Preparation method of modified purple pottery product with high-brightness texture

Abstract

The invention relates to a preparation method of a modified purple pottery product with high-brightness texture, which comprises the following steps: adding a certain proportion of micron-sized magnesium oxide powder into Jianshui pottery clay, and adding water to control the viscosity and water content of the pottery clay; the blank is drawn and formed into any shape; or adding sodium silicate nonahydrate powder and micron-sized magnesium oxide powder into the Jianshui purple pottery slurry, adding water to control the viscosity and fluidity of the pottery slurry, and performing slip casting to form any shape; and drying, calcining, preserving heat and cooling to room temperature to form a purple pottery product. The prepared purple pottery product is glossy in surface, easy to clean, free of dirt and capable of generating natural jade texture, compared with a traditional purple pottery product at present, the purple pottery product can have the surface gloss only after being polished or glazed, the processing procedures are reduced, and therefore the processing cost and energy consumption are reduced, magnesium is a health element necessary for the human body, and the production cost is reduced. Therefore, the product form of the purple pottery is expanded, and the commercial value of the Jianshui purple pottery is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramics, and in particular relates to a preparation method of a modified purple pottery product with high-brightness texture. Background Art

[0002] Jianshui purple pottery is a traditional daily-use ceramic produced in Jianshui County, Yunnan Province. It is currently mainly used as tea sets, decorative ornaments, cooking utensils, etc. At present, purple pottery products are mainly black, white, and red. The surface texture of non-wood-fired and unpolished purple pottery products is relatively simple. At present, the way to obtain the gloss on the surface of purple pottery products is generally polished. Unglazed polishing is one of the major characteristics of Jianshui purple pottery, but the cost and price of polished products are also higher than those of unpolished products. Due to its appearance characteristics and price, the use scenarios of traditional Jianshui purple pottery are subject to many restrictions.

[0003] In the field of building materials, magnesium oxide is generally believed to be able to enhance the porcelain texture of tiles. However, since the particle size of Jianshui purple pottery clay is finer than other traditional ceramic clays, the surface porcelain texture formed after conventional magnesium oxide powder is added to purple pottery is uneven. Moreover, too much magnesium oxide powder added will cause the original texture of the purple pottery to be covered, while too little will result in the surface having no obvious high-gloss texture. Summary of the invention

[0004] The inventor uses cement slurry as a raw material and magnesium oxide as an additive to prepare a modified purple pottery product with a high-brightness texture through wheel throwing or slip injection molding, thereby completing the present invention.

[0005] Therefore, in a first aspect, the present invention provides a method for preparing a purple pottery product, the method comprising:

[0006] 1) Weighing cement slurry, adding 5%-30% of the dry weight of the slurry to the slurry, and refining the slurry to obtain slurry material after drying;

[0007] 2) kneading the clay material evenly, squeezing out bubbles, and forming the clay material into a green body by wheel throwing, and trimming the green body after it is half dry;

[0008] 3) drying the green body, raising the temperature to a sintering temperature, maintaining the temperature at the sintering temperature for 20 minutes, and then cooling to room temperature to obtain a purple pottery product.

[0009] In some embodiments, in step 1), the Jianshui mud is made of clay raw materials in Jianshui County, Yunnan Province, including red mud and white mud, wherein the red mud is generally prepared from 50% five-color soil, 15% loess, 5% white clay, 10% blue soil, and 10% purple soil, and the white mud is generally prepared from 65% white clay and 35% blue soil. In a preferred embodiment, a sieve with a mesh size of 200-300 is used for filtering when making the mud.

