Magnesia reinforced porcelain grouting green body as well as preparation method and application thereof

Abstract

The invention discloses a magnesium reinforced porcelain grouting green body as well as a preparation method and application thereof, and belongs to the technical field of magnesium reinforced porcelain. The preparation method comprises the following steps: adding water into a magnesium reinforced ceramic mineral aggregate, oxalic acid and sodium hexametaphosphate, carrying out ball milling, carrying out filter pressing dehydration, adding a diluent, carrying out slurrying, carrying out slurry mixing, and carrying out molding so as to obtain a magnesium reinforced ceramic grouting green body; wherein the magnesium reinforced porcelain mineral aggregate is 1000 parts by weight, the oxalic acid is 0.2-0.6 part by weight, the sodium hexametaphosphate is 0.3-0.5 part by weight, and the diluent is 0.5-0.8 part by weight. According to the preparation method, oxalic acid and sodium hexametaphosphate are added in the preparation process of the magnesium reinforced porcelain grouting green body, so that the'alkali skin 'phenomenon of the magnesium reinforced porcelain grouting green body is effectively improved, the green body washing efficiency and quality can be effectively improved, and high-quality magnesium reinforced porcelain can be efficiently prepared.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnesia reinforced porcelain, and particularly relates to a magnesia reinforced porcelain slip casting body and a preparation method and application thereof. BACKGROUND

[0002] Magnesia reinforced porcelain is a high-grade ceramic comparable to bone porcelain, but the surface of the magnesia reinforced porcelain slip casting rough body after baking is prone to "alkali skin", which cannot be effectively solved for a long time, seriously affecting the washing quality, especially in the places with reliefs, the spout, the handle and the rim are easy to be washed and deformed, and the reliefs are easy to be washed and have insufficient relief feeling, and the surface of the fine body after the slip casting body is baked is also prone to "alkali skin", which affects the subsequent process and the quality of the magnesia reinforced porcelain; it is of great significance to reduce the "alkali skin" of the magnesia reinforced porcelain slip casting body to improve the quality of the magnesia reinforced porcelain. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the application provides a magnesia reinforced porcelain slip casting body and a preparation method and application thereof, the surface of the magnesia reinforced porcelain slip casting rough body after baking is rarely "alkali skin", which can effectively improve the washing efficiency and quality, the surface of the fine body after the slip casting body is baked is also rarely "alkali skin", the surface of the body is smooth and flat, and high-quality magnesia reinforced porcelain can be efficiently prepared.

[0004] The technical scheme adopted by the application to solve the technical problems is as follows:

[0005] The application provides a preparation method of a magnesia reinforced porcelain slip casting body, which comprises the following steps:

[0006] ball milling, pressure filtration and dewatering, adding a diluent to slurry, slurry adjustment, shaping, and obtaining the magnesia reinforced porcelain slip casting body;

[0007] Preferably, the ball milling slurry is subjected to fineness detection before pressure filtration and dewatering, slurry discharge, sieving and iron removal.

[0008] Further preferably, the slurry is discharged after the fineness detection is less than or equal to 0.1wt% of 325 mesh fineness.

[0009] Further preferably, the slurry is discharged after the fineness detection is less than or equal to 0.1wt% of 325 mesh fineness.

[0010] Preferably, the shaping is performed by sieving the slurry obtained by slurry adjustment, aging, vacuum slip casting, demolding, baking, washing, and drying.

[0011] Preferably, the mass ratio of the magnesia reinforced porcelain mineral material to water is 1:(0.8-1.2).

[0012] Preferably, the pressure filtration and dewatering are performed to a water content of 20-30wt%.

[0013] Preferably, the specific gravity of the slurry after the sizing is 1.70-1.73 g / ml, and the flow rate is 25-35 seconds / 100 ml.

[0014] Preferably, the magnesium-based strengthening porcelain mineral material comprises, by weight parts: raw talc 400-600 parts, calcined talc 400-200 parts, water-milled potash feldspar 40-80 parts, Longyan machine-piled mud 30-80 parts, and Tangxian soil 80-30 parts. The use of Tangxian soil and Longyan machine-piled mud and other soft kaolin clay to replace Inner Mongolia bentonite, plasticizer and other high-strength plastic raw materials further reduces the generation of "alkali skin" and reduces the bending strength of the green body.

[0015] Further preferably, the magnesium-based strengthening porcelain mineral material is composed of, by weight parts: raw talc 400-600 parts, calcined talc 400-200 parts, water-milled potash feldspar 40-80 parts, Longyan machine-piled mud 30-80 parts, and Tangxian soil 80-30 parts.

[0016] Further preferably, the magnesium-based strengthening porcelain mineral material comprises, by weight parts: raw talc 400-600 parts, calcined talc 400-200 parts, water-milled potash feldspar 40-80 parts, Longyan machine-piled mud 30-80 parts, and Tangxian soil 80-30 parts.

[0017] Further preferably, the MgO content in the raw talc is ≥28 wt% and the CaO content is ≤3.5 wt%;

[0018] Further preferably, the MgO content in the calcined talc is ≥30 wt% and the CaO content is ≤3.5 wt%;

[0019] Further preferably, the K2O+Na2O content in the water-milled potash feldspar is ≥12 wt% and the K2O content is ≥10.5 wt%;

[0020] Further preferably, the Fe2O3 content in the Longyan machine-piled mud is ≤0.2 wt% and the TiO2 content is ≤0.03 wt%;

[0021] Further preferably, the Fe2O3 content in the Tangxian soil is ≤0.2 wt% and the TiO2 content is ≤0.03 wt%.

[0022] Preferably, the Fe2O3 content in the magnesium-based strengthening porcelain mineral material is ≤0.15 wt% and the TiO2 content is ≤0.07 wt%;

[0023] Preferably, the diluent is DOLAPIX PC67. The use of this diluent can reduce the amount of diluent, further improve the performance of the slurry and reduce the generation of "alkali skin".

[0024] Preferably, the chemical composition of the magnesia reinforced porcelain mineral material is: 56-63wt% SiO2, 3.5-5wt% Al2O3, 0.05-0.1wt% Fe2O3, 0.05-0.1wt% TiO2, 2.5-3.5wt% CaO, 22-24.5wt% MgO, 0.5-1.5wt% K2O, 0.2-0.6wt% Na2O.

