A method for multi-stage sorting pretreatment and aggregate modification treatment of decoration mixed solid waste

Abstract

The present application relates to the technical field of building solid waste resource recycling, and particularly discloses a mixed solid waste multi-stage separation pretreatment and aggregate modification treatment method, which comprises the following steps: S1, raw material pre-screening pretreatment, which is used for separating slag, light impurities and removing metal impurities by magnetic separation, and completing preliminary purification of the raw material; S2, multi-stage crushing, grading and separation, which is used for crushing and shaping the aggregate and realizing fine grading and impurity removal by matching air separation and color separation, so as to obtain a multi-stage aggregate semi-finished product. In the present application, a unique aggregate cleaning and activation matching swing dynamic modification process is adopted, high-pressure drum cleaning is used to remove the mud and dust on the surface of the aggregate, the moisture content is controlled within 2% in the hot air drying kiln, the drum micro-polishing machine group is used to break the dense inert hydration layer on the surface of the aggregate by friction, and the surface opening porosity of the aggregate is effectively improved, so as to provide sufficient attachment sites for the penetration of the modified solvent.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology for construction solid waste, and in particular to a method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification. Background Technology

[0002] The current modification process for preparing recycled aggregates from mixed solid waste from renovation projects, after sorting and crushing, generally suffers from the core defect that the modifying solvents cannot achieve a comprehensive and uniform coating of the aggregates.

[0003] Currently, the mainstream modification methods in the industry mostly adopt two modes: static immersion and fixed-nozzle unidirectional spraying. During the modification process, the aggregate is in a static, piled-up state, with particles stacked and obstructing each other. The bottom surface of the aggregate, the gaps between particles, and the concave corners cannot fully contact the modifying solvent. Only the outer surface of the aggregate can contact the atomized or liquid modifying agent, and the internal piled aggregate is prone to large-area incomplete coating. Conventional spraying devices have poor atomization effects and large droplet size differences, which easily lead to the polarization problem of local excessive agent accumulation and local lack of agent coverage, making it difficult to control the uniformity of coating. Therefore, in order to solve these problems, a multi-stage sorting and pretreatment method for mixed solid waste from construction and decoration and aggregate modification treatment is proposed. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a multi-stage sorting and pretreatment method for mixed solid waste from renovation and aggregate modification.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for multi-stage sorting and pretreatment of mixed solid waste from construction and its aggregate modification, characterized in that the method includes the following steps:

[0007] S1 raw material pre-screening and pretreatment is used to separate slag, light impurities and remove metal impurities by magnetic separation, thus completing the initial purification of raw materials;

[0008] S2 multi-stage crushing, grading and sorting is used to crush and shape aggregates and, together with air classification and color classification, achieves fine grading and impurity removal to obtain multi-stage aggregate semi-finished products;

[0009] S3 aggregate cleaning and activation treatment is used to clean and dry aggregates and grind away the surface inert layer to improve aggregate bonding activity.

[0010] The S4 aggregate jumping device is installed to replace the adapted small screen and ensure that the aggregate remains on the screen and does not fall off.

[0011] S5 aggregate is added to the gyratory pellet mill to evenly distribute activated aggregate onto the screen surface of the gyratory pellet mill.

[0012] The S6 aggregate modification nozzle assembly is used to install detachable atomizing nozzles at the equipment inlet to match spray modification operations;

[0013] S7 Aggregate Modification Solvent Preparation: This is used to select inorganic or organic modification solvents according to the aggregate application scenario.

[0014] S8 aggregate modification treatment is used for high-frequency jumping synchronous atomization spraying of aggregates to achieve all-round coating of aggregates by modification solvents;

[0015] S9 aggregate modification post-treatment is used for constant temperature static curing of aggregates to allow the modified components to fully penetrate and solidify.

[0016] S10 post-sizing screening is used for secondary screening and air drying to remove unqualified particles and produce high-quality modified recycled aggregate.

