Acid-resistant special ceramic and preparation method thereof

Abstract

The invention relates to the technical field of high-performance functional ceramic manufacturing, and discloses an acid-resistant special ceramic and a preparation method thereof.The preparation method comprises the following steps that S1, white mud, aluminum oxide, potassium oxide, calcium oxide, sodium oxide, magnesium oxide, zirconium oxide, boric acid, silicon carbide and an adhesive are weighed according to the proportion; s2, putting the weighed raw materials into a ball mill, and fully mixing; s3, in the mixing process, homogenizing equipment or process is used for improving the mixing uniformity. By accurately controlling the sintering temperature and time, it is ensured that a green body is fully densified in the sintering process, the problems of cracks and deformation are avoided, the quality and performance of a product are guaranteed, the compact structure and uniform microstructure of the ceramic are ensured through the efficient sintering technology, the ceramic is endowed with excellent mechanical strength and acid resistance, and the service life of the ceramic is prolonged. The control of natural cooling can effectively avoid thermal stress caused by rapid cooling, and the overall performance and stability of the ceramic product are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of high-performance functional ceramic manufacturing, in particular to an acid-resistant special ceramic and a preparation method thereof. Background Art

[0002] Acid-resistant special ceramics are materials with excellent stability and corrosion resistance in acidic environments and are widely used in chemical, metallurgical, pharmaceutical and other industries. However, existing acid-resistant special ceramics face defects in the preparation process, and these defects significantly affect the performance and application scope of the ceramics.

[0003] Traditional acid-resistant ceramics are susceptible to corrosion when used in an acidic environment for a long time due to the low precision of the raw material ratio, which reduces their acid resistance. During the mixing and molding process, traditional processes cannot ensure the uniformity of the materials, and defects will exist inside, seriously affecting the mechanical strength and durability of the ceramics. In addition, since the air and moisture in the raw materials are not completely removed, the porosity is high during the firing process, which reduces the density and strength of the ceramics, thereby affecting the overall performance of the acid-resistant ceramics.

[0004] Therefore, those skilled in the art provide an acid-resistant special ceramic and a preparation method thereof to solve the problems raised in the above background technology. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides an acid-resistant special ceramic and a preparation method thereof, which solves the problem that traditional acid-resistant ceramics are susceptible to corrosion when used for a long time in an acidic environment due to the low accuracy of the raw material ratio, resulting in reduced acid resistance; and in the mixing and molding process, the traditional process cannot ensure the uniformity of the materials, and defects will exist inside, which seriously affects the mechanical strength and durability of the ceramics. In addition, since the air and moisture in the raw materials cannot be completely removed, the porosity is high during the firing process, which leads to the reduction of the density and strength of the ceramics, thereby affecting the overall performance of the acid-resistant ceramics.

[0006] To achieve the above objectives, the present invention is implemented through the following technical scheme: an acid-resistant special ceramic, comprising the following percentages of raw materials: 40% to 50% white mud, 20% to 25% aluminum oxide, 5% to 10% potassium oxide, 2% to 5% calcium oxide, 2% to 5% sodium oxide, 2% to 5% magnesium oxide, 5% to 10% zirconium oxide, 1% to 3% boric acid, 1% to 3% silicon carbide, and 0.5% to 1% adhesive.

[0007] Preferably, the binder is a single one or a combination of multiple ones of polyvinyl alcohol, methyl cellulose and carboxymethyl cellulose.

[0008] White clay mainly provides the matrix of ceramic materials, giving the materials good formability and processing properties. As the main component, white clay has good plasticity and sintering properties, and can form a dense ceramic structure during the sintering process; aluminum oxide plays a role in improving the hardness and wear resistance of ceramic materials. Adding aluminum oxide can significantly improve the mechanical strength, hardness and wear resistance of ceramic materials, making them have a longer service life in harsh working environments; potassium oxide, as a flux, can reduce the sintering temperature of ceramic materials and promote the sintering process. Reducing the sintering temperature helps save energy, reduce energy consumption during the sintering process, and improve the density and uniformity of ceramic materials; calcium oxide plays a role in stabilizing the structure and enhancing the refractoriness of ceramic materials. Adding calcium oxide can improve the high temperature resistance of ceramic materials and enhance the stability and thermal shock resistance of materials in high temperature environments; sodium oxide, as a flux, can further reduce the sintering temperature of ceramics. Used in combination with potassium oxide, sodium oxide can optimize the sintering process, improve the density and uniformity of ceramics, and reduce sintering. The addition of zirconium oxide can significantly improve the toughness of ceramic materials, reduce the risk of brittle fracture, and improve the overall mechanical properties and durability of materials. Boric acid, as a vitrifying agent, can reduce the sintering temperature, promote the sintering process, reduce the sintering temperature, reduce energy consumption, and improve the sintering efficiency, while enhancing the chemical stability and corrosion resistance of ceramics. Silicon carbide provides high hardness and wear resistance in ceramics. The high hardness of silicon carbide makes ceramic materials perform well in wear environments, significantly improving the service life and wear resistance of materials. Binders play a bonding and plasticizing role in the molding process, making the raw materials easier to mold and process. Binders such as polyvinyl alcohol, methyl cellulose and carboxymethyl cellulose have good bonding properties and thermal stability, and can provide sufficient mechanical strength and stability during the molding and sintering process to ensure the density and uniformity of the blank.

