A waste concrete recycling device and method

Abstract

The application relates to the field of waste concrete recycling, in particular to a waste concrete recycling device and method, which comprises, in sequence along a material processing direction, a pretreatment unit, a multistage crushing unit, a screening unit, a return material mechanism, an aggregate purification unit, a dust removal unit and a cleaning unit; the pretreatment unit comprises a vibrating feeder, a microwave heating cavity and a material shunting mechanism; the multistage crushing unit comprises a primary crusher, a secondary crusher and a shaping crusher; the screening unit comprises a screening mechanism in communication with a discharge end of the shaping crusher; the return material mechanism is connected with the screening mechanism at an inlet and communicated with the secondary crusher at an outlet; the aggregate purification unit comprises a magnetic separation mechanism; the dust removal unit is communicated with each dust generation point of the device; and the cleaning unit comprises a steam generating device communicated with each crushing mechanism. The application has the effects of efficient crushing, effective dust suppression and accurate sorting when recycling waste concrete.

Description

Technical Field

[0001] This application relates to the field of waste concrete recycling, and in particular to a waste concrete recycling and reuse device and method. Background Technology

[0002] The construction, renovation, and demolition of various buildings generate a large amount of waste concrete, cement blocks, and recycled asphalt concrete. To achieve resource recycling, these waste materials need to be crushed and screened to obtain aggregates that can be used for recycled building materials.

[0003] The common method for handling waste concrete blocks is direct mechanical crushing. This crushing process generates a large amount of micron-sized dust, resulting in the invisible waste of recycled materials, and the dispersed dust severely pollutes the working environment and the surrounding atmosphere. Furthermore, while water mist spraying systems introduced to suppress dust can partially inhibit it, the dust can combine with fine particles to form a viscous, muddy mixture. This mud has extremely strong adhesion, easily adhering to the crushing chamber walls, screens, and conveying equipment surfaces. This not only makes cleaning difficult but also increases equipment operating resistance, significantly reduces screening efficiency, and can even lead to frequent downtime for maintenance, severely impacting production continuity and economic efficiency.

[0004] Specifically, in the treatment of recycled asphalt concrete, due to the inherent viscosity of asphalt, the recycled material contains a large amount of agglomerated material formed by residual asphalt adhesion. While existing screening and crushing equipment can handle obviously lumpy or oversized materials, it struggles to effectively address these agglomerated materials with varying internal cohesion and external looseness. Existing technologies mostly employ a single impact or compression crushing principle, resulting in concentrated force and a high agglomeration rate even in the crushed product. For large-volume, irregular reinforced concrete waste generated from building demolition, existing treatment technologies are mostly single-function, only capable of preliminary crushing of concrete, and severely lacking dedicated modules for efficient and clean separation of concrete from embedded reinforcing steel. This leads to the ineffective recycling of reinforcing steel resources, resulting in their mixing with concrete fragments in landfills and causing significant resource waste. Furthermore, most existing technologies employ dry processing methods, generating massive amounts of dust during the process, causing serious secondary environmental pollution. Summary of the Invention

[0005] In order to achieve efficient crushing, effective dust suppression, and precise sorting in the recycling of waste concrete, this application provides a waste concrete recycling and reuse device and method.

[0006] This application provides a device and method for recycling and reusing waste concrete, which adopts the following technical solution: A waste concrete recycling and reuse device includes components connected sequentially along the material processing direction: A pretreatment unit for receiving and pretreating waste materials includes a vibrating feeder, a microwave heating cavity disposed at the discharge end of the vibrating feeder, and a material diversion mechanism disposed at the discharge end of the microwave heating cavity. A multi-stage crushing unit is used to crush pre-treated materials, including a primary crusher connected to the first output end of the material diversion mechanism, a secondary crusher connected to both the second output end of the material diversion mechanism and the discharge end of the primary crusher, and a shaping crusher connected to the discharge end of the secondary crusher. A screening unit is used to classify the crushed aggregate, including a screening mechanism connected to the discharge end of the shaping crusher, wherein the screening mechanism is provided with multiple layers of screens. The return material mechanism is used to send oversized materials back to the crushing unit. The inlet of the return material mechanism receives the largest particle size material separated by the screening mechanism, and the outlet of the return material mechanism is connected to the feed inlet of the secondary crusher. An aggregate purification unit is used to separate metallic impurities from aggregates, including a magnetic separation mechanism disposed on the qualified aggregate discharge path of the screening mechanism. A dust removal unit is used to collect and process industrial dust. The dust removal unit is connected to each dust-generating point of the device through a gas collection pipe. The cleaning unit, used to clean the mud adhering to the inside of the equipment, includes a steam generator connected to each crushing mechanism via pipelines.

