Preparation method and application of ardealite-based fiberboard made of waste paper fibers

Abstract

The invention provides a preparation method and application of an ardealite-based fiberboard made of waste paper fibers, a base material used by the fiberboard is an industrial solid waste as a main precursor material, and the ardealite-based fiberboard comprises ardealite, garbage bottom ash and the waste paper fibers. The waste paper fibers and the PVA fibers are combined for toughening, so that the bending strength is improved. The method does not use cement and other traditional cementing materials, and is beneficial to energy conservation and emission reduction in the industrial field and the building field; most of the used raw materials are industrial solid wastes, so that the production process is simple, the reduction of the production cost is facilitated, the industrial solid wastes such as ardealite, waste paper fibers, garbage bottom ash and the like can generate an interaction reaction under the action of an exciting agent, and a remarkable synergistic enhancement effect is achieved; the used waste paper fibers and PVA fibers have a combined toughening effect, so that reinforcement and toughening in different scales can be realized. The ardealite fiberboard is simple and convenient in preparation process, and a pouring process and an extrusion process can be adopted.

Description

Technical Field

[0001] The present invention relates to the field of preparation of inorganic non-metallic materials, and more particularly, to a preparation method and application of a phosphogypsum-based fiber board made of waste paper fibers. Background Art

[0002] In the context of insufficient forest resources, raw material dependence on imports, and increasingly strict environmental protection policies, the comprehensive utilization of pulp fibers has become particularly important, and research in this field has gradually received more attention. To solve the raw material problem, large domestic paper-making enterprises have started to layout factories abroad, processing imported waste paper into recycled fiber pulp and transporting it back to China for use. This strategy not only optimizes the raw material structure but also injects new vitality into the sustainable development of the paper-making industry. Pulp fibers are not only used in traditional fields such as printing, packaging, and household paper but also find applications in emerging fields such as construction and fiber-reinforced silicate fireproof boards. Researchers are constantly exploring the application potential of pulp fibers in various fields, promoting the in-depth development of the comprehensive utilization of pulp fibers through technological innovation and product upgrading. The government has also introduced a series of policies to promote the transformation and upgrading of pulp fiber utilization, improve resource utilization efficiency, and promote green development. The implementation of policies such as "Several Opinions on Accelerating the Development of Circular Economy" and "Pollutant Discharge Standards for the Paper Industry" has prompted enterprises to increase environmental protection investment, improve environmental protection technology levels, and promote the sustainable development of the comprehensive utilization of pulp fibers. Waste paper, as the main raw material for recycled pulp, needs to undergo pretreatment steps such as classified recycling and sorting to remove impurities. These steps help to remove impurities such as plastics, metals, and inks, improving the quality of recycled pulp. At the same time, waste slurries such as printing and dyeing wastewater and electroplating waste liquid can also be used as raw materials for recycled pulp, but need to be purified first. Using pulp fibers in the preparation of building materials is an effective way to utilize waste pulp.

[0003] Fiber gypsum board has good quality and can promote the fire resistance, heat insulation and sound insulation of the product. Gypsum board is made mainly of gypsum and added with a certain proportion of fiber reinforcing materials. Traditional reinforcing fibers mainly include synthetic fibers such as glass fiber, carbon fiber, polypropylene fiber, etc., but these fibers have problems of high cost and potential environmental pollution. In recent years, biomass fibers such as wood fiber, sisal fiber and bamboo original fiber have attracted attention due to their environmental friendliness and renewability. Research shows that after proper treatment, these biomass fibers can significantly improve the strength, toughness and other properties of gypsum board. With the improvement of environmental awareness, the environmental problems in the preparation process of fiber gypsum board have also been increasingly emphasized. Researchers continuously explore environmentally friendly raw materials and preparation processes to reduce energy consumption and emissions during production. For example, using biomass fibers as reinforcing materials not only improves the properties of gypsum board, but also realizes the resource utilization of waste. In addition, by optimizing the production process and flow, the generation and emission of wastewater, waste gas and solid waste can be reduced, realizing the green and sustainable development of gypsum board production.

