A method for preparing ceramic bricks based on coal-based solid waste

Abstract

This application provides a method for preparing ceramic bricks based on coal-based solid waste, belonging to the field of environmentally friendly ceramic brick production technology. The method includes: adding sodium hydroxide and silica sol aqueous solution to water glass to prepare a first silicate glass activation solution; mixing and ball milling this solution with coal gangue; diluting the mixture with water, filtering, and drying to obtain a clay-like material; adding sodium hydroxide and silica sol aqueous solution to water glass to prepare a second silicate glass activation solution, wherein the SiO2 to Na2O molar ratio is greater than that in the first silicate glass activation solution; mixing and ball milling the second silicate glass activation solution with fly ash; diluting the mixture with water, filtering, and drying to obtain a feldspar-like material; mechanically mixing and ball milling the clay-like material, feldspar-like material, and original coal-based solid waste to form a solid mixture; and pressure molding and sintering to obtain ceramic bricks. This application achieves 100% replacement of traditional ceramic raw materials with coal-based solid waste, improving the performance of ceramic bricks.

Description

Technical Field

[0001] This application relates to the field of environmentally friendly ceramic brick production technology, and in particular to a method for preparing ceramic bricks based on coal-based solid waste. Background Technology

[0002] The ceramics industry is facing a dilemma: ceramic tile production relies on raw materials such as clay, feldspar, and quartz. As production increases, the contradiction between the supply and demand of raw materials becomes increasingly prominent.

[0003] Existing technical limitations: Current methods simply physically mix typical coal-based solid wastes such as coal gangue and fly ash with other raw materials without chemical activation. As a result, fly ash and coal gangue, two typical coal-based solid wastes, can only replace quartz (to reduce shrinkage) and cannot replace clay (to bond and precipitate the mullite crystal framework) and feldspar (to flux). Furthermore, the amount added is limited (the maximum addition amount is 40%), which restricts large-scale application. Summary of the Invention

[0004] In view of this, the present application provides a method for preparing ceramic bricks based on coal-based solid waste. By chemically modifying fly ash into clay-like materials and feldspar-like materials, the clay and feldspar in traditional ceramics are replaced respectively, thereby achieving 100% replacement of traditional ceramic raw materials by coal-based solid waste (coal gangue and fly ash).

[0005] This application provides a method for preparing ceramic bricks based on coal-based solid waste, the method comprising:

[0006] A first silicate glass activation solution containing SiO2 and Na2O was prepared by adding sodium hydroxide and silica sol aqueous solution to water glass.

[0007] The first silicate glass activation solution is mixed with coal gangue and ball-milled to obtain a first mixture;

[0008] The first mixture was diluted with water, filtered, and dried to obtain a clay-like material.

[0009] A second silicate glass activation solution containing SiO2 and Na2O is prepared by adding sodium hydroxide and silica sol aqueous solution to water glass. The molar ratio of SiO2 to Na2O in the second silicate glass activation solution is greater than that in the first silicate glass activation solution.

[0010] The second silicate glass activation solution was mixed with fly ash and ball-milled to obtain a second mixture;

[0011] The second mixture was diluted with water, filtered, and dried to obtain feldspar-like material.

[0012] Clay-like materials, feldspar-like materials, and raw coal-based solid waste are mechanically mixed and ball-milled to form a solid mixture.

[0013] The solid mixture is pressure molded to obtain a green body;

[0014] The green body is sintered to obtain ceramic brick products.

[0015] According to a specific implementation of the embodiments of this application, the molar ratio of SiO2 to Na2O in the first silicate glass activation solution is 1~3, and the molar ratio of SiO2 to Na2O in the second silicate glass activation solution is 3~4.

[0016] According to a specific implementation of the embodiments of this application, the liquid-solid ratio of the first silicate glass activation liquid to coal gangue is 2:1 to 4:1, and the liquid-solid ratio of the second silicate glass activation liquid to fly ash is 2:1 to 4:1.

[0017] According to one specific implementation of the embodiments of this application, the first silicate glass activation solution and coal gangue are ball-milled at a speed of 60~300 r / min and a ball-milling time of 30~120 min.

[0018] According to one specific implementation of the present application, the second silicate glass activation solution and fly ash are ball-milled at a speed of 60~500 r / min for a time of 30-120 min.

[0019] According to a specific implementation of the embodiments of this application, when clay-like material, feldspar material and raw coal-based solid waste are mechanically mixed, the weight percentage of clay-like material is 40~60wt%, the weight percentage of feldspar material is 20~30wt%, and the weight percentage of raw coal-based solid waste is 20~30wt%.