[0007] By adopting the above technical solutions, in the pretreatment unit, the vibrating feeder ensures uniform material input and avoids blockage; the microwave heating chamber softens viscous materials such as asphalt concrete, reducing subsequent crushing energy consumption; the material diversion mechanism guides materials to different crushing paths according to their characteristics, improving the targeting of processing; the primary crusher processes large pieces of material, the secondary crusher receives diverted materials and primary crushing products, and the shaping crusher further optimizes the aggregate particle size distribution; the multi-layer screen of the screening unit accurately grades the aggregate, and oversized materials are returned to the secondary crusher for reprocessing through a closed-loop return mechanism, ensuring that the final aggregate particle size meets the requirements for recycling; the magnetic separation mechanism of the aggregate purification unit separates metal impurities in real time on the qualified aggregate output path; the dust removal unit covers all dust-generating points through the gas collection pipeline, effectively collecting dust during crushing, screening, and transportation; the steam generator of the cleaning unit periodically introduces steam into the crushing mechanism to soften the internal adhering mud, and with manual or automatic cleaning, it can maintain the equipment in good operating condition, extend its service life, and reduce maintenance costs.

[0008] Preferably, a temperature sensing element is provided inside the microwave heating cavity, and the material diversion mechanism is an electric diversion plate, which can adjust its angle according to the signal from the temperature sensing element.

[0009] By adopting the above technical solution, the temperature sensing element installed in the microwave heating cavity can monitor the heating status of the material in real time and accurately reflect the softening degree of viscous materials such as asphalt concrete. This avoids the material becoming too hard due to insufficient heating, which would increase crushing energy consumption, or the asphalt components aging due to excessive heating, which would reduce regeneration performance. The electric diversion plate dynamically adjusts its angle based on the temperature signal to realize the automatic switching of the material diversion path. When the asphalt concrete is detected to have softened to the standard, the diversion plate guides the secondary crusher for targeted crushing. If it is ordinary block concrete, it is guided to the primary crusher for coarse crushing.

[0010] Preferably, the primary crusher is a jaw crusher, the secondary crusher is an impact crusher, and the shaping crusher is a vertical shaft impact crusher.

[0011] By adopting the above technical solutions, the primary jaw crusher utilizes the squeezing and crushing principle of the moving and stationary jaws. Targeting the large, high-hardness characteristics of waste concrete, it features a large crushing ratio and high feed tolerance, quickly reducing irregular block materials to 80-150mm, providing stable feed for subsequent processes. The secondary impact crusher handles the jaw crushed materials and diverted asphalt concrete. Through a combined crushing method of rotor hammer impact and impact plate rebound, it combines impact energy crushing and grinding, achieving medium crushing of medium-hardness concrete. Simultaneously, targeting the viscous agglomeration characteristics of asphalt concrete, its high-frequency impact energy effectively tears apart the agglomerate structure. The final stage vertical shaft impact crusher uses high-speed impeller rotation to project material onto the cavity liner, utilizing material self-collision to complete shaping. This corrects the aggregate particle shape to cubic or polygonal shapes, with a particle shape coefficient ≥0.8, reducing the content of needle-like and flaky particles and improving the density and strength of recycled aggregates.

[0012] Preferably, the dust removal unit includes a primary dust collector, a precision dust collector, and an induced draft fan connected in sequence. The precision dust collector is a pulse bag filter type. The dust collected by the dust removal unit is transported to the batching system for resource utilization.

[0013] By adopting the above technical solutions, the primary dust collector acts as a pre-filter, prioritizing the capture of coarse dust ≥10μm generated during crushing and screening. The precision dust collector uses a pulse bag filter structure, relying on the 0.3μm-level filtration accuracy of the PTFE membrane filter bag and the periodic cleaning mechanism to improve the ultrafine dust collection rate and ensure that the emission concentration is ≤10mg / m³. At the same time, the collected dust is directly connected to the batching system through the conveying system and reused as a silica-alumina raw material for recycled concrete. In addition, the efficient dust removal effect simultaneously reduces the accumulation of dust inside the equipment, reduces the wear rate of components such as the crusher rotor and screen, and extends the equipment maintenance cycle.

[0014] Preferably, the cleaning unit further includes a high-pressure water jet device and a sedimentation tank for treating cleaning wastewater. The steam generator includes a water replenishment system. The sedimentation tank is provided with a supernatant output end, which is connected to the water replenishment system.

[0015] By adopting the above technical solution, the high-temperature steam generated by the steam generator first penetrates and softens the cement-based mud on the crushing chamber and screen surface, reducing its adhesion strength. Then, the high-pressure water jet device uses high-pressure water flow to impact and peel off the residual mud blocks. The sedimentation tank performs solid-liquid separation on the washing wastewater. The supernatant is returned to the steam generator through the water replenishment system, realizing the recycling of water resources. In addition, the wastewater recycling reduces the amount of sludge generated, and the dewatered bottom mud can be mixed with fine aggregate for roadbed filling, further realizing the resource utilization of solid waste.

