Preparation method of super-white ceramic white brick

Abstract

The application relates to the technical field of ceramic materials, in particular to a preparation method of super-white ceramic white bricks, which comprises the following steps: mixing high-purity quartz powder, calcined kaolin, calcium carbonate and low-radioactivity alumina powder to obtain base body raw materials, adding a dispersing aid and a binder to granulate and then to press-forming, and then performing first-time firing, glaze layer coating and second-time firing to obtain the super-white ceramic white bricks. According to the application, the raw material ratio and the process flow are optimized, the radioactivity risk is reduced while the high whiteness is ensured, the production steps are simplified, the product consistency is improved, the whiteness, the environmental protection performance and the decoration effect are excellent, and the application is suitable for high-end building decoration and art product manufacturing fields.

Description

Technical Field

[0001] This application relates to the field of ceramic materials technology, and in particular to a method for preparing ultra-white ceramic bricks. Background Technology

[0002] With the continuous development and innovation of building ceramic materials technology, ultra-white ceramic white bricks have become the mainstream choice in the high-end building materials market due to their excellent whiteness, extremely low radioactivity index and excellent decorative performance.

[0003] Currently, the research and development of ultra-white ceramic tiles mainly focuses on raw material selection and proportioning, process optimization and innovation, and comprehensive performance improvement. In terms of raw materials, ultra-white ceramic tiles typically use low-iron raw materials such as high-purity quartz, feldspar, and kaolin. Through fine processing and flotation technology, the content of coloring oxides such as iron and titanium is reduced to ensure the whiteness of the body. Meanwhile, adding various whitening agents has become a common practice in the industry. These include traditional metal oxides such as zinc oxide and zirconium oxide, as well as highly efficient but costly whitening components such as rare earth elements (e.g., cerium oxide and yttrium oxide). Through their scattering and regulating effects on light, they effectively improve the visual whiteness of the body. In terms of production processes, key technologies such as high-temperature sintering (usually above 1200℃), precise oxidizing atmosphere control, and rapid cooling are widely adopted. High-temperature sintering helps promote the densification process of the body, reduces open pores, and improves mechanical strength; the oxidizing atmosphere ensures that the iron element in the raw materials is reduced to a lower concentration. The form exists to avoid generating more powerful coloring capabilities. This process reduces yellowing; rapid cooling helps suppress excessive grain growth during production, maintaining the fine structure and high whiteness of the ceramic body. Furthermore, current research focuses on the overall performance of the product, including practical indicators such as flexural strength, abrasion resistance, and stain resistance. Through microstructure control (such as crystal phase design) and the use of composite additives, the overall quality of ultra-white ceramic tiles is further optimized.

[0004] Despite significant progress in the research of ultra-white ceramic tiles, numerous challenges remain in their actual industrialization. First, existing production processes are often complex. For example, achieving high whiteness requires multiple additions, special pretreatment, or multi-stage firing processes, which not only increases energy and time costs but also demands greater consistency in process control. Second, some whitening raw materials (such as certain zircon sands or rare earth minerals) may introduce naturally occurring radioactive nuclides, posing a risk of exceeding radioactivity levels in the product, contradicting the concept of green and environmentally friendly building. Furthermore, ensuring batch-to-batch stability of product performance while maintaining high-efficiency production remains a technical challenge for many companies. Product quality is particularly susceptible to fluctuations due to raw material variations and minor adjustments to process parameters.

[0005] Therefore, in response to the above-mentioned industry pain points, this invention provides a novel method for preparing ultra-white ceramic tiles. The aim is to significantly reduce the radioactivity risk of the product while ensuring extremely high whiteness of the body by systematically optimizing the raw material formula structure and process flow, simplifying key production steps, and enhancing process controllability and product consistency, thereby meeting the growing market demand for high-performance, environmentally friendly, and cost-controllable ultra-white ceramic tiles. Summary of the Invention

[0006] This invention provides a method for preparing ultra-white ceramic bricks, which aims to reduce radioactivity risks while ensuring high whiteness, simplify production steps, and improve product consistency by optimizing raw material formulation and process flow.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] Step 1: Mix high-purity quartz powder, calcined kaolin, calcium carbonate, and low-radioactivity alumina powder in a certain proportion to obtain the basic raw material; the weight parts of the high-purity quartz powder are 35-45 parts, the weight parts of the calcined kaolin are 20-30 parts, the weight parts of the calcium carbonate are 10-15 parts, and the weight parts of the low-radioactivity alumina powder are 15-25 parts.

