Method for slip casting with waste ceramic and then demolding without firing

Abstract

Provided is a method for slip casting with waste ceramic and then demolding without firing. The method comprises: firstly, uniformly mixing and stirring gypsum powder, water, a porous filler, sepiolite fibers, a waterborne epoxy resin, and tributyl phosphate in proportion to prepare a gypsum slurry for preparing a gypsum mold; then uniformly mixing and stirring treated ceramic waste, kaolin, water, a toughening agent, a dispersing agent, a binder, cement, and a curing crystal AB agent in proportion to prepare a slurry; finally pouring the slurry into the gypsum mold, such that the slurry is in full contact with an inner wall of the gypsum mold, and when the slurry is adsorbed to a desired thickness, pouring the redundant slurry out of the gypsum mold; after standing for a certain time, taking out a product blank from the gypsum mold; and finishing and drying the product blank to obtain a molded product. The prepared gypsum mold has good strength and water absorption performance, and the blank obtained by means of slip casting of the slurry in the gypsum mold exhibits good strength and is easy to demold.

Description

A method for demolding and firing waste ceramics after slurry casting. Technical Field

[0001] This invention relates to the field of slip casting technology, and more specifically, to a method for demolding and firing without firing after slip casting using waste ceramics. Background Technology

[0002] Slip casting, also known as casting, is based on the physical property of porous plaster molds that can absorb water. Ceramic powder is mixed into a fluid slurry and then injected into a porous mold (mainly a plaster mold). After the water is absorbed by the mold (plaster mold), a uniform mud layer of a certain thickness is formed. During the dehydration and drying process, a green body with a certain strength is formed. This method is called slip casting.

[0003] Existing single-hole slurry casting methods use molds of specific shapes made of plaster. Kaolin slurry with a water ratio of approximately 1:1 is injected. The dry plaster mold absorbs water from the slurry, causing the kaolin to crystallize and naturally adhere evenly to the inner wall of the mold. Once the crystallized kaolin reaches the desired thickness, the excess slurry is poured out. The crystallization process takes approximately fifteen minutes to an hour. After drying for a certain period, the clay layer inside the mold forms a ceramic blank with a certain strength, which is then removed. Since the quality of the slurry-cast ceramic blank depends on the mold and the slurry, this invention proposes a method for demolding and eliminating the need for firing after slurry casting using waste ceramic.

[0004] Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for demolding and firing without firing after casting waste ceramics, so as to overcome the defects in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for demolding and firing without firing waste ceramics after slurry casting, the method comprising the following steps:

[0007] Step 1) Prepare the plaster mold;

[0008] Gypsum powder, water, porous filler, sepiolite fiber, water-based epoxy resin, and tributyl phosphate are mixed and stirred evenly to prepare gypsum slurry; after filtration, it is poured into shape according to the product and dried to obtain gypsum mold.

[0009] Step 2), Prepare mud;

[0010] Mix the treated ceramic waste, kaolin, water, toughening agent, dispersant, binder, cement, and curing crystal AB agent in the specified proportions until homogeneous, and prepare a slurry.

[0011] Step 3) Grouting and molding;

[0012] After assembling the plaster mold obtained in step 1), bind it tightly with an oil core tape or rubber tape. Then, pour the slurry obtained in step 2) into the plaster mold, ensuring that the slurry fully contacts the inner wall of the plaster mold and is absorbed to the required thickness. Pour out the excess slurry from the plaster mold. After standing for a certain period of time, remove the product blank from the plaster mold. Refine and dry the product blank to obtain the molded product.

