High-strength, high-water-resistance phosphogypsum building block

Abstract

The application discloses high-strength and high-water-resistance phosphogypsum building blocks and belongs to the technical field of building material processing. The raw materials of the high-strength and high-water-resistance phosphogypsum building blocks comprise phosphogypsum, a retarder, a water reducing agent, magnesium salt whiskers, polyvinyl alcohol and aluminosilicate; the length of the magnesium salt whiskers is less than 2 microns, and the granularity of the phosphogypsum is 100-150 meshes; the preparation method comprises the following steps: fully stirring the phosphogypsum, the magnesium salt whiskers, the water reducing agent, the retarder, the polyvinyl alcohol and the aluminosilicate, then adding water, pouring into a mold to obtain the phosphogypsum building blocks, and then curing. The length of the whiskers is less than 2 microns, and the granularity of the phosphogypsum is 100-150 meshes, so that the phosphogypsum building blocks show excellent compression resistance and folding resistance, and the water resistance coefficient of the phosphogypsum building blocks reaches 0.34, thereby showing good water resistance. In addition, the preparation method of the phosphogypsum building blocks has the advantages of simple process, fast demolding, high compression resistance, high folding resistance and high water resistance.

Description

Technical Field

[0001] This invention belongs to the field of building material processing technology, specifically relating to a high-strength, high-water-resistant phosphogypsum block. Background Technology

[0002] With the rapid development of industrialization and urbanization, the construction industry faces enormous environmental pressure, particularly the increasingly serious problem of construction solid waste disposal. Phosphogypsum, as an important industrial byproduct, is generated in large quantities in industries such as chemical engineering and gypsum board manufacturing, but its treatment and reuse rates are low, leading to increasingly prominent environmental pollution and resource waste problems. As a common solid waste, phosphogypsum, whose main component is CaSO4·2H2O, possesses certain mechanical strength and water resistance, and is widely used in building materials. However, pure phosphogypsum blocks have many shortcomings, such as poor compressive and flexural strength, weak water resistance, and limited environmental adaptability. These limitations restrict the widespread application of phosphogypsum as a building material.

[0003] Currently, common methods for treating phosphogypsum solid waste include the production of gypsum board and building materials. However, these methods have certain limitations in application. For example, gypsum board is prone to softening and deformation in humid environments, limiting its application outdoors or in high-humidity environments. Furthermore, the reuse of phosphogypsum faces challenges in terms of technology, economics, and environmental protection. How to effectively utilize this solid waste, increase its added value, and reduce its environmental impact is a pressing issue that needs to be addressed in the current building materials industry.

[0004] To address these issues, scientists and engineers began exploring combining phosphogypsum with other materials to improve its performance. Among these, fibers and whiskers, as novel reinforcing fillers, are considered ideal choices for improving the performance of phosphogypsum blocks due to their unique physical and chemical properties. Adding fibers and whiskers to traditional phosphogypsum blocks significantly improves their overall performance. This method not only enhances the structural integrity of the blocks but also effectively improves their compressive strength and water resistance, making them more suitable for use in various building structures. However, although the addition of fibers and whiskers improves the performance of phosphogypsum blocks to some extent, some challenges remain in practical applications. For example, insufficient compatibility between the added fibers or whiskers and phosphogypsum may lead to cracking of the phosphogypsum during long-term use. Furthermore, the uniform dispersion of fibers or whiskers is also a technical challenge, directly affecting the overall performance and quality of the blocks.

[0005] Most current research on phosphogypsum blocks focuses on one of the properties, namely compressive strength, flexural strength, or water resistance. There is relatively little research on phosphogypsum blocks that simultaneously achieve both compressive strength, flexural strength, and water resistance. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this invention proposes a high-strength, high-water-resistant phosphogypsum block.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a high-strength, high-water-resistant phosphogypsum block material, comprising phosphogypsum, retarder, water-reducing agent, magnesium salt whiskers, polyvinyl alcohol, and aluminosilicate; wherein the length of the magnesium salt whiskers is less than 2 μm, and the particle size of the phosphogypsum is 100-150 mesh.

[0008] The preparation method of the high-strength, high-water-resistant phosphogypsum blocks includes:

[0009] (1) Thoroughly mix phosphogypsum, magnesium salt whiskers, water-reducing agent, retarder, polyvinyl alcohol, and aluminosilicate, then add water and pour into a mold to obtain phosphogypsum blocks.

[0010] (2) Place the phosphogypsum blocks in a curing box for curing.

[0011] In a preferred embodiment of the present invention, the mass ratio of phosphogypsum, retarder, water-reducing agent, magnesium salt whiskers, polyvinyl alcohol and aluminosilicate is 98.05-99.29: 0.2-0.81: 0.17-0.4: 0.17-0.4: 0.08-0.21: 0.08-0.21.

