CN110615666A - Firing process for combination of purple sand and ceramic - Google Patents

Abstract

A firing process for combining purple sand and ceramic comprises the following steps: preparing purple sand pug: selecting a purple sand blank, adding water and stirring uniformly to obtain a purple sand pug; blank forming: producing a first blank of a blank by using purple sand pug; pressing and benefiting: placing the primary blank of the blank in a shade place for natural drying in the shade, lightly pressing the surface of the blank by hands to ensure that the periphery of the blank is regular and uniform, and finally utilizing a cutter to ensure that the surface of the ceramic is smooth and clean to obtain a secondary blank of the blank; washing a blank: continuously placing the blank body second prototype in a shade place for natural shade drying, cleaning the blank body second prototype when the surface of the blank body second prototype begins to harden, and placing the blank body second prototype in the shade place for airing after the cleaning is finished; firing for the first time; the purple sand product can be beautified by firing and combining the purple sand and the ceramic, so that the simplicity, the thickness and the charming are realized.

Description

Firing process for combination of purple sand and ceramic

Technical Field

The invention relates to the technical field of ceramics, in particular to a firing process for combining purple sand and ceramics.

Background

The purple sand is a ceramic product between pottery and porcelain, and is characterized by compact structure, close to porcelain, higher strength, fine particles, shell-shaped or stone-shaped fracture, and small particle-shaped change in the smooth surface of the pottery, thereby showing a sandy effect, but not having the translucency of porcelain body, being widely loved by tea people, but being too simple due to single color and monotony for some people.

Disclosure of Invention

The invention aims to provide a firing process for combining purple sand and ceramics so as to solve the problems in the background technology.

In order to realize the purpose, the firing process for combining the purple sand and the ceramics comprises the following steps:

(1) preparing purple sand pug: selecting a purple sand blank, adding water and stirring uniformly to obtain a purple sand pug;

(2) blank forming: producing a first blank of a blank by using purple sand pug;

(3) pressing and benefiting: placing the primary blank of the blank in a shade place for natural drying in the shade, lightly pressing the surface of the blank by hands to ensure that the periphery of the blank is regular and uniform, and finally utilizing a cutter to ensure that the surface of the ceramic is smooth and clean to obtain a secondary blank of the blank;

(4) washing a blank: continuously placing the blank body second prototype in a shade place for natural shade drying, cleaning the blank body second prototype when the surface of the blank body second prototype begins to harden, washing off dust and impurities on the surface of the blank body to avoid the influence of the impurities on the quality of the ceramic, and placing the blank body in the shade place for drying after the cleaning is finished;

(5) first firing: placing the blank into a kiln for firing at the temperature of 500-700 ℃ for 7-9 hours, waiting for 8-12 hours, naturally cooling the kiln, and opening the kiln to take out the ceramic blank;

(6) polishing: finishing the ceramic blank by using a grinding machine or sand paper;

(7) surface beautification treatment: crackle glaze is coated on the surface of the ceramic blank;

(8) and (3) second firing: and (3) placing the ceramic blank into a kiln for firing at the temperature of 1200-1300 ℃, for 7-9 hours, waiting for 12-18 hours, naturally cooling the kiln, and opening the kiln to take out the ceramic finished product.

Preferably, the purple sand blank is made of Yixing purple sand mud or Jingdezhen purple sand mud, when the purple sand blank is mixed with water, the purple sand blank and the water are mixed according to the mass ratio of 4:1-5:1, the obtained purple sand mud is too dry and is not easy to form when the water is too little, and the prepared blank is too soft and is not easy to shape when the water is too much.

Preferably, the purple sand blank comprises the following components in parts by weight: 55 parts of purple sandy soil, 15 parts of clay, 3 parts of kaolin, 3 parts of alumina, 3 parts of sodium oxide, 3 parts of potassium oxide, 3 parts of water reducing agent, 2 parts of quartz, 2 parts of mica, 7 parts of mullite and 4 parts of dispersing agent, wherein the content (mass fraction) of iron and oxides thereof in the clay is not more than 7%.

