CN111559868A

CN111559868A - Red underglaze of marigold and method for manufacturing marigold by adopting red underglaze

Info

Publication number: CN111559868A
Application number: CN202010054959.9A
Authority: CN
Inventors: 冯善鑫
Original assignee: Qilu University of Technology
Current assignee: Qilu University of Technology
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2020-08-21
Anticipated expiration: 2040-01-17
Also published as: CN111559868B

Abstract

The invention discloses a red priming glaze of marigold and a method for manufacturing marigold by adopting the red priming glaze of the marigold, wherein the red priming glaze comprises a glaze A and a glaze B, the glaze B accounts for 10% of the weight of the glaze A, and the glaze A is prepared from the following raw materials: 6-8% of feldspar, 5-6% of kaolin, 5-6% of quartz, 5-6% of chalk, 50-60% of frit and 18% of pigment, wherein the sum of the percentages of the raw materials is 100%. The red ground glaze for the calendula officinalis and the method for manufacturing the calendula officinalis by adopting the red ground glaze for the calendula officinalis have the advantages that the color development strength, the stability, the fluidity and the color development uniformity of the glaze are proper, the veins of leaves are clear, and the colors are bright and glossy; the ground glaze is sintered at high temperature, has no heavy metal toxicity and can reach the food grade standard; the firing condition is stable and reliable, the operability is strong, the yield is high, the limitation that the traditional marigold adopts single black ground coat is broken, and the development space of the marigold is expanded.

Description

Red underglaze of marigold and method for manufacturing marigold by adopting red underglaze

Technical Field

The invention relates to a red ground glaze for marigold and a method for manufacturing marigold by adopting the red ground glaze, belonging to the technical field of ceramic materials.

Background

The leaf marigold is formed by sticking the leaves on the surface of a glazed blank and firing at high temperature, and the leaves and the glaze are subjected to complex crystalline state change at high temperature to generate color, so that the meridians of the leaves are clearly and vividly displayed on the porcelain, and the leaf marigold has extremely high artistic value and economic value.

The coloring effect of the wood leaves on the porcelain has strict requirements on the processes of glazing, firing, duration and the like. Although pot marigold has been fired for over 1200 years, black enamel has been the most representative. For example, application No. 201710201678X discloses a method for preparing and using dark-blue-black woodleaf glaze, which replaces or reduces the suspending effect of ceramic glaze material using natural mineral material as solvent in the traditional process by rice husk ash, but uses the traditional black glaze.

With the development of modern technology, people try to adopt glazes of other colors to manufacture the marigold, but complex components in the colored glazes have large influence on vein display effect, and the factors such as the color development strength and uniformity of the glazes, the stability and the fluidity of the glazes need to be considered when the vein grains of the wooden leaves are required to be clearly displayed. For example, if the glaze is too fluid, the marks from the complete blade can be destroyed. The applicant of the invention carries out a large number of experiments by adopting the color glaze materials on the market, and finds that the veins of the marigold leaves obtained by firing the common color glaze materials are unclear or even can not present the veins.

Moreover, the colorful glaze contains a large amount of heavy metals, and cannot reach the food grade standard. For example, the patent application with the application number of 2013101794973 discloses a preparation method of a colorful mother liquid temmoku porcelain and a product prepared by the preparation method, breaks through the bottleneck that only yellowish red leaf veins, black ground glaze and gray brown embryo wood leaf temmoku porcelain can be prepared at that time, and provides a method for preparing the colorful mother liquid temmoku porcelain by using natural minerals and chemical raw materials.

The above description is included in the technical recognition scope of the inventors, and does not necessarily constitute the prior art.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides the red ground glaze of the marigold and the method for manufacturing the marigold by adopting the red ground glaze of the marigold, so that the color selectivity of the red ground glaze of the marigold is more diversified, the limitation that the traditional marigold adopts single black ground glaze is broken, the forms of the marigold are enriched, and the aesthetic value and the aesthetic space of the marigold are improved.

