Ceramic raw tea dust glaze and preparation method thereof

Abstract

This invention relates to ceramic raw material tea dust glaze and its preparation method, belonging to the field of inorganic materials technology. The method of this invention uses 27-30 parts potassium feldspar, 23-27 parts quartz, 10-14 parts calcite, 11-13 parts talc, 2 parts zinc oxide, 1 part titanium dioxide, 12 parts white kaolin, and 5.4-6 parts vanadium-titanium magnetite as raw materials. After weighing, ball milling, sieving, aging, glazing, and drying, the materials are fired in an oxidizing atmosphere in a conventional electric kiln according to a specific temperature curve, and then cooled in the kiln to obtain the final product. This invention is the first to use Panzhihua vanadium-titanium magnetite as a colorant to prepare tea dust glaze, breaking through the limitations of traditional reduction firing processes and achieving a single firing in a fully oxidizing atmosphere. The resulting product has a warm and delicate glaze surface, a golden glaze with hints of green, a scratch resistance rating of Grade 1, a thermal shock resistance index of 147-160℃, and a chemical corrosion resistance rating of Grade III. The process is simple, low-cost, and suitable for industrialization.

Description

Technical Field

[0001] This invention relates to ceramic raw material tea dust glaze and its preparation method, belonging to the field of inorganic materials technology. Background Technology

[0002] Tea dust glaze, with its yellow-green hue, is simple yet elegant, deep and dignified, exuding a strong sense of antiquity. Traditional tea dust glaze uses iron as the main crystallizing and coloring agent, belonging to the iron-based crystalline glaze family. It is generally fired at a high temperature of 1200℃~1300℃ in a reducing atmosphere. Tea dust glaze exhibits different colors and particle distributions, forming precious varieties such as "crab shell green," "eel yellow," and "tea dust."

[0003] However, traditional tea dust glaze preparation technology has many limitations: traditional processes usually rely on reduction firing in wood-fired or gas-fired kilns, which requires strict control of kiln equipment and atmosphere, and the firing temperature is high and the cycle is long, resulting in high energy consumption and production costs; secondly, the firing process of tea dust glaze is affected by many factors such as ball milling time, material-to-water ratio, glaze thickness, and kiln atmosphere fluctuations, which are extremely difficult to control stably, resulting in unsatisfactory glaze effects and low yield, which seriously restricts the large-scale promotion and application of tea dust glaze technology.

[0004] Patent application CN113105210A discloses a preparation process for tea-dust glaze porcelain with a crack-free glaze. The glaze formula of this process uses potassium feldspar, Dehua quartz, montmorillonite, magnetite, and other raw materials as the main raw materials. The preparation process requires the body to be bisque-fired at 850-880℃ first, then glazed before entering the glaze firing process. The glaze firing process includes multiple stages such as low temperature, decomposition oxidation, strong reduction, and oxidation heat preservation. Among them, the strong reduction stage needs to be carried out for 5-6 hours in an atmosphere with a CO concentration of 7.6-9.2%, and the firing cycle is relatively long. Although the scheme improves the glaze performance by introducing components such as lanthanum oxide and frit, its process still has the following shortcomings: (1) The glaze formula is complex, using expensive raw materials such as lanthanum oxide, and additional frit needs to be prepared, which increases the cost of raw materials and processes; (2) It must rely on a specific strong reducing atmosphere for firing, which requires extremely high sealing and atmosphere control capabilities of the kiln equipment, which cannot be met by ordinary electric kilns, resulting in high equipment investment and operation thresholds; (3) The two-stage firing process (first bisque firing and then glaze firing) is adopted, which is complicated and further increases energy consumption and time costs.

[0005] In summary, existing tea dust glaze technologies generally suffer from problems such as strong dependence on reducing atmosphere, high equipment requirements, complex processes, high energy consumption, and unstable yield. There is an urgent need to develop a tea dust glaze preparation technology that is simple in process, has low equipment requirements, is suitable for firing in an oxidizing atmosphere, and produces excellent glaze effects. Summary of the Invention

[0006] The first objective of this invention is to provide a method for preparing ceramic raw material tea dust glaze.

[0007] To achieve the first objective of this invention, the method includes the following steps:

[0008] (1) Weigh the following raw materials according to the following weight proportions: 27-30 parts of potassium feldspar, 23-27 parts of quartz, 10-14 parts of calcite, 11-13 parts of talc, 2 parts of zinc oxide, 1 part of titanium dioxide, 12 parts of white kaolin, and 5.4-6 parts of vanadium-titanium magnetite.

[0009] (2) The weighed raw materials are ball-milled to obtain a glaze slurry;

[0010] (3) Pass the ball-milled glaze slurry through a 250-mesh sieve;

[0011] (4) Seal the sieved glaze and place it in a dry and cool place to age for more than 24 hours;

[0012] (5) Remove the upper clear liquid from the aged glaze slurry and adjust the specific gravity of the glaze slurry to 1.65–1.75 g / cm³. 3 After stirring evenly, apply the glaze to the surface of the body and immerse it for 10 to 15 seconds to keep the glaze thickness at 1 to 1.5 mm.

