A dual-channel synergistic sorting method and system for mixed-form pulp raw materials

Abstract

This invention relates to the field of papermaking waste recycling and treatment technology, and provides a dual-channel collaborative sorting method and system for mixed-form pulp raw materials. The method includes: acquiring mixed pulp raw materials; dividing the mixed pulp raw materials into a first material stream and a second material stream based on physical morphological decomposition; sequentially performing a thermal interface weakening step and a differential friction shearing step on the first material stream to reduce the interfacial bonding strength between the film layer and the paper fiber layer and to peel off the film layer; performing a dry purification step on the second material stream; and dynamically adjusting the process parameters of the thermal interface weakening step and the differential friction shearing step based on the processing feedback of the first material stream through a control unit. This invention achieves differentiated collaborative processing of raw materials with different forms, effectively solving the problems of incomplete film-paper peeling and fiber damage, significantly reducing plastic residue and ash content, and improving the quality of recycled pulp.

Description

Technical Field

[0001] This invention relates to the field of papermaking pulp technology, specifically to a dual-channel collaborative sorting method and system for mixed-form pulp raw materials. Background Technology

[0002] In the actual recycling and circulation of papermaking waste, rolls of coated paper (such as multi-layer composite food packaging, coated label rolls, etc.) and strips of processing scraps (such as book and magazine trimmings, printing slitting scraps, etc.) are often supplied to the front end of the production line in a highly mixed form, constituting the most important source of raw materials for the recycled papermaking industry.

[0003] Conventional industrial processing solutions are primarily based on the concept of unified pulping, which utilizes large-scale high-consistency pulpers to break down fiber bundles in mixed raw materials into suspension pulp suitable for subsequent processing through powerful hydraulic shearing, mechanical impact, and inter-fiber friction. This processing method demonstrates excellent process adaptability when dealing with ordinary waste paper raw materials with simple compositions and low impurity content, thanks to its extremely high throughput and mature automated control processes, laying a solid foundation for the initial large-scale industrial utilization of waste paper resources.

[0004] However, as the downstream paper industry becomes increasingly stringent in its performance requirements for high-quality recycled pulp, the inherent technical contradictions of traditional integrated pulping processes are becoming more prominent when handling mixed raw materials with highly differentiated physical forms and vastly different impurity accumulation mechanisms. Roll-formed coated raw materials have a dense structure, with fibers wrapped in a polymer film layer. Aggressive pulping can easily tear the film layer into micron-sized fragments, resulting in a high plastic residue rate. Strip-shaped scraps have a large surface area and easily adsorb silt and metal particles. Direct hydraulic pulping without dry pretreatment will increase the ash content of the pulp and exacerbate equipment wear. Roll-form strip peeling depends on a temperature field, while strip-shaped strip purification depends on vibration and airflow. A single pulping process cannot address both simultaneously and can easily cause excessive fiber damage.

[0005] Therefore, constructing a deep purification and sorting system based on morphological recognition, dual-channel diversion processing, and high synergy has become the key to breaking through the bottleneck of high-quality recycled pulp production in the field of recycled fiber preparation. Summary of the Invention

[0006] To address the problems of incomplete film-paper peeling and severe fiber damage during uniform processing of mixed pulp raw materials due to differences in morphology in existing technologies, this application proposes a dual-channel collaborative sorting method and system for mixed pulp raw materials to achieve differentiated diversion and collaborative processing based on physical morphology, thereby improving the quality of recycled pulp.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A dual-channel collaborative sorting method for mixed-form pulp raw materials includes: acquiring mixed pulp raw materials; based on physical morphological deconstruction, splitting the mixed pulp raw materials into a first material stream and a second material stream to match differentiated processing processes for different forms of raw materials; performing a thermo-mechanical coupling peeling step on the first material stream, the thermo-mechanical coupling peeling step including a thermo-mechanical interface weakening step and a differential friction shearing step, wherein the thermo-mechanical interface weakening step is used to reduce the interfacial bonding strength between the film layer and the paper base fiber layer, and the differential friction shearing step is used to apply tangential shear stress after the interfacial bonding strength is reduced, so as to collaboratively drive the film layer to undergo overall plastic slip peeling from the paper base fiber layer; and performing a dry purification step on the second material stream.

[0009] Optionally, the step of dividing the mixed pulp raw material into a first material flow and a second material flow based on physical morphological characteristics includes: dividing the mixed pulp raw material into a first material flow for rolls or large blocks and a second material flow for strips or fragments through a geometric size screening mechanism and a gravity sensing mechanism.

[0010] Optionally, the thermal interface weakening step includes: supplying energy to the adhesive layer on the surface of the coating material in a controlled hot air environment to induce a glass transition in the adhesive layer.

[0011] Optionally, the temperature of the controlled hot air environment is controlled between 60°C and 80°C, and the residence time of the coating material in the controlled hot air environment is not less than 10 seconds.

[0012] Optionally, the differential friction shearing sequence includes: applying tangential shear stress to both sides of the raw material through a differential friction mechanism to drive the film layer to undergo overall plastic slip peeling.

[0013] Optionally, the differential friction mechanism includes a first friction roller and a second friction roller, the differential speed ratio between the first friction roller and the second friction roller is controlled between 1.3:1 and 1.8:1, and the normal compressive stress applied to the surface of the raw material by the differential friction mechanism is controlled between 0.5MPa and 2.0MPa; wherein, the generated shear stress τ follows the following relationship: τ=μ·Δv / h·σ, where μ is the dynamic friction coefficient between the film and paper, Δv is the difference in linear velocity between the first friction roller and the second friction roller, h is the thickness of the raw material under pressure, and σ is the normal compressive stress.