[0013] By adopting the above technical solutions, the porous filler added to the prepared gypsum mold can improve the strength and water absorption performance of the gypsum mold; the added sepiolite fiber, uniformly mixed with gypsum powder and porous filler, further increases the strength of the gypsum mold; the added water-based epoxy resin can form an isolation layer on the surface of the porous filler, without affecting the water absorption of the gypsum mold, and the mud layer formed is separated from the gypsum mold after molding, making the molded green body easy to demold; the added tributyl phosphate acts as a defoamer to remove excess air bubbles in the gypsum slurry. The toughening agent added to the prepared slurry, after being uniformly mixed with ceramic waste, kaolin, and cement, can increase the strength of the molded green body; the added dispersant improves the fluidity of the slurry, allowing the ceramic waste and toughening agent to be uniformly suspended in the solution and forming a uniform mud layer on the gypsum mold, making the molded green body easy to demold; the added curing crystal AB agent and binder can firmly bind the toughening agent, ceramic waste, kaolin, and cement together, increasing the strength of the molded green body. Therefore, the resulting plaster mold has good strength and water absorption properties, and the blank obtained by casting the prepared slurry into the plaster mold has good strength and is easy to demold.

[0014] As a further explanation of the method of using waste ceramic grouting for molding and then demolding without firing as described in this invention, preferably, the gypsum mold comprises the following raw materials in parts by weight: 90-100 parts gypsum powder, 55-70 parts water, 5-8 parts porous filler, 0.5-1 part sepiolite fiber, 0.3-0.5 parts waterborne epoxy resin, and 0.1-0.3 parts tributyl phosphate.

[0015] As a further explanation of the method of using waste ceramics for grouting and molding followed by demolding and firing without firing according to the present invention, preferably, the slurry comprises the following raw materials in parts by weight: 80-100 parts of ceramic waste, 30-40 parts of kaolin, 100-130 parts of water, 15-25 parts of toughening agent, 1-3 parts of dispersant and binder, 10-15 parts of cement, and 15-35 parts of curing crystal AB agent.

[0016] As a further explanation of the method of demolding and firing without firing after casting using waste ceramics as described in this invention, preferably, the porous filler is selected from one or more of zeolite powder, bentonite, kaolin and diatomaceous earth.

[0017] As a further explanation of the method of using waste ceramics for grouting and molding followed by demolding and firing without firing, as described in this invention, preferably, the binder includes sepiolite powder, sodium hexametaphosphate, one or more selected from sodium carboxymethyl cellulose, aminocarboxymethyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, polyethylene oxide, polyacrylamide, and polyvinylpyrrolidone.

[0018] As a further explanation of the method for demolding and firing without firing after casting using waste ceramics according to the present invention, preferably, the dispersant is sodium tripolyphosphate and / or sodium polyacrylate.

[0019] As a further explanation of the method of using waste ceramics for grouting and molding followed by demolding and firing without firing, as described in this invention, preferably, the toughening agent is sepiolite fiber.

[0020] As a further explanation of the method of using waste ceramics for slurry casting and demolding without firing as described in this invention, preferably, in step 2), before preparing the slurry, the ceramic waste is acid-washed. The acid-washing treatment uses acetic acid with a concentration of 10%-20%, and after drying, it is passed through a 150-200 mesh sieve.

[0021] By adopting the above technical solution, adding acetic acid with a mass concentration of 10% to pickle ceramic waste can remove the oxide film on the surface of ceramic waste. After drying and sieving, solid powder is obtained, which improves the bonding force between ceramic waste and other components.

[0022] As a further explanation of the method of using waste ceramics for slurry casting and demolding without firing described in this invention, preferably, in step 3), before injecting the slurry, the slurry is subjected to water bath heating treatment at a temperature of 35-40℃.

[0023] By adopting the above technical solution, the viscosity of the slurry is reduced by heating, the permeability of the green body is increased, and the molding time can be accelerated. Inspiration from existing technologies shows that the thickness of the mud layer formed on the green body is proportional to the square root of the molding time.

[0024] As a further explanation of the method for demolding and firing without firing after casting using waste ceramic slurry according to the present invention, preferably, the porosity of the porous filler is 60-70%. More preferably, the particle size of the porous filler is 100-150 μm.