[0013] (6) Dry the glazed body for at least 30 minutes;

[0014] (7) The dried green body is fired in an oxidizing atmosphere according to the following temperature profile:

[0015] First stage: Raise the temperature from room temperature to 390-410℃ over 170 minutes, and then hold the temperature for 20 minutes;

[0016] Second stage: Increase the temperature from 390-410℃ to 590-610℃ over 100 minutes, and then hold the temperature for 20 minutes;

[0017] The third stage: the temperature is increased from 590-610℃ to 1110-1120℃, and the heating time is 210 minutes;

[0018] The fourth stage involves raising the temperature from 1110℃~1120℃ to 1220℃~1230℃ over a period of 40 minutes.

[0019] Fifth stage: Cool down from 1220℃~1230℃ to 1050℃ for 170 minutes, and then keep warm at 1050℃ for 90~120 minutes;

[0020] Finally, stop heating and let the furnace cool to room temperature to obtain the final product.

[0021] Oxidizing atmosphere: The oxygen partial pressure in the high-temperature furnace is relatively high, and the furnace gas environment is oxidizing. There is sufficient free O2 in the furnace gas, which can cause oxidation reactions on the surface of materials and samples. Metals are easily oxidized to form oxides, and non-metals are easily oxidized and burned off.

[0022] Oxygen source: Natural ventilation.

[0023] This invention uses vanadium-titanium magnetite, unique to the Panzhihua-Xichang region, as both a colorant and a crystallizing agent. Panzhihua possesses abundant vanadium-titanium magnetite resources. This vanadium-titanium magnetite is not simply iron ore, but a symbiotic mineral containing vanadium, titanium, and other strategic elements. This natural elemental combination makes it a unique source of raw materials for preparing crystalline glazes. Unlike the Fe2O3 chemical reagent or ordinary magnetite commonly used in existing technologies, this invention introduces iron in the form of Fe3O4, while naturally incorporating trace elements such as vanadium and titanium. Under a specific firing regime, crystals with unique color and texture precipitate, creating a glaze effect distinct from traditional tea-dust glazes.

[0024] In one specific embodiment, the vanadium-titanium magnetite in step (1) contains 63.00%–63.05% Fe3O4, 6.79%–6.84% TiO2, and 0.13%–0.18% V2O5; preferably, the vanadium-titanium magnetite also contains 0.46%–0.49% MnO and 0.033%–0.035% Cr2O3.

[0025] In one specific embodiment, the particle size of the various raw materials mentioned in step (1) is greater than 120 mesh.

[0026] In one specific embodiment, the percentage content ratio of Fe3O4, ZnO and TiO2 in the formula of step (1) is 3.40~3.78:1.98~2.00:1.41~1.69.

[0027] In one specific embodiment, the ball milling control ratio of material:ball:water in step (2) is 1:1.8~2.0:0.8~1.2, and the ball milling time is 10~12 minutes; preferably, the ball milling speed is 83 r / min.

[0028] In one specific implementation, in step (7):

[0029] The heating rate in the first stage is 2.06–2.18 °C / min;

[0030] The heating rate in the second stage is 1.80–2.20 °C / min;

[0031] The heating rate in the third stage is 2.38–2.52 °C / min;

[0032] The heating rate in the fourth stage is 2.50–3.00 °C / min;

[0033] The cooling rate in the fifth stage is 1.00–1.06 °C / min.

[0034] The second objective of this invention is to provide a ceramic raw material tea dust glaze.

[0035] To achieve the second objective of the present invention, the ceramic raw material tea dust glaze is prepared by the above-described method.

[0036] In one specific embodiment, its color difference L value is 28.23 to 41.16, a value is 5.24 to 6.82, b value is 13.42 to 19.14; its gloss is 19.42 to 32.51; and its blue light whiteness is 2.52% to 3.71%.

[0037] In one specific embodiment, its scratch resistance is Grade 1, its thermal shock resistance index is 147-160℃ with a standard deviation of 0-16.3℃, and its chemical corrosion resistance is Grade III.

[0038] The third objective of this invention is ceramic products.

[0039] To achieve the third objective of the present invention, the surface of the ceramic product is coated with the above-mentioned ceramic raw material tea dust glaze.

[0040] Beneficial effects

[0041] 1. This invention breaks through the technical limitation that traditional tea dust glaze must rely on reduction firing process. For the first time, it realizes the preparation of tea dust glaze in the oxidizing atmosphere of ordinary electric kiln. It has low equipment requirements, is easy to operate, has a maximum firing temperature of 1230℃, and a short firing cycle. It belongs to the category of medium temperature glaze. Compared with traditional process, it significantly reduces energy consumption and production cost.

[0042] 2. The glaze formula of this invention is simple, using only eight raw materials, all of which are natural mineral clays. No chemical coloring materials or toxic components such as lead and cadmium are added, making it an environmentally friendly raw material glaze. The raw material cost is low, the preparation process is simpler, and the risk of heavy metal leaching is eliminated at the source.