[0020] According to one specific implementation of the embodiments of this application, the pressure for pressure molding is 30~50MPa.

[0021] According to one specific implementation of the embodiments of this application, the sintering temperature is 900~1300℃ and the sintering time is 60~180 min.

[0022] According to one specific implementation of the embodiments of this application, the ball milling speed of clay-like materials, feldspar-like materials, and raw coal-based solid waste is 60~100 r / min, and the ball milling time is 30~60 min.

[0023] According to one specific implementation of an embodiment of this application, the density of the ceramic tile product is 1~1.5 g / cm³. 3 The fracture modulus is greater than or equal to 50 MPa.

[0024] Beneficial effects:

[0025] The method for preparing ceramic bricks based on coal-based solid waste in this application utilizes chemical modification technology to transform coal gangue and fly ash into clay-like and feldspar-like materials, achieving 100% replacement of clay and feldspar in traditional ceramic raw materials and significantly reducing dependence on natural resources. This method not only effectively solves the environmental pollution problem caused by the long-term accumulation of coal-based solid waste, but also alleviates the ceramic industry's dependence on natural mineral raw materials, increases the added value of coal-based solid waste (coal gangue and fly ash), and reduces ceramic production costs, thus possessing both environmental and economic value. During the preparation process, precise control of the composition ratio, liquid-solid ratio, ball milling parameters, and subsequent pressure molding and sintering conditions of the silicate glass activation liquid ensures that the final ceramic brick product has excellent physical properties. The product contains abundant acicular mullite structures, has low density, and a rupture modulus far exceeding national standards, exhibiting excellent comprehensive performance and meeting the requirements for use in building ceramics. Furthermore, this preparation method has a clear process flow, is highly operable, and is easy to industrialize, providing a new and effective approach for the resource utilization of coal-based solid waste. This method is applicable to fields such as building ceramics and industrial ceramics, providing new ideas for solid waste utilization and sustainable development of the ceramics industry. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart of a method for preparing ceramic bricks based on coal-based solid waste according to an embodiment of the present invention;

[0028] Figure 2 This is a diagram of the internal structure of a ceramic brick according to an embodiment of the present invention. Detailed Implementation

[0029] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0030] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0032] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0033] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0034] This application provides a method for preparing ceramic bricks based on coal-based solid waste. The following refers to... Figure 1 and Figure 2 Provide a detailed description.

[0035] In one embodiment, refer to Figure 1 The method for preparing ceramic bricks based on coal-based solid waste includes the following steps:

[0036] S1, Slightly alkaline activation, preparation of clay-like materials:

[0037] A first silicate glass activation solution containing SiO2 and Na2O was prepared by adding sodium hydroxide and silica sol aqueous solution to water glass.

[0038] The first silicate glass activation solution is mixed with coal gangue and ball-milled to obtain a first mixture;

[0039] The first mixture was diluted with water, filtered and dried to obtain a clay-like material. The surface of this clay-like material contains abundant water of crystallization and hydroxyl groups, which achieve bonding through hydrogen bonds (replacing clay). It also has high reactivity, and subsequent low-temperature sintering can generate more needle-like mullite (enhancing mechanical properties).

[0040] S2, Deep alkaline activation, preparation of feldspar-like materials:

[0041] A second silicate glass activation solution containing SiO2 and Na2O is prepared by adding sodium hydroxide and silica sol aqueous solution to water glass. The molar ratio of SiO2 to Na2O in the second silicate glass activation solution is greater than that in the first silicate glass activation solution.

[0042] The second silicate glass activation solution was mixed with fly ash and ball-milled to obtain a second mixture;

[0043] The second mixture was diluted with water, filtered, and dried to obtain a feldspar-like material; this feldspar-like material contains abundant alkali metal elements and can be used as a flux (to replace feldspar).

[0044] S3. Raw material mixing: Clay-like materials, feldspar-like materials, and raw coal-based solid waste (ball-milled coal gangue, fly ash, or their mixtures can replace quartz, serving as fillers and reducing shrinkage) are mechanically mixed and ball-milled to form a solid mixture.

[0045] S4. Pressure forming: The solid mixture is pressure formed to obtain a green body;

[0046] S5. Sintering: Sintering the green body to obtain ceramic tile products.