[0025] By adopting the above technical solution, in order to improve the strength and water absorption of the plaster mold, the porosity of the added porous filler is 60-70%, more preferably 65%.

[0026] The beneficial effects of this invention are as follows: The method of this invention prepares a gypsum mold from gypsum powder, water, porous filler, sepiolite fiber, waterborne epoxy resin, and tributyl phosphate. The porous filler added to the prepared gypsum mold can improve the strength and water absorption performance of the gypsum mold; the added sepiolite fiber, when uniformly mixed with gypsum powder and porous filler, further increases the strength of the gypsum mold; the added waterborne epoxy resin can form an isolation layer on the surface of the porous filler, which does not affect the water absorption of the gypsum mold, and the mud layer formed is separated from the gypsum mold after being molded into a blank, making the molded blank easy to demold; the added tributyl phosphate acts as a defoamer to remove excess air bubbles in the gypsum slurry.

[0027] The method of this invention prepares a slurry from ceramic waste, water, sepiolite fiber, sodium tripolyphosphate, and sodium polyacrylate. The toughening agent added to the prepared slurry, when uniformly mixed with ceramic waste, kaolin, and cement, increases the strength of the molded green body. The added dispersant improves the slurry's fluidity, allowing the ceramic waste and toughening agent to be uniformly suspended in the solution, forming a uniform mud layer on the plaster mold, making the molded green body easy to demold. The added curing crystal AB agent and binder firmly bind the toughening agent, ceramic waste, kaolin, and cement together, further increasing the strength of the molded green body.

[0028] Therefore, the plaster mold prepared by the method of the present invention has good strength and water absorption properties, and the blank obtained by casting the prepared slurry into the plaster mold has good strength and is easy to demold. Detailed Implementation

[0029] To further understand the structure, features and other objectives of the present invention, the following detailed description is provided in conjunction with the accompanying preferred embodiments. The described embodiments are only for illustrating the technical solutions of the present invention and are not intended to limit the present invention.

[0030] Preparation of experimental materials:

[0031] Ceramic waste can be collected from various ceramic factories.

[0032] The gypsum powder was purchased from Shandong Xinding Biotechnology Co., Ltd.

[0033] Zeolite powder, bentonite, kaolin, diatomite, and sepiolite fiber were all purchased from Lingshou County Huimao Mineral Products Processing Plant.

[0034] The waterborne epoxy resin was purchased from Shandong Jingshun Chemical Co., Ltd.

[0035] Tributyl phosphate was purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0036] Sodium tripolyphosphate was purchased from Weifang Pengchuang Chemical Co., Ltd.

[0037] Sodium polyacrylate was purchased from Renqiu Pengyu Chemical Co., Ltd.

[0038] Sepiolite powder was purchased from Hebei Xinxu Mineral Products Co., Ltd.

[0039] Sodium hexametaphosphate was purchased from Qingzhou Linghang Chemical Co., Ltd.

[0040] Sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, and polyethylene oxide were purchased from Weifang Shuoyuan Boyue New Material Co., Ltd.

[0041] Aminocarboxymethyl cellulose was purchased from Changhong Cellulose Factory in Wen'an County.

[0042] Ethyl cellulose was purchased from Shandong Weifang Lite Composite Materials Co., Ltd.

[0043] The polyacrylamide was purchased from Henan Saike Environmental Protection Technology Co., Ltd.

[0044] Polyvinylpyrrolidone was purchased from Jinan Tiantai Chemical Co., Ltd.

[0045] The curing crystal AB agent was purchased from Fujian Global Source Environmental Protection Technology Co., Ltd.; the curing crystal AB agent can also be prepared by referring to the concrete curing agent formula and production process disclosed in the patent document with authorization announcement number CN101955331A.