Preferably, in the stage of producing the purple sand pug, after the purple sand blank is selected, the iron and the oxides thereof in the purple sand blank can be separated by adopting a magnetic separation method or an ultrasonic method, so that the influence of excessive iron impurities in the purple sand blank on the stability of the product during firing is prevented, specifically, the magnetic separation method is a technology for separating the iron and the oxides thereof from the purple sand blank by utilizing the magnetic difference of minerals and the physical effect that magnetized substances are bound to be acted by magnetic force in a magnetic field, and particularly, the iron minerals in the shape of strong magnetic particles can be removed; the ultrasonic method is that slurry obtained by mixing the purple sand blank and water is placed under the action of ultrasonic waves, so that raw material particles and aqueous solution in the slurry generate high-frequency vibration, and iron minerals in the raw material particles are stripped and removed through mutual collision and friction between the raw material particles and the aqueous solution, so that the aim of removing iron impurities is fulfilled; the two iron removal modes are good, but the application is relatively less in the general ceramic manufacturing process, in the general ceramic production process, in order to prevent the iron content from being too high, a mode of filtering the slurry formed by mixing the purple sand blank with water by using non-woven fabrics is generally adopted, and most of iron minerals and other impurities can be removed by using the mode.

Preferably, the blank forming can be slip casting or stretch forming, the slip casting can be performed in a mold, and the stretch forming can be performed on a steamboat.

Preferably, an alumina block or alumina powder is paved in the kiln, then the ceramic is placed on the alumina, if a plurality of groups of ceramic body prototypes are fired at one time, the distance between the ceramic body prototypes needs to be controlled, the ceramic body prototypes are reasonably placed according to the internal structure of the kiln and the size of the ceramic body prototypes to be fired, and sufficient flame paths are reserved.

Preferably, the glaze is a colorless or colored vitreous thin layer attached to the surface of the ceramic body, and is glaze slip prepared by grinding mineral raw materials, and generally can be divided into transparent glaze, opaque glaze, colored glaze, glazed glaze, dull glaze, crack glaze, crystal glaze and the like, glazing is also called glazing, and the common glazing method comprises the following steps: spraying, blowing, dipping, pouring, swinging and the like.

Preferably, the firing temperature and the firing time required for firing different glazes are slightly different, and a plurality of different glazes need to be fired on the purple sand for multiple times, as a preferred technical scheme, when the crack glaze is fired, the temperature in the kiln furnace is controlled to be 600 ℃ for the first firing, and the firing time is 8 hours; the second firing is carried out by controlling the temperature in the kiln to be 1280 ℃ and the firing time to be 8 hours.

Preferably, the surface beautifying treatment can be selected from an over-glaze decal process, an under-glaze decal process and a manual thread hooking process.

Preferably, the over-glaze applique process comprises the steps of:

(1) crackle glaze is coated on the surface of the ceramic blank;

(2) tearing off the PVB film printed with the pattern on the decal paper on the ceramic glaze;

(3) soaking the decal paper on the ceramic glaze into alcohol and taking out;

(4) pasting decal paper on the ceramic glaze to the corresponding position on the ceramic blank;

and in the process of firing the ceramic body in a kiln, the PVB film on the other side can be carbonized and decomposed, and the patterns on the decal paper are attached to the surface of the ceramic to finish the color arrangement on the ceramic.

Preferably, the underglaze decal process comprises the following steps:

(1) manufacturing a plastic sheet with the same size as the ceramic underglaze decal paper and pasting the plastic sheet to the corresponding position of the ceramic blank;

(2) crackle glaze is coated on the surface of the ceramic blank;

(3) taking down the plastic sheet;

(5) tearing off the PVB film printed with the pattern on the decal paper under the ceramic glaze;

(4) soaking the ceramic underglaze decal paper into alcohol and taking out;

(5) pasting the ceramic underglaze decal paper to the position of the plastic sheet on the ceramic blank;

(6) tearing off lining paper on the decal paper under the ceramic glaze;

(7) and coating a layer of transparent glaze on the vacant area of the plastic sheet.

Preferably, the manual thread hooking process comprises the following steps:

(1) drawing a picture on the ceramic blank by using a painting brush;

(2) performing line drawing according to the drawing marks by using a line drawing pen;

(3) applying transparent glaze on a painting area on the ceramic blank;

(4) and applying crack glaze on the rest part of the ceramic body.

Preferably, for some high-end manually-drawn line vases, after the line drawing is finished, a 'water mixing' process can be carried out continuously, namely, in a drawn contour line, a painting brush is used for sucking the green material mixed water with the water content of 82-96%, color filling is carried out according to the drawn contour line, so that the color on the vase is dark and light, the material water is also dark and light, and the painting on the ceramic through the 'water mixing' process can have the elegant and exquisite levels of the chap method and the dyeing method of the traditional Chinese water-ink mountain water, and the integral quality of the ceramic is greatly improved.

In conclusion, the beneficial effects of the invention are as follows: the process can combine the dark-red enameled pottery with other colorful ceramics, and wraps beautiful ceramics on the outer layer on the basis of not giving up all the advantages of the dark-red enameled pottery, thereby realizing simple and thick appearance and good charm; by improving the firing process, the novel high-quality production with good ceramic combination condition, no cracking of the ceramic body and low overall defective rate is realized; meanwhile, the manufacturing process of combining the purple sand with ceramics in different grades is provided, and the method is suitable for the application of ceramic enterprises and improves the market competitiveness.

