Phosphogypsum building material, preparation method thereof and wallboard prepared from the same

Abstract

The present application relates to the technical field of phosphogypsum, and discloses a phosphogypsum building material, a preparation method thereof, and a wallboard prepared from the phosphogypsum building material, to solve the problem that the existing phosphogypsum building material can only be used for some substrates or some wall bodies, i.e., the application range is narrow and the popularization is poor.The phosphogypsum building material comprises, by weight, 400-450 parts of phosphogypsum, 12-35 parts of hydrophilic modified polystyrene, 10-20 parts of fluorine-containing nano TiO2, 10-25 parts of rigid fiber, 3-10 parts of white cement, 2-10 parts of cellulose ether, 2-10 parts of polyethylene glycol, and 0.5-5 parts of a retarder; wherein the hydrophilic modified polystyrene comprises crosslinked polystyrene, an organic base, carbon black and / or graphene, and paraffin wax.The phosphogypsum building material of the present application can maintain long-term stability under the effects of heat preservation and sound insulation by controlling the composition and structure of raw materials, and is suitable for different-shaped wall bodies.

Description

Technical Field

[0001] This invention relates to the field of phosphogypsum technology, and more specifically, to a phosphogypsum building material and its preparation method, and a wall panel prepared therefrom. Background Technology

[0002] Phosphogypsum is a solid waste generated during the wet-process phosphoric acid production. Its main components are calcium sulfate dihydrate, as well as incompletely decomposed phosphate rock, residual phosphoric acid, fluorides, acid-insoluble substances, and organic matter. The indiscriminate accumulation and discharge of phosphogypsum severely damages the ecological environment, polluting groundwater resources and wasting land resources. Therefore, the resource utilization of phosphogypsum has become an important research topic in building materials, chemical, agricultural, and other related fields.

[0003] In the construction industry, the technology for producing building materials using phosphogypsum is relatively mature. Currently, phosphogypsum building materials are mostly used to make wall panels or as wall coatings applied to wall surfaces.

[0004] For example, patent CN116290585A discloses a construction method for a composite waterproof and thermal insulation wall panel. The waterproof concrete used as the wall base includes cement, phosphogypsum, perlite, ordinary aggregate, composite aggregate, magnesium oxide, sodium silicate, titanium dioxide, polyacrylamide, and waterproofing agent. By adjusting the amount of cement and phosphogypsum, the above solution can avoid problems such as cracking of concrete due to excessive temperature stress.

[0005] For example, patent CN115159936A provides a plastering mortar and its preparation method and application, which includes engineering waste soil, graded sand, blast furnace slag, fly ash, industrial by-product gypsum, redispersible latex powder and fiber, etc. The raw materials of this plastering mortar work synergistically and are tightly combined through chemical and physical actions, giving it advantages such as high strength, low shrinkage and good decorative effect.

[0006] However, the strength, heat insulation, and waterproofing properties of existing phosphogypsum building materials are limited by their application scenarios, meaning they can only be used on certain substrates or walls in certain situations, resulting in a narrow range of applications and poor promotion. For example, applying existing phosphogypsum coatings to brick or log walls can lead to severe moisture absorption and subsequent wall damage; applying existing phosphogypsum building materials to irregularly shaped buildings, such as curved walls, can easily cause expansion and peeling. Overall, these problems arise because phosphogypsum building materials themselves have poor material stability, leading to changes in their structure and properties during use, thus affecting their normal use in buildings.

[0007] Based on the above situation, there is an urgent need for a phosphogypsum building material with good comprehensive performance and strong material stability. Summary of the Invention

[0008] The technical problem to be solved by this invention:

[0009] Currently, existing phosphogypsum building materials can only be used on certain substrates or walls in certain scenarios, resulting in a narrow range of applications and poor promotion. Specifically, this problem arises because phosphogypsum building materials themselves have poor material stability, leading to changes in their structure and performance during use, which in turn affects their normal use in buildings.