[0046] Example 1: A method for demolding and firing waste ceramics after slip casting

[0047] Preparation of plaster mold: Mix 900g of plaster powder with an average particle size of 120 mesh, 550g of water, 50g of kaolin with a porosity of 60%, 5g of sepiolite fiber, 3g of water-based epoxy resin, and 1g of tributyl phosphate evenly to prepare a plaster slurry; after filtration, pour it into the product shape and dry it to obtain a plaster mold.

[0048] Preparation of the slurry: First, the ceramic waste is acid-washed using 10% acetic acid, and then dried and passed through a 150-mesh sieve. Then, 800g of the treated ceramic waste, 300g of kaolin, 1000g of water, 150g of sepiolite fiber, 10g of dispersant (including 5g of sodium tripolyphosphate and 5g of sodium polyacrylate), 10g of binder (including 3g of sepiolite powder, 3g of sodium hexametaphosphate, and 4g of sodium carboxymethyl cellulose), 100g of cement, and 150g of curing crystal AB agent are mixed thoroughly to form a slurry.

[0049] Slurry casting: First, the slurry is heated in a water bath to 35℃. Then, the plaster mold is assembled and secured with oil-filled straps or rubber bands. Next, slurry at 35℃ is poured into the plaster mold, ensuring full contact between the slurry and the inner wall of the mold. Once the desired thickness is reached, excess slurry is poured out. Finally, after a certain period of settling, the product blank is removed from the plaster mold, refined, and dried to obtain the finished product. Observation shows that the plaster mold and the blank do not stick together when separated, the blank is easy to demold, has high integrity, and increases the yield rate of the blank.

[0050] Inspired by existing technology, it is known that the thickness of the clay layer formed in the blank is proportional to the square root of the molding time. Therefore, the thickness of the clay layer formed in the plaster mold can be adjusted by reducing or increasing the molding time as needed, and the time from settling and drying to removing the blank can also be adjusted accordingly. In this embodiment, the final thickness of the product blank is 3 mm, and the molding time is 15 minutes.

[0051] The plaster mold prepared by the method of the present invention has good strength and water absorption properties. The blank obtained by casting the prepared slurry into the plaster mold has good strength and is easy to demold.

[0052] Example 2: A method for demolding and firing without firing after casting using waste ceramics.

[0053] Preparation of plaster mold: Mix 950g of plaster powder with an average particle size of 130 mesh, 600g of water, 70g of kaolin with a porosity of 65%, 8g of sepiolite fiber, 4g of water-based epoxy resin, and 2g of tributyl phosphate evenly to prepare a plaster slurry; after filtration, pour the slurry into shape according to the product shape, and dry to obtain a plaster mold.

[0054] Preparation of the slurry: First, the ceramic waste is acid-washed using 15% acetic acid, and then dried and passed through a 180-mesh sieve. Then, 900g of the treated ceramic waste, 350g of kaolin, 1250g of water, 200g of sepiolite fiber, 20g of dispersant (including 10g of sodium tripolyphosphate and 10g of sodium polyacrylate), 20g of binder (including 6g of sepiolite powder, 6g of sodium hexametaphosphate, and 8g of sodium carboxymethyl cellulose), 120g of cement, and 250g of curing crystal AB agent are mixed thoroughly to form a slurry.

[0055] Slurry casting: First, the slurry is heated in a water bath to 38℃. Then, the plaster mold is assembled and secured with oil-filled straps or rubber bands. Next, slurry at 38℃ is poured into the mold, ensuring full contact between the slurry and the inner wall of the mold. Once the desired thickness is reached, excess slurry is poured out. Finally, after a certain period of settling, the product blank is removed from the mold, refined, and dried to obtain the finished product. Observation shows that the plaster mold and the blank do not stick together when separated, the blank is easy to demold, has high integrity, and increases the yield rate of the blank.