[0014] Optionally, the dry purification process includes: a three-dimensional high-frequency vibration removal process, a magnetic coupling collection process, and a cyclone gas-solid separation process; wherein, the three-dimensional high-frequency vibration removal process is used to precipitate inorganic impurities on the surface of the strip fibers, the magnetic coupling collection process is used to collect the mixed fine magnetic metal foreign matter, and the cyclone gas-solid separation process is used to achieve the physical separation of paper strip fibers and light ash particles.

[0015] Optionally, it further includes: dynamically adjusting the process parameters of the thermal interface weakening step sequence and the differential friction shearing step sequence based on the processing feedback of the first material flow through the control unit; wherein, the dynamic adjustment includes: acquiring a surface image of the paper substrate after the first material flow has been processed; analyzing the percentage of residual film area in the surface image; and adjusting the temperature parameter of the thermal interface weakening step sequence or the differential speed ratio parameter of the differential friction shearing step sequence in response to the percentage of residual film area exceeding a preset threshold.

[0016] Furthermore, the present invention also provides a sorting system for mixed pulp raw materials, comprising: a feeding and diversion device for receiving mixed pulp raw materials and diverting them into a first processing channel and a second processing channel according to their physical properties, so as to match differentiated processing processes for raw materials of different forms; a first processing subsystem disposed in the first processing channel, comprising a thermal interface weakening unit and a differential friction shearing unit, wherein the thermal interface weakening unit is used to reduce the interfacial bonding strength between the film layer and the paper base fiber layer, and the differential friction shearing unit is used to apply tangential shear stress after the interfacial bonding strength is reduced, so as to synergistically drive the film layer to undergo overall plastic slip peeling from the paper base fiber layer; and a second processing subsystem disposed in the second processing channel, comprising a dry purification unit for dry purification treatment of the material.

[0017] Optionally, the system further includes a control unit, which is signal-connected to the feeding and diversion device, the first processing subsystem, and the second processing subsystem, for dynamically adjusting the process parameters of the thermal interface weakening unit and the differential friction shearing unit based on the processing feedback of the first processing subsystem.

[0018] Optionally, the feeding and diversion device includes an electromagnetic feeding hopper and a roller-type length grading screen, wherein a load sensor is installed at the bottom of the electromagnetic feeding hopper; the roller-type length grading screen is composed of several sets of parallel-arranged irregular-shaped rollers, each of which is connected to an independent variable frequency motor; the thermal interface weakening unit adopts a circulating air duct structure, and its insulation layer uses materials with a thermal conductivity lower than that of the standard. The nano-aerogel composite material; the friction roller surface of the differential friction shear unit is covered with a height of to The diamond-shaped protrusion structure is made of polyurethane coating with a Shore hardness between A85 and A95, and the differential friction shear unit is equipped with a hydraulic system to control the radial pressure between the two rollers.

[0019] Beneficial effects:

[0020] This invention employs a diversion strategy based on the deconstruction of physical morphology, separating mixed raw materials into two channels for processing: roll material and strip material. This avoids the mutual interference problems caused by differences in raw material morphology in traditional uniform fragmentation processes. Specifically for roll-coated raw materials, a synergistic peeling mechanism combining thermal interface weakening and differential friction shearing is used. Controlled thermal energy induces a glass transition in the adhesive layer, significantly reducing the bonding strength at the film-paper interface. Combined with a specific differential speed ratio and normal compressive stress to apply tangential shear stress, the film layer can be peeled from the paper fiber layer through overall plastic slippage, rather than being forcefully broken into microplastic particles. This peeling method not only reduces the plastic residue rate in the finished pulp to a minimum... The following methods significantly improve the purity of recycled fibers and effectively prevent damage to the physical length of fibers caused by strong mechanical shearing, resulting in a significant improvement in the breaking length and folding endurance of the recycled pulp. Simultaneously, a dry purification process is used for strip-shaped raw materials, removing impurities such as silt and metal beforehand without consuming water resources, thus reducing the load on subsequent water treatment and the risk of equipment wear. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of a dual-channel collaborative sorting system for mixed pulp raw materials according to the present invention.

[0023] Figure 2 This is a schematic diagram of the process of the present invention.

[0024] The attached figures are labeled as follows:

[0025] 1. Feeding and diversion device; 2. Electromagnetic feeder hopper; 3. Load sensor; 4. Roller-type length grading screen; 5. Irregularly shaped shaft roller; 6. Coiling channel; 7. Strip channel; 8. Pre-unfolding roller group; 9. Hot air tunnel; 10. Heating element; 11. Differential friction mechanism; 12. First friction roller; 13. Second friction roller; 14. Online vision inspection module; 15. Three-dimensional vibrating screen; 16. Permanent magnet drum; 17. Cyclone separator; 18. Central coordination and control unit. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0027] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] Example 1

[0029] This embodiment provides a dual-channel collaborative sorting method for mixed-form pulp raw materials. This method discretizes and sorts the mixed raw materials based on the deconstruction of their physical morphological properties. For example... Figure 1 As shown, the method includes the following steps:

[0030] Step S100: Obtain mixed pulp raw materials.

[0031] Specifically, mixed pulp raw materials typically include rolls of coated paper (such as multi-layer composite food packaging and coated label rolls) and strips of processing scraps (such as book trimmings and printing slitting scraps). These raw materials often exist in a highly mixed form during the recycling process.

[0032] Step S200: Based on the physical morphological properties, the mixed pulp raw materials are divided into a first material flow and a second material flow.

[0033] The physical morphology analysis not only involves screening the geometric dimensions of raw materials but also includes a comprehensive assessment of their physical state. Specifically, physical state includes characteristics such as the curvature, density, and presence of a film coating. This analysis divides the raw materials into a first flow for rolled or bulk materials and a second flow for strip-shaped or fragmented materials. This diversion strategy avoids the mutual interference problems caused by uniformly breaking down mixed raw materials in traditional processes. For example, rolled materials are difficult to break down due to film coating, while strip-shaped materials easily absorb impurities due to their large surface area, thus laying the foundation for subsequent differentiated processing.

