A multi-depth effect glazed tile mixed firing process

Abstract

This invention relates to the field of architectural ceramics technology, and more particularly to a multi-layered glaze tile firing process, comprising: A) preparing multiple glaze blanks, wherein the glaze blanks include at least one of small-gray-scale glaze blanks, medium-gray-scale glaze blanks, and large-gray-scale glaze blanks; B) sequentially conveying the multiple glaze blanks to the brick-feeding position of the high-capacity kiln, and firing them at a firing temperature ≤1100℃ and a firing cycle ≤30min. The small-gray-scale glaze blank comprises a body layer, a medium-expansion surface glaze, and an inkjet printing amount <4.8g / m². 2 The colored ink and fully polished glaze, the medium gray glaze body includes the body layer, the high-expansion surface glaze, and the inkjet volume is 4.8–9.6 g / m. 2 Colored inks and fully polished glaze, large grayscale glaze body including body layer, high-expansion surface glaze, inkjet volume > 9.6g / m 2 And ≤14.4g / m 2 The proposed solution utilizes colored inks and fully polished glazes. It presents a multi-depth glazed tile firing process that enables low-temperature, rapid firing of fully polished glazed tiles with different shades of gray within the same kiln. This process not only satisfies the physical and chemical properties of fully polished glazes but also balances the tile shape.

Description

Technical Field

[0001] This invention relates to the field of building ceramics technology, and in particular to a mixed firing process for glazed tiles with multiple depth effects. Background Technology

[0002] In order to reduce unit costs and enhance market competitiveness through economies of scale, and to meet the industry's demand for large-scale production, existing building ceramics manufacturers are generally equipped with large-capacity production lines, with a daily production capacity of up to 40,000 cubic meters. 2 The core equipment of high-capacity production lines is mainly ultra-large wide-body kilns (hereinafter referred to as "high-capacity kilns"), which typically have three brick feeding positions in the width direction corresponding to three glaze lines, thereby improving production efficiency and output.

[0003] Generally, large-capacity kilns can only fire one type of ceramic tile at a time. However, as market competition intensifies, there are fewer and fewer single-category products with large orders and more and more products with small orders. Among these small-order products, there are generally different requirements such as body whiteness, body water absorption rate, body powder granulation process, size, thickness, glaze effect, and depth of product pattern.

[0004] Currently, large-capacity kilns are struggling to keep up with production schedules for smaller orders, leading to shutdowns on many production lines housing these large kilns. The main reasons are as follows:

[0005] First, small orders result in fewer products, leading to frequent switching of large-capacity kilns and significant losses during switching. This also easily causes empty kilns, affecting the stability of the firing curve within the kiln and thus impacting product quality.

[0006] Secondly, the processes for different products vary significantly, making it impossible for the kiln's firing curves to match the various products, which also affects product quality.

[0007] Therefore, how to achieve co-firing of various ceramic tile products in large-capacity kilns is a difficult problem for the building ceramics industry under the current market conditions.

[0008] Generally, darker (higher grayscale) ceramic tile products have a higher ink spray volume, while lighter (lower grayscale) ceramic tile products have a lower ink spray volume. Furthermore, the inks commonly used in the architectural ceramics industry contain a large amount of fluxing metal oxides, which participate in the glaze reaction during firing, causing the glaze to exhibit a weak low-temperature fluxing effect, resulting in overall deformation, tilting, and convex deformation of the tile product. Therefore, even with the same effect glaze (i.e., the glaze on the surface of glazed tiles), different ink spray volumes will lead to different degrees of deformation in the corresponding tile products. In the past, during non-mixed firing periods, the kiln was usually adjusted to accommodate the formula / process, i.e., by adjusting kiln parameters (such as kiln surface temperature, kiln bottom temperature, firing curve, etc.) to compensate for the impact of ink spray volume on the overall deformation of the product. However, in mixed firing processes of multiple tile products, if the kiln is adjusted to accommodate the deformation of one type of product, then the other types of products will inevitably be affected by the kiln, resulting in deformation or even other defects, thereby reducing the production quality of the other types of products. Summary of the Invention

[0009] The purpose of this invention is to propose a multi-depth and shallow-effect glazed tile co-firing process that enables low-temperature rapid firing of fully polished glazed tiles with different ash levels in the same kiln. Moreover, the fired tile products not only meet the physicochemical properties of fully polished glaze, but also balance the tile shape of fully polished glazed tile products corresponding to different ash levels, overcoming the shortcomings of the prior art.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] A multi-depth glazed tile co-firing process, suitable for high-capacity kilns, wherein the high-capacity kiln has three brick-feeding positions in the width direction, the co-firing process includes the following steps:

[0012] A. Prepare multiple glaze blanks, wherein the glaze blanks include at least one of small grayscale glaze blanks, medium grayscale glaze blanks, and large grayscale glaze blanks;

[0013] B. Multiple glazed blanks are sequentially conveyed to the brick feeding position of the high-capacity kiln and fired in an environment with a firing temperature ≤1100℃ and a firing cycle ≤30min.

[0014] In step A, the small grayscale glaze blank includes a blank layer, and a medium-expansion glaze, colored ink, and fully polished glaze applied sequentially from bottom to top on the top surface of the blank layer; wherein, the inkjet amount of the colored ink is <4.8g / m³. 2 The amount of the medium-expansion glaze applied is 420-480 g / m². 2 ;

[0015] The medium-gray glaze blank includes a blank layer, and a high-expansion surface glaze, colored ink, and fully polished glaze applied sequentially from bottom to top on the top surface of the blank layer; wherein, the inkjet amount of the colored ink is 4.8–9.6 g / m³. 2 The application amount of the high-expansion glaze is 330–390 g / m³. 2 ;

[0016] The high-grayscale glaze blank includes a blank layer, and a high-expansion surface glaze, colored ink, and fully polished glaze applied sequentially from bottom to top on the top surface of the blank layer; wherein, the inkjet volume of the colored ink is >9.6g / m³. 2 And ≤14.4g / m 2 The application amount of the high-expansion glaze is 420-480 g / m³. 2 ;

[0017] In step B, the firing curve of the high-capacity kiln includes a preheating section, a preheating section, a medium-temperature section, a high-temperature section, a rapid cooling section, and a slow cooling section: In the preheating section, the surface temperature rises from room temperature to 950°C, and the bottom temperature rises from room temperature to 1100°C, taking 3.5–3.7 minutes; in the preheating section, the surface temperature rises from 950°C to 1110°C, and the bottom temperature drops from 1100°C to 1060°C, taking 2–2.2 minutes; in the medium-temperature section, the surface temperature rises from 1110°C to 1203°C, and the bottom temperature… The temperature rises from 1060℃ to 1226℃ in 7.7–7.9 minutes; the surface temperature of the high-temperature section is maintained at 1203℃ and the bottom temperature at 1226℃ in 4.3–4.5 minutes; the surface temperature of the rapid cooling section drops from 1203℃ to 570℃ and the bottom temperature drops from 1226℃ to 300℃ in 4.7–4.9 minutes; the surface temperature of the slow cooling section drops from 570℃ to room temperature and the bottom temperature drops from 300℃ to room temperature in 6.4–6.6 minutes.