[0047] In this embodiment, silicate glass activation solutions with different ratios are prepared, mixed with coal gangue and fly ash, ball-milled and processed to obtain clay-like materials and feldspar-like materials. These clay-like and feldspar-like materials are then mixed with raw coal-based solid waste and ball-milled to form a solid mixture. After pressure molding and sintering, ceramic brick products are obtained. The entire process ensures the full reaction and refinement of solid waste particles by precisely controlling the composition of the activation solution, liquid-to-solid ratio, ball-milling parameters, raw material mixing ratio, molding pressure, and sintering conditions. This results in a final product with excellent physical properties that meet the requirements for use in building ceramics. This method achieves 100% replacement of clay and feldspar in traditional ceramic raw materials, significantly reducing dependence on natural resources. This approach not only effectively solves the environmental pollution problem caused by the long-term accumulation of coal-based solid waste but also alleviates the ceramic industry's dependence on natural mineral raw materials, increases the added value of coal-based solid waste (coal gangue and fly ash), and reduces ceramic production costs, thus possessing both environmental and economic value.

[0048] In one embodiment, the molar ratio of SiO2 to Na2O in the first silicate glass activation solution is 1 to 3, and the molar ratio of SiO2 to Na2O in the second silicate glass activation solution is 3 to 4.

[0049] In this embodiment, by precisely controlling the molar ratio of SiO2 to Na2O in the first and second silicate glass activation solutions, different degrees of activation of coal gangue and fly ash can be achieved. The first silicate glass activation solution uses a lower SiO2 to Na2O molar ratio (1-3), which facilitates the conversion of coal gangue into clay-like materials, giving it plasticity, bonding properties, and high-temperature sintering activity similar to natural clay. The second silicate glass activation solution uses a higher SiO2 to Na2O molar ratio (3-4), which promotes the conversion of fly ash into feldspar-like materials, giving it fluxing and ceramic-forming properties similar to natural feldspar. This differentiated design allows the two solid wastes to respectively replace clay and feldspar in traditional ceramic raw materials, providing a foundation for subsequent raw material ratio and product performance optimization.

[0050] In one embodiment, the liquid-to-solid ratio of the first silicate glass activation solution to the coal gangue is 2:1 to 4:1, and the liquid-to-solid ratio of the second silicate glass activation solution to the fly ash is 2:1 to 4:1.

[0051] In this embodiment, the liquid-to-solid ratio refers to the ratio between the liquid volume and the solid mass, commonly expressed in L / kg. By setting a reasonable liquid-to-solid ratio, it is possible to ensure sufficient contact and chemical reaction between the silicate glass activation solution and the coal gangue and fly ash. If the liquid-to-solid ratio is too low, the activation solution cannot form a slurry environment with a suitable viscosity that completely encapsulates the solid waste particles, resulting in insufficient chemical activation. If the liquid-to-solid ratio is too high, it will not only waste the activation solution but may also reduce the efficiency of the mechanical activation reaction due to dilution. Therefore, controlling the liquid-to-solid ratio within the range of 2:1 to 4:1 can achieve efficient reaction between the activation solution and the solid waste, laying the foundation for the subsequent preparation of high-performance clay-like and feldspar-like materials.

[0052] In one embodiment, the first silicate glass activating solution is ball-milled with coal gangue at a speed of 60~300 r / min for a time of 30~120 min.

[0053] In this embodiment, the ball milling process is a crucial step in ensuring the thorough mixing and reaction of the silicate glass activation solution with the coal gangue through mechanical action. The control of the milling speed and time directly affects the completeness of the reaction and the performance of the final product. If the speed is too low or the time is too short, the activation solution and coal gangue may not contact sufficiently, resulting in an incomplete reaction. If the speed is too high or the time is too long, excessive grinding may lead to over-refinement of the particles, affecting subsequent molding and sintering performance. Therefore, controlling the ball milling speed within the range of 60~300 r / min and the time within the range of 30~120 min ensures a thorough reaction between the activation solution and the coal gangue, producing a high-performance clay-like material.

[0054] In one embodiment, the second silicate glass activating solution is ball-milled with fly ash at a speed of 60-500 r / min for a time of 30-120 min.

[0055] In this embodiment, the ball milling process of the second silicate glass activating solution and fly ash is equally crucial. Because the particle characteristics and reactivity of fly ash differ from those of coal gangue, different ball milling parameters are required. Controlling the ball milling speed within the range of 60~500 r / min accommodates the different sizes and hardness of fly ash particles, ensuring that the activating solution can fully penetrate and react with them. Simultaneously, controlling the ball milling time within 30~120 min ensures sufficient reaction while avoiding particle agglomeration or performance degradation caused by over-grinding. Through this ball milling process, feldspar-like materials with excellent fluxing and ceramic-forming properties can be prepared, providing high-quality raw materials for the subsequent preparation of ceramic tile products.