[0009] A method for preparing acid-resistant special ceramics comprises the following steps: S1, weighing white mud, aluminum oxide, potassium oxide, calcium oxide, sodium oxide, magnesium oxide, zirconium oxide, boric acid, silicon carbide and a binder according to a proportion;

[0010] S2, putting the weighed raw materials into a ball mill and mixing them thoroughly;

[0011] S3. During the mixing process, use homogenization equipment or processes to improve mixing uniformity;

[0012] S4. Use vacuum forming equipment to ensure that air inclusion is minimized during the forming process;

[0013] S5. After forming, low-temperature pre-sintering is performed to remove residual air and moisture;

[0014] S6, placing the formed green body into a drying oven for drying;

[0015] S7, placing the dried green body into a kiln and firing it at a high temperature;

[0016] S8. After firing, natural cooling is performed to avoid thermal stress caused by rapid cooling;

[0017] S9. Perform appearance inspection and performance test on the cooled ceramic products, and perform internal structure analysis using a scanning electron microscope and an X-ray diffractometer;

[0018] S10. Qualified acid-resistant special ceramic products shall be protected and packaged using shock-proof and moisture-proof packaging materials to avoid damage during transportation and storage.

[0019] S1 ensures the precise proportion of raw materials, provides a uniform raw material base, and ensures the stable performance and quality of the ceramics; S2 ensures that the various components are fully and evenly mixed through efficient mixing in a ball mill to avoid inconsistent product performance caused by uneven raw materials; S3 further improves the uniformity of raw material mixing to ensure that the internal components of each particle are consistent, thereby improving the mechanical properties and acid resistance of the ceramics; S4 reduces the air content in the green body to avoid the formation of pores during the firing process and improve the density and mechanical strength of the ceramics; S5 pre-firing can effectively remove residual air and moisture in the green body, reduce the formation of pores during the firing process, and further improve the density of the green body; S6 ensures through drying process The moisture in the green body is completely evaporated to prevent cracking or deformation caused by residual moisture during firing; S7 precisely controls the firing temperature and time to fully densify the green body during the sintering process, avoid cracks and deformation, and ensure the mechanical properties and acid resistance of the final ceramic; S8 controls the cooling rate to avoid thermal stress cracking caused by sudden temperature changes, and ensure the structural integrity and stability of ceramic products; S9 uses detailed testing methods to ensure that the internal structure of the ceramic is uniform, dense, and free of obvious defects, thereby ensuring the high quality and high performance of the product; S10 uses reliable packaging measures to prevent ceramic products from being damaged by external factors during transportation and storage, and maintain the integrity and service life of the product.

[0020] Preferably, in step S2, the rotation speed of the ball mill is in the range of 150 r / min to 250 r / min, and the mixing time of the ball mill is in the range of 1.5 h to 2.5 h.

[0021] Preferably, in the step S3, spray drying technology, high shear mixer, ultrasonic mixing, continuous mixer, twin-screw mixer can improve mixing uniformity;

[0022] The spray drying technology: the mixed slurry is sprayed into tiny droplets by a spray dryer, and quickly dried into uniform fine particles in a high-temperature airflow;

[0023] The high shear mixer: the mixed material is placed in the high shear mixer, and the high-speed rotating blade shears the material into fine particles to achieve uniform mixing;

[0024] Ultrasonic mixing: placing the mixed material in an ultrasonic mixer, and using ultrasonic vibration to make the material particles vibrate and collide quickly to achieve uniform mixing;

[0025] The continuous mixer: uses a continuous mixing device to continuously mix the materials during the conveying process through a screw conveying and mixing device;

[0026] The twin-screw mixer: put the materials into the twin-screw mixer, and use the forced shearing and kneading effects generated by the rotation of the twin screws to fully mix the materials.