[0010] The technical solution adopted in this invention is as follows:

[0011] This invention provides a phosphogypsum building material, comprising, by weight, 400-450 parts phosphogypsum, 12-35 parts hydrophilic modified polystyrene, 10-20 parts fluorine-containing nano-TiO2, 10-25 parts rigid fiber, 3-10 parts white cement, 2-10 parts cellulose ether, 2-10 parts polyethylene glycol, and 0.5-5 parts retarder;

[0012] The method for preparing the hydrophilic modified polystyrene includes the following steps:

[0013] A1 involves mixing cross-linked polystyrene with an organic base, heating, and separating to obtain hydrophilic polystyrene.

[0014] A2 dissolves hydrophilic polystyrene in a solvent, adds 12-25% carbon black and / or graphene by mass, heats and stirs continuously, then adds paraffin while hot and mixes well to obtain hydrophilic modified polystyrene.

[0015] Preferably, the fluorine-containing nano-TiO2 is obtained by in-situ composite introduction of fluorine monomers into TiO2 nanoparticles.

[0016] Preferably, in step A1, the weight ratio of cross-linked polystyrene to organic base is controlled to be 1:15-22.

[0017] Preferably, in step A2, the mass of added carbon black and / or graphene accounts for 12-25% of the mass of hydrophilic polystyrene, and the mass of added paraffin accounts for 3-10% of the total mass of hydrophilic modified polystyrene.

[0018] Preferably, in step A1, the heating temperature is 40-80℃; in step A2, the heating temperature is 80-100℃.

[0019] The preparation method of the phosphogypsum building material described above includes the following steps:

[0020] S1 Take phosphogypsum, fluorine-containing nano-TiO2, and rigid fibers, stir and mix them to obtain mixture I;

[0021] S2 adds white cement, cellulose ether, polyethylene glycol, and retarder to mixture I, stirs and mixes, granulates, and obtains mixture II;

[0022] S3 prepares hydrophilic modified polystyrene, sprays hydrophilic modified polystyrene onto the surface of mixture II, and dries to obtain phosphogypsum building material particles.

[0023] Preferably, when spraying hydrophilic modified polystyrene, the thickness of the hydrophilic modified polystyrene is controlled to be 40-65% of the particle size of mixture II.

[0024] A wall panel prepared from the above-mentioned phosphogypsum building material; the preparation method of the wall panel is as follows: the phosphogypsum building material is mixed with concrete and poured into a mold to obtain the wall panel.

[0025] Preferably, when the phosphogypsum building material is mixed with concrete, the phosphogypsum building material accounts for 30-60% of the total material mass.

[0026] The technical mechanism and beneficial effects of this invention:

[0027] The phosphogypsum building material of this invention, through improvements to the raw materials and preparation methods, can solve the problems of poor stability of existing phosphogypsum materials. Furthermore, the walls prepared using the phosphogypsum building material of this invention have excellent properties of being lightweight and having high strength, thereby improving the performance and lifespan of the walls.

[0028] Specifically, hydrophilic modified polystyrene and hydrophobic fluorinated nano-TiO2 were introduced into the phosphogypsum system, resulting in a phosphogypsum building material with a hydrophilic and dense outer layer and a hydrophobic and porous inner core. Since phosphogypsum building materials need to be mixed with water to form a slurry before being applied to wall surfaces or cast into shape, the dense outer layer prevents excessive moisture from entering the material and causing damage, while the porous inner core provides sound insulation and heat preservation. Furthermore, the inclusion of rigid carbon fibers ensures strong structural stability during application, maintaining structural integrity even when forming irregularly shaped walls, preventing wall detachment or cracking. Detailed Implementation

[0029] 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] This invention provides a phosphogypsum building material and its preparation method, and a wall panel prepared therefrom. By weight, the phosphogypsum building material includes 400-450 parts of phosphogypsum, 12-35 parts of hydrophilic modified polystyrene, 10-20 parts of fluorine-containing nano-TiO2, 10-25 parts of rigid fiber, 3-10 parts of white cement, 2-10 parts of cellulose ether, 2-10 parts of polyethylene glycol, and 0.5-5 parts of retarder.

[0031] The method for preparing hydrophilic modified polystyrene in this invention is as follows:

[0032] A1 is prepared by mixing cross-linked polystyrene with an organic base at a weight ratio of 1:15-22, heating to 40-80℃, and filtering the reaction product after the reaction is complete. The solid obtained by filtration is washed with ethanol and dried to obtain hydrophilic polystyrene.