[0018] Preferably, the fully polished glaze of the small grayscale glaze blank, the fully polished glaze of the medium grayscale glaze blank, and the fully polished glaze of the large grayscale glaze blank are the same; the raw materials of the fully polished glaze are composed of albite, kaolin, calcined clay, dolomite, quartz, calcite, alumina, zinc oxide, and strontium carbonate.

[0019] The silicon-to-aluminum ratio of the fully polished glaze is 3.0 to 3.2, and the Na2O content in the fully polished glaze is 4.2 to 5.2% and the SrO content is 3.3 to 4.3% by mass percentage.

[0020] Preferably, the chemical composition of the fully polished glaze, by mass percentage, includes SiO2 45.0–49.0%, Al2O3 14.7–15.6%, Fe2O3 0.1–0.2%, TiO2 0.05–0.1%, CaO 8.5–9.5%, MgO 2.5–3.5%, K2O 0.1–0.3%, Na2O 4.2–5.2%, ZnO 3.4–4.4%, SrO 3.3–4.3%, and loss on ignition 8.0–12.0%.

[0021] Preferably, the raw materials for the fully polished glaze are composed of 52.5% sodium feldspar, 6% kaolin, 6% calcined clay, 15% dolomite, 2% quartz, 7% calcite, 2% alumina, 4% zinc oxide and 5.5% strontium carbonate, by mass percentage.

[0022] Preferably, the glaze application rate of the fully polished glaze is 420–480 g / m². 2 .

[0023] Preferably, after firing in step B, the water absorption rate of the body layer of the small gray glaze blank, the body layer of the medium gray glaze blank, and the body layer of the large gray glaze blank are all ≤0.5% by mass percentage.

[0024] The body layers of the small gray glaze blank, the medium gray glaze blank, and the large gray glaze blank are all pressed from low moisture-absorbing powder, and the low moisture-absorbing powder is obtained by a wet powder making process.

[0025] The chemical composition of the low-hygroscopic powder includes Al2O3, CaO, MgO, K2O and Na2O. By mass percentage, the content of Al2O3 in the low-hygroscopic powder is 17.2-18.2%, the total content of CaO, MgO, K2O and Na2O is 5.6-6.6%, the content of CaO is ≥0.8%, the content of MgO is ≥1.8%, the content of K2O is ≥1.5%, and the content of Na2O is ≥1.5%.

[0026] Preferably, the chemical composition of the low-hygroscopic powder, by mass percentage, includes 66.4–67.5% SiO2, 17.2–18.2% Al2O3, 1.6–2.7% Fe2O3, 0.3–0.5% TiO2, 0.8–1.2% CaO, 1.8–2.3% MgO, 1.5–1.6% K2O, 1.5–1.8% Na2O, and 4.8–5.5% loss on ignition.

[0027] Preferably, the blank layers of the small gray glaze blank, the medium gray glaze blank, and the large gray glaze blank are all 800mm×800mm in size, and in the high-capacity kiln, the front edge of all blank layers along the conveying direction forms an angle with the width direction of the high-capacity kiln, and the angle of the angle is 5 to 11°.

[0028] Preferably, the dimensions of the body layer of the small gray glaze blank, the body layer of the medium gray glaze blank, and the body layer of the large gray glaze blank are all 750mm×1500mm, and in the high-capacity kiln, the short edge of all body layers forms an angle II with the width direction of the high-capacity kiln, and the angle of the angle II is 7 to 13°.

[0029] Preferably, the coefficient of thermal expansion of the medium-expansion glaze is (7.3~7.5)×10⁻¹⁰. -6 / ℃, according to the mass fraction, the raw materials of the medium-expansion glaze include 38-42 parts of sodium feldspar, 9-11 parts of kaolin, 4-6 parts of quartz, 9-11 parts of nepheline, 12-16 parts of alumina, 10-14 parts of potassium feldspar, 5-7 parts of calcined clay, 2-4 parts of calcined talc, and 10-14 parts of zirconium silicate.

[0030] The coefficient of thermal expansion of the high-expansion glaze is (7.9~8.1)×10. -6 / ℃, according to the mass fraction, the raw materials of the high-expansion glaze include 36-40 parts of albite, 9-11 parts of kaolin, 19-22 parts of quartz, 14-16 parts of nepheline, 14-16 parts of alumina, 1-3 parts of calcined talc and 10-14 parts of zirconium silicate.

[0031] The technical solution provided by this invention may include the following beneficial effects:

[0032] This solution proposes a multi-depth and shallow-effect glazed tile co-firing process, which enables low-temperature rapid firing of fully polished glazed tiles with different ash levels in the same kiln. The fired tile products not only meet the physical and chemical properties of fully polished glaze, but also balance the tile shape of fully polished glazed tiles corresponding to different ash levels, overcoming the shortcomings of existing technologies. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the arrangement of 800-size glazed blanks in a multi-depth and shallow glazed tile co-firing process according to the present invention.

[0034] Figure 2 This is a schematic diagram of the arrangement of 715-size glazed blanks in a multi-depth and shallow-effect glazed tile co-firing process according to the present invention. Detailed Implementation

[0035] This technical solution provides a multi-depth glazed tile co-firing process, suitable for high-capacity kilns, wherein the high-capacity kiln has three brick feeding positions in the width direction. The co-firing process includes the following steps:

[0036] A. Prepare multiple glaze blanks, wherein the glaze blanks include at least one of small grayscale glaze blanks, medium grayscale glaze blanks, and large grayscale glaze blanks;

[0037] B. Multiple glazed blanks are sequentially conveyed to the brick feeding position of the high-capacity kiln and fired in an environment with a firing temperature ≤1100℃ and a firing cycle ≤30min.