[0017] Preferably, the pre-screening and pretreatment of raw material S1 is as follows:

[0018] First, bagged debris and oversized lumps are manually removed, and then the materials are fed into a conveying and screening equipment for primary screening to separate the original slag, light organic impurities, and mixed hard solid waste. At the same time, the magnetic separation equipment adsorbs and removes metal impurities such as iron wires and steel nails from the mixed hard solid waste.

[0019] The S2 multi-stage crushing, grading and sorting process is as follows: the purified mixed hard solid waste is sent to the multi-stage crushing and shaping unit, where it is crushed in sequence, then crushed in a coarse, medium and fine manner, and shaped into particles to optimize the aggregate shape and reduce the proportion of needle-shaped and flaky particles. The aggregate is then separated into three grades of recycled aggregate semi-finished products according to particle size by multi-stage screening equipment. At the same time, air classification and photoelectric color classification processes are used to remove residual light impurities and discolored inert impurities.

[0020] Preferably, the S3 aggregate cleaning and activation treatment involves sending the graded aggregate semi-finished product into a cleaning and dust removal equipment to remove mud and dust, drying it to the standard moisture content, and then micro-grinding the dense inert layer on the surface of the aggregate.

[0021] S4 Remove the original screen of the swing pellet mill and replace it with a custom screen with a screen hole smaller than the diameter of the aggregate particles.

[0022] S5 lays the activated aggregate flat on the screen of the gyratory pellet mill;

[0023] The S6 can be detachably fitted with an atomizing nozzle at the feed inlet of the oscillating pellet mill, which is compatible with the size and shape of the feed inlet.

[0024] S7 selects inorganic cementitious modifiers or organic functional modifiers based on the downstream application requirements of aggregates;

[0025] The S8 start-up oscillating pellet mill drives the aggregate to bounce at high frequency, and the atomizing nozzle sprays out the modified solvent. The aggregate continuously flips and changes angle, fully contacting and wetting the atomized solvent, so as to achieve uniform coating of the modified solvent on the entire surface of the aggregate.

[0026] Preferably, the multi-stage crushing and shaping unit consists of a coarse jaw crusher, a medium and fine cone crusher, and a vertical impact shaping machine connected in series, and the proportion of needle-shaped and flaky particles in the shaped aggregate is controlled to be below 8%.

[0027] The air separator and photoelectric color sorter operate synchronously, with the air separation speed controlled at 12-18m / s and the photoelectric color sorter having high recognition accuracy.

[0028] Preferred specific process for S3 aggregate clean activation treatment:

[0029] The semi-finished aggregate is passed through a high-pressure cleaning drum to remove the mud and dust adhering to the surface. After cleaning, it is sent to a hot air drying kiln to dry until the moisture content of the aggregate is ≤2%. The dried aggregate is then sent to a drum micro-grinding unit to frictionally grind the surface layer, increasing the porosity of the aggregate surface and improving the bonding ability of the aggregate with the modified solvent.

[0030] Preferably, the atomizing nozzle adopts a two-fluid high-pressure atomization structure, with atomized droplet particle size range of 20-80μm. The nozzle is detachably connected to the feed port of the oscillating pellet mill via a flange snap-fit ​​structure, and the nozzle with the corresponding flow rate specification can be replaced according to different aggregate particle sizes.

[0031] Preferably, the modified solvent used in S7 is:

[0032] The inorganic cementitious modifier is a silica fume-fly ash composite suspension, and the organic functional modifier is a 30% solids content waterborne epoxy resin emulsion. The two modifiers can be used alone or in combination in proportion, and are suitable for different aggregate application scenarios such as roadbed backfilling, permeable bricks, and prefabricated components.

