A method for preparing a modified purple pottery product having a high luster texture

Abstract

The present application relates to a kind of modified purple pottery product with high luster texture preparation method, the method comprises: adding a certain proportion of micron grade magnesium oxide powder to building water pottery clay, while controlling the viscosity and moisture content of pottery clay with water;Forming into any shape by pulling blank;Or adding sodium silicate powder and micron grade magnesium oxide powder to building water purple pottery slurry, while controlling the viscosity and fluidity of pottery clay with water, and forming into any shape by slip casting;After drying, calcining, temperature holding cooling to room temperature, form purple pottery product.The purple pottery product prepared by the present application has a glossy surface, is easy to clean and does not leave dirt, and produces a natural jade texture.Compared with the current traditional purple pottery product, which needs to be polished or glazed to have a glossy surface, the present application reduces processing procedures and thus reduces processing cost and energy consumption.In addition, magnesium is an essential and healthy element for human body, so the present application expands the product form of purple pottery and increases the commercial value of JianShui purple pottery.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ceramics, and particularly relates to a preparation method of modified purple pottery products with high light texture. BACKGROUND

[0002] Jianshui purple pottery is a kind of traditional daily-use ceramic produced in Jianshui County, Yunnan Province, and is currently mainly used as tea sets, decorative ornaments, cooking utensils, etc. The current purple pottery products are mainly black, white and red, and the surface texture of non-bamboo-burned and unpolished purple pottery products is relatively single. The current method for obtaining gloss on the surface of purple pottery products is polishing, and unglazed polishing is one of the characteristics of Jianshui purple pottery. However, the cost and price of polished products are also higher than those of unpolished products. The use scenarios of traditional Jianshui purple pottery are limited due to its shape characteristics and price.

[0003] In the field of building materials, magnesium oxide is generally considered to be able to improve the ceramic texture of tiles. However, due to the finer granularity of Jianshui pottery clay compared to other traditional ceramic clay, the surface ceramic texture formed after adding conventional magnesium oxide powder into the purple pottery is uneven. Moreover, too much addition of magnesium oxide powder will cover the original texture of the purple pottery, and too little addition will result in no obvious high light texture on the surface. SUMMARY

[0004] The inventors use Jianshui clay as raw material and magnesium oxide as additive to prepare modified purple pottery products with high light texture through slip casting or injection molding, thereby completing the present application.

[0005] Therefore, in a first aspect, the present application provides a preparation method of purple pottery products, which comprises:

[0006] 1) weighing Jianshui clay, adding 5-30% of micron-sized magnesium oxide powder to the clay based on the dry weight of the clay, drying, refining and making into clay;

[0007] 2) kneading and extruding the clay to remove bubbles, and slip casting the clay to make a green body, and then trimming the green body after it is semi-dry;

[0008] 3) drying the green body, heating to a sintering temperature, keeping 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 clay is made of pottery clay raw materials within the territory of Jianshui County, Yunnan Province, including red clay and white clay. The red clay is generally prepared from 50% five-color clay, 15% loess, 5% white clay and 10% green clay, and the white clay is generally prepared from 65% white clay and 35% green clay. In a preferred embodiment, a sieve with a mesh size of 200-300 is used for filtering when making the clay.

[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 slurry. When the added amount is less than 5%, the glassy layer on the surface of the purple pottery product is difficult to see, and the surface gloss is limitedly improved. When the added amount is greater than 30%, the components of the purple pottery itself in the mud are relatively less, and the physical properties of the purple pottery product are changed more. The surface of the purple pottery bowl has more glassy layer, although the gloss 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 cost is also increased with the increase of the added amount.

[0011] In some embodiments, in step 2), the green body can be of any shape.

