A method of accelerating the setting of gypsum board and uses thereof

Abstract

The application relates to a gypsum board setting accelerating method and application. The method comprises the following steps: mixing gypsum clinker and water, in-situ hydrating hemihydrate gypsum in the gypsum clinker to generate dihydrate gypsum seeds, obtaining setting accelerating slurry containing the dihydrate gypsum seeds, and adding the setting accelerating slurry into a main mixer of a gypsum board production line and mixing the setting accelerating slurry with gypsum clinker and water in the main mixer for preparing gypsum board slurry. The gypsum board setting accelerating method in the application avoids the negative influence of adding the existing setting accelerator potassium sulfate on the strength of gypsum products, and simplifies the preparation process; the gypsum board setting accelerator can be taken as needed, without the need of performing grinding of the setting accelerator, without the need of setting a grinding device and a storage bin of the setting accelerator in the production device, and without the negative influence of the adding amount of the setting accelerator on the gypsum products.

Description

Technical Field

[0001] This article relates to solid waste utilization technology, in particular to a method for accelerating the coagulation of gypsum board and the resulting gypsum board. Background Technology

[0002] In foreign countries, finely ground gypsum is often used as a setting accelerator, prepared by ball milling the gypsum together with admixtures. Domestically, waste boards or sawn edges are often ground into a fine powder and used as a setting accelerator. This requires grinding equipment, and the prepared accelerator needs to be stored in a silo. Furthermore, to meet the requirements of high-speed production lines, some manufacturers add chemical reagents such as potassium sulfate to reduce the gypsum setting time. In these processes, using waste boards or sawn edges as a setting accelerator requires grinding; using gypsum as a setting accelerator requires drying and grinding; adding chemical reagents such as potassium sulfate reduces the strength of gypsum products; and both using waste boards or sawn edges as a setting accelerator and using finely ground gypsum as a setting accelerator require setting accelerator tanks or silos, which can lead to material blockage, manual feeding, and large floor space requirements. Additionally, ball mill grinding suffers from high energy consumption, limited grinding efficiency, and gypsum sticking to the balls. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of protection of this application.

[0004] This application provides a method for accelerating the setting of gypsum board and the resulting gypsum board. The gypsum board accelerator in this application can be used immediately without grinding, eliminating the need for accelerator grinding equipment and accelerator silos in the production plant. Furthermore, the amount of gypsum board accelerator added has no negative impact on the gypsum products.

[0005] The first aspect of this application provides a method for accelerating the setting of gypsum board, the method comprising: mixing gypsum clinker and water to hydrate hemihydrate gypsum in the gypsum clinker in situ to generate dihydrate gypsum seed crystals, obtaining an accelerating slurry containing dihydrate gypsum seed crystals, adding the accelerating slurry to the main mixer of the gypsum board production line, and mixing it with gypsum clinker and water used in the main mixer for preparing gypsum board slurry.

[0006] In one exemplary embodiment, the in-situ hydration time is the interval from the start of contact between the gypsum clinker and water until it is incorporated into the slurry of the main mixer; Optionally, the in-situ hydration time is 0.5-30 min.

[0007] In one exemplary embodiment, the particle size of the gypsum dihydrate seed crystals is 0.01 μm-10 μm.

[0008] In one exemplary embodiment, the method includes: mixing gypsum clinker and water in a main mixer on a gypsum board production line, then taking out a portion of gypsum slurry from the main mixer or its outlet, placing or circulating it outside the main mixer to obtain the accelerating slurry, and adding it to the mixer or its outlet; or An external mixing tank is added, in which gypsum clinker and water are mixed to obtain the coagulating slurry, which is then transported to the main mixer through pipelines; or The gypsum clinker and water are mixed in the mixing tank to obtain the coagulating slurry, which is then transported through a pipeline to the clean water tank on the gypsum board production line and added to the main mixer together with the clean water in the clean water tank.