[0033] Preferably, the post-treatment of S9 aggregate modification is as follows:

[0034] After the modified coating is completed, the aggregate is transferred to a closed constant temperature curing chamber for static curing. The curing temperature is controlled at 40℃-65℃ and the curing time is 6h-24h. The curing chamber maintains a low-speed micro-ventilation environment to ensure that the modified components fully penetrate into the micropores inside the aggregate and solidify and adhere to the surface of the aggregate.

[0035] Preferably, the S10 post-treatment sieving process is as follows:

[0036] After the constant temperature curing is completed, the aggregate is sent to a double-layer vibrating screen to complete the secondary screening. The upper screen retains the agglomerated aggregate, while the lower screen separates the modified uneven fine powder. The qualified aggregate is dried and shaped by ambient temperature air cooling. The unqualified particles that are agglomerated or unevenly coated are returned to the multi-stage crushing process for reprocessing.

[0037] Preferably, the oscillating pellet mill is set to an oscillation frequency of 100-140 times / minute, with a single atomization spray modification time of 6-10 minutes. After spraying, the oscillation continues for 1-3 minutes to spread out excess modifying solvent on the aggregate surface and avoid local agent accumulation that could cause aggregate clumping.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] 1. This invention features a dual impurity removal process involving pre-screening and pre-treatment of raw materials, as well as multi-stage crushing, grading, and sorting. First, oversized impurities are manually removed. Primary screening separates slag and lightweight organic waste, while magnetic separation thoroughly removes metal components. Then, continuous processing is achieved through a coarse jaw crusher, a cone crusher for medium and fine crushing, and a vertical impact shaping unit. This process stably controls the percentage of needle-shaped and flaky aggregate particles to within 8%. Simultaneously, a 12-18 m / s wind speed air separator and a high-precision photoelectric color separator are used to thoroughly remove residual plastic, wood chips, and discolored gypsum inert impurities. The entire sorting process achieves layered and step-by-step separation of slag, light impurities, metals, and discolored waste. Compared with the traditional single-stage crushing and sorting process, the impurity removal rate is increased by more than 35%, eliminating the interference of impurities on the subsequent modification effect. The aggregate particles are regular in shape and have clear particle size classification. The coarse, medium, and fine aggregate semi-finished products can be separately activated and modified without the need for secondary manual sorting. This significantly reduces the labor intensity of manual sorting, significantly improves the continuous automated operation capability of the production line, and increases the effective purification and utilization rate of solid waste raw materials to more than 92%.

[0040] 2. This invention features a unique aggregate cleaning and activation process coupled with a dynamic oscillating modification process. High-pressure roller cleaning removes surface mud and dust from the aggregates, while a hot air drying kiln controls the moisture content to below 2%. A roller micro-grinding unit frictionally breaks down the dense, inert hydrated layer on the aggregate surface, effectively increasing the surface porosity and providing ample adhesion sites for the modifying solvent. A customized small-screen oscillating pellet mill achieves high-frequency, uniform aggregate movement, and a two-fluid high-pressure atomizing nozzle outputs uniform droplets of 20-80μm. The aggregates continuously tumble without dead angles, allowing the modifying solvent to comprehensively coat both the inner and outer surfaces of the aggregates. Compared to traditional static soaking and unidirectional spray modification methods, the uniformity of aggregate modification coating is improved by 40%, eliminating problems such as incomplete modification of internal aggregates and localized agent accumulation and clumping. Inorganic and organic modifying solvents can be used alone or in combination.

[0041] 3. The invention is equipped with a closed-loop recycling system for shaping and screening in a sealed constant temperature curing chamber. The modified and sprayed aggregate is cured in a constant temperature and low-speed micro-ventilation environment of 40-65℃ for 6-24 hours to ensure that the silica fume-fly ash inorganic suspension and water-based epoxy resin organic emulsion fully penetrate into the micropores of the aggregate and solidify, which greatly improves the interfacial bonding strength and durability of the aggregate. After curing, the double-layer vibrating screen separates the agglomerated aggregate and the modified uneven fine powder into layers. The qualified aggregate is air-dried and shaped by cold air, and the unqualified material is directly returned to the multi-stage crushing process for reprocessing to form a complete production line. Attached Figure Description

[0042] Figure 1 This is a flowchart of a method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification proposed in this invention;

[0043] Figure 2 This is a line diagram showing the subdivision of raw material pre-screening and pre-treatment in the S1 section of the multi-stage sorting and pre-treatment and aggregate modification treatment method for mixed solid waste from decoration proposed in this invention.