[0034] Step S300: Perform a thermal-mechanical coupling stripping sequence on the first material flow, the thermal-mechanical coupling stripping sequence including a thermal interface weakening sequence and a differential friction shearing sequence.

[0035] The thermal interface weakening step is used to reduce the interfacial bonding strength between the film layer and the paper-based fiber layer. Specifically, this step uses controlled heat energy applied to the coating material to induce a physical state transformation in the adhesive layer between the film layer and the paper-based fiber layer, thereby significantly reducing the interfacial adhesion and creating conditions for subsequent peeling. The differential friction shearing step is used to apply tangential shear stress after the interfacial bonding strength is reduced, so as to synergistically drive the film layer to peel off from the paper-based fiber layer through overall plastic slip. Specifically, this step uses a differential friction mechanism 11 to apply frictional forces in opposite directions or at different speeds on both sides of the material to form tangential shear stress. There is a synergistic relationship between the thermal interface weakening step and the differential friction shearing step: the former loosens the bond between the film layer and the paper-based fiber layer by lowering the peeling threshold; the latter provides precise peeling force, allowing the film layer to peel off from the paper-based fiber layer through overall plastic slip, rather than being forcefully broken into microplastic particles. This synergistic effect not only improves the thoroughness of film-paper separation, but also effectively protects the physical length of the fibers.

[0036] Step S400: Perform a dry purification procedure on the second material flow.

[0037] Specifically, the dry purification process includes three-dimensional high-frequency vibration removal, magnetic coupling capture, and cyclone gas-solid separation to remove silt, metal particles, and light ash adsorbed on the surface of the strip-shaped raw materials. This step achieves pre-purification of the strip-shaped raw materials without consuming water resources, reducing the load on subsequent water treatment systems.

[0038] In step S500, the process parameters of the thermal interface weakening step sequence and the differential friction shearing step sequence are dynamically adjusted by the control unit 18 based on the processing feedback of the first material flow.

[0039] Specifically, the control unit 18 collects real-time data on the peeling effect of the membrane paper after the first material flow has passed through the treatment, such as obtaining the percentage of residual membrane area through visual inspection. When the peeling effect does not meet the preset standard, the control unit 18 automatically adjusts the temperature parameters of the thermal interface weakening step or the differential speed ratio parameters of the differential friction shear step to adapt to the differences in the bonding performance of different batches of raw materials, ensuring the stability and efficiency of the system operation.

[0040] Through the above solution, this embodiment realizes a targeted processing strategy based on morphological differences, which solves the problems of incomplete film-paper peeling, severe fiber damage and excessive ash content caused by the uniform processing of mixed raw materials in the prior art, and significantly improves the quality of recycled pulp.

[0041] Example 2

[0042] Based on the above embodiments, this embodiment provides a preferred physical diversion path for the specific implementation of dividing the mixed pulp raw materials into a first material flow and a second material flow based on physical morphological deconstruction in step S200.

[0043] Specifically, this diversion process is achieved through the combined action of a geometric size screening mechanism and a gravity sensing mechanism. For example... Figure 2 As shown, the mixed pulp raw materials first enter the feeding and diversion device 1. The gravity sensing mechanism (such as the load sensor 3 set at the bottom of the feeding hopper) monitors the weight change rate of the raw materials in real time. This data reflects the density and instantaneous flow rate of the feed flow. By adjusting the vibration amplitude of the feeding device through feedback, it is ensured that the raw materials can be evenly spread in a single-layer discrete state, avoiding screening dead corners caused by accumulation, and creating conditions for subsequent geometric size screening.

[0044] Subsequently, the raw materials enter a geometric size screening mechanism. In this embodiment, the mechanism preferably employs a roller-type length grading screen 4, which uses the gap between the rollers to physically grade the raw materials. Rolled or bulk raw materials (such as laminated packaging rolls) typically have larger geometric dimensions and specific curling shapes, while strip-shaped or fragmented raw materials (such as printing trimmings) are smaller in size and loose in shape. Based on statistical analysis of the geometric characteristics of a large amount of recycled pulp raw materials, this embodiment sets the radial gap between the rollers between 80mm and 120mm. This numerical range is based on the precise definition of morphological differences: when the characteristic size of rolled materials is typically greater than 80mm, it can be carried by the rollers and conveyed forward to the rolling channel 6, forming the first material flow; while the characteristic size of strip-shaped fragments is typically less than 120mm, and under the disturbance of gravity and roller rotation, they easily pass through the roller gap and fall into the strip channel 7, forming the second material flow.

[0045] If the gap is less than 80mm, some rolls of material with a larger unfolded width may be misjudged as strips and fall into the second material flow, causing overload in the subsequent dry purification process and incomplete membrane-paper separation. If the gap is greater than 120mm, some slender strips may not be able to effectively pass through and mix into the first material flow, increasing the energy consumption burden of the subsequent thermal peeling process. Through the combination of the above-mentioned geometric size screening and gravity sensing, the system can efficiently and accurately divert the mixed raw materials into a first material flow for rolls or large pieces of raw materials and a second material flow for strips or fragments of raw materials, with a diversion accuracy that can be consistently maintained above 98%.

[0046] Example 3

[0047] Based on the above embodiments, this embodiment provides a preferred thermal energy replenishment scheme for the specific implementation of the thermal interface weakening step sequence in step S300.