[0009] In one exemplary embodiment, the method further includes ultrasonic treatment of one or more of the following materials or equipment: The coagulating slurry outside the main mixer, the main mixer to which the coagulating slurry is added, the slurry between the main mixer and the extrusion molding table, and the slurry between the extrusion molding table and the second-stage cutter.

[0010] In one exemplary embodiment, the method further includes: continuously stirring the water tank before adding the coagulating slurry and water to the main mixer to prevent seed crystals in the coagulating slurry from settling.

[0011] In one exemplary embodiment, the amount of the accelerator added, based on the dry solids content in the accelerator grout, is 0.4%-20% of the mass of gypsum clinker used to prepare the gypsum board slurry; for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%. Wherein, the amount of the accelerator added = (mass of gypsum clinker in the accelerator grout / mass of gypsum clinker used to prepare the gypsum board slurry) × 100%.

[0012] In one exemplary embodiment, the amount of coagulating slurry added is 1% to 16%.

[0013] In one exemplary embodiment, while ensuring the fluidity of the mixture, the gypsum clinker and water in the coagulating slurry can be in any ratio to ensure fluidity.

[0014] In one exemplary embodiment, considering factory construction and setting acceleration effects, the mass ratio of gypsum clinker to water in the setting slurry is 0.5-3 times the standard consistency water-to-gypsum ratio. When the mass ratio of gypsum clinker to water in the setting slurry is 0.5-3 times the standard consistency water-to-gypsum ratio, the mass percentage of hydrated water of crystallization is 5%-12%; while when the mass ratio of gypsum clinker to water is 3-11 times the standard consistency water-to-gypsum ratio, the mass percentage of hydrated water of crystallization is greater than 12%.

[0015] In one exemplary embodiment, the method further includes adding other accelerators to the gypsum board slurry.

[0016] In one exemplary embodiment, the other coagulant is one or more of finely ground gypsum, finely ground waste board, sawing waste, and potassium sulfate.

[0017] The second aspect of this application provides a method for preparing gypsum board, comprising: accelerating the coagulation of gypsum board slurry using the above method, and obtaining the gypsum board after extrusion molding, final setting, cutting, and drying.

[0018] The third aspect of this application provides a gypsum board prepared by the above method.

[0019] The fourth aspect of this application provides a method for preparing a gypsum board accelerator, comprising: mixing gypsum clinker and water, causing the hemihydrate gypsum in the gypsum clinker to hydrate in situ to generate dihydrate gypsum seed crystals, thereby obtaining an accelerator slurry containing dihydrate gypsum seed crystals.

[0020] In one exemplary embodiment, the method further includes: treating the coagulating slurry with ultrasound.

[0021] The fifth aspect of this application provides a gypsum board accelerator prepared by the above method.

[0022] In one exemplary embodiment, while ensuring fluidity, the gypsum clinker and water in the gypsum board accelerator can be any ratio to ensure fluidity; considering factory construction and accelerating effect, the mass ratio of gypsum clinker and water in the gypsum board accelerator is 0.5-3 times the water-gypsum ratio of the standard consistency of gypsum.

[0023] Compared with the prior art, this application has the following technical effects: This application uses gypsum slurry, a mixture of gypsum clinker and water, as a setting accelerator, particularly ultrasonically treated gypsum slurry. The setting and preparation methods are simple, and the setting accelerator is used immediately after preparation, simplifying the process. No additional tanks or silos are needed, nor are grinding and storage equipment required, saving space. Furthermore, the amount of setting accelerator added and used in this application is determined according to production line needs. To meet the demands of ultra-high-speed production, it can also be used in conjunction with existing setting accelerators without negatively impacting the strength of gypsum products. Additionally, using gypsum slurry hydrated to a certain degree or pre-treated with ultrasound as a setting accelerator avoids the problem of chemical residues and potassium sulfate blooming, thus avoiding the negative impact of adding existing potassium sulfate setting accelerators on the strength of gypsum products and facilitating the recycling of gypsum boards.