[0025] The application provides a magnesia reinforced porcelain injection-molding blank, which is prepared by the preparation method.

[0026] The application provides a magnesia reinforced porcelain, which is prepared from the magnesia reinforced porcelain injection-molding blank.

[0027] The application provides a preparation method of magnesia reinforced porcelain, which comprises the following steps:

[0028] The magnesia reinforced porcelain is obtained by high-temperature sintering, glazing, glaze firing, color drawing and processing of the magnesia reinforced porcelain injection-molding blank.

[0029] The magnesia reinforced porcelain injection-molding blank of the application takes Jiangxi Shangrao Guangfeng talc as the main raw material, and 0.02-0.06% oxalic acid and 0.03-0.05% sodium hexametaphosphate are added into the blank during ball milling, the total mass of the blank formula is 0.02-0.06% oxalic acid and 0.03-0.05% sodium hexametaphosphate, the oxalic acid can react with calcium in the mud to produce calcium oxalate, which flows away with water during pressure filtration and dehydration, the oxalic acid also has a certain dispersion effect, so that the particles in the mud are more evenly dispersed, the fluidity of the mud is adjusted, the content of calcium ions on the surface of the blank is reduced, the very hard calcium carbonate generated after the blank is dried is prevented, and the generation of "alkali skin" is fundamentally reduced or eliminated; the sodium hexametaphosphate dilutes the mud, can combine with calcium ions and magnesium ions to prevent precipitation, and makes the generated calcium oxalate colloidal particles not to be precipitated and gathered into groups, improves the uniformity, and is beneficial to the smooth flow of the calcium oxalate colloidal particles with water; the sodium hexametaphosphate is easily soluble in water, can be hydrolyzed to generate orthophosphate in water, can soften the surface of the blank, and prevent calcium ions and magnesium ions in the mud from forming water scale; the sodium hexametaphosphate can be adsorbed on the surface of the mud particles, so that the surface has the same electric charge, the particles are dispersed from each other by electrostatic repulsion, the viscosity of the mud is reduced, the mud can better fill the mold, and the uniformity and smoothness of the surface of the blank are ensured; the sodium hexametaphosphate can also form a stable complex with calcium ions in the mud, reduces the flocculation of the plastic clay in the mud by such ions, makes the mud maintain a good deflocculation state during use, prevents the occurrence of coagulation, and through the dispersion and deflocculation, the mud particles are more evenly distributed, the stratification and sedimentation are reduced, and the stability is improved.

[0030] The application uses Tangxian soil and Longyan machine mud and other soft kaolin to replace high-priced and extremely unstable quality Inner Mongolia bentonite, plasticizer and other high-strength plastic raw materials, further reduces the generation of "alkali skin"; at the same time, the dry green body bending strength of the processed mud is reduced from the original 0.6 MPa or more to 0.45-0.5 MPa, and the surface of the green body is appropriately softened, which is more beneficial to washing the green body.

[0031] The application uses the German diluent DOLAPIX PC67 (main component is a mixture of sodium salt and polycarboxylic acid, easily soluble in water and can be completely dispersed, has a wide decondensation range, reduces thixotropy, does not foam, and can also adjust the viscosity of the mud) instead of the diluent with poor dilution effect such as water glass, the amount of the diluent is greatly reduced, the total amount of the diluent is reduced from 0.2% to 0.06-0.08% under the same flow rate, the diluent of the mud is not easy to gather on the surface of the green body, the mud is more uniform in dilution, the decondensation is more thorough, the thixotropy of the mud is lower and more stable, and is between 1.4-1.6, so that the diluent is not easy to gather and is not easy to produce local hard shell during the use of the mud, and the generation of "alkali skin" is further reduced.

[0032] The mineral raw materials such as raw talc and calcined talc used in the application are rich in mineral resources and have a lower price.

[0033] The magnesium-based reinforced porcelain injection-molded green body of the application has less "alkali skin" phenomenon and has a wide use scenario.

[0034] The main crystal phase in the porcelain body of the magnesium-based reinforced porcelain injection-molded product of the application is stable orthoenstatite after high-temperature vitrification, and the performance is excellent.

[0035] The beneficial effects of the application are:

[0036] The application effectively improves the "alkali skin" phenomenon of the magnesium-based reinforced porcelain injection-molded green body by adding oxalic acid and sodium hexametaphosphate during the preparation process of the magnesium-based reinforced porcelain injection-molded green body, can effectively improve the washing efficiency and quality of the green body, and can efficiently prepare high-quality magnesium-based reinforced porcelain. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 respectively, the figures of the dried fine green body products of step 8 of Comparative Example 1 (a), Comparative Example 2 (b), Comparative Example 3 (c), Example 1 (d), Example 2 (e), and Example 3 (f). DETAILED DESCRIPTION

[0038] The application will be further described below in combination with the drawings and examples.

[0039] The concept, specific structure and generated technical effects of the present application will be clearly and completely described below in combination with embodiments and drawings, so as to fully understand the purposes, features and effects of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments, and other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative labor are within the protection scope of the present application. Each technical feature in the present application can be combined with each other as long as they are not contradictory.

[0040] The present application obtains the finished product of magnesia reinforced porcelain by using pure mineral raw materials such as raw talc, calcined talc, water-milled potash feldspar, Longyan machine piled mud and Tangxian soil, etc. through the processes of batching, ball milling mixing, iron removal by sieving, pressure filtration dewatering, mud cake slurry, slurry adjustment, sieving, aging, grouting, demolding, drying, finishing and drying, and then high-temperature baking, glaze spraying, glaze firing, color drawing and processing.

[0041] The specific process flow is as follows:

[0042] Raw and auxiliary material procurement-quality detection-batching-ball milling (with the addition of oxalic acid and sodium hexametaphosphate)-fineness and particle size distribution detection-slurry placing-sieving and iron removal-pressure filtration dewatering-mud cake slurry (with the addition of DOLAPIX PC67 as a diluent)-adjustment of the specific gravity and flow rate of the slurry-sieving-aging for standby-vacuum tank slurry pumping-vacuum defoaming-grouting-residual slurry pouring-demolding-accessory bonding-drying (moisture ≤ 3% for drying completion)-finishing and washing-drying-baking-glaze spraying and glaze firing-decal, and baking-gold drawing and baking-inspection-packaging and delivery.