The invention adopts the following technical scheme to realize the purpose:

in one aspect, the application provides a marigold red base glaze, which comprises a glaze A and a glaze B, wherein the glaze B accounts for 10% of the weight of the glaze A, and the glaze A is prepared from the following raw materials in percentage by weight: 6-8% of feldspar, 5-6% of kaolin, 5-6% of quartz, 5-6% of chalk, 50-60% of frit and 18% of pigment, wherein the sum of the percentages of the raw materials is 100%, and the glaze A is recorded;

the glaze B is ferric chloride;

the frit is prepared from the following raw materials in percentage by weight: 20-25% of red lead, 25-35% of quartz, 10-15% of borax, 5-10% of feldspar, 10-15% of limestone and 5-10% of kaolin.

Further, the pigment is prepared from the following raw materials in percentage by weight: 40-50% of tin oxide, 15-25% of quartz, 25-30% of chalk, 3-5% of red lead and 1-5% of potassium dichromate.

Further, the pigment is prepared from the following raw materials in percentage by weight: 63% of red lead, 12% of kaolin, 8% of quartz and Na₂U₂O₇The content was 17%.

Further, the preparation method of the pigment comprises the following steps: the pigment is prepared by uniformly mixing the raw materials for preparing the pigment, calcining, washing and crushing, wherein the calcining temperature is not lower than the high-temperature sintering temperature of the ground glaze, the calcining time is 1-2h, and the crushed ground raw materials are screened by a 300-mesh screen.

Further, the preparation method of the frit comprises the following steps: the frit is prepared by mixing and grinding the raw materials for preparing the frit uniformly, heating at 700-890 ℃ for 1-2h for high-temperature melting, and then quenching rapidly.

Further, the preparation method of the marigold red ground coat comprises the following steps: and (3) putting the glaze A, the glaze B and water into a ball mill according to the specific gravity of 1:0.6-0.8, and carrying out ball milling for 20-80 min.

In another aspect, the application also provides a method for making marigold based on the red glaze base of the marigold, which comprises the following steps: after the green body is formed, carrying out low-temperature biscuit firing, applying base coat, decorating wood leaves and high-temperature firing;

the temperature of the low-temperature biscuiting is 850 ℃, and the temperature of the high-temperature sintering is 1230-1250 ℃.

Further, the green body is made of southern mud or northern mud with low iron content.

Further, the glazing thickness of the ground coat is 1-1.5 mm.

Further, the high-temperature firing is carried out by adopting an air kiln or an electric kiln;

wherein, the high-temperature firing process in the gas kiln comprises the following steps:

heating to 300 ℃ from room temperature at a heating rate of 3-6 ℃/min; heating from 300 ℃ to 500 ℃ at a heating rate of 4-5 ℃/min; heating to 1020 ℃ at the heating rate of 4-5 ℃/min, and keeping the temperature for 30 min; heating to 1230-1250 ℃ at the heating rate of 1-2 ℃/min; then naturally cooling to room temperature;

the high-temperature firing process in the electric kiln comprises the following steps: starting from room temperature, keeping the temperature for 30min at the temperature rise rate of 2-3 ℃/min every time when the temperature rises to 200 ℃ and 1250 ℃, keeping the temperature for 30min after the temperature rises to 1230-1250 ℃, and then naturally cooling to the room temperature.

Further, the wood leaves are dried and shaped before decoration, and the wood leaves are selected from mulberry leaves, broussonetia papyrifera, linden leaves, acer mono, acer truncatum, sweet maples, ficus microcarpa, pomelo leaves, juniper, walnut leaves, adiantum capillus, rubus palmatus leaves, beech leaves, elm leaves, broussonetia papyrifera, hops, fig leaves, poplar leaves, ginkgo leaves, bauhinia, plumeria rubra, luncheon leaves, crambe fruits or banyan fig.

The red ground glaze for the marigold and the method for manufacturing the marigold by adopting the red ground glaze for the marigold provided by the invention have the beneficial effects that but not limited to: (1) the color development strength, stability, fluidity and color development uniformity of the glaze are proper, the veins of the leaves are clear, and the color is bright and glossy; (2) the ground glaze is sintered at high temperature, has no heavy metal toxicity and can reach the food grade standard; (3) the firing condition is stable and reliable, the operability is strong, and the development space of the marigold is expanded. In conclusion, the red ground glaze for the calendula officinalis and the method for manufacturing the calendula officinalis by adopting the red ground glaze for the calendula officinalis, which are provided by the invention, enable the color selectivity of the calendula officinalis ground glaze to be more diversified, break through the limitation that the traditional calendula officinalis adopts single black ground glaze, enrich the forms of the calendula officinalis, and improve the aesthetic value and the aesthetic space of the calendula officinalis.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic view of a kiln firing temperature curve in example 1 of the present application;

FIG. 2 shows the yield at different firing temperatures.