[0024] Furthermore, compared to existing methods that dissolve finely ground gypsum in water to prepare a coagulant, the coagulant's effectiveness decreases because the nano-sized seed crystals of the finely ground gypsum undergo dissolution-maturation after dissolving in water. In contrast, this application uses hemihydrate gypsum to generate seed crystals in situ, and these seed crystals are used at their highest activity level, significantly improving the coagulant efficiency.

[0025] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. Other advantages of this application can be realized and obtained by means of the embodiments described in the description and the accompanying drawings. Attached Figure Description

[0026] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0027] Figures 1 to 2 The scanning electron microscope image of the coagulant sample in Example 6 when the mixing time of the coagulant and added water was 30 s. Figure 3 The conductivity of the gypsum slurry in Example 7 was measured under three conditions: no ultrasound, 90W ultrasound, and 120W ultrasound. Figure 4 The conductivity of the gypsum slurry in Example 8 was measured under ultrasonic conditions of 90W for 4 minutes and 10 minutes, respectively. Figure 5 The conductivity of the gypsum slurry in Example 8 was measured under ultrasonic conditions of 120W for 4 minutes and 10 minutes. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0029] The present application will be further described in detail below with reference to specific embodiments, but these embodiments should not be construed as limiting the present application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this invention.

[0030] Unless otherwise stated, the raw materials used in this application are all conventional products on the market.

[0031] Example 1 100g of gypsum clinker was added to 55g of room temperature water and mixed evenly to obtain gypsum slurry, which was marked as the blank group; the initial setting time of the blank group was measured. 100g of gypsum clinker was added to 55g of room temperature water and mixed evenly to obtain gypsum slurry. The contact time between the gypsum clinker and water was recorded as T and the timing was started at the initial contact. When T was 7 minutes, 6g of gypsum slurry was taken out as a setting accelerator and added to another 55g of water and stirred to disperse, which was marked as group A. When T was 8 minutes and 50 seconds, 100g of gypsum clinker was added to the water in group A, mixed and the timing was started to determine the initial setting time of group A. 100g of gypsum clinker was added to 55g of room temperature water and mixed evenly to obtain gypsum slurry. When T was 11 min, 6g of gypsum slurry was taken out as a setting accelerator and added to another 55g of water and stirred to disperse, which was marked as group B. When T was 12 min 40s, 100g of clinker was added to the water in group B, and after mixing, its initial setting time was measured. 100g of gypsum clinker was added to 55g of room temperature water and mixed evenly to obtain gypsum slurry. When T was 17min, 6g of gypsum slurry was taken out as a setting accelerator and added to another 55g of water and stirred to disperse, which was marked as group C. When T was 18min15s, 100g of clinker was added to the water in group C, mixed, and its initial setting time was measured. 100g of gypsum clinker was added to 55g of room temperature water and mixed evenly to obtain gypsum slurry. When T was 23min, 6g of gypsum slurry was taken out as a setting accelerator and added to another 55g of water and stirred to disperse, which was marked as group D. When T was 24min34s, 100g of clinker was added to the water in group D, and after mixing, its initial setting time was measured.

[0032] This embodiment uses the knife-scratch method to determine the setting time. The method is as follows: the gypsum clinker is added to water containing a setting accelerator and the timer is started. After stirring for 40 seconds, the mixture is poured into a measuring ring with a diameter of 10 cm and a height of 1 cm, leveled, and then lifted after 50 seconds. If the scratch does not disappear after the blade cuts through the gypsum cake, it is determined to be in the initial setting stage.

[0033] The gypsum clinker used in this embodiment is designated as HY, and the initial setting time of each group of gypsum products is shown in Table 1.

[0034] Table 1

[0035] As shown in Table 1, the water-to-solid ratio for preparing the accelerator is the same as that for the gypsum board slurry. The gypsum board accelerator of this application has a significant accelerating effect on gypsum products. Moreover, the longer the hydration time of the gypsum board accelerator, the more complete the hydration and the better the accelerating effect.

