Purple pottery with high thermal shock resistance and preparation method thereof

Abstract

The invention discloses purple pottery with high thermal shock resistance, and relates to the field of structural ceramics, the purple pottery with high thermal shock resistance comprises the following main components in percentage by mass: 70-90% of Jianshui pottery clay and 10-30% of quartz powder, and the purple pottery with high thermal shock resistance is divided into white mud purple pottery and red mud purple pottery. The invention further discloses a method for preparing the purple pottery with the high thermal shock resistance. The method comprises the steps of slurry preparation, material addition, slurry drying and refining and adobe manufacturing and sintering. The purple pottery with high thermal shock resistance prepared by the invention can bear 50 times of heat exchange in water at 200-370 DEG C to 20 DEG C, does not crack, has stable water boiling performance when being heated by open fire, and has the same surface smoothness as that of traditional purple pottery which is polished to be bright as a mirror. According to the invention, the quartz powder with low price is added into the traditional Jianshui purple pottery material, so that the thermal shock resistance of the Jianshui purple pottery is enhanced and the cost is reduced on the premise of keeping the traditional characteristic process characteristics.

Description

Technical Field

[0001] The invention relates to the field of structural ceramics, in particular to purple pottery with high thermal shock resistance and a preparation method thereof. Background Art

[0002] Jianshui purple pottery, one of China's four famous ceramics, boasts a unique intaglio and embossing technique, along with an unglazed polished finish, which allows it to express itself artistically. However, poor thermal shock resistance is a key issue facing this traditional material and is in urgent need of improvement. According to the Yunnan Provincial Standard for Thermal Shock Resistance Testing (DB53 / T 559-2019, a Geographical Indication Product of Jianshui Purple Pottery), small-sized traditional Jianshui purple pottery requires a single heat exchange between 180°C and 20°C without cracking, while medium, large, and special-sized products require a single heat exchange between 160°C and 20°C without cracking. Currently, traditional Jianshui purple pottery cannot withstand a single heat exchange between 200°C and 20°C without cracking. This limits its primary use to tea sets, decorative items, and low-temperature cooking utensils.

[0003] Among everyday ceramics, ceramics with good thermal shock resistance have a wider range of uses. For example, ceramic bowls used in Yunnan cross-bridge rice noodles require thermal shock resistance to withstand multiple heat exchanges in water between 200°C and 80°C without cracking. Ceramics used as traditional Chinese medicine jars and teapots, which are heated over open flames, require even higher thermal shock resistance.

[0004] The published patent application number CN202210440244 for Jianshui purple pottery with high thermal shock resistance investigates the use of kaolin, spodumene, and cordierite to improve the thermal shock resistance of Jianshui purple pottery. This patented invention significantly improves the thermal shock resistance of traditional Jianshui purple pottery, enabling it to withstand temperatures up to 600°C, a significant improvement in the thermal shock resistance of Jianshui purple pottery vessels. However, this patented invention fails to incorporate the characteristic unglazed finish of traditional Jianshui purple pottery, which achieves a mirror-like smoothness and jade-like finish after polishing. Furthermore, the kaolin, spodumene, and cordierite used in this invention are all commonly used raw materials for thermal shock-resistant ceramics in industry, but these three raw materials account for more than 60% of the formula, making the clay of Jianshui purple pottery essentially the same as the ingredients. Moreover, it has not been mentioned that it has the characteristics of traditional Jianshui purple pottery that after polishing it is as bright as a mirror and as smooth as jade.

[0005] Therefore, technicians in this field are committed to developing a purple pottery with high thermal shock resistance and its preparation method, while maintaining its characteristics of being able to be engraved and filled, and being as bright as a mirror and as smooth as jade after polishing, to improve the thermal shock resistance of traditional Jianshui purple pottery and expand its application in high-temperature heating appliances. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is that the traditional Jianshui purple pottery has poor thermal shock resistance and improving the thermal shock resistance requires sacrificing the most distinctive unglazed polished feature of Jianshui purple pottery.