[0010] In some embodiments, in step 1), the purity of the added magnesium oxide powder should be 98% wt. or above, and the dry weight of the added magnesium oxide powder accounts for 5% to 30% of the dry weight of the mud. When the added amount is less than 5%, it is difficult to see the glassy layer on the surface of the produced purple pottery product, and the surface glossiness is limited. When the added amount is greater than 30%, the purple pottery itself in the mud is relatively small, and the physical properties of the purple pottery product are greatly changed. The surface of the produced purple pottery bowl has more glassy layers. Although the glossiness is more significantly improved, the effect is similar to that of adding glaze, but the texture of the purple pottery itself is lost, and the increase in the amount added will also increase the cost.

[0011] In some embodiments, in step 2), the blank may be in any shape.

[0012] In some embodiments, in step 3), the sintering temperature is related to the type of clay material. The sintering temperature of red clay is 1150°C, and the sintering temperature of white clay is 1200°C.

[0013] In a second aspect, the present invention provides another method for preparing a purple pottery product, the method comprising:

[0014] 1) Weighing cement slurry, the water content of which is controlled at 30%-40%, preferably about 35%, adding sodium silicate nonahydrate powder accounting for 0.5%-5.0% of the mass fraction of the solid content of the slurry and micron-grade magnesium oxide powder accounting for 5%-30% of the mass fraction of the solid content of the slurry, and stirring to form slurry;

[0015] 2) Inject the slurry into the plaster mold, keep it for 30-120 seconds, pour out the wet slurry, demould it after drying, and repair the blank;

[0016] 3) After the green body is dried, the temperature is raised to the sintering temperature, kept at the sintering temperature for about 20 minutes, and then cooled to room temperature.

[0017] In some embodiments, in step 1), the purple pottery mud needs to be filtered through a sieve with a mesh size of 60 or more, and the water content of the mud when weighed needs to reach 30%-40%; the purity of the sodium silicate nonahydrate powder and the magnesium oxide powder should be 98% or more. Further, the dry weight of the sodium silicate nonahydrate powder relative to the solid content of the entire mud should be 0.5-5.0%. The addition of sodium silicate nonahydrate is used to improve the fluidity of the mud. When the amount added is too little, in the step of pouring out the excess mud, due to the poor fluidity of the mud, the amount of mud retained in the gypsum mold is large and uneven, the purple pottery bowl blank produced is uneven, and the finished product after firing occasionally cracks; when the amount added is too much, the fluidity of the mud is very strong but the viscosity is poor. The mud needs to be kept in the gypsum mold for a longer time to ensure that it has a sufficient thickness to support the structure of the blank itself, and due to the insufficient viscosity, the influence of gravity is more obvious, and the lower layer of the blank will be thicker than the upper layer of the blank, resulting in uneven overall quality of the blank.

[0018] In some embodiments, in step 2), the drying time is at least 2 hours.

[0019] In some embodiments, in step 3), the sintering temperature is related to the type of clay material. The sintering temperature of red clay is 1150°C, and the sintering temperature of white clay is 1200°C.

[0020] In a third aspect, the present invention provides a purple pottery product obtained by the above preparation method, wherein the purple pottery product has a high-gloss texture. The "high-gloss texture" described herein is relative to conventional purple pottery products that have not been polished or otherwise modified.

[0021] In some embodiments, a glassy layer can be observed on the surface of the purple pottery product with high gloss texture prepared by the present invention, and the product has a good easy-to-clean effect.

[0022] Technical Effects

[0023] The present invention uses magnesium oxide as an additive to develop a modified purple pottery product with a high-brightness texture. Compared with the two current methods of changing the surface texture of purple pottery products, namely, wood burning and polishing, the present invention has the advantages of simple production method, low cost and high yield. The purple pottery product produced by the present invention can adjust the glossiness of the surface according to the content of the added magnesium oxide, and magnesium is a healthy element required by the human body, which expands the form of purple pottery products and the application market of purple pottery. Compared with wood burning and polishing, the present invention has less energy consumption and has important application value for sustainable development.