[0036] Example 2: This embodiment studies the effect of the gypsum board setting accelerator of this application on the strength of gypsum. The gypsum clinker used is designated as HY. The specific steps are as follows: Blank group: Weigh 1 kg of HY clinker, add 550 g of water, stir for 1 min 40 s, pour into a plaster block mold, and smooth it 3 times. Dry until completely dry, and test the flexural and compressive strength according to GB / T 9776-2022 "Building Plaster"; Weigh 10g of HY clinker and add 6g of water. Stir for 7 minutes to obtain a gypsum slurry. Add 550g of water to the gypsum slurry and stir for 2 minutes. Then add 1kg of HY clinker and stir for 1 minute and 40 seconds. Pour the mixture into a gypsum block mold and smooth it three times. Bake the gypsum block mold until it is completely dry. Determine the flexural and compressive strength according to GB / T 9776-2022 "Building Gypsum". (Number: 7-10) Weigh 20g of HY clinker and add 12g of water. Stir for 7 minutes to obtain a gypsum slurry. Add 550g of water to the gypsum slurry and stir for 2 minutes. Then add 1kg of HY clinker and stir for 1 minute and 40 seconds. Pour the mixture into a gypsum block mold and smooth it three times. Dry until completely dry and measure its flexural and compressive strength. Number: 7-20; Weigh 40g of HY clinker and add 24g of water. Stir for 7 minutes to obtain a gypsum slurry. Add 550g of water to the gypsum slurry and stir for 2 minutes. Then add 1kg of HY clinker and stir for 1 minute and 40 seconds. Pour the mixture into a gypsum block mold and smooth it three times. Dry until completely dry and measure its flexural and compressive strength. Number: 7-40; Weigh 10g of HY clinker and add 6g of water. Stir for 9 minutes to obtain a gypsum slurry. Add 550g of water to the gypsum slurry and stir for 2 minutes. Then add 1kg of HY clinker and stir for 1 minute and 40 seconds. Pour the mixture into a gypsum block mold and smooth it three times. Dry until completely dry and measure its flexural and compressive strength. Number: 9-10; Weigh 20g of HY clinker and add 12g of water. Stir for 9 minutes to obtain a gypsum slurry. Add 550g of water to the gypsum slurry and stir for 2 minutes. Add 1kg of HY clinker and stir for 1 minute and 40 seconds. Pour the mixture into a gypsum block mold and smooth it three times. Dry until completely dry and measure its flexural and compressive strength. Number: 9-20; Weigh 40g of HY clinker and add 24g of water. Stir for 9 minutes to obtain a gypsum slurry. Add 550g of water to the gypsum slurry and stir for 2 minutes. Then add 1kg of HY clinker and stir for 1 minute and 40 seconds. Pour the mixture into a gypsum block mold and smooth it three times. Dry until completely dry and measure its flexural and compressive strength. Number: 9-40.

[0037] The strength results of the gypsum products measured in each group are shown in Table 2 below.

[0038] Table 2

[0039] Table 2 shows that as the proportion of accelerator added increases, the flexural strength of gypsum blocks remains unaffected, while the compressive strength increases slightly. However, when the same amount of accelerator with different degrees of hydration is added, the flexural and compressive strength of gypsum blocks increases slightly.

[0040] Example 3 This embodiment investigated the effect of dihydrate gypsum powder as a setting accelerator on the strength of gypsum. The gypsum clinker used was designated GC. The specific measurement steps are as follows: Weigh 1 kg of clinker (GC grade) and add 600 g of water. Stir for 1 minute and 30 seconds, then pour into a plaster block mold and smooth the surface three times. Dry to oven dry and test flexural and compressive strength. (Number: Blank) Weigh 50g of dihydrate gypsum powder and mix it with 1kg of GC clinker. Add 600g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength according to GB / T 9776-2022 "Building Gypsum". Number: 5-1; Weigh 50g of dihydrate gypsum powder and mix it with 1kg of GC clinker. Add 630g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength. Number: 5-2; Weigh 100g of dihydrate gypsum powder and mix it with 1kg of GC clinker. Add 600g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength. Number: 10-1; Weigh 100g of dihydrate gypsum powder and mix it with 1kg of GC clinker. Add 660g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength. Number: 10-2; Weigh 150g of dihydrate gypsum powder and mix it with 1kg of GC clinker. Add 600g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength. Number: 15-1; Weigh 150g of dihydrate gypsum powder and mix it with 1kg of GC clinker. Add 690g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength. Number: 15-2; Weigh 200g of gypsum dihydrate powder and mix it with 1kg of GC clinker. Add 600g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength. Number: 20-1; Weigh 200g of dihydrate gypsum powder and mix it with 1kg of GC clinker. Add 720g of water, stir for 1 minute and 30 seconds, pour into a gypsum block mold, smooth it three times, and dry it completely. Determine its flexural and compressive strength. Number: 20-2.