[0007] To achieve the above-mentioned object, the present invention provides purple pottery with high thermal shock resistance. The main components of the purple pottery with high thermal shock resistance are as follows: 70% to 90% Jianshui clay and 10% to 30% quartz powder in percentage by weight. The purple pottery with high thermal shock resistance is divided into white clay purple pottery and red clay purple pottery. The purple pottery with high thermal shock resistance can withstand 50 heat exchanges in water at 20°C to 370°C without cracking, and has stable performance in boiling water heated by open flame.

[0008] Furthermore, the main components of the white mud purple pottery are as follows: 49% to 63% white mud clay, 21% to 27% green clay, and 10% to 30% quartz powder by weight.

[0009] Furthermore, the main components of the red clay purple pottery are as follows by mass percentage: 38.5% to 49.5% of Wuhua soil, 14% to 18% of white mud soil, 10.5% to 13.5% of green soil, 3.5% to 4.5% of loess, 2.1% to 2.7% of purple soil, and 10% to 30% of quartz powder.

[0010] Furthermore, the mesh size of the quartz powder is 100-325 meshes, and the average particle size of the Jianshui clay is 6-10 μm.

[0011] The present invention also provides a method for preparing purple pottery with high thermal shock resistance, the method comprising the following steps:

[0012] Step 1, mud preparation: weigh Jianshui clay according to the mass percentage of the components, add it into a slurry pool filled with water and soak it for 5 to 12 hours, then stir it to form a mud containing impurities, and then filter the mud with a sieve to remove impurities;

[0013] Step 2, material addition: add water to the quartz powder and stir evenly, then pour it into the stirring mud that has been sieved and filtered to remove impurities, so that the quartz powder is evenly dispersed in the mud;

[0014] Step 3, mud drying and refining: the mud with quartz powder added is put into a bag and air-dried using existing technology or filtered by a filter press to remove water, so that the mud is air-dried into wet mud; the wet mud after air drying or filtering is refined in a vacuum mud mill to remove the gas in the clay and mix the dry and wet parts of the mud evenly;

[0015] Step 4, making and sintering adobe: The prepared clay is made into a green body by using existing technology, i.e., throwing or machine pressing. After the green body is air-dried, it is decorated and repaired as needed. The air-dried green body is then sintered and naturally cooled to room temperature.

[0016] Furthermore, the step 1 is specifically as follows: water is added to the slurry pool in advance, and then Jianshui clay is added, and the mass of the added water is 3 times the mass of the clay; during the stirring process of the clay after soaking, if there are water-insoluble hard particles, they need to be removed; the stirring time in the step 1 is 15 to 30 minutes, the stirring speed is 750 r / min, and the mesh size of the sieve is 200 mesh or 250 mesh.

[0017] Furthermore, in step 2, the mass ratio of quartz powder to water is 1:1. The quartz is added to water and stirred for 15 to 30 minutes before being poured into the stirred slurry. The quartz powder is a quartz powder with a low thermal expansion coefficient, selected from one of quartz fiber powder, quartz glass powder, fused quartz powder, and quartz powder.

[0018] Furthermore, the moisture content of the wet mud after air drying or filter pressing in step 3 is 15-30%; the vacuum pumping times during the mud refining process is 2-4 times, the vacuum degree is 0.08-0.09 MPa, and the final moisture content of the mud is 20-25%.

[0019] Furthermore, the sintering process of the air-dried green body in step 4 is as follows: a heating rate of 1 to 2°C / min, a sintering temperature of 1155 to 1180°C for red clay green body, a sintering temperature of 1190 to 1240°C for white clay green body, a holding time of 15 to 30 minutes, and natural cooling to room temperature after the holding period.

[0020] The surface of the purple pottery with high thermal shock resistance can be polished to a mirror-like finish.

[0021] The invention also discloses the application of purple pottery with high thermal shock resistance, which is used in high-temperature tableware, teapots, Chinese medicine pots or ceramic electrical appliance industries.