[0043] Specifically, the following steps are included:

[0044] (1) Selection of mineral raw materials

[0045] High-quality raw talc, calcined talc, water-milled potash feldspar, Longyan machine piled mud, Tangxian soil and other mineral raw materials are selected.

[0046] Preferably, the MgO content of raw talc and calcined talc is controlled to be MgO≥28% and MgO≥30% respectively, and the CaO content is controlled to be CaO≤3.5%; the K2O+Na2O content of water-milled potash feldspar is controlled to be K2O+Na2O≥12%, and the K2O content is controlled to be K2O≥10.5%; the Fe2O3 content of Longyan machine piled mud and Tangxian soil is controlled to be Fe2O3≤0.2%, and the TiO2 content is controlled to be TiO2≤0.03%.

[0047] (2) Batching of mineral raw materials

[0048] The amount of various mineral raw materials required for 1000 Kg of total mineral raw materials is as follows: raw talc (400-600 Kg), calcined talc (400-200 Kg), water-milled potash feldspar (40-80 Kg), Longyan machine-piled mud (30-80 Kg), Tangxian soil (80-30 Kg).

[0049] Preferably, the content of Fe203 and Ti02 in the total mineral raw materials is not more than Fe203≤0.15wt% and Ti02≤0.07wt%.

[0050] Preferably, the chemical composition of the total mineral raw materials is: Si02(56-63%)·Al203(3.5-5%)·Fe203(0.05-0.1%)·Ti02(0.01-0.07%)·CaO(2.5-3.5%)·MgO(22-24.5%)·K20(0.5-1.5%)·Na20(0.2-0.6%).

[0051] (3) Ball milling, sieving, iron removal, pressure filtration dewatering

[0052] The mineral raw materials that have passed acceptance are mixed according to the formula, and a 3-ton ball mill is used for ball milling for 24-28 hours, with the ratio of material: ball: water being 1:(1.8-2.0):(0.8-1.2). The French sea ballstone is used, and the sizes of the ballstone are Φ20-40, Φ40-60, and Φ60-80, with a ratio of 70:20:10. During ball milling, 0.02-0.06% of oxalic acid and 0.03-0.05% of sodium hexametaphosphate are added for ball milling. After passing the particle size and fineness detection, the slurry is sieved through a 250-280 mesh sieve for 4 times, iron is removed, and the mud cake with a water content of about 25% is formed by pressure filtration for use.

[0053] Preferably, the 325 mesh fineness of the mud slurry is ≤0.1%, and the cumulative particle distribution percentage is as shown in the following Table 1.

[0054] Table 1

[0055] 2μm 5μm 10μm 20μm 30μm 44μm 63μm 19-21 45-48 68-71 88-91 96-98 99-99.9 100

[0056] (4) Mud cake slurry, slurry adjustment

[0057] When slurry is formed, 0.5-0.8% of DOLAPIX PC67 diluent is added, the specific gravity of the slurry is controlled to be 1.70-1.73 g / ml, the flow rate is 25-35 seconds / 100 ml of mud slurry, the thixotropy is controlled to be 1.4-1.6, and the PH value of the slurry is controlled to be 8-8.5. The slurry is aged and ready for use.

[0058] (5) Grouting forming, finishing of green body

[0059] The slurry is pumped into a vacuum defoaming tank and vacuumized for more than 4 hours, the vacuum degree is controlled to be more than -0.08 MPa, the slurry is injected into a gypsum mold through a plastic hose, the gypsum mold is used to form the body by absorbing water, the slurry is poured out when the thickness reaches the requirement, then the body is demolded, the accessories are bonded, and the body is baked in a baking room until the water content is less than or equal to 3%, then the body is polished and baked in an oven.

[0060] (6) High-temperature sintering

[0061] The qualified body is sintered at high temperature in a tunnel kiln, the sintering temperature is 1280-1300 DEG C, the sintering period is 17-18 hours, and the sintering is performed in an oxidizing atmosphere. The water absorption of the high-temperature sintered body is less than or equal to 0.25%, and the sintered body can be used in the next process after inspection.

[0062] (7) Glazing and glaze firing

[0063] The qualified sintered body is polished and dried, then is sprayed with glaze in an automatic glazing production line, the glaze used is low-temperature fused glaze, the specific gravity is 1.70-1.72 g / ml, the flow rate is 40-50 seconds, and the thickness of the glaze layer is generally controlled to be 0.1-0.2 mm. The glaze is fired in a tunnel kiln, the glaze firing temperature is 1120-1150 DEG C, and the sintering period is 10-12 hours.

[0064] (8) Color drawing and processing

[0065] The qualified glaze body is pasted, baked, gilded and baked after inspection, and then is matched, packaged and delivered. The baking temperature is generally 860-900 DEG C, and the gilding temperature is generally 830-890 DEG C.

[0066] The following examples and comparative examples of the present application are used to illustrate the effect of the present application by adjusting the amount of oxalic acid, sodium hexametaphosphate and mineral materials.

[0067] The mineral material raw material in the following examples 1-3 and comparative examples 1-4 has a dry basis mass of 1000 kg, and includes: raw talc 460 kg, calcined talc 330 kg, water-milled potash feldspar 50 kg, Longyan mill mud 80 kg, and Tangxian soil 80 kg. The chemical composition is:

[0068] SiO2 (61.62%) · Al2O3 (4.42%) · Fe2O3 (0.08%) · TiO2 (0.07%) · CaO (3.38%) · MgO (22.41%) · K2O (0.8%) · Na2O (0.33%).

[0069] The percentage content of the chemical composition of various raw materials and bodies is shown in Table 2.

[0070] Table 2

[0071] Project Name SiO2 Al2O3 Fe2O3 <![CDATA[TiO2]]> CaO MgO K2O Na2O Raw talc 59.96 0.2 0.08 0.06 2.7 28.59 0.00 0.00 Calcined talc 63.60 0.17 0.09 0.05 3.09 31.26 0.00 0.00 Water-ground potassium feldspar 67.96 17.07 0.09 0.04 0.16 0.07 11.16 2.62 Longyan machine mud pile 53.71 32.13 0.16 0.02 0.26 0.22 2.42 0.49 Tang County soil 73.45 13.4 0.18 0.03 1.25 1.81 0.56 1.78 green body 61.62 4.42 0.08 0.07 3.38 22.41 0.80 0.33

[0072] Example 1:

[0073] Add 0.04wt% oxalic acid and 0.04wt% sodium hexametaphosphate during ball milling.