[0027] Preferably, in the step S4, the specific steps of vacuum forming are: S41, loading the uniformly mixed raw materials into the hopper of the vacuum forming machine;

[0028] S42, start the vacuum pump to vacuum the molding die and raw materials;

[0029] S43, in a vacuum environment, starting a molding device to die-cast the raw material through a mold;

[0030] S44, slowly release the vacuum to avoid deformation or cracking of the blank due to a sudden drop in pressure;

[0031] S45, taking the formed green body out of the mold.

[0032] Preferably, the operating time interval of the vacuum pump is 5 min to 10 min, the pressure interval of the molding equipment is 50 MPa to 100 MPa, and the die-casting time interval of the molding equipment is 1 min to 5 min.

[0033] Preferably, in step S5, the temperature range of low-temperature pre-firing is 200° C. to 300° C., and the time range of low-temperature pre-firing is 1 h to 3 h.

[0034] Preferably, in step S6, the temperature range of the drying oven is 80° C. to 120° C., and the drying time range is 24 h to 48 h.

[0035] Preferably, in the step S7, the kiln firing temperature range is 1200°C to 1400°C, the kiln firing time range is 4h to 8h, and the kiln firing heating rate is 50°C / h to 100°C / h.

[0036] The present invention provides an acid-resistant special ceramic and a preparation method thereof. The present invention has the following beneficial effects:

[0037] 1. The present invention precisely controls the raw material ratio and optimizes the mixing process, so that the acid-resistant special ceramics show excellent acid resistance and can remain stable for a long time in an acidic environment and be free from corrosion. At the same time, the use of ball mill mixing, homogenization treatment and vacuum forming technology can ensure the uniformity and density of the material, significantly reduce internal defects, and improve mechanical strength and durability. In addition, low-temperature pre-firing and vacuum forming effectively remove air and moisture in the raw materials, further reduce the formation of pores during the firing process, and improve the density and strength of the ceramics.

[0038] 2. The present invention ensures that the green body is fully densified during the sintering process by precisely controlling the firing temperature and time, avoiding cracks and deformation problems, and ensuring the quality and performance of the product. The efficient sintering process ensures the dense structure and uniform microstructure of the ceramic, giving it excellent mechanical strength and acid resistance. The control of natural cooling can effectively avoid thermal stress caused by rapid cooling, further improving the overall performance and stability of ceramic products. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0040] In order to make the technical personnel in the technical field understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in combination with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a partial embodiment of the present invention, not a complete embodiment. Based on the embodiment of the present invention, other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present invention.

[0041] The present invention is described in detail below in conjunction with the accompanying drawings:

[0042] Embodiment 1:

[0043] Please see attached Figure 1 An embodiment of the present invention provides an acid-resistant special ceramic, including the following raw material compositions: 45% white mud, 22% aluminum oxide, 8% potassium oxide, 3% calcium oxide, 3% sodium oxide, 3% magnesium oxide, 7% zirconium oxide, 2% boric acid, 2% silicon carbide, and 0.5% polyvinyl alcohol.

[0044] A method for preparing acid-resistant special ceramics comprises the following steps:

[0045] Weigh each raw material according to the above ratio;

[0046] The weighed raw materials were put into a ball mill, mixed for 2 h, and rotated at 200 r / min;

[0047] Using spray drying technology, the mixed slurry is sprayed into tiny droplets through a spray dryer and quickly dried into uniform fine particles in a high-temperature airflow at 200°C;

[0048] Load the evenly mixed raw materials into the hopper of the vacuum forming machine;

[0049] Start the vacuum pump and run it for 7 minutes to evacuate the molding mold and raw materials;

[0050] In a vacuum environment, the molding equipment is started, the pressure is 80MPa, the die-casting time is 3min, and the die-casting is performed;

[0051] Slowly release the vacuum and take the formed body out of the mold;

[0052] The pre-burning temperature is 250℃ and the pre-burning time is 2h to remove residual air and moisture;

[0053] The formed green body was placed in a drying oven at a drying temperature of 100°C for 36 hours;

[0054] The dried green body was placed in a kiln, fired at 1300°C, for 6 hours, at a heating rate of 75°C / h;

[0055] After firing, it is cooled naturally at a cooling rate of 50℃ / h;

[0056] Use scanning electron microscope and X-ray diffractometer to carry out appearance inspection and performance test on the cooled ceramic products;

[0057] The acid-resistant special ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0058] Summary: Example 1 uses spray drying technology and precisely controlled vacuum forming steps to ensure uniform mixing and dense molding of ceramic raw materials. The optimized firing and cooling processes effectively avoid cracking and deformation problems, so that the final product has excellent acid resistance and mechanical strength.