[0056] Inspired by existing technology, it is known that the thickness of the clay layer formed in the blank is proportional to the square root of the molding time. Therefore, the thickness of the clay layer formed in the plaster mold can be adjusted by reducing or increasing the molding time as needed, and the time from settling and drying to removing the blank can also be adjusted accordingly. In this embodiment, the final thickness of the product blank is 3 mm, and the molding time is 15 minutes.

[0057] The plaster mold prepared by the method of the present invention has good strength and water absorption properties. The blank obtained by casting the prepared slurry into the plaster mold has good strength and is easy to demold.

[0058] Example 3: A method for demolding and firing waste ceramics after slip casting

[0059] Preparation of plaster mold: Mix 1000g of plaster powder with an average particle size of 140 mesh, 700g of water, 80g of kaolin with a porosity of 70%, 10g of sepiolite fiber, 5g of water-based epoxy resin, and 3g of tributyl phosphate evenly to prepare a plaster slurry; after filtration, cast it into shape according to the product shape, and after drying, obtain the plaster mold.

[0060] Preparation of the slurry: First, the ceramic waste is acid-washed using 20% ​​acetic acid and then dried before being sieved through a 200-mesh sieve. Then, 1000g of the treated ceramic waste, 400g of kaolin, 1300g of water, 250g of sepiolite fiber, 30g of dispersant (including 15g of sodium tripolyphosphate and 15g of sodium polyacrylate), 30g of binder (including 9g of sepiolite powder, 9g of sodium hexametaphosphate, and 12g of sodium carboxymethyl cellulose), 150g of cement, and 350g of curing crystal AB agent are mixed thoroughly to form a slurry.

[0061] Slurry casting: First, the slurry is heated in a water bath to 40℃. Then, the plaster mold is assembled and secured with oil-filled straps or rubber bands. Next, slurry at 40℃ is poured into the plaster mold, ensuring full contact between the slurry and the inner wall of the mold. Once the desired thickness is reached, excess slurry is poured out. Finally, after a certain period of settling, the product blank is removed from the plaster mold, refined, and dried to obtain the molded product. Observation shows that the plaster mold and the blank do not stick together when separated, the blank is easy to demold, has high integrity, and increases the yield rate of the blank.

[0062] Inspired by existing technology, it is known that the thickness of the clay layer formed in the blank is proportional to the square root of the molding time. Therefore, the thickness of the clay layer formed in the plaster mold can be adjusted by reducing or increasing the molding time as needed, and the time from settling and drying to removing the blank can also be adjusted accordingly. In this embodiment, the final thickness of the product blank is 3 mm, and the molding time is 15 minutes.

[0063] The plaster mold prepared by the method of the present invention has good strength and water absorption properties. The blank obtained by casting the prepared slurry into the plaster mold has good strength and is easy to demold.

[0064] Example 4:

[0065] This Example 4 follows the method of Example 2, except that the dispersant used in the mud preparation step is 20g of sodium tripolyphosphate. See Table 1.

[0066] Example 5:

[0067] This Example 5 follows the method of Example 2, except that the dispersant used in the mud preparation step is 20g of sodium polyacrylate. See Table 1.

[0068] Example 6:

[0069] This Example 6 follows the method of Example 2, except that the binder used in the mud preparation step is 20g of sepiolite powder. See Table 1.

[0070] Example 7:

[0071] This embodiment 7 follows the method of embodiment 2, except that the binder used in the mud preparation step is 20g of sodium hexametaphosphate. See Table 1.

[0072] Example 8:

[0073] This embodiment 8 follows the method of embodiment 2, except that the binder used in the mud preparation step is 20g of sodium carboxymethyl cellulose. See Table 1.

[0074] Example 9:

[0075] This Example 9 follows the method of Example 2, except that the binder used in the mud preparation step is 20g of polyethylene oxide. See Table 1.

[0076] Example 10:

[0077] This Example 10 follows the method of Example 2, except that the binder used in the mud preparation step is 20g of polyacrylamide. See Table 1.

