Lead-free colored crystal glaze and preparation method thereof

Abstract

The lead-free colored crystal glaze is prepared from the following raw materials in parts by weight: 40 to 48 parts of SiO2, 11 to 13 parts of Al2O3, 3.8 to 4.6 parts of K2O, 1.3 to 1.6 parts of Na2O, 0 to 1.5 parts of CaO, 0 to 1.9 parts of BaO, 0 to 1.5 parts of ZnO, 20 to 1.5 parts of TiO2, 0 to 1 part of CoO, 30 to 2 parts of Fe2O3, 8 to 12 parts of MnO, 1 to 30 parts of Bi2O3 and 0.5 to 2 parts of V2O5. A crystallization system composed of bismuth, vanadium and manganese is used for replacing a traditional crystallization system mainly comprising lead, growth of glaze layer crystals is jointly promoted through coordination and cooperation of other components, under the lead-free condition, the safety of the daily porcelain is guaranteed, crystals of different types and different contents are formed, the effect of colored crystallization of the glaze surface of the daily porcelain is achieved, and the service life of the daily porcelain is prolonged. And the glaze surface has the glaze surface texture with multiple changes such as golden color, purple color, green color and blue color, the variability and the metal feeling of the glaze surface are highlighted, the harm to operators in the processing process is reduced, and the health of users is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic materials, and particularly relates to a lead-free colored crystalline glaze and a preparation method thereof. Background Art

[0002] Colored crystalline glaze is a crystalline glaze with a colored metallic texture on the glaze surface, which is widely used in building ceramic tiles and other industries. The typical feature of this type of glaze is that the formula contains a high content of lead oxide, which enables it to adapt to the rapid firing process within 2 hours, and the fired glaze surface presents a golden texture and effect. For example, the Chinese patent application number CN201510230700.4 discloses a glaze for fast-fired crystalline glaze ceramic tiles and a preparation method and application of ceramic tiles. The glaze includes a basic crystalline glaze and a colorant. The basic crystalline glaze includes the following raw materials: zinc oxide, titanium dioxide, quartz, cryolite, zinc phosphate, kaolin, and lead frit. The invention solves the technical problems of complex crystalline glaze firing process, difficult to control crystal flowers, and high production costs, and obtains crystalline glaze art ceramic tiles with good crystallization effect, strong three-dimensional sense and artistic effect. This glaze color is widely used in building ceramics, but due to the quality requirements of lead and cadmium, daily-use porcelain does not meet the health and safety requirements of daily-use porcelain. Therefore, there is an urgent need to develop a colored crystalline glaze suitable for use in the daily-use porcelain industry. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a lead-free colored crystalline glaze and a preparation method thereof. The crystalline glaze of the present invention has the advantages of health and safety, stable glaze color, high yield rate, etc., which facilitates the realization of production stability and controllability.

[0004] The technical solution of the present invention is as follows:

[0005] One of the objects of the present invention is to provide a lead-free colored crystalline glaze, which is composed of the following raw materials in parts by weight: 40-48 parts of SiO2, 11-13 parts of Al2O3, 3.8-4.6 parts of K2O, 1.3-1.6 parts of Na2O, 0-1.5 parts of CaO, 0-1.9 parts of BaO, 0-1.5 parts of ZnO, 0-1.5 parts of TiO2, 0-1 parts of CoO, 0-2 parts of Fe2O3, 8-12 parts of MnO, 21-30 parts of Bi2O3, and 0.5-2 parts of V2O5.

[0006] Furthermore, a binder is added to the crystalline glaze.

[0007] Furthermore, the binder accounts for 0.1-0.2% of the total mass of the crystalline glaze.

[0008] The second object of the present invention is to provide a method for preparing a lead-free colored crystalline glaze, comprising the following steps:

[0009] S1: Weigh each raw material according to a set ratio, add water and grind to obtain glaze water;

[0010] S2: applying the glaze prepared in step S1 to the surface of the bisque fired body by spraying glaze, the spraying technique adopts a fine-point to medium-point water glaze atomization effect, and glazing is applied 2-3 times;

[0011] S3: After the glaze-sprayed body is dried, it is placed in a kiln, a relatively low heating rate is used in the heating stage, and a firing cycle of 8-10 hours is adopted, the maximum sintering temperature is controlled to be 1180-1230°C, and after the firing is completed, it is slowly cooled out of the kiln to obtain the lead-free colored crystalline glaze.

