed end of the cryogenic pretreatment conveying mechanism 3, and use the cryogenic medium to cool the solid waste polymer to below the glass transition temperature during the conveying process, so that it becomes brittle. S2, Primary crushing and intermediate screening: The brittle solid waste polymer is introduced into the first-stage crushing component 2 for preliminary impact crushing. Then, the crushed material is sent to the first screening mechanism 4 located below for intermediate screening. The material that meets the particle size requirements is directly introduced into the second-stage crushing component 5. S3, Secondary Shaping: The received material is further refined and shaped using the second-stage crushing component 5. Through internal shearing and sizing, irregular edges on the particle surface are eliminated to obtain aggregate particles with regular geometric shapes. S4. Photothermal activation conveying: The shaped aggregate particles are fed into the conveying mechanism 6, and the conveying mechanism 6 is used to lift and convey the material. During the conveying process, nitrogen gas is introduced into the internal environment of the conveying mechanism 6 to create an inert atmosphere, and the internal environment of the conveying mechanism 6 is heated to 200℃-260℃. At the same time, ultraviolet light irradiation is used to perform surface-oriented pyrolysis and activation modification on the material moving in the conveying mechanism 6. S5. Finished product grading: The modified aggregate particles are discharged from the discharge end of the conveying mechanism 6 to the second screening mechanism 7. The second screening mechanism 7 is used to perform multi-stage sorting of the material and discharge particles of different particle size ranges to obtain soluble fine aggregate for road surface with continuous gradation.

[0041] The preparation method provided by this invention significantly improves the efficiency and quality of solid waste polymer recycling by organically combining cryogenic embrittlement, graded shaping, and environmentally controlled photothermal modification processes. Firstly, in the cryogenic embrittlement step, a cryogenic medium rapidly cools the highly elastic solid waste polymer to below its glass transition temperature, transforming it into a brittle state. This phase transition completely changes the material's physical properties, causing the subsequent crushing mechanism to change from high-energy mechanical shearing and tearing to low-energy impact brittle fracture. This not only significantly reduces the equipment's operating load but also effectively avoids material scorching and equipment sticking caused by frictional heat generation. Furthermore, the brittle fracture produces cleaner and sharper particle surfaces, which is beneficial for subsequent processing.

[0042] Based on this, the method adopts a stepped processing approach that combines coarse crushing, intermediate screening and fine shaping. The intermediate screening stage separates qualified fine materials in a timely manner, avoids over-crushing and increases the system throughput. The secondary shaping step uses shearing and sizing to forcibly eliminate the needle-like and flaky edges on the particle surface, ensuring that the aggregate has a near-cubic regular shape from a physical and geometric perspective, thereby significantly improving its bulk density and interlocking force in road applications.

[0043] This method constructs a unique photothermal coupling reaction system under nitrogen protection during the transportation and modification stages. By heating the environment to 200℃-260℃ to pre-soften the polymer surface and reduce the activation energy, and then using directional ultraviolet light to break the surface vulcanization crosslinks, active functional groups can be induced. The introduction of a nitrogen inert atmosphere completely eliminates the safety hazards of spontaneous combustion or explosion of rubber dust under high-temperature conditions, and effectively shields against oxygen interference, preventing deep oxidation or carbonization of molecular chains during bond breaking. This successfully constructs an internally hard and externally active aggregate structure with a high-strength core and excellent asphalt compatibility. Finally, a multi-stage sorting mechanism ensures that the product has a continuous gradation that meets the stringent requirements of road engineering, providing high-quality raw materials for the preparation of high-performance asphalt mixtures.

[0044] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An apparatus for crushing solid waste polymers into soluble fine aggregates for road surfaces, comprising a frame (1), characterized in that, Also includes: A cryogenic pretreatment conveying mechanism (3), which is installed on the frame (1), is used to receive solid waste polymer and cool the solid waste polymer to a brittle state during the conveying process using a cryogenic medium; The multi-stage crushing mechanism includes a first-stage crushing component (2) and a second-stage crushing component (5) arranged sequentially along the material flow direction. The first-stage crushing component (2) is located below the discharge end of the cryogenic pretreatment conveying mechanism (3) and is used to perform preliminary impact crushing on the embrittled solid waste polymer. The first screening mechanism (4) is located below the first-stage crushing component (2) and is used to perform intermediate screening on the material after preliminary crushing. The second-stage crushing component (5) is located below the first screening mechanism (4) and is used to receive the material processed by the first screening mechanism (4) and perform secondary fine crushing and shaping. The conveying mechanism (6) receives the discharge of the second-stage crushing component (5) at its feed end and is used to convey the material after secondary crushing. And a second screening mechanism (7), which is located at the discharge end of the conveying mechanism (6), is used to receive the conveyed material and perform multi-stage sorting to obtain soluble fine aggregate with continuous gradation.

2. The apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use according to claim 1, characterized in that, The cryogenic pretreatment conveying mechanism (3) includes a barrel (31) with a double-layer vacuum insulation structure. A stirring conveying shaft (32) is rotatably installed inside the barrel (31). Several liquid nitrogen atomizing nozzles (33) are arranged in an axial array on the inner wall of the barrel (31). The liquid nitrogen atomizing nozzles (33) cover the working range of the stirring conveying shaft (32). The liquid nitrogen atomizing nozzles (33) are also connected to an external liquid nitrogen storage tank (36) through an insulated pipeline (34). A cryogenic solenoid valve (35) for adjusting the liquid nitrogen flow rate is provided on the insulated pipeline (34).