[0038] In step A, the small grayscale glaze blank includes a blank layer, and a medium-expansion glaze, colored ink, and fully polished glaze applied sequentially from bottom to top on the top surface of the blank layer; wherein, the inkjet amount of the colored ink is <4.8g / m³. 2 The amount of the medium-expansion glaze applied is 420-480 g / m². 2 ;

[0039] The medium-gray glaze blank includes a blank layer, and a high-expansion surface glaze, colored ink, and fully polished glaze applied sequentially from bottom to top on the top surface of the blank layer; wherein, the inkjet amount of the colored ink is 4.8–9.6 g / m³. 2 The application amount of the high-expansion glaze is 330–390 g / m³. 2 ;

[0040] The high-grayscale glaze blank includes a blank layer, and a high-expansion surface glaze, colored ink, and fully polished glaze applied sequentially from bottom to top on the top surface of the blank layer; wherein, the inkjet volume of the colored ink is >9.6g / m³. 2 And ≤14.4g / m 2 The application amount of the high-expansion glaze is 420-480 g / m³. 2 ;

[0041] In step B, the firing curve of the high-capacity kiln includes a preheating section, a preheating section, a medium-temperature section, a high-temperature section, a rapid cooling section, and a slow cooling section: In the preheating section, the surface temperature rises from room temperature to 950°C, and the bottom temperature rises from room temperature to 1100°C, taking 3.5–3.7 minutes; in the preheating section, the surface temperature rises from 950°C to 1110°C, and the bottom temperature drops from 1100°C to 1060°C, taking 2–2.2 minutes; in the medium-temperature section, the surface temperature rises from 1110°C to 1203°C, and the bottom temperature… The temperature rises from 1060℃ to 1226℃ in 7.7–7.9 minutes; the surface temperature of the high-temperature section is maintained at 1203℃ and the bottom temperature at 1226℃ in 4.3–4.5 minutes; the surface temperature of the rapid cooling section drops from 1203℃ to 570℃ and the bottom temperature drops from 1226℃ to 300℃ in 4.7–4.9 minutes; the surface temperature of the slow cooling section drops from 570℃ to room temperature and the bottom temperature drops from 300℃ to room temperature in 6.4–6.6 minutes.

[0042] To achieve the mixed firing of fully polished glazed ceramic tiles with different gray levels in the same kiln, this technical solution proposes a multi-depth glaze tile mixed firing process. On the one hand, it achieves low-temperature rapid firing (specifically, a firing temperature ≤1100℃ and a firing cycle ≤30min), which helps reduce energy consumption and carbon emissions. On the other hand, it balances the tile shapes of the three types of ceramic tiles while ensuring the physicochemical properties of fully polished glazed ceramic tiles are achieved. It should be noted that the firing temperature in this solution is measured using a British PULSE thermometer ring, reflecting the equivalent temperature corresponding to the comprehensive thermal effects experienced at the location where the thermometer ring is placed during the entire firing process.

[0043] Since fully polished glazed tiles, as the surface layer of glazed ceramic tiles, generally need to consider physical and chemical properties such as gloss, wear resistance, acid and alkali resistance, color development, and stain resistance. Therefore, in order to reduce the design difficulty of the glaze and solve the technical problem that "different inkjet amounts lead to different deformation degrees in the corresponding ceramic tile products," and to balance the tile shape of fully polished glazed ceramic tile products corresponding to different ash levels, this solution first adjusts the surface temperature curve and bottom temperature curve of the kiln so that the obtained firing curve can simultaneously match the firing characteristics of three ash levels. Then, this solution also introduces surface glazes with different expansion coefficients and different glaze application amounts to match the three glaze blanks with different inkjet amounts, respectively, to compensate for the tile shape of the three fully polished glazed ceramic tile products with different inkjet amounts, so as to adapt to firing in the same kiln environment, ensuring that the difference in deformation after firing is small and meets quality standards.

[0044] It should be noted that commonly used color inks in the architectural ceramics industry contain a large amount of fluxing metal oxides, which participate in the glaze reaction during firing, causing the glaze to exhibit a weak low-temperature fluxing effect. This results in overall deformation, tilting, and convexity of the tile product. To counteract this effect, this solution uses a high-expansion coefficient top glaze for matching, and adjusts the application amount of the high-expansion top glaze according to the inkjet volume. This balances the shrinkage stress caused by the fluxing effect in the area where the color ink is applied during firing, reducing tile deformation.

[0045] It should be further noted that the mixed firing process in this scheme refers to the simultaneous firing of glaze blanks of various ceramic tile products in the same kiln in the same batch, and the placement of the glaze blanks in the high-capacity kiln in step B is not limited. Specifically, small gray-scale glaze blanks, medium gray-scale glaze blanks, and large gray-scale glaze blanks can be placed in three brick-feeding positions in the same width direction in the high-capacity kiln, while the three brick-feeding positions in other width directions are the same, i.e., the placement method in the embodiment; or, three small gray-scale glaze blanks can be placed in three brick-feeding positions in the same width direction in the high-capacity kiln, then three medium gray-scale glaze blanks can be placed in three brick-feeding positions in the next width direction, and then three large gray-scale glaze blanks can be placed in three brick-feeding positions in the next width direction, and so on; or, two small gray-scale glaze blanks and one medium gray-scale glaze blank can be placed in three brick-feeding positions in the same width direction in the high-capacity kiln, then one medium gray-scale glaze blank and two large gray-scale glaze blanks can be placed in three brick-feeding positions in the next width direction, and so on.

[0046] To further clarify, the fully polished glaze of the small grayscale glaze blank, the fully polished glaze of the medium grayscale glaze blank, and the fully polished glaze of the large grayscale glaze blank are the same; the raw materials of the fully polished glaze are composed of albite, kaolin, calcined clay, dolomite, quartz, calcite, alumina, zinc oxide, and strontium carbonate.

[0047] The silicon-to-aluminum ratio of the fully polished glaze is 3.0 to 3.2, and the Na2O content in the fully polished glaze is 4.2 to 5.2% and the SrO content is 3.3 to 4.3% by mass percentage.

[0048] Polished glaze is an almost molten glass structure. The raw material scheme of this solution is a raw transparent glaze, which is basically not opaque, has high light transmittance, strong penetration, and good color development. It also has physical and chemical properties such as anti-fouling, wear resistance, and corrosion resistance, and has a short firing time.

[0049] Compared to traditional transparent fully polished glazes, this design selects albite, an alkali metal, as the main flux, and dolomite, strontium carbonate, and zinc oxide as alkaline earth metals. Dolomite is a very inexpensive calcium and magnesium raw material among natural minerals; zinc oxide contributes to the excellent color development of the glaze formula.

[0050] During firing, strontium carbonate can replace CaO and ZnO in equal amounts in the formula, thereby further increasing its fluxing effect and fluidity. Furthermore, strontium carbonate decomposes into SrO (SrCO3→SrO+CO2↑) within the temperature range of 800-1000℃. SrO can react with SiO2 to produce low-melting-point strontium silicate (SrSiO3), accelerating the vitrification of the glaze and meeting the requirements of low-temperature rapid firing. Additionally, the raw material formula in this solution is a low-viscosity formula (i.e., with lower high-temperature viscosity), allowing the micropores created by CO2 from the early decomposition of strontium silicate to be quickly filled by the low-viscosity melt, forming a pore-free surface and achieving surface densification. Simultaneously, the low-viscosity formula also facilitates rapid venting of other layers in the ceramic tile product (such as the body layer). It should be noted that since strontium silicate is completely decomposed before 1000℃, even under the low-temperature rapid firing mechanism of this solution, pinholes in the glaze caused by residual CO2 can be eliminated.

