Pre-sintered wollastonite tailing ceramic rock plate for concentrating solar furnace and preparation method of pre-sintered wollastonite tailing ceramic rock plate

Abstract

The invention provides a concentrated solar furnace pre-sintered wollastonite tailing ceramic rock plate and a preparation method thereof. The preparation method comprises the following steps: performing crushing and ball milling treatment on wollastonite tailings, putting the wollastonite tailings in a concentrated solar furnace for pre-sintering at the pre-sintering temperature of 700-800 DEG C and the heat preservation time of 10-15 minutes, and cooling to obtain pre-sintered wollastonite tailings; carrying out ball milling treatment to obtain wollastonite powder; mixing and ball-milling with Suzhou kaolin, potassium feldspar, albite, quartz and a light absorbing agent to obtain a blank; performing granulation, aging and compression molding to obtain a green body; the green body is dried and then placed in a concentrating solar furnace to be sintered, the sintering temperature ranges from 920 DEG C to 1000 DEG C, the heat preservation time ranges from 10 min to 15 min, and the ceramic rock plate is obtained after furnace cooling. The solar furnace is used for pre-sintering and activating the wollastonite tailings, then the wollastonite tailings and other raw materials are mixed and sintered, solar energy is used in the whole process, low-temperature rapid sintering is achieved, and it is ensured that the rock plate has high density and high strength.

Description

Technical Field

[0001] This invention relates to the field of building ceramics manufacturing technology, specifically to a ceramic slab made from wollastonite tailings pre-fired in a concentrated solar furnace and its preparation method. Background Technology

[0002] As a high-energy-consuming and high-emission sector, the building ceramics industry faces increasingly urgent needs for production cost control and green transformation. Exploring zero-carbon heating methods, such as concentrated solar power (CSP) furnaces, has become an important direction for the industry to achieve energy conservation, emission reduction, and clean production. At the same time, optimizing the raw material structure is equally crucial. Wollastonite tailings, as an industrial solid waste, has a stable source and low cost, and its mineral composition is suitable for use in ceramic systems. If a method for preparing ceramic slabs can be developed by combining CSP furnaces with wollastonite tailings, it can not only significantly reduce production energy consumption and raw material costs, but also provide a new way to utilize solid waste resources with high added value, which is of great value to the sustainable development of the industry.

[0003] Currently, the firing temperature range of traditional ceramic slabs is between 1000 and 1230℃, the firing cycle is 80 to 180 minutes, and the flexural strength is between 40 and 90 MPa. Chinese invention patent "A Low-Temperature Fast-Firing Ceramic Slab and Its Preparation Method" (CN115010465A) describes the production of ceramic slabs using clay, calcined bauxite, wollastonite, etc., as main raw materials in a roller kiln. The firing temperature is between 1050 and 1100℃, the firing time is 30 to 50 minutes, the water absorption rate is 0.1% to 0.5%, and the strength is >50 MPa. Chinese invention patent CN114163213A, entitled "A Ceramic Slab Prepared by Ultra-Low Temperature Rapid Firing Using Wollastonite Tailings and its Manufacturing Method," describes the production of ceramic slabs using wollastonite tailings and clay as the main components, fired in a roller kiln at a temperature of 1000-1100 ℃ for 35-50 min, with a water absorption rate of 0.08%-2.4% and a modulus of rupture of 43-58 MPa. Chinese invention patent CN114262218A, entitled "A High-Performance Ceramic Slab and its Preparation Method," describes the production of ceramic slabs using washed clay, lithium porcelain stone, and wollastonite as the main components, fired at a temperature of 1190-1230 ℃, with a water absorption rate of 0.39%-0.45% and a flexural strength of 85.23-88.93 MPa. Although the aforementioned invention patents have made some progress in achieving low-temperature rapid firing or utilizing wollastonite tailings, they all rely on traditional kilns and have failed to achieve clean energy. Moreover, in the pursuit of low temperatures, the rock slabs often suffer from insufficient strength or poor density due to impurities in the tailings.