[0009] Step 2: The basic billet raw material is fed into a high-efficiency ball mill for ball milling, and then subjected to sieving and iron removal to obtain the basic billet slurry;

[0010] Step 3: The basic green body slurry is injected into a mixing tank, a dispersant and a binder are added, and after being stirred evenly, it is pumped into a spray drying tower for granulation to obtain green body particles; the dispersant is sodium polyacrylate, which is 0.1-0.3 parts by weight; the binder is sodium carboxymethyl cellulose, which is 0.2-0.4 parts by weight.

[0011] Step 4: Press the green body particles into shape, dry them until the moisture content is less than 1%, and then gradually heat them to 1100-1300℃ for the first firing to obtain a pre-fired green body;

[0012] Step 5: Mix nano-sized titanium dioxide with silica sol and coat it onto the surface of the pre-fired body to form a glaze layer; the nano-sized titanium dioxide is 60-70 parts by weight and the silica sol is 30-40 parts by weight.

[0013] Step 6: The pre-fired body coated with glaze is heated to 1200-1400℃ for a second firing, and after cooling, the ultra-white ceramic brick is obtained.

[0014] Furthermore, in step one, the silica content of the high-purity quartz powder is not less than 99.5%;

[0015] The alumina content of the calcined kaolin is not less than 40%;

[0016] The purity of the calcium carbonate is not less than 98%;

[0017] The specific activity of the low-radioactivity alumina powder does not exceed 1 Bq / kg.

[0018] Furthermore, in step two, the ball milling time is 5 hours;

[0019] The sieve is 200 mesh;

[0020] The iron removal process uses a high-gradient magnetic separator.

[0021] The particle size distribution of the basic preform slurry is in the range of 50-150 μm.

[0022] Furthermore, in step three, the dispersing agent and the binder are added in the following order: first add the dispersing agent and stir for 10 minutes, then add the binder and continue stirring for 10 minutes.

[0023] The stirring tank rotates at 500-800 rpm.

[0024] Furthermore, in step three, the inlet temperature of the spray drying tower is 300°C, the outlet temperature is 120°C, and the drying time is 1 minute.

[0025] Furthermore, in step four, the pressure for pressing the blank particles is 25 MPa;

[0026] The drying temperature is 110℃ and the drying time is 8 hours.

[0027] Furthermore, in step four, the gradient temperature increase includes first increasing the temperature from room temperature to 600°C at a rate of 10°C / min, then increasing it to 1000°C at a rate of 5°C / min, and finally increasing it to 1200°C at a rate of 10°C / min, and maintaining it at 1200°C for 1 hour.

[0028] Furthermore, in step five, the particle size of the nano-sized titanium dioxide is 20-50 nm;

[0029] The silica sol has a silica content of 30-40%.

[0030] Furthermore, in step five, the coating thickness of the glaze layer is 0.4 mm, and the coating process is achieved by dip coating.

[0031] Furthermore, in step six, the gradient temperature increase includes first raising the temperature from room temperature to 900°C at a rate of 15°C / min, during which oxygen is continuously introduced, then stopping the oxygen introduction, and raising the temperature to 1300°C at a rate of 10°C / min, and maintaining the temperature at 1300°C for 1.5 hours.

[0032] The cooling rate is controlled at 3℃ / min, and the product is discharged from the kiln at a temperature below 50℃ to obtain the final product.

[0033] The beneficial effects of the technical solution provided by this invention include at least the following:

[0034] This invention uses high-purity quartz powder and low-radioactivity alumina powder as the main raw materials, combined with a specific ratio of calcined kaolin and calcium carbonate. Through the synergistic effect of dispersants and binders, it can effectively reduce the porosity of the green body during the firing process, while reducing radioactivity problems caused by the introduction of impurities.

[0035] This invention uses nano-sized titanium dioxide and silica sol as a glaze combination, which can form a dense and uniform glaze structure during high-temperature firing, thereby improving whiteness and maintaining good decorative properties.