[0051] Furthermore, SrO has a refractive index of 1.83, while strontium silicate, formed during the vitrification reaction, has a refractive index of 1.65. The introduction of strontium carbonate can also enhance the glaze gloss, reduce scattering, and create a mirror effect. 2+ Occupying the gaps in the [SiO4] network can hinder the nucleation and growth of silicate crystals (such as wollastonite, diopside, etc.), reduce glaze opacity or crystal spots, and is very beneficial for maintaining the high transparency of the glaze layer.

[0052] Furthermore, strontium carbonate is also a color-developing agent; SrO can replace part of CaO, reducing Cr content. 3+ It reduces oxidation tendency and stabilizes pink color; and during the experimental debugging process, it was found that this system, when combined with zinc oxide, is also very beneficial for red color development.

[0053] In the chemical composition of the fully polished glaze, this scheme also limits the silicon-to-aluminum ratio (SiO2 / Al2O3) and optimizes the content of fluxing components Na2O and SrO, thus forming a sodium-strontium system glaze in terms of chemical composition. Traditional fully polished glazes are generally potassium-barium system glazes, which are sensitive to the silicon content in their chemical composition. If the corrosion resistance of the glaze is improved by increasing the silicon content, the glaze surface porosity will increase, thereby reducing the anti-fouling performance of the glaze. Compared with traditional potassium-barium system glazes, the sodium-strontium system glaze can simultaneously increase the aluminum and silicon content of the glaze, while taking into account both the corrosion resistance and anti-fouling performance of the glaze.

[0054] To further clarify, the chemical composition of the fully polished glaze, by mass percentage, includes SiO2 45.0–49.0%, Al2O3 14.7–15.6%, Fe2O3 0.1–0.2%, TiO2 0.05–0.1%, CaO 8.5–9.5%, MgO 2.5–3.5%, K2O 0.1–0.3%, Na2O 4.2–5.2%, ZnO 3.4–4.4%, SrO 3.3–4.3%, and loss on ignition 8.0–12.0%.

[0055] Furthermore, in order to ensure the stability of the glaze during the firing process and to meet the performance requirements of this application, this solution proposes an example of the chemical composition of a specific fully polished glaze.

[0056] To further explain, the raw materials of the fully polished glaze, by mass percentage, consist of 52.5% sodium feldspar, 6% kaolin, 6% calcined clay, 15% dolomite, 2% quartz, 7% calcite, 2% alumina, 4% zinc oxide, and 5.5% strontium carbonate.

[0057] Furthermore, this plan also proposes a specific raw material ratio scheme for fully polished glazed ceramic.

[0058] To further clarify, the glaze application rate of the fully polished glaze is 420–480 g / m². 2 .

[0059] To further clarify, based on mass percentage, after firing in step B, the water absorption rate of the body layer of the small grayscale glaze blank, the body layer of the medium grayscale glaze blank, and the body layer of the large grayscale glaze blank are all ≤0.5%;

[0060] The body layers of the small gray glaze blank, the medium gray glaze blank, and the large gray glaze blank are all pressed from low moisture-absorbing powder, and the low moisture-absorbing powder is obtained by a wet powder making process.

[0061] The chemical composition of the low-hygroscopic powder includes Al2O3, CaO, MgO, K2O and Na2O. By mass percentage, the content of Al2O3 in the low-hygroscopic powder is 17.2-18.2%, the total content of CaO, MgO, K2O and Na2O is 5.6-6.6%, the content of CaO is ≥0.8%, the content of MgO is ≥1.8%, the content of K2O is ≥1.5%, and the content of Na2O is ≥1.5%.

[0062] In existing technologies, after the green body softens in the high-temperature section of the kiln, it is prone to deformation due to insufficient skeleton strength under its own weight and the friction of the rollers, thus forming roller marks. This problem is particularly pronounced when producing products with a water absorption rate of <0.1%, as it is necessary to balance maintaining an extremely low water absorption rate with high production efficiency (i.e., a short firing cycle). This can easily lead to over-sintering inside the green body, resulting in softened roller marks on the surface due to over-firing. A common industry solution to this is to reduce the firing speed (i.e., adjust the kiln) to prevent a significant temperature difference between the surface and interior of the green body, thus achieving low water absorption while preventing excessive softening of the surface.

[0063] In a preferred embodiment of this technical solution, in order to meet the market demand for high-value, high-performance ceramic products (specifically referring to green body with a water absorption rate of ≤0.5% and the green body made from wet powder production process), and while adapting to the firing curve of the large-capacity kiln in this solution and having good compatibility with fully polished glaze, this solution optimizes the chemical composition of the green body layer to improve the roller marks caused by excessive softening during high-temperature firing.

[0064] Specifically, this scheme first controls the Al2O3 content in the low hygroscopic powder to 17.2-18.2% to avoid the softening of the green body due to excessively low content, which can cause defects such as roller marks or even brick deformation. At the same time, it can also prevent the green body formula from requiring a high firing temperature due to excessively high content, which would make it impossible to achieve the low-temperature fast firing mechanism required by this scheme.

[0065] Furthermore, in order to adapt to the Al2O3 content in the formula, this scheme also designs the fluxing system of the green body formula as a quaternary system of CaO-MgO-K2O-Na2O. In addition to controlling the total content of fluxing components, the content of individual fluxing components is also controlled separately. By utilizing the gradient fluxing effect brought by the quaternary fluxing system, the product is less likely to experience rapid softening of the liquid phase due to a single flux during high-temperature firing, thus preventing the problem of excessive softening of the green body.

[0066] It should be noted that the water absorption rate of the green body mainly affects the strength of the ceramic product, and the strength of the ceramic product also determines its market positioning. Generally speaking, the lower the water absorption rate, the higher the strength of the ceramic product, making it suitable for the mid-to-high-end market. Furthermore, in the preparation process of ceramic green bodies, the powder preparation process is mainly divided into wet powder preparation and dry powder preparation processes: The wet powder preparation process mainly involves first adding water to the prepared green body raw materials and wet ball milling to form a slurry, and then spray granulating the slurry through a spray tower to produce powder. The resulting powder particles have the characteristics of low hardness, large particle size, and low fine powder content. The dry powder preparation process mainly involves first removing iron and crushing the prepared green body raw materials, and then grinding them through a vertical dry mill to obtain fine powder with the required moisture content. After removing iron and slag from the fine powder, it is then wet-granulated to obtain powder that meets the production particle size requirements. The resulting powder particles have the characteristics of high hardness, small particle size, and high fine powder content. In comparison, although dry milling processes are prone to small pits on the surface of the green body, resulting in poor flatness and a noticeable orange peel effect, and may cause black cores and black spots on the surface of the green body after firing, they are mainly suitable for high-volume markets and engineering orders due to their obvious advantages in energy saving and low cost. On the other hand, although wet milling processes consume more energy, they produce higher quality green bodies, and are therefore mainly suitable for mid-to-high-end markets.

