Recycling method of green body waste in ceramic membrane production process

Abstract

The invention discloses a method for recycling green body waste in a ceramic membrane production process, and relates to the technical field of recycling of inorganic non-metallic materials. The method comprises the following steps: 1, collecting and classifying waste materials; 2, moisture content determination and crushing; 3, vacuum water saturation; 4, pressure dehydration; 5, kneading and vacuum pugging are repeated; 6, evaluating the cohesiveness; the core of the method is that water deeply and uniformly permeates into the dried waste through vacuum water saturation, then the water content is accurately regulated and controlled to the optimal plasticity interval through air pressure dehydration, and finally, thorough homogenization of pug is achieved through repeated kneading and pug refining. According to the method, the technical problem of recycling of the dried green body waste is effectively solved, the obtained regenerated pug is high in quality, high-proportion recycling can be achieved, and economic and environment-friendly benefits are remarkable.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic material recycling technology, specifically to a method for recycling green waste from the ceramic membrane production process. Background Technology

[0002] Ceramic membranes are widely used in separation, filtration, and catalysis due to their excellent chemical stability, thermal stability, and mechanical strength. Typical production processes include: batching, mixing, slurry preparation, extrusion molding, drying, and sintering. In the green body stage after drying, precision machining such as cutting, grinding, and drilling is required to meet product dimensional requirements. This process generates a large amount of dried green body waste. This waste has already undergone drying treatment, with a moisture content far lower than that of the extruded wet green body; it is brittle and hard, and its internal pore structure is basically fixed.

[0003] Currently, the main method for treating this type of dried green body waste is to discard it as industrial solid waste. If it is simply crushed and reused, the significant difference in water absorption rate and speed between the dried green body and the virgin powder or wet clay means that directly adding water will result in extremely uneven moisture distribution, poor plasticity, and difficulty in achieving effective homogenization through subsequent clay refining processes. This easily leads to defects such as cracks and deformation during subsequent molding and sintering, failing to meet the production requirements of high-performance ceramic films. Therefore, the technical challenge in recycling dried green body waste lies in how to restore it to a uniform and suitable moisture content and good plasticity, and to restore its bonding properties.

[0004] Directly discarding or treating these waste materials with low value not only wastes raw materials such as ceramic powder and additives, increasing production costs, but also creates environmental pressure. Therefore, developing an efficient and high-quality recycling method specifically tailored to the characteristics of dried green body waste is of great significance. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a method for recycling green waste in the ceramic membrane production process.

[0006] This invention provides a method specifically for the recycling of ceramic film drying green body waste. This method effectively solves the technical problem that the low moisture content, high brittleness, and difficulty in homogenization of dried green body waste prevent its high-quality reuse, ensuring that the performance of the recycled clay meets the requirements for ceramic film forming.

[0007] A method for recycling green waste from ceramic membrane production includes the following steps:

[0008] I. Waste Collection and Classification:

[0009] Waste generated during the drying process of ceramic film green body is classified and collected according to its basic material to obtain classified waste.

[0010] II. Moisture Content Determination and Crushing:

[0011] The initial moisture content of the sorted waste was determined, and the waste was mechanically crushed. The particle size of the crushed material was controlled to obtain the crushed waste.

[0012] III. Vacuum saturation:

[0013] The crushed waste material is degassed and soaked in water under a continuous negative pressure vacuum environment, so that water penetrates into the interior of the waste particles to obtain water-saturated waste material.

[0014] IV. Pressure Dehydration:

[0015] External air pressure is applied to the saturated waste to remove excess surface moisture and precisely adjust the moisture content of the waste to a plastic state suitable for plucking, thus obtaining dewatered waste.

[0016] V. Repeated kneading and vacuum kneading:

[0017] ① The dehydrated waste material is kneaded and vacuum slurry processed in sequence;

[0018] ② Repeat step 5① to obtain homogenized mud and remove air bubbles to obtain recycled mud;

[0019] VI. Adhesion Evaluation:

[0020] The molding performance of the recycled clay is evaluated, and it can only be reused after it meets the standards, thus obtaining homogenized recycled ceramic membrane clay.

[0021] The beneficial effects of this invention are as follows:

[0022] I. Highly Targeted: This invention is specifically designed to address the characteristics of "dry green waste"—low moisture content, difficulty in wetting, and difficulty in homogenization. It completely solves the water absorption problem through "vacuum saturation" and precisely controls the final moisture content through "air pressure dehydration," resulting in a clear and effective process path.