[0048] Specifically, the thermal interface weakening process involves supplying energy to the adhesive layer on the surface of the coating material in a controlled hot air environment, inducing a glass transition in the adhesive layer. The first material flow passes through the pre-expanding roller group 8 and then enters the hot air tunnel 9, which creates a controlled hot air environment with a uniform temperature field. The coating material is typically composed of a paper-based fiber layer and a plastic film layer (such as PE or PET film), bonded together by an adhesive layer (such as ethylene-vinyl acetate copolymer EVA hot melt adhesive or pressure-sensitive adhesive). At room temperature, this adhesive layer is in a glassy or highly elastic state, with restricted molecular chain movement and high interfacial bonding strength. Direct mechanical peeling can easily lead to fiber breakage or film tearing. In this embodiment, heat energy is supplied to the adhesive layer through a controlled hot air environment. When the adhesive layer absorbs energy, its molecular chain movement intensifies. In particular, when the temperature reaches a certain range, the adhesive layer will undergo a glass transition, changing from a hard glassy state to a soft, highly elastic state or even a viscous flow state. At this time, the intermolecular interaction forces are greatly weakened, and the interfacial bonding strength between the film layer and the paper-based fiber layer is significantly reduced, which facilitates subsequent peeling.

[0049] Furthermore, to ensure the adhesive layer undergoes a sufficient glass transition without damaging the paper fibers, the temperature of the controlled hot air environment is maintained between 60°C and 80°C, and the residence time of the coating material in the controlled hot air environment is no less than 10 seconds. This parameter range is based on extensive experimental verification and material thermophysical property analysis. If the hot air temperature is below 60°C, the heat energy absorbed by the adhesive layer is insufficient to overcome the energy barrier of molecular chain segment movement, resulting in an incomplete glass transition and a limited decrease in interfacial bonding strength. This leads to the subsequent peeling process requiring greater shear force, which can easily cause fiber damage and incomplete peeling. Conversely, if the hot air temperature is above 80°C, although the softening effect of the adhesive layer is more obvious, the excessively high temperature will cause the moisture in the paper fibers to evaporate rapidly, making the fibers brittle or even thermally degraded. At the same time, the film layer may undergo uncontrollable deformation or stick to the equipment due to excessive softening, which will increase the difficulty of separation. Therefore, 60°C to 80°C is the optimal temperature to achieve "interfacial weakening without damaging the substrate". Meanwhile, a dwell time of at least 10 seconds is a necessary condition for energy accumulation. Heat needs time to conduct from the film surface to the internal adhesive layer. If the dwell time is too short, heat cannot penetrate to the interface layer, and only the surface film is heated, failing to achieve the overall interface weakening effect. This embodiment ensures that the adhesive layer of each coated material reaches its optimal pre-peeling state by precisely controlling the coupling relationship between temperature and time.

[0050] Example 4

[0051] Based on the above embodiments, the specific implementation method of the differential friction shearing step sequence in step S300 is as follows.

[0052] Specifically, the differential friction shearing sequence includes applying tangential shear stress to both sides of the raw material via a differential friction mechanism 11, driving the film layer to undergo overall plastic slip peeling. The coated raw material, after being weakened by thermal interface, enters the differential friction mechanism 11. The raw material passes between two rollers, which rotate at different linear velocities. The "overall plastic slip peeling" described in this embodiment refers to the film layer not breaking or fragmenting into tiny pieces when subjected to shear force, but maintaining a relatively intact sheet-like shape, sliding relative to each other and detaching along the interface between the film layer and the paper-based fiber layer. This embodiment achieves "overall peeling" of the film layer through precise control of shear stress, eliminating the generation of microplastics at the source.

[0053] Furthermore, to achieve the aforementioned "overall plastic slip peeling," precise control of the shear stress is necessary. In this embodiment, the differential friction mechanism 11 includes a first friction roller 12 and a second friction roller 13. The differential speed ratio between the first friction roller 12 and the second friction roller 13 is controlled between 1.3:1 and 1.8:1, and the normal compressive stress applied to the raw material surface by the differential friction mechanism 11 is controlled between 0.5 MPa and 2.0 MPa. The generated shear stress τ follows the following relationship: τ = μ·Δv / h·σ, where μ is the dynamic friction coefficient between the film and paper, Δv is the difference in linear velocity between the first friction roller 12 and the second friction roller 13, h is the thickness of the raw material under pressure, and σ is the normal compressive stress.

[0054] To increase the dynamic friction coefficient μ between the film and paper, thereby generating greater shear stress under the same compressive stress and differential speed conditions, the friction roller surface in this embodiment is covered with a diamond-shaped protrusion structure with a height of 3mm to 5mm, and this diamond-shaped protrusion structure is coated with a polyurethane coating with a Shore hardness between A85 and A95. This design, on the one hand, utilizes the diamond-shaped protrusions to increase the roughness of the roller surface, significantly improving the friction coefficient μ and ensuring the effective transmission of shear stress; on the other hand, the polyurethane coating has suitable elastic hardness, which can provide sufficient gripping force while avoiding rigid damage to the fibers caused by the hard metal roller surface. In actual operation, the first friction roller 12 and the second friction roller 13 form a strong clamping force on the raw material. Under the action of differential rotation, the front and back sides of the raw material are subjected to frictional forces in opposite directions, thereby forming huge shear stress at the film-paper interface, driving the film layer to slide and peel off from the paper base as a whole, like "taking off clothes," achieving efficient and clean film-paper separation.

[0055] Example 5

[0056] Based on the above embodiments, the specific implementation method of performing dry purification steps on the second material flow in step S400 is as follows.