[0074] Step 1: Accurately weigh the various mineral material raw materials according to the formula ratio, add 0.4kg oxalic acid, 0.4kg sodium hexametaphosphate and 1000kg water, and ball mill together for 25 hours. The slurry moisture content is 50wt%. The fineness reaches 325 mesh residue ≤0.1wt% and can be discharged from the mill.

[0075] Step 2: Discharge the ball-milled material into a pool, pass it through 4 screens with mesh sizes of 250, 270, 270 and 280 meshes respectively, and remove iron using a combination of permanent magnets and electromagnets. The magnetic field strength is ≥8000 Gauss to ensure that the iron removal is as clean as possible.

[0076] Step 3: Filter and dewater. Dewater the slurry to a mud cake with a moisture content of about 25wt%. Calcium oxalate will flow out with the water during this process.

[0077] Step 4: Add water to the mud cake to make it slurry. Add 0.6kg of DOLAPIX pc67 as a diluent. Add the mud cake slowly. Dilute the diluent DOLAPIX pc67 with warm water at 40-50°C at a ratio of water (8) : diluent (1). Add the diluent slowly as the slurry is being made.

[0078] Step 5: Adjust the slurry specific gravity to 1.70-1.73kg / L, the flow rate to 25-35 seconds, the thixotropy to 1.4-1.6, and the pH value to 8-8.5. Add diluent as needed during the slurry adjustment process. After cooling, pass the slurry through a 280 mesh screen twice and let it stand for at least 24 hours.

[0079] Step 6: Use a pipeline to pump the slurry into a vacuum tank and vacuumize it to a vacuum degree of ≥-0.08MPa. The vacuumization time is ≥4 hours.

[0080] Step 7: Prepare the mold for casting. Clean the mold surface of any debris. Use a pipeline to pour the slurry into the gypsum mold. According to the product thickness (weight) requirements, pour out the excess slurry. When the gypsum mold has absorbed water to a moisture content of about 21wt% in the mud, remove the mold. Attach the accessories and send them to the drying oven. The oven temperature should be controlled at 50-60°C. Otherwise, the product may deform or crack. The temperature in this example is 55°C.

[0081] Step 8: When the moisture content of the body is ≤3wt%, trim the body. Clean and smooth the burrs and mold joint lines on the surface of the body. Send it to the drying oven. The oven temperature should be controlled at 80-90°C. The temperature in this example is 85°C.

[0082] Step 9, the dried blank is put into a tunnel kiln for high-temperature sintering, the sintering temperature is 1280-1300℃, and the sintering period is 17-18 hours;

[0083] Step 10, the qualified high-temperature sintered body is sprayed with low-temperature frit glaze, and is glazed in a tunnel kiln, the glazing temperature is 1120-1150℃, and the glazing period is 10-12 hours;

[0084] Step 11, after the qualified glazed body is subjected to decal, baking, gold drawing and gold baking, the magnesia strengthened porcelain product is obtained, the baking temperature is generally 860-900℃, and the gold baking temperature is generally 830-890℃.

[0085] Example 2:

[0086] 0.02wt% oxalic acid and 0.05wt% sodium hexametaphosphate are added during ball milling

[0087] Step 1, various mineral materials are accurately weighed according to the formula proportion, 0.2kg of oxalic acid, 0.5kg of sodium hexametaphosphate and 1000kg of water are added, and ball milling is performed for 25 hours, the slurry moisture is 50wt%, and the fineness reaches 325 mesh residue ≤0.1wt% and can be discharged;

[0088] Step 2, the ball-milled material is put into a pool and passed through 4 screens with mesh sizes of 250, 270, 270 and 280 respectively, and the iron is removed by a combination of permanent magnets and electromagnets; the magnetic field strength is ≥8000 Gauss to ensure that the iron removal is as clean as possible;

[0089] Step 3: pressure filtration and dewatering; the slurry is dewatered to a mud cake with a water content of about 25wt%; during this process, calcium oxalate flows out with water;

[0090] Step 4, the mud cake is added to water for slaking, and 0.6kg of DOLAPIX pc67 is added as a diluent; the diluent DOLAPIX pc67 is first diluted with warm water at 40-50℃, the dilution ratio is water(8): diluent(1), and the diluent is slowly added as the slaking progresses;

[0091] Step 5, the slurry is adjusted to a specific gravity of 1.70-1.73kg / L and a flow rate of 25-35 seconds, the thixotropy is 1.4-1.6, and the pH value is 8-8.5; the diluent is supplemented during the slurry adjustment process according to the slurry state; after cooling, the slurry is passed through a 280 mesh screen twice and is ready for use, and the slurry aging time is not less than 24 hours;

[0092] Step 6, the slurry is pumped into a vacuum tank for vacuumizing, and the vacuum degree is ≥-0.08MPa; the vacuumizing time is ≥4 hours;

[0093] Step 7, prepare the mold for slip casting, clean the surface of the mold of debris, use a pipe to inject the slurry into the gypsum mold, according to the thickness (weight) requirements of the product, pour the excess slurry; the gypsum mold is demolded when the water content of the green body is about 21wt%; bond the accessories and send to the drying oven; the temperature of the drying oven is controlled at 50-60℃, otherwise the product will deform or crack, the temperature in this example is 55℃;

[0094] Step 8, when the water content of the green body is ≤3wt%, trim the green body to clean and smooth the burrs and mold joints on the surface of the green body; send to the drying oven, the temperature of the drying oven is controlled at 80-90℃, otherwise the product will deform or crack, the temperature in this example is 85℃;

[0095] Step 9, the dried fine green body is put into a tunnel kiln for high temperature body burning, the body burning temperature is 1280-1300℃, and the burning period is 17-18 hours;

[0096] Step 10, the qualified high temperature body is sprayed with low temperature fritted glaze and is glaze fired in a tunnel kiln, the glaze firing temperature is 1120-1150℃, and the firing period is 10-12 hours;

[0097] Step 11, after decal, firing, gold drawing and gold firing, the qualified glaze body is obtained as the finished product of magnesia reinforced porcelain; the firing temperature is generally 860-900℃, and the gold firing temperature is generally 830-890℃.