[0016] A method for recycling and reusing waste concrete includes the following steps: S1. Intelligent sorting and directional crushing: Waste materials are heated by microwaves and then diverted to different crushing paths according to their temperature characteristics after heating. Block concrete is guided to the primary crusher, while asphalt concrete recycling is directly guided to the secondary crusher. S2. Multi-stage crushing and closed-loop circulation: After being crushed by the primary crusher and the secondary crusher, the material enters the shaping crusher for particle size shaping; the shaped material enters the screening mechanism for classification, and the oversized material is returned to the secondary crusher for further crushing through the return mechanism, forming a closed-loop circulation system. S3. Aggregate purification and dust control: The qualified aggregate obtained after screening is transported to the magnetic separation mechanism to separate metal impurities. At the same time, the dust generated in each stage is collected and treated by the dust removal unit. S4. Equipment Cleaning and Sludge Resource Utilization: The cleaning unit is started regularly to clean the inside of the equipment using steam and high-pressure water jets, and the wastewater generated during cleaning is treated by sedimentation to realize the resource utilization of water and sludge.

[0017] By adopting the above technical solutions, in step S1, microwave heating combined with temperature sensing diversion accurately adapts to the characteristics of materials, solving the problems of low efficiency and performance loss caused by mixed material processing; in step S2, the multi-stage crushing closed-loop circulation returns the oversized materials after shaping to the secondary crusher for further processing, which avoids aggregate gradation disorder caused by over-crushing and ensures that the final aggregate particle size meets the recycling requirements; in step S3, aggregate purification and dust control, the magnetic separation mechanism separates metal impurities in real time, so that the impurity content of recycled aggregate meets the C40 recycled concrete raw material standard, and the dust collected by the dust removal unit is reused for batching, realizing zero dust emission and raw material recycling; in step S4, equipment cleaning and resource utilization, steam softening and high-pressure water jet thoroughly remove the mud from the crushing chamber, the supernatant of the cleaning wastewater is circulated and replenished after sedimentation, and the bottom mud is mixed with fine aggregate for use in the roadbed, which not only extends the equipment maintenance cycle, but also transforms solid waste into secondary resources.

[0018] Preferably, in step S1, the threshold for determining the temperature characteristic is 80°C to 100°C.

[0019] By adopting the above technical solution, when recycled asphalt concrete is heated to 80-100℃, the asphalt components soften but do not undergo thermal decomposition. This eliminates the sticky agglomeration of the material while preserving the road performance potential of the recycled asphalt. It can be efficiently dispersed after entering the secondary crusher. For block concrete, its mineral structure is stable within this temperature range and does not become excessively embrittled or weakened due to heating. The compression crushing of the primary jaw crusher can achieve uniform volume reduction with lower energy consumption.

[0020] Preferably, in step S2, the material returned by the return mechanism is mixed and crushed together with the material that directly enters the secondary crusher from the material diversion mechanism.

[0021] Through the above technical solution, the oversized material returned by the return material mechanism is mixed with the material directly entering the secondary crusher by the diversion mechanism. The small-diameter material fills the gaps between the large-diameter particles, and the impact energy of the hammer and the impact plate can be more fully utilized for material crushing. At the same time, the hardness distribution of the mixed material is more uniform, avoiding concentrated wear on the crusher components by a single hard material. In addition, the secondary crushing of oversized material and the secondary crushing of diverted material are carried out simultaneously, eliminating the risk of over-crushing when the return material is crushed alone, and improving the particle shape coefficient of aggregate shaping. The mixed crushing stabilizes the feeding state of the secondary crusher, avoids equipment load fluctuations caused by sudden changes in material particle size, and reduces equipment maintenance costs.

[0022] Preferably, in step S3, the dust collected by the dust removal unit is reused as an auxiliary cementing material or fine aggregate in a predetermined proportion during the building material production process.

[0023] Through the above technical solution, the dust collected by the dust removal unit mainly consists of silica-alumina particles and cement clinker microspheres from waste concrete. Its mineral composition is highly compatible with traditional building material raw materials. When used as fine aggregate, its ≤5mm particle size and relatively rounded particle shape can fill the gaps between recycled aggregates, improve the density of the mixture, and reduce the bleeding rate.

[0024] Preferably, in step S4, the sediment produced by the sedimentation treatment is dewatered and then mixed with the screened fine aggregate for use in roadbed filling and other engineering projects.

[0025] Through the above technical solution, the bottom mud generated by the cleaning unit originates from the sedimentation of wastewater from washing concrete fragments. It mainly contains cement paste, fine sand, and trace aggregate particles, which would normally be disposed of as solid waste in landfills. After dewatering, it is mixed with sieved fine aggregate ≤5mm. The gaps between the fine aggregate particles are filled by the bottom mud, and at the same time, the cement-based cementitious components in the bottom mud undergo a hydration reaction during compaction, increasing the density of the mixture.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. In the pretreatment unit, the vibrating feeder ensures uniform material input and avoids blockage; the microwave heating chamber softens viscous materials such as asphalt concrete, reducing subsequent crushing energy consumption; the material diversion mechanism guides materials to different crushing paths according to their characteristics, improving the targeting of processing; the primary crusher processes large pieces of material, the secondary crusher receives diverted materials and primary crushing products, and the shaping crusher further optimizes the aggregate particle size distribution; the multi-layer screen in the screening unit accurately grades the aggregate, and oversized materials are returned to the secondary crusher for reprocessing through a closed-loop return mechanism to ensure that the final aggregate particle size meets the requirements for recycling; the magnetic separation mechanism in the aggregate purification unit separates metal impurities in real time on the qualified aggregate output path; the dust removal unit covers all dust-generating points through the air collection pipeline, effectively collecting dust during crushing, screening, and transportation; the steam generator in the cleaning unit periodically introduces steam into the crushing mechanism to soften the internal adhering mud, and with manual or automatic cleaning, it can maintain the equipment in good operating condition, extend its service life, and reduce maintenance costs.