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

[0013] In a second aspect, the present application provides another method for preparing a purple pottery product, which comprises:

[0014] 1) A Jianshui mud slurry is weighed, the water content of the Jianshui mud slurry is controlled at 30%-40%, preferably about 35%, 0.5%-5.0% of sodium silicate nine-water powder and 5%-30% of micron-sized magnesium oxide powder are added to the mud slurry, and the mud slurry is prepared after stirring;

[0015] 2) The mud slurry is poured into a gypsum mold and kept for 30-120 seconds, then the wet mud slurry is poured out, dried and demolded, and the green body is trimmed;

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

[0017] In some embodiments, in step 1), the purple clay slurry needs to be filtered through a sieve with a mesh size of 60 or more, and the slurry has a water content of 30-40% when weighed; the purity of the sodium silicate powder and the magnesium oxide powder should be 98% or more. Further, the dry weight of the sodium silicate powder should account for 0.5-5.0% of the total solid content of the slurry. The addition of sodium silicate is to improve the fluidity of the slurry. When the amount of sodium silicate is too small, the slurry has poor fluidity, and thus, when the excess slurry is poured out, the amount of slurry remaining in the gypsum mold is more and uneven, and the resulting purple clay bowl body is uneven, and the finished product may occasionally be cracked after firing. When the amount of sodium silicate is too large, the slurry has strong fluidity but poor viscosity, and thus, the slurry needs to be kept in the gypsum mold for a longer time to ensure that the thickness of the body itself has sufficient support, and due to the insufficient viscosity, the influence of gravity is more obvious, and the lower layer of the body is thicker than the upper layer, resulting in uneven quality of the body as a whole.

[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. 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 application provides a purple pottery product obtained by the above preparation method, which has a high gloss texture. The "high gloss texture" described herein is relative to a conventional purple pottery product without polishing or other modification treatment.

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

[0022] Technical effects

[0023] The present application uses magnesium oxide as an additive to develop a modified purple pottery product with a high gloss texture. Compared with the two methods currently used to change the surface texture of purple pottery products, i.e., charcoal firing and polishing, the present application has the advantages of simple production method, low cost, high yield, and the purple pottery product produced by the present application can adjust the gloss degree of the surface according to the content of the added magnesium oxide. Moreover, magnesium is a healthy element needed by the human body, which expands the form of the purple pottery product and expands the application market of the purple pottery. Furthermore, compared with charcoal firing and polishing, the present application has less energy consumption, and has important application value for sustainable development.

[0024] The addition of magnesium oxide tends to make the ceramic product exhibit a porcelain-like quality. However, when magnesium oxide powder is directly added to the purple clay material, the mixing is not uniform, resulting in a higher local magnesium oxide content in the purple clay body, and the surface glass layer of the fired purple pottery is not uniform in transparency. The inventors have found that when micron-sized (particle size 1-10 microns) magnesium oxide is added to the purple clay material, the surface of the Jian Shui purple pottery product has a uniform high gloss quality, while the surface gloss of the purple pottery product added with coarse magnesium oxide powder (particle size greater than 100 microns) is not uniform, and does not have a complete high gloss quality. This may be due to the fact that the Jian Shui purple clay has a relatively fine particle size, and therefore, the addition of finer magnesium oxide powder can make it more uniform with the clay.

[0025] In addition, magnesium oxide powder is non-toxic and harmless and will not harm the human body. Its presence in the purple clay material can improve the thermal shock resistance and toughness of the purple pottery product. Jian Shui 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 DRAWINGS

[0026] Figure 1 Photo of the purple pottery bowl body with high gloss quality prepared in Example 1;

[0027] Figure 2 Photo of the purple pottery bowl body with high gloss quality prepared in Example 2;

[0028] Figure 3 Photo of the purple pottery bowl body with high gloss quality prepared in Example 3;

[0029] Figure 4 Photo of the purple pottery bowl body with high gloss quality prepared in Example 2 (left) and Example 3 (right);

[0030] Figure 5 Photo of the purple pottery bowl body with high gloss quality prepared in Example 1 after cleaning and drying after the oil drop experiment in Experimental Example 1;

[0031] Figure 6 Photo of the traditional purple pottery bowl body after cleaning and drying after the oil drop experiment in Experimental Example 1. DETAILED DESCRIPTION

[0032] The following reference to the drawings of the specification introduces a plurality of preferred embodiments of the present application, so that its technical content is more clear and convenient to understand. The present application can be embodied in many different forms of embodiments, and the protection scope of the present application is not limited to the embodiments mentioned in the text.

[0033] The magnesium oxide powder used in Examples 1-8 and Comparative Examples 1-4 below is micron-sized magnesium oxide powder with a particle size of 1-10 microns.

[0034] Example 1

[0035] Step: Take the Jianshui white clay slurry, filter through a 200-300 mesh screen, then add 10% wt. magnesium oxide powder to the slurry, press filter, then refine the clay to make the clay material, and the water content of the clay material after refining is about 25% or so.