[0004] Therefore, the industry urgently needs a new solution that can collaboratively address energy, raw material, and performance challenges in order to achieve a balance between low-temperature sintering, clean production, and high-performance materials. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a ceramic slab pre-fired from wollastonite tailings in a concentrated solar furnace and its preparation method, aiming to solve the technical problems of high firing temperature, high energy consumption, high raw material cost of existing ceramic slabs, and difficulty in achieving both densification degree and mechanical properties under low temperature firing conditions.

[0006] In a first aspect, the present invention provides a method for preparing ceramic slabs made from pre-fired wollastonite tailings in a concentrating solar furnace, comprising the following steps: S1. The wollastonite tailings are crushed and ball-milled, and then placed in a concentrated solar furnace for pre-firing at a temperature of 700-800℃ for 10-15 minutes. After cooling, the pre-firing wollastonite tailings are obtained. S2. The pre-burned wollastonite tailings are ball-milled to obtain wollastonite powder; the wollastonite powder is mixed with Suzhou kaolin, potassium feldspar, sodium feldspar, quartz and light absorber and then ball-milled to obtain a billet; S3. Granulate, age, and press the billet into shape to obtain a green billet; S4. After drying the green body, place it in a concentrated solar furnace for firing at a sintering temperature of 920~1000℃ and a holding time of 10~15min. After cooling in the furnace, ceramic slabs are obtained.

[0007] In a second aspect, the present invention provides a ceramic slab made from wollastonite tailings pre-fired in a concentrated solar furnace, which is prepared by the preparation method described in the first aspect.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention significantly reduces the firing temperature and greatly improves the mechanical properties. The ceramic slab prepared has a flexural strength of up to 90-100 MPa and a water absorption rate of 0.01%-0.05% at a firing temperature of 920-1000℃. The light absorber and the solar furnace work together to improve the photothermal conversion efficiency of the green body, realize rapid heating and mass transfer, promote the generation of liquid phase at low temperature and fill the pores, and form a dense structure with anorthite as the main crystalline phase and quartz as the secondary crystalline phase, thereby achieving low-temperature high-strength sintering.

[0009] (2) Pre-firing treatment effectively solves the problem of unstable product performance caused by direct utilization of wollastonite tailings. The core of this invention lies in the concentrated solar energy pre-firing treatment of wollastonite tailings. After pre-firing, the main phases of the tailings are wollastonite and quartz, and their microstructure changes from the original needle-like shape to a mesh-like structure, significantly increasing the specific surface area and reactivity. Pre-firing fundamentally ensures the stable performance and high quality of ceramic slabs prepared from wollastonite tailings.

[0010] (3) Achieving green and low-carbon manufacturing from the source of energy and raw materials yields significant economic benefits. This invention uses a concentrated solar furnace as the heat source throughout the entire process, completely replacing traditional gas or electric kilns, thus eliminating fossil fuel consumption and carbon emissions at the source. Simultaneously, this method uses pre-fired wollastonite tailings as the main raw material, significantly reducing raw material costs. The combination of these two factors results in a double reduction in energy and raw material costs, providing a practical and feasible technical path for the green transformation of the building ceramics industry. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a concentrating solar furnace in an embodiment of the present invention; Figure 2 The image shown is the XRD pattern of the ceramic slab obtained in Example 1 of this invention. Figure 3 This is a SEM image of the cross-section of the ceramic slab obtained in Example 1 of the present invention; Figure 4 This is a SEM image of the wollastonite tailings raw material in Example 1 of the present invention; Figure 5 The image shows the XRD pattern of wollastonite tailings pre-calcined in the solar furnace in Embodiment 1 of this invention. Figure 6 This is a SEM image of the wollastonite tailings pre-burned in the solar furnace in Embodiment 1 of the present invention. Detailed Implementation

[0012] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0013] To address the technical problems of high firing temperature, high energy consumption, high raw material cost, and difficulty in achieving both densification and mechanical properties under low-temperature firing conditions in existing ceramic slabs, this invention provides a method for preparing ceramic slabs made from wollastonite tailings pre-fired in a concentrated solar furnace. The method employs a two-step "pre-firing-sintering" process: first, the wollastonite tailings are pre-fired and activated in a concentrated solar furnace; then, they are mixed with other raw materials and finally sintered using solar energy. This process utilizes clean solar energy throughout, achieving rapid low-temperature firing and ensuring the slabs possess high density and high strength.