[0056] In practice, both the ball milling of the first silicate glass activation solution with coal gangue and the ball milling of the second silicate glass activation solution with fly ash involve a synergistic effect of "mechanical activation" and "chemical activation," ultimately achieving the transformation of the silicate network in coal gangue and fly ash from stable to active. The complete reaction mechanism is as follows:

[0057] Mechanical activation: 1) Ball milling provides the heat required for chemical reaction; 2) Crushing particles expands the reaction interface; 3) More importantly, impact / shearing causes microcracks and bond breakage in the glassy body of coal gangue and fly ash, reducing Si-O and Al-O bond energies.

[0058] Chemical depolymerization: OH groups provided by the silicate glass activating solution - Attacking the Si-O-Si / Si-O-Al bonds at defects in the silicate network breaks them, laying the foundation for subsequent chemical activation reactions.

[0059] Stabilization and replenishment: Na in silicate glass activation solution + Adsorption or binding is used to stabilize negatively charged oligomeric silicon / aluminoxanes, prevent repolymerization, and supplement active SiO2 to optimize the composition of the reaction precursor.

[0060] Final state: The dense three-dimensional silicate network is transformed into dispersed oligomeric aluminoxanes with active groups (-OH). The raw material is predominantly composed of aluminum-oxygen octahedrons [Al(VI)], while the activated fly ash is dominated by aluminum-oxygen tetrahedra (Al(IV)). The aluminum-oxygen tetrahedra (Al(IV)) gradually replace the silicon-oxygen tetrahedra in the silicate network framework. Due to the differences in bond length, bond angle, and binding energy between aluminum-oxygen tetrahedra and silicon-oxygen tetrahedra, the activated silicate three-dimensional network is less stable than the original structure. Therefore, the activated material exhibits higher reactivity during subsequent sintering and is more readily converted to mullite, thereby achieving a decrease in ceramic bulk density (lightweight) and an increase in the modulus of fracture (high strength). Based on this mechanism, the transformation of coal-based solid waste into "clay-like materials" and "quartz-like materials" can be achieved by controlling the reaction conditions.

[0061] Therefore, the silicate glass activating solution (water glass with chemically adjusted SiO2 to Na2O molar ratio) in this application does not simply act as a plasticizer. Its core function is to activate the silicate glass through the action of OH-. - The chemical depolymerization process attacks the silicate network defects in coal gangue and fly ash, combining with Na... +The stabilizing and replenishing effects of chemical agents enable the transformation of the silicate network from stable to active. This transformation not only changes the morphology and reactivity of raw material particles but also reconstructs the aluminum-oxygen coordination structure (from aluminum-oxygen octahedrons [Al(VI)] to aluminum-oxygen tetrahedra [Al(IV)]). Due to the difference in bond parameters between aluminum-oxygen tetrahedra and silicon-oxygen tetrahedra, the activated silicate three-dimensional network becomes less unstable, resulting in higher reactivity in subsequent sintering reactions and a greater tendency to transform into mullite. This leads to a decrease in ceramic bulk density (lightweight) and an increase in the modulus of fracture (high strength). Unlike traditional plasticizers that only physically improve plasticity, this chemical regulation modifies the intrinsic structure of coal-based solid waste, becoming the basis for 100% replacement of clay and feldspar, and is also the core of reducing dependence on natural resources and increasing the added value of solid waste.

[0062] In one embodiment, during the preparation of clay-like and feldspar-like materials, the drying process requires drying to a moisture content below 1 wt%. Strict control of the moisture content during drying is crucial. When the clay-like and feldspar-like materials are dried to below 1 wt%, problems such as particle agglomeration, uneven reaction, and surface cracking due to residual moisture during subsequent sintering can be effectively avoided. This not only ensures the plasticity and activity of the raw materials but also provides a stable foundation for subsequent mechanical mixing and ball milling with the original coal-based solid waste, helping to form a uniform solid mixture and thus ensuring the stable and reliable physical properties of the final ceramic tile product.

[0063] In one embodiment, when clay-like material, feldspar material, and raw coal-based solid waste are mechanically mixed, the weight percentage of clay-like material is 40-60 wt%, the weight percentage of feldspar material is 20-30 wt%, and the weight percentage of raw coal-based solid waste is 20-30 wt%.

[0064] In this embodiment, by precisely controlling the mixing ratio of various raw materials, the performance of ceramic tile products can be optimized and adjusted. Clay-like materials, as the main plasticity provider, are set at a weight percentage of 40-60 wt%, ensuring the mixture possesses sufficient plasticity and bonding properties, facilitating subsequent pressure molding operations. Feldspar-like materials, as key components for fluxing and ceramic formation, are added at 20-30 wt%, which helps form a suitable liquid phase during sintering, promoting ceramic densification and the precipitation of crystalline phases such as mullite, thereby increasing the modulus of rupture and reducing the bulk density of the ceramic tiles. The addition ratio of 20-30 wt% of raw coal-based solid waste not only achieves effective utilization of solid waste but also reduces the shrinkage of the sintered ceramic tiles through synergistic effects with other raw materials, jointly regulating the physical properties of the final product. The raw material ratio design of this embodiment provides a strong guarantee for the preparation of high-performance, environmentally friendly, and economical ceramic tile products.