[0098] Example 3:

[0099] 0.06wt% oxalic acid and 0.03wt% sodium hexametaphosphate are added during ball milling

[0100] Step 1, accurately weigh various mineral raw materials according to the formula proportion, add 0.6kg of oxalic acid, 0.3kg of sodium hexametaphosphate and 1000kg of water, and ball mill together for 25 hours, the slurry moisture is 50wt%; the fineness reaches 325 mesh residue ≤0.1wt% and can be discharged;

[0101] Step 2, discharge the ball mill into a pool, pass through 4 screens with mesh sizes of 250, 270, 270 and 280 respectively, and remove iron by combining permanent magnets and electromagnets; the magnetic field strength is ≥8000 Gauss to ensure that the iron removal is as clean as possible;

[0102] Step 3: pressure filtration and dewatering; dewater the slurry to a mud cake with a water content of about 25wt%; during this process, calcium oxalate will flow out with the water;

[0103] Step 4, slurry the mud cake with water, add 0.6kg of DOLAPIX pc67 as a diluent; add the mud cake slowly, dilute the diluent DOLAPIX pc67 with warm water at 40-50℃ first, the dilution ratio is water (8) : diluent (1), and add slowly as the slurry progresses;

[0104] Step 5, the proportioning slurry specific gravity is 1.70-1.73 kg / L, the flow rate is 25-35 seconds, the thixotropy is 1.4-1.6, the pH value is 8-8.5, the proportioning process is supplemented with diluent according to the slurry state; after cooling, the slurry is passed through a second 280 mesh screen for use, and the slurry aging time is not less than 24 hours;

[0105] Step 6, the mud is pumped into a vacuum tank by a pipeline for vacuumizing, and the vacuum degree is ≥-0.08 MPa; the vacuumizing time is ≥4 hours;

[0106] Step 7, a mold for grouting is prepared, the surface of the mold is cleaned of sundries, the mud is injected into the gypsum mold by a pipeline, and the excess mud is poured according to the thickness (weight) requirement of the product; the gypsum mold is demolded when the water content of the mud is about 21wt%; the accessories are bonded and sent to a drying oven; the temperature of the drying oven is controlled at 50-60℃, otherwise the product will be deformed or cracked, and the temperature in this embodiment is 55℃;

[0107] Step 8, when the water content of the body is ≤3wt%, the body is washed and cleaned, and the burrs and mold joint lines on the surface of the body are cleaned and smoothed; the body is sent to a drying oven, and the temperature of the drying oven is controlled at 80-90℃, otherwise the product will be deformed or cracked, and the temperature in this embodiment is 85℃;

[0108] Step 9, the dried body is put into a tunnel kiln for high-temperature body burning, the body burning temperature is 1280-1300℃, and the burning period is 17-18 hours;

[0109] Step 10, the qualified high-temperature body is sprayed with low-temperature fritted glaze, and is glaze-burned in a tunnel kiln, the glaze-burning temperature is 1120-1150℃, and the burning period is 10-12 hours;

[0110] Step 11, after the qualified glaze body is pasted, baked, gilded and baked, a magnesia reinforced porcelain product is obtained; the baking temperature is generally 860-900℃, and the gilding temperature is generally 830-890℃.

[0111] Comparative Example 1

[0112] oxalic acid and sodium hexametaphosphate are not added

[0113] Step 1, accurately weigh various mineral raw materials according to the formula proportion, add 1000 kg of water, and ball mill together for 25 hours, the slurry moisture is 50wt%; the fineness is 325 mesh, and the residue is ≤0.1wt% for putting into the mill;

[0114] Step 2, put the ball-milled material into the pool, pass through 4 screens with mesh sizes of 250, 270, 270 and 280 respectively, and remove iron by combining permanent magnet and electromagnet; the magnetic field strength is ≥8000 Gauss to ensure that the iron removal is as clean as possible;

[0115] Step 3: dewatering by pressure filtration; the slurry is dewatered to a cake with a moisture content of about 25wt%; in this process calcium oxalate is removed with the water;

[0116] Step 4: the cake is added to water to form a slurry, and 0.6kg of DOLAPIX pc67 is added as a diluent; the cake is added slowly, and the diluent DOLAPIX pc67 is first diluted with warm water at 40-50°C, with a dilution ratio of water (8) : diluent (1), and is added slowly as the slurry is formed;

[0117] Step 5: the slurry is adjusted to a specific gravity of 1.70-1.73kg / L, a flow rate of 25-35 seconds, a thixotropy of 1.4-1.6, and a pH of 8.7, and the diluent is added according to the state of the slurry during the adjustment; after cooling, the slurry is passed through a 280-mesh screen and is used after aging for not less than 24 hours;

[0118] Step 6: the slurry is pumped into a vacuum tank using a pipe, and is vacuumed to a vacuum degree of not less than -0.08MPa; the vacuuming time is not less than 4 hours;

[0119] Step 7: a mold for casting is prepared, the surface of the mold is cleaned, the slurry is poured into the gypsum mold using a pipe, and the excess slurry is poured according to the thickness (weight) requirement of the product; the gypsum mold is demolded when the water content of the biscuit is about 21wt%; the accessories are bonded and are sent to a drying oven; the temperature of the drying oven is controlled at 50-60°C, otherwise the product will be deformed or cracked; in this example, the temperature is 55°C;

[0120] Step 8: when the water content of the biscuit is not more than 3wt%, the biscuit is trimmed to remove burrs, mold joints and the like, and is sent to a drying oven; the temperature of the drying oven is controlled at 80-90°C; in this example, the temperature is 85°C;

[0121] Step 9: the dried biscuit is fired at a high temperature in a tunnel kiln, and the firing temperature is 1280-1300°C; the firing period is 17-18 hours;

[0122] Step 10: the qualified high-temperature biscuit is glazed with a low-temperature frit glaze, and is fired in a tunnel kiln; the firing temperature is 1120-1150°C; the firing period is 10-12 hours;

[0123] Step 11: after decal, baking, gilding and baking, the qualified glazed biscuit is obtained as a finished product of magnesia reinforced porcelain; the baking temperature is generally 860-900°C, and the baking temperature is generally 830-890°C.

