A boxboard papermaking system containing a complex mineral fiber

Abstract

The utility model relates to papermaking technical field and disclose a kind of boxboard papermaking system containing composite mineral fiber, including waste paper pulp pretreatment unit, composite mineral fiber preparation unit, slurry mixing unit, papermaking unit, quality detection unit and white water reuse unit;Form closed loop system by each unit connection, the synergistic effect of each unit of system, realize the goal of upgrading, efficiency, pollution reduction, emission reduction;Composite mineral fiber preparation unit is dispersed by attapulgite, modified by chitosan and compounded by sepiolite, significantly enhances the binding force of mineral fiber and pulp fiber, thereby improving paper performance;Part of wood fiber is replaced by composite mineral fiber, combined with white water reuse unit and the retention force of mineral fiber after chitosan modification is improved, greatly reduces the cost of waste paper unit consumption and auxiliary materials such as retention aid, defoaming agent.

Description

Technical Field

[0001] This utility model relates to the field of papermaking technology, specifically to a linerboard papermaking system containing composite mineral fibers. Background Technology

[0002] The paper industry is an important pillar industry of the national economy, but it currently faces three core problems:

[0003] (1) Shortage of fiber raw materials: The world is highly dependent on wood pulp. Over-logging has led to a shortage of forest resources. Although China has alleviated the contradiction through waste paper recycling and integrated forestry and paper production, the consumption of waste paper per unit remains high.

[0004] (2) The contradiction between paper strength and cost: Although high-filler paper can reduce costs, the filler will weaken the hydrogen bonding force between fibers, resulting in a decrease in paper strength. In addition, a large amount of retention aids, defoamers and other auxiliary materials are required, which will increase costs.

[0005] (3) High environmental pressure: The white water in the papermaking process has a high fiber content and low recycling rate, which not only wastes resources but also increases the wastewater treatment load, which does not conform to the green development trend of "low emission and low consumption".

[0006] Therefore, composite mineral fibers, as a novel material, can replace some wood fibers and fillers. Their natural mineral source, low viscosity, and high adsorption properties offer a possibility for solving the aforementioned problems. However, existing papermaking systems often lack dedicated preparation and integration units for composite mineral fibers, failing to fully utilize their advantages in replacing fibers and enhancing bonding strength, thus making it difficult to effectively solve the above problems. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a linerboard papermaking system containing composite mineral fibers. By integrating composite mineral fiber preparation, pulp treatment, testing and white water recycling functions, it achieves efficient and environmentally friendly production of linerboard paper.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is: a linerboard papermaking system containing composite mineral fibers, comprising:

[0009] The waste paper pulp pretreatment unit includes a screening device, a grading device and a purification device connected in sequence, which are used to remove impurities, grade and purify the waste paper pulp.

[0010] A composite mineral fiber preparation unit, comprising an attapulgite dispersion device, a chitosan modification device, and a compound mixing device, wherein the outlet of the attapulgite dispersion device is connected to the inlet of the chitosan modification device, and the outlet of the chitosan modification device is connected to the inlet of the compound mixing device.

[0011] The pulp mixing unit has its inlet connected to the outlet of the waste paper pulp pretreatment unit and the outlet of the composite mineral fiber preparation unit, respectively.

[0012] The papermaking unit has its inlet connected to the outlet of the slurry mixing unit, and the papermaking unit includes a headbox, a screen section, a pressing section, and a drying section.

[0013] A quality inspection unit, including a density tester and an ash content tester, is located at the discharge end of the papermaking unit;

[0014] The white water recycling unit includes a sedimentation tank and a filtration device. The inlet of the sedimentation tank is connected to the white water outlet of the papermaking unit, and the outlet of the filtration device is connected to the inlet of the waste paper pulp pretreatment unit.

[0015] Optionally, the screening device has a screen mesh size of 100-120 mesh, and the purification device adopts a pressure-type slag remover.

