apparatus for continuous extrusion of gypsum-based materials and method for preparing gypsum-based materials therefrom

Abstract

This invention discloses a device for continuously extruding gypsum-based materials and a method for preparing gypsum-based materials using the same, belonging to the field of building material preparation technology. The device includes a dry material storage tank, a ring conveyor belt, a water-adding device, a wet material storage tank, and an extruder. The outlet of the dry material storage tank is connected to one end of the ring conveyor belt; the inlet of the wet material storage tank is connected to the other end of the ring conveyor belt; the extruder is connected to the outlet of the wet material storage tank; the water-adding device is located above the top surface of the ring conveyor belt and on the side of the dry material storage tank closer to the wet material storage tank; and a flow limiting device is provided on the outlet of the dry material storage tank. This invention changes the traditional method of mixing gypsum-based materials, allowing the water-added gypsum-based material to enter the extruder within 15 seconds. This solves the problems of existing technologies, such as the difficulty in uniformly mixing gypsum-based materials due to rapid solidification, uneven water content distribution leading to low mechanical parameters of the finished product, and difficulty in cleaning after mixing.

Description

Technical Field

[0001] This invention belongs to the field of building material preparation technology, and specifically relates to an apparatus for continuously extruding gypsum-based materials and a method for preparing gypsum-based materials using the same. Background Technology

[0002] Gypsum building materials mainly include energy-saving hollow blocks, gypsum solid bricks, gypsum fiberboard, and other gypsum products. Other gypsum products mainly include gypsum roofing tiles and wall panels. Gypsum-based materials are the materials used to prepare gypsum building materials, including dry materials and water. Dry materials include gypsum and secondary materials, which include one or more of the following: cement, fly ash, lightweight aggregates, and non-metallic fibers.

[0003] Gypsum, a waste product generated after flue gas desulfurization in power plants, is currently not well utilized. The increasing amount of this waste not only occupies space but also pollutes the environment, becoming a major problem for enterprises. Therefore, the state strongly advocates the comprehensive utilization of chemical gypsum such as industrial waste desulfurization gypsum and phosphogypsum. At the same time, the state has legally prohibited the use of sintered clay solid red bricks as building materials in construction. Currently, brick making using gypsum powder almost always uses other cementitious materials as the main component and gypsum as a supplement, forming a mixed type of solid brick. Adding expensive cement and high-setting raw materials to industrial slag gypsum increases the cost. Some companies have tried producing solid bricks entirely from industrial gypsum, but these attempts failed due to insufficient physical strength or inadequate freeze-thaw testing standards, preventing them from reaching the market. Others mix other cementitious materials with gypsum powder, using a slurry method for molding and then sintering, but this method is too costly and unprofitable.

[0004] Gypsum building materials mainly include energy-saving hollow blocks, gypsum solid bricks, gypsum fiberboard, decorative gypsum strips, high-strength roof tiles, and other gypsum products. While developing new building wall materials, it is necessary to eliminate wall products with low compressive strength, large drying shrinkage, and poor engineering application performance. The production and use of small expanded perlite concrete blocks and sintered clay products should be restricted, especially non-energy-saving wall materials with high heat transfer coefficients. Current gypsum block production is all done using the slurry casting method, a "wet process." Wet production requires a large amount of water; more than 65% water needs to be added to each ton of dry powder to achieve uniform slurry mixing. This is known as wet casting production. After molding, the product still needs to be dried, making it a high-energy-consuming product. Furthermore, its energy-saving effect is poor. Therefore, changes in the surrounding humidity have a fatal impact on the strength of the gypsum block wall.