[0024] The addition of magnesium oxide often makes ceramic products show a porcelain texture. However, when magnesium oxide powder is directly added to purple pottery clay, there will be a problem of uneven mixing, resulting in a high magnesium oxide content in the local part of the purple pottery body, and the uniformity of the glassy layer on the surface of the fired purple pottery is not good, and the transparency of the surface glassy layer is insufficient. The inventor has found through research that when micron-grade (particle size is 1-10 microns) magnesium oxide is added to the purple pottery clay, the surface of the Jianshui purple pottery product has a uniform high-gloss texture, while the surface brightness of the purple pottery product added with coarse magnesium oxide powder (particle size greater than 100 microns) is uneven, and does not have a complete high-gloss texture. This may be because the clay of Jianshui purple pottery has a finer particle size. Therefore, adding finer magnesium oxide powder can make it more evenly mixed with the clay.

[0025] In addition, magnesium oxide powder is non-toxic and harmless and will not cause harm to the human body. Its presence in purple pottery clay can improve the thermal shock resistance and toughness of purple pottery products. Jianshui pottery clay also does not contain harmful substances and will not produce substances harmful to the human body during the sintering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a photo of a purple pottery bowl with a high gloss texture prepared in Example 1;

[0027] Figure 2 This is a photo of a purple pottery bowl with a high gloss texture prepared in Example 2;

[0028] Figure 3 This is a photo of a purple pottery bowl with a high gloss texture prepared in Example 3;

[0029] Figure 4 The photos are of purple pottery bowls with high gloss texture prepared in Example 2 (left) and Example 3 (right);

[0030] Figure 5 This is a photo of the purple pottery bowl with a high gloss texture prepared in Example 1 after being cleaned and dried in the oil drop experiment in Experimental Example 1;

[0031] Figure 6 This is a photograph of a traditional purple pottery bowl after being cleaned and dried in the oil drop experiment in Experimental Example 1. DETAILED DESCRIPTION

[0032] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0033] The magnesium oxide powders used in the following Examples 1-8 and Comparative Examples 1-4 are all micron-grade magnesium oxide powders with a particle size of 1-10 microns.

[0034] Example 1

[0035] Steps: weigh Jianshui white mud, filter it through a 200-300 mesh screen, add 10%wt. magnesium oxide powder into the mud, filter it and knead it into mud material, and the moisture content of the mud material after kneading is about 25%.

[0036] The clay is formed into a bowl shape by wheel throwing, with an outer diameter of 17.5 cm, a height of 5.7 cm and a thickness of 1 cm. After wheel throwing, the clay is trimmed and dried at room temperature for 24 hours.

[0037] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0038] Photos of purple pottery products formed by wheel throwing Figure 1 shown.

[0039] Example 2

[0040] Steps: weigh Jianshui white mud, filter it through a 200-300 mesh screen, add 5% magnesium oxide powder into the mud, filter it and knead it into mud material. The moisture content of the mud material after kneading is about 25%.

[0041] The clay is formed into a bowl shape by wheel throwing, with an outer diameter of 17.5 cm, a height of 5.7 cm and a thickness of 1 cm. After wheel throwing, the clay is trimmed and dried at room temperature for 24 hours.

[0042] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0043] Example 3

[0044] Steps: weigh Jianshui white mud, filter it through a 200-300 mesh screen, add 30% magnesium oxide powder into the mud, filter it and knead it into mud material. The moisture content of the mud material after kneading is about 25%.

[0045] The clay is formed into a bowl shape by wheel throwing, with an outer diameter of 17.5 cm, a height of 5.7 cm and a thickness of 1 cm. After wheel throwing, the clay is trimmed and dried at room temperature for 24 hours.

[0046] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0047] Example 4

[0048] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 9.21g (5%wt.) of magnesium oxide powder.

[0049] 1.86 g (1% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0050] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0051] Turn the plaster mold upside down and pour out the undried mud in the plaster mold. Then let the plaster mold stand for five hours, demould it, and take out the purple pottery body for repair.