Detailed Description

In the following, embodiments of the present invention are described in further detail, it should be noted that the examples are merely illustrative of the present invention and should not be considered as limiting, and that all features disclosed in the examples of the present invention, or steps in all methods or processes disclosed, can be combined in any way, except for mutually exclusive features and/or steps.

Example 1

The embodiment provides a firing process for combining purple sand and ceramic, which comprises the following steps:

(1) preparing purple sand pug: selecting a purple sand blank, adding water and stirring uniformly to obtain a purple sand pug;

(2) blank forming: producing a first blank of a blank by using purple sand pug;

(3) pressing and benefiting: placing the primary blank of the blank in a shade place for natural drying in the shade, lightly pressing the surface of the blank by hands to ensure that the periphery of the blank is regular and uniform, and finally utilizing a cutter to ensure that the surface of the ceramic is smooth and clean to obtain a secondary blank of the blank;

(4) washing a blank: continuously placing the blank body second prototype in a shade place for natural shade drying, cleaning the blank body second prototype when the surface of the blank body second prototype begins to harden, washing off dust and impurities on the surface of the blank body to avoid the influence of the impurities on the quality of the ceramic, and placing the blank body in the shade place for drying after the cleaning is finished;

(5) first firing: placing the blank into a kiln for firing at the temperature of 500-700 ℃ for 7-9 hours, waiting for 8-12 hours, naturally cooling the kiln, and opening the kiln to take out the ceramic blank;

(6) polishing: finishing the ceramic blank by using a grinding machine or sand paper;

(7) surface beautification treatment: and the surface of the ceramic blank is provided with crack glaze.

(8) And (3) second firing: placing the ceramic blank into a kiln for firing at the temperature of 1200-1300 ℃, the firing time of 7-9 hours, waiting for 12-18 hours, naturally cooling the kiln, opening the kiln and taking out the ceramic finished product;

specifically, the shady and cool place refers to a place without direct sunlight and wind, the ambient temperature is 0-20 ℃, and the humidity is 20-40%; naturally drying in the shade refers to a process of placing the blank embryonic form in a shade place and gradually evaporating the water in the blank embryonic form; drying means that the surface of the blank cannot see moisture with naked eyes; the method for distinguishing whether the surface of the second prototype of the blank begins to harden or not comprises the following steps: the surface of the blank is normally pressed by fingers, and a pressing trace cannot be left on the blank for the second time, namely the surface of the blank for the second time is considered to be hardened, and the pressure of the normal pressing of the fingers of an adult is 5-15N.

The purple sand blank is preferably made of Yixing purple sand mud or Jingdezhen purple sand mud, when the purple sand blank is mixed with water, the purple sand blank and the water are mixed according to the mass ratio of 4:1-5:1, the obtained purple sand mud is too dry and not easy to form when the water is too little, and the prepared blank is too soft and not easy to shape for the first time when the water is too much.

Advantageously, the purple sand blank comprises the following components in parts by weight: 55 parts of purple sandy soil, 15 parts of clay, 3 parts of kaolin, 3 parts of alumina, 3 parts of sodium oxide, 3 parts of potassium oxide, 3 parts of water reducing agent, 2 parts of quartz, 2 parts of mica, 7 parts of mullite and 4 parts of dispersing agent, wherein the content (mass fraction) of iron and oxides thereof in the clay is not more than 7%.

Beneficially, in the stage of producing the purple sand pug, after selecting the purple sand blank, the iron and the oxides thereof in the purple sand blank can be separated by adopting a magnetic separation method or an ultrasonic method, so as to prevent the influence of excessive iron impurities in the purple sand blank on the stability of the product during firing, and the influence of the iron content on firing, and specifically, the influence of the iron content in clay on firing of the lightweight/ultralight sludge ceramsite, which is published on line at 11, 23 and 2010 by "Zengyuanyan", is referred to, the influence of the iron content in clay on firing of the lightweight/ultralight sludge ceramsite is referred to, the other basically similar clay has the characteristic of expansibility except for the iron content in clay, the mineral components in the clay are different except for quartz, so that the fired ceramsite has different mineral components, but the mineral components do not influence the expansibility of the ceramsite during firing, and in addition, the higher the iron content in the clay, the better the expansibility of the ceramsite is, resulting in a thinner ceramsite shell with a higher water absorption.