[0043] 3. This invention is the first to use vanadium-titanium magnetite, unique to the Panxi region, as a colorant and crystallizing agent for tea-dust glaze, filling a technological gap in the preparation of tea-dust glaze using vanadium-titanium magnetite. The naturally occurring symbiotic elements in vanadium-titanium magnetite, such as iron, vanadium, titanium, manganese, and chromium, work synergistically under a specific firing regime, giving the glaze a unique artistic effect of a golden base with hints of green. The glaze is warm and jade-like, simple and elegant, distinct from the darker tones of traditional tea-dust glazes.

[0044] 4. This invention, through the synergistic combination of formula and specific temperature curves, achieves stable and controllable glaze effects with a high yield. The color difference L value of the products obtained in each embodiment is 28.23–41.16, a value is 5.24–6.82, b value is 13.42–19.14, gloss is 19.42–32.51, blue light whiteness is 2.52%–3.71%, scratch resistance is Grade 1, thermal shock resistance index is 147–160℃, chemical corrosion resistance is Grade III, and the glaze performance is excellent with good batch-to-batch consistency.

[0045] 5. This invention adopts a one-time firing process, eliminating the need for a bisque firing process. Compared with the existing two-time firing process, it has fewer steps and higher production efficiency. At the same time, the glaze has no special requirements for the body and can be used for both ordinary ceramics and porcelain bodies, making it widely applicable and easy to promote on a large scale. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0047] Figure 2 These are photographs of the tea dust glazes prepared in Examples 1 to 5 of the present invention, where 1 to 5 represent Examples 1 to 5 respectively.

[0048] Figure 3 The images show actual tea dust glazes prepared for Comparative Examples 1 to 5, where 1 to 5 represent Comparative Examples 1 to 5, respectively.

[0049] Figure 4 This is a photograph of an actual vessel made using the tea dust glaze of this invention.

[0050] Figure 5 The sintering temperature curves are for Examples 1-5 and Comparative Examples 1, 4, and 5 of the present invention.

[0051] Figure 6 This is a sintering temperature curve of Comparative Example 2 of the present invention.

[0052] Figure 7 This is a sintering temperature curve of Comparative Example 3 of the present invention. Detailed Implementation

[0053] To achieve the first objective of this invention, the method includes the following steps:

[0054] (1) Weigh the following raw materials according to the following weight proportions: 27-30 parts of potassium feldspar, 23-27 parts of quartz, 10-14 parts of calcite, 11-13 parts of talc, 2 parts of zinc oxide, 1 part of titanium dioxide, 12 parts of white kaolin, and 5.4-6 parts of vanadium-titanium magnetite.

[0055] (2) The weighed raw materials are ball-milled to obtain a glaze slurry;

[0056] (3) Pass the ball-milled glaze slurry through a 250-mesh sieve;

[0057] (4) Seal the sieved glaze and place it in a dry and cool place to age for more than 24 hours;

[0058] (5) Remove the upper clear liquid from the aged glaze slurry and adjust the specific gravity of the glaze slurry to 1.65–1.75 g / cm³. 3 After stirring evenly, apply the glaze to the surface of the body and immerse it for 10 to 15 seconds to keep the glaze thickness at 1 to 1.5 mm.

[0059] (6) Dry the glazed body for at least 30 minutes;

[0060] (7) The dried green body is fired in an oxidizing atmosphere according to the following temperature profile:

[0061] First stage: Raise the temperature from room temperature to 390-410℃ over 170 minutes, and then hold the temperature for 20 minutes;

[0062] Second stage: Increase the temperature from 390-410℃ to 590-610℃ over 100 minutes, and then hold the temperature for 20 minutes;

[0063] The third stage: the temperature is increased from 590-610℃ to 1110-1120℃, and the heating time is 210 minutes;

[0064] The fourth stage involves raising the temperature from 1110℃~1120℃ to 1220℃~1230℃ over a period of 40 minutes.

[0065] Fifth stage: Cool down from 1220℃~1230℃ to 1050℃ for 170 minutes, and then keep warm at 1050℃ for 90~120 minutes;

[0066] Finally, stop heating and let the furnace cool to room temperature to obtain the final product.

[0067] An oxidizing atmosphere is an atmosphere in which no reducing gas is introduced into the kiln, and the kiln relies solely on oxygen from the air.

[0068] This invention uses vanadium-titanium magnetite, unique to the Panzhihua-Xichang region, as both a colorant and a crystallizing agent. Panzhihua possesses abundant vanadium-titanium magnetite resources. This vanadium-titanium magnetite is not simply iron ore, but a symbiotic mineral containing vanadium, titanium, and other strategic elements. This natural elemental combination makes it a unique source of raw materials for preparing crystalline glazes. Unlike the Fe2O3 chemical reagent or ordinary magnetite commonly used in existing technologies, this invention introduces iron in the form of Fe3O4, while naturally incorporating trace elements such as vanadium and titanium. Under a specific firing regime, crystals with unique color and texture precipitate, creating a glaze effect distinct from traditional tea-dust glazes.

[0069] In one specific embodiment, the vanadium-titanium magnetite in step (1) contains 63.00%–63.05% Fe3O4, 6.79%–6.84% TiO2, and 0.13%–0.18% V2O5; preferably, the vanadium-titanium magnetite also contains 0.46%–0.49% MnO and 0.033%–0.035% Cr2O3.