[0005] Patent CN101172796A discloses a fully dry desulfurized gypsum building material production process, including: (1) using desulfurized gypsum, phosphogypsum or natural gypsum as raw materials, drying and calcining at a temperature of 150℃~250℃ for 20~30 minutes; generating a mixed powder composed of high-strength anhydrous gypsum powder and hemihydrate gypsum powder; and sieving through a 40~80 mesh sieve; (2) adding 10%~ 20% water and 1% to 5% inorganic silicon waterproofing agent are mixed and stirred until they remain in dry powder form after stirring; (3) the dry powder mixed in step (2) is transported into the paving machine, and the paving machine lays the material according to the mold thickness; (4) it is pressed under high pressure and shaped under a pressure of 30-50 kg / cm2 to obtain high-density gypsum building materials, namely desulfurized gypsum hollow blocks, gypsum solid bricks and gypsum fiberboard. Its disadvantage is that only dry powder with 20% water can withstand high pressure and obtain high-density gypsum products; when the aqueous solution is added to 25%, the material will flow under pressure and cannot withstand high pressure. The dry powder pressing alone cannot meet the water requirements for the efficient solidification of gypsum products, resulting in the mechanical parameters of the product not reaching the maximum value. The paving machine lays the material according to the mold thickness and presses it under high pressure. It cannot be produced by extrusion, resulting in low production efficiency.

[0006] Patent CN101138863A discloses a method for producing gypsum building products using an extrusion process. This method consists of three main parts: preparing the gypsum extrudate, selecting an extruder composed of four parts: a mixing section 1, a buffer section 2, an extrusion section 3, and a forming die head 4, and the production process steps. The main process involves adding a small amount of a mixing aqueous solution to a gypsum-based material, extruding it through the extruder, cutting it to specified dimensions via a cutting die head, and then finishing the product. Its disadvantages include the need for a water-adding device 5 at the inlet of the extrusion section 3. Water is added and extrusion occurs immediately. Due to the small space in the extrusion section, it is difficult to ensure uniform mixing of water and powder, resulting in poor heat dissipation and uneven mechanical parameters in the produced product. Furthermore, the production process requires the use of a setting regulator, which is relatively expensive.

[0007] Desulfurization gypsum from thermal power plants, a waste product generated after coal-fired desulfurization, is currently not well utilized. The increasing amount of this waste not only occupies space but also pollutes the environment, thus becoming a problem for enterprises. Therefore, the state strongly advocates the comprehensive utilization of industrial waste desulfurization gypsum, phosphogypsum, and other chemical gypsum. Wang Yongsheng et al.'s article, "Factors Affecting the Initial and Final Setting Time of Desulfurization Gypsum" (China Building Materials Science and Technology, 2017, No. 2), listed the initial and final setting times of desulfurization gypsum from three power plants. The initial setting time of desulfurization gypsum was 1 minute 3 seconds to 1 minute 18 seconds, and the final setting time was 4 minutes to 4 minutes 26 seconds. When dry building materials containing desulfurization gypsum are mixed with water in a mixer, the gypsum rapidly absorbs water during mixing. Excessive localized water absorption forms highly viscous clumps that adhere to the mixer blades, walls, and shaft, accumulating thickly and becoming difficult to clean. Furthermore, the initial and final setting time of desulfurized gypsum after absorbing water is only a few minutes, during which it cannot be thoroughly mixed and transported to the production equipment. Therefore, in existing technologies, a semi-dry process is used to produce continuously extruded desulfurized gypsum building materials. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a device for continuous extrusion of gypsum-based materials and a method for preparing gypsum-based materials using the same. By applying a thin layer of water to the dry gypsum-based material outside the mixer, the device obtains gypsum-based materials with optimal and uniform water application. The uniformly water-applied gypsum-based material is then supplied to the extruder for extrusion in a very short time. This solves the problems in existing technologies, such as difficulty in mixing gypsum-based materials, uneven water content distribution after mixing, resulting in low mechanical parameters of the finished product, and difficulty in cleaning after mixing.

[0009] The technical solution adopted in this invention is as follows.

[0010] A continuously extruded gypsum-based material preparation apparatus includes a dry material storage tank, an annular conveyor belt, a water addition device, a wet material storage tank, and an extruder. The outlet of the dry material storage tank is connected to one end of the annular conveyor belt; the inlet of the wet material storage tank is connected to the other end of the annular conveyor belt; the extruder is connected to the outlet of the wet material storage tank; the water addition device is located above the top surface of the annular conveyor belt and on the side of the dry material storage tank closer to the wet material storage tank; and a flow limiting device is provided on the outlet of the dry material storage tank.