[0016] Optionally, the attapulgite dispersion device is equipped with an adjustable-speed stirring paddle, and the bottom of the attapulgite dispersion device is equipped with a discharge pipe with a valve, and the discharge pipe is connected to the inlet of the chitosan modification device through a pipeline.

[0017] Optionally, the chitosan modification device includes a mixing chamber and a pH adjustment component, and the inner wall of the mixing chamber is provided with a corrosion-resistant coating.

[0018] Optionally, the pH adjustment assembly includes an ammonia storage tank and a metering pump connected together, the outlet of which is in communication with the mixing chamber.

[0019] Optionally, the slurry mixing unit employs a double-helix conical mixer.

[0020] Optionally, the filtration device has a multi-layer filter structure, and the mesh size of the multi-layer filter increases sequentially from the inlet end to the outlet end.

[0021] Optionally, the quality testing unit further includes a bursting index tester and a ring crush index tester. The signal output terminals of each tester are connected to a central controller. The central controller is electrically connected to the feed regulating valve of the slurry mixing unit and is used to adjust the amount of composite mineral fiber added according to the test results.

[0022] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0023] (1) The composite mineral fiber preparation unit significantly enhances the bonding force between mineral fibers and pulp fibers through attapulgite dispersion, chitosan modification and sepiolite compounding, thereby improving paper performance; by replacing part of the wood fiber with composite mineral fiber, combined with the white water recycling unit and the improved retention of mineral fibers after chitosan modification, the waste paper consumption per unit and the cost of auxiliary materials such as retention aids and defoamers are greatly reduced.

[0024] (2) The white water reuse unit can reduce the fiber content in white water, thereby reducing wastewater discharge to meet the clean production goal of "reducing pollution and emissions".

[0025] (3) The quality inspection unit is linked with the central controller, which can adjust the amount of composite mineral fiber added in real time to ensure product quality stability. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the linerboard papermaking system containing composite mineral fibers in an embodiment of this utility model;

[0027] Figure 2 This is a schematic diagram of the structure of the waste paper pulp pretreatment unit, the composite mineral fiber preparation unit, and the white water recycling unit in this embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the chitosan modification device in an embodiment of this utility model; Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention. Example 1

[0030] like Figures 1-3 As shown, a linerboard papermaking system containing composite mineral fibers includes a waste paper pulp pretreatment unit, a composite mineral fiber preparation unit, a pulp mixing unit, a papermaking unit, a quality inspection unit, and a white water recycling unit. By connecting the waste paper pulp treatment, composite mineral fiber preparation, pulp mixing, papermaking, quality inspection, and white water recycling units to form a closed-loop system of "pretreatment-preparation-mixing-forming-inspection-recycling," the synergistic effect of each unit achieves the goals of quality improvement, efficiency enhancement, pollution reduction, and emission reduction. Furthermore, through the cyclical connection between the white water recycling unit and the waste paper pulp pretreatment unit, the fiber content in the white water can be directly reduced, resulting in an annual saving of 12,000 tons of waste paper.

[0031] The waste paper pulp pretreatment unit includes a screening device, a grading device, and a purification device, which are connected in sequence and are used to remove impurities, grade, and purify the waste paper pulp, respectively. The composite mineral fiber preparation unit includes an attapulgite dispersion device, a chitosan modification device, and a compound mixing device. The outlet of the attapulgite dispersion device is connected to the inlet of the chitosan modification device, and the outlet of the chitosan modification device is connected to the inlet of the compound mixing device.

[0032] The inlet of the pulp mixing unit is connected to the outlet of the waste paper pulp pretreatment unit and the outlet of the composite mineral fiber preparation unit, respectively, and the inlet of the papermaking unit is connected to the outlet of the pulp mixing unit.

[0033] The quality inspection unit includes a density tester, an ash content tester, a bursting strength index tester, and a ring crush index tester. All of the aforementioned testers adopt existing technology and are located at the discharge end of the papermaking unit. The signal output terminals of each tester are connected to the central controller, which is electrically connected to the feed regulating valve of the slurry mixing unit to adjust the amount of composite mineral fiber added based on the test results.