[0059] Embodiment 2:

[0060] Please refer to the attached Figure 1 An embodiment of the present invention provides an acid-resistant special ceramic, including the following raw material compositions: 42% white mud, 23% aluminum oxide, 7% potassium oxide, 4% calcium oxide, 2% sodium oxide, 4% magnesium oxide, 6% zirconium oxide, 2% boric acid, 3% silicon carbide, and 0.5% methyl cellulose.

[0061] A method for preparing acid-resistant special ceramics comprises the following steps:

[0062] Weigh each raw material according to the above ratio;

[0063] The weighed raw materials were put into a ball mill, mixed for 1.5 h, and rotated at 180 r / min;

[0064] Use a high shear mixer to put the mixed material into the high shear mixer, and the high-speed rotating blades will shear the material into fine particles to achieve uniform mixing;

[0065] Load the evenly mixed raw materials into the hopper of the vacuum forming machine;

[0066] Start the vacuum pump and run it for 5 minutes to evacuate the molding die and raw materials;

[0067] In a vacuum environment, the molding equipment is started, the pressure is 70MPa, the die-casting time is 2min, and the die-casting is performed;

[0068] Slowly release the vacuum and take the formed body out of the mold;

[0069] The pre-burning temperature is 220℃ and the pre-burning time is 1.5h to remove residual air and moisture;

[0070] The formed green body was placed in a drying oven at a drying temperature of 90°C for 30 hours.

[0071] The dried green body was placed in a kiln, fired at 1250°C, for 5 hours, at a heating rate of 60°C / h;

[0072] After firing, it is cooled naturally at a cooling rate of 50℃ / h;

[0073] Use scanning electron microscope and X-ray diffractometer to carry out appearance inspection and performance test on the cooled ceramic products;

[0074] The acid-resistant special ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0075] Summary: Example 2 uses a high shear mixer and an optimized vacuum forming process to ensure uniform mixing of the raw materials and compactness of the molding, and avoids cracks and deformation of the green body during the sintering process by controlling the low-temperature pre-sintering, drying and firing process parameters. The final product has excellent acid resistance and mechanical strength and can be stably used in an acidic environment.

[0076] Embodiment three:

[0077] Please refer to the attached Figure 1 An embodiment of the present invention provides an acid-resistant special ceramic, including the following raw material compositions: 48% white mud, 21% aluminum oxide, 6% potassium oxide, 3% calcium oxide, 2% sodium oxide, 5% magnesium oxide, 7% zirconium oxide, 2% boric acid, 2% silicon carbide, and 0.5% carboxymethyl cellulose.

[0078] A method for preparing acid-resistant special ceramics comprises the following steps:

[0079] Weigh each raw material according to the above ratio;

[0080] The weighed raw materials were put into a ball mill and mixed for 2 h at a speed of 150 r / min;

[0081] Use an ultrasonic mixer to place the mixed material in the ultrasonic mixer, and use ultrasonic vibration to make the material particles vibrate and collide quickly to achieve uniform mixing;

[0082] Load the evenly mixed raw materials into the hopper of the vacuum forming machine;

[0083] Start the vacuum pump and run it for 10 minutes to evacuate the molding die and raw materials;

[0084] In a vacuum environment, the molding equipment is started, the pressure is 50MPa, the die-casting time is 5min, and the die-casting is performed;

[0085] Slowly release the vacuum and take the formed body out of the mold;

[0086] The pre-burning temperature is 300℃ and the pre-burning time is 3h to remove residual air and moisture;

[0087] The formed green body is placed in a drying oven at a drying temperature of 120°C for 48 hours;

[0088] The dried green body was placed in a kiln, fired at 1400°C, for 8 hours, at a heating rate of 100°C / h;

[0089] After firing, it is cooled naturally at a cooling rate of 50℃ / h;

[0090] Use scanning electron microscope and X-ray diffractometer to carry out appearance inspection and performance test on the cooled ceramic products;

[0091] The acid-resistant special ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0092] Summary: Example 3 uses an ultrasonic mixer and a relatively high vacuum treatment time to ensure sufficient mixing of the raw materials and compactness of the molding, and further improves the density and strength of the ceramic through high-temperature pre-firing and precise firing processes. The final product has excellent acid resistance and mechanical strength.