[0057] Specifically, the dry purification process includes a three-dimensional high-frequency vibration removal step, a magnetic coupling collection step, and a cyclone gas-solid separation step. The second material stream (i.e., strip-shaped or fragmented raw materials) first enters the three-dimensional high-frequency vibration removal step. During the initial processing and transfer of strip-shaped scraps, their surfaces easily adsorb inorganic impurities such as mud, sand, and mineral dust. In this embodiment, the three-dimensional vibrating screen 15 generates multi-directional synthetic excitation force, causing the material to advance in a spiral jumping manner on the screen surface. This high-frequency vibration can destroy the van der Waals forces and electrostatic adsorption forces between impurity particles and the fiber surface, causing smaller particles of mud, sand, and inorganic mineral dust to precipitate from the fiber surface and pass through the screen holes into the slag collection tank. This process mainly utilizes the physical principle of vibration energy transfer, achieving efficient removal of surface impurities without water washing.

[0058] Subsequently, the material enters the magnetic coupling collection process. This process utilizes a permanent magnet drum 16 to generate a high-intensity gradient magnetic field to collect fine magnetic metallic foreign objects, such as iron nails and iron filings, embedded in the strip fibers. Specifically, when the material flows over the drum surface, the magnetic foreign objects are subjected to a magnetic force pointing towards the center of the drum. The magnitude of this magnetic force is proportional to the product of the magnetic induction intensity B and the magnetic field gradient dB / dx.

[0059] Finally, the material enters the cyclone air-solid separation process, where the centrifugal force field inside the cyclone separator 17 achieves the physical separation of paper fibers and light ash particles. Specifically, after the material enters the cyclone separator 17 with the airflow, it undergoes high-speed rotation. According to the centrifugal force formula Fc=m·vt² / r, the centrifugal force Fc on the particles is directly proportional to the square of their mass m and tangential velocity vt, and inversely proportional to the radius of rotation r. Since the density and mass of ash particles are much greater than those of paper fibers, under the action of centrifugal force, the ash particles are thrown against the wall of the separator and fall down the wall surface, exiting from the ash discharge port; while the lighter paper fibers are discharged from the central settling tank with the rising airflow. This process effectively removes the light ash mixed in with the raw materials, further reducing the ash content of the pulp.

[0060] This embodiment achieves deep impurity removal from strip-shaped raw materials through the aforementioned three-stage dry purification process without consuming water resources. On the one hand, it avoids the dissolution of water-soluble impurities such as mud and salt into the pulp water, which is present in traditional water washing processes, significantly reducing the load and cost of subsequent water treatment systems. On the other hand, dry treatment avoids excessive swelling and rubbing of fibers in water, maximizing the protection of the physical length of the fibers and laying the foundation for the subsequent preparation of high-strength recycled pulp. In addition, to prevent the strip-shaped material after dry purification from being over-dried and affecting subsequent pulping performance, the system can optionally be equipped with an online moisture compensation device at the discharge port of the cyclone separator 17. This device uses atomized spraying to quantitatively humidify the purified material, ensuring that its moisture content meets the process requirements.

[0061] Example 6

[0062] Based on the above embodiments, the specific implementation method of dynamically adjusting the process parameters based on the processing feedback of the first material flow in step S500 is as follows.

[0063] Specifically, this includes acquiring images of the surface of the paper substrate after the first material has been processed. For example... Figure 1 An online visual inspection module 14 is installed at the exit end of the differential friction shearing step. This module typically includes a high-resolution industrial camera and a matching uniform light source system. As the paper substrate after peeling passes through this area, the industrial camera captures image information of its surface in real time. This process requires no manual intervention and can continuously monitor the peeling quality on the production line around the clock.

[0064] Subsequently, the system analyzes the percentage of residual film area in the surface image. The control unit 18 incorporates an image processing algorithm, preferably employing a convolutional neural network (CNN) algorithm for feature extraction and segmentation of the captured image. The algorithm automatically identifies residual film areas in the image and calculates the percentage of their area relative to the total area of ​​the paper substrate; this percentage is a key quantitative indicator for measuring the peeling effect. Because different batches of recycled raw materials have complex origins, their coating processes, adhesive types, and aging degrees vary, leading to fluctuations in peeling effects under the same process parameters. Therefore, this real-time quantitative analysis is fundamental to ensuring the system's adaptability.

[0065] Furthermore, in response to the residual film area percentage exceeding a preset threshold, the system adjusts the temperature parameter of the thermal interface weakening step or the differential speed ratio parameter of the differential friction shearing step. In this embodiment, the preset threshold is set to 0.5%. When the residual film area percentage detected by visual inspection exceeds 0.5%, it indicates that the current peeling effect has not met the standard and the interfacial adhesion has not been sufficiently overcome. At this time, the control unit 18 will automatically trigger a closed-loop adjustment command. The adjustment logic follows one of the following two paths or a combination thereof:

[0066] Path 1: Increase the temperature parameters of the thermal interface weakening step. Specifically, the control unit 18 increases the set temperature of the hot air tunnel 9 in 5°C increments. The increased temperature allows more heat energy to be input into the adhesive layer, promoting a more complete glass transition and further reducing the interfacial bonding strength, thus making it easier to peel off in the subsequent shearing step.

[0067] Path two involves increasing the differential ratio parameter of the differential friction shearing step sequence. Specifically, the control unit 18 increases the differential ratio by 5%. Increasing the differential ratio means that the linear velocity difference Δv between the first friction roller 12 and the second friction roller 13 increases. According to the shear stress formula τ=μ·Δv / h·σ, this directly leads to an increase in the shear stress τ applied to the film-paper interface, thereby more effectively overcoming the residual adhesive force.

[0068] The system will continuously monitor the adjusted visual feedback until the percentage of residual membrane area returns to the acceptable range. This closed-loop control mechanism based on visual feedback gives the system intelligent and adaptive capabilities to cope with fluctuations in raw material properties, ensuring the continuous stability of the sorting process and high-quality output.