[0067] To further explain, the chemical composition of the low-hygroscopic powder, by mass percentage, includes 66.4–67.5% SiO2, 17.2–18.2% Al2O3, 1.6–2.7% Fe2O3, 0.3–0.5% TiO2, 0.8–1.2% CaO, 1.8–2.3% MgO, 1.5–1.6% K2O, 1.5–1.8% Na2O, and 4.8–5.5% loss on ignition.

[0068] Furthermore, to ensure the stability of the green body's performance throughout the forming, drying, and firing processes, while meeting the performance requirements of this invention, this solution proposes a specific embodiment of the chemical composition of the low-hygroscopic powder. In one specific embodiment, this solution also controls the loss on ignition (IL) of the low-hygroscopic powder formulation to below 5.5% to reduce gaseous products generated in the green body, further ensuring the quality of the green body and meeting market demand for high-value, high-performance ceramic products.

[0069] It should be noted that those skilled in the art can configure the chemical composition of the low hygroscopic powder in this scheme according to the local raw material resources. This scheme does not limit the composition and proportion of the raw materials.

[0070] Preferably, the raw materials of the low-hygroscopic powder are composed of bentonite 3%, bauxite 12%, green sand 32%, magnesia 2.5%, broken brick powder 5%, mixed mud 8%, washed mud 4%, edge grinding and polishing mud 7%, talc 1.5% and yellow sand 25% by mass percentage.

[0071] In a preferred embodiment of this technical solution, a specific raw material ratio scheme for low moisture absorption powder is also proposed.

[0072] In this raw material formula, the main role of bentonite is to improve the plasticity and strength of the green body during molding and transportation, and reduce the occurrence of broken bricks.

[0073] The amount of bauxite added to the raw material formula is controlled at 12%. At the same time, mixed clay and washed clay are introduced into the raw material formula to supplement Al2O3 in the chemical composition. Since the main mineral of mixed clay and washed clay is kaolinite, kaolinite is easier to sinter than water-hard / soft borosilicate, thus better matching the low-temperature fast firing mechanism of this scheme.

[0074] Green sand is a type of sand material, mainly produced in Rongchang District and Yongchuan District of Chongqing. It is a unique ceramic raw material in the area. This type of raw material has good firing plasticity and large reserves, making it easy to obtain. If it is added in large quantities to the body formula, the cost of raw materials can be greatly reduced. At the same time, because the chemical composition of green sand also contains a certain amount of MgO, K2O and Na2O, it has a good fluxing effect.

[0075] Magnesia clay, as the main source of MgO in chemical composition, has the effects of fluxing and whitening to a certain extent; in addition, talc, as a supplementary source of MgO in chemical composition, can increase the stability of the formula when the two are combined.

[0076] Yellow sand is also a cheap and white raw material in Chongqing, which has good economic benefits. However, because the Al2O3 content in the raw material is extremely low, excessive use will lead to a decrease in the overall Al2O3 content of the formula, resulting in softening of the green body.

[0077] Broken brick powder is clinker formed by crushing substandard waste products after firing. When added to other raw materials, it can promote rapid firing of the green body layer, further reducing the energy consumption of green body production, thus effectively promoting rapid firing of the green body and shortening the firing cycle. At the same time, replacing traditional feldspar materials as a fluxing agent in the formula has a significant fluxing effect and can also effectively reduce raw material costs.

[0078] Edge grinding and polishing putty is a common waste material in the building ceramics industry. It mainly consists of waste residue generated during the edge grinding and polishing process of ceramic tiles. Its main minerals are glass phase, quartz, and mullite, with small amounts of silicon carbide and grinding resin, making it prone to foaming. As a solid waste material, its outsourced disposal is costly, so it is generally used in small quantities in the body formulation to reduce costs. However, its use in low-water-absorption bodies (water absorption ≤ 0.5%) must be strictly controlled. This is because low-water-absorption bodies produce a large amount of liquid phase during high-temperature firing (used to support the body's density). This liquid phase affects the degassing of easily foaming materials such as silicon carbide and resin in the edge grinding and polishing putty, thus impacting the glaze quality of ceramic tile products using such bodies.

[0079] To further clarify, the dimensions of the body layer of the small gray glaze blank, the body layer of the medium gray glaze blank, and the body layer of the large gray glaze blank are all 800mm×800mm. In the high-capacity kiln, the front edge of all body layers along the conveying direction forms an angle 1 with the width direction of the high-capacity kiln, and the angle of the angle 1 is 5 to 11°.

[0080] To further clarify, the dimensions of the body layer of the small gray glaze blank, the body layer of the medium gray glaze blank, and the body layer of the large gray glaze blank are all 750mm×1500mm. In the high-capacity kiln, the short edge of all body layers forms an angle II with the width direction of the high-capacity kiln, and the angle of the angle II is 7 to 13°.

[0081] like Figure 1 As shown in ∠A, this is a schematic diagram illustrating the angle formed by the width of the 800mm (800mm x 800mm) ceramic tile product and the high-capacity kiln in this design. Figure 2 As shown in ∠B, this diagram illustrates the angle formed between the 715-size (i.e., 750mm×1500mm) ceramic tile product and the width direction of the high-capacity kiln in this scheme. That is, the angle formed between the short side of the body layer (the edge where 750mm is located) and the width direction of the high-capacity kiln.

[0082] In the co-firing process of this scheme, the green body layer is placed on the rollers at a certain small angle before entering the kiln, which can significantly improve the roller mark defects that appear after firing. The core principle is to change the contact state and stress mode between the green body layer and the rollers, thereby reducing the local deformation and stress concentration of the brick blank in the high-temperature plastic stage. The specific reasons are as follows:

[0083] First, when the billet layer is laid flat, the rollers apply force at the edge of the billet layer, which is equivalent to the fulcrum being at the center of the billet layer. The edge is prone to bending and deformation under stress. However, when the billet layer is laid at an angle, the edge of the billet layer is closer to the support point of the rollers, the lever arm is shorter, and the deformation is naturally reduced.

[0084] Secondly, when the billet layer is laid flat, only two narrow edges of the rollers are in contact, and the pressure is easily concentrated; while when it is laid at an angle, the contact line becomes longer, and the pressure per unit area is dispersed.