[0011] As a preferred technical solution, one end of the annular conveyor belt is located below the discharge port of the mixed dry material storage box, and the other end of the annular conveyor belt is located above the inlet of the wet material storage box.

[0012] As a preferred technical solution, the annular conveyor belt is installed on the active drive wheel and the passive drive wheel, which are in turn installed on the annular conveyor belt support; the mixed dry material storage box is installed on the mixed dry material storage box support; the wet material storage box is installed on the wet material storage box support; the water adding device is equipped with several nozzles; and the water adding device is installed on the water adding device support.

[0013] As a preferred technical solution, the material of the annular conveyor belt is non-metallic.

[0014] As a preferred technical solution, baffles are provided on both sides of the long side of the top surface of the annular conveyor belt.

[0015] As a preferred technical solution, the flow limiting device includes a baffle plate, which is installed on the side of the discharge port of the mixed dry material storage box near the water addition device, and the bottom surface of the baffle plate does not contact the top surface of the annular conveyor belt; the baffle plate is located between two baffles.

[0016] As a preferred technical solution, the baffle plate is perpendicular to the long side of the top surface of the annular conveyor belt.

[0017] As a preferred technical solution, the baffle plate is connected to the discharge port of the mixed dry material storage box through a height adjustment device.

[0018] A method for preparing gypsum-based materials using any of the above-mentioned continuously extruded gypsum-based material preparation devices, characterized in that the method includes the following steps:

[0019] Step 1: Mix the dry gypsum base material evenly and put it into the mixed dry material storage box. The dry gypsum base material includes calcined gypsum powder.

[0020] Step 2: The dry gypsum-based material enters the top surface of the circular conveyor belt through the outlet of the mixed dry material storage box. As the circular conveyor belt moves, a dry material layer is formed on the top surface of the circular conveyor belt. Water is added to the dry material layer through the water adding device. The dry material after adding water forms a wet material layer and enters the wet material storage box. The wet material in the wet material storage box enters the extruder and is extruded.

[0021] As a preferred technical solution, the time from when the gypsum-based dry material enters the top surface of the annular conveyor belt from the outlet of the mixed dry material storage bin to when it enters the extruder from the top surface of the annular conveyor belt does not exceed 15 seconds. The gypsum-based dry material also includes a second material, which includes one or more of cement, fly ash, lightweight aggregate, and non-metallic fibers.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. No water is applied before the dry gypsum substrate is evenly mixed; water is applied to the thin layer of dry material while it moves on the conveyor belt, and no stirring is performed during the water application process. This solves the shortcomings of the existing technology where the calcined gypsum in the dry material is stirred when it is mixed with water, and the gypsum is easy to stick to the blades, walls, shafts, etc. of the stirring device after hydration, making cleaning difficult and the water application uneven.

[0024] 2. The water supply process is completed on a circular conveyor belt, ensuring uniform heat dissipation.

[0025] 3. By continuously feeding dry gypsum substrate into the mixed dry material storage tank and continuously adding water through the water adding device to form a uniformly watered wet material, the wet material is continuously fed into the extruder, and the entire device can achieve continuous production.

[0026] 4. The amount of water can be precisely controlled by adjusting the water supply device and the conveyor belt feeding speed. The water volume is controllable and the water supply is uniform, resulting in products with good mechanical parameters.

[0027] 5. The time from when the dry gypsum-based material enters the top surface of the circular conveyor belt from the outlet of the mixed dry material storage box to when it enters the extruder from the top surface of the circular conveyor belt does not exceed 15 seconds. The gypsum-based material is fed into the extruder before the calcined gypsum initially sets, resulting in products with good mechanical parameters.

[0028] 6. By precisely controlling the amount of water used, the curing time of finished products made from wet materials can be reduced. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the continuously extruded gypsum-based material preparation device of the present invention.