[0069] Example 7

[0070] This embodiment provides a sorting system for mixed-form pulp raw materials. This system serves as the physical carrier for implementing the sorting methods described in Embodiments 1 to 6. For example... Figure 1 As shown, the system includes a feeding and diversion device 1, a first processing subsystem, a second processing subsystem, and a control unit 18.

[0071] The feeding and diversion device 1 receives the mixed pulp raw materials and divides them into a first processing channel and a second processing channel according to their physical properties. Specifically, the feeding and diversion device 1 integrates a geometric screening mechanism and a gravity sensing mechanism. In actual operation, the mixed pulp raw materials enter the feeding and diversion device 1 via a conveyor belt or grab bucket, and the roller-type length grading screen 4 inside the device performs physical grading according to the geometric characteristics of the raw materials. The feeding and diversion device 1 not only diverts the flow but also balances the flow rate and disperses the material, ensuring the stability of the feed to the subsequent processing channels. The outlet of this device is physically connected to the inlet of the first processing subsystem and the inlet of the second processing subsystem through conveying equipment (such as a belt conveyor or chute), thereby constructing a dual-channel parallel processing architecture.

[0072] The first processing subsystem, located within the first processing channel, includes a thermal interface weakening unit and a differential friction shearing unit. The thermal interface weakening unit is a hot air tunnel 9 or a heating oven, internally equipped with heating elements 10, air ducts, and insulation structures for controlled heating of the material. The differential friction shearing unit is located downstream of the thermal interface weakening unit and consists of two or more relatively rotating friction rollers, equipped with a hydraulic pressurization system. Within the first processing subsystem, the material undergoes two consecutive processes: thermal softening and mechanical peeling, achieving efficient separation of the film and paper. At the end of this subsystem, a film collection device and a paper base output device are also provided to collect the peeled plastic film and paper base fiber layer, respectively.

[0073] The second processing subsystem, located within the second processing channel, includes a dry purification unit for dry purification of the materials. The dry purification unit is a multi-stage series of impurity removal devices, such as a three-dimensional vibrating screen 15, a permanent magnet drum 16, and a cyclone separator 17 connected in sequence. This subsystem does not involve washing or pulping processes; it relies entirely on physical fields such as mechanical vibration, magnetic force, and centrifugal force to remove impurities. This dry architecture not only simplifies the system structure and avoids wastewater treatment, but also effectively protects the physical length of the strip fibers.

[0074] The control unit 18 is connected to the feeding and diversion device 1, the first processing subsystem, and the second processing subsystem. Based on the processing feedback from the first processing subsystem, it dynamically adjusts the process parameters of the thermal interface weakening unit and the differential friction shearing unit. Specifically, the control unit 18 uses a programmable logic controller (PLC) or an industrial computer (IPC) as its hardware core. The control unit 18 establishes communication connections with the actuators (such as frequency converters, heaters, and hydraulic valves) and sensors (such as temperature sensors, vision inspection modules, and pressure sensors) of each subsystem via a fieldbus (such as Profinet or EtherCAT). During operation, the control unit 18 collects real-time visual inspection data from the end of the first processing subsystem, analyzes the film peeling effect, and automatically adjusts key parameters such as hot air temperature and friction roller differential ratio according to a preset control algorithm (such as PID control or fuzzy control). Simultaneously, the control unit 18 also monitors the flow signal of the feeding and diversion device 1, coordinates the load balance of the two channels, and ensures stable operation of the system under optimal conditions.

[0075] Through the above architecture, this embodiment constructs a modular and automated sorting system. Each subsystem has a clearly defined function, is relatively independent yet works in concert, achieving not only precise diversion and differentiated processing of mixed-form pulp raw materials, but also ensuring the stability and consistency of the processing effect through closed-loop control logic. This system architecture has good scalability and adaptability, and can be flexibly configured according to the site conditions and capacity requirements of different paper mills.

[0076] Example 8

[0077] Based on the above embodiments, the specific structural details of each key device in the sorting system are as follows.

[0078] Specifically, the feeding and diversion device 1 includes an electromagnetic feed hopper 2 and a roller-type length grading screen 4, with a load sensor 3 installed at the bottom of the electromagnetic feed hopper 2. For example... Figure 2As shown, the electromagnetic feed hopper 2 serves as the system's inlet. Its bottom load sensor 3 can detect real-time changes in the weight of the accumulated material and feed the signal back to the control unit 18. This allows for the adjustment of the electromagnetic vibration amplitude to balance the feed flow rate, preventing excessive material buildup on the subsequent grading screen and ensuring accurate separation. The roller-type length grading screen 4 consists of several sets of parallel-arranged irregular-shaped rollers 5, each connected to an independent variable-frequency motor. Traditional round rollers are prone to material slippage or accumulation during transport, resulting in low separation efficiency. The irregular-shaped rollers 5 used in this embodiment preferably have a non-circular cross-section (such as a plum blossom or elliptical cross-section). This structure generates periodic undulating oscillations during rotation, continuously throwing and loosening the material, effectively preventing flat, rolled materials from getting stuck in the gaps and accidentally entering the strip channel 7, while also increasing the probability of strip materials passing through the gaps. Each roller is connected to an independent variable-frequency motor, allowing the control unit 18 to differentiate the rotation speed of each roller based on the material buildup thickness in different areas of the screen surface. For example, increasing the rotation speed at the beginning of the screen to quickly spread the material, and decreasing the rotation speed at the end to extend the screening time for strip materials, thereby stabilizing the diversion accuracy at a high level.