[0070] In one specific embodiment, the particle size of the various raw materials mentioned in step (1) is greater than 120 mesh.

[0071] In one specific embodiment, the percentage content ratio of Fe3O4, ZnO and TiO2 in the formula of step (1) is 3.40~3.78:1.98~2.00:1.41~1.69.

[0072] In one specific embodiment, the ball milling control ratio of material:ball:water in step (2) is 1:1.8~2.0:0.8~1.2, and the ball milling time is 10~12 minutes; preferably, the ball milling speed is 83 r / min.

[0073] In one specific implementation, in step (7):

[0074] The heating rate in the first stage is 2.06–2.18 °C / min;

[0075] The heating rate in the second stage is 1.80–2.20 °C / min;

[0076] The heating rate in the third stage is 2.38–2.52 °C / min;

[0077] The heating rate in the fourth stage is 2.50–3.00 °C / min;

[0078] The cooling rate in the fifth stage is 1.00–1.06 °C / min.

[0079] To achieve the second objective of the present invention, the ceramic raw material tea dust glaze is prepared by the above-described method.

[0080] In one specific embodiment, its color difference L value is 28.23 to 41.16, a value is 5.24 to 6.82, b value is 13.42 to 19.14; its gloss is 19.42 to 32.51; and its blue light whiteness is 2.52% to 3.71%.

[0081] In one specific embodiment, its scratch resistance is Grade 1, its thermal shock resistance index is 147-160℃ with a standard deviation of 0-16.3℃, and its chemical corrosion resistance is Grade III.

[0082] The thermal shock resistance index and sample standard deviation are determined according to the formula in GB / T 3298-2022, "Determination of Thermal Shock Resistance of Daily-Use Ceramic Ware". calculate.

[0083] To achieve the third objective of the present invention, the surface of the ceramic product is coated with the above-mentioned ceramic raw material tea dust glaze.

[0084] The specific embodiments of the present invention will be further described below with reference to examples, but the present invention is not limited to the scope of the embodiments described herein.

[0085] The chemical composition of the raw materials used in the embodiments of the present invention, namely potassium feldspar, quartz, calcite, talc, white kaolin, zinc oxide, titanium dioxide, and vanadium-titanium magnetite, is shown in Table 1.

[0086] Table 1. Chemical composition of raw materials (wt%)

[0087]

[0088] The vanadium-titanium magnetite is mined from the Panxi region of Sichuan Province, with Fe3O4 content of 63.00%–63.05%, TiO2 content of 6.79%–6.84%, V2O5 content of 0.13%–0.18%, MnO content of 0.46%–0.49%, and Cr2O3 content of 0.033%–0.035%.

[0089] All raw materials should be crushed to a particle size greater than 120 mesh before use.

[0090] In this invention, the color difference test uses the SC-80 colorimeter produced by Dongguan Jiapin Company, the gloss test uses the WGG60 gloss meter produced by Shanghai Jieying Electronic Technology Co., Ltd., and the whiteness test uses the SBDY-I whiteness meter produced by Shanghai Yuefeng Instrument Co., Ltd. The measured whiteness is blue light whiteness.

[0091] Example 1

[0092] (1) Weighing: By weight, use an electronic balance to weigh 27 parts potassium feldspar, 25 parts quartz, 14 parts calcite, 11 parts talc, 12 parts white kaolin, 2 parts zinc oxide, 1 part titanium dioxide, and 5.4 parts vanadium-titanium magnetite. The percentage content of Fe3O4, ZnO, and TiO2 is 3.40:1.98:1.64.

[0093] (2) Ball milling: The weighed raw materials are put into a high-speed ball mill, and the ratio of material:ball:water is controlled as 1:2:0.8. After high-speed ball milling for 12 minutes, the raw materials are taken out to obtain glaze slurry.

[0094] (3) Sieving: The ball-milled glaze slurry is sieved through a 250-mesh sieve to remove coarse particles and impurities. A YJKS type high-speed ball mill is used, with a fixed revolution speed of 83 r / min (not adjustable).

[0095] (4) Aging: Seal the sieved glaze and place it in a dry and cool place to age for more than 24 hours.

[0096] (5) Glazing: Remove the upper clear liquid from the aged glaze slurry, maintaining the specific gravity of the glaze slurry at 1.65–1.75 g / cm³. 3 Stir well; wipe the surface of the blank with a damp sponge to remove dust and add water. After the surface of the blank is fully soaked in water, immerse it in glaze for 10 seconds. Repeat the glaze immersion twice to keep the glaze layer thickness at about 1mm.

[0097] (6) Drying: Dry the glazed body for more than 30 minutes to remove excess moisture.

[0098] (7) Firing: The dried ceramic blank is placed in an electric kiln and fired in an oxidizing atmosphere. The specific heating process is divided into the following five stages:

[0099] First stage: heating from room temperature to 400℃ for 170 min, holding for 20 min, with a heating rate of 2.06~2.18℃ / min;

[0100] Second stage: Heat from 400℃ to 600℃ for 100 minutes, hold for 20 minutes, with a heating rate of 2.00℃ / min;

[0101] The third stage: heating from 600℃ to 1120℃ in 210 minutes at a rate of 2.48℃ / min.