[0004] Phosphogypsum is a by-product of industrial production of phosphate fertilizer. In China, nearly 50 million tons of phosphogypsum are produced annually, and only about 20% of it is utilized. A large amount of untreated phosphogypsum is stacked, filled and directly discharged, polluting land and water resources. Making full use of phosphogypsum can not only protect the environment and realize resource reuse, but also promote economic development. As an industrial waste, phosphogypsum can be processed into hemihydrate calcium sulfate through a series of treatments and produce different crystals according to different treatment methods. These treated phosphogypsum can fully replace natural gypsum for production and be used to manufacture fiber gypsum board. In the production process of phosphogypsum-based fiber gypsum board, the performance of the board can be further improved by adding reinforcing modifiers and other methods. For example, using BCL emulsion to modify phosphogypsum-based rice straw fiber board can significantly improve the static bending strength of the board and reduce the water absorption rate, making it meet the national gypsum building material standard. In addition, phosphogypsum can be combined with agricultural residues to produce new green building materials such as phosphogypsum-based plant fiber board. This kind of board not only has environmental friendliness, but also can bring good economic, environmental and social benefits in practical applications.

[0005] With the in-depth research and continuous progress of technology, the technology of making fiber gypsum board with phosphogypsum will be more mature and perfect, providing more green, environmentally friendly and high-performance building material choices for the development of the construction industry. At the same time, this will also promote the comprehensive utilization of phosphogypsum, reduce the emission of industrial waste and realize the sustainable utilization of resources. Therefore, we propose a preparation method and application of phosphogypsum-based fiber board made of waste paper fiber. Summary of the Invention

[0006] The object of the present invention is to address the problems raised in the existing background art. To achieve the above-mentioned invention object, the present invention provides the following technical solutions: A preparation method of a phosphogypsum-based fiberboard made of waste paper fibers, comprising the following steps:

[0007] Step 1: Phosphogypsum is mixed with water at a solid-liquid ratio of 1:3 to form a gypsum slurry with a certain concentration. After flotation filtration, the filter cake is added with CaO to remove P2O5 water-soluble impurities, and finally, phosphogypsum-based β-calcium sulfate hemihydrate powder is obtained through low-temperature calcination treatment and applied to cast gypsum boards.

[0008] Step 2: Phosphogypsum, bottom ash of garbage, waste paper fibers, activator, fine sand and water are mixed in proportion. When the fluidity of the slurry is appropriate after stirring, PVA fibers are added and stirred.

[0009] Step 3: During forming, according to different fluidities and ratios, casting forming or extrusion forming is adopted.

[0010] As a preferred technical solution of the present invention, the base material used takes industrial solid waste as the main precursor material, including phosphogypsum, bottom ash of garbage, and waste paper fibers. The matrix cementing material is all solid waste. Under the action of the activator and the interaction of each solid waste material itself, the compressive strength of the matrix material reaches more than 30 MPa.

[0011] As a preferred technical solution of the present invention, the waste paper fibers and PVA fibers are combined to enhance toughness. Among them, the waste paper fibers play a toughening role by themselves, and the PVA fibers, as high-quality organic fibers, cooperate with the waste paper fibers to enhance toughness.

[0012] As a preferred technical solution of the present invention, the temperature range of the low-temperature calcination treatment is 130 - 180 °C, and the calcination time is 1 - 3 hours.

[0013] As a preferred technical solution of the present invention, when mixing phosphogypsum, bottom ash of garbage, waste paper fibers, activator, fine sand and water, the mass ratio of each component is: 30 - 60 parts of phosphogypsum, 10 - 30 parts of bottom ash of garbage, 5 - 20 parts of waste paper fibers, 1 - 5 parts of activator, 5 - 20 parts of fine sand, and the amount of water is based on achieving an appropriate fluidity of the slurry.

[0014] As a preferred technical solution of the present invention, the appropriate fluidity of the slurry means that the fluidity of the slurry is between 100 - 200 mm.

[0015] As a preferred technical solution of the present invention, the time for adding PVA fibers and stirring is 5 - 15 minutes to ensure that the PVA fibers are evenly dispersed in the slurry.

[0016] As a preferred technical solution of the present invention, for the paste with fluidity greater than 150 mm, casting molding is adopted; for the paste with fluidity less than or equal to 150 mm, extrusion molding is adopted.