[0027] 2. In step S1, microwave heating combined with temperature sensing diversion precisely adapts to the characteristics of the material, solving the problems of low efficiency and performance loss caused by mixed material processing. In step S2, the multi-stage crushing closed-loop circulation returns the oversized material after shaping to the secondary crusher for further processing, which avoids aggregate gradation disorder caused by over-crushing and ensures that the final aggregate particle size meets the recycling requirements. In step S3, aggregate purification and dust control use a magnetic separation mechanism to separate metal impurities in real time, so that the impurity content of the recycled aggregate meets the C40 recycled concrete raw material standard. At the same time, the dust collected by the dust removal unit is reused for batching, achieving zero dust emission and raw material recycling. In step S4, equipment cleaning and resource utilization use steam softening and high-pressure water jet to thoroughly remove mud from the crushing chamber. After the cleaning wastewater settles, the supernatant is circulated for water replenishment. The bottom mud is mixed with fine aggregate for use in the roadbed, which not only extends the equipment maintenance cycle but also transforms solid waste into secondary resources. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the waste concrete recycling and reuse device in the embodiments of this application; Figure 2 This is a flowchart of the steps in the waste concrete recycling and reuse method in the embodiments of this application.

[0029] Explanation of reference numerals in the attached drawings: 1. Pre-treatment unit; 11. Vibrating feeder; 12. Microwave heating chamber; 121. Temperature sensing element; 13. Material diversion mechanism; 2. Multi-stage crushing unit; 21. Primary crusher; 22. Secondary crusher; 23. Shaping crusher; 3. Screening unit; 31. Screening mechanism; 32. Multi-layer screen; 4. Return material mechanism; 5. Aggregate purification unit; 6. Magnetic separation mechanism; 7. Dust removal unit; 71. Primary dust collector; 72. Precision dust collector; 73. Exhaust fan; 8. Gas collection pipeline; 9. Cleaning unit; 91. Steam generator; 911. Water replenishment system; 92. High-pressure water jet device; 93. Sedimentation tank; 931. Supernatant output end. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0031] This application discloses a device for recycling and reusing waste concrete. (Refer to...) Figure 1 The waste concrete recycling and reuse device includes a pretreatment unit 1, a multi-stage crushing unit 2, a screening unit 3, a return material mechanism 4, an aggregate purification unit 5, a dust removal unit 7, and a cleaning unit 9, which are connected in sequence along the material processing direction.

[0032] The pretreatment unit 1 is used to receive and pre-process waste materials, including a vibrating feeder 11, a microwave heating cavity 12 located at the discharge end of the vibrating feeder 11, and a material diversion mechanism 13 located at the discharge end of the microwave heating cavity 12. In the pretreatment unit 1, the vibrating feeder 11 ensures uniform material input and avoids blockage; the microwave heating cavity 12 performs softening pretreatment on viscous materials such as asphalt concrete to reduce subsequent crushing energy consumption; and the material diversion mechanism 13 guides the material to different crushing paths according to its characteristics, improving the targeted processing. A temperature sensing element 121 is installed inside the microwave heating cavity 12, and the material diversion mechanism 13 is an electric diversion plate that can adjust its angle according to the signal from the temperature sensing element 121. The temperature sensing element 121 inside the microwave heating cavity 12 can monitor the material heating status in real time, accurately reflecting the softening degree of viscous materials such as asphalt concrete, such as a suitable crushing temperature of 80-100℃, avoiding insufficient heating leading to excessively hard material and increased crushing energy consumption, or excessive heating causing asphalt components to age and reduce regeneration performance.

[0033] The electric diversion plate dynamically adjusts its angle based on temperature signals, enabling automatic switching of material diversion paths. When the asphalt concrete is detected to have softened to the required level, the diversion plate guides it to the secondary crusher 22 for targeted breaking down. If it is ordinary blocky concrete, it is guided to the primary crusher 21 for coarse crushing. This solves the problems of traditional fixed diversion methods, which require manual intervention and are prone to mismatch in crushing paths due to material misjudgment. In summary, the above structure not only improves the adaptability to different materials but also, through the closed-loop combination of precise temperature control and intelligent diversion, makes the pre-treated material state more uniform and stable, providing better input conditions for the subsequent multi-stage crushing unit 2. Ultimately, this reduces overall energy consumption, minimizes abnormal equipment wear, and significantly improves the efficiency and quality of waste concrete recycling.

