A high-strength water-resistant rock wool phosphogypsum wallboard and its preparation method

Abstract

This invention provides a high-strength, water-resistant rock wool phosphogypsum wall panel and its preparation method. The wall panel includes phosphogypsum board and rock wool. The phosphogypsum board is made from the following raw materials in parts by weight: 30-60 parts phosphogypsum, 20-30 parts quicklime, 5-10 parts modified solid epoxy resin, and 0.01-0.1 parts retarder. The amount of water added is 1.5 times the total amount of quicklime and phosphogypsum. The modified solid epoxy resin is a powder obtained by blending and extruding 100 parts of solid epoxy resin E20 or NPES-904 raw material, 20-30 parts of acid anhydride curing agent, 1-3 parts of imidazole curing agent, and 3-5 parts of amphoteric surfactant. The acid anhydride curing agent is phthalic anhydride or tetrahydrophthalic anhydride, the imidazole curing agent is dimethylimidazolium, and the amphoteric surfactant is sodium dodecylbenzenesulfonate. The retarder is citric acid, sodium tripolyphosphate, or sodium hexametaphosphate. The method described in this application produces wall panels with high strength and good water resistance due to the good dispersibility of the powder raw materials.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a high-strength water-resistant rock wool phosphogypsum wallboard and its preparation method. Background Technology

[0002] Phosphogypsum is a large solid waste residue left over from phosphoric acid production. Hemihydrate phosphogypsum, with its good setting properties, is also a good building material and is widely used in the construction industry. Although phosphogypsum has a certain strength after setting, its drawbacks, such as poor water resistance, low wet strength, and susceptibility to alkali reversion upon contact with water, limit the application of gypsum products. Furthermore, the limited strength produced by phosphogypsum alone makes it unsuitable for use in structural building components. Therefore, in practical applications, phosphogypsum is often modified by adding water-resistant and reinforcing agents.

[0003] Epoxy resin is an excellent reinforcing material. Adding epoxy resin to phosphogypsum and allowing it to solidify together results in good comprehensive mechanical properties such as water resistance and high strength (compressive strength > 5 MPa). Traditionally, epoxy resins used as reinforcing agents in phosphogypsum are mostly water-based epoxy resins (such as CYDW-100 and modified E-44 epoxy resin), with the addition of a room-temperature water-based resin curing agent, and then added to the phosphogypsum for room-temperature curing. Waterborne epoxy resin is a colloid dispersed in water after emulsifying oil-based resin. When used for phosphogypsum reinforcement, the acidic nature of phosphogypsum can cause premature demulsification of the waterborne epoxy resin. After demulsification, the waterborne epoxy resin is prone to flocculation, leading to uneven dispersion of the resin and phosphogypsum, thus affecting the stability of the product's performance. Furthermore, the curing agents used in waterborne epoxy resins are mostly room-temperature curing agents. The drawback of room-temperature curing is that temperature changes significantly affect the degree of curing. For example, in winter, the lower temperature often requires a longer curing time, and the degree of resin curing is also affected. In summer, the higher temperature allows for faster resin curing, which may not match the hydration and setting time of the phosphogypsum. These are all factors contributing to the unstable strength of epoxy resin-modified phosphogypsum board products. To overcome the aforementioned defects in the epoxy resin-modified phosphogypsum process, this invention provides a gypsum wall panel with good dispersibility, high strength, and water resistance, and its preparation method. Summary of the Invention

[0004] This application provides a high-strength water-resistant rock wool phosphogypsum wall panel and its preparation method, aiming to overcome the problems of demulsification and mismatch between resin curing and phosphogypsum hydration setting time when water-based resin curing agent is mixed with phosphogypsum, thereby improving the strength and water resistance of the wall panel.