[0085] Secondly, when the billet layer is laid flat, the shrinkage of the billet layer is subject to the frictional resistance of the rollers, and inward pulling stress is formed on both sides, which easily forms marks on the edges. However, when it is laid at an angle, the direction of frictional force changes, and it is decomposed into axial and transverse components. The transverse component decreases, and the longitudinal shrinkage is more free.

[0086] To further clarify, the coefficient of thermal expansion of the aforementioned medium-expansion glaze is (7.3~7.5)×10. -6 / ℃, according to the mass fraction, the raw materials of the medium-expansion glaze include 38-42 parts of sodium feldspar, 9-11 parts of kaolin, 4-6 parts of quartz, 9-11 parts of nepheline, 12-16 parts of alumina, 10-14 parts of potassium feldspar, 5-7 parts of calcined clay, 2-4 parts of calcined talc, and 10-14 parts of zirconium silicate.

[0087] The coefficient of thermal expansion of the high-expansion glaze is (7.9~8.1)×10. -6 / ℃, according to the mass fraction, the raw materials of the high-expansion glaze include 36-40 parts of albite, 9-11 parts of kaolin, 19-22 parts of quartz, 14-16 parts of nepheline, 14-16 parts of alumina, 1-3 parts of calcined talc and 10-14 parts of zirconium silicate.

[0088] To simplify the formulation process of glazes with different coefficients of expansion, this solution also optimizes the raw material ratio of the glaze. With minimal changes in the types of raw materials, it is only necessary to simply adjust the ratio of the raw materials to obtain glazes with different coefficients of expansion required for production, thereby improving the production efficiency of ceramic tile products.

[0089] Preferably, the raw materials of the medium-expansion glaze, according to the mass fractions, include 40 parts of sodium feldspar, 10 parts of kaolin, 5 parts of quartz, 10 parts of nepheline, 14 parts of alumina, 12 parts of potassium feldspar, 6 parts of calcined clay, 3 parts of calcined talc, and 12 parts of zirconium silicate.

[0090] According to the mass fractions, the raw materials of the high-expansion glaze include 38 parts of albite, 10 parts of kaolin, 20 parts of quartz, 15 parts of nepheline, 15 parts of alumina, 2 parts of calcined talc, and 12 parts of zirconium silicate.

[0091] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0092] Example

[0093] A. Preparation of small grayscale glaze blanks, medium grayscale glaze blanks, and large grayscale glaze blanks;

[0094] B. Small gray glaze blanks, medium gray glaze blanks and large gray glaze blanks are placed sequentially in three brick feeding positions in the same width direction in a high-capacity kiln. A small gray glaze blank, a medium gray glaze blank and a large gray glaze blank in the same width direction constitute a firing unit. There are a total of 100 firing units. The angle formed between the front edge of all glaze blanks along the conveying direction and the width direction of the high-capacity kiln is 9°.

[0095] Firing is carried out at a firing temperature of ≤1100℃ and a firing cycle of ≤30min.

[0096] in,

[0097] In step A, the small gray glaze blank includes a blank body layer, and medium-expansion glaze, colored ink and fully polished glaze applied sequentially from bottom to top on the top surface of the blank body layer;

[0098] In the aforementioned low-grayscale glaze blank, the coefficient of thermal expansion of the medium-expansion glaze is 7.4 × 10⁻⁶. -6 The temperature is / ℃, and according to the mass fraction, the raw materials of the medium-expansion glaze include 40 parts of sodium feldspar, 10 parts of kaolin, 5 parts of quartz, 10 parts of nepheline, 14 parts of alumina, 12 parts of potassium feldspar, 6 parts of calcined clay, 3 parts of calcined talc, and 12 parts of zirconium silicate. The glaze application rate of the medium-expansion glaze is 445 g / m³. 2 .

[0099] In the small grayscale glaze blank, the inkjet volume of the colored ink is 4.0 g / m³. 2 .

[0100] The medium gray glaze blank includes a blank layer, and a high-expansion surface glaze, colored ink and fully polished glaze applied sequentially from bottom to top on the top surface of the blank layer;

[0101] In the medium-gray glaze blank, the coefficient of thermal expansion of the high-expansion surface glaze is 8.0 × 10⁻⁶. -6 The high-expansion glaze, by mass fraction, comprises 38 parts albite, 10 parts kaolin, 20 parts quartz, 15 parts nepheline, 15 parts alumina, 2 parts calcined talc, and 12 parts zirconium silicate. The application rate of the high-expansion glaze is 360 g / m³. 2 .

[0102] In the medium-gray glaze blank, the inkjet volume of the colored ink is 7.0 g / m³. 2 .

[0103] The large gray glaze blank includes a blank body layer, and a high-expansion surface glaze, colored ink and fully polished glaze applied sequentially from bottom to top on the top surface of the blank body layer;

[0104] In the aforementioned high-gray-density glaze blank, the coefficient of thermal expansion of the high-expansion surface glaze is 8.0 × 10⁻⁶.-6 The high-expansion glaze, by weight, comprises 38 parts albite, 10 parts kaolin, 20 parts quartz, 15 parts nepheline, 15 parts alumina, 2 parts calcined talc, and 12 parts zirconium silicate. The application rate of the high-expansion glaze is 445 g / m³. 2 .

[0105] In the aforementioned high-grayscale glaze blank, the inkjet volume of the colored ink is 12.0 g / m³. 2 .

[0106] The body layers of the small grayscale glaze blank, the medium grayscale glaze blank, and the large grayscale glaze blank are all pressed from low-hygroscopic powder, which is obtained by a wet powder-making process. By mass percentage, the raw materials of the low-hygroscopic powder consist of 3% bentonite, 12% bauxite, 32% green sand, 2.5% magnesia, 5% broken brick powder, 8% mixed mud, 4% washed mud, 7% edge-grinding and polishing mud, 1.5% talc, and 25% yellow sand. By mass percentage, the chemical composition of the low-hygroscopic powder obtained from the above-mentioned raw materials includes 66.77% SiO2, 17.71% Al2O3, 1.85% Fe2O3, 0.35% TiO2, 0.92% CaO, 2.16% MgO, 1.56% K2O, 1.67% Na2O, and 4.98% loss on ignition. The remaining content represents unavoidable impurities in the formulation system. The blank layers of the small grayscale glaze blank, the medium grayscale glaze blank, and the large grayscale glaze blank all have a size of 750mm × 1500mm and a thickness of 9mm, with the 750mm edge being the front edge.

[0107] It should be noted that the chemical compositions of the raw materials for the above-mentioned low-hygroscopic powder are as follows:

[0108] The chemical composition of the bauxite, by mass percentage, includes 41.64% SiO2, 40.99% Al2O3, 1.59% Fe2O3, 1.08% TiO2, 0.29% CaO, 0.38% MgO, 0.65% K2O, 0.31% Na2O, and 12.89% loss on ignition.

