Preparation method of recycled slurry prepared from magnesium oxide ceramic green body waste

Abstract

The invention belongs to the technical field of ceramic green body reuse, and discloses a preparation method of reuse slurry prepared from magnesium oxide ceramic green body waste, which comprises the following steps: crushing the magnesium oxide ceramic green body waste scraped by a scraper in a tape casting process, then mixing with magnesium oxide powder according to a mass ratio of 2.8-3.2: 7, supplementing a solvent, a binder and a dispersant into the mixture, and uniformly mixing to obtain the reuse slurry. The concentration of the binder in the reusing slurry is 3.5-9%, the concentration of the dispersant in the reusing slurry is 0.5-1%, and the solid content of the reusing slurry is 51-61%. According to the preparation method of the reusing slurry, the recovered magnesium oxide ceramic green body waste can be continuously processed and used and has good bending strength.

Description

Technical Field

[0001] The present application relates to the technical field of ceramic green body recycling, and in particular to a method for preparing recycled slurry prepared from magnesium oxide ceramic green body waste. Background Art

[0002] In the production process of ceramic products, the crushed powder is first mixed with the organic plasticizer solution in an appropriate ratio to form a slurry with a certain viscosity. The slurry flows down from the container and is scraped and coated on a special base tape with a certain thickness by a scraper. After drying and curing, the film of the green tape is peeled off from the top. Then, according to the size and shape of the finished product, the green tape is punched, laminated and other processing is required to make a finished blank to be sintered.

[0003] Casting machine refers to a special equipment for making cast film. It adopts high-precision electronic ceramic casting machine, uses magnesium oxide as the main raw material of ceramic casting, first mixes the crushed powder with additives and solvent to make a slurry with a certain viscosity, flows down from the hopper, and is scraped and pressed by a scraper to a certain thickness on the special base belt, and after drying and curing, it is peeled off from the top to become a film of the green embryo belt.

[0004] Generally, the green sheets produced by tape casting are collected at the end of the tape casting machine. When the tape casting green sheets are just produced, they are in the form of long continuous thin strips, and then they are cut into block-shaped sheets of the required size, and then put into the furnace to discharge the binder first, and finally sintered at high temperature into a hard magnesium oxide board.

[0005] The magnesium oxide board made by this method has good high temperature resistance, small deformation after multiple sintering, high bending strength, high hardness, certain porosity and good air permeability. It is generally used for sintering of various other products, such as pressing samples to prevent sample warping during sintering, adding weight to reduce sample expansion, etc. It can also be used as a bracket and interlayer for sintering other samples.

[0006] The so-called green body is the ceramic green body after the casting is completed. When the configured slurry comes out of the casting machine and is made into a green body, that is, the organic solvent is basically all volatilized, and the ceramic slurry is formed. At this time, it needs to be cut according to the required size, or the product will be selected to remove the green body with poor surface properties. At this time, a large amount of scraps or waste materials will be generated. This part of the green body is collectively called recycled green body, that is, magnesium oxide ceramic green body waste.

[0007] Chinese patent application 202410287067.1 discloses a method for recycling cleaning waste liquid of ceramic production equipment and an alumina substrate. The method for recycling cleaning waste liquid of ceramic production equipment comprises the following steps:

[0008] Step 1: The magnetic impurities in the cleaning waste liquid are removed by strong magnet adsorption to obtain non-magnetic slurry;

[0009] Step 2: filtering the non-magnetic slurry through a 500-1000 mesh filter to obtain filter residue and filtrate, and centrifuging the filtrate to obtain recovered material and cleaning liquid;

[0010] Step 3: Mix the recycled material with ceramic raw material powder with a particle size D50 of 0.2 to 0.5 μm in a mass ratio of 1:5 to 10 and then disperse by wet ball milling to obtain a dispersed slurry;

[0011] This solution will recycle the cleaning waste liquid and remove the magnetic impurities in the cleaning waste liquid through strong magnet adsorption, so as to avoid the magnetic impurities on the ceramic production equipment from being mixed into the recycled materials when cleaning the ceramic production equipment, resulting in the performance degradation of the alumina substrate obtained in the subsequent production;