[0052] After the green body is dried, the temperature is raised to a sintering temperature (1200° C.), kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0053] Photos of purple pottery products made by injection molding Figure 2 shown.

[0054] Example 5

[0055] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 19.44g (10%wt.) of magnesium oxide powder.

[0056] 1.96 g (1% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0057] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0058] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0059] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0060] Photos of purple pottery products made by injection molding Figure 3 shown.

[0061] Example 6

[0062] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 75g (30%wt.) of magnesium oxide powder.

[0063] 2.53 g (1% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0064] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0065] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0066] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0067] Example 7

[0068] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 19.44g (10%wt.) of magnesium oxide powder.

[0069] 0.98 g (0.5% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0070] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0071] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0072] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0073] Example 8

[0074] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 19.44g (10%wt.) of magnesium oxide powder.

[0075] 10.23 g (5% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0076] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0077] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0078] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0079] Comparative Example 1

[0080] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 94.23g (35%wt.) of magnesium oxide powder.

[0081] 2.72 g (1% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0082] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0083] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0084] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0085] Comparative Example 2

[0086] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 5.41g (3%wt.) of magnesium oxide powder.

[0087] 1.82 g (1% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0088] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0089] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0090] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0091] Comparative Example 3

[0092] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 19.44g (10%wt.) of magnesium oxide powder.

[0093] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0094] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0095] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0096] Comparative Example 4

[0097] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 19.44g (10%wt.) of magnesium oxide powder.

[0098] 21.60 g (10% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0099] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0100] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0101] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0102] Comparative Example 5

[0103] Steps: Control the water content of Jianshui white mud to about 35%, weigh 500g of mud, and add 19.44g (10%wt.) of coarse magnesium oxide powder (average particle size>100 microns).

[0104] 1.96 g (1% wt.) sodium silicate nonahydrate was added with stirring to modify the rheology of the slurry.

[0105] Pour the slip into the plaster mold and allow the slip to remain in the mold for 90 seconds.

[0106] Turn the plaster mold upside down, pour out the mud in the plaster mold, then let the plaster mold stand for five hours, demould it, take out the purple pottery body and repair it.

[0107] After the green body is dried, the temperature is raised to 1200° C., kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0108] Example 4 is compared with Example 5 ( Figure 4 , left is Example 4, right is Example 5), as the amount of magnesium oxide added increases, the glassy layer on the surface of the purple pottery bowl becomes thicker and the surface glossiness improves.

[0109] Compared with Example 6, more magnesium oxide powder is added in Comparative Example 1. Due to the increase in the amount of addition, the component of purple pottery itself in the mud is less, the physical properties of the purple pottery product are greatly changed, and the surface of the produced purple pottery bowl has more glassy layers. Although the glossiness is more obviously improved, the effect is similar to that of adding glaze, but the texture of the purple pottery itself is lost, and the increase in the amount of addition will also increase the cost.

[0110] Compared with Example 4, Comparative Example 2 added a smaller amount of magnesium oxide powder. Due to the small amount of addition, the effect was not obvious. It was difficult to see the glassy layer on the surface of the purple pottery bowl produced, and the surface glossiness was slightly improved.

[0111] Compared with Example 5, Comparative Example 3 did not add sodium silicate nonahydrate to improve the fluidity of the mud. During the step of pouring out the excess mud, due to the poor fluidity of the mud, the amount of mud remaining in the gypsum mold was large and uneven, the produced purple pottery bowl body was uneven, and the finished product occasionally cracked after firing.

[0112] In Comparative Example 4, compared with Example 5, more sodium silicate nonahydrate was added, and the fluidity of the mud was very strong but the viscosity was poor. The mud needed to be kept in the gypsum mold for a longer time to ensure that it had a thickness sufficient to support the structure of the green body itself. Due to the insufficient viscosity, the influence of gravity was more obvious, and the lower layer of the green body would be thicker than the upper layer of the green body, resulting in uneven overall quality of the green body.