[0044] Figure 3 This is a detailed line diagram of the S4-S8 dynamic modification core section of a multi-stage sorting and pretreatment and aggregate modification treatment method for mixed solid waste in decoration proposed in this invention.

[0045] Figure 4 This is a wireframe diagram of the S9-S10 curing, shaping, and closed-loop recycling method for multi-stage sorting, pretreatment, and aggregate modification of mixed solid waste from renovation proposed in this invention. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0047] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] Reference Figure 1-4 A method for multi-stage sorting and pretreatment of mixed solid waste from decoration and aggregate modification treatment, the overall process is as follows: S1 raw material pre-screening and pretreatment section, S2 multi-stage crushing, grading and sorting section, S3 aggregate cleaning and activation treatment section, S4 aggregate jumping equipment modification and construction section, S5 aggregate feeding and feeding section, S6 atomizing modification nozzle assembly section, S7 modification solvent preparation and storage section, S8 dynamic synchronous atomizing modification section, S9 closed constant temperature curing section, S10 post-shaping, screening and closed-loop reuse section.

[0049] S1 Raw material pre-screening and pretreatment process

[0050] The mixed solid waste materials from the renovation are unloaded directly from the factory's dump trucks to the raw material receiving silo. A manual sorting station is set up at the entrance of the receiving silo, where two operators stand on both sides of the material conveyor belt and manually remove large debris that cannot be directly sent to the screening equipment, such as whole bags of unopened paint, complete gypsum boards, extra-long timber exceeding 50cm in length, and extra-large concrete blocks with a diameter greater than 30cm. The sorted large debris is crushed separately and then transported back to the raw material silo for recycling. After manual coarse sorting, the material is conveyed by belt conveyor to the primary drum screen. The drum screen has a screen aperture size of 10mm. The drum rotates at a uniform speed, and the original slag with a particle size of less than 10mm is directly leaked out of the screen aperture, collected and transported to the slag dump in the plant area, and can be used for site backfilling. The material on the screen is a mixture of hard solid waste and light debris. The discharge end of the drum screen is equipped with a permanent magnet drum magnetic separator. The magnetic field strength on the surface of the magnetic separator is controlled at 3500Gs. When the material passes through the magnetic separator, metal impurities such as iron wire, steel nails, rebar ends, and metal clips are adsorbed by the drum. The drum is equipped with a scraper to scrape off the metal waste at regular intervals, which is then collected and sold for recycling. The hard solid waste, plastic film, wood chips, foam and other light materials that are not adsorbed enter the next stage.

[0051] S2 Multi-stage Crushing, Grading and Sorting Process

[0052] The mixed hard solid waste purified by S1 is conveyed by belt to a multi-stage crushing and shaping unit. The unit is arranged in series with a primary jaw crusher, a secondary and secondary cone crusher, and a vertical impact shaper. The material first enters the primary jaw crusher, with a maximum processing particle size of 250mm at the jaw crusher inlet. After crushing, the particle size of the material is reduced to 0-80mm. The primary crushing output is directly fed into the secondary and secondary cone crushers, which process the material to 0-30mm. All the secondary and secondary crushing products are conveyed to the vertical impact shaper, where the particles are shaped by high-speed self-impact, eliminating sharp edges of the aggregate. After sampling and testing, the proportion of needle-shaped and flaky particles in the aggregate is stably controlled below 8% after shaping, fully meeting the particle shape standards for recycled building material aggregates. The shaped aggregate is fed into a three-layer multi-stage linear vibrating screen. The mesh sizes of the three screens are 20mm, 5mm, and 2mm from top to bottom. After screening, three types of semi-finished aggregates are obtained: 2-20mm coarse aggregate, 0.16-5mm medium aggregate, and 0-0.16mm fine aggregate. The three types of aggregates are transported to their respective activation treatment units via independent conveyor belts. A wind classifier and photoelectric color sorter are synchronously installed on the side of the screen. The air classifier fan outlet faces the material on the screen surface, and the wind speed is stably controlled at 12-18m / s. The wind force blows floating plastics, wood chips, foam, and other lightweight impurities away from the aggregate surface and collects them in a lightweight waste bin.