[0078] Example 11:

[0079] This Example 11 follows the method of Example 2, except that the binder used in the mud preparation step is 20g of polyvinylpyrrolidone. See Table 1.

[0080] Example 12:

[0081] This embodiment 12 follows the method of embodiment 2, except that the binder in the mud preparation step is 10g of sepiolite powder and 10g of sodium hexametaphosphate. See Table 1.

[0082] Example 13:

[0083] This embodiment 13 follows the method of embodiment 2, except that the binder used in the mud preparation step is 10g of sepiolite powder and 10g of sodium carboxymethyl cellulose. See Table 1.

[0084] Example 14:

[0085] This Example 14 follows the method of Example 2, except that the binder used in the mud preparation step is 10g of sodium carboxymethyl cellulose and 10g of sodium hexametaphosphate. See Table 1. Comparative Example 1:

[0086] This comparative example 1 follows the method of example 2, except that water-based epoxy resin is not added in the plaster mold preparation step. See Table 1.

[0087] Comparative Example 2:

[0088] This comparative example 2 follows the method of example 2, except that kaolin is not added in the plaster mold preparation step. See Table 1.

[0089] Comparative Example 3:

[0090] This comparative example 3 follows the method of example 2, except that sepiolite fibers are not added in the plaster mold preparation step. See Table 1.

[0091] Comparative Example 4:

[0092] This comparative example 4 follows the method of example 2, except that kaolin and sepiolite fibers are not added in the plaster mold preparation step. See Table 1.

[0093] Comparative Example 5:

[0094] This comparative example 5 follows the method of example 2, except that sepiolite fiber is not added in the mud preparation step. See Table 1.

[0095] Comparative Example 6:

[0096] This comparative example 6 follows the method of example 2, except that no dispersant is added in the mud preparation step. See Table 1.

[0097] Comparative Example 7:

[0098] This comparative example 7 follows the method of example 2, except that no binder is added in the mud preparation step. See Table 1.

[0099] Comparative Example 8:

[0100] This comparative example 8 follows the method of example 2, except that no solidifying crystal AB agent is added in the mud preparation step. See Table 1.

[0101] Table 1

[0102] Example 15: Performance Test Experiment:

[0103] 1. Test the performance of the prepared plaster mold:

[0104] The oven-dry strength and water absorption rate of the plaster molds prepared in Examples 1-3 and Comparative Examples 1-4 were tested. The strength of the plaster samples was determined according to GB / T 1640-1992, Test Method for Physical Properties of Plaster Powder for Ceramic Molds. The water absorption rate was determined as follows: After testing the flexural strength, the plaster strip specimen was weighed (M1), then immersed in water (the water level was approximately 1 cm above the top of the plaster specimen), left for 2 hours, removed, and excess water was wiped off the surface of the specimen with a damp cloth. The specimen was then weighed (M2) and the water absorption rate was calculated using the following formula: A = (M2 - M1) / M1 * 100%. The test results are shown in Table 2.

[0105] Table 2

[0106] Combining the data on oven-dry strength and water absorption rate of Examples 1-3 and Comparative Examples 1-4 in Table 2, it can be seen that:

[0107] In Comparative Example 1, the absence of water-based epoxy resin in the plaster mold preparation step resulted in no significant impact on the strength and water absorption of the plaster mold. However, observation revealed that when using the plaster mold prepared in Comparative Example 1 for slip casting, the plaster occasionally adhered to the mold during separation from the green body, making demolding difficult. In contrast, when using the plaster molds prepared in Examples 1-3 for slip casting, demolding was easy. Since water-based epoxy resin can form an isolation layer on the surface of porous fillers without affecting the water absorption of the plaster mold, and the formed mud layer is separated from the plaster mold after molding into a green body, the addition of water-based epoxy resin facilitates demolding of the molded green body.