[0012] Retarder, water-reducing agent and aluminosilicate are common pharmaceuticals in this field.

[0013] In a preferred embodiment of the present invention, the mass ratio of the water-reducing agent to the retarder is 1:1.

[0014] In a preferred embodiment of the present invention, the mass ratio of the phosphogypsum, retarder, water-reducing agent, magnesium salt whiskers, polyvinyl alcohol and aluminosilicate is 98.98:0.4:0.21:0.21:0.1:0.1.

[0015] In a preferred embodiment of the present invention, the mass of the water is 35% of the total mass of phosphogypsum, magnesium salt whiskers, water-reducing agent, retarder, polyvinyl alcohol, and aluminosilicate.

[0016] In a preferred embodiment of the present invention, the curing temperature is 20±2℃ and the curing time is 28 days.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: By precisely controlling the mixing ratio and stirring conditions of phosphogypsum powder, whiskers, and other additives, and by using 150-mesh phosphogypsum particles and whiskers with a length of less than 2 μm to synergistically improve the strength and stability of the blocks, the final blocks exhibit excellent compressive strength (30.23 MPa) and flexural strength (12.61 MPa), while also possessing good water resistance. Furthermore, the method for preparing phosphogypsum blocks according to this invention has advantages such as low cost, simple operation, and environmental friendliness. Attached Figure Description

[0018] Figure 1 The image shows a cross-sectional SEM image of the high-strength, high-water-resistant phosphogypsum block prepared in Example 1.

[0019] Figure 2 The diagram shows the compressive strength of the phosphogypsum blocks prepared in Examples 1-5 and Comparative Examples 1-6.

[0020] Figure 3 The diagram shows the flexural strength of the phosphogypsum blocks prepared in Examples 1-5 and Comparative Examples 1-6. Detailed Implementation

[0021] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0022] Example 1

[0023] A method for preparing high-strength, highly water-resistant phosphogypsum blocks includes the following steps:

[0024] (1) Weigh 1460g of phosphogypsum powder with a particle size of 150 mesh, 6g of magnesium salt whiskers (MgSO4) with a length of 1μm, 3g of water-reducing agent (PC-1050), 3g of retarder (SG-12P), 1.5g of polyvinyl alcohol polymer, and 1.5g of aluminosilicate.

[0025] (2) Place the weighed phosphogypsum powder, magnesium salt whiskers (MgSO4), water-reducing agent (PC-1050), retarder (SG-12P), polyvinyl alcohol polymer, and aluminosilicate into a bucket, and add 35% water of the total mass. Use a water drill mixer to mix thoroughly, and pour the well-mixed slurry into a mold.

[0026] (3) Place the mold in the curing box for curing. The curing temperature is 20±2℃ and the curing time is 24h.

[0027] like Figure 1 As shown, the high-strength, high-water-resistant phosphogypsum blocks are composed of sheet-like materials, with whiskers between the block particles, which serve to connect the particles and fill the pores.

[0028] Example 2

[0029] The only difference between the preparation method of a high-strength, high-water-resistant phosphogypsum block and Example 1 is that in step (1), 1460g of phosphogypsum powder with a particle size of 150 mesh, 3g of magnesium salt whiskers (MgSO4) with a length of 1.9μm, 2.5g of water-reducing agent (PC-1050), 2.5g of retarder (SG-12P), 1.2g of polyvinyl alcohol polymer, and 1.2g of aluminosilicate.

[0030] Example 3

[0031] The only difference between the preparation method of a high-strength, high-water-resistant phosphogypsum block and Example 1 is that in step (1), 1460g of phosphogypsum powder with a particle size of 150 mesh, 12g of magnesium salt whiskers (MgSO4) with a length of 1.5μm, 3.5g of water-reducing agent (PC-1050), 3.5g of retarder (SG-12P), 2g of polyvinyl alcohol polymer, and 2g of aluminosilicate.

[0032] Example 4

[0033] The only difference between the preparation method of a high-strength, high-water-resistant phosphogypsum block and Example 1 is that the particle size of the phosphogypsum powder in step (1) is 100 mesh.

[0034] Example 5

[0035] The only difference between the preparation method of a high-strength, high-water-resistant phosphogypsum block and Example 1 is that in step (1), 1460g of phosphogypsum powder with a particle size of 100 mesh, 12g of magnesium salt whiskers (MgSO4) with a length of 1.3μm, 5.8g of water-reducing agent (PC-1050), 5.8g of retarder (SG-12P), 2.5g of polyvinyl alcohol polymer, and 2.5g of aluminosilicate.