[0034] The multi-stage crushing unit 2 includes a primary crusher 21 connected to the first output end of the material diversion mechanism 13, a secondary crusher 22 connected to both the second output end of the material diversion mechanism 13 and the discharge end of the primary crusher 21, and a shaping crusher 23 connected to the discharge end of the secondary crusher 22. The multi-stage crushing unit 2 is used to crush the pre-treated material. The multi-stage crushing unit 2 adopts a three-stage crushing process: the primary crusher 21 processes large pieces of material, the secondary crusher 22 receives the diverted material and the primary crushing products, and the shaping crusher 23 further optimizes the aggregate particle size distribution. The three stages work together to avoid over-crushing or insufficient processing by a single crusher, significantly improving crushing efficiency. The primary crusher 21 is a jaw crusher, the secondary crusher 22 is an impact crusher, and the shaping crusher 23 is a vertical shaft impact crusher.

[0035] The primary jaw crusher utilizes the compression crushing principle of the moving and stationary jaws. Targeting the large, high-hardness characteristics of waste concrete, it features a large crushing ratio and high feed tolerance, quickly reducing irregularly shaped materials to 80-150mm, providing stable feed for subsequent processes. The maximum crushing ratio is 6-8:1. The secondary impact crusher handles the jaw crushed materials and diverted asphalt concrete. Through a combined crushing method of rotor hammer impact and impact plate rebound, it combines impact energy crushing and grinding effects, achieving medium-hardness concrete with a discharge size ≤50mm. Simultaneously, targeting the sticky, agglomerated characteristics of asphalt concrete, its high-frequency impact energy effectively tears apart the agglomerated structure. The final stage vertical shaft impact crusher uses a high-speed rotating impeller to project material onto the cavity liner. Material self-collision completes the shaping, correcting aggregate particle shape to cubic or polygonal shapes with a particle shape coefficient ≥0.8, significantly reducing the content of needle-like and flaky particles, and improving the density and strength of recycled aggregates.

[0036] The screening unit 3 includes a screening mechanism 31 connected to the discharge end of the shaping crusher 23. The screening mechanism 31 has multiple layers of screens 32 inside. The screening unit 3 is used to classify the crushed aggregate. The multiple layers of screens 32 in the screening unit 3 accurately classify the aggregate. Oversized materials are returned to the secondary crusher 22 for reprocessing via a closed-loop return mechanism 4, forming a dynamic adjustment mechanism of crushing-screening-returning to ensure that the final aggregate particle size meets the requirements for recycling. The return mechanism 4 is used to send oversized materials back to the crushing unit. The inlet of the return mechanism 4 receives the largest particle size material separated by the screening mechanism 31, and the outlet of the return mechanism 4 is connected to the feed inlet of the secondary crusher 22. The aggregate purification unit 5 includes a magnetic separator 6 installed on the qualified aggregate discharge path of the screening mechanism 31. The aggregate purification unit 5 is used to separate metallic impurities from the aggregate. The magnetic separator 6 of the aggregate purification unit 5 separates metallic impurities in real time on the qualified aggregate output path, significantly improving the purity of the recycled aggregate and meeting the raw material requirements of high-quality recycled concrete.

[0037] The dust removal unit 7 includes a primary dust collector 71, a precision dust collector 72, and an induced draft fan 73 connected in sequence. The precision dust collector 72 is a pulse-jet bag filter. The primary dust collector 71 acts as a pre-filter, preferentially capturing coarse dust particles ≥10μm generated during the crushing and screening processes, reducing the processing load of the subsequent precision dust collector by 40%-50% and ensuring stable system operation. The precision dust collector adopts a pulse-jet bag filter structure, relying on the 0.3μm-level filtration accuracy of the PTFE membrane filter bags and a periodic cleaning mechanism, which can increase the ultrafine dust collection rate to over 99%, ensuring an emission concentration ≤10mg / m³, completely solving the air pollution problem caused by leakage in traditional dust removal systems. Simultaneously, the cement clinker and silica particles contained in the dust can replace some natural sand and gravel. For every 100 tons of waste concrete processed, 5-8 tons of dust can be recycled, equivalent to saving 0.8-1.2 tons of natural sand and gravel, reducing raw material waste and lowering the production cost of recycled concrete. In addition, the efficient dust removal effect simultaneously reduces the accumulation of dust inside the equipment, reduces the wear rate of components such as the crusher rotor and screen, and extends the equipment maintenance cycle.

[0038] Dust removal unit 7 is used to collect and process production dust. Dust removal unit 7 is connected to each dust-generating point of the device through gas collection pipe 8. The dust collected by dust removal unit 7 is transported to the batching system for resource utilization. Dust removal unit 7 covers all dust-generating points through gas collection pipe 8, effectively collecting dust during crushing, screening and transfer processes. With subsequent treatment, it can achieve low emissions and avoid secondary pollution.