[0030] Figure 2 yes Figure 1 A magnified view of part B.

[0031] Figure 3 yes Figure 1 A magnified view of part C.

[0032] Figure 4 yes Figure 1 A cross-sectional view along A-A' of the apparatus for preparing continuously extruded gypsum-based materials.

[0033] Figure 5 yes Figure 4 A magnified view of part D.

[0034] Figure 6 This is a schematic diagram of the structure of Embodiment 2 of the continuously extruded gypsum-based material preparation device of the present invention.

[0035] Figure 7 yes Figure 6 A magnified view of part E.

[0036] Figure 8 This is a schematic diagram of the structure of Embodiment 3 of the continuously extruded gypsum-based material preparation device of the present invention.

[0037] Figure 9 yes Figure 8 A magnified view of part F.

[0038] Figure 10 yes Figure 8 A magnified view of part G.

[0039] Figure 11 This is a schematic diagram of the structure of Embodiment 4 of the continuously extruded gypsum-based material preparation device of the present invention.

[0040] Figure 12 yes Figure 11 A magnified view of part H.

[0041] The components include: a mixed dry material storage bin-1; a mixed dry material storage bin outlet-10; a mixed dry material storage bin support-11; a circular conveyor belt-2; the top surface of the circular conveyor belt-20; an active drive wheel-21; a passive drive wheel-22; a circular conveyor belt support-23; a water supply device-3; a nozzle-31; a water supply device support-32; an extruder-4; a wet material storage bin-5; a wet material storage bin inlet-51; a wet material storage bin outlet-52; a wet material storage bin support-53; a baffle-6; a height adjustment device-7; and a blocking plate-8. Detailed Implementation

[0042] The present invention will now be further described in conjunction with the accompanying drawings and embodiments.

[0043] Example 1. As... Figure 1-5 As shown, the apparatus for preparing gypsum-based materials that can be continuously extruded includes a dry material storage tank 1, an annular conveyor belt 2, a water adding device 3, a wet material storage tank 5, and an extruder 4. The discharge port 10 of the dry material storage tank is connected to the left end of the annular conveyor belt 2; the inlet 51 of the wet material storage tank is connected to the right end of the annular conveyor belt 2; the extruder 4 is connected to the discharge port 52 of the wet material storage tank; the water adding device 3 is located above the top surface 20 of the annular conveyor belt and on the side of the dry material storage tank 1 near the wet material storage tank 5; and a flow limiting device is provided on the discharge port 10 of the dry material storage tank.

[0044] One end of the ring conveyor belt 2 is located below the discharge port 10 of the mixed dry material storage box, and the other end of the ring conveyor belt 2 is located above the inlet 51 of the wet material storage box.

[0045] The material of the annular conveyor belt 2 is non-metallic. The non-metallic material is rubber.

[0046] The top surface 20 of the annular conveyor belt is provided with baffles 6 on both sides of its long side.

[0047] The flow limiting device includes a baffle plate 8, which is installed on the side of the outlet 10 of the mixed dry material storage box near the water adding device 3. The bottom surface of the baffle plate 8 does not contact the top surface 20 of the annular conveyor belt. The baffle plate 8 is located between two baffles 6.

[0048] The baffle plate 8 is perpendicular to the long side of the top surface 20 of the annular conveyor belt.

[0049] A method for preparing gypsum-based materials using any of the above-mentioned continuously extruded gypsum-based material preparation devices, characterized in that the method includes the following steps:

[0050] Step 1: Mix the dry gypsum base material evenly and put it into the mixed dry material storage box 1. The dry gypsum base material includes calcined gypsum powder.

[0051] Step 2: The dry gypsum-based material enters the top surface 20 of the annular conveyor belt through the outlet 10 of the mixed dry material storage box. Under the obstruction of the baffle plate 8, as the annular conveyor belt 2 moves clockwise, a dry material layer is formed on the top surface of the annular conveyor belt 2. Water is added to the dry material layer through the water adding device 3. The wet material layer formed by the added water enters the wet material storage box 5 from the right end of the annular conveyor belt 2. The wet material in the wet material storage box 5 enters the extruder 4 and is extruded.