[0113] Compared with Example 5, the added magnesium oxide powder in Comparative Example 5 is coarser, and the particles of magnesium oxide in the purple pottery body are larger, resulting in a higher local magnesium oxide content. The glassy layer on the surface of the fired purple pottery is not uniform, and the transparency of the glassy layer on the surface is insufficient.

[0114] Experimental Example 1

[0115] Oil drop cleaning experiment:

[0116] Traditional purple pottery bowl preparation steps:

[0117] Weigh the Jianshui white mud slurry, filter it through a 200-300 mesh screen, press filter and then knead the mud to make mud material.

[0118] The clay is formed into a bowl shape by wheel throwing, with an outer diameter of 17.5 cm, a height of 5.7 cm and a thickness of 1 cm. After wheel throwing, the clay is trimmed and dried at room temperature for 24 hours.

[0119] After the green body is dried, the temperature is raised to the sintering temperature, kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

[0120] At the same time, edible oil was dripped into the bowl wall of the purple pottery with glossy texture prepared in Experimental Example 1 and the traditional purple pottery prepared in the above steps.

[0121] All were rinsed with deionized water, dried at 60°C, and their cleanliness was observed.

[0122] The bowl wall of Experimental Example 1 is as follows Figure 4 As shown in the figure, there is no obvious oil stain on the surface after drying. The bowl wall of traditional purple pottery is Figure 5 As shown, there are obvious oil marks left on the surface after drying.

[0123] The results in Experimental Example 1 show that the purple pottery product after adding magnesium oxide powder has a certain easy-to-clean effect.

Claims

1. A method for preparing a purple pottery product, the method comprising: 1) Weighing cement slurry, adding 5%-30% of the dry weight of the slurry to the slurry, and refining the slurry to obtain slurry material after drying; 2) kneading the clay material evenly, squeezing out bubbles, and forming the clay material into a green body by wheel throwing, and trimming the green body after it is half dry; 3) drying the green body, raising the temperature to a sintering temperature, maintaining the temperature at the sintering temperature for 20 minutes, and then cooling to room temperature to obtain a purple pottery product.

2. The preparation method according to claim 1, wherein In step 1), the Jianshui mud is made of clay raw materials from Jianshui County, Yunnan Province, including red mud and white mud.

3. The preparation method according to claim 1 or 2, wherein When making mud, use a sieve with a mesh size of 200-300 to filter.

4. The preparation method according to claim 2, wherein In step 3), the sintering temperature of red mud is 1150°C, and the sintering temperature of white mud is 1200°C.

5. A method for preparing a purple pottery product, the method comprising: 1) Weigh cement slurry, add sodium silicate nonahydrate powder accounting for 0.5%-5.0% of the slurry solid content by mass fraction, and micron-grade magnesium oxide powder accounting for 5%-30% of the slurry solid content by mass fraction, and stir to form slurry; 2) Inject the slurry into the plaster mold, keep it for 30-120 seconds, pour out the wet slurry, demould it after drying, and repair the blank; 3) After the green body is dried, the temperature is raised to the sintering temperature, kept at the sintering temperature for 20 minutes, and then cooled to room temperature.

6. The preparation method according to claim 5, wherein: In step 1), the Jianshui mud is made of clay raw materials from Jianshui County, Yunnan Province, including red mud and white mud.

7. The preparation method according to claim 5, wherein: In step 1), the cement slurry is filtered through a sieve with a mesh size of 60 or more; the water content of the cement slurry is 30%-40%.

8. The preparation method according to claim 5, wherein In step 2), the drying time is at least 2 hours.

9. The preparation method according to claim 6, wherein: In step 3), the sintering temperature of red mud is 1150°C, and the sintering temperature of white mud is 1200°C.

10. A purple pottery product obtained by the preparation method according to any one of claims 1 to 9.

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