[0039] The cleaning unit 9 includes a steam generator 91 connected to each crushing mechanism via pipelines. The cleaning unit 9 is used to remove mud adhering to the inside of the equipment. The steam generator 91 of the cleaning unit 9 periodically supplies steam to the crushing mechanism to soften the adhering mud. Combined with manual or automatic cleaning, this maintains good equipment operation, extends service life, and reduces maintenance costs. The cleaning unit 9 also includes a high-pressure water jet device 92 and a sedimentation tank 93 for treating cleaning wastewater. The steam generator 91 includes a water replenishment system 911, and the sedimentation tank 93 has a supernatant output end 931 connected to the water replenishment system 911.

[0040] The high-temperature steam generated by the steam generator 91 first penetrates and softens the cement-based mud on the crushing chamber and screen surface, reducing its adhesion strength. Then, the high-pressure water jet device 92 uses high-pressure water jets to impact and peel off residual mud. This synergistic effect, compared to steam or water washing alone, improves the mud removal rate and solves the problem of stubborn mud adhesion causing equipment blockage and affecting crushing efficiency in traditional washing methods. The high-temperature steam temperature is 120-150℃, and the high-pressure water jet device pressure is 5-8MPa. The sedimentation tank 93 performs solid-liquid separation on the washing wastewater. The supernatant is returned to the steam generator 91 through the water replenishment system 911, avoiding soil / water pollution caused by direct wastewater discharge. Specifically, the suspended solids concentration is ≤500mg / L, conforming to GB 8978-1996. Furthermore, wastewater recycling reduces sludge production, and the dewatered bottom sludge can be mixed with fine aggregate for roadbed filling, further realizing the resource utilization of solid waste.

[0041] Reference Figure 2 A method for recycling and reusing waste concrete includes the following steps: S1. Intelligent sorting and directional crushing: Waste materials are heated by microwaves and diverted to different crushing paths according to the temperature characteristics after heating. Block concrete is guided to the primary crusher 21, while asphalt concrete recycling is directly guided to the secondary crusher 22.

[0042] Among them, microwave heating combined with temperature sensing and diversion can be precisely adapted to the characteristics of materials. That is, block concrete is efficiently coarsely crushed by the primary jaw crusher, and asphalt concrete directly enters the secondary impact crusher to avoid overheating and aging, thus solving the problems of low efficiency and performance loss caused by mixed material processing.

[0043] In an optional embodiment, the threshold for determining the temperature characteristics is 80°C to 100°C. For recycled asphalt concrete, when heated to 80-100°C, the asphalt components soften but do not undergo thermal decomposition, which eliminates the sticky agglomeration of the material while preserving the road performance potential of the recycled asphalt. After entering the secondary crusher 22, it can be efficiently dispersed. For block concrete, its mineral structure is stable within this temperature range, and it does not become excessively embrittled or weakened due to heating. The compression crushing of the primary jaw crusher can achieve uniform volume reduction with lower energy consumption.

[0044] S2. Multi-stage crushing and closed-loop circulation: After being crushed by the primary crusher 21 and the secondary crusher 22, the material enters the shaping crusher 23 for particle size shaping; the shaped material enters the screening mechanism 31 for grading, and the oversized material is returned to the secondary crusher 22 for further crushing through the return mechanism 4, forming a closed-loop circulation system.

[0045] In this process, the oversized material after shaping is returned to the secondary crusher 22 for further processing, forming a dynamic adjustment chain of coarse crushing-medium crushing-shaping-screening-returning. This not only avoids aggregate gradation disorder caused by over-crushing, but also ensures that the final aggregate particle size meets the recycling requirements, reducing subsequent screening costs.

[0046] In an optional embodiment, the material returned by the return mechanism 4 is mixed and crushed together with the material that enters the secondary crusher 22 directly from the material diversion mechanism 13. The oversized materials (such as aggregates >50mm) returned by the return material mechanism 4 are mixed with the materials (such as asphalt concrete or materials ≤150mm after primary crushing) that directly enter the secondary crusher 22 from the diversion mechanism. The small-diameter materials fill the gaps between the large-diameter materials, increasing the cavity filling rate of the impact crusher. The impact energy of the hammer and impact plate can be more fully utilized for material crushing, improving crushing efficiency. At the same time, the hardness distribution of the mixed materials is more uniform, that is, the soft asphalt of the asphalt concrete and the hard aggregate of the concrete are interwoven, avoiding concentrated wear of the crusher parts by a single hard material, and extending the service life of the impact plate and hammer. In addition, the secondary crushing of oversized materials and the secondary crushing of diverted materials are carried out simultaneously, eliminating the risk of over-crushing when the return material is crushed alone, so that the final output particle size is more concentrated in 30-50mm, providing uniform input for the subsequent shaping crusher 23, improving the particle shape coefficient of aggregate shaping (≥0.85). The mixed crushing stabilizes the feeding state of the secondary crusher 22, avoids equipment load fluctuations caused by sudden changes in material particle size, and reduces equipment maintenance costs.