[0034] The white water recycling unit includes a sedimentation tank and a filtration device. The inlet of the sedimentation tank is connected to the white water outlet of the papermaking unit, and the outlet of the filtration device is connected to the inlet of the waste paper pulp pretreatment unit, forming a circulation loop.

[0035] In response to the problems of fiber shortage, insufficient paper strength, high consumption of auxiliary materials, and waste of white water resources in existing technologies, this utility model achieves efficient and environmentally friendly production of linerboard by integrating functions of composite mineral fiber preparation, pulp treatment, testing, and white water recycling.

[0036] like Figures 2-3 As shown, the papermaking unit includes a headbox, a wire section, a press section, and a drying section. The headbox is used to evenly distribute the mixed pulp and spray it onto the forming wire of the wire section. The wire section dewaters the fibers through gravity dewatering and vacuum dewatering to form a wet paper web. The press section further dewaters and increases the paper density through mechanical pressure. The drying section reduces the moisture content of the wet paper web to the requirements of the finished paper through heat conduction or hot air drying. The papermaking process of the papermaking unit is a mature existing technology and will not be described in detail here.

[0037] The attapulgite dispersion device is equipped with an adjustable stirring paddle (800-1500 r / min), which can precisely control the stirring intensity according to the characteristics of attapulgite and dispersion requirements. The bottom of the attapulgite dispersion device is equipped with a discharge pipe with a valve, and the discharge pipe is connected to the inlet of the chitosan modification device through a pipeline. The bottom valved discharge pipe is connected to the inlet pipeline of the chitosan modification device, so that the attapulgite dispersion device can be seamlessly connected to the subsequent chitosan modification device.

[0038] In the initial stage of attapulgite dispersion, a higher rotation speed (e.g., 1200-1500 r / min) can rapidly break the agglomeration between attapulgite particles due to strong shear force, allowing the dense crystalline bundle structure to disperse quickly. As the dispersion process progresses, the rotation speed is reduced (e.g., 800-1000 r / min) to maintain the dispersion state and prevent excessive shearing that could lead to excessive particle breakage and affect performance. This ensures that the attapulgite is fully dispersed into loose rod-shaped crystals in the liquid medium, creating conditions for subsequent uniform mixing with chitosan and for it to exert its effect of enhancing paper properties, thereby improving the quality of the composite mineral fibers and ultimately enhancing the strength, stiffness, and other physical properties of the linerboard.

[0039] Once the attapulgite has dispersed to the desired effect, the valve is opened, and the well-dispersed attapulgite suspension can be directly transported to the chitosan modification unit without the need for complex intermediate transfer operations. This avoids material loss and contamination during the transfer process and improves production efficiency.

[0040] Precise stirring speed control and smooth material delivery reduce the dispersion time required for attapulgite, preventing dispersion quality from being affected by excessively long or short dispersion times. Stable dispersion quality ensures the consistency of the composite mineral fiber properties in each batch, thereby guaranteeing stable linerboard quality, reducing the risk of product quality fluctuations, and decreasing the defect rate. Furthermore, continuous production shortens the production cycle, improves equipment utilization, reduces production costs, and enhances the product's competitiveness in the market.

[0041] The chitosan modification device includes a mixing chamber and a pH adjustment component. The mixing chamber provides a stable space for mixing chitosan and attapulgite. During the mixing process, the two can come into full contact and achieve uniform dispersion through stirring and other methods. This allows chitosan molecules to interact with the surface of attapulgite, forming specific chemical bonds or adsorption layers, thereby changing the surface properties of attapulgite and improving its performance in the papermaking process.

[0042] The inner wall of the mixing chamber is coated with a corrosion-resistant coating, which effectively protects the equipment from the corrosive effects of chitosan solution, acetic acid solution, and chemicals generated during the reaction. For example, the acetic acid solution used to generate the chitosan solution is corrosive, and prolonged contact with the inner wall of the equipment can lead to damage and a shortened lifespan. The corrosion-resistant coating, or protective film, significantly extends the equipment's lifespan, reduces maintenance and replacement costs, and ensures continuous production.