[0109] The chemical composition of the bentonite, by mass percentage, includes 68.45% SiO2, 14.57% Al2O3, 0.81% Fe2O3, 0.11% TiO2, 1.48% CaO, 1.59% MgO, 2.91% K2O, 1.67% Na2O, and 7.02% loss on ignition.

[0110] According to mass percentage, the chemical composition of the green sand includes 69.51% SiO2, 14.73% Al2O3, 3.19% Fe2O3, 0.31% TiO2, 1.41% CaO, 1.83% MgO, 1.74% K2O, 3.87% Na2O and 2.59% loss on ignition.

[0111] The chemical composition of the magnesian clay, by mass percentage, includes 62.59% SiO2, 5.79% Al2O3, 1.62% Fe2O3, 0.13% TiO2, 0.79% CaO, 1.41% MgO, 0.25% K2O, 0.25% Na2O, and 6.04% loss on ignition.

[0112] The chemical composition of the broken brick powder, by mass percentage, includes 65.67% SiO2, 18.0% Al2O3, 1.75% Fe2O3, 0.5% TiO2, 0.62% CaO, 1.77% MgO, 1.92% K2O, and 2.09% Na2O.

[0113] The chemical composition of the mixed mud, by mass percentage, includes 69.35% SiO2, 20.5% Al2O3, 0.94% Fe2O3, 0.43% TiO2, 0.98% CaO, 0.3% MgO, 1.06% K2O, 0.17% Na2O, and 7.21% loss on ignition.

[0114] The chemical composition of the washed mud, by mass percentage, includes 49.1% SiO2, 33.74% Al2O3, 2.11% Fe2O3, 0.2% TiO2, 0.23% CaO, 0.58% MgO, 2.56% K2O, 0.31% Na2O, and 11.09% loss on ignition.

[0115] The chemical composition of the edge polishing putty, by mass percentage, includes 67.48% SiO2, 18.0% Al2O3, 1.6% Fe2O3, 0.38% TiO2, 2.12% CaO, 2.46% MgO, 2.05% K2O, 2.14% Na2O, and 1.77% loss on ignition.

[0116] The chemical composition of the talc, by mass percentage, includes 32.24% SiO2, 0.69% Al2O3, 0.22% Fe2O3, 0.03% TiO2, 1.76% CaO, 37.57% MgO, 0.01% K2O, 0.09% Na2O, and 27.0% loss on ignition.

[0117] The chemical composition of the yellow sand, by mass percentage, includes 79.63% SiO2, 9.53% Al2O3, 0.65% Fe2O3, 0.22% TiO2, 0.24% CaO, 0.32% MgO, 1.63% K2O, 0.22% Na2O, and 2.8% loss on ignition.

[0118] The fully polished glazes for the small-gray-scale glaze blanks, the medium-gray-scale glaze blanks, and the large-gray-scale glaze blanks are the same. The raw materials for the fully polished glaze consist of albite, kaolin, calcined clay, dolomite, quartz, calcite, alumina, zinc oxide, and strontium carbonate. The fully polished glaze is obtained through a rational configuration of these raw materials. By mass percentage, the chemical composition of the fully polished glaze includes SiO2 47.05%, Al2O3 15.14%, Fe2O3 0.17%, TiO2 0.08%, CaO 8.76%, MgO 3.08%, K2O 0.17%, Na2O 4.7%, ZnO 3.96%, SrO 3.86%, and a loss on ignition of 10.67%. The remaining content represents unavoidable impurities in the formulation system. The glaze application rate for the fully polished glaze is 445 g / m². 2 .

[0119] In step B, the firing curve of the high-capacity kiln includes a preheating section, a preheating section, a medium-temperature section, a high-temperature section, a rapid cooling section, and a slow cooling section: In the preheating section, the surface temperature rises from room temperature to 950°C, and the bottom temperature rises from room temperature to 1100°C, taking 3.57 minutes; in the preheating section, the surface temperature rises from 950°C to 1110°C, and the bottom temperature drops from 1100°C to 1060°C, taking 2.17 minutes; in the medium-temperature section, the surface temperature rises from 1110°C to 1203°C. The temperature rises from 1060℃ to 1226℃ in 7.75 minutes; the surface temperature of the high-temperature section is maintained at 1203℃ and the bottom temperature at 1226℃ for 4.5 minutes; the surface temperature of the rapid cooling section drops from 1203℃ to 570℃ and the bottom temperature drops from 1226℃ to 300℃ for 4.82 minutes; the surface temperature of the slow cooling section drops from 570℃ to room temperature and the bottom temperature drops from 300℃ to room temperature for 6.54 minutes.

[0120] After firing in step B, 10 firing units were randomly selected from 100 firing units. The fired products from these 10 units were then subjected to performance tests according to the test methods of the People's Republic of China National Standards GB / T 4100-2015 and GB / T 45817-2025. The results are shown in Table 1 below.

[0121] Table 1 Performance test results of each fired product in the examples

[0122]

[0123] As shown in Table 1, the performance test results indicate that this solution can achieve low-temperature rapid firing of fully polished glazed ceramic tiles with different ash levels in the same kiln. The fired ceramic tile products not only meet the physical and chemical properties of fully polished glaze, but also balance the tile shape of fully polished glazed ceramic tile products corresponding to different ash levels. The performance test results of roller printing meet the standard of GB / T 45817—2025, and the other performance test results meet the standard of GB / T 4100-2015.