[0012] Furthermore, the raw material of the bisque-fired body is mainly white porcelain clay.

[0013] Furthermore, in step S1, the glaze water has a 10,000-pore sieve residue of 0.3-0.6%, and a water-glaze specific gravity of 1.53-1.55.

[0014] Furthermore, in step S2, the thickness of the glaze layer after glazing is controlled to be 0.4-0.6 mm.

[0015] Furthermore, in step S2, the specific operation of glazing is: spraying glaze on the entire bisque-fired body twice, and increasing the thickness of the glaze layer on the upper body to three times.

[0016] Furthermore, in step S3, the specific operation of sintering at a lower heating rate in the heating section is: 800-950°C, the heating rate is 1-1.5°C / min; 950-1050°C, the heating rate is 0.8-1.0°C / min; 1050°C-maximum sintering temperature, the heating rate is 0.5-0.8°C / min, and the maximum sintering temperature is kept at 20-40 minutes.

[0017] Furthermore, in step S3, the specific operation of the slow cooling out of the kiln is: from the end of firing to the process of dropping to 900°C, a natural cooling method is adopted, and the kiln door and the vents are both in a closed state; when the temperature in the kiln drops below 900°C, the temperature is lowered by gradually opening the vents and loosening the kiln door.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention provides a lead-free colored crystalline glaze, which uses silicon dioxide and aluminum oxide as basic glazes, potassium oxide and sodium oxide as fluxes, bismuth oxide, manganese oxide, and vanadium pentoxide as main crystal phases, and calcium oxide, barium oxide, zinc oxide, and titanium oxide as crystallizers, wherein cobalt oxide and iron oxide have both crystallization-promoting and auxiliary color-developing effects. The present invention replaces the traditional lead-based crystallization system with a crystallization system composed of bismuth, vanadium, and manganese, and promotes the growth of glaze layer crystals through the coordination of other components. Under lead-free conditions, the safety of daily-use porcelain is guaranteed, and crystals of different types and contents are formed, achieving the effect of colored crystallization of daily-use porcelain glaze, so that the glaze presents a glaze texture with multiple colors such as gold, purple, green, and blue, highlighting the variability and metallic feel of the glaze, and reducing the harm to operators during the processing process, ensuring the health of users.

[0020] 2. The present invention provides a method for preparing a lead-free colored crystalline glaze, which reduces the generation of glaze bubbles by adopting a lower heating rate in the heating stage, and controls the maximum sintering temperature between 1180-1230°C to ensure that the glaze layer still retains an appropriate number of seed crystals after passing through the high temperature stage. The slow cooling firing process adopted by the present invention can promote the continuation and smooth progress of the crystallization reaction, and ensure that the glazed crystals can achieve a gradual effect at the thickness transition of the glaze layer after sintering. If too high a temperature is used for sintering or a fast cooling process is used, the generation of crystallization will be suppressed or even disappear. The preparation method provided by the present invention reduces the generation of glaze bubbles while ensuring the glaze effect, and can achieve a transition in glaze texture by controlling the glazing thickness.

[0021] 3. In the present invention, by using a bisque-fired body mainly made of white porcelain clay, the crystallization and glass-like contrast effects of the glaze color can be further improved.

[0022] 4. In the present invention, by spraying glaze three times on the upper part of the bisque-fired body, the thickness of the glaze layer is transitioned from three layers on the upper part of the body to two layers, which can solve the problem of high glaze fluidity and avoid glaze sticking to the bottom of the body. The thickness change of the glaze layer brings a gradual effect, thereby improving the aesthetics of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a lead-free colored crystalline glaze provided by the present invention;

[0024] Figure 2 This is a partial glaze image of the lead-free colored crystalline glaze prepared in Example 1 of the present invention;

[0025] Figure 3 This is a partial glaze image of the lead-free colored crystalline glaze prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0026] The following is in conjunction with the preferred embodiment and with reference to the attached Figure 1 , the present invention is further described. The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values; for numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein; the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels; the experimental methods in the following examples, unless otherwise specified, are all conventional methods.