[0036] The optimized two-step firing process and precise temperature control of this invention not only ensure a high degree of consistency in product quality between batches, but also simplify the production process and improve process controllability. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 The whiteness test results are for the examples and comparative examples;

[0039] Figure 2 The results of specific activity tests for radioactivity in the examples and comparative examples;

[0040] Figure 3 The results of water absorption tests are for the examples and comparative examples;

[0041] Figure 4 The flexural strength test results are for the examples and comparative examples;

[0042] Figure 5 The results of glaze hardness tests are shown for the examples and comparative examples. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0044] The present invention provides a method for preparing ultra-white ceramic white bricks, which includes the following raw materials: high-purity quartz powder, calcined kaolin, calcium carbonate, low-radioactivity alumina powder, sodium polyacrylate, sodium carboxymethyl cellulose, nano-sized titanium dioxide, and silica sol.

[0045] Here, 16 examples are compared with 6 comparative examples.

[0046] On the one hand, the proportions of each raw material and the firing conditions in Examples 1-16 of the present invention are shown in the table below.

[0047]

[0048] Example 1: High-purity quartz powder, calcined kaolin, calcium carbonate, and low-radioactivity alumina powder were mixed in weight ratios of 45 parts, 30 parts, 10 parts, and 15 parts, respectively, and uniformly mixed for 10 minutes using a dry mixer to obtain the basic green body raw material. The high-purity quartz powder had a silica content of 99.6%, the calcined kaolin had an alumina content of 42%, the calcium carbonate had a purity of 98.5%, and the low-radioactivity alumina powder had a specific activity of 0.8 Bq / kg.

[0049] The basic green body raw material is put into a high-efficiency ball mill, an appropriate amount of water is added (solid content is controlled at 65 parts), and the ball mill is milled for 5 hours. After that, it is sieved through a 200-mesh sieve and then treated by a high gradient magnetic separator to remove iron, so as to obtain a basic green body slurry with a particle size distribution of 50-150 μm.

[0050] The basic green body slurry was injected into a mixing tank with a rotation speed of 800 rpm. First, 0.1 parts of sodium polyacrylate were added and stirred for 10 minutes. Then, 0.4 parts of sodium carboxymethyl cellulose were added and stirred for another 10 minutes. After that, it was pumped into a spray drying tower with an inlet temperature of 300℃, an outlet temperature of 120℃, and a drying time of 1 minute to obtain green body particles.

[0051] The green body particles were pressed into shape under a pressure of 25 MPa, and then placed in a drying oven at 110℃ for 8 hours to reduce the moisture content to less than 1 part. Subsequently, the temperature was increased from room temperature to 600℃ in a kiln at a rate of 10℃ / min, then increased to 1000℃ at a rate of 5℃ / min, and finally increased to 1200℃ at a rate of 10℃ / min. The temperature was held for 1 hour, and after cooling, a pre-fired green body was obtained.

[0052] The nano-sized titanium dioxide and silica sol were mixed in a ratio of 60 parts by weight and 40 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer;

[0053] The glazed body is placed in a kiln, oxygen is introduced, and the temperature is raised from room temperature to 900°C at 15°C / min, then raised to 1300°C at 10°C / min, held for 1.5 hours, and finally cooled slowly to below 50°C at 3°C / min before being removed from the kiln to obtain ultra-white ceramic bricks.

[0054] Example 2: The basic green body slurry was injected into a mixing tank with a rotation speed of 800 rpm. First, 0.3 parts of sodium polyacrylate were added and stirred for 10 min. Then, 0.2 parts of sodium carboxymethyl cellulose were added and stirred for another 10 min. After that, it was pumped into a spray drying tower with an inlet temperature of 300℃, an outlet temperature of 120℃, and a drying time of 1 min to obtain green body particles. The remaining steps were the same as in Example 1.

[0055] Example 3: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 1.

[0056] Example 4: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 2.