[0041] The results obtained by each group are shown in Table 3 below.

[0042] Table 3

[0043] As shown in Table 3, using dihydrate gypsum powder as a coagulant significantly reduces the compressive and flexural strength of gypsum products.

[0044] Example 4: This embodiment studies the setting effect of the gypsum board accelerator of this application compared with other existing accelerators. The gypsum clinker used is designated GC. The specific steps are as follows: Blank group: 100g of clinker labeled GC was mixed with 60g of water and the setting time was measured. Using potassium sulfate as a coagulant: Mix 1g of potassium sulfate with 100g of clinker labeled GC, add 60g of water and stir, then measure the setting time. Using finely ground sawing waste as a coagulant: Mix 1g of coagulant with 100g of clinker numbered GC, add 60g of water and stir, and measure the setting time. Using finely ground gypsum as a coagulant: 8g of coagulant was mixed with 64.8g of water, and then stirred with 100g of clinker labeled GC. The setting time was then measured. The coagulant of this application is as follows: A amount of GC clinker is mixed with a amount of water, and after a certain mixing time t, a coagulant slurry is obtained; b amount of water is added to it, and after stirring for 1 minute and 30 seconds, B amount of GC clinker is added, and after stirring for 2 minutes, the setting time is measured. The setting time was determined using the knife-scraping method described in Example 1, and the results are shown in Table 4.

[0045] Table 4

[0046] As shown in Table 4, the effect of the gypsum board accelerator in this application is comparable to that of potassium sulfate and gypsum dihydrate as accelerators, and in some cases the accelerator effect is even better than that of potassium sulfate and gypsum dihydrate, such as accelerator 3 and accelerator 5 in this application.

[0047] Using finely ground gypsum (dihydrate gypsum) mixed with water as a coagulant resulted in poor coagulation. When finely ground gypsum (particle size <0.01mm) was added to water, the nano-sized dihydrate gypsum particles underwent a dissolution-maturation phenomenon: small particles dissolved, while large particles grew, leading to a decrease in the number of effective seed crystals, an increase in particle size, and a significant decline in coagulation activity.

[0048] The method of in-situ hydration of hemihydrate gypsum (clinker) with water to generate dihydrate gypsum seed crystals in the early stage of hydration results in small (nanoscale) dihydrate gypsum seed crystals with many crystal surface defects and abundant active sites. Since they have not undergone a dissolution-cooking process, their coagulation activity is much higher than that of mechanically ground seed crystals after water immersion.

[0049] Example 5: In this embodiment, the effect of a 16% gypsum board setting accelerator on the strength of gypsum products was determined. The specific steps are as follows: Weigh 1 kg of GC clinker, add 600 g of water, stir for 1 min 20 s, pour into a plaster block mold, and smooth it 3 times. Dry to oven dry and then test the flexural and compressive strength. Number: Blank; Weigh 160g of GC clinker and add 96g of water. Stir for 4 minutes to obtain a slurry for gypsum board accelerator. Add 600g of water to the gypsum board accelerator slurry and stir for 1 minute and 30 seconds. Then add 1kg of GC clinker and stir for 1 minute and 20 seconds. Pour the mixture into a gypsum block mold and smooth it three times. Dry until completely dry and then test the flexural and compressive strength. Number: 4-160.