[0053] S3 Aggregate Cleaning and Activation Process

[0054] The graded coarse, medium, and fine aggregate semi-finished products are fed into independent high-pressure cleaning drum equipment. High-pressure spray pipes are evenly arranged inside the drums, with a spray water pressure of 0.8 MPa. The high-pressure water flow thoroughly washes away the aggregate surface, removing attached mud, dust, and gypsum powder. A wastewater collection tank is installed at the bottom of the drums; the wastewater is circulated and reused for cleaning after sedimentation and filtration, and the filtered sludge is periodically cleaned and disposed of. The cleaned wet aggregate is then conveyed to a mesh belt hot air drying kiln via a closed scraper conveyor. The kiln is heated by natural gas, maintaining a constant temperature of 110℃. The aggregate mesh belt travel speed is controlled at 0.6 m / min, and the aggregate remains in the kiln for 45 minutes to dry. A real-time online moisture content detector at the discharge end monitors the aggregate moisture content, ensuring that the output aggregate moisture content is ≤2%. If the moisture content exceeds the standard, the mesh belt travel speed is automatically reduced, extending the drying time. After drying, the aggregate is transferred to a drum micro-grinding unit. The inside of the drum is filled with wear-resistant rubber grinding liners. The drum rotates at 30 r / min. The aggregate rubs and collides with each other inside the drum, breaking down the dense inert shell formed by long-term hydration on the surface of the aggregate. After grinding, the micro-pore porosity of the aggregate surface increases by about 50%, which greatly increases the contact area between the aggregate and the modifying solvent, solving the problem that traditional unactivated aggregate modifying agents only adhere to the surface and are easy to fall off and fail.

[0055] S4, S5, and S6 equipment setup and assembly processes

[0056] A commercially available standard gyratory pellet mill is selected as the main equipment for the modification reaction. First, the original factory-installed standard screen is removed. A custom-made screen is then installed based on the aggregate particle size to be processed. The screen aperture is strictly smaller than the smallest aggregate particle diameter. For example, a 1.5mm aperture screen is used when processing 2-20mm coarse aggregate, and a 0.1mm aperture screen is used when processing 0.16-5mm medium aggregate. The screen is fixed inside the gyratory pellet mill with locking bolts to ensure that the aggregate remains on the screen surface throughout the process, preventing material loss due to falling through the screen holes. After screen replacement, the dried aggregate, after S3 activation treatment, is evenly conveyed to the gyratory pellet mill screen surface via a closed conveyor belt. The aggregate thickness for each layer is controlled at 3-5cm, ensuring uniform thickness without local accumulation or blank areas. This guarantees that each aggregate particle can fully rotate and contact the atomized agent during subsequent modification spraying. A two-fluid high-pressure atomizing nozzle is installed at the rectangular feed inlet on the top of the gyratory pellet mill. The nozzle base is equipped with a flange snap-lock sealing structure with a built-in rubber sealing gasket. Tightening the snap-lock allows for quick sealing and installation of the nozzle. Disassembly only requires loosening the snap-lock. Three flow rate specifications (large, medium, and small) nozzles can be replaced according to different aggregate sizes (coarse, medium, and fine). The nozzle adopts a two-fluid atomization structure with independent dual-channel supply of compressed air and modified solvent. By adjusting the air pressure and liquid supply pressure, it can stably output uniform atomized droplets in the range of 20-80μm, preventing large droplets from falling and causing local over-soaking and agglomeration of aggregates.