[0023] II. High quality of recycling: "Vacuum saturation" ensures deep and uniform water penetration; "Air pressure dehydration" ensures uniform pressure and avoids damage to the clay structure; "Repeated kneading and mixing" guarantees the ultimate homogenization effect of the clay; Recycled clay has reliable performance, and the wet brick strength can reach more than 85% of the original material.

[0024] Third, high degree of resource utilization: It realizes the high-value recycling of dried green waste, saves costs, reduces solid waste emissions, and meets the requirements of green manufacturing;

[0025] IV. Good process controllability: Key step parameters are clearly defined, making it easy to achieve process control and quality monitoring. Detailed Implementation

[0026] Specific Implementation Method 1: This implementation method is a method for recycling green waste from the ceramic membrane production process, including the following steps:

[0027] I. Waste Collection and Classification:

[0028] Waste generated during the drying process of ceramic film green body is classified and collected according to its basic material to obtain classified waste.

[0029] II. Moisture Content Determination and Crushing:

[0030] The initial moisture content of the sorted waste is determined (usually very low, for example, <5%) and mechanically crushed (this step aims to increase the specific surface area, which is conducive to uniform water absorption in the later stage). The particle size of the crushed material is controlled to obtain the crushed waste.

[0031] III. Vacuum saturation:

[0032] The crushed waste material is degassed and soaked in water under a continuous negative pressure vacuum environment (deionized water or pure water is injected under continuous negative pressure so that the water can overcome capillary resistance and quickly and evenly penetrate into the pores inside the dried waste material particles. This step is one of the key points of the present invention, which aims to completely change the low moisture state of the dried green blank and lay the foundation for its subsequent plastic processing). Water penetrates into the interior of the waste material particles to obtain water-saturated waste material.

[0033] IV. Pressure Dehydration:

[0034] External air pressure is applied to the saturated waste to remove excess surface moisture and precisely adjust the moisture content of the waste to a plastic state suitable for plucking, thus obtaining dewatered waste.

[0035] V. Repeated kneading and vacuum kneading:

[0036] ① The dehydrated waste material is kneaded and vacuum slurry processed in sequence;

[0037] ② Repeat step 5① to obtain homogenized mud and remove air bubbles to obtain recycled mud;

[0038] VI. Adhesion Evaluation:

[0039] The molding performance of the recycled clay is evaluated, and it can be reused only after it meets the standards (qualified recycled clay can be used for the preparation of ceramic film green bodies) to obtain homogenized recycled ceramic film clay.

[0040] In step four of this embodiment, the external air pressure is provided by an air compressor combined with a pressurized, bottom-draining vacuum sealing device (such as a sealed dewatering tank with an air pressure interface or a diaphragm filter press), with a pressure range of 1MPa to 15MPa. Through uniform and gentle compression by air pressure, free water between material particles and on some of their surfaces is removed, thereby precisely adjusting the overall moisture content from a supersaturated state to a plastic state suitable for plucking (8%-20%). This moisture content range is a specific range for extremely dry waste that has been saturated with water and then dewatered to a point where it has good plasticity.

[0041] In step five of this embodiment, air bubbles are eliminated, density and plasticity are improved; in order to completely eliminate the unevenness that may be caused by the source of waste materials, the "kneading-vacuum kneading" process in step five① above needs to be repeated at least once, preferably 2-3 times, to ensure that the clay is highly homogenized.

[0042] The core of this implementation method is to achieve deep and uniform penetration of moisture into the interior of the dried waste material through "vacuum saturation," then precisely control the moisture content to the optimal plastic range through "air pressure dehydration," and finally achieve thorough homogenization of the mud material through "repeated kneading and mixing." This invention effectively solves the technical problem of recycling dried green waste material, and the resulting recycled mud material is of high quality, can be reused at a high rate, and has significant economic and environmental benefits.

[0043] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the basic materials mentioned in step one include alumina, silicon carbide, silicon dioxide, mullite, and aluminum titanate. The other steps are the same as in Specific Implementation Method One.

[0044] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the mechanical crushing in step two uses a jaw crusher, a double roll crusher, or a shear crusher; the particle size D90 of the crushed material in step two is 0.5~5mm. Other steps are the same as in Specific Implementation Method One or Two.

[0045] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the absolute pressure of the negative pressure vacuum environment described in step two is not higher than -0.08 MPa; the degassing and immersion time in step two is 15 min to 60 min. Other steps are the same as in Specific Implementation Methods One to Three.