[0079] Example 9

[0080] To verify the practical application effect of the sorting method and system provided by this invention, this embodiment selects a recycled pulp production line as an application scenario for detailed description. In this application scenario, the mixed pulp raw materials processed include 40% by weight of coated roll material (mainly multi-layer composite food packaging roll material) and 60% by weight of strip scrap material (mainly book trimming and printing slitting waste). The system is configured according to the architecture described in the previous embodiment, and the key process parameters are set as follows during operation: the hot air temperature in the thermal interface weakening step is set to 70°C, and the residence time of the coated raw material in the hot air tunnel 9 is controlled to 12 seconds; the differential speed ratio in the differential friction shearing step is set to 1.5:1, and the normal compressive stress is set to 1.2 MPa.

[0081] Under the above operating conditions, the system runs continuously and collects output data. To intuitively demonstrate the technical advantages of this invention, the process scheme of this embodiment is used as the experimental group, and the traditional unified crushing and post-hydraulic slag removal process is used as the comparative example. The sorting effects of the two are compared and analyzed. The comparison data are shown in Table 1 below:

[0082] Table 1 Comparison of sorting effects between embodiments of the present invention and traditional processes.

[0083]

[0084] Parameter boundary verification experiment:

[0085] To verify the necessity and rationality of the key parameter ranges of this invention, this embodiment further conducted parameter boundary comparison experiments. Specifically, for the temperature parameters of the thermal interface weakening step sequence and the differential speed ratio parameters of the differential speed friction shear step sequence, comparison groups exceeding the limits defined by this invention were set up respectively. The experimental results are shown in Tables 2 and 3:

[0086] Table 2. Experimental Results of Hot Air Temperature Parameter Boundary Comparison

[0087]

[0088] As can be seen from Table 2, when the hot air temperature is lower than At that time (comparison groups A1 and A2), the glass transition of the adhesive layer was insufficient, and the decrease in interfacial bonding strength was limited, resulting in incomplete peeling of the film and paper and a significant increase in plastic residue. to This is far superior to the embodiments of the present invention. Even if the stay is extended to (Comparison group A2), still could not achieve the desired peeling effect. Conversely, when the hot air temperature was higher than... At the same time (comparison groups B1 and B2), although the softening effect of the adhesive layer was more obvious, the excessively high temperature caused the moisture in the paper base fiber to evaporate rapidly, making the fiber brittle and even causing thermal degradation. The average fiber length decreased from [previous value]. Descending to to The decline reached to This severely affects the strength properties of the regenerated pulp. Simultaneously, the membrane layer undergoes uncontrollable deformation or adheres to the equipment due to excessive softening, further increasing the difficulty of separation. This fully demonstrates that the present invention effectively controls the hot air temperature within... to The necessity and rationality of this relationship.

[0089] Table 3. Experimental Results of Differential Ratio Parameter Boundary Comparison

[0090]

[0091] As can be seen from Table 3, when the differential ratio is lower than At that time (comparison groups C1 and C2), the linear velocity difference Δv was insufficient, resulting in insufficient shear stress τ. This made it impossible to overcome the weakened interfacial adhesion strength of the film and paper after heat treatment, leading to low peeling efficiency and a high plastic residue rate. to Even if the normal compressive stress is increased to (Comparison group C2) still could not effectively improve the peeling effect and required multiple cycles, significantly reducing production efficiency. Conversely, when the differential speed ratio was higher than... At time (comparison groups D1 and D2), the shearing action was too intense, and the shear stress τ exceeded the breaking strength of the paper-based fiber, causing the fiber to break. The average fiber length decreased from... Descending to to The decline reached to Simultaneously, the membrane layer tore and broke under intense shearing, generating a large number of microplastic particles, and the plastic residue rate actually increased. to Furthermore, the membrane-paper separation state changes from "whole peeling" to "fragmented separation," thus losing the core technological advantage of this invention. This fully demonstrates that this invention controls the differential speed ratio at... to The necessity and rationality of this relationship.

[0092] It is worth noting that the technical effect of this invention is not a simple superposition of a single parameter, but rather the result of the synergistic effect of three parameters: temperature, differential speed ratio, and normal compressive stress. As shown in Table 4, only when all three parameters are within the preferred range defined by this invention can the dual optimization effect of "significantly reduced plastic residue rate" and "significantly increased fiber length" be achieved.

[0093] Table 4. Experimental Results Comparing the Synergistic Effects of Parameters

[0094]

[0095] As clearly shown in Table 4, only when the three parameters—temperature, differential speed ratio, and normal compressive stress—are simultaneously within the preferred range defined by this invention can the "window condition" of shear stress τ precisely falling between the "interfacial adhesion strength of the film-paper interface after thermal weakening" and the "fracture strength of the paper-based fibers" be achieved, thereby realizing the overall plastic slip peeling of the film layer. Optimization of a single parameter cannot achieve this effect, fully demonstrating the synergistic and non-obvious nature of the "thermal-mechanical coupling peeling" mechanism of this invention.

[0096] As can be seen from the data in Table 1, the embodiments of the present invention demonstrate significant advantages in several key indicators. Specifically, regarding the plastic residue rate, the experimental group reduced it to [a lower percentage]. The following is only a comparative example. The mechanism behind this significant reduction lies in the fact that this invention induces a glass transition in the adhesive layer and applies precise shear stress through the synergistic effect of thermal interface weakening and differential frictional shearing. This allows the film layer to peel off from the paper-based fiber layer via "overall plastic slip," rather than tearing the film layer into micron-sized microplastic particles as in traditional high-intensity disintegration processes. This overall peeling method eliminates difficult-to-remove microplastic residues at the source, significantly improving the purity of the recycled fibers.

[0097] Regarding fiber length retention, the experimental group achieved 96.5%, an improvement of over 18 percentage points compared to the control group. This is because the present invention employs gentle thermal weakening and shear peeling for roll materials, avoiding the cutting and damage to the fiber structure caused by the strong mechanical impact of high-consistency pulpers in traditional processes. Simultaneously, the dry purification process used for strip materials avoids excessive rubbing and swelling breakage of fibers during hydraulic conveying, thereby maximizing the protection of fiber physical length. This is crucial for improving the breaking length and folding endurance of recycled pulp.