[0065] In one embodiment, the pressure for pressure molding is 30~50MPa.

[0066] In this embodiment, the pressure forming process is a crucial step in determining the quality of the ceramic tile green. Placing the solid mixture in a mold and applying pressure of 30-50 MPa allows for close contact and bonding between the mixture particles, forming a green with a certain strength and density. The selection of this pressure range is critical. If the pressure is too low, the green will lack sufficient strength and density, easily leading to defects such as cracking and deformation during subsequent handling and sintering. If the pressure is too high, it may cause excessive internal stress in the green, similarly affecting the final performance of the ceramic tile. Therefore, controlling the pressure within the range of 30-50 MPa ensures that the green has sufficient strength and density, laying a good foundation for the subsequent sintering process.

[0067] In one embodiment, the sintering temperature is 900~1300℃ and the sintering time is 60~180 min.

[0068] In this embodiment, the sintering process is the final and crucial step in the ceramic tile manufacturing process, playing a decisive role in the final performance of the product. The pressure-formed green body is placed in a high-temperature furnace and sintered at a temperature range of 900–1300°C for 60–180 minutes. During this process, the raw material particles within the green body undergo a series of physicochemical changes. Too low a temperature or too short a time will result in insufficient reaction of the raw materials, leading to insufficient density and strength in the ceramic tile; while too high a temperature or too long a time may cause over-firing, resulting in product deformation, cracking, or performance degradation. Therefore, precisely controlling the sintering temperature and time ensures the formation of a uniform crystalline phase structure within the ceramic tile, optimizing the product's physical properties, such as increasing the modulus of rupture and reducing water absorption, thereby producing ceramic tile products with stable quality and excellent performance.

[0069] In one embodiment, the ball milling speed of clay-like materials, feldspar-like materials, and raw coal-based solid waste is 60~100 r / min, and the ball milling time is 30~60 min, ensuring that the particle size of the mixture after ball milling is below 250 mesh sieve.

[0070] In one embodiment, refer to Figure 2 This indicates the internal structure of the ceramic tile product, which is rich in needle-like mullite, enhancing its mechanical properties. The density of the ceramic tile product is 1~1.5g / cm³. 3 The fracture modulus is greater than or equal to 50 MPa.

[0071] The method for preparing ceramic bricks based on coal-based solid waste of this application is described below through specific embodiments.

[0072] Comparative Example 1

[0073] In this comparative example, the molar ratio of SiO2 to Na2O in the first silicate glass activation solution is 3~4, and the molar ratio of SiO2 to Na2O in the second silicate glass activation solution is also set to 3~4. All other conditions meet the conditions in the above embodiments.

[0074] In this comparative example, the molar ratio of SiO2 to Na2O in the first silicate glass activating solution was as high as 3-4 (higher than the set value of 1-3 in the above examples), leading to over-activation of the coal-based solid waste. The resulting clay-like material further transformed into feldspar-like material, resulting in a high alkali metal content in the product. In the subsequent ceramic sintering process, the excessive liquid phase caused ceramic melting and deformation. Not only did mullite and other crystalline phases fail to precipitate in sufficient quantities, but the precipitated mullite and other crystals also underwent secondary melting, and the bulk density increased significantly (greater than 1.5 g / cm³). 3 The product exhibits severe deformation and no longer meets the standards for lightweight ceramics. At the same time, its modulus of rupture is significantly reduced (far less than the 50MPa performance of the product described in this invention), resulting in a significant decrease in product performance that fails to meet the requirements of lightweight, high-strength, and other applications with high mechanical property requirements.

[0075] Comparative Example 2

[0076] In this comparative example, the molar ratio of SiO2 to Na2O in the first silicate glass activation solution is 1~3, and the molar ratio of SiO2 to Na2O in the second silicate glass activation solution is also set to 1~3. All other conditions meet the conditions in the above embodiments.

[0077] In this comparative example, because the molar ratio of SiO2 to Na2O in the second silicate glass activating liquid is only 1-3 (lower than the set value of 3-4 in the above examples), the coal-based solid waste cannot be completely converted into feldspar, resulting in a low alkali metal content in the product. In the subsequent ceramic sintering process, insufficient liquid phase cannot be formed, leading to inadequate ceramic densification and insufficient precipitation of mullite and other crystalline phases. This significantly reduces the modulus of rupture of the ceramic brick (far lower than the 50 MPa performance described in this invention), greatly diminishing the product performance and failing to meet the requirements of some applications with high requirements for mechanical properties such as modulus of rupture.