[0093] Embodiment 4:

[0094] Please refer to the attached Figure 1An embodiment of the present invention provides an acid-resistant special ceramic, comprising the following raw material compositions in percentages: 40% white mud, 24% aluminum oxide, 7% potassium oxide, 2% calcium oxide, 5% sodium oxide, 4% magnesium oxide, 6% zirconium oxide, 3% boric acid, 3% silicon carbide, and 0.5% of a combination of polyvinyl alcohol and methyl cellulose.

[0095] A method for preparing acid-resistant special ceramics comprises the following steps:

[0096] Weigh each raw material according to the above ratio;

[0097] The weighed raw materials were put into a ball mill, mixed for 2.5 h, and rotated at 250 r / min;

[0098] Using a continuous mixer, the materials are continuously mixed in a continuous mixing device through a screw conveying and mixing device;

[0099] Load the evenly mixed raw materials into the hopper of the vacuum forming machine;

[0100] Start the vacuum pump and run it for 6 minutes to evacuate the molding die and raw materials;

[0101] In a vacuum environment, the molding equipment is started, the pressure is 100 MPa, the die-casting time is 2 minutes, and the die-casting is performed;

[0102] Slowly release the vacuum and take the formed body out of the mold;

[0103] The pre-burning temperature is 200℃ and the pre-burning time is 1h to remove residual air and moisture;

[0104] The formed green body is placed in a drying oven at a drying temperature of 80°C for 24 hours;

[0105] The dried green body was placed in a kiln, fired at 1200°C, for 4 hours, at a heating rate of 50°C / h;

[0106] After firing, it is cooled naturally at a cooling rate of 50℃ / h;

[0107] Use scanning electron microscope and X-ray diffractometer to carry out appearance inspection and performance test on the cooled ceramic products;

[0108] The acid-resistant special ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0109] Summary: Example 4 uses a continuous mixer and a higher vacuum forming pressure to ensure uniform mixing of the raw materials and compactness of the molding, and reduces the porosity of the green body through low-temperature pre-firing and drying treatment. Precise control during the firing process ensures the quality of the ceramic, and the final product has good acid resistance and mechanical strength.

[0110] Embodiment five:

[0111] Please see attached Figure 1 An embodiment of the present invention provides an acid-resistant special ceramic, comprising the following raw material compositions in percentages: 46% white mud, 20% aluminum oxide, 8% potassium oxide, 3% calcium oxide, 4% sodium oxide, 3% magnesium oxide, 8% zirconium oxide, 1% boric acid, 2% silicon carbide, and 0.5% of a combination of polyvinyl alcohol and carboxymethyl cellulose.

[0112] A method for preparing acid-resistant special ceramics comprises the following steps:

[0113] Weigh each raw material according to the above ratio;

[0114] The weighed raw materials were put into a ball mill, mixed for 1.5 h, and rotated at 200 r / min;

[0115] Use a twin-screw mixer, put the materials into the twin-screw mixer, and use the forced shearing and kneading effect generated by the rotation of the twin screws to fully mix the materials;

[0116] Load the evenly mixed raw materials into the hopper of the vacuum forming machine;

[0117] Start the vacuum pump and run it for 5 minutes to evacuate the molding die and raw materials;

[0118] In a vacuum environment, the molding equipment is started, the pressure is 90MPa, the die-casting time is 1min, and the die-casting is performed;

[0119] Slowly release the vacuum and take the formed body out of the mold;

[0120] The pre-burning temperature is 220℃ and the pre-burning time is 2h to remove residual air and moisture;

[0121] The formed green body was placed in a drying oven at a drying temperature of 110°C for 36 hours;

[0122] The dried green body was placed in a kiln, fired at 1350°C, for 6 hours, at a heating rate of 70°C / h;

[0123] After firing, it is cooled naturally at a cooling rate of 50℃ / h;

[0124] Use scanning electron microscope and X-ray diffractometer to carry out appearance inspection and performance test on the cooled ceramic products;

[0125] The acid-resistant special ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0126] Summary: Example 5 uses a twin-screw mixer and moderate vacuum molding pressure to ensure sufficient mixing of the raw materials and the density of the molding, and reduces the porosity of the green body through low-temperature pre-firing and drying treatment. Precise control during the firing process ensures the high quality of the ceramic, and the final product has good acid resistance and mechanical strength.