[0012] Further observation of step 3 of the scheme shows that the recovered material needs to be further mixed and dispersed with the ceramic raw material powder;

[0013] However, the mass ratio of recycled materials to ceramic raw material powder in this scheme is 1:5-10;

[0014] It can be seen that the quality of the ceramic raw material powder in this scheme is obviously higher than that of the recycled material;

[0015] Further observation of Comparative Example 3 of this solution shows that when 1.5 kg of recycled material and 3.5 kg of ceramic raw material powder are mixed, the density, bending strength and hardness of the final aluminum oxide substrate are obviously worse than those of Example 1;

[0016] That is, when the mass ratio of recycled materials to ceramic raw materials is 1:2.3, the mechanical properties of the obtained alumina substrate, such as strength and density, are significantly reduced.

[0017] The problem to be solved by this scheme is: how to propose a method for preparing recycled slurry from magnesium oxide ceramic green body waste with high magnesium oxide ceramic green body waste utilization rate. Summary of the invention

[0018] The purpose of the present application is to provide a method for preparing recycled slurry from magnesium oxide ceramic green body waste, wherein the magnesium oxide ceramic green body waste scraped off by a scraper during the casting process is crushed, then mixed with magnesium oxide powder at a mass ratio of 2.8 to 3.2:7, and a solvent, a binder, and a dispersant are added to the mixture to obtain recycled slurry;

[0019] The concentration of the binder in the recycled slurry is 3.5-9%, the concentration of the dispersant in the recycled slurry is 0.5-1%, and the solid content of the recycled slurry is 51-61%.

[0020] Preferably, the amount of the supplemented binder is the amount of the binder in the recycled slurry minus the amount of the binder in the magnesium oxide ceramic green body waste;

[0021] The amount of dispersant added is the amount of dispersant in the recycled slurry minus the amount of dispersant in the MgO ceramic green waste.

[0022] Preferably, the solvent is selected from at least one of acetone and ethanol;

[0023] The binder is selected from at least one of polyvinyl butyral and butyl benzyl phthalate;

[0024] The dispersant is selected from at least one of OP-83, OP-50, OP-13, OP-30 and OP-10.

[0025] Preferably, the solvent is a mixture of acetone and ethanol, and the mass ratio of acetone to ethanol in the mixed solvent is 6 to 7.5:1 to 1.7;

[0026] The binder is a mixture of polyvinyl butyral and butyl benzyl phthalate, and the mass ratio of polyvinyl butyral to butyl benzyl phthalate is 4-5; 3-4;

[0027] The dispersant is OP-83.

[0028] Preferably, the method specifically comprises the following steps:

[0029] Step 1: Calculate the mass of the solvent, binder and dispersant to be added according to the mass ratio of the magnesium oxide ceramic green body waste scraped off by the scraper during the casting process to the magnesium oxide powder of 2.8 to 3.2:7, so that the concentration of the binder in the recycled slurry is 3.5 to 9%, the concentration of the dispersant in the recycled slurry is 0.5 to 1%, and the solid content of the recycled slurry is 51 to 61%;

[0030] Step 2: crushing the magnesium oxide ceramic green body scraped off by the scraper during the casting process, dispersing it in a solvent, and ball milling it to obtain a first slurry;

[0031] Step 3: Add the dispersant, magnesium oxide powder and binder into the first slurry for dispersion and ball milling to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste.

[0032] Preferably, step 3 includes the following sub-steps:

[0033] Step A1: adding a dispersant and magnesium oxide powder to the first slurry in sequence, dispersing and ball milling, to obtain a second slurry;

[0034] Step A2: Add a binder to the second slurry and ball-mill to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste.

[0035] Preferably, in step A2, the binder is added in two times, and step A2 is specifically as follows:

[0036] Adding a binder once into the second slurry and ball milling for 4 to 6 hours, then adding a binder a second time and ball milling for 14 to 18 hours to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste;

[0037] The ratio of the mass of the first input of the binder to the mass of the second input is 1:1.