Detailed Description

In order to more clearly explain the overall concept of the present application, the following detailed description is given by way of example. It should be noted, however, that the following detailed description merely gives specific operation examples of the present invention by way of example, and the scope of the present invention is not limited thereto. The scope of the invention is limited only by the claims. It will be obvious to those skilled in the art that various other modifications and substitutions can be made to the described embodiments of the invention within the scope of the invention as defined by the claims and still achieve the same technical result and achieve the final technical object of the invention.

In the present application, all proportions are by weight, temperature is in units of C and pressure is in units of Pa. Room temperature refers to the normal ambient temperature in a laboratory, varying with season and location, and is typically 25 ℃. In addition, all numerical ranges recited herein are inclusive of the endpoints and may include new numerical ranges that combine any of the upper and lower limits of the disclosed ranges with one another. For example, if a component is disclosed as 10 to 30 weight percent, preferably 15 to 25 weight percent, and more preferably 20 to 23 weight percent, then the following numerical ranges are disclosed together: 10-15%, 10-25%, 10-20%, 10-23%, 15-30%, 15-20%, 15-23%, 20-25%, 23-25%.

The method of manufacturing marigold will be described below in examples 1 to 4, and each of the raw materials in examples 1 to 3 is commercially available unless otherwise specified. The weight ratios of the raw materials in examples 1 to 4 are shown in Table 1 below.

Table 1 parts by weight (1 kg per part by weight) of each raw material for preparing marigold red base coat in examples 1 to 3

Example 1:

the red underglaze of marigold and the method for preparing marigold provided by the embodiment adopt the raw materials and the mixture ratio of the embodiment 1 in the table 1, and the specific preparation steps are as follows:

(1) obtaining a blank body: selecting high white porcelain clay with low iron content, preparing a blank with the thickness of 2-3mm by adopting a conventional blank forming and trimming method of daily ceramics, and storing the prepared blank in a shade place for natural drying to ensure that the water content of the blank reaches 1-2%;

(2) low-temperature biscuiting: adopting a kiln for producing domestic ceramics to carry out low-temperature biscuiting on the naturally dried green body, wherein the temperature of the low-temperature biscuiting is 850 ℃, and preparing a biscuiting green body; the specific firing method of the low-temperature bisque firing comprises the following steps: heating from room temperature to 850 deg.C at a heating rate of 2-3 deg.C/min, and maintaining for 30 min;

(3) preparing base glaze slip:

(3-1) preparation of a colorant: according to the proportion in the table 1, the raw materials for preparing the pigment are screened by a 60-mesh screen, are uniformly mixed and then are calcined at 1240 ℃ for 1-2h to stabilize the pigment, then are washed by water to remove soluble substances, and finally are crushed and screened by a 300-mesh screen to prepare the pigment;

(3-2) preparation of frit: mixing the raw materials for preparing the frit according to the proportion in the table 1, grinding uniformly, heating at 780 ℃ for 1-2h, melting at high temperature, and rapidly quenching to obtain the frit;

(3-3) preparing glaze slip: according to the proportion of example 1 in table 1, the raw materials and water are mixed according to the proportion of 1: 0.7, placing the mixture into a ball mill for ball milling, wherein the volume of the milling balls cannot exceed one half of the volume of a milling tank, the ball milling time is about 30min, the rotating speed of the ball mill is 90r/min, and the ball milling particles can pass through a screen with 120 meshes to obtain glaze slurry;

(4) glazing: uniformly spraying the base glaze slip on the surface of the blank body, wherein the thickness of the base glaze slip is about 1.5 mm;

(5) decorating wood leaves: drying and shaping mulberry leaves, placing the mulberry leaves on the surface of a glazed blank, storing the blank in a dry place for natural drying, wherein the specific drying time is determined according to the weather conditions, and is 6-12 hours in rainy days and 2-3 hours in sunny days;