[0057] Example 5: The high-purity quartz powder, calcined kaolin, calcium carbonate, and low-radioactivity alumina powder were mixed in weight ratios of 45 parts, 20 parts, 15 parts, and 20 parts, respectively, and uniformly mixed for 10 minutes using a dry mixer to obtain the basic green body raw material. The high-purity quartz powder had a silica content of 99.6%, the calcined kaolin had an alumina content of 42%, the calcium carbonate had a purity of 98.5%, and the low-radioactivity alumina powder had a specific activity of 0.8 Bq / kg. The remaining steps were the same as in Example 1.

[0058] Example 6: The basic green body slurry was injected into a mixing tank with a rotation speed of 800 rpm. First, 0.3 parts of sodium polyacrylate were added and stirred for 10 min. Then, 0.2 parts of sodium carboxymethyl cellulose were added and stirred for another 10 min. After that, it was pumped into a spray drying tower with an inlet temperature of 300℃, an outlet temperature of 120℃, and a drying time of 1 min to obtain green body particles. The remaining steps were the same as in Example 5.

[0059] Example 7: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 5.

[0060] Example 8: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 6.

[0061] Example 9: The high-purity quartz powder, calcined kaolin, calcium carbonate, and low-radioactivity alumina powder were mixed in weight ratios of 45 parts, 20 parts, 10 parts, and 25 parts, respectively, and uniformly mixed for 10 minutes using a dry mixer to obtain the basic green body raw material. The high-purity quartz powder had a silica content of 99.6%, the calcined kaolin had an alumina content of 42%, the calcium carbonate had a purity of 98.5%, and the low-radioactivity alumina powder had a specific activity of 0.8 Bq / kg. The remaining steps were the same as in Example 1.

[0062] Example 10: The basic green body slurry was injected into a mixing tank with a rotation speed of 800 rpm. First, 0.3 parts of sodium polyacrylate were added and stirred for 10 min. Then, 0.2 parts of sodium carboxymethyl cellulose were added and stirred for another 10 min. After that, it was pumped into a spray drying tower with an inlet temperature of 300℃, an outlet temperature of 120℃, and a drying time of 1 min to obtain green body particles. The remaining steps were the same as in Example 9.

[0063] Example 11: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 9.

[0064] Example 12: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 10.

[0065] Example 13: The high-purity quartz powder, calcined kaolin, calcium carbonate, and low-radioactivity alumina powder were mixed in weight ratios of 35 parts, 30 parts, 10 parts, and 25 parts, respectively, and uniformly mixed for 10 minutes using a dry mixer to obtain the basic green body raw material. The high-purity quartz powder had a silica content of 99.6%, the calcined kaolin had an alumina content of 42%, the calcium carbonate had a purity of 98.5%, and the low-radioactivity alumina powder had a specific activity of 0.8 Bq / kg. The remaining steps were the same as in Example 1.

[0066] Example 14: The basic green body slurry was injected into a mixing tank with a rotation speed of 800 rpm. First, 0.3 parts of sodium polyacrylate were added and stirred for 10 min. Then, 0.2 parts of sodium carboxymethyl cellulose were added and stirred for another 10 min. After that, it was pumped into a spray drying tower with an inlet temperature of 300℃, an outlet temperature of 120℃, and a drying time of 1 min to obtain green body particles. The remaining steps were the same as in Example 13.

[0067] Example 15: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 13.

[0068] Example 16: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 70 parts by weight and 30 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 14.

[0069] On the other hand, the proportions of each raw material and the firing conditions of Comparative Examples 1-6 of the present invention are shown in the table below.

[0070]

[0071] Comparative Example 1: Ordinary quartz powder, calcined kaolin, calcium carbonate, and low-radioactivity alumina powder were mixed in weight ratios of 45 parts, 30 parts, 10 parts, and 15 parts, respectively, and uniformly mixed for 10 minutes using a dry mixer to obtain the basic green body raw material. The high-purity quartz powder had a silica content of 98%, the calcined kaolin had an alumina content of 42%, the calcium carbonate had a purity of 98.5%, and the low-radioactivity alumina powder had a radioactivity specific activity of 0.8 Bq / kg; the remaining steps were the same as in Example 1.

[0072] Comparative Example 2: The basic green body slurry was injected into a mixing tank with a rotation speed of 800 rpm, and only 0.5 parts of sodium polyacrylate were added and stirred for 10 minutes. Then it was pumped into a spray drying tower with an inlet temperature of 300℃, an outlet temperature of 120℃, and a drying time of 1 minute to obtain green body particles; the remaining steps were the same as in Example 1.