[0014] In a first aspect, embodiments of the present invention provide a method for preparing ceramic slabs made from pre-fired wollastonite tailings in a concentrating solar furnace, comprising the following steps: S1 crushes and ball-mills the wollastonite tailings, then places them in a concentrated solar furnace for pre-firing at a temperature of 700-800℃ for 10-15 minutes. After cooling, the pre-fired wollastonite tailings are obtained. S2. The pre-burned wollastonite tailings are ball-milled to obtain wollastonite powder; the wollastonite powder is mixed with Suzhou kaolin, potassium feldspar, sodium feldspar, quartz and light absorber and then ball-milled to obtain a billet; S3. Granulate, age, and press the billet into shape to obtain a green billet; S4. After drying the green body, place it in a concentrated solar furnace for firing at a sintering temperature of 920~1000℃ and a holding time of 10~15min. After cooling in the furnace, ceramic slabs are obtained.

[0015] In the technical solution of this invention embodiment, the wollastonite tailings are first subjected to concentrated solar pre-firing treatment. After pre-firing, the main phases of the tailings are wollastonite and quartz, and their microstructure changes from the original needle-like shape to a mesh-like structure, significantly increasing the specific surface area and reactivity. Then, the pre-firing wollastonite tailings are mixed with other raw materials. By precisely controlling the formula ratio and process parameters, it is ensured that the green body can achieve synergistic optimization of densification and high strength in the subsequent sintering process. In addition, the introduced light absorber plays a key role in the solar furnace heating process, improving the photothermal conversion efficiency of the green body, achieving rapid heating and mass transfer, promoting the formation of a liquid phase at low temperature and filling the pores, forming a dense structure with anorthite as the main crystalline phase and quartz as the secondary crystalline phase, thereby achieving low-temperature high-strength sintering.

[0016] Furthermore, in some embodiments, in step S1, the size of the wollastonite tailings after crushing is less than 2 mm.

[0017] Furthermore, in some embodiments, in step S2, the particle size of the wollastonite powder is D50≤15μm.

[0018] In the technical solution of this invention embodiment, controlling the particle size of wollastonite powder can further improve its dispersibility and reactivity in the billet, thereby optimizing the microstructure and mechanical properties of the final ceramic slab.

[0019] Furthermore, in some embodiments, in step S2, the mass ratio of wollastonite powder to Suzhou kaolin, potassium feldspar, sodium feldspar, quartz and light absorber is (45~55):(20~30):(10~15):(5~10):(5~10):(1~10).

[0020] In the technical solution of this invention embodiment, the light absorber accounts for approximately 1% to 10% of the mass of the powder raw material. By adjusting the proportion of light absorber, the heating rate and heat transfer efficiency of the green body in the solar furnace can be effectively controlled, thereby further optimizing the liquid phase formation behavior and densification degree during sintering. Furthermore, the selection of the light absorber must meet requirements such as high photothermal conversion efficiency, good dispersibility, and chemical compatibility with the ceramic system to ensure that it does not introduce impurities or adversely affect the performance of the final product during sintering.

[0021] Furthermore, in some embodiments, in step S2, the light-absorbing agent includes iron oxide or copper oxide.

[0022] Furthermore, in some embodiments, in step S3, granulation specifically involves adding water to the billet using a spray method for granulation; the amount of water added is 5% to 20% of the billet mass.

[0023] In the technical solution of this invention embodiment, spray drying technology is used to prepare a blank with uniform particles and good flowability, which provides a guarantee for subsequent pressing and molding.

[0024] Furthermore, in some embodiments, in step S3, the aging temperature is room temperature and the aging time is 24~48h.