[0127] Comparative experimental design:

[0128] Experimental purpose: Through comparative experiments, verify the effects of different preparation processes and parameters on the properties of acid-resistant special ceramics, and reflect the advantages of the preparation method in improving the density, acid resistance and mechanical strength of ceramics;

[0129] Comparative experiment 1: mixed process comparative experiment;

[0130] Experimental parameter settings:

[0131] Ball mill mixing: mixing time 1.5h, speed 200r / min

[0132] High shear mixer: high speed rotating blades, mixing time 1h

[0133] Ultrasonic mixer: Ultrasonic frequency 40kHz, mixing time 1h

[0134] Fixed conditions:

[0135] Raw material composition: white mud 45%, aluminum oxide 22%, potassium oxide 8%, calcium oxide 3%, sodium oxide 3%, magnesium oxide 3%, zirconium oxide 7%, boric acid 2%, silicon carbide 2%, polyvinyl alcohol 0.5%;

[0136] Vacuum forming: pressure 80MPa, forming time 3min, vacuum time 5min;

[0137] Firing: temperature 1300℃, time 6h, heating rate 75℃ / h;

[0138] Low temperature pre-burning: temperature 250℃, time 2h;

[0139] Experimental steps:

[0140] According to the proportion, weigh 45% white mud, 22% aluminum oxide, 8% potassium oxide, 3% calcium oxide, 3% sodium oxide, 3% magnesium oxide, 7% zirconium oxide, 2% boric acid, 2% silicon carbide, and 0.5% polyvinyl alcohol;

[0141] The raw materials were put into a ball mill, mixed for 1.5 h, and rotated at 200 r / min;

[0142] The raw materials were put into a high shear mixer and the blades were rotated at high speed for 1 hour;

[0143] The raw materials were placed in an ultrasonic mixer with an ultrasonic frequency of 40 kHz and a mixing time of 1 h;

[0144] Put the mixed raw materials into the hopper of the vacuum forming machine, start the vacuum pump, and set the vacuum time to 5 minutes;

[0145] Start the molding equipment under vacuum environment, the pressure is 80MPa, and the die casting time is 3min;

[0146] Slowly release the vacuum and remove the blank from the mold;

[0147] Low temperature pre-burning, pre-burning temperature 250℃, time 2h;

[0148] Place the green body in a drying oven at 100°C for 36 hours;

[0149] Kiln firing, firing temperature 1300℃, time 6h, heating rate 75℃ / h;

[0150] The cooling rate of natural cooling is 50℃ / h;

[0151] Inspection and testing using scanning electron microscopes and X-ray diffractometers;

[0152] Ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0153] Experimental data table:

[0154] Parameters / Indicators Ball mill mixing High Shear Mixer Ultrasonic mixer Material uniformity medium good Best Mechanical strength (MPa) 85 95 110 Porosity (%) 8 5 3 Acid resistance (weight loss%) 2 1.5 1

[0155] Summary: Ultrasonic mixer performs best in mixing uniformity, mechanical strength and acid resistance, and its optimized mixing process significantly improves the overall performance of ceramics.

[0156] Comparative experiment 2: vacuum forming process comparison experiment;

[0157] Experimental parameter settings:

[0158] Molding pressure 50MPa: vacuum time 5min, molding time 2min;

[0159] Molding pressure 80MPa: vacuum time 7min, molding time 3min;

[0160] Molding pressure 100MPa: vacuum time 10min, molding time 5min;

[0161] Fixed conditions:

[0162] Raw material composition: white mud 45%, aluminum oxide 22%, potassium oxide 8%, calcium oxide 3%, sodium oxide 3%, magnesium oxide 3%, zirconium oxide 7%, boric acid 2%, silicon carbide 2%, polyvinyl alcohol 0.5%;

[0163] High shear mixer: high-speed rotating blades, mixing time 1h;

[0164] Firing: temperature 1300℃, time 6h, heating rate 75℃ / h;

[0165] Low temperature pre-burning: temperature 250℃, time 2h;

[0166] Experimental steps:

[0167] According to the proportion, weigh 45% white mud, 22% aluminum oxide, 8% potassium oxide, 3% calcium oxide, 3% sodium oxide, 3% magnesium oxide, 7% zirconium oxide, 2% boric acid, 2% silicon carbide, and 0.5% polyvinyl alcohol;

[0168] The raw materials were put into a high shear mixer and the blades were rotated at high speed for 1 hour;

[0169] Molding pressure 50MPa: vacuum time 5min, molding time 2min;