[0124] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A process for the mixed firing of multi-veining effect glazed tiles, characterized in that, The mixed firing process is suitable for a large-capacity kiln, and the large-capacity kiln is provided with three brick feeding positions in the width direction, and the mixed firing process comprises the following steps: A. A plurality of glaze blanks are prepared, and the glaze blanks include small-grayscale glaze blanks, medium-grayscale glaze blanks and large-grayscale glaze blanks; B. The plurality of glaze blanks are sequentially conveyed to the brick feeding positions of the large-capacity kiln, and are fired under the condition that the firing temperature is less than or equal to 1100 DEG C and the firing period is less than or equal to 30 min; In step A, the small gray glaze body comprises a body layer, and a medium-bulging glaze, color ink and full polishing glaze are sequentially applied from bottom to top on the top surface of the body layer; wherein the inkjet amount of the color ink is <4.8g / m 2 ; the glazing amount of the medium-bulging glaze is 420-480g / m 2 . The middle gray glaze blank comprises a blank body layer, and a high-bulging glaze, color ink and full polishing glaze which are sequentially applied from bottom to top on the top surface of the blank body layer; wherein the inkjet amount of the color ink is 4.8-9.6 g / m 2 ; the glazing amount of the high-bulging glaze is 330-390 g / m 2 . The large gray glaze biscuit comprises a biscuit layer, and a high-bulging glaze, color ink and full-polishing glaze which are sequentially applied from bottom to top on the top surface of the biscuit layer; wherein the inkjet amount of the color ink is >9.6 g / m 2 and ≤14.4 g / m 2 ; the glazing amount of the high-bulging glaze is 420-480 g / m 2 . The body layer of the small-grayscale glaze blank, the body layer of the medium-grayscale glaze blank and the body layer of the large-grayscale glaze blank are all pressed from low-hygroscopic powder, and the low-hygroscopic powder is prepared by a wet powder preparation process; The chemical composition of the low-hygroscopic powder includes Al2O3, CaO, MgO, K2O and Na2O, and according to the mass percentage, the content of Al2O3 in the low-hygroscopic powder is 17.2-18.2%, the total content of CaO, MgO, K2O and Na2O is 5.6-6.6%, the content of CaO is greater than or equal to 0.8%, the content of MgO is greater than or equal to 1.8%, the content of K2O is greater than or equal to 1.5%, and the content of Na2O is greater than or equal to 1.5%; The expansion coefficient of the medium bulging enamel is (7.3-7.5) x 10 -6 / ℃, and the expansion coefficient of the high bulging enamel is (7.9-8.1) x 10 -6 / ℃. In step B, the firing curve of the large-capacity kiln includes a preheating section, a preheating section, a medium temperature section, a high temperature section, a rapid cooling section and a slow cooling section: the surface temperature of the preheating section rises from room temperature to 950 DEG C, the bottom temperature rises from room temperature to 1100 DEG C, and the time consumption is 3.5-3.7 min; the surface temperature of the preheating section rises from 950 DEG C to 1110 DEG C, the bottom temperature drops from 1100 DEG C to 1060 DEG C, and the time consumption is 2-2.2 min; the surface temperature of the medium temperature section rises from 1110 DEG C to 1203 DEG C, the bottom temperature rises from 1060 DEG C to 1226 DEG C, and the time consumption is 7.7-7.9 min; the surface temperature of the high temperature section is 1203 DEG C, and the bottom temperature is 1226 DEG C, and the time consumption is 4.3-4.5 min; the surface temperature of the rapid cooling section drops from 1203 DEG C to 570 DEG C, the bottom temperature drops from 1226 DEG C to 300 DEG C, and the time consumption is 4.7-4.9 min; the surface temperature of the slow cooling section drops from 570 DEG C to room temperature, and the bottom temperature drops from 300 DEG C to room temperature, and the time consumption is 6.4-6.6 min; The firing temperature is measured by a British Porsol temperature ring, which reflects the equivalent temperature corresponding to the comprehensive thermal effect experienced by the placement position of the temperature ring during the actual firing process.

2. A multi-veining effect glazed tile mixed firing process according to claim 1, characterized in that, The full polishing glaze of the small-grayscale glaze blank, the full polishing glaze of the medium-grayscale glaze blank and the full polishing glaze of the large-grayscale glaze blank are the same; The raw materials of the full polishing glaze are composed of sodium feldspar, kaolin, burned soil, dolomite, quartz, calcite, alumina, zinc oxide and strontium carbonate; The silicon-aluminum ratio of the full polishing glaze is 3.0-3.2, and according to the mass percentage, the content of Na2O in the full polishing glaze is 4.2-5.2%, and the content of SrO is 3.3-4.3%.

3. A multi-deep effect glazed tile mixed firing process according to claim 2, characterized in that, The chemical composition of the full polishing glaze includes, in percentage by mass, SiO245.0-49.0%, Al2O314.7-15.6%, Fe2O30.1-0.2%, TiO20.05-0.1%, CaO 8.5-9.5%, MgO 2.5-3.5%, K2O 0.1-0.3%, Na2O 4.2-5.2%, ZnO 3.4-4.4%, SrO 3.3-4.3%, and loss on ignition 8.0-12.0%.

4. A multi-deep effect glazed tile mixed firing process according to claim 3, characterized in that, The raw materials of the full polishing glaze are composed of, in percentage by mass, albite 52.5%, kaolin 6%, burned soil 6%, dolomite 15%, quartz 2%, calcite 7%, aluminum oxide 2%, zinc oxide 4%, and strontium carbonate 5.5%.

5. A multi-veining effect glazed tile mixed firing process according to claim 1, characterized in that, The full polishing enamel application amount is 420-480 g / m 2 .

6. A multi-veining effect glazed tile firing process according to claim 1, characterized in that, After the firing of step B, the water absorption of the body layer of the small-grayscale glaze blank, the body layer of the medium-grayscale glaze blank, and the body layer of the large-grayscale glaze blank is all ≤0.5%, in percentage by mass.

7. A multi-deep effect glazed tile mixed firing process according to claim 6, characterized in that, The chemical composition of the low-hygroscopicity powder includes, in percentage by mass, SiO266.4-67.5%, Al2O317.2-18.2%, Fe2O31.6-2.7%, TiO20.3-0.5%, CaO 0.8-1.2%, MgO 1.8-2.3%, K2O 1.5-1.6%, Na2O 1.5-1.8%, and loss on ignition 4.8-5.5%.

8. A multi-deep effect glazed tile mixed firing process according to claim 6, characterized in that, The size of the body layer of the small-grayscale glaze blank, the body layer of the medium-grayscale glaze blank, and the body layer of the large-grayscale glaze blank is all 800mm×800mm, and in the large-capacity kiln, the front side edge of all the body layers along the conveying direction forms an angle one with the width direction of the large-capacity kiln, and the angle of the angle one is 5-11°.

9. A multi-deep effect glazed tile mixed firing process according to claim 6, characterized in that, The size of the body layer of the small-grayscale glaze blank, the body layer of the medium-grayscale glaze blank, and the body layer of the large-grayscale glaze blank is all 750mm×1500mm, and in the large-capacity kiln, the short side edge of all the body layers forms an angle two with the width direction of the large-capacity kiln, and the angle of the angle two is 7-13°.

10. A multi-deep effect glazed tile firing process according to claim 1, characterized in that, The raw materials of the medium-swelling glaze include, in parts by mass, albite 38-42, kaolin 9-11, quartz 4-6, nepheline 9-11, aluminum oxide 12-16, potassium feldspar 10-14, burned soil 5-7, burned talc 2-4, and zirconium silicate 10-14. The raw materials of the high-swelling glaze include, in parts by mass, albite 36-40, kaolin 9-11, quartz 19-22, nepheline 14-16, aluminum oxide 14-16, burned talc 1-3, and zirconium silicate 10-14.

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