[0102] Fourth stage: Increase the temperature from 1120℃ to 1220℃ over 40 minutes at a rate of 2.50℃ / min.

[0103] Fifth stage: Cooling from 1220℃ to 1050℃ for 170 min, holding for 120 min, cooling rate is 1.00℃ / min;

[0104] After the heat preservation period ends, heating is stopped, and the product is cooled to room temperature in the furnace to obtain tea dust glaze.

[0105] The tea dust glaze prepared in this embodiment has a color difference L value of 29.18, an a value of 5.38, and a b value of 13.75; a gloss of 27.61; a blue light whiteness of 2.52%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 153℃ with a standard deviation of 11.6℃; and a chemical corrosion resistance rating of Grade III. The glaze has a golden base color interspersed with specks of green, delicate crystal patterns, a warm and jade-like texture, and a unique and multi-layered color.

[0106] Example 2

[0107] (1) Weighing: By weight, weigh 27 parts potassium feldspar, 25 parts quartz, 10 parts calcite, 11 parts talc, 2 parts zinc oxide, 1 part titanium dioxide, 12 parts white kaolin, and 5.4 parts vanadium-titanium magnetite using an electronic balance. The percentage content of Fe3O4, ZnO, and TiO2 is 3.40:1.98:1.64.

[0108] Steps (2) to (7) are the same as in Example 1.

[0109] The tea dust glaze prepared in this embodiment has a color difference L value of 41.16, an a value of 5.52, and a b value of 13.42; a gloss of 19.42; a blue light whiteness of 3.17%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 160℃; and a chemical corrosion resistance rating of Grade III. The glaze has a dark and warm color, with fine and uniform crystal patterns, and a matte finish that exudes a warm, jade-like texture.

[0110] Example 3

[0111] (1) Weighing: Weigh 30 parts potassium feldspar, 23 parts quartz, 14 parts calcite, 11 parts talc, 2 parts zinc oxide, 1 part titanium dioxide, 12 parts white kaolin, and 5.4 parts vanadium-titanium magnetite by weight using an electronic balance. The percentage content of Fe3O4, ZnO, and TiO2 is 3.40:1.98:1.65.

[0112] Steps (2) to (7) are the same as in Example 1.

[0113] The tea dust glaze prepared in this embodiment has a color difference L value of 28.23, an a value of 5.24, and a b value of 19.14; a gloss of 21.13; a blue light whiteness of 2.68%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 160℃ with a standard deviation of 16.3℃; and a chemical corrosion resistance rating of Grade III. The glaze surface is uniformly distributed with fine, light brown to yellowish-green crystalline dots, with a slightly darker glaze color at the edges, presenting an overall textured effect of "uniform tea dust".

[0114] Example 4

[0115] (1) Weighing: By weight, weigh 27 parts potassium feldspar, 25 parts quartz, 14 parts calcite, 13 parts talc, 2 parts zinc oxide, 1 part titanium dioxide, 12 parts white kaolin, and 6 parts vanadium-titanium magnetite using an electronic balance. The percentage content of Fe3O4, ZnO, and TiO2 is 3.78:1.98:1.69.

[0116] Steps (2) to (7) are the same as in Example 1.

[0117] The tea dust glaze prepared in this embodiment has a color difference L value of 39.25, an a value of 5.87, and a b value of 18.92; a gloss of 32.51; a blue light whiteness of 3.71%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 153℃ with a standard deviation of 11.6℃; and a chemical corrosion resistance rating of Grade III. The glaze has a yellowish tint, a warm and jade-like texture, and an overall good quality.

[0118] Example 5

[0119] (1) Weighing: Weigh out 30 parts by weight of potassium feldspar, 23 parts by weight of quartz, 14 parts by weight of calcite, 11 parts by weight of talc, 2 parts by weight of zinc oxide, 1 part by weight of titanium dioxide, 12 parts by weight of white kaolin, and 6 parts by weight of vanadium-titanium magnetite. The percentage content of Fe3O4, ZnO and TiO2 is 3.78:1.98:1.69.

[0120] Steps (2) to (7) are the same as in Example 1.

[0121] The tea dust glaze prepared in this embodiment has a color difference L value of 37.15, an a value of 6.82, and a b value of 17.62; a gloss of 31.56; a blue light whiteness of 3.11%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 147℃ with a standard deviation of 11.6℃; and a chemical corrosion resistance rating of Grade III. The glaze is relatively light in color, with fine and uniform yellow-green crystals, possessing a warm jade-like frosted texture while also exhibiting a certain degree of glassy quality.

[0122] As can be seen from Examples 1 to 5 above, the tea dust glaze prepared using the formula and preparation method of the present invention has a stable glaze effect and excellent performance. The color difference L value is between 28.23 and 41.16, the a value is between 5.24 and 6.82, the b value is between 13.42 and 19.14, the gloss is between 19.42 and 32.51, the blue light whiteness is between 2.52% and 3.71%, the scratch resistance is the highest level 1, the thermal shock resistance index is 147 to 160℃, and the chemical corrosion resistance is level III. All indicators are consistent.