[0005] To solve the above-mentioned technical problems, the technical solution proposed in this application is as follows:

[0006] This invention provides a high-strength, water-resistant rock wool phosphogypsum wall panel, comprising phosphogypsum board and rock wool, wherein the rock wool is sandwiched between two phosphogypsum wall panels to form an ABA structure, and the phosphogypsum board is made from the following raw materials in parts by weight: 30-60 parts phosphogypsum, 20-30 parts quicklime, 5-10 parts modified solid epoxy resin, 0.01-0.1 parts retarder, and the amount of water added is 1.5 times the total amount of quicklime and phosphogypsum;

[0007] The modified solid epoxy resin is a powder obtained by blending and extruding 100 parts of solid epoxy resin E20 or NPES-904 raw material, 20-30 parts of acid anhydride curing agent, 1-3 parts of imidazole curing agent, and 3-5 parts of amphoteric surfactant.

[0008] The anhydride curing agent is phthalic anhydride or tetrahydrophthalic anhydride, the imidazole curing agent is dimethylimidazole, and the amphoteric agent is sodium dodecylbenzenesulfonate.

[0009] The retarder is citric acid, sodium tripolyphosphate, or sodium hexametaphosphate.

[0010] Furthermore, it is made from the following raw materials in parts by weight: 58 parts phosphogypsum, 30 parts quicklime, 10 parts modified solid epoxy resin, 0.1 parts retarder, and the amount of water added is 1.5 times the total amount of quicklime and gypsum.

[0011] On the other hand, this application also claims protection for the above-mentioned method for preparing a high-strength water-resistant rock wool phosphogypsum wallboard, comprising the following steps:

[0012] S1: Preparation method of the modified solid epoxy resin: 100 parts of solid epoxy resin E20 or NPES-904 raw material are mixed with 20-30 parts of acid anhydride curing agent, 1-3 parts of imidazole curing agent, and 3-5 parts of amphoteric surfactant at the melting point temperature and extruded in an extruder. The resin, curing agent and amphoteric surfactant are thoroughly mixed and uniformly, and then crushed and sieved into 800-1000 mesh powder to obtain the modified solid epoxy resin.

[0013] S2: Fix the rock wool in the mold, add phosphogypsum, quicklime, modified solid epoxy resin, retarder and water in proportion and stir evenly, then pour into the mold;

[0014] S3: Install a temperature sensor in the gypsum board mold to monitor the reaction temperature inside the mold. When the temperature rises to the peak and begins to drop, it is determined that the epoxy resin has been cured and can be demolded at this time.

[0015] Furthermore, the melting point of solid epoxy resin E20 is 90℃, and the melting point of solid epoxy resin NPES-904 is 110℃.

[0016] Furthermore, the mold is insulated, and an automated control system is introduced to monitor the product reaction temperature in real time.

[0017] Furthermore, the fact that the temperature begins to drop after reaching its peak indicates that the resin curing and phosphogypsum coagulation reaction have been completed, and the material can be demolded in this state.

[0018] Furthermore, it can be used after demolding and subsequent curing.

[0019] Compared with existing technologies, the present invention provides a high-strength water-resistant rock wool phosphogypsum wallboard and its preparation method, which achieves the following beneficial technical effects:

[0020] The present invention relates to a high-strength, water-resistant rock wool phosphogypsum wall panel and its preparation method. The modified powdered solid epoxy resin is used to avoid demulsification. By adjusting the setting time with a retarder, the resin curing and phosphogypsum hydration and setting are synchronized, thereby providing a gypsum wall panel with good dispersibility, high strength, and water resistance, and its preparation method. Attached Figure Description

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

[0022] Figure 1 The graph shows the relationship between the heat released by the reaction of quicklime and water in an embodiment of the present invention.

[0023] Figure 2 The curing curve of the solid epoxy resin at 90°C is provided in the embodiment of the present invention.

[0024] Figure 3 The curves showing the initial and final setting times of gypsum with different amounts of citric acid retarder added according to the present invention.

[0025] Figure 4 The curing time of the E20 resin of this invention is measured under different amounts of phthalic anhydride and different curing temperatures.

[0026] Figure 5 The curing time of epoxy resin under different amounts of tetrahydrophthalic anhydride and different curing temperatures of E20 resin in this invention is shown.