[0043] The pH adjustment assembly includes an ammonia storage tank and a metering pump. The metering pump is installed at the output end of the ammonia storage tank, which stores ammonia for pH adjustment, and the outlet of the metering pump is connected to the mixing chamber.

[0044] Metering pumps can precisely control the amount of ammonia added. In the process of chitosan-modified attapulgite, pH value has a significant impact on the reaction process and the performance of the product. By precisely adding ammonia using a metering pump, the pH value of the reaction system can be controlled within a suitable range, which can promote the adsorption and solidification of chitosan on the surface of attapulgite, form an ideal chitosan deposition film, enhance the surface potential and particle size of attapulgite, and improve its binding force with fibers.

[0045] In the papermaking process, stable modified attapulgite properties can ensure the stability of paper quality, reduce paper quality problems caused by fluctuations in raw material properties, and improve product consistency and reliability.

[0046] The white water recycling unit's filtration system features a multi-layer filter structure, with the mesh size increasing sequentially from the inlet to the outlet. This multi-layer, increasing mesh size structure enables tiered filtration of the white water. The lower-mesh-size filter at the inlet intercepts larger impurities such as fibers and filler particles, preventing them from clogging subsequent, finer filters. As the water flows further downstream, the progressively larger mesh sizes filter out increasingly finer particles, such as fine fibers and colloids.

[0047] This coarse-to-fine filtration method can more comprehensively and efficiently remove impurities of different particle sizes from white water, significantly improving the filtration effect and resulting in purer recycled white water. This reduces the adverse effects of impurities on the papermaking process, thereby improving the quality of the finished paper. Furthermore, the tiered filtration reduces the burden on each filter layer. Large particles are intercepted at the front end, preventing them from directly impacting the finer filter at the back end, thus reducing the risk of filter damage and clogging.

[0048] Workflow:

[0049] Waste paper pulp pretreatment: Waste paper pulp is screened, graded, and purified to remove impurities and grade fibers, resulting in pure pulp;

[0050] Preparation of composite mineral fibers: Attapulgite dispersion → chitosan modification → sepiolite compounding, to obtain highly adsorbent composite mineral fibers;

[0051] Slurry mixing: The pretreated slurry and composite mineral fibers are evenly mixed in the mixing unit by spiral stirring;

[0052] Papermaking: The mixed pulp is sprayed onto the forming wire of the wire section through the headbox to dewater and form the paper web, so that the fibers interweave to form a wet paper web; then the press section further dewaters and increases the paper density through mechanical pressure (such as press rolls); finally, the drying section reduces the moisture content of the wet paper web to the requirements of the finished paper through heat conduction or hot air drying.

[0053] Quality inspection: Real-time monitoring of finished paper density, strength and other indicators, and adjustment of mineral fiber addition amount through central controller;

[0054] White water reuse: The white water generated during the forming and pressing process is precipitated and filtered to recover fibers and mineral fibers, which are then reused in the waste paper pulp pretreatment unit. Example 2

[0055] Based on Embodiment 1, this utility model also proposes specific equipment that can be used in the above-mentioned units, including but not limited to the following models.

[0056] Screening devices are used to remove coarse impurities (such as plastic sheets, metal blocks, fiber bundles, etc.) from waste paper pulp. Pressure screens (such as the Cascade series) can be used, with a screen mesh of 100-120 mesh. The rotating blade generates pulses, which force the fibers through the screen gaps / holes, while the impurities are intercepted and discharged.

[0057] The grading device is used to separate waste paper pulp into long fibers (>1.5mm) and short fibers (0.5-1.5mm) according to fiber length. A pressure fiber grading screen (such as the HydroCyclone grading system) can be used to separate long and short fibers by using centrifugal force. Long fibers are discharged from the top and short fibers are collected from the bottom.