[0057] S7 modified solvent preparation and storage process

[0058] This invention includes two sets of modified solvent storage and mixing tanks, one for storing inorganic modifying agents and the other for storing organic modifying solutions. These can be used individually or mixed and compounded according to the downstream application scenario of the aggregate. For roadbed backfilling, inorganic cementitious modifying agents are preferred. The raw materials are silica fume and fly ash. Water is added at a mass ratio of silica fume:fly ash = 3:7 to prepare a composite suspension. The mixing tank is equipped with a low-speed stirring motor to continuously stir and prevent powder sedimentation and stratification. For permeable brick and municipal sidewalk building materials, organic functional modifying solutions are used. These are water-based epoxy resin emulsions with a solid content of 30% and can be used directly without dilution. For precast concrete components, inorganic suspension and epoxy emulsion are compounded at a 1:1 ratio. During compounding, the mixture is stirred at low speed in the mixing tank for 15 minutes to achieve uniform mixing. The bottom of the two mixing tanks is equipped with a metering pump, which can accurately and quantitatively deliver the modified solvent to the atomizing nozzle. The electrical control system can preset the solvent delivery flow rate to adapt to different production capacity requirements. The solvent storage tank is wrapped with an insulation layer. In low-temperature winter environments, the heating device can be turned on to prevent the epoxy resin emulsion from solidifying and failing at low temperatures.

[0059] S8 aggregate synchronous atomization modification process

[0060] After completing the fabric, nozzle assembly, and solvent preparation, start the oscillating pellet mill. Set the oscillation frequency on the equipment's control panel to 100-140 times / minute. Use a low-frequency oscillation of 100 times / minute for coarse aggregate and a high-frequency oscillation of 140 times / minute for fine aggregate. Turn on the metering pump and the compressed air valve of the atomizing nozzle to start the atomizing spray modification process. Set the spray duration for each cycle to 6-10 minutes, 10 minutes for coarse aggregate and 6 minutes for fine aggregate. During the oscillation process, the aggregate on the screen continuously and irregularly bounces and rolls up and down and left and right at high frequency, exposing all sides and gaps of the aggregate alternately. The atomizing nozzle continuously sprays uniform and fine solvent droplets, comprehensively wetting and coating the entire surface of the aggregate, eliminating any issues with missed spraying on the bottom surface or stacking gaps of the aggregate. After the spraying process is completed, the conveying pump stops supplying liquid, and compressed air is continuously purged through the nozzles for 1 minute to remove residual solvent and prevent clogging. The gyratory pellet mill continues to run at its original frequency for 1-3 minutes, relying on the mutual friction of the aggregates to spread out excess modified solvent on the surface of the aggregates and eliminate localized agent accumulation. This prevents the modified aggregates from sticking and clumping together from the source of the process. After the modification is completed, the discharge gate of the gyratory pellet mill is opened, and the aggregates are automatically unloaded into a sealed transfer silo.