[0027] Figure 6 The curing time of the NPES-904 resin of the present invention is measured under different amounts of phthalic anhydride and different curing temperatures. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1-6 As shown in the embodiment of this application, a high-strength water-resistant rock wool phosphogypsum wall panel includes phosphogypsum board and rock wool. The rock wool is sandwiched between two phosphogypsum wall panels to form an ABA structure. The phosphogypsum board is made from the following raw materials in parts by weight: 30-60 parts phosphogypsum, 20-30 parts quicklime, 5-10 parts modified solid epoxy resin, 0.01-0.1 parts retarder, and the amount of water added is 1.5 times the total amount of quicklime and phosphogypsum; the modified solid... The epoxy resin is a powder obtained by blending and extruding 100 parts of solid epoxy resin E20 or NPES-904 raw material, 20-30 parts of acid anhydride curing agent, 1-3 parts of imidazole curing agent, and 3-5 parts of amphoteric surfactant; the acid anhydride curing agent is phthalic anhydride or tetrahydrophthalic anhydride, the imidazole curing agent is dimethylimidazolium, and the amphoteric surfactant is sodium dodecylbenzenesulfonate; the retarder is citric acid, sodium tripolyphosphate, or sodium hexametaphosphate.

[0030] Modified solid epoxy resin powder is a form of epoxy resin that exists in powder form. It possesses excellent physical properties and chemical stability, exhibiting good adhesion, chemical corrosion resistance, and environmental friendliness. It is commonly used in coatings, adhesives, and sealants, but its application in phosphogypsum-reinforced materials has not been reported. This invention utilizes the numerous advantages of powdered epoxy resin and the ease with which powders can mix uniformly to achieve the mixing of resin and phosphogypsum. First, the solid epoxy resin is modified to obtain hydrophilicity, making it into a powder form that easily mixes with phosphogypsum. This avoids the defect of premature demulsification of water-based epoxy resin caused by the combination of colloidal epoxy resin and powdered phosphogypsum. Furthermore, the modified solid epoxy resin powder of this application is alkaline, further preventing demulsification.

[0031] The present application discloses a method for preparing a high-strength, water-resistant rock wool phosphogypsum wallboard, comprising the following steps:

[0032] S1: Preparation method of the modified solid epoxy resin: 100 parts of solid epoxy resin E20 or NPES-904 raw material are mixed with 20-30 parts of acid anhydride curing agent, 1-3 parts of imidazole curing agent, and 3-5 parts of amphoteric surfactant at the melting point temperature and extruded in an extruder. The resin, curing agent and surfactant are thoroughly mixed and uniformly, and then crushed and sieved into 800-1000 mesh powder to obtain the modified solid epoxy resin.

[0033] S2: Fix the rock wool in the mold, add phosphogypsum, quicklime, modified solid epoxy resin, retarder and water in proportion and stir evenly, then pour into the mold;

[0034] S3: Install a temperature sensor in the gypsum board mold to monitor the reaction temperature inside the mold. When the temperature rises to its peak and begins to decline, it indicates that the epoxy resin curing is complete, and demolding can proceed. The temperature dropping after reaching its peak indicates that the resin curing and phosphogypsum setting reaction are complete; in this state, the material has set and meets the demolding conditions. After demolding, it can be used after subsequent curing.

[0035] To avoid the impact of room temperature curing (mainly due to the large temperature difference between winter and summer) on the degree of resin curing, a relatively high-temperature curing system is used to achieve resin curing. To obtain better process performance, the heat provided by the reaction of quicklime and water is added to provide the required temperature for resin curing, achieving energy self-sufficiency without consuming other energy sources. To match the curing rate of epoxy resin with the setting time of phosphogypsum, a retarder is used to adjust the setting time of the gypsum for better process performance. Simultaneously, to facilitate the preparation process, the product molding mold requires special treatment. Firstly, the mold is insulated, and secondly, an automated control system is introduced to monitor the product reaction temperature in real time to better control the resin reaction and achieve product stability.

[0036] In this application, the phosphogypsum board comprises 30-60 parts of gypsum, 20-30 parts of quicklime, 5-10 parts of modified solid epoxy resin, and 0.01-0.1 parts of retarder, etc. The amount of water added is 1.5 times the total amount of powder materials (quicklime + gypsum).