[0017] As a preferred technical solution of the present invention, the formed fiberboard is cured at room temperature, and the curing time is 7 to 28 days.

[0018] An application of a preparation method of a phosphogypsum-based fiberboard made of waste paper fibers, wherein the waste paper fiber-reinforced phosphogypsum fiberboard material is applied to building materials.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] The method of the present invention utilizes industrial solid wastes such as phosphogypsum, waste paper fibers, and bottom ash of garbage, without using traditional gelling materials such as cement, which is beneficial to energy conservation and emission reduction in the industrial field and the construction field;

[0021] Since most of the raw materials used are industrial solid wastes, the production process is simple and the production cycle is short, which is beneficial to reducing production costs;

[0022] The industrial solid wastes such as phosphogypsum, waste paper fibers, and bottom ash of garbage used can produce interactive reactions under the action of an activator, and have a significant synergistic strengthening effect;

[0023] The waste paper fibers and PVA fibers used have a combined toughening effect, and can achieve strengthening and toughening at different scales.

[0024] The preparation process of the phosphogypsum fiberboard is simple, and both casting process and extrusion process can be adopted. Description of the Drawings

[0025] Figure 1 It is an experimental data graph provided by the present invention;

[0026] Figure 2 It is a flow chart provided by the present invention. Detailed Embodiments

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0028] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments may be combined with each other. It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0029] Embodiment 1: A preparation method of a phosphogypsum-based fiberboard made of waste paper fibers includes the following steps: Step 1: Phosphogypsum is mixed with water at a solid-liquid ratio of 1:3 to form a gypsum slurry with a certain concentration. After flotation and filtration, the filter cake is added with CaO to remove water-soluble P2O5 impurities, and finally, phosphogypsum-based β-calcium sulfate hemihydrate powder is obtained through low-temperature calcination treatment and applied to cast gypsum boards.

[0030] Step 2: Phosphogypsum, bottom ash of garbage, waste paper fibers, an activator, fine sand, and water are mixed in proportion. When the fluidity of the slurry is appropriate after stirring, PVA fibers are added and stirred.

[0031] Step 3: During molding, casting molding or extrusion molding is adopted according to different fluidities and ratios.

[0032] The base material used takes industrial solid wastes as the main precursor materials, including phosphogypsum, bottom ash of garbage, and waste paper fibers. The matrix cementing materials are all solid wastes. Under the action of the activator and the interaction of each solid waste material itself, the compressive strength of the matrix material reaches more than 30 MPa.

[0033] The waste paper fibers and PVA fibers are combined to enhance toughness. Among them, the waste paper fibers themselves play a toughening role, and the PVA fibers, as high-quality organic fibers, cooperate with the waste paper fibers to enhance toughness.

[0034] The temperature range of the low-temperature calcination treatment is 130 - 180 °C, and the calcination time is 1 - 3 hours.

[0035] When phosphogypsum, bottom ash of garbage, waste paper fibers, an activator, fine sand, and water are mixed, the mass ratios of the components are as follows: 30 - 60 parts of phosphogypsum, 10 - 30 parts of bottom ash of garbage, 5 - 20 parts of waste paper fibers, 1 - 5 parts of activator, 5 - 20 parts of fine sand, and the amount of water is determined to achieve an appropriate fluidity of the slurry.

[0036] Stirring until the fluidity of the slurry is appropriate means that the fluidity of the slurry is between 100 - 200 mm.

[0037] The stirring time with PVA fibers added is 5 to 15 minutes to ensure the uniform dispersion of PVA fibers in the slurry.

[0038] For the slurry with a fluidity greater than 150 mm, casting molding is adopted; for the slurry with a fluidity less than or equal to 150 mm, extrusion molding is adopted.

[0039] The formed fiberboard is cured at room temperature for 7 to 28 days.

[0040] The application of a preparation method of phosphogypsum-based fiberboard made from waste paper fibers, where the waste paper fiber-reinforced phosphogypsum fiberboard material is applied to building materials.