[0027] Example 1

[0028] This embodiment provides a lead-free colored crystalline glaze, which is composed of the following raw materials in parts by weight: 40 parts of SiO2, 13 parts of Al2O3, 3.8 parts of K2O, 1.6 parts of Na2O, 1.9 parts of BaO, 1.5 parts of ZnO, 1 part of CoO, 8 parts of MnO, 30 parts of Bi2O3, and 0.5 parts of V2O5.

[0029] In this embodiment, a binder is further added to the crystalline glaze, and the binder accounts for 0.2% of the total mass of the crystalline glaze.

[0030] This embodiment also provides a method for preparing a lead-free colored crystalline glaze, comprising the following steps:

[0031] S1: Weigh each raw material according to a set ratio, add water and grind to obtain glaze water;

[0032] In this embodiment, the glaze water has a 0.3% sieve residue and a water-glaze specific gravity of 1.55;

[0033] S2: applying the glaze prepared in step S1 to the surface of the bisque fired body by spraying glaze, the spraying technique adopts a fine-point to medium-point water glaze atomization effect, and glazing is applied 2-3 times;

[0034] In this embodiment, the raw material of the bisque-fired body is white porcelain clay, and the thickness of the glaze layer after glazing is controlled at 0.4 mm. The specific operation of glazing is: the bisque-fired body is sprayed with glaze twice as a whole, and the thickness of the glaze layer of the upper body is increased to three times.

[0035] S3: After the glaze-sprayed body is dried, it is placed in a kiln, a relatively low heating rate is adopted in the heating stage, and a firing cycle of 10 hours is adopted, the maximum sintering temperature is controlled to be 1180°C, and after the firing is completed, it is slowly cooled out of the kiln to obtain the lead-free colored crystalline glaze.

[0036] In this embodiment, the specific operation of sintering at a lower heating rate in the heating stage is: 800-950°C, the heating rate is 1°C / min; 950-1050°C, the heating rate is 0.8°C / min; 1050-1180°C, the heating rate is 0.5°C / min, and keeping at 1180°C for 40 minutes.

[0037] In this embodiment, the specific operation of the slow cooling out of the kiln is: from the end of firing to the process of dropping to 900°C, a natural cooling method is adopted, and the kiln door and the vents are kept in a closed state; when the temperature in the kiln drops below 900°C, the temperature is lowered by gradually opening the vents and loosening the kiln door.

[0038] The colored crystalline glaze prepared in this embodiment is as follows Figure 1 shown.

[0039] Example 2

[0040] This embodiment provides a lead-free colored crystalline glaze, which is composed of the following raw materials in parts by weight: 48 parts of SiO2, 11 parts of Al2O3, 4.6 parts of K2O, 1.3 parts of Na2O, 1.5 parts of CaO, 1.5 parts of TiO2, 2 parts of Fe2O3, 12 parts of MnO, 21 parts of Bi2O3, and 2 parts of V2O5.

[0041] In this embodiment, a binder is further added to the crystalline glaze, and the binder accounts for 0.1% of the total mass of the crystalline glaze.

[0042] This embodiment also provides a method for preparing a lead-free colored crystalline glaze, comprising the following steps:

[0043] S1: Weigh each raw material according to a set ratio, add water and grind to obtain glaze water;

[0044] In this embodiment, the glaze water has a sieve residue of 0.6% and a water-glaze specific gravity of 1.53;

[0045] S2: applying the glaze prepared in step S1 to the surface of the bisque fired body by spraying glaze, the spraying technique adopts a fine-point to medium-point water glaze atomization effect, and glazing is applied 2-3 times;

[0046] In this embodiment, the raw material of the bisque-fired body is white porcelain clay, and the thickness of the glaze layer after glazing is controlled at 0.6 mm. The specific operation of glazing is: the bisque-fired body is sprayed with glaze twice as a whole, and the thickness of the glaze layer of the upper body is increased to three times.