(6) firing in a gas kiln, wherein the atmosphere inside the kiln is a reducing atmosphere, placing the dried glazed green body in a sagger, and placing the sagger in the middle layer of the gas kiln, wherein the specific operation steps are as follows:

a. preheating a gasification furnace in advance;

b. and (3) free water draining stage: opening the gate plate, firing, and completely opening the valve of the gas tank; a proper amount of pressure ignition guns are supplied, the pressure in the kiln is 0.05Pa, and two fire guns are symmetrically ignited; when the gun is ignited, the air valve is closed, and the air valve is adjusted after ignition; the air valve is controlled to adjust blue bottom-supported flame, and the flame is in a jumping shape instead of a straight-line rising type; after the flame is adjusted, the pressure in the kiln is adjusted to 0.005-0.008Pa, the pressure can be different when the volume of the kiln is different, and the pressure needs to be properly controlled according to the volume of each kiln; the temperature is controlled to be increased by 3-6 ℃ within 1 min; adding 2 guns when the temperature is raised to 200 ℃, and pressurizing before adding the guns; adding 2 guns at about 400 deg.C, maintaining for 1min, and increasing temperature by 4-5 deg.C;

c. and (4) structural water draining stage: determining whether the free water is completely discharged or not according to the humidity of the fire observation hole, wherein the free water is completely discharged at about 550 ℃, then closing the door and pressurizing to 0.05Pa, adding a gun, and adjusting the blue flame by opening an air brake;

d. and (3) a heat preservation stage: after the 102-temperature cone is poured, entering a heat preservation stage, closing the adjusting gate, reducing pressure to keep the temperature rise rate at 1 ℃ every 5-6 minutes, and preserving heat for 30-40min to ensure that the atmosphere in the kiln is uniform;

e. a temperature rising stage: closing the gate completely, and pressurizing to above 0.07 Pa; adjusting blue bottom-supported flame through an air valve, and keeping the temperature rise of 2 ℃ every 1 minute; tempering easily occurs at this stage, and the problem that the firing effect is influenced otherwise needs to be solved within 1 min;

f. when the temperature is about 1100 ℃, whether the temperature can be stably raised or not is noticed, and if the temperature is still slowly raised after pressurization, a little gate needs to be opened; when the temperature is about 1200 ℃, attention is paid to observe a No. 6 warm cone, when the warm cone begins to fall down (about 1240 ℃), the fire can be stopped, the cone is gradually fallen down, when the cone is completely fallen down, the cone is 1250 ℃, the firing is stopped when the temperature is controlled to be about 1240 ℃, and a gas tank valve is closed;

g. naturally cooling to room temperature.

In the firing process, whether the pressure in the kiln is normal or not needs to be noticed, when the pressure in the kiln is before closing the kiln door (about 500 ℃), the pressure in the kiln is micro negative pressure under normal conditions, the pressure in the kiln is also micro negative pressure before closing the kiln door to 1020 ℃ (the flame can move towards the inside of the kiln after the fire gun is used for observing the fire, the pressure in the kiln is flat pressure in the heat preservation stage (after 102 is turned over to be strongly reduced), the pressure in the kiln is positive after strongly reducing to be strongly reduced, and the flame is sprayed out from the fire observation hole. Wherein, the positive pressure, the flat pressure and the negative pressure refer to the pressure in the kiln.

Example 2:

the red underglaze of marigold and the method for preparing marigold provided by the embodiment adopt the raw materials and the mixture ratio of the embodiment 2 in the table 1, and the specific preparation steps are as follows:

(1) obtaining a blank body: selecting high white porcelain clay with low iron content, preparing a green body with the thickness of 2-3mm by adopting a conventional green body forming and trimming method of domestic ceramics, and storing the prepared green body in a shade place for natural drying to ensure that the water content of the green body reaches 1-2%;

(3) preparing base glaze slip:

(3-2) preparation of frit: mixing the raw materials for preparing the frit according to the proportion in the table 1, grinding uniformly, heating at 850 ℃ for 1-2h, melting at high temperature, and rapidly quenching to obtain the frit;

(3-3) preparing glaze slip: according to the proportion in the table 1, the raw materials and water are mixed according to the proportion of 1:0.6, placing the mixture into a ball mill for ball milling, wherein the volume of the milling balls cannot exceed one half of the volume of a milling tank, the ball milling time is about 70min, the rotating speed of the ball mill is 90r/min, and the ball milling particles can pass through a screen with 120 meshes to obtain glaze slurry;