Specifically, the magnetic separation method is a technology for separating iron and oxides thereof from purple sand blanks by utilizing the magnetic difference of minerals and according to the physical effect that magnetized substances are bound to be acted by magnetic force in a magnetic field, and particularly can remove iron minerals in the form of strong magnetic particles; the ultrasonic method is that slurry obtained by mixing the purple sand blank and water is placed under the action of ultrasonic waves, so that raw material particles and aqueous solution in the slurry generate high-frequency vibration, and iron minerals in the raw material particles are stripped and removed through mutual collision and friction between the raw material particles and the aqueous solution, so that the aim of removing iron impurities is fulfilled; the two iron removal modes are good, but the application is relatively less in the general ceramic manufacturing process, in the general ceramic production process, in order to prevent the iron content from being too high, a mode of filtering the slurry formed by mixing the purple sand blank with water by using non-woven fabrics is generally adopted, and most of iron minerals and other impurities can be removed by using the mode.

Advantageously, the blank forming can be slip casting or stretch forming, the slip casting can be completed in a mold, and the stretch forming can be completed on a steamboat.

Beneficially, the kiln needs to be paved with alumina blocks or alumina powder, then the ceramic is placed on the alumina, if a plurality of groups of ceramic body prototypes are fired at one time, the distance between the ceramic body prototypes needs to be controlled, the ceramic body prototypes are reasonably placed according to the internal structure of the kiln and the size of the ceramic body prototypes to be fired, and sufficient flame paths are reserved.

Advantageously, the glaze is a colorless or colored vitreous thin layer attached to the surface of a ceramic body, and is a glaze slip prepared by grinding mineral raw materials, and can be generally divided into transparent glaze, opaque glaze, colored glaze, glazed glaze, dull glaze, crack glaze, crystalline glaze and the like, glazing is also called glazing, and the common glazing method comprises the following steps: spraying, blowing, dipping, pouring, swinging and the like.

Beneficially, the firing temperature and the firing time required for firing different glazes are slightly different, and multiple different glazes need to be fired for multiple times when fired on the purple sand, in the cracked glaze fired in this embodiment, the kiln temperature should be controlled to be 600 ℃ during the first firing, and the firing time should be 8 hours; and controlling the temperature in the kiln to be 1280 ℃ during the second firing, wherein the firing time is 8 hours.

Advantageously, the surface beautification treatment can be selected from an over-glaze decal process, an under-glaze decal process, a manual thread hooking process.

Advantageously, the over-glaze decorating process comprises the following steps:

(1) crackle glaze is coated on the surface of the ceramic blank;

(2) tearing off the PVB film printed with the pattern on the decal paper on the ceramic glaze;

(3) soaking the decal paper on the ceramic glaze into alcohol and taking out;

(4) pasting decal paper on the ceramic glaze to the corresponding position on the ceramic blank;

and in the process of firing the ceramic body in a kiln, the PVB film on the other side can be carbonized and decomposed, and the patterns on the decal paper are attached to the surface of the ceramic to finish the color arrangement on the ceramic.

Advantageously, the underglaze decal process comprises the steps of:

(1) manufacturing a plastic sheet with the same size as the ceramic underglaze decal paper and pasting the plastic sheet to the corresponding position of the ceramic blank;

(2) crackle glaze is coated on the surface of the ceramic blank;

(3) taking down the plastic sheet;

(5) tearing off the PVB film printed with the pattern on the decal paper under the ceramic glaze;

(4) soaking the ceramic underglaze decal paper into alcohol and taking out;

(5) pasting the ceramic underglaze decal paper to the position of the plastic sheet on the ceramic blank;

(6) tearing off lining paper on the decal paper under the ceramic glaze;

(7) and coating a layer of transparent glaze on the vacant area of the plastic sheet.

Advantageously, the manual hooking process comprises the following steps:

(1) drawing a picture on the ceramic blank by using a painting brush;

(2) performing line drawing according to the drawing marks by using a line drawing pen;

(3) applying transparent glaze on a painting area on the ceramic blank;

(4) and applying crack glaze on the rest part of the ceramic body.

Beneficially, for some high-end manually-drawn line vases, after the line drawing is finished, the water mixing process can be carried out continuously, namely, in the drawn contour line, a painting brush is used for sucking the green material mixed water with the water content of 82-96%, color filling is carried out according to the drawn contour line, so that the color on the vase is dark and light, the material and the water are also dark and light, and the drawing on the ceramic through the water mixing process can have the elegant and exquisite levels of the chap method and the dyeing method of the traditional Chinese water-ink mountain water, and the integral quality of the ceramic is greatly improved.

In order to obtain the iron content of the clay suitable for the combination of firing the purple sand and the ceramic, five groups of comparative examples are set.