[0170] Molding pressure 80MPa: vacuum time 7min, molding time 3min;

[0171] Molding pressure 100MPa: vacuum time 10min, molding time 5min;

[0172] The pre-firing temperature of low-temperature pre-firing is 250℃ and the time is 2h;

[0173] Place the green body in a drying oven at 100°C for 36 hours;

[0174] The firing temperature of the kiln is 1300°C, the time is 6h, and the heating rate is 75°C / h;

[0175] The cooling rate of natural cooling is 50℃ / h;

[0176] Inspection and testing using scanning electron microscopes and X-ray diffractometers;

[0177] Ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0178] Experimental data table:

[0179] Parameters / Indicators Molding pressure 50MPa Molding pressure 80MPa Molding pressure 100MPa <![CDATA[Material density (g / cm 3 )]]> 2.5 2.7 2.9 Mechanical strength (MPa) 80 95 105 Porosity (%) 7 5 3 Acid resistance (weight loss%) 2.5 1.5 1

[0180] Summary: The vacuum forming process with a molding pressure of 100 MPa performs best in terms of material density, mechanical strength and acid resistance. The optimized molding process significantly improves the overall performance of ceramics.

[0181] Comparative experiment 3: Firing process comparison experiment;

[0182] Experimental parameter settings:

[0183] Firing temperature 1200℃: time 4h, heating rate 50℃ / h;

[0184] Firing temperature 1300℃: time 6h, heating rate 75℃ / h;

[0185] Firing temperature 1400℃: time 8h, heating rate 100℃ / h;

[0186] Fixed conditions:

[0187] Raw material composition: white mud 45%, aluminum oxide 22%, potassium oxide 8%, calcium oxide 3%, sodium oxide 3%, magnesium oxide 3%, zirconium oxide 7%, boric acid 2%, silicon carbide 2%, polyvinyl alcohol 0.5%;

[0188] High shear mixer: high-speed rotating blades, mixing time 1h;

[0189] Vacuum forming: pressure 80MPa, forming time 3min, vacuum time 5min;

[0190] Low temperature pre-burning: temperature 250℃, time 2h;

[0191] Experimental steps:

[0192] According to the proportion, weigh 45% white mud, 22% aluminum oxide, 8% potassium oxide, 3% calcium oxide, 3% sodium oxide, 3% magnesium oxide, 7% zirconium oxide, 2% boric acid, 2% silicon carbide, and 0.5% polyvinyl alcohol;

[0193] The raw materials were put into a high shear mixer and the blades were rotated at high speed for 1 hour;

[0194] Put the mixed raw materials into the hopper of the vacuum forming machine, start the vacuum pump, and set the vacuum time to 7 minutes;

[0195] Start the molding equipment under vacuum environment, the pressure is 80MPa, and the die casting time is 3min;

[0196] Slowly release the vacuum and remove the blank from the mold;

[0197] The pre-firing temperature of low-temperature pre-firing is 250℃ and the time is 2h;

[0198] Place the green body in a drying oven at 100°C for 36 hours;

[0199] Firing temperature 1200℃: time 4h, heating rate 50℃ / h;

[0200] Firing temperature 1300℃: time 6h, heating rate 75℃ / h;

[0201] Firing temperature 1400℃: time 8h, heating rate 100℃ / h;

[0202] The cooling rate of natural cooling is 50℃ / h;

[0203] Inspection and testing using scanning electron microscopes and X-ray diffractometers;

[0204] Ceramic products that pass the inspection are packaged in shock-proof and moisture-proof packaging.

[0205] Experimental data table:

[0206] Parameters / Indicators Firing temperature: 1200℃ Firing temperature: 1300℃ Firing temperature: 1400℃ <![CDATA[Material density (g / cm 3 )]]> 2.6 2.7 2.8 Mechanical strength (MPa) 85 95 100 Porosity (%) 6 5 4 Acid resistance (weight loss%) 2 1.5 1.2

[0207] Summary: The process with a firing temperature of 1400°C performs best in terms of material density, mechanical strength and acid resistance. The optimized firing process significantly improves the overall performance of ceramics.

[0208] Summary: Through the above comparative experiments, the effects of different mixing processes, vacuum forming processes and firing processes on the performance of acid-resistant special ceramics were verified. The optimized preparation method significantly improved the material uniformity, density, mechanical strength and acid resistance of the ceramics, and can be used in various harsh acidic environments.