3. The apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use according to claim 1, characterized in that, The first-stage crushing assembly (2) includes a first-stage crushing box (21). Two parallel first crushing shafts (22) are rotatably mounted inside the first-stage crushing box (21). The two first crushing shafts (22) are driven to rotate synchronously in opposite directions by a first driving mechanism (23) located outside the first-stage crushing box (21). Multiple first crushing cutters (24) are arranged around the outer circumference of each first crushing shaft (22). The first crushing cutters (24) on the two first crushing shafts (22) interlock and mesh with each other on the rotation trajectory. The first crushing cutter (24) has an arc-shaped cutting edge on one side along the rotation direction. The root to the top of the first crushing cutter (24) has a spiral twist structure.

4. The apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use according to claim 1, characterized in that, The second-stage crushing assembly (5) includes a shaping housing (51) with openings at both the top and bottom. Two shaping and crushing shafts (52) are installed in parallel inside the shaping housing (51). Several shaping teeth are densely distributed on the surface of the shaping and crushing shafts (52). The two shaping and crushing shafts (52) are driven by an independently set second drive mechanism (53). A fixed blade grid plate (54) is fixedly installed on the inner side wall of the shaping housing (51). Several comb-shaped shearing slots corresponding to the positions of the shaping teeth are opened on the fixed blade grid plate (54). When the shaping teeth rotate with the shaft, they can probe into and pass through the comb-shaped shearing slots of the fixed blade grid plate (54). By utilizing the bidirectional shearing action between the shaping teeth and the fixed blade grid plate (54), the coarse particles after being screened by the first screening mechanism (4) are forcibly shaped and sized.

5. The apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use according to claim 4, characterized in that, The first screening mechanism (4) is installed at the top feed end of the shaping machine housing (51). The first screening mechanism (4) includes a first mounting bracket (41). The first mounting bracket (41) is elastically connected to a first screening box (43) by several first damping springs (42). A first vibration motor (44) is installed on the outside of the first screening box (43). A first-level screen (45) for coarse and fine separation is provided inside. The undersize outlet of the first screening box (43) is vertically connected to the inside of the shaping machine housing (51), so that the material screened by the first screening mechanism (4) falls directly into the second-stage crushing component (5) for shaping.

6. The apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use according to claim 1, characterized in that, The conveying mechanism (6) includes a conveyor cylinder (61). The feed end of the conveyor cylinder (61) is connected to the discharge port of the second-stage crushing component (5) through a transition hopper. The discharge end of the conveyor cylinder (61) extends above the second screening mechanism (7). A spiral conveying shaft (62) is rotatably installed inside the conveyor cylinder (61) along the axial direction. The spiral conveying shaft (62) is used to lift and convey the material from the feed end to the discharge end.

7. The apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use according to claim 6, characterized in that, The outer wall of the conveyor cylinder (61) is covered with an electric heating jacket (63) to maintain the environment inside the conveyor cylinder (61) at a preset activation temperature. Several ultraviolet photolysis components are installed axially at intervals on the top inner wall of the conveyor cylinder (61). The ultraviolet photolysis components are located above the spiral conveyor shaft (62). The ultraviolet photolysis components include an ultraviolet lamp tube (64) and a dustproof quartz glass tube (65) covering the outside of the ultraviolet lamp tube (64). The ultraviolet photolysis components are used in conjunction with the high temperature environment generated by the electric heating jacket (63) to perform surface-oriented pyrolysis on the solid waste polymer particles that move forward with the spiral conveyor shaft (62) inside the conveyor cylinder (61) to achieve activation modification of the particle surface.

8. The apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use according to claim 1, characterized in that, The second screening mechanism (7) includes a second mounting bracket (71) set on the ground. The second mounting bracket (71) is elastically connected to an inclined second screening box (73) through several second damping springs (72). A second vibration motor (74) is fixedly installed on the outside of the second screening box (73). At least two layers of second-level screens (75) with different apertures are arranged vertically inside the box for classifying the received material into particles of different particle size ranges. The second screening box (73) has independent discharge ports for each level of screen and the bottom screen material, for discharging soluble fine aggregates with continuous gradation.

9. A method for crushing solid waste polymers into soluble fine aggregates for road surface use, based on the apparatus for crushing solid waste polymers into soluble fine aggregates for road surface use as described in any one of claims 1-8, characterized in that, S1, cryogenic embrittlement: Start the cryogenic pretreatment conveying mechanism (3) installed on the frame (1), put the solid waste polymer raw material into the feed end of the cryogenic pretreatment conveying mechanism (3), and use the cryogenic medium to cool the solid waste polymer to below the glass transition temperature during the conveying process, so that it becomes brittle. S2, Primary crushing and intermediate screening: The brittle solid waste polymer is introduced into the first-stage crushing component (2) for preliminary impact crushing, and then the crushed material is sent to the first screening mechanism (4) located below for intermediate screening. The material that meets the particle size requirements is directly introduced into the second-stage crushing component (5). S3, Secondary Shaping: The received material is further refined and shaped by the secondary crushing component (5). Through internal shearing and sizing, the irregular edges on the particle surface are eliminated, and aggregate particles with regular geometric shape are obtained. S4, Photothermal Activation Conveying: The shaped aggregate particles are fed into the conveying mechanism (6), and the material is lifted and conveyed by the conveying mechanism (6); during the conveying process, nitrogen is introduced into the internal environment of the conveying mechanism (6) to create an inert atmosphere, and the internal environment of the conveying mechanism (6) is heated to a preset temperature. At the same time, ultraviolet light irradiation is used to perform surface-oriented pyrolysis and activation modification on the material moving in the conveying mechanism (6); S5. Finished product grading: The modified aggregate particles are discharged from the discharge end of the conveying mechanism (6) to the second screening mechanism (7). The second screening mechanism (7) is used to perform multi-stage sorting of the material and discharge particles of different particle size ranges, thereby obtaining soluble fine aggregate for road surface with continuous gradation.

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