Respectively taking Hangzhou Dongzhou dock clay, Shandong catabo clay, Henan clay (moisture soil), Guangxi clay (brick red soil) and Guizhou clay (yellow soil), loosening the clay respectively, placing the clay in an electrothermal constant-temperature forced air drying oven at 100 ℃ for continuously drying for 4 hours, sieving the dried clay samples by using an electromagnetic sample-making crusher with 100 meshes (the particle diameter is less than 0.150mm), and respectively taking 700g of the clay samples and storing the clay samples in a polyethylene plastic bottle for sealed storage.

Comparative example 1, clay from Dongzhou dock

200g of clay sample is taken out from Dongkoushan clay sample in Hangzhou, and the mass fraction of iron is measured to be 4.43 percent according to the GB/T16399-1996 national standard of the people's republic of China-clay chemical analysis method.

Then 150g of clay is taken out from the Hangzhou Dongzhou depressed clay sample to prepare the purple sand pug according to the preparation method and the proportion of the purple sand pug in the embodiment 1, in order to save time and accelerate the test progress, finished ceramic is not prepared here, the purple sand pug is put into a ball forming mill (DZ-20 manufactured by Chinese pharmaceutical machinery factory), and is rolled to be ball forming, and is placed in a fume hood for 24 hours and normal temperature drying after being screened by a sieve with 5-6mm of sieve pores, the temperature in the fume hood is controlled to be about 20 ℃, the humidity is 40%, the raw haydite after being dried at normal temperature is placed in a high temperature tubular resistance furnace with 1280 ℃ for firing for 20 minutes, finally, the raw haydite is taken out and is placed in the fume hood for natural cooling to the room temperature, the mass M1 of all the raw haydite at the moment is measured, after the measurement, all the raw haydite is placed in a sieve with 3-4, and fishing out all the raw ceramsite by using a sieve, placing the raw ceramsite in a fume hood for 5 hours until the water stain on the surface is completely evaporated, measuring the mass M2 of the raw ceramsite, and measuring the water absorption of the ceramic ball by using a formula.

Water absorption rate (M2-M1)/M1.

The water absorption was 6.8%.

Comparative example 2 Shandong Zibo clay

200g of the Zibo clay sample is taken out from the Shandong, and the mass fraction of the iron is measured to be 8.47 percent according to the GB/T16399-1996 national standard of the people's republic of China-clay chemical analysis method.

Other embodiments of comparative example 2 were the same as comparative example 1, and water absorption was measured.

The water absorption was 10.2%.

COMPARATIVE EXAMPLE 3 Henan Clay (Chaochloa)

200g of the iron is taken out from the clay sample in Henan, and the mass fraction of the iron is measured to be 5.45 percent according to the GB/T16399-1996 national standard of the people's republic of China-clay chemical analysis method.

Other embodiment of comparative example 3 the water absorption was measured as in comparative example 1.

The water absorption was 7.5%.

COMPARATIVE EXAMPLE 4 Guangxi Clay (Tile red soil)

200g of the iron is taken out from the Guangxi clay sample, and the mass fraction of the iron is 11.61 percent according to the GB/T16399-1996 national standard of the people's republic of China-clay chemical analysis method.

Other embodiment of comparative example 4 was the same as comparative example 1, and water absorption was measured.

The water absorption was 12.4%.

Comparative example 5 Guizhou Clay (yellow loam)

200g of the iron is taken out from a Guizhou clay sample, and the mass fraction of the iron is measured to be 22.31 percent according to the GB/T16399-1996 national standard of the people's republic of China-clay chemical analysis method.

Other embodiment of comparative example 5 was the same as comparative example 1, and water absorption was measured.

The water absorption was 15.1%.

Control group, Jingdezhen top grade red porcelain mud (goods number GZ-TNHt)

The purple sand mud of Jingdezhen top grade is directly available purple sand mud material, and the mass fraction of iron in clay of the purple sand mud is difficult to measure, so that the mass fraction is not measured, and the experimental result is not greatly influenced.

1000g of Jingdezhen purple sand mud is taken, 200g of water is added, the mixture is put into a ball forming mill (DZ-20 manufactured by pharmaceutical machinery factory in China, China and south) to be rolled into balls, sieving the balls by a sieve with 5-6mm meshes, placing the sieved balls in a fume hood for drying at normal temperature for 24 hours, controlling the temperature in the fume hood to be about 20 ℃ and the humidity to be 40%, placing the raw ceramsite dried at normal temperature in a high-temperature tubular resistance furnace at 1280 ℃ for firing for 20 minutes, finally taking out the raw ceramsite and placing the raw ceramsite in the fume hood for natural cooling to room temperature, measuring the mass M1 of all the raw ceramsite at the moment, and after the measurement is finished, using a sieve with 3-4mm sieve pores to hold all the raw haydite, immersing the raw haydite in water for 3 hours, and fishing out all the raw ceramsite by using a sieve, placing the raw ceramsite in a fume hood for 5 hours until the water stain on the surface is completely evaporated, measuring the mass M2 of the raw ceramsite, and measuring the water absorption of the ceramic ball by using a formula.