[0038] The beneficial effects of the present invention are:

[0039] The present invention provides a method for preparing recycled slurry prepared from magnesium oxide ceramic green body waste. The method further optimizes the addition amounts of a binder, a dispersant and a solvent in a subsequent slurry preparation process, thereby making the magnesium oxide ceramic green body waste more evenly dispersed in the slurry, thereby causing the magnesium oxide ceramic green body waste to be closer to the state of the raw material magnesium oxide powder for preparing the green body, so that the slurry can still prepare a ceramic product with good surface quality and excellent bending strength when containing more magnesium oxide ceramic green body waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a macroscopic schematic diagram of the ceramic product obtained in Example 1;

[0041] Figure 2 This is a macroscopic schematic diagram of the ceramic product obtained in Example 2;

[0042] Figure 3 This is an electron microscope image of the ceramic product obtained in Example 1;

[0043] Figure 4 The electron microscope image of the ceramic product obtained in Example 2 DETAILED DESCRIPTION

[0044] In the description of the present invention, it should be noted that, if the specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0045] It should be noted that, since the magnesium oxide ceramic green body waste is the magnesium oxide ceramic green body after tape casting and without fat removal, the magnesium oxide ceramic green body waste contains the dispersant and binder that have not been discharged;

[0046] Furthermore, the amount of the supplemented binder is the amount of the binder in the recycled slurry minus the amount of the binder in the magnesium oxide ceramic green body waste;

[0047] The amount of dispersant added is the amount of dispersant in the recycled slurry minus the amount of dispersant in the magnesium oxide ceramic green body waste;

[0048] As for the specific contents of the dispersant and the binder in the magnesium oxide ceramic green body waste in the embodiments and comparative examples, please refer to the specific description of each embodiment and comparative example;

[0049] Example 1

[0050] It should be noted that the concentration of the dispersant in the magnesium oxide ceramic green body used in this embodiment is 0.8%;

[0051] The concentration of the binder was 6%.

[0052] Step 1: Calculate the mass of the solvent, binder and dispersant to be added according to the mass ratio of the magnesium oxide ceramic green body waste scraped off by the scraper during the casting process to the magnesium oxide powder of 3:7, so that the concentration of the binder in the recycled slurry is 6%, the concentration of the dispersant in the recycled slurry is 0.8%, and the solid content of the recycled slurry is 55%;

[0053] Step 2: The magnesium oxide ceramic green body scraped off by the scraper during the casting process is broken, and placed in a mixed solvent prepared by acetone and ethanol in a mass ratio of 6:1.7, and ball-milled at a speed of 350±50 r / min for 26 hours to obtain a first slurry;

[0054] Step 3:

[0055] Step A1: OP-50 dispersant and magnesium oxide powder with a particle size of 3 μm are sequentially added to the first slurry and ball-milled at a speed of 350±50 r / min for 26 h, and then ground by a basket mill at a speed of 1100±100 r / min for 2 h to obtain a second slurry;

[0056] Step A2: Add butyl benzyl phthalate into the second slurry and ball-mill at a rotation speed of 350±50 r / min for 18 hours to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste.

[0057] Example 2

[0058] It should be noted that the concentration of the dispersant in the magnesium oxide ceramic green body used in this embodiment is 1%;

[0059] The concentration of the binder in the magnesium oxide ceramic green body is 9%.