[0123] Comparative Example 1

[0124] This comparative example uses a different glaze formulation than that of the present invention to examine its firing effect under the temperature curve of the present invention.

[0125] (1) Weighing: By weight, weigh 45 parts potassium feldspar, 25 parts quartz, 15 parts calcite, 7.5 parts talc, 5.4 parts vanadium-titanium magnetite, 0.5 parts white kaolin, 2 parts bentonite, and 10 parts borax using an electronic balance. The percentage content of Fe3O4, ZnO, and TiO2 is 3.40:0:0.42.

[0126] Steps (2) to (7) are the same as in Example 1.

[0127] The tea dust glaze prepared in this comparative example has a color difference L value of 38.53, an a value of 7.52, and a b value of 15.71; a gloss of 18.42; a blue light whiteness of 2.12%; a scratch resistance rating of 2; a thermal shock resistance index of 140℃; and a chemical corrosion resistance rating of III. The glaze surface has relatively coarse crystal particles and a bluish base color. Although it initially resembles a tea dust glaze, its fineness is far inferior to that of the embodiments of this invention, and both its scratch resistance and thermal shock resistance are reduced.

[0128] Comparative Example 2

[0129] This comparative example uses the exact same formulation as Example 1, but the maximum firing temperature and the final temperature profile are changed.

[0130] Steps (1) to (6) are the same as in Example 1.

[0131] (7) Firing: Place the dried ceramic blank into an electric kiln and fire it under an oxidizing atmosphere according to the following temperature curve:

[0132] First stage: heating from room temperature to 400℃ for 170 min, holding for 20 min, with a heating rate of 2.06~2.18℃ / min;

[0133] Second stage: Heat from 400℃ to 600℃ for 100 minutes, hold for 20 minutes, with a heating rate of 2.00℃ / min;

[0134] The third stage: heating from 600℃ to 1120℃ in 210 minutes at a rate of 2.48℃ / min.

[0135] Fourth stage: The temperature is increased from 1120℃ to 1250℃ over a period of 40 minutes at a rate of 3.25℃ / min.

[0136] Fifth stage: Cooling from 1250℃ to 1050℃ for 170 min, holding for 120 min, cooling rate is 1.18℃ / min;

[0137] After the heat preservation period ends, stop heating and allow the furnace to cool to room temperature.

[0138] The tea dust glaze prepared in this comparative example has a color difference L value of 11.98, an a value of 2.78, and a b value of 4.29; a gloss of 38.78; a blue light whiteness of 0.12%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 160℃; and a chemical corrosion resistance rating of Grade III. Although the color meets certain requirements, the glaze surface is not fine enough, exhibiting a noticeable grainy texture, and the overall glaze quality is poor.

[0139] Comparative Example 3

[0140] This comparative example uses the exact same formulation as Example 1, but with a lower maximum firing temperature and a different final temperature profile.

[0141] Steps (1) to (6) are the same as in Example 1.

[0142] (7) Firing: Place the dried ceramic blank into an electric kiln and fire it under an oxidizing atmosphere according to the following temperature curve:

[0143] First stage: heating from room temperature to 400℃ for 170 min, holding for 20 min, with a heating rate of 2.06~2.18℃ / min;

[0144] Second stage: Heat from 400℃ to 600℃ for 100 minutes, hold for 20 minutes, with a heating rate of 2.00℃ / min;

[0145] The third stage: heating from 600℃ to 1120℃ in 210 minutes at a rate of 2.48℃ / min.

[0146] Fourth stage: Heating from 1120℃ to 1200℃ over 40 minutes at a rate of 2.00℃ / min;

[0147] Fifth stage: Cooling from 1200℃ to 1050℃ for 170 minutes, holding at that temperature for 120 minutes, with a cooling rate of 0.88℃ / min;

[0148] After the heat preservation period ends, stop heating and allow the furnace to cool to room temperature.

[0149] The tea dust glaze prepared in this comparative example has a color difference L value of 25.42, an a value of 4.31, and a b value of 15.24; a gloss of 19.46; a blue light whiteness of 2.16%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 140℃; and a chemical corrosion resistance rating of Grade III. Although fine crystal patterns appear, the overall color is rather dark, and the glaze surface exhibits a hazy, "foggy" appearance. The color does not meet the ideal requirements, and the thermal shock resistance is significantly reduced.

[0150] The results of Comparative Examples 2 and 3 show that even when using the same glaze formulation as in this invention, the glaze quality, color, and physical properties deteriorate significantly when the firing temperature profile deviates from the range defined in this invention. This indicates that the formulation of this invention has a close synergistic relationship with the specific firing regime, and both the formulation and the temperature profile are indispensable.

[0151] Comparative Example 4

[0152] This comparative study examines the glaze effect when magnetite from other origins is used instead of vanadium-titanium magnetite.