[0098] Regarding ash content, the experimental group consistently maintained it below 0.5%. This is attributed to the three-stage dry purification process undertaken by the second material stream (strip material): three-dimensional high-frequency vibration removal, magnetic coupling capture, and cyclone air-solid separation. This dry treatment strategy effectively removes silt, metal, and dust adsorbed on the surface of the strip material, and avoids the problem of water-soluble impurities dissolving into the slurry water during the washing process, thus significantly reducing the load on the subsequent water treatment system. Furthermore, the differentiated diversion treatment strategy avoids energy waste when processing rolled and strip materials in the same way, resulting in a reduction of approximately 34% in energy consumption per ton of material, demonstrating excellent energy-saving and consumption-reducing effects. In summary, this invention demonstrates superior sorting performance and economic benefits in practical applications.

[0099] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. Those skilled in the art will understand that the selection of materials for various components, the adjustment of structural dimensions, and the parameters of the control algorithm, without departing from the core design concept of the present invention, are all well-known technical means in this field.

Claims

1. A dual-channel collaborative sorting method for mixed-form pulp raw materials, characterized in that, include: Obtain mixed pulp raw materials; Based on the physical morphological properties, the mixed pulp raw material is divided into a first material stream and a second material stream to match differentiated processing processes for raw materials of different morphological properties. A thermo-mechanical coupling peeling sequence is performed on the first material flow. The thermo-mechanical coupling peeling sequence includes a thermo-mechanical interface weakening sequence and a differential friction shearing sequence. The thermo-mechanical interface weakening sequence is used to reduce the interfacial bonding strength between the film layer and the paper-based fiber layer. The differential friction shearing sequence is used to apply tangential shear stress after the interfacial bonding strength is reduced, so as to synergistically drive the film layer to undergo overall plastic slip peeling from the paper-based fiber layer. A dry purification step is performed on the second material flow.

2. The sorting method according to claim 1, characterized in that, The method of dividing the mixed pulp raw material into a first material stream and a second material stream based on physical morphological deconstruction includes: Through a geometric size screening mechanism and a gravity sensing mechanism, the mixed pulp raw material is divided into a first material flow for rolls or large blocks of raw material and a second material flow for strips or shredded raw material.

3. The sorting method according to claim 1, characterized in that, The thermal interface weakening steps include: Energy is supplied to the adhesive layer on the surface of the coating material in a controlled hot air environment to induce a glass transition in the adhesive layer.

4. The sorting method according to claim 3, characterized in that, The temperature of the controlled hot air environment is controlled between 60°C and 80°C, and the residence time of the coating material in the controlled hot air environment is not less than 10 seconds.

5. The sorting method according to claim 1, characterized in that, The differential friction shearing sequence includes: By applying tangential shear stress to both sides of the raw material through a differential friction mechanism, the film layer is driven to undergo overall plastic slippage and peeling.

6. The sorting method according to claim 5, characterized in that, The differential friction mechanism includes a first friction roller and a second friction roller. The differential speed ratio between the first friction roller and the second friction roller is controlled between 1.3:1 and 1.8:1, and the normal compressive stress applied to the surface of the raw material by the differential friction mechanism is controlled between 0.5MPa and 2.0MPa. The generated shear stress τ follows the following relationship: τ=μ·Δv / h·σ, where μ is the dynamic friction coefficient between the film and paper, Δv is the difference in linear velocity between the first friction roller and the second friction roller, h is the thickness of the raw material under pressure, and σ is the normal compressive stress.

7. The sorting method according to claim 1, characterized in that, The dry purification process includes: Three-dimensional high-frequency vibration removal process, magnetic coupling collection process, and cyclone gas-solid separation process; The three-dimensional high-frequency vibration removal process is used to precipitate inorganic impurities on the surface of the strip fibers, the magnetic coupling collection process is used to collect the mixed fine magnetic metal foreign matter, and the cyclone gas-solid separation process is used to achieve the physical separation of paper strip fibers and light ash particles.

8. The sorting method according to claim 1, characterized in that, Also includes: The control unit 18 dynamically adjusts the process parameters of the thermal interface weakening sequence and the differential friction shearing sequence based on the processing feedback of the first material flow. The dynamic adjustment includes: Acquire an image of the surface of the paper substrate after the first material has been processed; Analyze the percentage of residual film area in the surface image; In response to the residual membrane area percentage exceeding a preset threshold, the temperature parameter of the thermal interface weakening step or the differential speed ratio parameter of the differential friction shearing step is adjusted.

9. A dual-channel collaborative sorting system for mixed-form pulp raw materials, characterized in that, include: The feeding and diversion device is used to receive mixed pulp raw materials and divert them into a first processing channel and a second processing channel according to their physical properties, so as to match differentiated processing processes for raw materials of different forms. The first processing subsystem, located within the first processing channel, includes a thermal interface weakening unit and a differential friction shearing unit. The thermal interface weakening unit is used to reduce the interfacial bonding strength between the film layer and the paper-based fiber layer. The differential friction shearing unit is used to apply tangential shear stress after the interfacial bonding strength is reduced, so as to collaboratively drive the film layer to undergo overall plastic slip-peeling from the paper-based fiber layer. The second processing subsystem, located within the second processing channel, includes a dry purification unit for dry purification of materials.

10. The sorting system according to claim 9, characterized in that, Also includes: The control unit is signal-connected to the feeding and diversion device, the first processing subsystem, and the second processing subsystem, and is used to dynamically adjust the process parameters of the thermal interface weakening unit and the differential friction shearing unit based on the processing feedback of the first processing subsystem.

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