[0060] Step 1: Calculate the mass of the solvent, binder and dispersant to be added according to the mass ratio of the magnesium oxide ceramic green body waste scraped off by the scraper during the casting process to the magnesium oxide powder of 3.2:7, so that the concentration of the binder in the recycled slurry is 9%, the concentration of the dispersant in the recycled slurry is 1%, and the solid content of the recycled slurry is 61%;

[0061] Step 2: The magnesium oxide ceramic green body scraped off by the scraper during the casting process is crushed and placed in a mixed solvent prepared by acetone and ethanol in a mass ratio of 7.5:1, and ball-milled at a speed of 350±50 r / min for 26 hours to obtain a first slurry;

[0062] Step 3:

[0063] Step A1: OP-13 and magnesium oxide powder with a particle size of 3 μm are sequentially added to the first slurry and ball-milled at a speed of 350±50 r / min for 26 h, and then ground by a basket mill at a speed of 1100±100 r / min for 2 h to obtain a second slurry;

[0064] Step A2: Add butyl benzyl phthalate into the second slurry and ball-mill at a rotation speed of 350±50 r / min for 18 hours to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste.

[0065] Example 3

[0066] It should be noted that the concentration of the dispersant in the magnesium oxide ceramic green body used in this embodiment is 0.5%;

[0067] The concentration of the binder in the magnesium oxide ceramic green body is 3.5%.

[0068] Step 1: Calculate the mass of the solvent, binder and dispersant to be added according to the mass ratio of the magnesium oxide ceramic green body scraped off by the scraper during the casting process to the magnesium oxide powder of 2.8:7, so that the concentration of the binder in the recycled slurry is 3.5%, the concentration of the dispersant in the recycled slurry is 0.5%, and the solid content of the recycled slurry is 51%;

[0069] Step 2: The magnesium oxide ceramic green body scraped off by the scraper during the casting process is broken, and placed in a mixed solvent prepared by acetone and ethanol in a mass ratio of 7:1.4, and ball-milled at a speed of 350±50 r / min for 26 hours to obtain a first slurry;

[0070] Step 3:

[0071] Step A1: OP-13 and magnesium oxide powder with a particle size of 3 μm are sequentially added to the first slurry and ball-milled at a speed of 350±50 r / min for 26 h, and then ground by a basket mill at a speed of 1100±100 r / min for 2 h to obtain a second slurry;

[0072] Step A2: Add butyl benzyl phthalate into the second slurry and ball-mill at a rotation speed of 350±50 r / min for 18 hours to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste.

[0073] Example 4

[0074] It is basically the same as Example 1, except that in step A2, the binder is added twice. Step A2 is specifically as follows:

[0075] Adding a binder once into the second slurry and ball milling at a speed of 350±50 r / min for 4 hours, then adding a binder a second time and ball milling at a speed of 350±50 r / min for 14 hours to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste;

[0076] The ratio of the mass of the first input of the binder to the mass of the second input is 1:1.

[0077] Example 5

[0078] It is basically the same as Example 1, except that in step A2, the binder is added twice. Step A2 is specifically as follows:

[0079] Adding a binder once into the second slurry and ball milling at a speed of 350±50 r / min for 8 hours, then adding a binder a second time and ball milling at a speed of 350±50 r / min for 18 hours to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste;

[0080] The ratio of the mass of the first input of the binder to the mass of the second input is 1:1.

[0081] Example 6

[0082] The method is substantially the same as Example 1, except that OP-83 dispersant is used to replace OP-50 dispersant.

[0083] Example 7

[0084] The method is substantially the same as Example 1, except that polyvinyl butyral is used to replace butyl benzyl phthalate.

[0085] Example 8

[0086] The method is basically the same as Example 1, except that a mixture of polyvinyl butyral and butyl benzyl phthalate is used to replace butyl benzyl phthalate, and the mass ratio of polyvinyl butyral to butyl benzyl phthalate is 4:3.

[0087] Example 9

[0088] The method is basically the same as Example 6, except that a mixture of polyvinyl butyral and butyl benzyl phthalate is used to replace butyl benzyl phthalate, and the mass ratio of polyvinyl butyral to butyl benzyl phthalate is 4:3.

[0089] Comparative Example 1

[0090] The method is basically the same as Example 1, except that the mass ratio of the magnesium oxide ceramic green body waste to the magnesium oxide powder is 1:7.

[0091] Comparative Example 2

[0092] The method is basically the same as Example 1, except that the mass ratio of the magnesium oxide ceramic green body waste to the magnesium oxide powder is 4:7.