[0108] In Comparative Example 2, the absence of kaolin in the plaster mold preparation step, and in Comparative Example 3, the absence of sepiolite fiber, both affected the strength and water absorption properties of the plaster mold. In Comparative Example 4, the absence of both kaolin and sepiolite fiber had the greatest impact on the strength and water absorption properties of the plaster mold. Therefore, kaolin can improve the strength and water absorption properties of plaster molds, and sepiolite fiber can also improve them; the synergistic effect of kaolin and sepiolite fiber has a greater impact on the strength and water absorption properties of the plaster mold.

[0109] 2. The effect of toughening agent (sepiolite fiber) on the molding of prepared slurry into green bodies:

[0110] The flexural strength of the slurry-formed billets prepared in Examples 1-3 and Comparative Example 5 was tested using a billet strength tester (FCJMYQ, DPK-500 digital display electric billet flexural strength tester). The test results are shown in Table 3.

[0111] Table 3

[0112] Combining the flexural strength data of Examples 1-3 and Comparative Example 5 in Table 3, it can be seen that in Comparative Example 5, without adding sepiolite fibers in the slurry preparation step, the flexural strength of the formed green body is significantly reduced. Therefore, sepiolite fibers can be added to the slurry to increase the strength of the formed green body.

[0113] 3. Effects of sodium tripolyphosphate and sodium polyacrylate on the properties of the prepared mud:

[0114] Since sodium tripolyphosphate and sodium polyacrylate are both dispersants and also act as water-reducing agents, the water reduction rate and flexural strength of the slurry prepared in Examples 1-5 and Comparative Example 6 were tested. The water reduction rate of the slurry was tested according to GB / T8076-2008 "Concrete Admixtures". The water reduction rate of ceramic slurry refers to the ratio of the difference between the water content of the original ceramic raw materials (i.e., without water-reducing agent) and the water content when water-reducing agent is added, to the original water content, when equal masses of ceramic raw materials are mixed with water to achieve the same viscosity. The flexural strength of the formed green bodies was measured using a green body strength tester (brand: FCJMYQ, DPK-500 digital display electric green body flexural strength tester). The test results are shown in Table 4.

[0115] Table 4

[0116] Combining the flexural strength and water reduction rate data of Examples 1-5 and Comparative Example 6 in Table 4, it can be seen that:

[0117] Compared with Example 6, which did not add dispersants (sodium tripolyphosphate and sodium polyacrylate) in the mud preparation step, the flexural strength and water reduction rate of the formed green body were significantly reduced, with the greatest impact on the water reduction rate.

[0118] Sodium tripolyphosphate and sodium polyacrylate were added in Examples 1-3, while sodium tripolyphosphate was added in Example 4 and sodium polyacrylate was added in Example 5. The flexural strength and water reduction rate of the molded preforms obtained in Examples 4-5 were significantly lower than those of the molded preforms obtained in Examples 1-3.

[0119] In addition, upon observation, Comparative Example 6 occasionally showed that the plaster mold and the plaster mold stuck together or the thickness of the plaster mold was uneven when separating the plaster mold from the blank, making it difficult to demold.

[0120] Therefore, sodium tripolyphosphate and sodium polyacrylate have the effects of increasing water reduction and increasing strength, which can make the molded green body easy to demold.

[0121] 4. Test the effect of binder on the properties of the prepared mud:

[0122] The flexural strength of the slurry-formed billets prepared in Examples 6-14 and Comparative Example 7 was tested. The flexural strength of the formed billets was measured using a billet strength tester (FCJMYQ, DPK-500 digital display electric billet flexural strength tester). The test results are shown in Table 5.

[0123] Table 5

[0124] Combining the flexural strength data from Examples 6-14 and Comparative Example 7 in Table 5, it can be seen that:

[0125] In Comparative Example 7, where no binder was added during the slurry preparation step, the flexural strength of the formed green body was significantly reduced. Therefore, binder can be added to the slurry to increase the strength of the formed green body.