[0046] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: the external air pressure mentioned in step four is provided by an air compressor combined with a bottom-venting vacuum sealing device, with a pressure range of 1MPa to 15MPa; the moisture content of the dehydrated waste material mentioned in step four is 8% to 20%. Other steps are the same as in Specific Implementation Methods One to Four.

[0047] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: the kneading process described in step five① is carried out in a twin-shaft kneader, and the kneading time is not less than 10 minutes; the vacuum degree of the vacuum slurry treatment described in step five① is not higher than -0.095 MPa. Other steps are the same as in Specific Implementation Methods One to Five.

[0048] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Methods One to Six is ​​that step Five ① is repeated at least once in step Five ②. The other steps are the same as in Specific Implementation Methods One to Six.

[0049] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step six, the recycled clay material is made into standard-sized test strips, and its flexural strength in the wet state is measured. When this strength value is not less than 85% of the wet strength of the original clay material in the same period, it is judged to be qualified. Other steps are the same as in Specific Implementation Methods One to Seven.

[0050] Specific Implementation Method Nine: This implementation method is a homogenized regenerated ceramic film slurry obtained by any one of Specific Implementation Methods One to Eight.

[0051] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the homogenized recycled ceramic membrane slurry is obtained by extrusion molding, or by mixing the homogenized recycled ceramic membrane slurry with virgin slurry in a certain proportion and then extruding. The other steps are the same as in Specific Implementation Methods One to Nine.

[0052] The beneficial effects of the present invention are verified using the following embodiments:

[0053] Example 1: A method for recycling green waste from ceramic membrane production, comprising the following steps:

[0054] I. Waste Collection and Classification:

[0055] Collect waste materials from the cutting of green bodies dried using the same type of alumina ceramic film;

[0056] II. Moisture Content Determination and Crushing:

[0057] The initial moisture content of the waste was determined to be 1.5%. It was crushed into particles with a D90 of approximately 2 mm using a jaw crusher and a double roll crusher to obtain the crushed waste.

[0058] III. Vacuum saturation:

[0059] The crushed waste material is put into a vacuum saturation tank, vacuumed to -0.085MPa and maintained for 30 minutes, then deionized water is injected until it is completely submerged, and the vacuum state is maintained for 40 minutes to allow water to penetrate into the waste particles, thus obtaining saturated waste material.

[0060] IV. Pressure Dehydration:

[0061] The saturated waste material was transferred to a pneumatic dewatering tank with a filter cloth, compressed air was introduced to a pressure of 5 MPa, and the pressure was maintained for 10 minutes to remove excess water. The moisture content of the mud after dewatering was 15%, and the dewatered waste material was obtained.

[0062] V. Repeated kneading and vacuum kneading:

[0063] ① After dewatering, the waste material is kneaded in a twin-shaft kneader for 15 minutes and then put into a vacuum ply mash machine (vacuum degree -0.096MPa) for ply mash making;

[0064] ② Repeat step 5① once to obtain homogenized mud and remove air bubbles to obtain recycled mud;

[0065] VI. Adhesion Evaluation:

[0066] Standard wet blanks were prepared from the recycled clay material, and the flexural strength was measured to be 0.78 MPa. The strength of the original clay material was 0.90 MPa, and the strength ratio was 86.7%, which was deemed qualified, and qualified homogenized recycled ceramic film clay material was obtained.

[0067] VII. Reuse:

[0068] The qualified homogenized recycled ceramic film material was mixed with the virgin material at a mass ratio of 3:7, and then extruded to form a new ceramic film green body with good quality.

[0069] Example 2: A method for recycling green waste from ceramic membrane production, comprising the following steps:

[0070] I. Waste Collection and Classification:

[0071] Collect dried green blanks of the same type of silicon carbide material;

[0072] II. Moisture Content Determination and Crushing:

[0073] The initial moisture content of the waste was determined to be 2.8%. It was crushed into fine particles with a D90 of about 1 mm to obtain the crushed waste.

[0074] III. Vacuum saturation:

[0075] The crushed waste material is put into a vacuum saturation tank, vacuumed to -0.095MPa and maintained for 10 minutes, then deionized water is injected until it is completely submerged. The vacuum state is maintained for 40 minutes to allow water to penetrate into the waste particles, resulting in saturated waste material.