[0052] The time from the discharge port 10 of the mixed dry material entering the top surface 20 of the annular conveyor belt to the entry into the extruder 4 from the top surface 20 of the annular conveyor belt does not exceed 8 seconds. The gypsum-based dry material also includes a second material, which includes cement, fly ash, and glass fiber. The amount of water added is 33% of the total weight of the wet material. The thickness of the dry material layer formed on the annular conveyor belt 2 is 1.5 mm. Using this technical solution, the extruded wall panels can be packaged, transported, and used after 36 hours, greatly reducing the drying time.

[0053] The beneficial effects of this embodiment are as follows:

[0054] 1. No water is applied before the dry gypsum substrate is evenly mixed; water is applied to the thin layer of dry material while it moves on the conveyor belt, and no stirring is performed during the water application process. This solves the shortcomings of the existing technology where the calcined gypsum in the dry material is stirred when it is mixed with water, and the gypsum is easy to stick to the blades, walls, shafts, etc. of the stirring device after hydration, making cleaning difficult and the water application uneven.

[0055] 2. The water supply process is completed on a circular conveyor belt, ensuring uniform heat dissipation.

[0056] 3. By continuously feeding dry gypsum substrate into the mixed dry material storage tank and continuously adding water through the water adding device to form a uniformly watered wet material, the wet material is continuously fed into the extruder, and the entire device can achieve continuous production.

[0057] 4. The amount of water can be precisely controlled by adjusting the water supply device and the conveyor belt feeding speed. The water volume is controllable and the water supply is uniform, resulting in products with good mechanical parameters.

[0058] 5. The time from the discharge port 10 of the mixed dry material into the top surface 20 of the annular conveyor belt to the extruder 4 from the top surface 20 of the annular conveyor belt does not exceed 15 seconds. The gypsum-based material is fed into the extruder before the initial setting of the calcined gypsum, resulting in a product with good mechanical parameters.

[0059] 6. By precisely controlling the amount of water used, the curing time of finished products made from wet materials can be reduced.

[0060] Example 2. (As shown) Figure 6-7 As shown, the baffle plate 8 is connected to the outlet 10 of the mixed dry material storage box via a height adjustment device 7. The height adjustment device 7 controls the distance between the baffle plate 8 and the top surface 20 of the annular conveyor belt, thereby controlling the thickness of the dry material layer formed on the top surface of the annular conveyor belt 2. The conveyor belt 2 is made of polyurethane. The amount of water added is 38% of the total weight of the wet material. 2% of the dry material is non-metallic fiber, and the remainder is a second material. The second material is cement, fly ash, and lightweight aggregate. The non-metallic fibers are polyvinyl alcohol fiber and delanet fiber.

[0061] Example 3. (As shown) Figure 8-10 As shown, this embodiment differs from Embodiment 1 in that: the annular conveyor belt 2 is mounted on the active drive wheel 21 and the passive drive wheel 22, which are mounted on the annular conveyor belt support 23; the mixed dry material storage tank 1 is mounted on the mixed dry material storage tank support 11; the wet material storage tank 5 is mounted on the wet material storage tank support 53; the water adding device 3 is equipped with several nozzles 31; and the water adding device 3 is mounted on the water adding device support 32. The amount of water added is 35% of the total weight of the wet material. 1-5% of the dry material weight is non-metallic fiber, and the remainder is a second material. The second material is cement, fly ash, and lightweight aggregate. The non-metallic fibers include cellulose fiber and glass fiber.

[0062] Example 4. (As shown) Figure 11-12As shown, this embodiment differs from Embodiment 1 in that: the annular conveyor belt 2 is mounted on the active drive wheel 21 and the passive drive wheel 22, which are mounted on the annular conveyor belt support 23; the mixed dry material storage tank 1 is mounted on the mixed dry material storage tank support 11; the wet material storage tank 5 is mounted on the wet material storage tank support 53; the water adding device 3 is equipped with several nozzles 31; and the water adding device 3 is mounted on the water adding device support 32. The amount of water added is 32% of the total weight of the wet material. 5% of the dry material is non-metallic fiber, and the remainder is a second material. The second material is cement, fly ash, and lightweight aggregate. The non-metallic fiber includes polypropylene fiber.