[0025] In the technical solution of this invention embodiment, the aging process further improves the plasticity and bonding strength of the billet, which helps to reduce internal defects in the green billet and increase the yield.

[0026] Furthermore, in some embodiments, in step S3, the pressing molding specifically involves: pressing molding using cold isostatic pressing, with a pressure of 60~100kN and a holding time of 30~60s.

[0027] Furthermore, in some embodiments, in step S4, the drying temperature is 80~100℃ and the drying time is 24~48h.

[0028] Furthermore, in some embodiments, see Figure 1 The concentrating solar furnace includes a heliostat, a collector, and a sintering furnace body. The heliostat is used to track sunlight and reflect it to the collector. A rotating platform is set in the sintering furnace body, and the collector is used to focus sunlight onto the rotating platform in the sintering furnace body.

[0029] Secondly, embodiments of the present invention provide a ceramic slab made from wollastonite tailings pre-fired in a concentrated solar furnace, which is prepared by the preparation method described in the first aspect.

[0030] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0031] In the following embodiments of the present invention, the wollastonite tailings are sourced from Junkai New Materials Co., Ltd. The wollastonite tailings are composed of wollastonite, calcite, diopside, quartz and other impurities, wherein wollastonite accounts for 40% to 55%, calcite accounts for 5% to 15%, quartz accounts for 15% to 30%, diopside accounts for 5% to 10%, and the remainder is impurities.

[0032] Example 1 A method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace, comprising the following specific steps: (1) Pre-calcination of wollastonite tailings: After crushing and pre-treating the wollastonite tailings (size ≤ 2 mm), they are ground in a ball mill for 1 hour and pre-calcined in a concentrated solar furnace at a temperature of 800℃ for 15 minutes. Then they are cooled to room temperature to obtain pre-calcined wollastonite tailings. (2) Deep processing of pre-burned material: ball mill the pre-burned wollastonite tailings for 0.5 h and control its particle size D50≤15μm to obtain wollastonite powder; (3) Raw material mixing: The pre-burned wollastonite tailings (50 parts), Suzhou kaolin (24 parts), potassium feldspar (13 parts), sodium feldspar (5 parts), quartz (8 parts) and light absorber Fe2O3 (5 parts) were accurately weighed according to the proportion and placed in a ball mill for grinding together for 0.5 hours to obtain the billet; (4) Granulation and aging: Water (10% of the billet mass) is added to the billet by spraying and granulation is carried out. The resulting granules are aged at room temperature for 24 hours to obtain a uniform billet. (5) Green body forming: The aged green body is pressed into shape by cold isostatic pressing with a pressure of 100kN and a holding time of 60s to obtain a green body. The green body is placed in a drying oven and dried at 100℃ for 24h. (6) Firing of the green body: The dried green body is placed in a concentrated solar furnace for firing. The heating rate is 50℃ / min, the sintering temperature is 1000℃, the holding time is 15min, and the ceramic slab is obtained after cooling in the furnace.

[0033] The sintered sample from Example 1 was subjected to XRD testing and SEM testing of the rock slab cross section. Figure 2 The image shows the XRD pattern of the ceramic slab prepared in Example 1. Figure 3 This is a cross-sectional SEM image of the ceramic slab prepared in Example 1. Figure 2 The rock slab samples fired in a solar furnace showed diffraction peaks for anorthite at 1000℃, and... Figure 3 In the SEM image of the cross-section shown, the circular frame represents anorthite, and the square frame represents quartz. It can be clearly seen that the rock slab matrix is ​​dominated by granular anorthite crystals, which constitute the material's framework and provide excellent matrix strength; quartz serves as a secondary crystalline phase filling the matrix. The light-absorbing agent Fe2O3 promotes the formation of the liquid phase at a lower temperature. The liquid phase fully fills the particle pores and intergranular gaps, ultimately resulting in a highly dense and high-strength microstructure.