[0124] Comparative Example 2

[0125] During ball milling, only 0.06wt% of oxalic acid is added, and no sodium hexametaphosphate is added

[0126] Step 1, accurately weigh various mineral materials according to the formula, add 0.6 kg of oxalic acid and 1000 kg of water, and ball mill for 25 hours, the moisture content of the slurry is 50wt%, and the fineness reaches 325 mesh, which can be discharged from the mill;

[0127] Step 2, put the ball-milled material into the pool, pass through 4 screens with mesh sizes of 250, 270, 270, and 280, respectively, and remove iron by combining permanent magnets and electromagnets; the magnetic field strength is ≥8000 Gauss to ensure clean iron removal;

[0128] Step 3: filter and dewater; dewater the slurry to a mud cake with a moisture content of about 25wt%; during this process, calcium oxalate will flow out with the water;

[0129] Step 4, add water to the mud cake to make it slurry, and add 0.6 kg of DOLAPIX pc67 as a diluent; add the mud cake slowly, dilute the diluent DOLAPIX pc67 with warm water at 40-50°C first, the dilution ratio is water (8) : diluent (1), and add it slowly as the slurry is mixed;

[0130] Step 5, adjust the slurry specific gravity to 1.70-1.73 kg / L, the flow rate to 38 seconds, the thixotropy to 1.82, and the pH value to 6.8; during the slurry mixing process, supplement the diluent according to the slurry state; after cooling, pass through a 280 mesh screen twice and wait for use, the slurry aging time is not less than 24 hours;

[0131] Step 6, use a pipeline to pump the slurry into a vacuum tank and vacuumize it, the vacuum degree is ≥-0.08 MPa; the vacuumizing time is ≥4 hours;

[0132] Step 7, prepare the mold for grouting, clean the debris on the surface of the mold, use a pipeline to inject the slurry into the gypsum mold, and according to the thickness (weight) requirement of the product, pour out the excess slurry; when the gypsum mold absorbs water to a moisture content of about 21wt% in the mud, demold; bond the accessories and send them to the drying oven; the temperature of the drying oven is controlled at 50-60°C, otherwise the product will deform or crack, the temperature in this example is 55°C;

[0133] Step 8, when the water content of the body is ≤3wt%, trim the body, clean and smooth the burrs, mold joint lines, etc. on the surface of the body; send it to the drying oven, and the temperature of the drying oven is controlled at 80-90°C, the temperature in this example is 85°C;

[0134] Step 9, put the dried and refined body into a tunnel kiln for high-temperature biscuit firing, the biscuit firing temperature is 1280-1300°C, and the firing period is 17-18 hours;

[0135] Step 10, spray low-temperature frit glaze on the qualified high-temperature biscuit, and glaze fire in a tunnel kiln, the firing temperature is 1120-1150°C, and the firing period is 10-12 hours.

[0136] Step 11, qualified glaze body is obtained after the processes of decal, baking, gold drawing and baking; the baking temperature is generally 860-900℃, and the baking gold temperature is generally 830-890℃.

[0137] Comparative Example 3:

[0138] Only 0.05wt% of sodium hexametaphosphate is added during ball milling, and no oxalic acid is added

[0139] Step 1, accurately weigh various mineral materials according to the formula, add 0.5kg of sodium hexametaphosphate and 1000kg of water, and ball mill for 25 hours, the slurry moisture is 50wt%; the fineness reaches 325 mesh residue ≤0.1wt% and can be discharged;

[0140] Step 2, discharge the ball milling material into the pool, pass through 4 screens with mesh sizes of 250, 270, 270 and 280 respectively, and remove iron by combining permanent magnet and electromagnet; the magnetic field strength is ≥8000 Gauss to ensure clean iron removal as much as possible;

[0141] Step 3: filter pressing and dewatering; dewater the slurry to a mud cake with a water content of about 25wt%; during this process, calcium oxalate will flow out with water;

[0142] Step 4, add water to the mud cake to make it slurry, and add 0.6kg of DOLAPIX pc67 as a diluent; add the mud cake slowly, dilute the diluent DOLAPIX pc67 with 40-50℃ warm water first, the dilution ratio is water(8): diluent(1), and add it slowly according to the slurry making progress;

[0143] Step 5, adjust the slurry specific gravity to 1.70-1.73kg / L, the flow rate to 25-35 seconds, the thixotropy to 1.4-1.6, and the pH value to 8.6; supplement the diluent during the slurry making process according to the slurry state; pass through a 280 mesh screen after cooling and wait for use, and the slurry aging time is not less than 24 hours;

[0144] Step 6, use a pipeline to pump the slurry into a vacuum tank to create a vacuum, and the vacuum degree is ≥-0.08MPa; the vacuum time is ≥4 hours;

[0145] Step 7, prepare the mold for grouting, clean the debris on the surface of the mold, use a pipeline to pour the slurry into the gypsum mold, and pour the excess slurry according to the thickness(weight) requirement of the product; demold when the water absorption of the gypsum mold reaches a mud body water content of about 21wt%; bond the accessories and send them to the drying room; control the temperature of the drying room at 50-60℃, otherwise the product will deform and crack, and the temperature of this example is 55℃;

[0146] Step 8, when the green body moisture is less than or equal to 3wt%, the green body is washed and cleaned, and burrs and mold lines on the surface of the green body are washed and cleaned; the green body is sent into a drying room for drying, and the temperature of the drying room is controlled at 80-90°C, and the temperature of the drying room in this embodiment is 85°C;

[0147] Step 9, the dried fine green body is put into a tunnel kiln for high-temperature body firing, the body firing temperature is 1280-1300°C, and the firing period is 17-18 hours;

[0148] Step 10, the qualified high-temperature body is sprayed with low-temperature frit glaze, and is glaze fired in a tunnel kiln, the glaze firing temperature is 1120-1150°C, and the firing period is 10-12 hours;

[0149] Step 11, after the qualified glaze body is subjected to decal, baking, gold drawing and gold baking, the magnesia strengthened porcelain product is obtained; the baking temperature is generally 860-900°C, and the gold baking temperature is generally 830-890°C.