[0047] S3. Aggregate purification and dust control: The qualified aggregate obtained after screening is transported to the magnetic separation unit 6 to separate metal impurities. At the same time, the dust generated in each stage is collected and treated by the dust removal unit 7.

[0048] Among them, the magnetic separation unit 6 separates metal impurities in real time with a separation efficiency of ≥98%, reducing the impurity content of recycled aggregate to below 0.5%, which meets the C40 recycled concrete raw material standard. At the same time, the dust collected by the dust removal unit 7 is recycled for batching, saving 0.15 tons of natural sand and gravel per ton of concrete, achieving zero dust emission and raw material recycling.

[0049] In an optional embodiment, the dust collected by dust removal unit 7 is recycled into the building material production process as an auxiliary cementitious material or fine aggregate in a predetermined proportion. The dust collected by dust removal unit 7 mainly consists of silica-alumina particles and cement clinker microspheres from waste concrete. Its mineral composition is highly compatible with traditional building material raw materials. When used as an auxiliary cementitious material in a predetermined proportion (10%-15%), it can react with calcium hydroxide, a cement hydration product, to generate additional cementitious substances, enhancing the impermeability and later-stage strength of concrete. When used as fine aggregate, its ≤5mm particle size and relatively rounded particle shape can fill the voids between recycled aggregates, improving the density of the mixture and reducing the bleeding rate. The operation of dust removal unit 7 reduces secondary air pollution from dust emissions and lowers the raw material costs of building material production.

[0050] S4. Equipment Cleaning and Sludge Resource Utilization: Regularly start the cleaning unit 9 to clean the inside of the equipment using steam and high-pressure water jets, and treat the wastewater generated during cleaning by sedimentation to achieve resource utilization of water and sludge.

[0051] Among them, steam softening and high-pressure water jet thoroughly remove mud from the crushing chamber, with a removal rate of ≥95%. After the washing wastewater settles, the supernatant is circulated for water replenishment. The bottom mud is mixed with fine aggregate for use in the roadbed, and the compressive strength meets the C15 standard. This not only extends the equipment maintenance cycle but also transforms solid waste into secondary resources.

[0052] In an optional embodiment, the sediment generated from the sedimentation treatment is dewatered and mixed with the screened fine aggregate for use in roadbed filling and other engineering projects. The sediment generated by the washing unit 9 originates from the sedimentation of wastewater from washing concrete fragments and mainly contains cement paste, fine sand, and trace aggregate particles, which would normally be disposed of as solid waste in landfills. After dewatering, it is mixed with the screened ≤5mm fine aggregate. The gaps between the fine aggregate particles are filled by the sediment, and at the same time, the cement-based cementitious components in the sediment undergo a hydration reaction during compaction, increasing the density of the mixture and enhancing its compressibility. Optionally, the CBR value can reach 8%-10%, meeting the Class II filler standard for roadbed base courses.

[0053] The implementation principle of this application embodiment is as follows: In the pretreatment unit 1, the vibrating feeder 11 ensures uniform material input and avoids blockage; the microwave heating chamber 12 performs softening pretreatment on viscous materials such as asphalt concrete to reduce subsequent crushing energy consumption; the material diversion mechanism 13 guides the material to different crushing paths according to its characteristics, improving the processing targeting; the primary crusher 21 processes large pieces of material, the secondary crusher 22 receives the diverted material and the primary crushing products, and the shaping crusher 23 further optimizes the aggregate particle size distribution; the multi-layer screen 32 of the screening unit 3 accurately grades the aggregate. Oversized materials are returned to the secondary crusher 22 in a closed loop via the return mechanism 4 for further processing, ensuring that the final aggregate particle size meets the requirements for recycling. The magnetic separation mechanism 6 of the aggregate purification unit 5 separates metal impurities in real time on the qualified aggregate output path. The dust removal unit 7 covers all dust-generating points through the gas collection pipe 8, effectively collecting dust during crushing, screening and transportation. The steam generator 91 of the cleaning unit 9 periodically introduces steam into the crushing mechanism to soften the internal adhering mud. Combined with manual or automatic cleaning, it can maintain the good operating condition of the equipment, extend its service life and reduce maintenance costs.

[0054] In step S1, microwave heating combined with temperature sensing diversion precisely adapts to the material characteristics, solving the problems of low efficiency and performance loss caused by mixed material processing. In step S2, the multi-stage crushing closed-loop circulation returns the oversized material after shaping to the secondary crusher 22 for further processing, which avoids aggregate gradation disorder caused by over-crushing and ensures that the final aggregate particle size meets the recycling requirements. In step S3, aggregate purification and dust control, the magnetic separation mechanism 6 separates metal impurities in real time, so that the impurity content of recycled aggregate meets the C40 recycled concrete raw material standard. At the same time, the dust collected by the dust removal unit 7 is recycled for batching, realizing zero dust emission and raw material recycling. In step S4, equipment cleaning and resource utilization, steam softening and high-pressure water jet thoroughly remove the mud from the crushing chamber. After the cleaning wastewater settles, the supernatant is circulated for water replenishment. The bottom mud and fine aggregate are mixed for roadbed, which not only extends the equipment maintenance cycle, but also transforms solid waste into secondary resources.