[0022] By adding quartz powder to Jianshui purple pottery, this invention leverages the quartz particles' low thermal expansion coefficient and strong heat resistance to create a porous structure within the pottery during sintering. This provides a buffer for thermal expansion and contraction during rapid cooling from high temperatures, significantly enhancing the pottery's thermal shock resistance. While retaining the traditional Jianshui purple pottery's characteristic intaglio-filled decorative elements and unglazed polished surface finish, this invention improves the pottery's thermal shock resistance and expands its applications in Jianshui purple pottery cross-bridge rice noodle bowls, Jianshui purple pottery traditional Chinese medicine pots, and practical utensils.

[0023] In a preferred embodiment of the present invention, purple pottery with high thermal shock resistance is used in Jianshui purple pottery cross-bridge rice noodle bowls, Jianshui purple pottery teapots, Jianshui purple pottery Chinese medicine pots, Jianshui purple pottery ceramic electrical appliance industry, etc.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] 1. The present invention greatly enhances the thermal shock resistance of Jianshui purple pottery by adding a small amount of quartz powder to traditional Jianshui purple pottery. Taking advantage of the low thermal expansion coefficient and strong temperature resistance of quartz powder, a certain pore structure is created inside the Jianshui purple pottery during the sintering process of the Jianshui purple pottery clay. This provides a certain buffer space for the thermal expansion and contraction of the material during the process of rapid cooling from high temperature, greatly enhancing the thermal shock resistance of the Jianshui purple pottery. Traditional Jianshui purple pottery has poor thermal shock resistance and can only withstand a single heat exchange from 180°C to 20°C without cracking. The Jianshui purple pottery of the present invention can be immersed in room temperature water at 200°C for more than 50 times without cracking, and can also be heated over an open flame. This expands its application in practical high-temperature utensils such as Jianshui purple pottery cross-bridge rice noodle bowls and Jianshui purple pottery Chinese medicine pots.

[0026] 2. This invention significantly improves the thermal shock resistance of Jianshui purple pottery while also taking into account the traditional craftsmanship characteristics of unglazed polishing and intaglio-filling. Analysis revealed that the average volume diameter of Jianshui purple pottery clay is 6-10 μm, indicating relatively fine particles. Therefore, the present invention grinds the added quartz powder to a mesh size that matches the particle size of Jianshui purple pottery. This results in a surface roughness similar to that of traditional Jianshui purple pottery after the addition of quartz powder. This also ensures that the addition of high-mesh materials significantly improves the thermal shock resistance of Jianshui purple pottery. This improves the thermal shock resistance of traditional Jianshui purple pottery while maintaining its characteristics of intaglio-filling and mirror-like brightness and jade-like smoothness after polishing.

[0027] 3. The high-thermal-shock-resistant material developed by this invention is low-cost and utilizes Jianshui purple pottery clay as its primary raw material to enhance its performance. While existing technologies have improved the thermal-shock resistance of Jianshui purple pottery, they incorporate a significant amount of expensive materials, exceeding 60%, significantly increasing material costs and negating the essential properties of Jianshui purple pottery. The quartz powder added to the purple pottery by this invention is inexpensive and is added in low quantities, while the primary raw material remains Jianshui purple pottery clay.

[0028] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The red clay purple pottery with high thermal shock resistance prepared in Example 1 of the present invention;

[0030] Figure 2 The white clay purple pottery with high thermal shock resistance prepared in Example 1 of the present invention;

[0031] Figure 3 The red clay purple pottery with high thermal shock resistance prepared in Example 2 of the present invention;

[0032] Figure 4 The white clay purple pottery with high thermal shock resistance prepared in Example 2 of the present invention;

[0033] Figure 5 The white clay purple pottery with high thermal shock resistance prepared in Example 3 of the present invention;

[0034] Figure 6 The high thermal shock resistance red clay purple pottery prepared in Example 4 of the present invention;

[0035] Figure 7 This is the red clay purple pottery with high thermal shock resistance prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0036] The following describes several preferred embodiments of the present invention with reference to the accompanying drawings to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0037] Example 1