[0050] The results are shown in Table 5.

[0051] Table 5

[0052] As shown in Table 5, when the dosage of the gypsum board accelerator in this application is 16%, it has no negative impact on the strength of the gypsum products and even slightly increases the strength. Therefore, it can be inferred that when the dosage of the gypsum board accelerator is less than 16%, it will also have no negative impact.

[0053] Example 6: When the dosage of gypsum board accelerator is 16%, the effect of the mixing time of the accelerator slurry and water on the setting time of gypsum products was determined. The results are shown in Table 6.

[0054] Table 6

[0055] As shown in Table 6, in the laboratory, the method of adding the accelerator slurry to the slurry is to first mix it with water, then add the clinker, mix thoroughly, and then measure the setting time. When the accelerator slurry is mixed with added water, the unhydrated hemihydrate gypsum will continue to hydrate. If the mixing time between the accelerator slurry and added water is too long, the crystal nuclei that play a role in accelerating the setting process will become larger, and the setting effect will be weakened.

[0056] Scanning electron microscopy (SEM) was performed on a sample of the coagulant slurry mixed with added water for 30 seconds. The particle size of the coagulant reached the nanometer level. The results are shown in the figure below. Figures 1 to 2 .

[0057] Example 7 This embodiment investigates the effect of ultrasound on the setting accelerator of gypsum board. The specific steps are as follows: 50g of gypsum clinker (GC grade) was mixed with 400g of deionized water at a stirring rate of 300r / min. The conductivity of the gypsum slurry was measured under three conditions: no ultrasound, 90W ultrasound, and 120W ultrasound. The results are shown in [Figure number missing]. Figure 3 .

[0058] Depend on Figure 3 It can be seen that under the action of ultrasound, the electrical conductivity of gypsum slurry decreases by more than 50% compared with the time without ultrasound; the curing time of 90W ultrasound and 120W ultrasound is basically the same.

[0059] Example 8 This embodiment investigated the effect of ultrasonic time on the setting effect of gypsum board setting accelerator. The specific steps are as follows: 50g of GC clinker was mixed with 400g of deionized water at a stirring rate of 300r / min, and ultrasonicated at 90W for 4min and 10min respectively, without stopping the stirring during the test. The conductivity of the gypsum slurry was measured, and the results are as follows. Figure 4 The slurry was ultrasonicated at 120W for 4 minutes and 10 minutes respectively, with continuous stirring during the test. The conductivity of the slurry was measured, and the results are as follows. Figure 5 .

[0060] Depend on Figures 4 to 5 It can be seen that under the action of ultrasound, the longer the ultrasound time, the faster the gypsum solidifies and the better the setting effect.

[0061] As can be seen from the above embodiments: Example 1 demonstrates that the coagulant slurry formed from gypsum slurry has a coagulant-promoting effect in the preparation of gypsum products; Example 2 demonstrates that the coagulant slurry of this application has no negative impact on gypsum products; Example 3 demonstrates that using gypsum dihydrate powder as a coagulant in large quantities negatively affects the strength of gypsum products; while existing potassium sulfate coagulant also has a negative impact on the strength of gypsum products, and when added in large quantities, the surface of gypsum products will "frost". Example 4 demonstrates that the coagulation effect of the coagulant slurry of this application is the same as that of the coagulation effect of the gypsum dihydrate powder coagulant and potassium sulfate. Furthermore, under the conditions of increasing the addition amount and extending the hydration time, the coagulation effect of this application is superior to that of the gypsum dihydrate powder coagulant and potassium sulfate. Example 5 demonstrates that increasing the actual amount of gypsum paste has no negative impact on the strength of gypsum products; Example 6 demonstrates that the coagulation effect in this application is affected by the degree of gypsum hydration in the coagulator slurry; Examples 7-8 demonstrate that ultrasound can promote coagulation.