[0153] (1) Weighing: By weight, weigh 27 parts potassium feldspar, 25 parts quartz, 14 parts calcite, 11 parts talc, 2 parts zinc oxide, 1 part titanium dioxide, 12 parts white kaolin from the Panxi region, and 5.4 parts Yunnan magnetite using an electronic balance. The chemical composition of Yunnan magnetite is shown in Table 1 (omitted below).

[0154] (Note: The colorant used in Comparative Example 4 was "Yunnan magnetite," with an Fe3O4 content of 39.10% and a TiO2 content of 29.12%, which differs significantly from the content range required by this invention. Furthermore, the content of trace elements such as V2O5 was extremely low or absent. The percentage ratio of Fe3O4, ZnO, and TiO2 was approximately 2.11:1.98:2.31.)

[0155] Steps (2) to (6) are the same as in Example 1.

[0156] (7) Firing: Place the dried ceramic blank into an electric kiln and fire it under an oxidizing atmosphere according to the following temperature curve:

[0157] First stage: heating from room temperature to 400℃ for 170 minutes, followed by a 20-minute hold period, with a heating rate of 2.06–2.18℃ / min;

[0158] Second stage: Temperature rises from 400℃ to 600℃ for 100 minutes, followed by a 20-minute hold period, with a heating rate of 2.00℃ / min;

[0159] The third stage: heating from 600℃ to 1120℃ over 210 minutes at a rate of 2.48℃ / min;

[0160] Fourth stage: Heating from 1120℃ to 1220℃ over 40 minutes at a rate of 2.5℃ / min;

[0161] Fifth stage: Cooling from 1220℃ to 1050℃ for 170 minutes, holding at that temperature for 120 minutes, with a cooling rate of 1℃ / min;

[0162] The firing process is carried out in an oxidizing atmosphere.

[0163] The tea dust glaze prepared in this comparative example has the following characteristics: color difference L value is 36.13, a value is 4.52, b value is 7.21; gloss is 11.42; blue light whiteness is 2.23%; scratch resistance is grade 1; thermal shock resistance index is 153℃ with a standard deviation of 11.6℃; and chemical corrosion resistance is grade III. The glaze surface exhibits numerous pores, and the color indicators deviate significantly, failing to meet the required color and texture of tea dust glaze.

[0164] Comparative Example 5

[0165] This comparative example further examines the glaze effect when the amount of Yunnan magnetite is increased.

[0166] (1) Weighing: Weigh 30 parts potassium feldspar, 23 parts quartz, 14 parts calcite, 11 parts talc, 2 parts zinc oxide, 12 parts white kaolin, and 9 parts Yunnan magnetite by weight using an electronic balance, without adding titanium dioxide. The percentage content of Fe3O4, ZnO, and TiO2 is approximately 3.52:1.98:2.01.

[0167] (2) Put the weighed raw material from step (1) into a high-speed ball mill, control the ratio of material:ball:water = 1:2:0.8, and ball mill for 12 minutes. Then take it out and ball mill it again to obtain glaze slurry.

[0168] (3) Pass the ball-milled glaze slurry from step (2) through a 250-mesh sieve to remove coarse particle impurities from the glaze slurry;

[0169] (4) Seal the glaze slurry after sieving in step (3) and place it in a dry and cool place to age for more than 24 hours;

[0170] (5) Remove the upper clear liquid from the glaze slurry after aging in step (4), and maintain the specific gravity of the glaze slurry at 1.65–1.75 g / cm³. 3 Between stirring, use a damp sponge to wipe away the dust on the surface of the blank, which also serves to replenish water. After the surface of the blank is fully soaked in water, apply the glaze. Each glazing time is 10 seconds, and the glaze is applied twice to keep the glaze layer thickness at about 1 mm.

[0171] (6) Dry the glazed body for 30 minutes to remove excess moisture and prevent glaze defects during firing.

[0172] (7) Firing: Place the dried ceramic blank into an electric kiln and fire it under an oxidizing atmosphere according to the following temperature curve:

[0173] First stage: heating from room temperature to 400℃ for 170 minutes, holding for 20 minutes, with a heating rate of 2.06~2.18℃ / min;

[0174] Second stage: heating from 400℃ to 600℃ for 100 minutes, holding for 20 minutes, with a heating rate of 2.00℃ / min;

[0175] The third stage: heating from 600℃ to 1120℃ in 210 minutes at a rate of 2.48℃ / min.

[0176] Fourth stage: heating from 1120℃ to 1220℃ over 40 minutes at a rate of 2.5℃ / min;

[0177] Fifth stage: Cooling from 1220℃ to 1050℃ for 170 minutes, holding for 120 minutes, with a cooling rate of 1℃ / min;

[0178] The firing process is carried out in an oxidizing atmosphere.

[0179] The tea dust glaze prepared in this comparative example has a color difference L value of 37.12, an a value of 4.34, and a b value of 12.26; a gloss value of 12.41; a blue light whiteness of 0.92%; a scratch resistance rating of Grade 1; a thermal shock resistance index of 160℃ with a standard deviation of 16.3℃; and a chemical corrosion resistance rating of Grade III. The glaze surface has visible pores, a darker, almost blackish color, and a noticeable grainy texture, failing to achieve the artistic effect expected of tea dust glaze.