[0038] Weigh 25kg each of the clay used to prepare white and red clay for purple pottery, pour them into two separate slurry tanks filled with water, let them stand for 12 hours, and then stir to prepare uniform white and red clay slurries. The slurries are then filtered through a 250-mesh sieve to remove impurities. Weigh 6.25kg each of two 150-250 mesh quartz powders, add a small amount of water to dissolve them evenly, stir for 30 minutes, and then pour them into the stirring slurries to evenly disperse the quartz powders. The slurries with added quartz powders are then placed in a cloth bag and air-dried to remove water, resulting in wet clay with a moisture content of 25%. The wet clay is refined in a vacuum kneader to remove any air from the clay and evenly mix the dry and wet contents of the clay, resulting in a final moisture content of 20%. Adobe bricks are made by throwing, air-dried, and then trimmed. The trimmed bricks are air-dried and then sintered. Red clay bricks are fired to 1155°C at a heating rate of 1.83°C / min; white clay bricks are fired to 1210°C at a heating rate of 1.89°C / min. Both are held at this temperature for 20 minutes, followed by natural cooling to room temperature. After sintering, the red clay purple pottery is polished to a matte finish, while the white clay purple pottery is polished to a gloss finish.

[0039] Prepared high thermal shock resistance red clay purple pottery Figure 1 As shown, the thermal shock resistance of white clay purple pottery is as follows Figure 2 shown.

[0040] The thermal shock resistance of the purple pottery samples produced according to the present invention was measured with reference to the GB / T3298-2008 standard, "Determination of Thermal Shock Resistance of Household Ceramics." A purple pottery bowl sample (20 cm in diameter and 8 cm in height) from Example 1 was placed in an oven and heated to different test temperatures (starting at 200°C and increasing by 10°C, i.e., a gradient of test temperatures, from 200°C to 370°C). The bowl was then immersed in room temperature water and then poured with room temperature water. The bowl was then observed for damage or cracking. The experimental results are shown in Table 1.

[0041] Table 1 Thermal shock test results of purple pottery bowls

[0042] sample 200℃ test damage Sample damage during the test at 200℃-370℃ Red mud samples No damage No damage White clay samples No damage No damage

[0043] Take the purple pottery roasted tea pot sample of Example 1 (diameter 9 cm, height 8 cm), add room temperature water, then place the sample pot on an open flame for heating, boil the water until it boils, observe whether the sample is damaged or cracked during this process, and repeat the process many times (the process was repeated 50 times in this experiment), and the sample was not damaged or cracked.

[0044] The high thermal shock resistance purple pottery prepared in Example 1 can withstand 50 heat exchanges in water from 370°C to 20°C without cracking, and has stable performance when heated with an open flame to boil water.

[0045] Example 2

[0046] Weigh 25 kg of clay for preparing purple pottery white mud and purple pottery red mud respectively, pour them into two slurry pools filled with water, let them stand for 12 hours and then stir to prepare uniform white mud slurry and red mud slurry, weigh two parts of 100-150 mesh quartz powder 6.25 kg each, add a small amount of water to dissolve them evenly, and then pour them into the stirring mud to evenly disperse the quartz powder, put the mud with added quartz powder into a cloth bag, air-dry and remove water to obtain wet mud, refine the wet mud with a vacuum mud kneading machine to remove the air in the clay and mix the overall dryness and humidity of the mud evenly, make adobe by throwing, repair the adobe after air drying, and sinter the repaired adobe after drying (red mud adobe is fired to 1180°C and white mud adobe is fired to 1190°C), the heating rate is 1°C / min, the sintering holding time is 15 min, and it is naturally cooled to room temperature after the insulation is completed.

[0047] Prepared high thermal shock resistance red clay purple pottery Figure 3 As shown, high thermal shock resistance white clay purple pottery Figure 4 As shown, the high thermal shock resistance purple pottery prepared in Example 2 can withstand 50 heat exchanges in water from 370°C to 20°C without cracking, and has stable performance in boiling water under open flame heating, but the sample surface is rougher than the sample prepared in Example 1.