[0209] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A kind of acid-resistant special ceramic, characterized in that: The raw material composition includes the following percentages: 40% to 50% white mud, 20% to 25% aluminum oxide, 5% to 10% potassium oxide, 2% to 5% calcium oxide, 2% to 5% sodium oxide, 2% to 5% magnesium oxide, 5% to 10% zirconium oxide, 1% to 3% boric acid, 1% to 3% silicon carbide, and 0.5% to 1% adhesive.

2. The acid-resistant special ceramic according to claim 1, characterized in that: The binder is a single agent or a combination of multiple agents selected from polyvinyl alcohol, methyl cellulose and carboxymethyl cellulose.

3. A method for preparing an acid-resistant special ceramic, according to the acid-resistant special ceramic of claim 1-2, characterized in that: The method comprises the following steps: S1, weighing white mud, aluminum oxide, potassium oxide, calcium oxide, sodium oxide, magnesium oxide, zirconium oxide, boric acid, silicon carbide and a binder according to a proportion; S2, putting the weighed raw materials into a ball mill and mixing them thoroughly; S3. During the mixing process, use homogenization equipment or processes to improve mixing uniformity; S4. Use vacuum forming equipment to ensure that air inclusion is minimized during the forming process; S5. After forming, low-temperature pre-sintering is performed to remove residual air and moisture; S6, placing the formed green body into a drying oven for drying; S7, placing the dried green body into a kiln and firing it at a high temperature; S8. After firing, natural cooling is performed to avoid thermal stress caused by rapid cooling; S9. Perform appearance inspection and performance test on the cooled ceramic products, and perform internal structure analysis using a scanning electron microscope and an X-ray diffractometer; S10. Qualified acid-resistant special ceramic products shall be protected and packaged using shock-proof and moisture-proof packaging materials to avoid damage during transportation and storage.

4. The method for preparing an acid-resistant special ceramic according to claim 3, characterized in that: In the step S2, the rotation speed of the ball mill is in the range of 150 r / min to 250 r / min, and the mixing time of the ball mill is in the range of 1.5 h to 2.5 h.

5. The method for preparing an acid-resistant special ceramic according to claim 3, characterized in that: In the step S3, spray drying technology, high shear mixer, ultrasonic mixing, continuous mixer, and twin-screw mixer can all improve mixing uniformity; The spray drying technology: the mixed slurry is sprayed into tiny droplets by a spray dryer, and quickly dried into uniform fine particles in a high-temperature airflow; The high shear mixer: the mixed material is placed in the high shear mixer, and the high-speed rotating blade shears the material into fine particles to achieve uniform mixing; Ultrasonic mixing: placing the mixed material in an ultrasonic mixer, and using ultrasonic vibration to make the material particles vibrate and collide quickly to achieve uniform mixing; The continuous mixer: uses a continuous mixing device to continuously mix the materials during the conveying process through a screw conveying and mixing device; The twin-screw mixer: put the materials into the twin-screw mixer, and use the forced shearing and kneading effects generated by the rotation of the twin screws to fully mix the materials.

6. The method for preparing an acid-resistant special ceramic according to claim 3, characterized in that: In the step S4, the specific steps of vacuum forming are: S41, loading the uniformly mixed raw materials into the hopper of the vacuum forming machine; S42, start the vacuum pump to vacuum the molding die and raw materials; S43, in a vacuum environment, starting a molding device to die-cast the raw material through a mold; S44, slowly release the vacuum to avoid deformation or cracking of the blank due to a sudden drop in pressure; S45, taking the formed green body out of the mold.

7. The method for preparing an acid-resistant special ceramic according to claim 6, characterized in that: The operating time interval of the vacuum pump is 5 minutes to 10 minutes, the pressure interval of the molding equipment is 50 MPa to 100 MPa, and the die-casting time interval of the molding equipment is 1 minute to 5 minutes.

8. The method for preparing an acid-resistant special ceramic according to claim 3, characterized in that: In the step S5, the temperature range of the low-temperature pre-burning is 200° C. to 300° C., and the time range of the low-temperature pre-burning is 1 hour to 3 hours.

9. The method for preparing an acid-resistant special ceramic according to claim 3, characterized in that: In the step S6, the temperature range of the drying oven is 80° C. to 120° C., and the drying time range is 24 h to 48 h.

10. The method for preparing an acid-resistant special ceramic according to claim 3, characterized in that: In the step S7, the kiln firing temperature range is 1200° C. to 1400° C., the kiln firing time range is 4 h to 8 h, and the kiln firing heating rate is 50° C. / h to 100° C. / h.

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