[0126] 5. Test the effect of solidified AB agent on the properties of the prepared mud:

[0127] The flexural strength of the slurry-formed billets prepared in Examples 6-14 and Comparative Example 7 was tested. The flexural strength of the formed billets was measured using a billet strength tester (brand: FCJMYQ, DPK-500 digital display electric billet flexural strength tester). The test results are shown in Table 6.

[0128] Table 6

[0129] Combining the flexural strength data of Examples 1-3 and Comparative Example 8 in Table 6, it can be seen that:

[0130] In Comparative Example 8, where no curing crystal AB agent was added during the slurry preparation step, the flexural strength of the formed green body was significantly reduced. Therefore, the curing crystal AB agent can be added to the slurry to increase the strength of the formed green body.

[0131] It should be stated that the above-described invention content and specific embodiments are intended to demonstrate the practical application of the technical solution provided by this invention and should not be construed as limiting the scope of protection of this invention. Those skilled in the art can make various modifications, equivalent substitutions, or improvements within the spirit and principles of this invention. The scope of protection of this invention is defined by the appended claims.

Claims

1. A method for demolding and firing waste ceramics after slurry casting, characterized in that, The method includes the following steps: Step 1) Prepare the plaster mold; Gypsum powder, water, porous filler, sepiolite fiber, water-based epoxy resin and tributyl phosphate are mixed and stirred evenly to prepare gypsum slurry; after filtration, it is cast into shape according to the product and dried to obtain gypsum mold. Step 2), Prepare mud; Mix the treated ceramic waste, kaolin, water, toughening agent, dispersant, binder, cement, and curing crystal AB agent in the specified proportions to form a slurry. Step 3) Grouting and molding; After assembling the plaster mold obtained in step 1), bind it tightly with an oil core tape or rubber tape. Then, pour the slurry obtained in step 2) into the plaster mold, ensuring that the slurry fully contacts the inner wall of the plaster mold and is absorbed to the required thickness. Pour out the excess slurry from the plaster mold. After standing for a certain period of time, remove the product blank from the plaster mold. Refine and dry the product blank to obtain the molded product.

2. The method as described in claim 1, characterized in that, The plaster mold comprises the following raw materials in parts by weight: 90-100 parts plaster powder, 55-70 parts water, 5-8 parts porous filler, 0.5-1 part sepiolite fiber, 0.3-0.5 parts water-based epoxy resin, and 0.1-0.3 parts tributyl phosphate.

3. The method as described in claim 1, characterized in that, The slurry comprises the following raw materials in parts by weight: 80-100 parts ceramic waste, 30-40 parts kaolin, 100-130 parts water, 15-25 parts toughening agent, 1-3 parts dispersant, 1-3 parts binder, 10-15 parts cement, and 15-35 parts curing crystal AB agent.

4. The method as described in claim 1 or 2, characterized in that, The porous filler is selected from one or more of zeolite powder, bentonite, kaolin and diatomite.

5. The method as described in claim 1 or 3, characterized in that, The binder includes sepiolite powder, sodium hexametaphosphate, and one or more selected from sodium carboxymethyl cellulose, aminocarboxymethyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, polyethylene oxide, polyacrylamide, and polyvinylpyrrolidone.

6. The method as described in claim 1 or 3, characterized in that, The dispersant is sodium tripolyphosphate and / or sodium polyacrylate.

7. The method as described in claim 1 or 3, characterized in that, The toughening agent is sepiolite fiber.

8. The method as described in claim 1, characterized in that, In step 2), before preparing the slurry, the ceramic waste is acid-washed using 10%-20% acetic acid and then dried and passed through a 150-200 mesh sieve.

9. The method as described in claim 1, characterized in that, In step 3), before injecting the mud, the mud is subjected to water bath heating treatment at a temperature of 35-40℃.

10. The method as described in claim 1, characterized in that, The porosity of the porous packing is 60-70%.

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