[0063] The embodiments listed above are for understanding the present invention only and are not intended to limit the technical solutions described herein. Those skilled in the art can make various changes or modifications, and all equivalent changes or modifications should be covered within the protection scope of the present invention. Any aspects not detailed in the present invention are well-known to those skilled in the art.

Claims

1. A continuously extrudable gypsum-based material preparation apparatus, characterized in that: It includes a mixed dry material storage tank (1), an annular conveyor belt (2), a water adding device (3), a wet material storage tank (5), and an extruder (4); the discharge port (10) of the mixed dry material storage tank is connected to one end of the annular conveyor belt (2); the inlet (51) of the wet material storage tank is connected to the other end of the annular conveyor belt (2), the extruder (4) is connected to the discharge port (52) of the wet material storage tank, the water adding device (3) is located above the top surface (20) of the annular conveyor belt and is located on the side of the mixed dry material storage tank (1) close to the wet material storage tank (5), and a flow limiting device is provided on the discharge port (10) of the mixed dry material storage tank; The material of the annular conveyor belt (2) is non-metallic; The top surface (20) of the annular conveyor belt is provided with baffles (6) on both sides of the long side. The flow limiting device includes a baffle plate (8), which is installed on the side of the outlet (10) of the mixed dry material storage box near the water adding device (3). The bottom surface of the baffle plate (8) does not contact the top surface (20) of the annular conveyor belt. The baffle plate (8) is located between two baffles (6).

2. The apparatus for preparing gypsum-based materials that can be continuously extruded as described in claim 1, characterized in that: One end of the ring conveyor belt (2) is located below the outlet (10) of the mixed dry material storage box, and the other end of the ring conveyor belt (2) is located above the inlet (51) of the wet material storage box.

3. The apparatus for preparing gypsum-based materials that can be continuously extruded as described in claim 1, characterized in that: The circular conveyor belt (2) is installed on the active drive wheel (21) and the passive drive wheel (22), and the active drive wheel (21) and the passive drive wheel (22) are installed on the circular conveyor belt support (23); the mixed dry material storage box (1) is installed on the mixed dry material storage box support (11); the wet material storage box (5) is installed on the wet material storage box support (53); the water adding device (3) is equipped with several nozzles (31); the water adding device (3) is installed on the water adding device support (32).

4. The apparatus for preparing gypsum-based materials that can be continuously extruded as described in claim 1, characterized in that: The baffle (8) is perpendicular to the long side of the top surface (20) of the annular conveyor belt.

5. The apparatus for preparing gypsum-based materials that can be continuously extruded as described in claim 1, characterized in that: The baffle (8) is connected to the outlet (10) of the mixed dry material storage box via the height adjustment device (7).

6. A method for preparing gypsum-based materials using the continuously extruded gypsum-based material preparation apparatus as described in claim 5, characterized in that, The method includes the following steps: Step 1: Mix the dry gypsum base material evenly and put it into the mixed dry material storage box (1). The dry gypsum base material includes calcined gypsum powder. Step 2: The dry gypsum-based material enters the top surface (20) of the annular conveyor belt through the outlet (10) of the dry material storage box. As the annular conveyor belt (2) moves, a dry material layer is formed on the top surface of the annular conveyor belt (2). Water is added to the dry material layer through the water adding device (3). The wet material layer formed by the added water enters the wet material storage box (5). The wet material in the wet material storage box (5) enters the extruder (4) and is extruded.

7. The method for preparing gypsum-based materials as described in claim 6, characterized in that: The time from when the dry gypsum-based material enters the top surface (20) of the annular conveyor belt from the outlet (10) of the mixed dry material storage box to when it enters the extruder (4) from the top surface (20) of the annular conveyor belt does not exceed 15 seconds.

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