The water absorption was 9.1%.

All data were collated to give table 1:

table 1 data records and water absorption calculations

Rearrangement according to water absorption gave table 2:

TABLE 2 data after rearrangement according to water absorption

	Mass fraction of iron	M1(g)	M2(g)	Water absorption rate
					Comparative example 1	4.43％	975.1	1041.4	6.8％
Comparative example 3	5.45％	970.2	1043.0	7.5％
					Control group	Not testing	984.2	1073.8	9.1％
Comparative example 2	8.47％	965.0	1063.4	10.2％
					Comparative example 4	11.61％	952.8	1070.9	12.4％
Comparative example 5	22.31％	947.3	1090.3	15.1％

As can be seen from the data in Table 2, the higher the iron content (mass fraction) in the clay, the higher the water absorption of the produced ceramsite is, the higher the water absorption represents that the body of the dark-red enameled pottery produced by the material is loose and the mud door is loose, the general requirement of the industry for high-quality dark-red enameled pottery is that the water absorption of the finished product is lower than 1.5%, the dark-red enameled pottery produced by the sintering process in example 1 is made by using the Jingdezhen top purple clay in the control group, the weight M3 is measured, then the pottery is filled with water, the pottery is poured out after standing for 12 hours, and the residual water stain in the pottery is wiped by using a dry towel, and the weight M4 is measured.

It should be noted that the standard in the industry is finished product water absorption, which is different from the test method of raw ceramsite water absorption measured by the experiment, and therefore the test result is also different.

TABLE 3 Water absorption test of finished purple sand ceramic pots made from purple sand mud, a top grade of Jingdezhen

	M3(g)	M4(g)	Finished product water absorption rate
				Control group	1612.5	1635.6	1.43％

The water absorption of the finished product is 1.43% < 1.5%, and the finished product reaches the high-quality acknowledged by the industry.

With the combination of table 2, purple sand blanks manufactured by using the comparative examples 2 (Shandong Zibo clay), 4 (Guangxi clay (brick laterite)) and 5 (Guizhou clay (yellow loam)) cannot meet the requirements of high-quality purple sand pot blanks.

Next, the iron minerals in comparative examples 2, 4 and 5 were removed by using a magnetic separation method (DCZ-200 electromagnetic dry powder automatic magnetic separator, magnetic treatment capacity 1T was selected).

Comparative example 6 Zibo clay from Shandong-magnetic separation method

Taking out 300g of the Shandong Zibo clay sample, putting the sample into a DCZ-200 electromagnetic dry powder automatic magnetic separator, adjusting the magnetic field intensity to be 1T, carrying out magnetic separation for 10 minutes, taking out to obtain the magnetic-separated Shandong Zibo clay, and measuring the mass fraction of iron to be 4.56% according to a GB/T16399 plus-material 1996 national standard of China's republic of China-clay chemical analysis method.

Taking 150g of clay out of the magnetically-separated Shandong Zibo clay, manufacturing the Zibo clay according to the manufacturing method and proportion of the Zibo clay in example 1, rolling the Zibo clay into balls in a ball forming machine (DZ-20 manufactured by pharmaceutical machinery factory in China south-China), screening the balls by using a sieve with 5-6mm of sieve pores, placing the balls in a ventilation cabinet for drying at normal temperature for 24 hours, controlling the temperature in the ventilation cabinet to be about 20 ℃, controlling the humidity to be 40%, placing the dried raw haydite in a high-temperature tubular resistance furnace at 1280 ℃ for firing for 20 minutes, taking out the raw haydite, placing the raw haydite in the ventilation cabinet for naturally cooling to room temperature, measuring the mass M5 of all the raw haydite, after the measurement, using the sieve with 3-4mm of sieve pores to hold all the raw haydite, immersing the raw haydite in water for 3 hours, taking out all the raw haydite by using the sieve, placing the sieve in the ventilation cabinet for, and after the surface water stain is completely evaporated, measuring the mass M6 of the raw ceramic particles, and measuring the water absorption of the ceramic particles by a formula.

The water absorption was 7.2%.