[0037] Preparation method of modified solid epoxy resin: 100 parts of solid epoxy resin E20 (melting point 90℃) or NPES-904 (110℃) are mixed at the melting point temperature with 20-30 parts of acid anhydride curing agent (phthalic anhydride or tetrahydrophthalic anhydride), 1-3 parts of imidazole curing agent (dimethylimidazole), and 3-5 parts of amphoteric surfactant (sodium dodecylbenzenesulfonate). The mixture is then extruded in an extruder, ensuring thorough and uniform mixing of the resin, curing agent, and surfactant. The mixture is then pulverized and sieved into 800-1000 mesh powder to obtain the modified solid epoxy resin. At this point, the modified solid epoxy resin has been properly cured and exhibits good hydrophilicity.

[0038] First, rock wool is fixed in a mold, serving as the core layer of the board. Gypsum, quicklime, modified epoxy resin, and water are added in proportion and mixed evenly. The mixture is then poured into the mold using a casting method. The mold is insulated. The quicklime reacts exothermically with water, releasing heat sufficient for the curing of the epoxy resin. Simultaneously, the quicklime also strengthens the phosphogypsum. The phosphogypsum wallboard prepared using this method exhibits high strength and water resistance due to the hydration reaction of the phosphogypsum and the properties of thermosetting resin materials.

[0039] A temperature sensor is installed in the gypsum board mold, and the reaction temperature of the system is monitored by a temperature control system. Since the reaction between quicklime and water is an exothermic reaction, and the resin curing is also an exothermic reaction, the temperature will be superimposed during the system reaction and curing process. The temperature of the reaction system is detected. When the temperature rises to the peak and begins to drop, the epoxy resin curing is complete, and the mold can be demolded.

[0040] The relationship for determining the heat released during the reaction of quicklime and water is shown in [reference needed]. Figure 1 The experiment involved measuring the temperature after adding different amounts of water to a 10g calcium oxide solution. The temperature peaked when 2g of water was added, indicating that the amount of calcium oxide added was significantly more than the theoretical value.

[0041] 2. Resin curing experiment

[0042] The relationship between resin curing temperature and curing time, as measured by the Gelprof 518 resin reaction behavior analyzer, is shown in the figure. Figure 4-6 The following are the test results of resin curing reaction under different formulations and temperatures.

[0043] Table 1 Composite Material Components

[0044]

[0045] Example 1

[0046] Preparation of 80×20×300mm sheet material:

[0047] Preparation method of E20 modified solid epoxy resin: 100 kg of solid epoxy resin E20, 20 kg of phthalic anhydride, and 5 kg of sodium dodecylbenzenesulfonate are extruded through an extruder at 90°C. The resin, curing agent, and activator are thoroughly mixed and homogeneous. The mixture is then pulverized and sieved into 800-mesh powder to obtain the modified solid epoxy resin. At this point, the modified solid epoxy resin has been properly cured and exhibits good hydrophilicity.

[0048] First, rock wool is fixed in a mold, serving as the core layer of the board. 177 kg of hemihydrate phosphogypsum, 90 kg of quicklime, 30 kg of E20 modified solid epoxy resin, 0.0177 kg of citric acid retarder, and 400 kg of water are mixed and poured into the mold, and the reaction temperature is monitored. When the temperature rises to 183 degrees Celsius, it begins to decrease. At this point, the product is demolded to obtain a high-strength, water-resistant board.

[0049] Board test results: Compressive strength 6.8 MPa; Water absorption 3%.

[0050] Example 2

[0051] Preparation of 80×10×300mm sheet material:

[0052] Preparation method of NPES-904 modified solid epoxy resin: 100 kg of solid epoxy resin NPES-904, 15 kg of tetrahydrophthalic anhydride, and 3 kg of sodium dodecylbenzenesulfonate are extruded through an extruder at 110℃. The resin, curing agent, and activator are thoroughly mixed and homogeneous, and then pulverized and sieved into 1000-mesh powder to obtain the modified solid epoxy resin. At this point, the modified solid epoxy resin has been properly cured and has good hydrophilicity.