[0034] Figure 4 This is a SEM image of the wollastonite tailings raw material in Example 1 of the present invention; Figure 5 The image shows the XRD pattern of wollastonite tailings pre-calcined in the solar furnace in Embodiment 1 of this invention. Figure 6 This is a SEM image of the wollastonite tailings pre-calcined in the solar furnace in Example 1 of this invention. It can be seen that the main phases of the tailings after pre-calcination are wollastonite and quartz, and its microstructure changes from the original needle-like shape to a mesh-like structure, which significantly increases the specific surface area and reactivity.

[0035] Example 2 The only difference between this embodiment and Example 1 is that copper oxide is used as the light absorber, while the other steps and conditions are the same as in Example 1.

[0036] Example 3 A method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace, comprising the following specific steps: (1) Pre-calcination of wollastonite tailings: After crushing and pre-treating the wollastonite tailings (size ≤ 2 mm), they are ground in a ball mill for 1 hour and pre-calcined in a concentrated solar furnace at a temperature of 800℃ for 15 minutes. Then they are cooled to room temperature to obtain pre-calcined wollastonite tailings. (2) Deep processing of pre-burned material: ball mill the pre-burned wollastonite tailings for 0.5 h and control its particle size D50≤15μm to obtain wollastonite powder; (3) Raw material mixing: The pre-burned wollastonite tailings (50 parts), Suzhou kaolin (24 parts), potassium feldspar (13 parts), sodium feldspar (5 parts), quartz (8 parts) and light absorber Fe2O3 (10 parts) were accurately weighed according to the proportion and placed in a ball mill for grinding together for 0.5 hours to obtain the billet; (4) Granulation and aging: Water (10% of the billet mass) is added to the billet by spraying and granulation is carried out. The resulting granules are aged at room temperature for 24 hours to obtain a uniform billet. (5) Green body forming: The aged green body is pressed into shape by cold isostatic pressing with a pressure of 100kN and a holding time of 60s to obtain a green body. The green body is placed in a drying oven and dried at 100℃ for 24h. (6) Firing of the green body: The dried green body is placed in a concentrated solar furnace for firing. The heating rate is 50℃ / min, the sintering temperature is 920℃, the holding time is 15min, and the ceramic slab is obtained after cooling in the furnace.

[0037] Example 4 A method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace, comprising the following specific steps: (1) Pre-calcination of wollastonite tailings: After crushing and pre-treating the wollastonite tailings (size ≤ 2 mm), they are ground in a ball mill for 1 hour and pre-calcined in a concentrated solar furnace at a temperature of 800℃ for 15 minutes. Then they are cooled to room temperature to obtain pre-calcined wollastonite tailings. (2) Deep processing of pre-burned material: ball mill the pre-burned wollastonite tailings for 0.5 h and control its particle size D50≤15μm to obtain wollastonite powder; (3) Raw material mixing: The pre-burned wollastonite tailings (50 parts), Suzhou kaolin (24 parts), potassium feldspar (13 parts), sodium feldspar (5 parts), quartz (8 parts) and light absorber Fe2O3 (10 parts) were accurately weighed according to the proportion and placed in a ball mill for grinding together for 0.5 hours to obtain the billet; (4) Granulation and aging: Water (10% of the billet mass) is added to the billet by spraying and granulation is carried out. The resulting granules are aged at room temperature for 24 hours to obtain a uniform billet. (5) Green body forming: The aged green body is pressed into shape by cold isostatic pressing with a pressure of 100kN and a holding time of 60s to obtain a green body. The green body is placed in a drying oven and dried at 100℃ for 24h. (6) Firing of the green body: The dried green body is placed in a concentrated solar furnace for firing. The heating rate is 50℃ / min, the sintering temperature is 1000℃, the holding time is 15min, and the ceramic slab is obtained after cooling in the furnace.