[0041] Experimental examples

[0042] Experiment on making phosphogypsum-based fiberboard with waste paper fibers

[0043] I. Experimental purpose

[0044] The purpose of this experiment is to explore the optimal preparation process and material ratio for making phosphogypsum-based fiberboard with waste paper fibers. By testing and analyzing the compressive strength, flexural strength, water resistance, fire resistance and other properties of the fiberboard under different ratios, the optimal solution that can meet the requirements of building materials is determined.

[0045] II. Experimental materials

[0046] 1. Phosphogypsum: As the main matrix material.

[0047] 2. Bottom ash of garbage: An industrial solid waste, which participates in the composition of the matrix material.

[0048] 3. Waste paper fibers: Play a toughening role and provide a certain toughness for the fiberboard.

[0049] 4. Activator: Promote the reaction between various solid waste materials and enhance the properties of the matrix material.

[0050] 5. Fine sand: Adjust the physical properties of the materials.

[0051] 6. PVA fibers: Cooperate with waste paper fibers to enhance toughness and improve the comprehensive properties of the fiberboard.

[0052] 7. Water: Used to adjust the fluidity of the slurry.

[0053] 8. CaO: Used to remove the water-soluble P2O5 impurities in phosphogypsum.

[0054] III. Experimental equipment

[0055] 1. Flotation and filtration equipment: Used for the flotation and filtration of phosphogypsum slurry.

[0056] 2. Low-temperature calcination furnace: The temperature can be controlled at 130 - 180 °C, and it is used for the low-temperature calcination treatment of phosphogypsum.

[0057] 3. Mixing equipment: It has sufficient mixing capacity and is used for mixing various materials.

[0058] 4. Fluidity tester: It measures the fluidity of the slurry.

[0059] 5. Molding die: It includes a casting molding die and an extrusion molding die.

[0060] 6. Pressure testing machine: It tests the compressive strength and flexural strength of the fiberboard.

[0061] 7. Water resistance testing equipment: It is used to test the water resistance of the fiberboard.

[0062] 8. Fire resistance testing equipment: It evaluates the fire resistance performance of the fiberboard.

[0063] IV. Experimental procedures

[0064] (I) Preparation of phosphogypsum-based β - hemihydrate calcium sulfate powder

[0065] 1. Make a gypsum slurry by adding water to phosphogypsum according to a solid-liquid ratio of 1:3.

[0066] 2. Use flotation filtration equipment to perform flotation filtration on the gypsum slurry to obtain a filter cake.

[0067] 3. Add CaO to the filter cake to remove P2O5 water-soluble impurities.

[0068] 4. Put the treated filter cake into a low-temperature calcination furnace and calcine it at a temperature range of 130 - 180 °C for 1 - 3 hours to obtain phosphogypsum-based β - hemihydrate calcium sulfate powder for standby.

[0069] (II) Preparation of fiberboard slurry

[0070] Mix phosphogypsum, bottom ash of garbage, waste paper fiber, activator, fine sand and water according to different mass ratios (see the following table for details), and use mixing equipment to mix them. During the mixing process, use a fluidity tester to monitor the fluidity of the slurry in real time until the fluidity of the slurry reaches between 100 - 200 mm.

[0071]

[0072] When the fluidity of the slurry is appropriate, add PVA fiber and continue to mix for 5 - 15 minutes to ensure that the PVA fiber is evenly dispersed in the slurry.

[0073] (III) Molding of fiberboard

[0074] Use a fluidity tester to measure the fluidity of the slurry again:

[0075] 1. If the fluidity of the slurry is greater than 150 mm, a casting mold is used for casting and molding.

[0076] 2. If the fluidity of the slurry is less than or equal to 150 mm, an extrusion mold is used for extrusion molding.

[0077] (IV) Curing of fiberboard

[0078] The formed fiberboard is cured at room temperature for 7 - 28 days.

[0079] V. Performance testing

[0080] A compression testing machine is used to test the compressive strength of the cured fiberboard, and the compressive strength values of each sample are recorded.

[0081] Similarly, a compression testing machine is used to test the flexural strength of the fiberboard to obtain flexural strength data.

[0082] The fiberboard samples are immersed in water for a certain period of time, and the water resistance percentage is calculated based on indicators such as mass change.

[0083] Fire resistance testing equipment is used to evaluate the fire resistance performance of the fiberboard and determine its fire resistance rating.