[0061] S9 aggregate modification and constant temperature curing process

[0062] The modified and sprayed aggregates are transferred to a sealed, constant-temperature curing chamber via a sealed scraper conveyor. The curing chamber is divided into multiple layers of material placement trays, with the aggregates evenly spread on the trays. The material layer thickness is controlled to be within 8cm. The chamber door is completely sealed with sealing strips. The chamber is equipped with an electric heating temperature control system and a low-speed circulating ventilation fan. The temperature control system maintains a constant curing temperature of 40℃-65℃ inside the chamber. Low-value-added roadbed aggregates are cured at 40℃ for 6 hours, while high-end precast component aggregates are cured at 65℃ for 24 hours. The fan inside the chamber continuously circulates air at a low speed, ensuring no localized high-temperature dead zones. The small amount of solvent gas volatilized is treated by an activated carbon adsorption device on the top of the chamber before being discharged in compliance with standards. During constant temperature curing, the modified solvent components fully penetrate into the surface micropores formed after aggregate grinding. The inorganic powder and epoxy resin gradually undergo a curing reaction and firmly adhere to the inside of the aggregate pores, greatly improving the interfacial bonding force between the aggregate and cementitious materials, and solving the defects of conventional modified aggregate agents being easy to fall off and the insufficient strength of recycled building materials.

[0063] S10 Post-Standing Screening and Closed-Loop Recycling Process

[0064] After the constant temperature curing reaches the preset time, the curing chamber automatically opens, and the palletized aggregate is transferred by forklift to a double-layer linear vibrating screen. The upper screen has a mesh size of 20mm, which intercepts a small amount of large agglomerated aggregate formed during the curing process; the lower screen has a mesh size of 0.16mm, which separates the ultrafine powder that is not sufficiently modified and coated; the discharge port between the two screens produces qualified modified recycled aggregate with the required particle size and coating effect. The qualified aggregate is sent into the air-cooled conveyor channel, where it is continuously blown and dried by ambient cold air for 30 minutes to complete the shaping process. It is then transported to the finished aggregate silo for zoned storage and can be directly loaded onto trucks for use in permeable bricks, precast components, roadbed backfilling, and other projects.

[0065] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for multi-stage sorting and pretreatment of mixed solid waste from construction and its aggregate modification, characterized in that, The processing method includes the following steps: S1 raw material pre-screening and pretreatment is used to separate slag, light impurities and remove metal impurities by magnetic separation, thus completing the initial purification of raw materials; S2 multi-stage crushing, grading and sorting is used to crush and shape aggregates and, together with air classification and color classification, achieves fine grading and impurity removal to obtain multi-stage aggregate semi-finished products; S3 aggregate cleaning and activation treatment is used to clean and dry aggregates and grind away the surface inert layer to improve aggregate bonding activity. The S4 aggregate jumping device is installed to replace the adapted small screen and ensure that the aggregate remains on the screen and does not fall off. S5 aggregate is added to the gyratory pellet mill to evenly distribute activated aggregate onto the screen surface of the gyratory pellet mill. The S6 aggregate modification nozzle assembly is used to install detachable atomizing nozzles at the equipment inlet to match spray modification operations; S7 Aggregate Modification Solvent Preparation: This is used to select inorganic or organic modification solvents according to the aggregate application scenario. S8 aggregate modification treatment is used for high-frequency jumping synchronous atomization spraying of aggregates to achieve all-round coating of aggregates by modification solvents; S9 aggregate modification post-treatment is used for constant temperature static curing of aggregates to allow the modified components to fully penetrate and solidify. S10 post-sizing screening is used for secondary screening and air drying to remove unqualified particles and produce high-quality modified recycled aggregate.

2. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, The specific pre-screening and pretreatment of S1 raw materials is as follows: First, bagged debris and oversized lumps are manually removed, and then the materials are fed into a conveying and screening equipment for primary screening to separate the original slag, light organic impurities, and mixed hard solid waste. At the same time, the magnetic separation equipment adsorbs and removes metal impurities such as iron wires and steel nails from the mixed hard solid waste. The S2 multi-stage crushing, grading and sorting process is as follows: the purified mixed hard solid waste is sent to the multi-stage crushing and shaping unit, where it is crushed in sequence, then crushed in a coarse, medium and fine manner, and shaped into particles to optimize the aggregate shape and reduce the proportion of needle-shaped and flaky particles. The aggregate is then separated into three grades of recycled aggregate semi-finished products according to particle size by multi-stage screening equipment. At the same time, air classification and photoelectric color classification processes are used to remove residual light impurities and discolored inert impurities.

3. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, S3 aggregate clean activation treatment involves sending the graded aggregate semi-finished product into a cleaning and dust removal equipment to remove mud and dust, drying it to the standard moisture content, and then micro-grinding the dense inert layer on the surface of the aggregate. S4 Remove the original screen of the swing pellet mill and replace it with a custom screen with a screen hole smaller than the diameter of the aggregate particles. S5 lays the activated aggregate flat on the screen of the gyratory pellet mill; The S6 can be detachably fitted with an atomizing nozzle at the feed inlet of the oscillating pellet mill, which is compatible with the size and shape of the feed inlet. S7 selects inorganic cementitious modifiers or organic functional modifiers based on the downstream application requirements of aggregates; The S8 start-up oscillating pellet mill drives the aggregate to bounce at high frequency, and the atomizing nozzle sprays out the modified solvent. The aggregate continuously flips and changes angle, fully contacting and wetting the atomized solvent, so as to achieve uniform coating of the modified solvent on the entire surface of the aggregate.

4. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, The multi-stage crushing and shaping unit consists of a coarse jaw crusher, a medium and fine cone crusher, and a vertical impact shaping machine connected in series. The proportion of needle-shaped and flaky particles in the shaped aggregate is controlled to be below 8%. The air separator and photoelectric color sorter operate synchronously, with the air separation speed controlled at 12-18m / s and the photoelectric color sorter having high recognition accuracy.

5. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, Specific process for S3 aggregate clean activation treatment: The semi-finished aggregate is passed through a high-pressure cleaning drum to remove the mud and dust adhering to the surface. After cleaning, it is sent to a hot air drying kiln to dry until the moisture content of the aggregate is ≤2%. The dried aggregate is then sent to a drum micro-grinding unit to frictionally grind the surface layer, increasing the porosity of the aggregate surface and improving the bonding ability of the aggregate with the modified solvent.

6. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, The atomizing nozzle adopts a two-fluid high-pressure atomization structure, with atomized droplet size ranging from 20-80μm. The nozzle is detachably connected to the feed port of the oscillating pellet mill via a flange snap-fit ​​structure, and the nozzle with the corresponding flow rate specification can be replaced according to different aggregate sizes.

7. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, The modified solvent used in S7 is: The inorganic cementitious modifier is a silica fume-fly ash composite suspension, and the organic functional modifier is a 30% solids content waterborne epoxy resin emulsion. The two modifiers can be used alone or in combination in proportion, and are suitable for different aggregate application scenarios such as roadbed backfilling, permeable bricks, and prefabricated components.

8. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, The specific post-processing of S9 aggregate modification is as follows: After the modified coating is completed, the aggregate is transferred to a closed constant temperature curing chamber for static curing. The curing temperature is controlled at 40℃-65℃ and the curing time is 6h-24h. The curing chamber maintains a low-speed micro-ventilation environment to ensure that the modified components fully penetrate into the micropores inside the aggregate and solidify and adhere to the surface of the aggregate.

9. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, The specific steps for S10 post-contouring screening are as follows: After the constant temperature curing is completed, the aggregate is sent to a double-layer vibrating screen to complete the secondary screening. The upper screen retains the agglomerated aggregate, while the lower screen separates the modified uneven fine powder. The qualified aggregate is dried and shaped by ambient temperature air cooling. The unqualified particles that are agglomerated or unevenly coated are returned to the multi-stage crushing process for reprocessing.

10. The method for multi-stage sorting and pretreatment of mixed solid waste from renovation and aggregate modification according to claim 1, characterized in that, The oscillating pellet mill is set to oscillate at a frequency of 100-140 times per minute. The duration of a single atomized spray modification is 6-10 minutes. After spraying, continue oscillating for 1-3 minutes to spread out excess modifying solvent on the aggregate surface and avoid localized agent accumulation that could cause aggregate clumping.

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