[0033] A2 dissolves hydrophilic polystyrene in N,N-dimethylformamide, adds carbon black and / or graphene, the mass of carbon black and / or graphene being 12-25% of the mass of hydrophilic polystyrene, heats and stirs continuously for 5-7 hours; then adds paraffin wax while hot, the amount of paraffin wax being 3-10% of the total mass of hydrophilic modified polystyrene, mixes well, and obtains hydrophilic modified polystyrene.

[0034] The method for preparing fluorine-containing nano-TiO2 in this invention is as follows:

[0035] Equimolar amounts of methacryloxypropyltrimethoxysilane (MPTMS), N-methylperfluorooctylsulfonylaminoethyl acrylate (MPSAEA), and methyl methacrylate were copolymerized, and fluorine-containing monomers were introduced during the copolymerization process. Then, TiO2 nanoparticles were introduced through in-situ composite technology to obtain homogeneous and transparent fluorine-containing nano-TiO2.

[0036] In this invention, those skilled in the art can select other existing hydrophobic fluorinated materials to replace fluorinated nano-TiO2 according to the actual situation, so that raw materials such as phosphogypsum can always be placed in the core of the material to achieve stable heat preservation and sound insulation functions.

[0037] The preparation method of phosphogypsum building material in this invention includes the following steps:

[0038] S1 Take phosphogypsum, fluorine-containing nano-TiO2, and rigid fibers, stir and mix them to obtain mixture I;

[0039] S2 adds white cement, cellulose ether, polyethylene glycol, and retarder to mixture I, stirs and mixes, granulates, and obtains mixture II;

[0040] S3 prepares hydrophilic modified polystyrene, sprays hydrophilic modified polystyrene onto the surface of mixture II, and dries to obtain phosphogypsum building material particles.

[0041] When spraying hydrophilic modified polystyrene, the thickness of the hydrophilic modified polystyrene should be controlled to be 40-65% of the particle size of mixture II.

[0042] In this invention, by mixing the above-mentioned phosphogypsum building material with concrete and casting it into shape, a lightweight and high-strength wall panel can be obtained; wherein, when the phosphogypsum building material is mixed with concrete, the phosphogypsum building material accounts for 30-60% of the total material mass.

[0043] <Example>

[0044] Example 1

[0045] (1) Take 420 parts of phosphogypsum, 12 parts of fluorine-containing nano-TiO2 and 20 parts of steel carbon fiber by weight, and stir at 800 r / min for 35 min to obtain mixture I;

[0046] (2) Add 3 parts cellulose ether, 4.5 parts polyethylene glycol, 5 parts white cement and 1.5 parts P-type gypsum retarder to mixture I, heat to about 60°C, stir at 450 r / min for 10 min, dry and granulate to obtain mixture II;

[0047] (3) Preparation of hydrophilic modified polystyrene: Crosslinked polystyrene and diethanolamine were mixed at a weight ratio of 1:15-22 and heated to 550°C. After the reaction was complete, the reaction product was filtered. The solid obtained by filtration was washed with ethanol and dried to obtain hydrophilic polystyrene.

[0048] Hydrophilic polystyrene was dissolved in N,N-dimethylformamide, and carbon black was added, with the amount of carbon black accounting for 16% of the mass of hydrophilic polystyrene. The mixture was heated and stirred continuously for 6 hours. Then, paraffin wax was added while the mixture was still hot, with the amount of paraffin wax accounting for 5% of the total mass of the hydrophilic modified polystyrene. The mixture was stirred well to obtain hydrophilic modified polystyrene.

[0049] (4) Take 22 parts of hydrophilic modified polystyrene, spray it on the surface of mixture II, and dry it to obtain phosphogypsum building material particles.

[0050] Example 2

[0051] (1) Take 420 parts of phosphogypsum, 12 parts of fluorine-containing nano-TiO2 and 20 parts of steel carbon fiber by weight, and stir at 800 r / min for 35 min to obtain mixture I;

[0052] (2) Add 3 parts cellulose ether, 4.5 parts polyethylene glycol, 3 parts white cement and 1.5 parts P-type gypsum retarder to mixture I, heat to about 60°C, stir at 450 r / min for 10 min, dry and granulate to obtain mixture II;

[0053] (3) Preparation of hydrophilic modified polystyrene: Crosslinked polystyrene and diethanolamine were mixed at a weight ratio of 1:15-22 and heated to 550°C. After the reaction was complete, the reaction product was filtered. The solid obtained by filtration was washed with ethanol and dried to obtain hydrophilic polystyrene.