[0093] Comparative Example 3

[0094] It is basically the same as Example 1, except that the concentration of the binder in the recycled slurry is 2%, the concentration of the dispersant is 4.8%, and the solid content of the recycled slurry is 55%.

[0095] Comparative Example 4

[0096] It is basically the same as Example 1, except that the concentration of the binder in the recycled slurry is 6.6%, the concentration of the dispersant is 0.2%, and the solid content of the recycled slurry is 55%.

[0097] Performance Testing:

[0098] The recycled slurry obtained in each embodiment and comparative example was made into ceramics, and the surface condition of the ceramics and the bending strength were tested by a bending strength tester. The test results are shown in Table 1:

[0099] Table 1

[0100] Group Bending Strength(Kgf) Group Bending strength(Kgf) Example 1 2.0589 Example 8 2.1002 Example 2 2.0421 Example 9 2.4783 Example 3 2.0372 Comparative Example 1 2.0703 Example 4 2.0570 Comparative Example 2 1.8834 Example 5 2.1248 Comparative Example 3 1.4529 Example 6 2.0763 Comparative Example 4 1.8749 Example 7 2.0507

[0101] Result analysis:

[0102] 1. It can be seen from Table 1 that when Examples 1-3 slightly changed the relevant parameters in the preparation process of the recycled slurry, the flexural strength of Examples 1-3 fluctuated to a certain extent, but the overall fluctuation was small;

[0103] 2. It can be seen from Examples 1 and 4-5 that when the binder is further added in two times, the flexural strength of the finished ceramic product has a slight improvement trend relative to Example 1. It can be seen that adding the binder in two times can improve the mechanical strength of the finished ceramic product to a certain extent. The reason is that in the process of adding the binder at one time, part of the slurry may agglomerate, which in turn leads to an increase in defects inside the subsequently prepared finished ceramic product, thereby leading to a decrease in mechanical strength;

[0104] 3. It can be seen from Examples 1 and 6-8 that when OP-83 dispersant is used to replace OP-50 dispersant in Example 1, or polyvinyl butyral is used to replace butyl benzyl phthalate, and a mixture of polyvinyl butyral and butyl benzyl phthalate is used to replace butyl benzyl phthalate, Examples 6 and 8 have a certain degree of improvement trend relative to Example 1, but the trend is relatively weak;

[0105] Further observation of Example 9 shows that when Example 9 simultaneously uses OP-83 dispersant to replace the OP-50 dispersant in Example 1 and uses polyvinyl butyral and butyl benzyl phthalate in a mass ratio of 4:3 to replace butyl benzyl phthalate, the flexural strength of Example 9 has a significant improvement trend relative to Example 1, Example 6, and Example 8. It can be seen that when OP-83 is used as a dispersant, polyvinyl butyral, and butyl benzyl phthalate are used as binders at the same time, the distribution uniformity of the components inside the slurry is stronger and has good bonding properties, thereby resulting in an improvement in the flexural strength of the ceramic product obtained by subsequent processing;

[0106] 4. It can be seen from Example 1 and Comparative Examples 1-2 that when the amount of magnesium oxide powder is increased in Comparative Example 1, although the flexural strength of the ceramic product is improved, the increase is relatively small, and as the content of magnesium oxide powder increases, it means that the same amount of waste needs to consume more magnesium oxide powder, which also means that the production cost is increasing;

[0107] It can be seen from the comparative example 2 that when the addition amount of magnesium oxide powder is further reduced, the flexural strength of the comparative example 2 shows a significant downward trend relative to the embodiment 1. The reason is that as the proportion of waste increases, the uniformity of the components inside the slurry further decreases, which leads to a decrease in the flexural strength of the ceramic product.