[0036] Pull the clay material to form a bowl shape, with an outer diameter of 17.5 cm, a height of 5.7 cm, and a thickness of 1 cm, then trim the piece after pulling, and dry at room temperature for 24 hours.

[0037] After the green body is dried, heat to 1200°C, and after holding at the sintering temperature for 20 minutes, cool to room temperature.

[0038] A photo of the purple pottery product after pulling is shown in Figure 1 .

[0039] Example 2

[0040] Step: Take the Jianshui white clay slurry, filter through a 200-300 mesh screen, then add 5% wt. magnesium oxide powder to the slurry, press filter, then refine the clay to make the clay material, and the water content of the clay material after refining is about 25% or so.

[0041] Pull the clay material to form a bowl shape, with an outer diameter of 17.5 cm, a height of 5.7 cm, and a thickness of 1 cm, then trim the piece after pulling, and dry at room temperature for 24 hours.

[0042] After the green body is dried, heat to 1200°C, and after holding at the sintering temperature for 20 minutes, cool to room temperature.

[0043] Example 3

[0044] Step: Take the Jianshui white clay slurry, filter through a 200-300 mesh screen, then add 30% wt. magnesium oxide powder to the slurry, press filter, then refine the clay to make the clay material, and the water content of the clay material after refining is about 25% or so.

[0045] Pull the clay material to form a bowl shape, with an outer diameter of 17.5 cm, a height of 5.7 cm, and a thickness of 1 cm, then trim the piece after pulling, and dry at room temperature for 24 hours.

[0046] After the green body is dried, heat to 1200°C, and after holding at the sintering temperature for 20 minutes, cool to room temperature.

[0047] Example 4

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

[0049] Add 1.86g (1%wt.) sodium silicate nonahydrate and stir to change the rheology of the slip.

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

[0051] Turn the gypsum mold upside down and pour out the slip that has not dried in the gypsum mold. Then, allow the gypsum mold to stand for five hours, demold, and take out the purple pottery body for trimming.

[0052] After drying the body, heat to the sintering temperature (1200°C), and cool to room temperature after keeping at the sintering temperature for 20 minutes.

[0053] The photo of the purple pottery product formed by slip casting is shown in Figure 2 .

[0054] Example 5

[0055] Step: Control the moisture of the JianShui white slip to about 35%, take 500g of the slip, and add 19.44g (10%wt.) of magnesium oxide powder.

[0056] Add 1.96g (1%wt.) sodium silicate nonahydrate and stir to change the rheology of the slip.

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

[0058] Turn the gypsum mold upside down and pour out the slip that has not dried in the gypsum mold. Then, allow the gypsum mold to stand for five hours, demold, and take out the purple pottery body for trimming.

[0059] After drying the body, heat to 1200°C, and cool to room temperature after keeping at the sintering temperature for 20 minutes.

[0060] The photo of the purple pottery product formed by slip casting is shown in Figure 3 .

[0061] Example 6

[0062] Step: Control the moisture of the JianShui white slip to about 35%, take 500g of the slip, and add 75g (30%wt.) of magnesium oxide powder.

[0063] Add 2.53g (1%wt.) sodium silicate nonahydrate and stir to change the rheology of the slip.

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

[0065] Turn the gypsum mold upside down and pour out the slip that has not dried in the gypsum mold. Then, allow the gypsum mold to stand for five hours, demold, and take out the purple pottery body for trimming.

[0066] After drying the body, the temperature is raised to 1200°C, and after 20 minutes of holding at the sintering temperature, it is cooled to room temperature.

[0067] Example 7

[0068] Step: The Jian Shui white clay slurry is controlled to have a moisture content of about 35%, 500g of the clay slurry is weighed, and 19.44g (10%wt.) of magnesium oxide powder is added.

[0069] 0.98g (0.5%wt.) of sodium silicate nonahydrate is added and stirred to change the rheology of the clay slurry.

[0070] The clay slurry is poured into a gypsum mold, and the clay slurry is kept in the mold for 90 seconds.

[0071] The gypsum mold is turned upside down, the clay slurry in the gypsum mold is poured out, and then the gypsum mold is left to stand for five hours, demolded, and the purple pottery body is taken out for trimming.

[0072] After drying the body, the temperature is raised to 1200°C, and after 20 minutes of holding at the sintering temperature, it is cooled to room temperature.