(4) glazing: uniformly spraying the ground glaze slip on the surface of the blank body to a thickness of about 1.5 mm;

(5) decorating wood leaves: drying and shaping the bodhi leaves, then placing the bodhi leaves on the surface of a glazed green body, storing the green body in a dry place for natural drying, wherein the specific drying time is determined according to the weather conditions, and is 6-12 hours in rainy days and 2-3 hours in sunny days;

(6) firing in an electric kiln, wherein the kiln atmosphere is an oxidizing atmosphere, placing the dried glazed green body in a sagger, placing the sagger in the middle layer of the electric kiln, and making an electric kiln temperature rise curve at 1240 ℃, wherein the specific temperature rise curve is shown in figure 1.

Example 3:

the red underglaze for marigold and the method for manufacturing marigold provided by the embodiment adopt the raw materials and the mixture ratio in the embodiment 3 in the table 1, and the specific manufacturing method is different from the embodiment 2 in that:

in the step (6), during high-temperature sintering, starting from room temperature, keeping the temperature for 30min at the heating rate of 3 ℃/min at 200 ℃ every time, keeping the temperature for 30min after the temperature is raised to 1230 ℃, and then naturally cooling to the room temperature.

Example 4:

the red underglaze of marigold and the method for manufacturing marigold provided by the embodiment are as follows: 8 parts of feldspar, 5.3 parts of kaolin, 5.5 parts of quartz, 5 parts of chalk, 13.4 parts of minium, 20.4 parts of quartz, 6.4 parts of borax, 4.1 parts of feldspar, 8.7 parts of limestone, 5.2 parts of kaolin, 11.3 parts of minium, 2.2 parts of kaolin, 1.4 parts of quartz, Na₂U₂O₇3.1 parts by weight, 10 parts by weight of ferric chloride, 1kg per part by weight.

The difference between the manufacturing method of the marigold and the embodiment 2 is that:

in the step (6), during high-temperature sintering, the temperature is raised from room temperature at a rate of 3 ℃/min, the temperature is kept for 30min at each temperature rise of 200 ℃, the temperature is kept for 30min after being raised to 1250 ℃, and then the material is naturally cooled to the room temperature.

In the step (4) of the above examples 1 to 4, the glazing process is not limited to the glaze spraying process, but a glaze dipping process may be adopted, but the glaze slip needs to be diluted once, is too thick and is easy to shrink, and the glaze layer needs to be dehydrated by drying in the air or by baking after the glaze dipping process.

The traditional black glaze marigold is not influenced, but the application of the invention uses red glaze, the red color is lighter than the black color, the coverage is poorer, the green body has high iron content and the color is darker, and the color development effect of the red glaze is influenced, the green bodies of the above examples 1 to 4 are made of pug with low iron content, particularly, the pug of porcelain clay, and the fired red glaze has the effect of bright color development.

The evaluation criteria of firing success of the marigold are as follows: the leaves have clear veins, the leaves have no large-scale curling phenomenon, the glaze color is bright, the phenomena of glaze shrinkage, glaze jump and the like do not exist, and the blank is intact. In order to further verify the reliability of the red ground glaze for the marigold and the method for manufacturing the marigold by adopting the red ground glaze for the marigold, the inventor of the application carries out the following comparative tests.

Comparative example 1:

the comparative example is different from example 1 in that in step (3-2), the ball milling time was set to 100min, 110min, and 120min, respectively.

In the process of preparing the marigold according to the comparative example, the ground glaze is easy to crack after being applied to the surface of the blank body and dried, the conditions of glaze shrinkage, glaze jumping and the like are easy to generate during firing, and the prepared marigold ground glaze is uneven in color and dark and light in color.

Comparative example 2:

the difference between this comparative example and example 2 is that in step (6), the temperature was maintained at 200 ℃ for 30min at a rate of 5 ℃/min from room temperature during the high-temperature firing, and after the temperature was raised to 1240 ℃, the temperature was maintained for 30min, and then the material was naturally cooled to room temperature. As a result, it was found that the temperature was increased too rapidly without changing the final firing temperature, and the blade curling phenomenon was severe.