[0076] IV. Pressure Dehydration:

[0077] Using a diaphragm filter press, compressed air at 0.8 MPa is introduced into the diaphragm side to dewater the material; after dewatering, the moisture content of the mud is 12%, resulting in dewatered waste.

[0078] V. Repeated kneading and vacuum kneading:

[0079] ① After dewatering, the waste material is kneaded in a twin-shaft kneader for 20 minutes and then put into a vacuum ply mash machine (vacuum degree -0.098MPa) for ply mash making;

[0080] ② Repeat step 5① 3 times to obtain homogenized mud and remove air bubbles to obtain recycled mud;

[0081] VI. Adhesion Evaluation:

[0082] Standard wet blank test strips were prepared from the recycled clay material, and the wet blank strength of the recycled clay material was measured to be 95% of that of the virgin material; it was deemed qualified, and qualified homogenized recycled ceramic film clay material was obtained.

[0083] VII. Reuse:

[0084] The molding process uses 100% recycled clay, ensuring that the quality of the green body meets the standards.

[0085] The above embodiments demonstrate that the method of the present invention can effectively recycle ceramic membrane drying green waste, and the recycled mud has excellent performance.

[0086] This invention is not limited to the above embodiments. Any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method for recycling green waste from the ceramic membrane production process, characterized in that, The method includes the following steps: I. Waste Collection and Classification: Waste generated during the drying process of ceramic film green bodies is classified and collected according to its basic material to obtain the classified waste. II. Moisture Content Determination and Crushing: The initial moisture content of the sorted waste was determined, and the waste was mechanically crushed. The particle size of the crushed material was controlled to obtain the crushed waste. III. Vacuum saturation: The crushed waste material is degassed and soaked in water under a continuous negative pressure vacuum environment, so that water penetrates into the interior of the waste particles to obtain water-saturated waste material. IV. Pressure Dehydration: External air pressure is applied to the saturated waste to remove excess surface moisture and precisely adjust the moisture content of the waste to a plastic state suitable for plucking, thus obtaining dewatered waste. V. Repeated kneading and vacuum kneading: ① The dehydrated waste material is kneaded and vacuum slurry processed in sequence; ② Repeat step 5① to obtain homogenized mud and remove air bubbles to obtain recycled mud; VI. Adhesion Evaluation: The molding performance of the recycled clay is evaluated, and it can only be reused after it meets the standards, thus obtaining homogenized recycled ceramic membrane clay.

2. The method for recycling green waste in the ceramic membrane production process according to claim 1, characterized in that, The basic materials mentioned in step one include alumina, silicon carbide, silicon dioxide, mullite, and aluminum titanate.

3. The method for recycling green waste in the ceramic membrane production process according to claim 1, characterized in that, The mechanical crushing described in step two uses a jaw crusher, a double roll crusher, or a shear crusher; the particle size D90 of the crushed material described in step two is 0.5~5mm.

4. The method for recycling green waste in the ceramic membrane production process according to claim 1, characterized in that, The absolute pressure of the negative pressure vacuum environment mentioned in step two shall not exceed -0.08 MPa; the degassing and water immersion time mentioned in step two shall be 15 min to 60 min.

5. A method for recycling green waste from ceramic membrane production according to claim 1, characterized in that, The external air pressure mentioned in step four is provided by an air compressor combined with a bottom-venting vacuum sealing device, with a pressure range of 1MPa to 15MPa; the moisture content of the dehydrated waste material mentioned in step four is 8% to 20%.

6. The method for recycling green waste in the ceramic membrane production process according to claim 1, characterized in that, The kneading process described in step 5① is carried out in a twin-shaft kneader for a kneading time of not less than 10 minutes; the vacuum degree of the vacuum slurry treatment described in step 5① is not higher than -0.095MPa.

7. The method for recycling green waste in the ceramic membrane production process according to claim 1, characterized in that, Repeat step 5.1 at least once in step 5.

2.

8. A method for recycling green waste from ceramic membrane production according to claim 1, characterized in that, In step six, the recycled clay is made into standard-sized test strips, and its flexural strength in the wet state is measured. When the strength value is not less than 85% of the wet strength of the original clay in the same period, it is judged to be qualified.

9. A homogenized regenerated ceramic film slurry obtained by the method according to any one of claims 1 to 8.

10. A ceramic film green body, characterized in that, It is obtained by extrusion molding of the homogenized recycled ceramic membrane mud as described in claim 8, or by extrusion molding of homogenized recycled ceramic membrane mud and virgin mud mixed in a certain proportion.