[0073] Example 8

[0074] Step: The Jian Shui white clay slurry is controlled to have a moisture content of about 35%, 500g of the clay slurry is weighed, and 19.44g (10%wt.) of magnesium oxide powder is added.

[0075] 10.23g (5%wt.) of sodium silicate nonahydrate is added and stirred to change the rheology of the clay slurry.

[0076] The clay slurry is poured into a gypsum mold, and the clay slurry is kept in the mold for 90 seconds.

[0077] The gypsum mold is turned upside down, the clay slurry in the gypsum mold is poured out, and then the gypsum mold is left to stand for five hours, demolded, and the purple pottery body is taken out for trimming.

[0078] After drying the body, the temperature is raised to 1200°C, and after 20 minutes of holding at the sintering temperature, it is cooled to room temperature.

[0079] Comparative Example 1

[0080] Step: The Jian Shui white clay slurry is controlled to have a moisture content of about 35%, 500g of the clay slurry is weighed, and 94.23g (35%wt.) of magnesium oxide powder is added.

[0081] 2.72g (1%wt.) of sodium silicate nonahydrate is added and stirred to change the rheology of the clay slurry.

[0082] The clay slurry is poured into a gypsum mold, and the clay slurry is kept in the mold for 90 seconds.

[0083] The gypsum mould is inverted, the slurry in the gypsum mould is poured out, then the gypsum mould is left to stand for five hours, demoulding, and the purple pottery body is taken out for trimming.

[0084] After the body is dried, the temperature is raised to 1200°C, and after the sintering temperature is maintained for 20 minutes, it is cooled to room temperature.

[0085] Comparative Example 2

[0086] Step: The Jian Shui white slurry is controlled to have a moisture content of about 35%, 500g of the slurry is weighed, and 5.41g (3%wt.) of magnesium oxide powder is added.

[0087] 1.82g (1%wt.) of sodium silicate nonahydrate is added and stirred to change the rheology of the slurry.

[0088] The slurry is poured into a gypsum mould, and the slurry is kept in the mould for 90 seconds.

[0089] The gypsum mould is inverted, the slurry in the gypsum mould is poured out, then the gypsum mould is left to stand for five hours, demoulding, and the purple pottery body is taken out for trimming.

[0090] After the body is dried, the temperature is raised to 1200°C, and after the sintering temperature is maintained for 20 minutes, it is cooled to room temperature.

[0091] Comparative Example 3

[0092] Step: The Jian Shui white slurry is controlled to have a moisture content of about 35%, 500g of the slurry is weighed, and 19.44g (10%wt.) of magnesium oxide powder is added.

[0093] The slurry is poured into a gypsum mould, and the slurry is kept in the mould for 90 seconds.

[0094] The gypsum mould is inverted, the slurry in the gypsum mould is poured out, then the gypsum mould is left to stand for five hours, demoulding, and the purple pottery body is taken out for trimming.

[0095] After the body is dried, the temperature is raised to 1200°C, and after the sintering temperature is maintained for 20 minutes, it is cooled to room temperature.

[0096] Comparative Example 4

[0097] Step: The Jian Shui white slurry is controlled to have a moisture content of about 35%, 500g of the slurry is weighed, and 19.44g (10%wt.) of magnesium oxide powder is added.

[0098] 21.60g (10%wt.) of sodium silicate nonahydrate is added and stirred to change the rheology of the slurry.

[0099] The slurry is poured into a gypsum mould, and the slurry is kept in the mould for 90 seconds.

[0100] Turn the gypsum mold upside down, pour out the slurry in the gypsum mold, then let the gypsum mold stand for five hours, demold, and take out the purple pottery body for trimming.

[0101] After drying the body, heat to 1200°C, keep the sintering temperature for 20 minutes, and then cool to room temperature.

[0102] Comparative Example 5

[0103] Step: Control the water content of the Jian Shui white slurry to about 35%, take 500g of slurry, and add 19.44g (10%wt.) of coarse magnesium oxide powder (average particle size >100 microns).

[0104] Add 1.96g (1%wt.) of sodium silicate nonahydrate and stir to change the rheology of the slurry.

[0105] Pour the slurry into the gypsum mold, and keep the slurry in the mold for 90 seconds.