[0048] Example 3

[0049] Weigh 25 kg of pottery clay for preparing purple pottery and white mud, pour it into a slurry pool filled with water, let it stand for 12 hours and then stir to prepare a uniform slurry, weigh 2.78 kg of 100-150 mesh quartz powder, add a small amount of water to dissolve it evenly, and then pour it into the stirring white mud slurry to disperse the quartz powder evenly, put the mud with added quartz powder into a cloth bag, air-dry and remove water to obtain wet mud, refine the wet mud with a vacuum mud kneader to remove the air in the pottery clay and mix the overall dryness and wetness of the mud evenly, make adobe by throwing, repair the adobe after air drying, and sinter the repaired adobe after drying (red clay adobe is fired to 1155°C and white clay adobe is fired to 1240°C), the heating rate is 1.83°C / min, the sintering holding time is 30 min, and it is naturally cooled to room temperature after the insulation is completed.

[0050] The prepared red clay purple pottery with high thermal shock resistance is shown in the figure, and the white clay purple pottery with high thermal shock resistance is shown in the figure. Figure 5 As shown, the high thermal shock resistance purple pottery prepared in Example 3 can withstand 50 heat exchanges in water from 340°C to 20°C without cracking.

[0051] Example 4

[0052] Weigh 25 kg of clay for preparing purple pottery red mud, pour it into a slurry pool filled with water, let it stand and soak for 5 hours, then stir to prepare a uniform red mud slurry, weigh 10.71 kg of 325 mesh quartz powder, add a small amount of water to dissolve it evenly, and then pour it into the stirring red mud slurry to disperse the quartz powder evenly, put the mud with added quartz powder into a cloth bag, air-dry and remove water to obtain wet mud, refine the wet mud with a vacuum mud kneading machine to remove the air in the clay and mix the overall dryness and wetness of the mud evenly, make adobe by throwing, air-dry the adobe and then repair it, dry the repaired body and sinter it to 1155°C, the sintering and heat preservation time are 30 minutes, and naturally cool to room temperature after the end of the heat preservation, and then perform bright polishing.

[0053] Prepared high thermal shock resistance red clay purple pottery Figure 6 As shown, the high-thermal-shock-resistant purple pottery prepared in Example 4 can withstand up to 50 heat exchanges in water between 200°C and 20°C without cracking. Compared to the purple pottery samples prepared in Examples 1, 2, and 3, the purple pottery sample prepared in Example 4 has a smoother surface and better thermal-shock-resistant properties than the purple pottery sample prepared in Example 5.

[0054] Example 5

[0055] Weigh 25 kg of clay for preparing purple pottery red mud, pour it into a slurry pool filled with water, let it stand for 12 hours and then stir to prepare a uniform red mud slurry, weigh 6.25 kg of 325 mesh quartz powder, add a small amount of water to dissolve it evenly, and then pour it into the stirring red mud slurry to disperse the quartz powder evenly, put the mud with added quartz powder into a cloth bag, air-dry and remove water to obtain wet mud, refine the wet mud with a vacuum mud kneading machine to remove the air in the clay and mix the overall dryness and wetness of the mud evenly, make adobe by throwing, air-dry the adobe and then repair it, dry the repaired body and sinter it to 1155°C, the sintering and heat preservation time are 15 minutes, and then naturally cool to room temperature after the end of the heat preservation.

[0056] Prepared high thermal shock resistance red clay purple pottery Figure 7 As shown, the high thermal shock resistance purple pottery prepared in Example 5 can withstand up to 50 heat exchanges in water from 200°C to 20°C without cracking. Compared with the purple pottery samples prepared in Examples 1, 2, 3, and 4, the purple pottery sample prepared in Example 5 has the smoothest surface.

[0057] The preferred embodiments of the present invention have been described in detail above. It should be understood that numerous modifications and variations based on the concepts of the present invention are possible without inventive effort by those skilled in the art. Therefore, any technical solution that can be derived by one skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A purple pottery with high thermal shock resistance, characterized in that: The main components of the purple pottery with high thermal shock resistance are 70% to 90% Jianshui clay and 10% to 30% quartz powder in percentage by weight. The purple pottery with high thermal shock resistance is divided into white clay purple pottery and red clay purple pottery. The purple pottery with high thermal shock resistance can withstand 50 heat exchanges in water from 200 to 370°C to 20°C without cracking, and has stable performance when heated with an open flame to boil water.