[0150] Comparative Example 4

[0151] 0.04wt% of oxalic acid is replaced by 0.04wt% of hydrochloric acid, and 0.04wt% of sodium hexametaphosphate is added

[0152] Step 1, various mineral materials are accurately weighed according to the formula proportion, 0.4kg of hydrochloric acid (37wt% hydrochloric acid solution) and 0.4kg of sodium hexametaphosphate are added, and 1000kg of water is added, and the mixture is ball milled for 25 hours, the slurry moisture is 50wt%, and the fineness is 325 mesh, and the residue is less than or equal to 0.1wt% so that the ball milling can be stopped;

[0153] Step 2, the ball milled material is put into a pool, and is passed through 4 screens with mesh numbers of 250, 270, 270 and 280 respectively, and the iron is removed by a combination of permanent magnet and electromagnet; the magnetic field strength is greater than or equal to 8000 gauss, so that the iron removal is as clean as possible;

[0154] Step 3, pressure filtration and dehydration; the slurry is dehydrated to a mud cake with a water content of about 25wt%; in this process, calcium oxalate flows out with water;

[0155] Step 4, the mud cake is added to water for slaking, and 0.6kg of DOLAPIX pc67 is added as a diluent; the diluent DOLAPIX pc67 is diluted with warm water at 40-50°C first, the dilution ratio is water (8) : diluent (1), and the diluent is slowly added with the progress of slaking;

[0156] Step 5, the slurry is adjusted to a specific gravity of 1.70-1.73kg / L, a flow rate of 48 seconds, a thixotropy of 2.08, and a pH value of 6.4, and the diluent is supplemented according to the state of the slurry during the slurry adjusting process; after cooling, the slurry is passed through a 280 mesh screen twice and is ready for use, and the slurry aging time is not less than 24 hours;

[0157] Step 6, the slurry is pumped into the vacuum tank by pipeline and vacuumized, the vacuum degree is ≥-0.08 MPa, and the vacuumizing time is ≥4 hours;

[0158] Step 7, the mold for grouting is prepared, the sundries on the surface of the mold are cleaned, the slurry is pumped into the gypsum mold by pipeline, and the excess slurry is poured according to the thickness (weight) requirement of the product; the gypsum mold is demolded when the water content of the biscuit is about 21wt%; the accessories are bonded and sent to the drying room; the temperature of the drying room is controlled at 50-60℃, otherwise the product will be deformed or cracked, and the temperature in this embodiment is 55℃;

[0159] Step 8, when the water content of the biscuit is ≤3wt%, the biscuit is washed and cleaned, the burrs and mold joint lines on the surface of the biscuit are washed and cleaned, and the biscuit is sent to the drying room, and the temperature of the drying room is controlled at 80-90℃, otherwise the product will be deformed or cracked, and the temperature in this embodiment is 85℃;

[0160] Step 9, the dried biscuit is put into the tunnel kiln for high-temperature biscuit firing, the biscuit firing temperature is 1280-1300℃, and the firing period is 17-18 hours;

[0161] Step 10, the qualified high-temperature biscuit is sprayed with low-temperature frit glaze and is glaze-fired in the tunnel kiln, the glaze firing temperature is 1120-1150℃, and the firing period is 10-12 hours;

[0162] Step 11, after the qualified glaze-fired biscuit is pasted, baked, gilded and baked, the magnesium reinforced porcelain product is obtained; the baking temperature is generally 860-900℃, and the gilding temperature is generally 830-890℃.

[0163] Comparative Example 5

[0164] The prepared batch material is as follows: 1000kg of dry base mineral material (bentonite and plasticizer are used): 460kg of raw talc, 330kg of calcined talc, 50kg of water-milled potassium feldspar, 60kg of Longyan mill mud, 70kg of bentonite, and 30kg of plasticizer.

[0165] The percentage content of the chemical components of the bentonite is shown in Table 3.

[0166] Table 3

[0167] SiO2 Al2O3 Fe2O3 TiO2 CaO MgO K2O Na2O 66.79 15.07 0.2 0.06 3.56 3.18 0.11 0.00

[0168] The percentage content of the chemical components of the plasticizer is shown in Table 4.

[0169] Table 4

[0170] SiO2 Al2O3 Fe2O3 TiO2 CaO MgO K2O Na2O 63.12 14.04 1.1 0.18 4.31 3.99 1.27 2.19

[0171] 0.04wt% of oxalic acid and 0.04wt% of sodium hexametaphosphate are added during ball milling.

[0172] Step 1, accurately weigh various mineral materials according to the formula, add 0.4 kg of oxalic acid, 0.4 kg of sodium hexametaphosphate and 1000 kg of water, and ball mill for 25 hours, the moisture content of the slurry is 50wt%; the fineness reaches 325 mesh, and the residue is ≤0.1wt%;

[0173] Step 2, put the ball-milled material into the pool, pass through 4 screens with mesh sizes of 250, 270, 270 and 280 respectively, and remove iron by combining permanent magnet and electromagnet; the magnetic field strength is ≥8000 Gauss to ensure clean iron removal;

[0174] Step 3: filter and dewater; dewater the slurry to a mud cake with a moisture content of about 25wt%; during this process, calcium oxalate will flow out with water;

[0175] Step 4, add water to the mud cake to make it slurry, add 0.6 kg of DOLAPIX pc67 as a diluent; add the mud cake slowly, dilute the diluent DOLAPIX pc67 with 40-50℃ warm water first, the dilution ratio is water(8): diluent(1), and add it slowly according to the slurry state;

[0176] Step 5, adjust the slurry specific gravity to 1.70-1.73 kg / L, the flow rate to 60 seconds, detect the thixotropy to 1.89, and the pH value to 8-8.5, and supplement the diluent according to the slurry state during the slurry adjustment process; after cooling, pass through a 280 mesh screen twice for use, and the slurry aging time is not less than 24 hours;

[0177] Step 6, use a pipeline to pump the slurry into a vacuum tank to create a vacuum, the vacuum degree is ≥-0.08 MPa; the vacuum time is ≥4 hours;

[0178] Step 7, prepare the mold for grouting, clean the debris on the surface of the mold, use a pipeline to pour the slurry into the gypsum mold, and pour the excess slurry according to the thickness(weight) requirement of the product; remove the mold when the water absorption of the gypsum mold reaches a moisture content of about 21wt% in the mud; bond the accessories and send them to the drying oven; the temperature of the drying oven is controlled at 50-60℃, otherwise the product will deform or crack, the temperature of this example is 55℃;

[0179] Step 8, when the water content of the body is ≤3wt%, clean and smooth the burrs and mold joint lines on the surface of the body; send it to the drying oven, and the temperature of the drying oven is controlled at 80-90℃, the temperature of this example is 85℃;

[0180] Step 9, put the dried and refined body into a tunnel kiln for high-temperature baking, the baking temperature is 1280-1300℃, and the baking period is 17-18 hours;

[0181] Step 10, qualified high-temperature body is sprayed with low-temperature frit glaze, and is fired in a tunnel kiln, with a firing temperature of 1120-1150℃ and a firing period of 10-12 hours;

[0182] Step 11, after the qualified glaze body is subjected to decal, baking, gold drawing and baking, a magnesia reinforced porcelain product is obtained, with a baking temperature of 860-900℃ and a gold baking temperature of 830-890℃.