[0106] Turn the gypsum mold upside down, pour out the slurry in the gypsum mold, then let the gypsum mold stand for five hours, demold, and take out the purple pottery body for trimming.

[0107] After drying the body, heat to 1200°C, keep the sintering temperature for 20 minutes, and then cool to room temperature.

[0108] Comparative Example 4 vs. Example 5 Figure 4 As the amount of magnesium oxide added increases, the glassy layer on the surface of the purple pottery bowl is thicker, and the surface gloss improves.

[0109] Comparative Example 1 vs. Example 6, more magnesium oxide powder is added. Due to the increase in the amount added, there are fewer components of the purple pottery itself in the body, and the physical properties of the purple pottery product change more. The surface of the purple pottery bowl produced has more glassy layers, and although the gloss improves more obviously, the effect is similar to adding glaze, but the texture of the purple pottery itself is lost, and the cost increases as the amount added increases.

[0110] Comparative Example 2 vs. Example 4, less magnesium oxide powder is added. Due to the small amount added, the effect is not obvious, and it is difficult to see the glassy layer on the surface of the purple pottery bowl produced, and the surface gloss improves very little.

[0111] Comparative Example 3 vs. Example 5, no sodium silicate nonahydrate is added to improve the fluidity of the slurry. In the step of pouring out the excess slurry, due to the poor fluidity of the slurry, there is more slurry remaining in the gypsum mold and it is not uniform, and the body of the purple pottery bowl produced is not uniform, and the finished product may occasionally crack after firing.

[0112] Comparative Example 4 added more sodium silicate nonahydrate than Example 5, the slurry had strong fluidity but poor viscosity, the slurry needed to be kept in the gypsum mold for a longer time to ensure that the thickness of the slurry had enough support for the structure of the body itself, and due to the insufficient viscosity, the influence of gravity was more obvious, the lower layer of the body would be thicker than the upper layer of the body, resulting in uneven quality of the body as a whole.

[0113] Comparative Example 5 added coarser magnesium oxide powder than Example 5, the magnesium oxide existed in the purple pottery body in larger particles, resulting in higher local magnesium oxide content, and the surface glassy layer of the fired purple pottery had poor uniformity and insufficient transparency.

[0114] Experimental Example 1

[0115] Oil drop cleaning experiment:

[0116] Traditional purple pottery bowl preparation steps:

[0117] The Jian Shui white slurry was filtered through a 200-300 mesh screen, and the filtered slurry was pressed and filtered to prepare the mud material.

[0118] The mud material was drawn into a bowl shape with an outer diameter of 17.5 cm, a height of 5.7 cm, and a thickness of 1 cm. After drawing, the body was trimmed and dried at room temperature for 24 hours.

[0119] After drying the body, the temperature was raised to the sintering temperature, and after maintaining the sintering temperature for 20 minutes, the temperature was cooled to room temperature.

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

[0121] Both were rinsed with deionized water and dried at 60°C, and the cleanliness was observed

[0122] The bowl wall of Experimental Example 1 was as shown in Figure 4 After drying, there was no obvious oil mark on the surface, and the bowl wall of the traditional purple pottery was as shown in Figure 5 After drying, there was an obvious oil mark on the surface.

[0123] The results in Experimental Example 1 showed that the purple pottery product with added magnesium oxide powder had a certain easy-to-clean effect.

Claims

1. A method for preparing a purple clay product, the method comprising: 1) Weigh out the construction mud slurry, add sodium silicate nonahydrate powder accounting for 1%-5.0% of the slurry solid content by mass, and micron-sized magnesium oxide powder accounting for 5%-30% of the slurry solid content by mass, and stir to make the slurry; the construction mud slurry is Jianshui white mud slurry, the white mud is made of 65% white clay and 35% green clay, and the particle size of the micron-sized magnesium oxide powder is 1-10 microns; 2) Pour the slurry into the plaster mold, hold for 30-120 seconds, then pour out the undried slurry, let it dry, demold, and trim the mold. 3) After the green body is dry, heat it to the sintering temperature, hold it at the sintering temperature for 20 minutes, and then cool it to room temperature.

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

3. The preparation method according to claim 1, wherein, In step 2), the drying time should be at least 2 hours.

4. The preparation method according to claim 1, wherein, In step 3), the sintering temperature of the white clay is 1200℃.

5. The purple clay product obtained by the preparation method according to any one of claims 1-4.

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