[0108] 5. It can be seen from Example 1 and Comparative Examples 3-4 that when the amount of dispersant added is too large and the amount of binder is too small, the viscosity of the slurry will undoubtedly drop significantly, which will make it difficult to shape the slurry during subsequent processing. Even if the sintering time is increased, the ceramic product obtained in Comparative Example 3 still exhibits poor flexural strength;

[0109] Further observation of Comparative Example 4 shows that when the amount of binder added is too large and the amount of dispersant added is too small, the agglomeration phenomenon in the slurry is serious, which leads to uneven distribution of components and further deterioration of the flexural strength of the ceramic product.

[0110] 6. Further references Figure 1-2 It can be seen that the surface of the ceramic product finally obtained in Example 1-2 is smooth without defects such as concave-convex points and cracks;

[0111] Further observation Figure 3-4It can be seen that the surface of the ceramic product obtained in Example 1-2 is still relatively flat from a microscopic point of view.

[0112] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing recycled slurry from magnesium oxide ceramic green body waste, characterized in that: The magnesium oxide ceramic green body waste scraped off by a scraper during the casting process is crushed, and then mixed with magnesium oxide powder at a mass ratio of 2.8 to 3.2:7, and a solvent, a binder, and a dispersant are added to the mixture to obtain a recycled slurry; The concentration of the binder in the recycled slurry is 3.5-9%, the concentration of the dispersant in the recycled slurry is 0.5-1%, and the solid content of the recycled slurry is 51-61%.

2. The method for preparing recycled slurry from magnesium oxide ceramic green body waste according to claim 1, characterized in that: The amount of binder added is the amount of binder in the recycled slurry minus the amount of binder in the magnesium oxide ceramic green body waste; The amount of dispersant added is the amount of dispersant in the recycled slurry minus the amount of dispersant in the MgO ceramic green body waste.

3. The method for preparing recycled slurry from magnesium oxide ceramic green body waste according to claim 1, characterized in that: The solvent is selected from at least one of acetone and ethanol; The binder is selected from at least one of polyvinyl butyral and butyl benzyl phthalate; The dispersant is selected from at least one of OP-83, OP-50, OP-13, OP-30 and OP-10.

4. The method for preparing recycled slurry from magnesium oxide ceramic green body waste according to claim 1, characterized in that: The solvent is a mixture of acetone and ethanol, and the mass ratio of acetone to ethanol in the mixed solvent is 6-7.5:1-1.7; The binder is a mixture of polyvinyl butyral and butyl benzyl phthalate, and the mass ratio of polyvinyl butyral to butyl benzyl phthalate is 4-5; 3-4; The dispersant is OP-83.

5. The method for preparing recycled slurry from magnesium oxide ceramic green body waste according to claim 1, characterized in that: The specific steps include: Step 1: Calculate the mass of the solvent, binder and dispersant to be added according to the mass ratio of the magnesium oxide ceramic green body waste scraped off by the scraper during the casting process to the magnesium oxide powder of 2.8-3.2:7, so that the concentration of the binder in the recycled slurry is 3.5-9%, the concentration of the dispersant in the recycled slurry is 0.5-1%, and the solid content of the recycled slurry is 51-61%; Step 2: crushing the magnesium oxide ceramic green body scraped off by the scraper during the casting process, dispersing it in a solvent, and ball milling it to obtain a first slurry; Step 3: Add the dispersant, magnesium oxide powder and binder into the first slurry for dispersion and ball milling to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste.

6. The method for preparing recycled slurry from magnesium oxide ceramic green body waste according to claim 5, characterized in that: The step 3 includes the following sub-steps: Step A1: adding a dispersant and magnesium oxide powder to the first slurry in sequence, dispersing and ball milling, to obtain a second slurry; Step A2: Add a binder to the second slurry and ball-mill to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste.

7. The method for preparing recycled slurry from magnesium oxide ceramic green body waste according to claim 6, characterized in that: In the step A2, the binder is added in two times, and the step A2 is specifically as follows: Adding a binder once into the second slurry and ball milling for 4 to 6 hours, then adding a binder a second time and ball milling for 14 to 18 hours to obtain a recycled slurry prepared from magnesium oxide ceramic green body waste; The ratio of the mass of the binder input once to the mass of the binder input twice is 1:1.

Images