[0183] The data of Examples 1-3 and Comparative Examples 1-5 are shown in Table 2 below:

[0184] Table 5

[0185]

[0186] Note: The amount of diluent in the table is the total amount of diluent for sizing and sizing; the viscosity in the table is the viscosity of the mud after aging in Step 5; the "alkali skin" of the precision blank is observed after drying the precision blank; and the dry blank strength is the strength of the dry blank obtained in Step 7.

[0187] As can be seen from Table 5, the precision blank "alkali skin" obtained in Comparative Examples 1-3 is obvious, and the precision blank "alkali skin" obtained according to the formulations and preparation processes of Examples 1-3 has the best effect;

[0188] In Comparative Example 4, the oxalic acid is replaced with hydrochloric acid which is more acidic, and the precision blank "alkali skin" obtained is obvious, the sizing is not opened, and the mud is in a flocculation state, and the water after pressure filtration is acidic, which increases the difficulty of sewage treatment in the later stage, so it is not feasible in production;

[0189] In Examples 1-3, the raw materials in the formulation of Comparative Example 5 (Inner Mongolia bentonite and Hebei plasticizer are replaced with Hebei Tangxian clay and Longyan machine mud) are replaced, the dry blank bending strength is lower than before, the washing of the blank is easier, and the efficiency of washing the blank can be improved; the viscosity of the mud during note injection is smaller than that of the formulation of Comparative Example 5, which is beneficial to reducing defects such as mud and bubbles in the injection process, and can improve the qualified rate of the precision blank.

[0190] From Figure 1 It can be seen that the product produced in Comparative Example has a serious hard shell and is not easy to wash, and the product after optimization of the formulation and process of Examples has no hard shell and has a smooth surface and is easy to wash.

[0191] Finally, the formulation, process and physicochemical performance indicators of Examples 1-3 also have a certain effect on the black foot (commonly known as black baking spot) of the magnesia reinforced porcelain injection product in the later baking.

[0192] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the described embodiments, and those skilled in the art can make various equivalent modifications or replacements without deviating from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A method for preparing a magnesia-reinforced porcelain slip-casting body, characterized in that: The following steps are involved: The magnesia-reinforced porcelain ore, oxalic acid and sodium hexametaphosphate are ball-milled with water, filtered and dehydrated, a diluent is added to slurry, slurry is adjusted, and formed to obtain a magnesia-reinforced porcelain slip casting body; The preparation method comprises, by weight, 1000 parts of magnesia-reinforced porcelain ore, 0.2-0.6 parts of oxalic acid, 0.3-0.5 parts of sodium hexametaphosphate, and 0.5-0.8 parts of diluent.

2. The method for preparing a magnesia-reinforced porcelain slip-cast body according to claim 1, wherein: Before filter pressing and dehydration, the ball mill slurry is subjected to fineness testing, slurry discharge, screening, and iron removal; the slurry is discharged after the fineness test shows that the slurry has a 325 mesh fineness of ≤0.1wt%; The molding process includes screening the slurry obtained from the slurry mixing, aging, vacuum grouting, demoulding, baking, repairing and washing the blanks, and drying.

3. The method for preparing a magnesia-reinforced porcelain slip-casting body according to claim 1, wherein: The mass ratio of the magnesia-reinforced porcelain ore to water is 1:(0.8-1.2); The filter pressing dehydration is performed to a water content of 20-30 wt %; The specific gravity of the slurry after slurry adjustment is 1.70-1.73 g / ml, and the flow rate is 25-35 seconds / 100 ml.

4. The method for preparing a magnesia-reinforced porcelain slip-casting body according to claim 1, wherein: The magnesia-reinforced porcelain ore comprises, by weight, 400-600 parts of raw talc, 400-200 parts of calcined talc, 40-80 parts of water-ground potassium feldspar, 30-80 parts of Longyan machine-dumped mud and 80-30 parts of Tangxian soil.

5. The method for preparing a magnesia-reinforced porcelain slip-casting body according to claim 4, characterized in that: The magnesia-reinforced porcelain ore comprises, by weight, 460 parts of raw talc, 330 parts of calcined talc, 50 parts of water-ground potassium feldspar, 80 parts of Longyan pestle mud and 80 parts of Tangxian soil.

6. The method for preparing a magnesia-reinforced porcelain slip-casting body according to claim 4 or 5, characterized in that: The raw talc has a MgO content of ≥28 wt% and a CaO content of ≤3.5 wt%; The calcined talc has a MgO content of ≥30 wt% and a CaO content of ≤3.5 wt%; The K2O+Na2O content in the water-milled potassium feldspar is ≥12wt% and K2O ≥10.5wt%; The Longyan machine pile mud has an Fe2O3 content of ≤0.2wt% and a TiO2 content of ≤0.03wt%; The Fe2O3 content in the Tangxian soil is ≤0.2wt% and the TiO2 content is ≤0.03wt%.

7. The method for preparing a magnesia-reinforced porcelain slip-cast body according to claim 1, characterized in that: The Fe2O3 content in the magnesia-reinforced porcelain ore is ≤0.15wt% and the TiO2 content is ≤0.07wt%; The diluent is DOLAPIX PC67.

8. The method for preparing a magnesia-reinforced porcelain slip-casting body according to claim 1, characterized in that: The chemical composition of the magnesia-reinforced porcelain ore is: 56-63wt% SiO2, 3.5-5wt% Al2O3, 0.05-0.1wt% Fe2O3, 0.01-0.07wt% TiO2, 2.5-3.5wt% CaO, 22-24.5wt% MgO, 0.5-1.5wt% K2O, and 0.2-0.6wt% Na2O.

9. A magnesia-reinforced porcelain slurry casting body, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. A magnesia-reinforced porcelain, characterized in that: It is prepared from the magnesia-reinforced porcelain slurry casting body described in claim 9.

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