[0054] Hydrophilic polystyrene was dissolved in N,N-dimethylformamide, and graphene was added. The amount of graphene added accounted for 18% of the mass of hydrophilic polystyrene. The mixture was heated and stirred continuously for 6 hours. Then, paraffin wax was added while the mixture was still hot. The amount of paraffin wax added accounted for 3.5% of the total mass of the hydrophilic modified polystyrene. The mixture was stirred well to obtain hydrophilic modified polystyrene.

[0055] (4) Take 22 parts of hydrophilic modified polystyrene, spray it on the surface of mixture II, and dry it to obtain phosphogypsum building material particles.

[0056] Example 3

[0057] (1) Take 420 parts of phosphogypsum, 12 parts of fluorine-containing nano-TiO2 and 20 parts of steel carbon fiber by weight, and stir at 800 r / min for 35 min to obtain mixture I;

[0058] (2) Add 3 parts cellulose ether, 4.5 parts polyethylene glycol, 6.5 parts white cement and 1.5 parts P-type gypsum retarder to mixture I, heat to about 60°C, stir at 450 r / min for 10 min, dry and granulate to obtain mixture II;

[0059] (3) Preparation of hydrophilic modified polystyrene: Crosslinked polystyrene and diethanolamine were mixed at a weight ratio of 1:15-22 and heated to 550°C. After the reaction was complete, the reaction product was filtered. The solid obtained by filtration was washed with ethanol and dried to obtain hydrophilic polystyrene.

[0060] Hydrophilic polystyrene was dissolved in N,N-dimethylformamide, and equal amounts of carbon black and graphene were added. The total amount of carbon black and graphene added accounted for 12.7% of the mass of hydrophilic polystyrene. The mixture was heated and stirred continuously for 6 hours. Then, paraffin wax was added while the mixture was still hot. The amount of paraffin wax added accounted for 6% of the total mass of the hydrophilic modified polystyrene. The mixture was stirred until homogeneous to obtain hydrophilic modified polystyrene.

[0061] (4) Take 22 parts of hydrophilic modified polystyrene, spray it on the surface of mixture II, and dry it to obtain phosphogypsum building material particles.

[0062] <Comparative Example>

[0063] Comparative Example 1

[0064] Take 400 parts by weight of phosphogypsum, 4 parts of polystyrene granules, 0.3 parts of retarder, 3 parts of cellulose ether and 2 parts of polyethylene glycol, mix them, and stir for 40 minutes at 450 r / min speed and 80℃ to obtain phosphogypsum wall material.

[0065] <Experimental Example>

[0066] Samples 1-4: Examples 1-3, Comparative Example 1

[0067] Using the above samples, the mixture was combined with concrete at a total ratio of 1:1.2, and wall panels were fabricated by either application or pouring. A humidifier and a heater were placed approximately 2 meters away from the wall to simulate a rapid damage environment under normal use. The heater temperature was controlled at approximately 28°C. After approximately four weeks of observation and measurement, the wall damage was compared.

[0068] 1. Apply to the surface of the brick wall

[0069] The phosphogypsum samples 1-4 were applied to the surfaces of cement walls and brick walls respectively by smearing. After about 4 weeks, the condition of the walls was observed, and the results are shown in Table 1 below:

[0070] Table 1. Wall conditions coated with different phosphogypsum materials

[0071]

[0072] Among them, "no cracking" means that more than 95% of the wall surface area is free of cracks, "slight cracking" means that about 75-95% of the wall surface area is cracked; "no expansion" means that more than 95% of the wall surface area is free of expansion or even peeling; "slight expansion" means that about 75-95% of the wall surface area is expanded or peeling; "expansion and peeling" means that about 50% or more of the wall surface is expanded and peeling off in patches.

[0073] The comparison shows that the phosphogypsum building material obtained by the technical means of the present invention can maintain long-term stability and waterproof and moisture-proof properties when it is sprayed as a coating on the surface of cement or brick walls.