[0058] The purification device is used to remove impurities from waste paper pulp while reducing fiber loss. A pressure-type descaling device (such as the HydroCyclone series HC150) can be used, with a speed of 1500-2000 r / min. It adopts an involute feed design to reduce eddy current loss and achieves an impurity removal rate of >98%. The speed can be precisely controlled by a variable frequency motor.

[0059] Attapulgite dispersion devices are used to disperse attapulgite from a dense crystalline bundle structure into a loose rod-shaped crystal, forming a uniform and stable suspension. High-speed shear dispersers (such as the ULTRA-TURRAX series) can be used, which generate strong shear force through high-speed rotor rotation (linear speed can reach 20-40m / s) to break up attapulgite agglomerates.

[0060] The chitosan modification device is used to achieve uniform coating of chitosan on attapulgite to form a stable modified complex. A high-shear mixing reactor (such as the YXPR-G type) can be used, which generates strong turbulence at a speed of 1600-2000 r / min through a three-layer sawtooth rotor-stator structure, promoting the adsorption of chitosan molecules onto the surface of attapulgite.

[0061] The compounding and mixing device is used to mix modified attapulgite and sepiolite in a certain proportion to form composite mineral fibers. An airflow mixer (such as the Hosokawa Alpine AFG series) can be used. The high-pressure airflow fluidizes the material in a closed container and achieves uniform mixing through turbulence. It can achieve precise compounding of sepiolite and attapulgite at a mass ratio of 1:5.

[0062] The slurry mixing unit can use an existing double-helix conical mixer (such as BEPEX products). The two asymmetric helices revolve around the cone wall while rotating on their own axis, forming a dual mixing effect of "convection + shear", which is suitable for high-viscosity slurries (such as slurries with added chitosan-modified attapulgite). Example 3

[0063] Based on Embodiment 1, this utility model also proposes specific papermaking parameters.

[0064] Waste paper pulp pretreatment unit: The screening device uses a 110-mesh screen to remove impurities with a particle size >0.15mm; the grading device separates fibers into long fibers (>1.5mm) and short fibers (0.5-1.5mm); the purification device is a pressure slag remover (speed 1800r / min) to remove light impurities.

[0065] Composite mineral fiber preparation unit:

[0066] Attapulgite dispersion device: Attapulgite and water are mixed in a mixing tank at a mass ratio of 1:7, the mixing speed is 1200 r / min, and the time is 60 min to obtain a rod-shaped attapulgite suspension;

[0067] Chitosan modification device: 2wt% chitosan solution (dissolved in 1.5wt% acetic acid) and attapulgite suspension are mixed at a volume ratio of 1:4, stirred at 1600r / min for 30min, and 8wt% ammonia water is added to adjust the pH to 8.0 to form chitosan-coated attapulgite.

[0068] Compound mixing device: sepiolite and chitosan-attapulgite are mixed at a mass ratio of 1:5, with a stirring speed of 800 r / min and a time of 30 min to obtain composite mineral fibers;

[0069] Slurry mixing unit: The amount of composite mineral fiber added is 8% of the oven-dry weight of the slurry.

[0070] White water recycling unit: The filtration device adopts a multi-layer filter screen of 60 mesh (inlet), 100 mesh (middle layer), and 150 mesh (outlet), with a recovery rate of ≥90%.

[0071] Test results: Finished paper density 0.78 g / cm³, bursting strength index 2.50 kPa・m² / g, ring crush index 8.50 N・m / g, ash content 12.5%; retention aid consumption 0.30 kg / t, defoamer consumption 0.32 kg / t, waste paper consumption 1.052 t / t.

[0072] Furthermore, this utility model also proposes some comparative embodiments.

[0073] A (No composite mineral fiber preparation unit): In this system, traditional calcium carbonate filler is directly used to replace composite mineral fibers, and the other parameters are the same as in Example 3.

[0074] Test results: The bursting index of the finished paper was 2.10 kPa·m² / g (lower than Example 3), the retention aid consumption was 0.36 kg / t (higher than Example 3), and the fiber content in the white water increased by 25% due to the weak bonding force between the filler and the fiber.