[0180] As shown in the results of Comparative Examples 4 and 5, and in conjunction with Comparative Example 1, under the firing regime of this invention, neither using Yunnan magnetite nor adjusting the formula composition can achieve the desired tea dust glaze effect. This fully demonstrates that the vanadium-titanium magnetite and its specific proportions defined in this invention play an irreplaceable role in obtaining high-quality tea dust glaze.

[0181] Based on the comparative analysis of the above embodiments and comparative examples, it can be concluded that: (1) The present invention uses vanadium-titanium magnetite as a colorant and a glaze formula with a specific ratio. When fired under a specific temperature curve of oxidizing atmosphere defined by the present invention, tea dust glaze products with a warm and delicate glaze surface, elegant color and excellent performance can be stably obtained; (2) The formula and temperature curve are mutually synergistic and inseparable. Deviation from either aspect will lead to a significant decrease in the quality of the glaze surface.

Claims

1. A method for preparing ceramic raw material tea dust glaze, characterized in that, Includes the following steps: (1) Weigh the following raw materials according to the following weight proportions: 27-30 parts of potassium feldspar, 23-27 parts of quartz, 10-14 parts of calcite, 11-13 parts of talc, 2 parts of zinc oxide, 1 part of titanium dioxide, 12 parts of white kaolin, and 5.4-6 parts of vanadium-titanium magnetite. (2) The weighed raw materials are ball-milled to obtain a glaze slurry; (3) Pass the ball-milled glaze slurry through a 250-mesh sieve; (4) Seal the sieved glaze and place it in a dry and cool place to age for more than 24 hours; (5) Remove the upper clear liquid from the aged glaze slurry and adjust the specific gravity of the glaze slurry to 1.65–1.75 g / cm³. 3 After stirring evenly, apply the glaze to the surface of the body and immerse it for 10 to 15 seconds to keep the glaze thickness at 1 to 1.5 mm. (6) Dry the glazed body for at least 30 minutes; (7) The dried green body is fired in an oxidizing atmosphere according to the following temperature profile: First stage: Raise the temperature from room temperature to 390-410℃ over 170 minutes, and then hold the temperature for 20 minutes; Second stage: Increase the temperature from 390-410℃ to 590-610℃ over 100 minutes, and then hold the temperature for 20 minutes; The third stage: the temperature is increased from 590-610℃ to 1110-1120℃, and the heating time is 210 minutes; The fourth stage involves raising the temperature from 1110℃~1120℃ to 1220℃~1230℃ over a period of 40 minutes. Fifth stage: Cool down from 1220℃~1230℃ to 1050℃ for 170 minutes, and then keep warm at 1050℃ for 90~120 minutes; Finally, stop heating and let the furnace cool to room temperature to obtain the final product.

2. The method for preparing ceramic raw material tea dust glaze according to claim 1, characterized in that, The vanadium-titanium magnetite mentioned in step (1) contains 63.00% to 63.05% Fe3O4, 6.79% to 6.84% TiO2, and 0.13% to 0.18% V2O5; preferably, the vanadium-titanium magnetite also contains 0.46% to 0.49% MnO and 0.033% to 0.035% Cr2O3.

3. The method for preparing ceramic raw material tea dust glaze according to claim 1, characterized in that, The particle size of the various raw materials mentioned in step (1) is greater than 120 mesh.

4. The method for preparing ceramic raw material tea dust glaze according to claim 1, characterized in that, In the formula of step (1), the percentage content ratio of Fe3O4, ZnO and TiO2 is 3.40~3.78∶1.98~2.00∶1.41~1.

69.

5. The method for preparing ceramic raw material tea dust glaze according to claim 1, characterized in that, In step (2), the ball milling ratio of material:ball:water is 1:1.8~2.0:0.8~1.2, and the ball milling time is 10~12 minutes; the preferred ball milling speed is 83 r / min.

6. The method for preparing ceramic raw material tea dust glaze according to claim 1, characterized in that, In step (7): The heating rate in the first stage is 2.06–2.18 °C / min; The heating rate in the second stage is 1.80–2.20 °C / min; The heating rate in the third stage is 2.38–2.52 °C / min; The heating rate in the fourth stage is 2.50–3.00 °C / min; The cooling rate in the fifth stage is 1.00–1.06 °C / min.

7. A ceramic raw material tea dust glaze, characterized in that, It is prepared by the method described in any one of claims 1 to 6.

8. The ceramic raw material tea dust glaze according to claim 7, characterized in that, Its color difference L value is 28.23~41.16, a value is 5.24~6.82, b value is 13.42~19.14; its gloss is 19.42~32.51; its blue light whiteness is 2.52%~3.71%.

9. The ceramic raw material tea dust glaze according to claim 7, characterized in that, Its scratch resistance is grade 1, its thermal shock resistance index is 147-160℃ with a standard deviation of 0-16.3℃, and its chemical corrosion resistance is grade III.

10. A ceramic product, characterized in that, Its surface is coated with the ceramic raw material tea dust glaze as described in any one of claims 7 to 9.

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