Comparative example 3:

the difference between the comparative example and the example 2 is that in the step (6), when the high-temperature firing is carried out, the temperature is kept for 30min at the temperature rise rate of 1 ℃/min every time when the temperature is raised to 200 ℃, and after the temperature is raised to 1200 ℃, the temperature is kept for 30min, and then the material is naturally cooled to the room temperature. The result shows that the temperature rise is too slow, the fusion degree of the glaze and the blade is large, and the blade is seriously eaten by the glaze.

Comparative example 4:

the comparative example differs from example 1 in that no ferric chloride was added to the ground glaze formulation, and as a result, it was found that the fired muggy glaze had a low color development intensity, a red color as pale red, and a whitish color, and that few products capable of exhibiting veins were obtained, with unclear veins.

In order to verify the stability of the preparation method of calendula officinalis of the present invention, the present inventors conducted the following experiments.

1. Stability test

Three test pieces A, B, C were prepared by the method of steps (1) to (3) in example 1, and the ground coat provided in example 1 was sprayed on the surface.

Three groups of test pieces A, B, C are respectively placed at different directions of the upper layer, the middle layer and the lower layer of the kiln so as to observe whether the color development of the ground glaze has stability and the position with the best sintering effect; the thickness of the base coat on each test piece is divided into a thin thickness and a thick thickness; in order to conveniently observe the color development and the flowability of the glaze materials with different thicknesses, only the upper half part of the test piece is glazed; and (4) engraving scores with different depths on each test piece by using a tool so as to observe the glazing effect with different degrees of layers.

Tests show that (1) the upper layer temperature of the kiln is high, the optimum firing temperature is easily exceeded, and the veins are easily not fired; the middle layer temperature of the kiln is moderate, the kiln position is the best, and the yield is higher than that of other positions; the temperature of the lower layer of the kiln is low, the burnt blades are not melted and are not combined with the blank, and the veins have a high probability of not forming a glass phase.

(2) When the thickness of the ground coat is too thin, the fired cup with the wood leaf has a too light glaze color and unobvious leaf veins, and when the thickness of the ground coat is too thick, the leaf is easy to eat away by the ground coat.

(3) The temperature of the upper layer of the kiln is high, the flowability of the glaze is stronger, and the color development is normal; the color development and the flowability of the middle layer of the kiln are normal; the temperature of the lower layer of the kiln is lower, the glaze is easy to dim and dull, the melting temperature is not reached, and the glaze is not dissolved and is not easy to flow.

2. Effect of temperature on yield

A kiln: an electric or gas kiln;

test piece: repeating the five groups of test pieces a, b, c, d and e for 3 times, wherein each group comprises 20 test pieces;

firing temperature: 1180 ℃, 1200 ℃, 1220 ℃, 1230 ℃, 1240 ℃, 1250 ℃, 1260 ℃, 1280 ℃ and 1300 ℃;

the same procedure and parameters were used for the test pieces of groups a, b and c and example 1 and for the test pieces of groups d and e, respectively, except for the above final firing temperatures, and the average yield at different firing temperatures was shown in FIG. 2. As can be seen from FIG. 2, the temperature range of 1230-1250 ℃ is the optimum temperature, below or above which the end product is not easily burned out, so controlling the kiln temperature is important.

3. Security performance detection

In order to compare the safety performance of the high-temperature glaze provided by the present application with that of a common low-temperature glaze, the following test was performed.

Sample preparation: 200g of common low-temperature red glaze and 200g of marigold red base glaze prepared in the step (3) of the embodiment 1 of the invention;

firing temperature: set at 850 ℃ and 1240 ℃ respectively;

samples a1 (common low-temperature red glaze before lead precipitation), a2 (common low-temperature red glaze after lead precipitation), b1 (calendula red ground coat prepared in step (3) of example 1 of the present invention before lead precipitation), and b2 (calendula red ground coat prepared in step (3) of example 1 of the present invention after lead precipitation);

equipment: ball mills, scanning electron microscopes (product of philips, netherlands), energy spectrometers (product of idax, usa);

accelerating the lead precipitation and placing environment: the temperature was 80 ℃ and the relative humidity was 70%.

The results of the lead precipitation measurement are shown in tables 2 and 3 below.