[0036] Comparative Example 1

[0037] The only difference between this comparative example and Example 1 is the preparation method of the high-strength, high-water-resistant phosphogypsum blocks: magnesium salt whiskers (MgSO4 whiskers) were not added.

[0038] Comparative Example 2

[0039] The only difference between the preparation method of the high-strength, high-water-resistant phosphogypsum blocks in this comparative example and Example 4 and Example 1 is that magnesium salt whiskers (MgSO4 whiskers) were not added.

[0040] Comparative Example 3

[0041] The only difference between this comparative example and Example 1 is that the preparation method of the high-strength, high-water-resistant phosphogypsum blocks is 60 mesh.

[0042] Comparative Example 4

[0043] The only difference between this comparative example and Example 1 is that the preparation method of the high-strength, high-water-resistant phosphogypsum blocks is 90 mesh.

[0044] Comparative Example 5

[0045] The only difference between this comparative example and the preparation method of the high-strength, high-water-resistant phosphogypsum block described in Example 4 is that the length of the magnesium salt whiskers (MgSO4 whiskers) is 2.2 μm.

[0046] Comparative Example 6

[0047] The only difference between this comparative example and the preparation method of the high-strength, high-water-resistant phosphogypsum blocks described in Example 4 is that the length of the magnesium salt whiskers (MgSO4 whiskers) is 3 μm and the particle size of the phosphogypsum powder is 60 mesh.

[0048] Example of effect

[0049] The compressive strength, flexural strength, and water resistance of the phosphogypsum blocks prepared in Examples 1-5 and Comparative Examples 1-6 were tested, and the results are shown in Table 1 and 2. Figure 2-3 .

[0050] Water resistance: The prepared phosphogypsum blocks were immersed in water, and the water resistance coefficient of the phosphogypsum blocks was measured. The higher the water resistance coefficient, the less water permeability the material has, and therefore the better the water resistance.

[0051] Table 1

[0052]

[0053] According to Table 1, Figure 2-3 The compressive and flexural properties of the blocks in Examples 1-5 are compared with those in Comparative Examples 1-6, showing that the compressive strength, flexural strength, and water resistance of the blocks in Examples 1-5 are all higher than those in Comparative Examples 1-6. Adding magnesium salt whiskers (MgSO4) increases the number of effective contact sites between the crystals in the composite material, and the whiskers also fill the pores. Under stress, the effective contact sites between the whiskers and the gypsum dihydrate crystals can disperse stress and reduce stress concentration.

[0054] As can be seen from Example 1 and Comparative Examples 3-6, magnesium salt whiskers (MgSO4) and phosphogypsum powder, after size control, can ensure the flexural and compressive strength of phosphogypsum blocks and also give them good water resistance.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-strength, high-water-resistant phosphogypsum block, characterized in that, Its raw materials include phosphogypsum, retarder, water-reducing agent, magnesium salt whiskers, polyvinyl alcohol and aluminosilicate; the length of the magnesium salt whiskers is less than 2μm, and the particle size of the phosphogypsum is 100-150 mesh. The preparation method of the high-strength, high-water-resistant phosphogypsum blocks includes: (1) Thoroughly mix phosphogypsum, magnesium salt whiskers, water-reducing agent, retarder, polyvinyl alcohol, and aluminosilicate, then add water and pour into a mold to obtain phosphogypsum blocks; (2) Place the phosphogypsum blocks in a curing box for curing; The mass ratio of the phosphogypsum, retarder, water-reducing agent, magnesium salt whiskers, polyvinyl alcohol and aluminosilicate is 98.05-99.29: 0.2-0.81: 0.17-0.4: 0.17-0.4: 0.08-0.21: 0.08-0.

21.

2. The high-strength, high-water-resistant phosphogypsum block as described in claim 1, characterized in that, The mass ratio of the water-reducing agent to the retarder is 1:

1.

3. The high-strength, high-water-resistant phosphogypsum block as described in claim 1, characterized in that, The mass ratio of the phosphogypsum, retarder, water-reducing agent, magnesium salt whiskers, polyvinyl alcohol, and aluminosilicate is 98.98:0.4:0.21:0.21:0.1:0.

1.

4. The high-strength, high-water-resistant phosphogypsum block as described in claim 1, characterized in that, The water mass is 35% of the total mass of phosphogypsum, magnesium salt whiskers, water-reducing agent, retarder, polyvinyl alcohol, and aluminosilicate.

5. The high-strength, high-water-resistant phosphogypsum block as described in claim 1, characterized in that, The curing temperature was 20±2℃, and the curing time was 28 days.

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