[0055] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A waste concrete recycling and reuse device, characterized in that, Including those connected sequentially along the material handling direction: The pretreatment unit (1) is used to receive and pretreat waste materials, including a vibrating feeder (11), a microwave heating cavity (12) disposed at the discharge end of the vibrating feeder (11), and a material diversion mechanism (13) disposed at the discharge end of the microwave heating cavity (12). The multi-stage crushing unit (2) is used to crush the pre-treated material, including a primary crusher (21) connected to the first output end of the material diversion mechanism (13), a secondary crusher (22) connected to both the second output end of the material diversion mechanism (13) and the discharge end of the primary crusher (21), and a shaping crusher (23) connected to the discharge end of the secondary crusher (22); The screening unit (3) is used to classify the crushed aggregate, including a screening mechanism (31) connected to the discharge end of the shaping crusher (23), and the screening mechanism (31) is provided with multiple layers of screens (32). The return material mechanism (4) is used to send oversized materials back to the crushing unit. The inlet of the return material mechanism (4) receives the largest particle size material separated by the screening mechanism (31), and the outlet of the return material mechanism (4) is connected to the feed port of the secondary crusher (22). Aggregate purification unit (5) is used to separate metal impurities in aggregates, including magnetic separation mechanism (6) set on the qualified aggregate discharge path of the screening mechanism (31); A dust removal unit (7) is used to collect and process industrial dust. The dust removal unit (7) is connected to each dust-generating point of the device through a gas collection pipe (8). The cleaning unit (9) is used to clean the mud adhering to the inside of the equipment, including a steam generator (91) connected to each crushing mechanism via pipeline.

2. The waste concrete recycling and reuse device according to claim 1, characterized in that, The microwave heating cavity (12) is provided with a temperature sensing element (121), and the material diversion mechanism (13) is an electric diversion plate. The material diversion mechanism (13) can adjust its angle according to the signal of the temperature sensing element (121).

3. The waste concrete recycling and reuse device according to claim 1, characterized in that, The primary crusher (21) is a jaw crusher, the secondary crusher (22) is an impact crusher, and the shaping crusher (23) is a vertical shaft impact crusher.

4. The waste concrete recycling and reuse device according to claim 1, characterized in that, The dust removal unit (7) includes a primary dust collector (71), a precision dust collector (72) and an induced draft fan (73) connected in sequence. The precision dust collector (72) is a pulse bag filter type. The dust collected by the dust removal unit (7) is transported to the batching system for resource utilization.

5. The waste concrete recycling and reuse device according to claim 1, characterized in that, The cleaning unit (9) also includes a high-pressure water jet device (92) and a sedimentation tank (93) for treating cleaning wastewater. The steam generator (91) includes a water replenishment system (911). The sedimentation tank (93) is provided with a supernatant output end (931), which is connected to the water replenishment system (911).

6. A method for recycling and reusing waste concrete, utilizing the waste concrete recycling and reusing device according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Intelligent sorting and directional crushing: Waste materials are heated by microwaves and diverted to different crushing paths according to the temperature characteristics after heating. Among them, block concrete is guided to the primary crusher (21), while asphalt concrete recycling is directly guided to the secondary crusher (22). S2, Multi-stage crushing and closed-loop circulation: After being crushed by the primary crusher (21) and the secondary crusher (22), the material enters the shaping crusher (23) for particle size shaping; the shaped material enters the screening mechanism (31) for grading, and the oversized material is returned to the secondary crusher (22) for re-crushing through the return mechanism (4) to form a closed-loop circulation system; S3. Aggregate purification and dust control: The qualified aggregate obtained after screening is transported to the magnetic separation mechanism (6) to separate metal impurities. At the same time, the dust generated in each stage is collected and treated by the dust removal unit (7). S4. Equipment cleaning and mud resource utilization: The cleaning unit (9) is started regularly to clean the inside of the equipment using steam and high-pressure water jets, and the wastewater generated during cleaning is treated by sedimentation to realize the resource utilization of water and mud.

7. The method for recycling and reusing waste concrete according to claim 6, characterized in that, In step S1, the threshold for determining the temperature characteristic is 80°C to 100°C.

8. The waste concrete recycling and reuse device according to claim 6, characterized in that, In step S2, the material returned by the return mechanism (4) is mixed and crushed together with the material that directly enters the secondary crusher (22) from the material diversion mechanism (13).

9. The waste concrete recycling and reuse device according to claim 6, characterized in that, In step S3, the dust collected by the dust removal unit (7) is used as an auxiliary cementing material or fine aggregate and recycled in a predetermined proportion in the building material production process.

10. The method for recycling and reusing waste concrete according to claim 6, characterized in that, In step S4, the sediment produced by the sedimentation treatment is dewatered and mixed with the screened fine aggregate for use in roadbed filling and other engineering projects.

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