[0078] Example 1

[0079] S1, Slightly alkaline activation, preparation of clay-like materials:

[0080] A first silicate glass activation solution with a low modulus and a SiO2 to Na2O molar ratio of 1.0 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0081] The first silicate glass activation solution was mixed with coal gangue at a liquid-solid ratio of 2:1, and ball-milled for 60 minutes at a speed of 250 r / min to obtain the first mixture.

[0082] The first mixture was diluted with water, filtered, and dried to obtain a clay-like material.

[0083] S2, Deep alkaline activation, preparation of feldspar-like materials:

[0084] A second silicate glass activation solution with a high modulus and a SiO2 to Na2O molar ratio of 3.5 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0085] The second silicate glass activation solution was mixed with fly ash at a liquid-solid ratio of 4:1, and ball-milled for 90 minutes at a speed of 500 r / min to obtain the second mixture.

[0086] The second mixture was diluted with water, filtered, and dried to obtain feldspar-like material.

[0087] S3. Raw material mixing: According to the mass ratio, 30wt% raw coal gangue, 50wt% clay-like material and 20wt% feldspar-like material are mixed and ball-milled until all particles pass through a 250-mesh sieve to obtain a solid mixture.

[0088] S4. Pressure forming: Press the solid mixture into a green body under a pressure of 50MPa (ensuring the strength of the green body is greater than 6MPa).

[0089] S5. Sintering: The green body is sintered at 1250℃ for 2 hours to obtain ceramic tile products.

[0090] The ceramic tile product prepared in this example has a bulk density of 1.1 g / cm³. 3 The rupture modulus is greater than 55 MPa.

[0091] Example 2

[0092] In this embodiment, compared to Example 1, the molar ratio of the first silicate glass activating solution in step S1 is increased. Specifically, the following steps are included:

[0093] S1, Slightly alkaline activation, preparation of clay-like materials:

[0094] A first silicate glass activation solution with a low modulus and a SiO2 to Na2O molar ratio of 2.0 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0095] The first silicate glass activation solution was mixed with coal gangue at a liquid-solid ratio of 2:1, and ball-milled for 60 minutes at a speed of 250 r / min to obtain the first mixture.

[0096] The first mixture was diluted with water, filtered, and dried to obtain a clay-like material.

[0097] S2, Deep alkaline activation, preparation of feldspar-like materials:

[0098] A second silicate glass activation solution with a high modulus and a SiO2 to Na2O molar ratio of 3.5 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0099] The second silicate glass activation solution was mixed with fly ash at a liquid-solid ratio of 4:1, and ball-milled for 90 minutes at a speed of 500 r / min to obtain the second mixture.

[0100] The second mixture was diluted with water, filtered, and dried to obtain feldspar-like material.

[0101] S3. Raw material mixing: According to the mass ratio, 30wt% raw coal gangue, 50wt% clay-like material and 20wt% feldspar-like material are mixed and ball-milled until all particles pass through a 250-mesh sieve to obtain a solid mixture.

[0102] S4. Pressure forming: Press the solid mixture into a green body under a pressure of 50MPa (ensuring the strength of the green body is greater than 6MPa).

[0103] S5. Sintering: The green body is sintered at 1250℃ for 2 hours to obtain ceramic tile products.

[0104] The ceramic tile product prepared in this example has a bulk density of 1.15 g / cm³. 3 The fracture modulus is greater than 60 MPa.

[0105] Example 3

[0106] In this embodiment, compared to Example 1, the molar ratio of the second silicate glass activating solution in step S2 is reduced. Specifically, the following steps are included:

[0107] S1, Slightly alkaline activation, preparation of clay-like materials:

[0108] A first silicate glass activation solution with a low modulus and a SiO2 to Na2O molar ratio of 1.0 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0109] The first silicate glass activation solution was mixed with coal gangue at a liquid-solid ratio of 2:1, and ball-milled for 60 minutes at a speed of 250 r / min to obtain the first mixture.

[0110] The first mixture was diluted with water, filtered, and dried to obtain a clay-like material.

[0111] S2, Deep alkaline activation, preparation of feldspar-like materials:

[0112] A second silicate glass activation solution with a high modulus and a SiO2 to Na2O molar ratio of 3.0 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0113] The second silicate glass activation solution was mixed with fly ash at a liquid-solid ratio of 4:1, and ball-milled for 90 minutes at a speed of 500 r / min to obtain the second mixture.