[0053] First, rock wool is fixed in the mold, serving as the core layer of the board. Then, 102 kg of hemihydrate phosphogypsum, 30 kg of quicklime, 15 kg of NPES-904 modified solid epoxy resin, 0.12 kg of sodium tripolyphosphate retarder, and 282 kg of water are mixed and poured into the mold, and the reaction temperature is monitored. When the temperature rises to 165 degrees Celsius, it begins to decrease. At this point, the product is demolded to obtain a high-strength, water-resistant board.

[0054] Gypsum, quicklime, modified epoxy resin, and water are added and mixed in a specific ratio, then poured into a mold. The mold is insulated. The quicklime reacts exothermically with water, releasing heat sufficient for the curing of the epoxy resin. Simultaneously, the quicklime also strengthens the phosphogypsum. The resulting phosphogypsum wallboard, through the hydration reaction of the phosphogypsum, exhibits the strength of thermosetting resins and possesses high strength and water resistance.

[0055] Board test results: compressive strength 6.1 MPa; water absorption 5%.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength, water-resistant rock wool phosphogypsum wall panel, characterized in that, The product includes phosphogypsum board and rock wool, wherein the rock wool is sandwiched between two phosphogypsum wallboards to form an ABA structure. The phosphogypsum board is made from the following raw materials in parts by weight: 30-60 parts phosphogypsum, 20-30 parts quicklime, 5-10 parts modified solid epoxy resin, 0.01-0.1 parts retarder, and the amount of water added is 1.5 times the total amount of quicklime and phosphogypsum. The modified solid epoxy resin is a powder obtained by blending and extruding 100 parts of solid epoxy resin E20 or NPES-904 raw material, 20-30 parts of acid anhydride curing agent, 1-3 parts of imidazole curing agent, and 3-5 parts of amphoteric surfactant. The anhydride curing agent is phthalic anhydride or tetrahydrophthalic anhydride, the imidazole curing agent is dimethylimidazole, and the amphoteric agent is sodium dodecylbenzenesulfonate. The retarder is citric acid, sodium tripolyphosphate, or sodium hexametaphosphate.

2. The high-strength water-resistant rock wool phosphogypsum wallboard according to claim 1, characterized in that, It is made from the following raw materials in parts by weight: 58 parts phosphogypsum, 30 parts quicklime, 10 parts modified solid epoxy resin, 0.1 parts retarder, and the amount of water added is 1.5 times the total amount of quicklime and gypsum.

3. The method for preparing a high-strength water-resistant rock wool phosphogypsum wallboard according to claim 1, characterized in that, Includes the following steps: S1: Preparation method of the modified solid epoxy resin: 100 parts of solid epoxy resin E20 or NPES-904 raw material are mixed with 20-30 parts of acid anhydride curing agent, 1-3 parts of imidazole curing agent, and 3-5 parts of amphoteric surfactant at the melting point temperature and extruded in an extruder. The resin, curing agent and amphoteric surfactant are thoroughly mixed and uniformly, and then crushed and sieved into 800-1000 mesh powder to obtain the modified solid epoxy resin. S2: Fix the rock wool in the mold, add phosphogypsum, quicklime, modified solid epoxy resin, retarder and water in proportion and stir evenly, then pour into the mold; S3: Install a temperature sensor in the gypsum board mold to monitor the reaction temperature inside the mold. When the temperature rises to the peak and begins to drop, it is determined that the epoxy resin has been cured and can be demolded at this time.

4. The method for preparing a high-strength water-resistant rock wool phosphogypsum wallboard according to claim 3, characterized in that, The melting point of solid epoxy resin E20 is 90℃, and the melting point of solid epoxy resin NPES-904 is 110℃.

5. The method for preparing a high-strength water-resistant rock wool phosphogypsum wallboard according to claim 3, characterized in that, The mold is insulated, and an automated control system is introduced to monitor the reaction temperature of the product in real time.

6. The method for preparing a high-strength water-resistant rock wool phosphogypsum wallboard according to claim 3, characterized in that, After demolding and subsequent curing, it can be used.

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