[0047] S3: After the glaze-sprayed body is dried, it is placed in a kiln, a relatively low heating rate is adopted in the heating stage, and a firing cycle of 8 hours is adopted, the maximum sintering temperature is controlled to be 1230°C, and after the firing is completed, it is slowly cooled out of the kiln to obtain the lead-free colored crystalline glaze.

[0048] In this embodiment, the specific operation of sintering at a lower heating rate in the heating stage is: 800-950°C, the heating rate is 1.2°C / min; 950-1050°C, the heating rate is 0.9°C / min; 1050-1230°C, the heating rate is 0.7°C / min, and keeping at 1230°C for 20 minutes.

[0049] In this embodiment, the specific operation of the slow cooling out of the kiln is: from the end of firing to the process of dropping to 900°C, a natural cooling method is adopted, and the kiln door and the vents are kept in a closed state; when the temperature in the kiln drops below 900°C, the temperature is lowered by gradually opening the vents and loosening the kiln door.

[0050] Example 3

[0051] The present embodiment provides a lead-free colored crystalline glaze, which is composed of the following raw materials in parts by weight: 45 parts of SiO2, 12 parts of Al2O3, 4.1 parts of K2O, 1.4 parts of Na2O, 1.0 parts of CaO, 1.0 parts of BaO, 1.5 parts of ZnO, 1.1 parts of TiO2, 0.5 parts of CoO, 1 part of Fe2O3, 11 parts of MnO, 27 parts of Bi2O3, and 1.4 parts of V2O5.

[0052] In this embodiment, a binder is further added to the crystalline glaze, and the binder accounts for 0.15% of the total mass of the crystalline glaze.

[0053] This embodiment also provides a method for preparing a lead-free colored crystalline glaze, comprising the following steps:

[0054] S1: Weigh each raw material according to a set ratio, add water and grind to obtain glaze water;

[0055] In this embodiment, the glaze water has a 0.5% sieve residue and a water-glaze specific gravity of 1.54;

[0056] S2: applying the glaze prepared in step S1 to the surface of the bisque fired body by spraying glaze, the spraying technique adopts a fine-point to medium-point water glaze atomization effect, and glazing is applied 2-3 times;

[0057] In this embodiment, the raw material of the bisque-fired body is white porcelain clay, and the thickness of the glaze layer after glazing is controlled at 0.5 mm. The specific operation of glazing is: the bisque-fired body is sprayed with glaze twice as a whole, and the thickness of the glaze layer of the upper body is increased to three times.

[0058] S3: After the glaze-sprayed body is dried, it is placed in a kiln, a relatively low heating rate is adopted in the heating stage, and a firing cycle of 9 hours is adopted, the maximum sintering temperature is controlled to be 1210°C, and after the firing is completed, it is slowly cooled out of the kiln to obtain the lead-free colored crystalline glaze.

[0059] In this embodiment, the specific operation of sintering at a lower heating rate in the heating stage is: 800-950°C, the heating rate is 1.5°C / min; 950-1050°C, the heating rate is 1.0°C / min; 1050-1210°C, the heating rate is 0.8°C / min, and keeping at 1210°C for 30 minutes.

[0060] In this embodiment, the specific operation of the slow cooling out of the kiln is: from the end of firing to the process of dropping to 900°C, a natural cooling method is adopted, and the kiln door and the vents are kept in a closed state; when the temperature in the kiln drops below 900°C, the temperature is lowered by gradually opening the vents and loosening the kiln door.

[0061] In the present invention, relief texture decoration can also be used to further differentiate the thickness of the glaze layer due to the influence of glaze flow, thereby enhancing the color contrast of the glaze layer after sintering.