[0038] Comparative Example 1 The only difference between this comparative example and Example 1 is that the sintering method provided is to fire the ceramic slabs in a traditional kiln; the specific preparation steps are as follows: (1) Pre-calcination of wollastonite tailings: After crushing and pre-treating the wollastonite tailings (size ≤2mm), they are ground in a ball mill for 1 hour and pre-calcined in a traditional kiln at a temperature of 800℃. The temperature is increased to 800℃ at a rate of 5℃ / min, and the temperature is held at 200℃, 400℃ and 600℃ for 60 minutes respectively. After holding at the highest temperature of 800℃ for 120 minutes, pre-calcined wollastonite is obtained. (2) Deep processing of pre-burned material: ball mill the pre-burned wollastonite tailings for 0.5 h and control its particle size D50≤15μm to obtain wollastonite powder; (3) Raw material mixing: The pre-burned wollastonite tailings (50 parts), Suzhou kaolin (24 parts), potassium feldspar (13 parts), sodium feldspar (5 parts), quartz (8 parts) and light absorber Fe2O3 (5 parts) were accurately weighed according to the proportion and placed in a ball mill for grinding together for 0.5 hours to obtain the billet; (4) Granulation and aging: Water (10% of the billet mass) is added to the billet by spraying and granulation is carried out. The resulting granules are aged at room temperature for 24 hours to obtain a uniform billet. (5) Green body forming: The aged green body is pressed into shape by cold isostatic pressing with a pressure of 100kN and a holding time of 60s to obtain a green body. The green body is placed in a drying oven and dried at 100℃ for 24h. (6) Firing of the blank: The dried blank is placed in a traditional kiln for firing. The temperature is raised to 1000℃ at a rate of 5℃ / min. The blank is held at 200℃, 400℃, 600℃ and 800℃ for 60min respectively. The blank is then held at the highest temperature of 1000℃ for 120min to obtain ceramic slab.

[0039] Comparative Example 2 Compared with Example 1, the difference lies in the use of a concentrating solar furnace for one-stage firing of the ceramic slabs, without pre-firing; the specific preparation steps are as follows: (1) Pretreatment of wollastonite tailings: After crushing and pretreatment of wollastonite tailings (size ≤ 2 mm), the tailings are ground in a ball mill for 1 hour to obtain wollastonite tailings powder.

[0040] (2) Raw material mixing: The pre-burned wollastonite tailings (50 parts), Suzhou kaolin (24 parts), potassium feldspar (13 parts), sodium feldspar (5 parts), quartz (8 parts) and light absorber Fe2O3 (5 parts) were accurately weighed according to the proportion and placed in a ball mill for grinding together for 0.5 hours to obtain the billet; (3) Granulation and aging: Water (10% of the billet mass) is added to the billet by spraying to granulate. The resulting granules are aged at room temperature for 24 hours to obtain a uniform billet. (4) Green body forming: The aged green body is pressed into shape by cold isostatic pressing with a pressure of 100kN and a holding time of 60s to obtain a green body. The green body is placed in a drying oven and dried at 100℃ for 24h. (5) Firing of the green body: The dried green body is placed in a concentrated solar furnace for firing. The heating rate is 50℃ / min, the sintering temperature is 1000℃, the holding time is 15min, and the ceramic slab is obtained after cooling in the furnace.

[0041] Comparative Example 3 The only difference between this comparative example and Example 1 is that no light absorber was added to the raw materials; all other steps and conditions were the same as in Example 1.

[0042] Comparative Example 4 The only difference between this comparative example and Example 1 is that the amount of Fe2O3 light absorber added to the raw materials is 15 parts, while the other steps and conditions are the same as in Example 1.

[0043] Performance testing The ceramic slabs obtained in Examples 1-4 and Comparative Examples 1-4 were subjected to performance tests. The flexural strength was tested using the three-point bending method in GB / T 6569-2006; the water absorption rate and bulk density were tested using the vacuum method in GB / T3810.3. The results are shown in Table 1 below.

[0044] Table 1. Performance test results of ceramic slabs obtained from each embodiment and comparative example.

[0045] Table 1 shows that the ceramic slab material prepared in the embodiments of the present invention has a flexural strength of 90~100MPa, a water absorption rate of 0.01%~0.05%, and a bulk density of 2.7g / cm³~2.9g / cm³. 3 All of them meet the industry standard for ceramic slabs (GB / T 44309-2024).