[0114] The second mixture was diluted with water, filtered, and dried to obtain feldspar-like material.

[0115] S3. Raw material mixing: According to the mass ratio, 30wt% raw coal gangue, 50wt% clay-like material and 20wt% feldspar-like material are mixed and ball-milled until all particles pass through a 250-mesh sieve to obtain a solid mixture.

[0116] S4. Pressure forming: Press the solid mixture into a green body under a pressure of 50MPa (ensuring the strength of the green body is greater than 6MPa).

[0117] S5. Sintering: The green body is sintered at 1250℃ for 2 hours to obtain ceramic tile products.

[0118] The ceramic tile product prepared in this example has a bulk density of 1.08 g / cm³. 3 The fracture modulus is greater than 52 MPa.

[0119] Example 4

[0120] In this embodiment, compared with Embodiment 1, the raw material ratio in step S3 is changed. Specifically, it includes the following steps:

[0121] S1, Slightly alkaline activation, preparation of clay-like materials:

[0122] A first silicate glass activation solution with a low modulus and a SiO2 to Na2O molar ratio of 1.0 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0123] The first silicate glass activation solution was mixed with coal gangue at a liquid-solid ratio of 2:1, and ball-milled for 60 minutes at a speed of 250 r / min to obtain the first mixture.

[0124] The first mixture was diluted with water, filtered, and dried to obtain a clay-like material.

[0125] S2, Deep alkaline activation, preparation of feldspar-like materials:

[0126] A second silicate glass activation solution with a high modulus and a SiO2 to Na2O molar ratio of 3.5 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0127] The second silicate glass activation solution was mixed with fly ash at a liquid-solid ratio of 4:1, and ball-milled for 90 minutes at a speed of 500 r / min to obtain the second mixture.

[0128] The second mixture was diluted with water, filtered, and dried to obtain feldspar-like material.

[0129] S3. Raw material mixing: According to the mass ratio, 20wt% raw coal gangue, 50wt% clay-like material and 30wt% feldspar-like material are mixed and ball-milled until all particles pass through a 250-mesh sieve to obtain a solid mixture.

[0130] S4. Pressure forming: Press the solid mixture into a green body under a pressure of 50MPa (ensuring the strength of the green body is greater than 6MPa).

[0131] S5. Sintering: The green body is sintered at 1250℃ for 2 hours to obtain ceramic tile products.

[0132] The ceramic tile product prepared in this example has a bulk density of 1.2 g / cm³. 3 The fracture modulus is greater than 62 MPa.

[0133] Example 5

[0134] In this embodiment, compared with Embodiment 1, the liquid-to-solid ratio in steps S1 and S2 is changed. Specifically, the following steps are included:

[0135] S1, Slightly alkaline activation, preparation of clay-like materials:

[0136] A first silicate glass activation solution with a low modulus and a SiO2 to Na2O molar ratio of 1.0 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0137] The first silicate glass activation solution was mixed with coal gangue at a liquid-solid ratio of 3:1, and ball-milled for 60 minutes at a speed of 250 r / min to obtain the first mixture.

[0138] The first mixture was diluted with water, filtered, and dried to obtain a clay-like material.

[0139] S2, Deep alkaline activation, preparation of feldspar-like materials:

[0140] A second silicate glass activation solution with a high modulus and a SiO2 to Na2O molar ratio of 3.5 was prepared by adding sodium hydroxide and silica sol aqueous solution to Na2O.nSiO2 water glass to adjust the SiO2 to Na2O molar ratio.

[0141] The second silicate glass activation solution was mixed with fly ash at a liquid-solid ratio of 3:1, and ball-milled for 90 minutes at a speed of 500 r / min to obtain the second mixture.

[0142] The second mixture was diluted with water, filtered, and dried to obtain feldspar-like material.

[0143] S3. Raw material mixing: According to the mass ratio, 30wt% raw coal gangue, 50wt% clay-like material and 20wt% feldspar-like material are mixed and ball-milled until all particles pass through a 250-mesh sieve to obtain a solid mixture.

[0144] S4. Pressure forming: Press the solid mixture into a green body under a pressure of 50MPa (ensuring the strength of the green body is greater than 6MPa).

[0145] S5. Sintering: The green body is sintered at 1250℃ for 2 hours to obtain ceramic tile products.

[0146] The ceramic tile product prepared in this example has a bulk density of 1.05 g / cm³. 3 The fracture modulus is greater than 62 MPa.