[0062] In summary, this application uses gypsum slurry, a mixture of gypsum clinker and water, as a setting accelerator, particularly ultrasonically treated gypsum slurry. The setting and preparation methods are simple, and the setting accelerator is used immediately, simplifying the preparation process. No additional tanks or silos are required, nor are grinding and storage equipment needed, saving space. Furthermore, the amount of gypsum board setting accelerator added and used in this application is based on production line needs. To meet the demands of ultra-high-speed production, it can also be used in conjunction with existing setting accelerators without negatively impacting the strength of gypsum products. Additionally, using gypsum slurry hydrated to a certain degree or pre-treated with ultrasound as a setting accelerator avoids the problem of chemical residues and potassium sulfate blooming, thus avoiding the negative impact of adding existing potassium sulfate setting accelerators on the strength of gypsum products and facilitating the recycling of gypsum boards.

[0063] Furthermore, compared to existing methods that dissolve finely ground gypsum in water to prepare a coagulant, the coagulant's effectiveness decreases because the nano-sized seed crystals of the finely ground gypsum undergo dissolution-maturation after dissolving in water. In contrast, this application uses hemihydrate gypsum to generate seed crystals in situ, and these seed crystals are used at their highest activity level, significantly improving the coagulant efficiency.

[0064] Although embodiments of this application have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make adjustments to the above embodiments within the scope of this application. To make changes, modifications, replacements, and variations.

Claims

1. A method for accelerating the setting of gypsum board, the method comprising: Gypsum clinker and water are mixed to allow the hemihydrate gypsum in the gypsum clinker to hydrate in situ and generate dihydrate gypsum seed crystals, resulting in a coagulating slurry containing dihydrate gypsum seed crystals. The coagulating slurry is then added to the main mixer of the gypsum board production line and mixed with the gypsum clinker and water used in the main mixer for preparing gypsum board slurry.

2. The method according to claim 1, wherein, The in-situ hydration time is 0.5-30 min; and / or The particle size of the gypsum dihydrate seed crystals in the coagulating slurry is 0.01μm-10μm.

3. The method according to claim 1 or 2, wherein, The method includes: After gypsum clinker and water are mixed in the main mixer on the gypsum board production line, a portion of the gypsum slurry is taken out from the main mixer or its outlet, placed outside the main mixer or circulated to obtain the accelerating slurry, which is then added back into the mixer or to its outlet; or An external mixing tank is added, in which gypsum clinker and water are mixed to obtain the coagulating slurry, which is then transported to the main mixer through pipelines; or The gypsum clinker and water are mixed in the mixing tank to obtain the coagulating slurry, which is then transported through a pipeline to the clean water tank on the gypsum board production line and added to the main mixer together with the clean water in the clean water tank.

4. The method according to claim 3, wherein, The method also includes ultrasonic treatment of one or more of the following materials or equipment: The coagulating slurry outside the main mixer, the main mixer to which the coagulating slurry is added, the slurry between the main mixer and the extrusion molding table, and the slurry between the extrusion molding table and the second-stage cutter.

5. The method according to claim 3, wherein, The method further includes continuously stirring the water tank before adding the coagulating slurry and water to the main mixer.

6. The method according to claim 1 or 2, wherein, Based on the dry solids content in the accelerator slurry, the amount of accelerator slurry added is 0.4%-20% of the mass of gypsum clinker used to prepare the gypsum board slurry; Optionally, the amount of coagulating slurry added is 1% to 16%.

7. The method according to claim 1 or 2, wherein, The mass ratio of gypsum clinker to water in the coagulating slurry is 0.5-3 times the water-to-gypsum ratio of the standard consistency of gypsum.

8. The method according to claim 1 or 2, wherein, The method further includes: adding other accelerators to the gypsum board slurry; Optionally, the other coagulant is one or more of finely ground gypsum, finely ground waste board, sawing waste, and potassium sulfate.

9. A method for preparing gypsum board, comprising: The gypsum board is obtained by accelerating the coagulation of the gypsum board slurry using the method described in any one of claims 1 to 8, followed by extrusion molding, final setting, cutting, and drying.

10. A gypsum board prepared by the method of claim 9.

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