[0073] Comparative Example 3: The nano-sized titanium dioxide and silica sol were mixed in a ratio of 40 parts by weight and 60 parts by weight, respectively; the mixed glaze was coated onto the surface of the pre-fired body by dip coating, with a coating thickness of 0.4 mm, to form a glaze layer; the remaining steps were the same as in Example 1.

[0074] Comparative Example 4: The glazed body was placed in a kiln, and the temperature was raised from room temperature to 900°C at 15°C / min without oxygen, then raised to 1300°C at 10°C / min, held for 1.5 hours, and finally slowly cooled to below 50°C at 3°C / min before being removed from the kiln; the remaining steps were the same as in Example 1.

[0075] Comparative Example 5: The high-purity quartz powder, calcined kaolin, calcium carbonate, and low-radioactivity alumina powder were mixed in weight ratios of 50 parts, 10 parts, 20 parts, and 20 parts, respectively, and uniformly mixed for 10 minutes using a dry mixer to obtain the basic green body raw material. The high-purity quartz powder had a silica content of 99.6%, the calcined kaolin had an alumina content of 42%, the calcium carbonate had a purity of 98.5%, and the low-radioactivity alumina powder had a specific activity of 0.8 Bq / kg; the remaining steps were the same as in Example 1.

[0076] Comparative Example 6: The high-purity quartz powder, calcined kaolin, calcium carbonate, and industrial alumina powder were mixed in weight ratios of 45 parts, 30 parts, 10 parts, and 15 parts, respectively, and uniformly mixed for 10 minutes using a dry mixer to obtain the basic green body raw material. The high-purity quartz powder had a silica content of 99.6%, the calcined kaolin had an alumina content of 42%, the calcium carbonate had a purity of 98.5%, and the low-radioactivity alumina powder had a specific activity of 0.8 Bq / kg; the remaining steps were the same as in Example 1.

[0077] Performance test results: The ultra-white ceramic tiles obtained in the above examples and comparative examples were subjected to performance tests, and the results are shown in the table below:

[0078]

[0079]

[0080] The ultra-white ceramic bricks prepared in this application exhibit higher whiteness, lower specific radioactivity, and superior physical properties compared to the comparative example. High-purity quartz powder and low-radioactivity alumina powder are used as the main raw materials, combined with a specific ratio of calcined kaolin and calcium carbonate. Through the synergistic effect of dispersants and binders, the porosity of the green body during firing is effectively reduced, while minimizing radioactivity issues caused by impurities. The use of nano-sized titanium dioxide and silica sol as a glaze combination enables the formation of a dense and uniform glaze structure during high-temperature firing, thereby enhancing whiteness and maintaining good decorative properties. Optimized two-step firing and precise temperature control ensure high consistency in product quality between batches while simplifying the production process and improving process controllability.