2. The purple pottery with high thermal shock resistance according to claim 1, characterized in that: The main components of the white mud purple pottery are as follows: 49% to 63% white mud clay, 21% to 27% green clay, and 10% to 30% quartz powder in percentage by weight.

3. The purple pottery with high thermal shock resistance according to claim 1, characterized in that: The main components of the red clay purple pottery are as follows: 38.5% to 49.5% of five-flowered soil, 14% to 18% of white mud soil, 10.5% to 13.5% of green soil, 3.5% to 4.5% of loess, 2.1% to 2.7% of purple soil, and 10% to 30% of quartz powder in percentage by weight.

4. The purple pottery with high thermal shock resistance according to claim 1, characterized in that: The mesh number of the quartz powder is 100-325 meshes, and the average particle size of the Jianshui clay is 6-10 μm.

5. A method for preparing purple pottery with high thermal shock resistance as claimed in claims 1 to 4, characterized in that: The method comprises the following steps: Step 1, mud preparation: weigh Jianshui clay according to the mass percentage of the components, add it into a slurry pool filled with water and soak it for 5 to 12 hours, then stir it to form a mud containing impurities, and then filter the mud with a sieve to remove impurities; Step 2, material addition: first add quartz powder to water and stir evenly, then pour it into the stirring mud that has been sieved and filtered to remove impurities, so that the quartz powder is evenly dispersed in the mud; Step 3, mud drying and refining: the mud with quartz powder added is put into a bag and air-dried using existing technology or filtered by a filter press to remove water, so that the mud is air-dried into wet mud; the wet mud after air drying or filtering is refined in a vacuum mud mill to remove the gas in the clay and mix the dry and wet parts of the mud evenly; Step 4, making and sintering adobe: The prepared clay is made into a green body by using existing technology, i.e., throwing or machine pressing. After the green body is air-dried, it is decorated and repaired as needed. The air-dried green body is then sintered and naturally cooled to room temperature.

6. The method for preparing purple pottery with high thermal shock resistance according to claim 5, characterized in that: The step 1 specifically comprises: adding water to the slurry pool in advance, and then adding Jianshui clay, with the mass of the added water being 3 times the mass of the clay; during the stirring process of the clay after soaking, if there are any hard particles insoluble in water, they need to be removed; the stirring time in the step 1 is 15 to 30 minutes, the stirring speed is 750 r / min, and the mesh size of the sieve is 200 mesh or 250 mesh.

7. The method for preparing purple pottery with high thermal shock resistance according to claim 5, characterized in that: In step 2, the mass ratio of quartz powder to water is 1:

1. The quartz is added to water and stirred for 15 to 30 minutes, and then poured into the stirred slurry. The quartz powder is a quartz powder with a low thermal expansion coefficient, selected from one of quartz fiber powder, quartz glass powder, fused quartz powder, and quartz powder.

8. The method for preparing purple pottery with high thermal shock resistance according to claim 5, wherein: The moisture content of the wet mud after air drying or filter pressing in step 3 is 15-30%; the vacuum pumping times during the mud refining process is 2-4 times, the vacuum degree is 0.08-0.09 MPa, and the final moisture content of the mud is 20-25%.

9. The method for preparing purple pottery with high thermal shock resistance according to claim 5, wherein: The sintering process of the air-dried green body in step 4 is as follows: a heating rate of 1-2°C / min, a sintering temperature of 1155-1180°C for red clay green body, a sintering temperature of 1190-1240°C for white clay green body, a holding time of 15-30min, and natural cooling to room temperature after the holding is completed.

10. An application of purple pottery with high thermal shock resistance, characterized in that: The purple pottery with high thermal shock resistance is applied to high-temperature tableware, teapots, Chinese medicine pots or ceramic electrical appliance industries.

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