[0062] It can be seen from the above embodiments that the present invention uses silicon dioxide and aluminum oxide as basic glazes, potassium oxide and sodium oxide as fluxes, bismuth oxide, manganese oxide, and vanadium pentoxide as main crystal phases, and calcium oxide, barium oxide, zinc oxide, and titanium oxide as crystallizers, wherein cobalt oxide and iron oxide simultaneously have a crystallization promoting effect and an auxiliary coloring effect. The present invention replaces the traditional lead-based crystallization system with a crystallization system composed of bismuth, vanadium, and manganese, and promotes the growth of glaze layer crystals through the coordination of other components. Under lead-free conditions, the safety of daily-use porcelain is ensured, and crystals of different types and contents are formed, achieving the effect of colored crystallization of the glaze surface of daily-use porcelain, so that the glaze surface presents a glaze texture with multiple colors such as gold, purple, green, and blue, highlighting the variability and metallic feel of the glaze surface, and reducing the harm to operators during the processing process, ensuring the health of users.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A lead-free colored crystalline glaze, characterized in that: It is composed of the following raw materials in parts by weight: 40-48 parts of SiO2, 11-13 parts of Al2O3, 3.8-4.6 parts of K2O, 1.3-1.6 parts of Na2O, 0-1.5 parts of CaO, 0-1.9 parts of BaO, 0-1.5 parts of ZnO, 0-1.5 parts of TiO2, 0-1.5 parts of CoO, 0-1 parts of Fe2O3, 0-2 parts of MnO, 8-12 parts of Bi2O3, 21-30 parts of V2O5, and 0.5-2 parts of V2O5.

2. The lead-free colored crystalline glaze according to claim 1, characterized in that: A binder is also added to the crystalline glaze.

3. The lead-free colored crystalline glaze according to claim 2, characterized in that: The binder accounts for 0.1-0.2% of the total mass of the crystalline glaze.

4. A method for preparing a lead-free colored crystalline glaze according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: Weigh each raw material according to a set ratio, add water and grind to obtain glaze water; S2: applying the glaze prepared in step S1 to the surface of the bisque fired body by spraying glaze, the spraying technique adopts a fine-point to medium-point water glaze atomization effect, and glazing is applied 2-3 times; S3: After the glaze-sprayed body is dried, it is placed in a kiln, a relatively low heating rate is used in the heating stage, and a firing cycle of 8-10 hours is adopted, the maximum sintering temperature is controlled to be 1180-1230°C, and after the firing is completed, it is slowly cooled out of the kiln to obtain the lead-free colored crystalline glaze.

5. The method for preparing a lead-free colored crystalline glaze according to claim 4, characterized in that: The raw material of the bisque-fired body is mainly white porcelain clay.

6. The method for preparing a lead-free colored crystalline glaze according to claim 4, characterized in that: In step S1, the glaze water has a 10,000-pore sieve residue of 0.3-0.6%, and a water-glaze specific gravity of 1.53-1.

55.

7. The method for preparing a lead-free colored crystalline glaze according to claim 4, characterized in that: In step S2, the thickness of the glaze layer after glazing is controlled to be 0.4-0.6 mm.

8. The method for preparing a lead-free colored crystalline glaze according to claim 4, characterized in that: In step S2, the specific operation of glazing is: spraying glaze on the entire bisque-fired body twice, and increasing the thickness of the glaze layer on the upper body to three times.

9. The method for preparing a lead-free colored crystalline glaze according to claim 4, characterized in that: In step S3, the specific operation of sintering at a lower heating rate in the heating section is: 800-950°C, the heating rate is 1-1.5°C / min; 950-1050°C, the heating rate is 0.8-1.0°C / min; 1050°C-highest sintering temperature, the heating rate is 0.5-0.8°C / min, and the highest sintering temperature is kept for 20-40 minutes.

10. The method for preparing a lead-free colored crystalline glaze according to claim 4, characterized in that: In step S3, the specific operation of the slow cooling out of the kiln is: from the end of firing to the process of dropping to 900°C, a natural cooling method is adopted, and the kiln door and the vents are kept in a closed state; when the temperature in the kiln drops below 900°C, the temperature is lowered by gradually opening the vents and loosening the kiln door.

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