[0081] In Comparative Example 1, the whiteness of the green body decreased significantly and the radioactivity increased due to the high impurity content of the ordinary quartz powder. In Comparative Example 2, the lack of binder resulted in poor green body strength, which in turn affected the final sintering strength. In Comparative Example 3, the whiteness dropped to 78 degrees due to insufficient covering power of the low-content nano-sized titanium dioxide. In Comparative Example 4, poor glaze development under anaerobic firing prevented the formation of a stable high-whiteness glaze, reducing hardness and wear resistance. In Comparative Example 5, the low calcination level of kaolin and the excessively high purity of quartz powder disrupted the balance of the green body formula, resulting in poor sintering and a significant increase in water absorption. In Comparative Example 6, the direct use of highly radioactive industrial alumina powder resulted in severely excessive radioactivity.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing an ultra-white ceramic white tile, characterized in that, The application relates to a preparation method of an ultra-white ceramic white brick. Step one: high-purity quartz powder, calcined kaolin, calcium carbonate and low-radioactivity alumina powder are mixed according to proportions to obtain base body raw materials; the high-purity quartz powder is 35-45 parts by weight, the calcined kaolin is 20-30 parts by weight, the calcium carbonate is 10-15 parts by weight, and the low-radioactivity alumina powder is 15-25 parts by weight; The silicon dioxide content of the high-purity quartz powder is not less than 99.5%; The specific radioactivity of the low-radioactivity alumina powder is not more than 1 Bq / kg; Step two: the base body raw materials are put into a high-efficiency ball mill for ball milling treatment, and then are subjected to screen mesh treatment and iron removal treatment to obtain base body slurry; Step three: the base body slurry is injected into a stirring barrel, a dispersing aid and a binder are added, and after uniform stirring, the base body slurry is pumped into a spray drying tower for granulation to obtain body particles; the dispersing aid is sodium polyacrylate, and the weight part of the sodium polyacrylate is 0.1-0.3 parts; the binder is sodium carboxymethyl cellulose, and the weight part of the sodium carboxymethyl cellulose is 0.2-0.4 parts; Step four: the body particles are pressed into a shape, dried until the moisture content is less than 1%, and then subjected to first firing at a gradient temperature of 1100-1300 DEG C to obtain pre-fired body; Step five: nano-grade titanium white powder and silica sol are mixed and coated on the surface of the pre-fired body to form a glaze layer; the weight part of the nano-grade titanium white powder is 60-70 parts, and the weight part of the silica sol is 30-40 parts; Step six: the pre-fired body coated with the glaze layer is subjected to second firing at a gradient temperature of 1200-1400 DEG C, and the ultra-white ceramic white brick is obtained after cooling. The gradient temperature rising comprises the following steps: first, rising from room temperature to 900 DEG C at a speed of 15 DEG C / min, in this stage, oxygen is continuously supplied, then the oxygen supply is stopped, and then rising to 1300 DEG C at a speed of 10 DEG C / min, and keeping at 1300 DEG C for 1.5 h; the cooling speed is controlled at 3 DEG C / min, and the final product is obtained when the temperature is below 50 DEG C.

2. The preparation method of the ultra-white ceramic white brick according to claim 1, wherein: the alumina content of the calcined kaolin is not less than 40%; and the purity of the calcium carbonate is not less than 98%.

3. The preparation method of the ultra-white ceramic white brick according to claim 1, wherein: in step two, the ball milling time is 5 h; the screen mesh is 200 meshes; the iron removal treatment device is a high-gradient magnetic separator; and the particle size distribution of the base body slurry is in the range of 50-150 mu m.

4. The preparation method of the ultra-white ceramic white brick according to claim 1, wherein: in step three, the adding sequence of the dispersing aid and the binder is that the dispersing aid is first added and stirred for 10 min, and then the binder is added and stirred for 10 min; and the rotating speed of the stirring barrel is 500-800 rpm.

5. The preparation method of the ultra-white ceramic white brick according to claim 1, wherein: in step three, the inlet temperature of the spray drying tower is 300 DEG C, the outlet temperature is 120 DEG C, and the drying time is 1 min.

6. The preparation method of the ultra-white ceramic white brick according to claim 1, wherein: ​ ​ ​ ​ ​ ​ ​ ​ ​ The pressure of the green body particle compression molding in the step four is 25 PMa; The drying temperature is 110 ℃, and the drying time is 8 h. 7.The method of claim 1, wherein the super-white ceramic white brick is prepared by the steps of: preparing a ceramic body by mixing a ceramic body material with a binder; drying the ceramic body; and sintering the dried ceramic body. The gradient temperature rising in the step four includes first rising from room temperature to 600 ℃ at a rate of 10 ℃ / min, then rising to 1000 ℃ at a rate of 5 ℃ / min, finally rising to 1200 ℃ at a rate of 10 ℃ / min, and keeping at 1200 ℃ for 1 h. 8.The method of claim 1, wherein the super-white ceramic white brick is prepared by the steps of: preparing a ceramic body by mixing a ceramic body material with a binder; drying the ceramic body; and sintering the dried ceramic body. The particle size of the nano-sized titanium white powder in the step five is 20-50 nm. The silica content of the silica sol is 30-40%. 9.The method of claim 1, wherein the super-white ceramic white brick is prepared by the steps of: preparing a ceramic body by mixing a ceramic body material with a binder; drying the ceramic body; and sintering the dried ceramic body. ​

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