[0046] The test results of Comparative Example 1 show that the flexural strength of the prepared ceramic slab material is only 17 MPa, and the water absorption rate and bulk density are 21% and 1.82 g / cm³, respectively. 3 This indicates that when using a traditional kiln to fire at a maximum temperature of 1000℃, the ceramic slab remains in an unsintered state. The results of Comparative Example 1 and Example 1 effectively demonstrate that the present invention, using a concentrated solar furnace for sintering, can reduce the firing temperature range of the ceramic slab.

[0047] The test results of Comparative Example 2 show that the ceramic slab obtained by single-stage firing in a concentrating solar furnace without pre-firing has a flexural strength of 43 MPa, a water absorption rate of 0.67%, and a bulk density of 2.23 g / cm³. 3 The results did not meet the requirements of the national standard (GB / T44309-2024). This indicates that pre-calcining wollastonite tailings can help the tailings form a stable and highly active phase and structure, fundamentally ensuring the stable performance and high quality of ceramic slabs prepared from wollastonite tailings.

[0048] The test results of Comparative Examples 3 and 4 show that although the prepared ceramic slab materials can meet the industry standard for ceramic slabs (GB / T 44309-2024), their physical properties are significantly lower than those of the ceramic slabs in Example 1 with an appropriate amount of light absorber added. This indicates that not adding a light absorber or having a light absorber content exceeding a reasonable range will affect the microstructure of the ceramic slab, leading to a decrease in physical properties. Therefore, the addition of an appropriate amount of light absorber in this invention can promote the sintering of ceramic slabs and improve their physical properties. The preferred amount of light absorber in this invention is 1% to 10%.

[0049] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace, characterized in that, Includes the following steps: S1. The wollastonite tailings are crushed and ball-milled, and then placed in a concentrated solar furnace for pre-firing at a temperature of 700-800℃ for 10-15 minutes. After cooling, the pre-firing wollastonite tailings are obtained. S2. The pre-calcined wollastonite tailings are ball-milled to obtain wollastonite powder; the wollastonite powder is mixed with Suzhou kaolin, potassium feldspar, sodium feldspar, quartz and light absorber and then ball-milled to obtain a billet; S3. The billet is granulated, aged, and pressed into shape to obtain a green billet; S4. After drying the green body, place it in a concentrated solar furnace for firing at a sintering temperature of 920~1000℃ and a holding time of 10~15min. After cooling in the furnace, ceramic slabs are obtained.

2. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, In step S2, the particle size D50 of the wollastonite powder is ≤15μm.

3. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, In step S2, the mass ratio of the wollastonite powder to Suzhou kaolin, potassium feldspar, sodium feldspar, quartz and light absorber is (45~55):(20~30):(10~15):(5~10):(5~10):(1~10).

4. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, In step S2, the light-absorbing agent includes iron oxide or copper oxide.

5. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, In step S3, the granulation specifically involves adding water to the billet using a spray method for granulation; the amount of water added is 5% to 20% of the billet mass.

6. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, In step S3, the aging temperature is room temperature, and the aging time is 24~48h.

7. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, In step S3, the pressing molding specifically involves: pressing molding using cold isostatic pressing, with a pressure of 60~100kN and a holding time of 30~60s.

8. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, In step S4, the drying temperature is 80~100℃ and the drying time is 24~48h.

9. The method for preparing ceramic slabs from pre-fired wollastonite tailings in a concentrating solar furnace according to claim 1, characterized in that, The concentrating solar furnace includes a heliostat, a collector, and a sintering furnace body. The heliostat is used to track sunlight and reflect it to the collector. A rotating platform is provided in the sintering furnace body, and the collector is used to focus sunlight onto the rotating platform in the sintering furnace body.

10. A ceramic slab made from pre-fired wollastonite tailings in a concentrating solar furnace, characterized in that, The ceramic slab is prepared by the method for preparing pre-fired wollastonite tailings ceramic slabs in a concentrating solar furnace as described in any one of claims 1 to 9.

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