Comparative example 7 Guangxi Clay (brick red soil) -magnetic separation method

Taking out 300g of Guangxi clay (brick red soil) sample, putting the sample into a DCZ-200 electromagnetic dry powder automatic magnetic separator, adjusting the magnetic field intensity to be 1T, taking out the sample after magnetic separation for 10 minutes to obtain the Guangxi clay after magnetic separation, and measuring the mass fraction of iron to be 6.14% according to a clay chemical analysis method which is a national standard of the national people's republic of China in GB/T16399 plus 1996.

The other embodiments of comparative example 7 are the same as comparative example 6.

The water absorption was 8.5%.

Comparative example 8 Guizhou Clay (yellow loam) -magnetic separation method

300g of a Guizhou clay (yellow loam) sample is taken out and put into a DCZ-200 electromagnetic dry powder automatic magnetic separator, the magnetic field intensity is adjusted to be 1T, the Guizhou clay after magnetic separation is obtained after the magnetic separation is carried out for 10 minutes, and 50g of the Guizhou clay is obtained, and the mass fraction of iron is 13.1% according to a GB/T16399 plus 1996 national standards of the people's republic of China-clay chemical analysis method.

The other embodiments of comparative example 8 are the same as comparative example 6.

The water absorption was 12.8%.

TABLE 4 Water absorption of three stocks before and after magnetic separation for deferrization and in combination with control

	Mass fraction of iron	M5(g)	M6(g)	Water absorption rate
					Comparative example 2	8.47％	965.0	1063.4	10.2％
Comparative example 6	4.56％	972.4	1042.4	7.2％
					Comparative example 4	11.61％	952.8	1070.9	12.4％
Comparative example 7	6.89％	962.8	1044.6	8.5％
					Comparative example 5	22.31％	947.3	1090.3	15.1％
Comparative example 8	14.1％	951.7	1073.5	12.8％
					Control group	Not testing	984.2	1073.8	9.1％

It can be known from the data in table 4 that the iron minerals in the purple sand blank can be greatly reduced by using the magnetic separation method to reduce the water absorption of the purple sand pot manufactured by using the material, the comparative example 6 is the magnetic separated Shandong Zibo clay, the comparative example 7 is the magnetic separated Guangxi clay (brick red clay), and compared with the control group, it can be seen that the water absorption of the purple sand pot manufactured by using the two materials and the sintering process in example 1 is respectively 7.2% and 8.5% which are lower than 9.1% of the control group, so that the purple sand ceramic pot manufactured by using the two materials and the sintering process in example 1 can reach a high-quality grade.

Verification is carried out below, purple clay blanks are manufactured by using the magnetic separated Shandong Zibo clay in the comparative example 6 and the magnetic separated Guangxi clay (brick red clay) in the comparative example 7 according to the sintering process in the example 1, purple clay ceramic kettles with the same style as the purple clay manufactured in the Jingdezhen Shangdi town of Table 3 are manufactured, the weight M7 is measured, then, the teapots are filled with water, the teapots are poured out after standing for 12 hours, residual water stains in the teapots are wiped off by using dry towels, and the weight M8 is measured.

TABLE 5 Water absorption test of finished purple sand ceramic pots prepared in comparative example 6 and comparative example 7

The water absorption of the finished product is lower than 1.5 percent, and the finished product reaches the high-quality acknowledged by the industry.

Referring to table 4, in comparative example 8, the water absorption of the produced raw haydite of guizhou clay (yellow loam) after magnetic separation is 12.8%, although it is reduced compared with that before magnetic separation, because the iron content (mass fraction) is still large, the water absorption is still larger than 9.1% of the control group, which cannot meet the requirement of the clay selected in the formulation of the high-quality purple sand blank of example 1, and if it is necessary to select this clay, a magnetic separator with larger magnetic treatment capacity is required.

In summary, the following conclusions can be drawn: the magnetic separation method can reduce the mass fraction of iron in the purple sand blank, so that some clay which cannot meet the requirement originally meets the clay requirement in the embodiment 1, and a high-quality purple sand ceramic product is manufactured, but because the magnetic separator is higher in price and too high in investment and production cost, and is unacceptable for general ceramic manufacturers, the mass fraction of iron can be seen to be 6.89% (Guangxi clay (brick laterite) after magnetic separation) meets the production requirement by combining the data in tables 1 to 5, and therefore the content (mass fraction) of iron and oxides thereof needs to be controlled to be less than 7% when the clay is selected.

The above description is only an embodiment of the invention, but the scope of the invention is not limited thereto, and any changes or substitutions that are not thought of through the inventive work should be included in the scope of the invention. Therefore, the protection scope of the invention should be subject to the protection scope defined by the claims.