[0074] 2. Construct an arched wall (in contrast to a rectangular wall).

[0075] The phosphogypsum samples 1-4 were used to construct rectangular and arched walls, respectively, through casting. After approximately four weeks, the wall conditions were observed, and the results are summarized in Table 2 below.

[0076] Table 2. Application of the technology to walls of different shapes

[0077]

[0078] Among them, "no cracking" means that more than 95% of the wall surface area is free of cracks; "minor cracking" means that about 75-95% of the wall surface area is cracked; "cracked and damaged" means that more than 40% of the wall surface area has visible cracks; "no expansion" means that more than 95% of the wall surface area is free of expansion or even peeling; "minor expansion" means that about 75-95% of the wall surface area is expanded or peeling; "expanded and peeling" means that about 50% or more of the wall surface is expanded and peeling off in patches.

[0079] The comparison shows that the phosphogypsum building material obtained by the technical means of the present invention can maintain relatively good structural stability, whether it is cast into a rectangular wall or an irregular wall.

[0080] In summary, the phosphogypsum building material and its preparation method proposed in this invention can solve the problems of poor material stability of existing phosphogypsum, which makes it unsuitable for use in brick walls, irregular walls, and other common applications. It has stronger structural stability and waterproof and moisture-proof properties.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a phosphogypsum building material, characterized by, It comprises the following steps: S1. Take phosphogypsum, fluorine-containing nano-TiO2, rigid fiber, stir and mix uniformly to obtain mixture I; S2. Add white cement, cellulose ether, polyethylene glycol, and retarder to the mixture I, stir and mix uniformly, granulate to obtain mixture II; S3. Prepare hydrophilic modified polystyrene, spray the hydrophilic modified polystyrene on the surface of the mixture II, and control the thickness of the hydrophilic modified polystyrene to be 40-65% of the particle size of the mixture II during spraying, and dry to obtain phosphogypsum building material particles; Among them, by weight, it comprises phosphogypsum 400-450 parts, hydrophilic modified polystyrene 12-35 parts, fluorine-containing nano-TiO2 10-20 parts, rigid fiber 10-25 parts, white cement 3-10 parts, cellulose ether 2-10 parts, polyethylene glycol 2-10 parts, and retarder 0.5-5 parts; The preparation method of the hydrophilic modified polystyrene comprises the following steps: A1. Mix cross-linked polystyrene with organic base, heat, and separate to obtain hydrophilic polystyrene; A2. Dissolve the hydrophilic polystyrene in a solvent, add carbon black and / or graphene, heat, continuously stir, add paraffin while hot, mix uniformly to obtain hydrophilic modified polystyrene.

2. The method of claim 1, wherein the phosphogypsum building material is prepared by mixing phosphogypsum, a binder, and water, and then drying the mixture. The fluorine-containing nano-TiO2 is obtained by introducing fluorine monomer into TiO2 nanoparticles through in-situ compounding.

3. The method of claim 1, wherein the phosphogypsum building material is prepared by mixing phosphogypsum, a binder, and water, and then drying the mixture. In step A1, the weight ratio of cross-linked polystyrene to organic base is controlled to be 1:15-22.

4. The method for preparing the phosphogypsum building material according to claim 3, characterized in that, In step A2, the mass of added carbon black and / or graphene accounts for 12-25% of the mass of hydrophilic polystyrene, and the mass of added paraffin accounts for 3-10% of the total mass of hydrophilic modified polystyrene.

5. The method of claim 1, wherein the phosphogypsum building material is prepared by mixing phosphogypsum, a binder, and water. In step A1, the heating temperature is 40-80℃; in step A2, the heating temperature is 80-100℃.

6. A phosphogypsum building material prepared by the preparation method of any one of claims 1 to 5.

7. A wallboard prepared from the phosphogypsum building material of claim 6.

8. The method of claim 7, wherein the wallboard is prepared by the steps of: Mix the phosphogypsum building material with concrete, and cast to form a wallboard.

9. The method of claim 8, wherein When the phosphogypsum building material is mixed with concrete, the mass of the phosphogypsum building material accounts for 30-60% of the total material mass.

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