[0147] The embodiments provided by this invention utilize chemical modification technology to transform coal gangue and fly ash into clay-like and feldspar-like materials, achieving 100% replacement of clay and feldspar in traditional ceramic raw materials and significantly reducing dependence on natural resources. This method not only effectively solves the environmental pollution problem caused by the long-term accumulation of coal-based solid waste, but also alleviates the ceramic industry's dependence on natural mineral raw materials, increases the added value of coal-based solid waste (coal gangue and fly ash), and reduces ceramic production costs, thus possessing both environmental and economic value. During the preparation process, by precisely controlling the composition ratio, liquid-solid ratio, ball milling parameters, and subsequent pressure molding and sintering conditions of the silicate glass activation liquid, the excellent physical properties of the final ceramic brick products are ensured.

[0148] The current industry standards for the density and modulus of rupture of lightweight ceramics are often based on the standard "Lightweight Ceramic Bricks" JC / T1095-2009. Lightweight ceramic bricks are divided into two categories according to density: Category A: 1.00 g / cm³ 3 ≤Bulk density≤ 1.50g / cm³ 3 Class B: Bulk density <1.00 g / cm³ 3 According to the modulus of rupture: Class A has an average modulus of rupture of not less than 11 MPa and an individual modulus of rupture of not less than 10 MPa; Class B has an average modulus of rupture of not less than 9 MPa and an individual modulus of rupture of not less than 8 MPa. The ceramic tile product of this application, while ensuring a very low density (excellent among Class A lightweight ceramics), has a modulus of rupture far exceeding the national and industry standards for ceramic tiles, and is far superior to existing products on the market. Therefore, the product of this application contains abundant needle-like mullite structure, has low density, and a modulus of rupture far exceeding the national standard requirements, exhibiting excellent comprehensive performance and meeting the requirements for use in building ceramics.

[0149] Furthermore, this preparation method has a clear process flow, is highly operable, and is easy to industrialize, providing a new and effective approach for the resource utilization of coal-based solid waste. This method is applicable to fields such as building ceramics and industrial ceramics, offering new ideas for solid waste utilization and the sustainable development of the ceramics industry.

[0150] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing ceramic bricks based on coal-based solid waste, characterized in that, The method includes: A first silicate glass activation solution containing SiO2 and Na2O was prepared by adding sodium hydroxide and silica sol aqueous solution to water glass. The molar ratio of SiO2 to Na2O in the first silicate glass activation solution was 1~2. The first silicate glass activation solution is mixed with coal gangue and ball-milled to obtain a first mixture; The first mixture was diluted with water, filtered, and dried to obtain a clay-like material. A second silicate glass activation solution containing SiO2 and Na2O is prepared by adding sodium hydroxide and silica sol aqueous solution to water glass. The molar ratio of SiO2 to Na2O in the second silicate glass activation solution is greater than that in the first silicate glass activation solution. The molar ratio of SiO2 to Na2O in the second silicate glass activation solution is 3.5 to 4. The second silicate glass activation solution was mixed with fly ash and ball-milled to obtain a second mixture; The second mixture was diluted with water, filtered, and dried to obtain feldspar-like material. Clay-like materials, feldspar-like materials, and raw coal-based solid waste are mechanically mixed and ball-milled to form a solid mixture. The raw coal-based solid waste includes coal gangue and fly ash. The solid mixture is pressure molded to obtain a green body; The green body is sintered to obtain ceramic brick products.

2. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, The liquid-solid ratio of the first silicate glass activation solution to coal gangue is 2:1 to 4:1, and the liquid-solid ratio of the second silicate glass activation solution to fly ash is 2:1 to 4:

1.

3. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, The first silicate glass activation solution was ball-milled with coal gangue at a speed of 60~300 r / min for a time of 30~120 min.

4. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, The second silicate glass activation solution and fly ash are ball-milled at a speed of 60~500 r / min for a time of 30~120 min.

5. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, When clay-like materials, feldspar-like materials, and raw coal-based solid waste are mechanically mixed, the weight percentage of clay-like materials is 40-60 wt%, the weight percentage of feldspar-like materials is 20-30 wt%, and the weight percentage of raw coal-based solid waste is 20-30 wt%.

6. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, The pressure for pressure molding is 30~50MPa.

7. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, The sintering temperature is 900~1300℃, and the sintering time is 60~180min.

8. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, The ball milling speed for clay-like materials, feldspar-like materials, and raw coal-based solid waste is 60~100 r / min, and the ball milling time is 30~60 min.

9. The method for preparing ceramic bricks based on coal-based solid waste according to claim 1, characterized in that, The density of ceramic tile products is 1~1.5g / cm³. 3 The fracture modulus is greater than or equal to 50 MPa.

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