Claims (10)

1. A firing process for combining purple sand and ceramics is characterized by comprising the following steps:

(1) preparing purple sand pug: selecting a purple sand blank, adding water and stirring uniformly to obtain a purple sand pug;

(2) blank forming: producing a first blank of a blank by using purple sand pug;

(3) pressing and benefiting: placing the primary blank of the blank in a shade place for natural drying in the shade, then pressing the surface of the blank by hands to ensure that the periphery of the blank is regular and uniform, and finally utilizing a cutter to ensure that the surface of the ceramic is smooth and clean to obtain a secondary blank of the blank;

(4) washing a blank: continuously placing the blank body second prototype in a shade place for natural shade drying, cleaning the blank body second prototype when the surface of the blank body second prototype begins to harden, and placing the blank body second prototype in the shade place for airing after the cleaning is finished;

(5) first firing: placing the blank into a kiln for firing at the temperature of 500-700 ℃ for 7-9 hours, waiting for 8-12 hours, naturally cooling the kiln, and opening the kiln to take out the ceramic blank;

(6) polishing: finishing the ceramic blank by using a grinding machine or sand paper;

(7) surface beautification treatment: crackle glaze is coated on the surface of the ceramic blank;

(8) and (3) second firing: and (3) placing the ceramic blank into a kiln for firing at the temperature of 1200-1300 ℃, for 7-9 hours, waiting for 12-18 hours, naturally cooling the kiln, and opening the kiln to take out the ceramic finished product.

2. The firing process for combining purple sand with ceramics as claimed in claim 1, wherein the blank of purple sand is preferably Yixing top grade purple sand mud or Jingde top grade purple sand mud, and when the blank of purple sand is mixed with water, the blank of purple sand and water are mixed according to the mass ratio of 4:1-5: 1.

3. The firing process for combining purple sand with ceramics as claimed in claim 1, wherein the weight parts of the purple sand blank are as follows: 55 parts of purple sandy soil, 15 parts of clay, 3 parts of kaolin, 3 parts of alumina, 3 parts of sodium oxide, 3 parts of potassium oxide, 3 parts of water reducing agent, 2 parts of quartz, 2 parts of mica, 7 parts of mullite and 4 parts of dispersing agent, wherein the mass fraction of iron and oxides thereof in the clay is not more than 7%.

4. The process of claim 1, wherein during the stage of producing the purple sand pug, the iron and oxides thereof in the purple sand blank can be separated by magnetic separation or ultrasonic separation after the purple sand blank is selected, thereby preventing the stability of the product during firing from being affected by excessive iron impurities in the purple sand blank.

5. The process of claim 1, wherein the blank forming is performed by slip casting or blank drawing, the slip casting can be performed in a mold, and the blank drawing can be performed on a steamboat.

6. The process of claim 1, wherein the first firing is carried out at 600 ℃ for 8 hours; and controlling the temperature in the kiln to be 1280 ℃ during the second firing, wherein the firing time is 8 hours.

7. The firing process for combining purple sand with ceramic as claimed in claim 1, wherein the surface beautification treatment can be selected from over-glaze decal process, under-glaze decal process, and manual thread-hooking process.

8. The firing process for combining purple sand with ceramics as claimed in claim 7, wherein the over-glaze decoration process comprises the following steps:

(1) crackle glaze is coated on the surface of the ceramic blank;

(2) tearing off the PVB film printed with the pattern on the decal paper on the ceramic glaze;

(3) soaking the decal paper on the ceramic glaze into alcohol and taking out;

(4) and pasting the decal paper on the ceramic glaze to the corresponding position on the ceramic blank.

9. The firing process for combining purple sand with ceramic as claimed in claim 7, wherein the underglaze decal process comprises the following steps:

(1) manufacturing a plastic sheet with the same size as the ceramic underglaze decal paper and pasting the plastic sheet to the corresponding position of the ceramic blank;

(2) crackle glaze is coated on the surface of the ceramic blank;

(3) taking down the plastic sheet;

(5) tearing off the PVB film printed with the pattern on the decal paper under the ceramic glaze;

(4) soaking the ceramic underglaze decal paper into alcohol and taking out;

(5) pasting the ceramic underglaze decal paper to the position of the plastic sheet on the ceramic blank;

(6) tearing off lining paper on the decal paper under the ceramic glaze;

(7) and coating a layer of transparent glaze on the vacant area of the plastic sheet.

10. The firing process for combining purple sand with ceramics as claimed in claim 7, wherein the manual thread-hooking process comprises the following steps:

(1) drawing a picture on the ceramic blank by using a painting brush;

(2) performing line drawing according to the drawing marks by using a line drawing pen;

(3) applying transparent glaze on a painting area on the ceramic blank;

(4) and applying crack glaze on the rest part of the ceramic body.