[0084] VI. Analysis of experimental results

[0085] Record the test results of the compressive strength, flexural strength, water resistance, and fire resistance of the fiberboards corresponding to each experimental number, and compare and analyze them with the data in the literature. Observe the effects of different material ratios and forming processes on the performance of the fiberboard, and find the optimal solution that can make the performance of the fiberboard reach the best. For example, analyze the influence laws of different dosages of phosphogypsum, bottom ash, waste paper fiber, and water on strength and water resistance, and determine the material ratio and preparation process that are most suitable for building materials requirements.

[0086] The above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above respective embodiments, the present invention is not limited to the above specific embodiments. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and their improvements that do not depart from the spirit and scope of the invention are covered by the scope of the claims of the present invention.

Claims

1. A preparation method of a phosphogypsum-based fiberboard made from waste paper fibers, characterized in that, It includes the following steps: Step 1: Phosphogypsum is mixed with water at a solid-liquid ratio of 1:3 to make a gypsum slurry with a certain concentration. After flotation filtration, the filter cake is added with CaO to remove water-soluble P2O5 impurities, and finally, β-hemihydrate calcium sulfate powder based on phosphogypsum is prepared by low-temperature calcination treatment and applied to cast gypsum boards. Step 2: Phosphogypsum, bottom ash of garbage, waste paper fiber, activator, fine sand and water are mixed in proportion. When the fluidity of the slurry is appropriate after stirring, PVA fiber is added and stirred. Step 3: During molding, depending on the different fluidity and ratios, casting molding or extrusion molding is adopted.

2. The preparation method of the phosphogypsum-based fiberboard made of waste paper fibers according to claim 1, wherein The base material used takes industrial solid waste as the main precursor material, including phosphogypsum, bottom ash of garbage, waste paper fiber. The matrix cementing material is all solid waste. Under the action of the activator and the interaction of various solid waste materials themselves, the compressive strength of the matrix material reaches more than 30 MPa.

3. The preparation method of a phosphogypsum-based fiberboard made of waste paper fibers according to claim 2, characterized in that, The waste paper fiber and PVA fiber are combined to enhance toughness. Among them, the waste paper fiber itself plays a toughening role, and the PVA fiber, as a high-quality organic fiber, synergistically toughens with the waste paper fiber.

4. The preparation method of a phosphogypsum-based fiberboard made of waste paper fibers according to claim 3, characterized in that, The temperature range of the low-temperature calcination treatment is 130 - 180 °C, and the calcination time is 1 - 3 hours.

5. The preparation method of a phosphogypsum-based fiberboard made of waste paper fibers according to claim 4, characterized in that, When mixing phosphogypsum, bottom ash of garbage, waste paper fiber, activator, fine sand and water, the mass ratio of each component is: 30 - 60 parts of phosphogypsum, 10 - 30 parts of bottom ash of garbage, 5 - 20 parts of waste paper fiber, 1 - 5 parts of activator, 5 - 20 parts of fine sand, and the amount of water is determined by achieving an appropriate fluidity of the slurry.

6. The preparation method of a phosphogypsum-based fiberboard made from waste paper fibers according to claim 5, characterized in that, Stirring until the fluidity of the slurry is appropriate means that the fluidity of the slurry is between 100 - 200 mm.

7. The preparation method of a phosphogypsum-based fiberboard made of waste paper fibers according to claim 6, characterized in that, The time for adding PVA fiber and stirring is 5 - 15 minutes to ensure that the PVA fiber is evenly dispersed in the slurry.

8. A preparation method of a phosphogypsum-based fiberboard made of waste paper fibers according to claim 7, characterized in that, When the fluidity of the slurry is greater than 150 mm, casting molding is adopted; when the fluidity of the slurry is less than or equal to 150 mm, extrusion molding is adopted.

9. The preparation method of the phosphogypsum-based fiberboard made of waste paper fibers according to claim 8, characterized in that, The formed fiberboard is cured at room temperature, and the curing time is 7 - 28 days.

10. Application of a preparation method of a phosphogypsum-based fiberboard made of waste paper fibers, characterized in that, The waste paper fiber-reinforced phosphogypsum fiberboard material is applied to building materials.

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