TABLE 2 common low-temperature red glaze lead precipitation

Name (R)	Pb
		a1	67.6
a2	73.1

TABLE 3 red underglaze lead amount of marigold prepared in step (3) of example 1 of the present application

Name (R)	Pb
		b1
	0
		b2	0

The test shows that the sample a1 before lead precipitation contains high lead, and the lead content of the sample a2 after treatment is higher.

The red priming glaze of calendula officinalis prepared by the invention has no lead element after being fired at high temperature, does not harm the health of users, is safe and nontoxic, obtains new breakthrough in the aspects of edible safety and decorative effect, and has wide application range.

4. Leaf texture sharpness detection

A kiln: an electric or gas kiln;

and (3) kiln temperature: 1240 ℃ of the reaction;

test piece: three groups of 20 pieces each;

numbering: three groups of samples are respectively sprayed with common red glaze beta, traditional marigold black glaze h and red ground glaze M in the embodiment 1 of the invention;

the clarity of the texture of the fired calendula leaves for each set of samples is compared in table 4 below.

TABLE 4 comparison of texture definition of calendula officinalis leaves fired with different glazes

Name (R)	Leaf grain definition
		β	The glaze has light color and unobvious leaf texture
h	The texture is more clear than β, but the yield is low
		M	Clear texture and high yield

Therefore, the glaze has stronger coloring effect than common red glaze, the leaf clearness is clearer than that of the common red glaze and the traditional marigold, and the firing yield is higher than that of the traditional marigold and the common red glaze.

The above-described embodiments should not be construed as limiting the scope of the invention, and any alternative modifications or alterations to the embodiments of the present invention will be apparent to those skilled in the art.

The present invention is not described in detail, but is known to those skilled in the art.

Claims

1. The red priming glaze of the marigold is characterized by comprising a glaze A and a glaze B, wherein the glaze B accounts for 10% of the weight of the glaze A, and the glaze A is prepared from the following raw materials in percentage by weight: 6-8% of feldspar, 5-6% of kaolin, 5-6% of quartz, 5-6% of chalk, 50-60% of frit and 18% of pigment, wherein the sum of the percentages of the raw materials is 100%;

wherein the glaze B is ferric chloride;

2. The calendula officinalis red base glaze according to claim 1, wherein the pigment is prepared from the following raw materials in percentage by weight: 40-50% of tin oxide, 15-25% of quartz, 25-30% of chalk, 3-5% of red lead and 1-5% of potassium dichromate.

3. The calendula officinalis red base glaze according to claim 1, wherein the pigment is prepared from the following raw materials in percentage by weight: 63% of red lead, 12% of kaolin, 8% of quartz and Na₂U₂O₇The content was 17%.

4. The marigold red ground coat according to claim 1, wherein the pigment is prepared by: the pigment is prepared by uniformly mixing the raw materials for preparing the pigment, calcining, washing and crushing, wherein the calcining temperature is not lower than the high-temperature sintering temperature of the ground glaze, the calcining time is 1-2h, and the crushed ground raw materials are screened by a 300-mesh screen.

5. The calendula red base glaze according to claim 1, wherein the frit is prepared by a method comprising: the frit is prepared by mixing and grinding the raw materials for preparing the frit uniformly, heating at 700-890 ℃ for 1-2h for high-temperature melting, and then quenching rapidly.

6. The marigold red ground coat according to claim 1, wherein the marigold red ground coat is prepared by the following steps: and (3) putting the glaze A, the glaze B and water into a ball mill according to the specific gravity of 1:0.6-0.8, and carrying out ball milling for 20-80 min.

7. A method for making marigold, characterized in that the ground coat based on any one of claims 1 to 6 comprises: after the green body is formed, carrying out low-temperature biscuit firing, applying base coat, decorating wood leaves and high-temperature firing;

8. A method of making marigold according to claim 7, wherein the green body is made from southern or northern pug having low iron content.

9. The method of claim 7, wherein the high temperature firing is performed in a gas kiln or an electric kiln;

10. A method of preparing marigold according to claim 7, wherein the leaf is dried and set prior to decorating and is selected from mulberry leaf, larch leaf, linden leaf, maple, ficus auriculata, teak leaf, juniper, walnut leaf, adiantum capillus, raspberry leaf, beech leaf, elm leaf, paper mulberry, hops, fig leaf, poplar leaf, ginkgo leaf, bauhinia, frangipani, donia oblonga leaf, mango fruit or ficus microcarpa.