[0075] B (No White Water Recycling Unit): White water in the system is discharged directly, and other parameters are the same as in Example 3.

[0076] Test results: Waste paper consumption per unit was 1.120 t / t (higher than in Example 3), 15,000 tons of waste paper were wasted annually, and the COD value of wastewater increased by 30%.

[0077] C (Closed-loop control without quality inspection): The quality inspection unit only records data and does not adjust the amount of mineral fiber added in conjunction with the process. The other parameters are the same as in Example 3.

[0078] Test results: The ash content of the finished paper fluctuated between 11.0% and 14.0% (12.5% ​​± 0.5% in Example 3), and the pass rate was only 88% (99% in Example 3).

[0079] In summary, the papermaking system proposed in this utility model is used to manufacture linerboard containing composite mineral fibers. Through the synergistic effect of each unit, the high-efficiency application of composite mineral fibers is achieved, solving the problems of fiber shortage, insufficient strength, and serious pollution in traditional papermaking systems. It has significant economic benefits and environmental value.

[0080] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0081] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0082] Based on the preferred embodiments of this utility model described above, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A linerboard papermaking system containing composite mineral fibers, characterized in that, include: The waste paper pulp pretreatment unit includes a screening device, a grading device and a purification device connected in sequence, which are used to remove impurities, grade and purify the waste paper pulp. A composite mineral fiber preparation unit, comprising an attapulgite dispersion device, a chitosan modification device, and a compound mixing device, wherein the outlet of the attapulgite dispersion device is connected to the inlet of the chitosan modification device, and the outlet of the chitosan modification device is connected to the inlet of the compound mixing device. The pulp mixing unit has its inlet connected to the outlet of the waste paper pulp pretreatment unit and the outlet of the composite mineral fiber preparation unit, respectively. The papermaking unit has its inlet connected to the outlet of the slurry mixing unit, and the papermaking unit includes a headbox, a screen section, a pressing section, and a drying section. A quality inspection unit, including a density tester and an ash content tester, is located at the discharge end of the papermaking unit; The white water recycling unit includes a sedimentation tank and a filtration device. The inlet of the sedimentation tank is connected to the white water outlet of the papermaking unit, and the outlet of the filtration device is connected to the inlet of the waste paper pulp pretreatment unit.

2. The linerboard papermaking system containing composite mineral fibers according to claim 1, characterized in that, The screening device has a screen mesh size of 100-120 mesh, and the purification device adopts a pressure slag remover.

3. The linerboard papermaking system containing composite mineral fibers according to claim 1, characterized in that, The attapulgite dispersion device is equipped with an adjustable-speed stirring paddle inside. The bottom of the attapulgite dispersion device is equipped with a discharge pipe with a valve, and the discharge pipe is connected to the inlet of the chitosan modification device through a pipeline.

4. The linerboard papermaking system containing composite mineral fibers according to claim 1, characterized in that, The chitosan modification device includes a mixing chamber and a pH adjustment component, and the inner wall of the mixing chamber is provided with a corrosion-resistant coating.

5. The linerboard papermaking system containing composite mineral fibers according to claim 4, characterized in that, The pH adjustment assembly includes an ammonia storage tank and a metering pump connected together, with the outlet of the metering pump communicating with the mixing chamber.

6. The linerboard papermaking system containing composite mineral fibers according to claim 1, characterized in that, The slurry mixing unit uses a double-spiral conical mixer.

7. The linerboard papermaking system containing composite mineral fibers according to claim 1, characterized in that, The filtration device has a multi-layer filter structure, and the mesh size of the multi-layer filter increases sequentially from the inlet end to the outlet end.

8. The linerboard papermaking system containing composite mineral fibers according to claim 1, characterized in that, The quality testing unit also includes a bursting index tester and a ring crush index tester. The signal output terminals of each tester are connected to the central controller. The central controller is electrically connected to the feed regulating valve of the slurry mixing unit and is used to adjust the amount of composite mineral fiber added according to the test results.

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