Foamed ceramic and mould pressing pore-forming lamination preparation method thereof

Abstract

The invention discloses a foamed ceramic and a mould pressing pore-forming lamination preparation method thereof, and belongs to the technical field of energy-saving building material preparation, and the method comprises the following steps: firstly, forming a double-sided half-hole sheet from a ceramic raw material or pretreated industrial bulk solid waste through a mould pressing process, spraying a flux material on the surface of the double-sided half-hole sheet, and drying the double-sided half-hole sheet; and sintering the laminated layers to obtain the foamed ceramic. The size and shape of the air hole are effectively controlled through mold design, the period of a traditional foamed ceramic high-temperature foaming process is greatly shortened, functional layer coating can be achieved in the air hole, aerogel or fiber material filling can also be conducted, and high-temperature foaming is achieved. The method shows remarkable effects in the aspects of preparation process, performance improvement, cost reduction, function expansion, resource utilization and the like of the foamed ceramic, and the utilization of industrial bulk solid wastes in the field of traditional foamed ceramics is greatly promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of energy-saving building materials, and particularly relates to a foam ceramic and a method for preparing a laminated foam ceramic with holes formed by molding. Background Art

[0002] In the context of the era of green, low-carbon and sustainable development, the transformation and upgrading of the building materials industry is particularly important. With the enhancement of people's environmental awareness and the improvement of requirements for building performance, traditional building materials have gradually become difficult to meet the needs of modern buildings due to their disadvantages such as large weight, high energy consumption and heavy environmental burden. Therefore, exploring and developing new types of green building materials has become the key to promoting the green development of the construction industry. As a new type of green building material, foam ceramics show great application potential and market prospects with their excellent properties such as light weight, energy saving, high strength, heat insulation, sound absorption, noise reduction, fire resistance and flame retardancy. It can not only effectively reduce the self-weight of buildings and improve the energy efficiency ratio of buildings, but also play an active role in protecting the ecological environment and promoting the recycling of resources, and is an ideal choice for realizing energy conservation, emission reduction and sustainable development in the construction industry.

[0003] In recent years, scientific research personnel have continuously improved the performance and quality of foam ceramics by adjusting raw material formulas, optimizing preparation processes, innovating foaming technologies, etc. In terms of preparation processes, traditional methods such as slip casting, gel casting, direct foaming, etc. have been widely used, but these methods often have problems such as long preparation cycles, complex processes and high costs. In order to overcome these problems, researchers have continuously explored new preparation technologies, such as adopting advanced processes such as rapid prototyping technology (such as 3D printing), microwave sintering, freeze drying, etc., in order to achieve the high-efficiency and low-cost production of foam ceramics. At the same time, in-depth research has also been carried out on the pore structure design of foam ceramics. By controlling the size, shape and distribution of pores, the physical and mechanical properties of foam ceramics are further optimized. Although remarkable achievements have been made in the research and application of foam ceramics, a series of technical challenges are still faced. First of all, the too long preparation cycle is a major bottleneck in the current production of foam ceramics. Traditional preparation processes need to go through multiple complex steps, resulting in low production efficiency and being difficult to meet the needs of large-scale production. Secondly, the high-temperature pore formation process is difficult to precisely control. The size, shape and distribution of pores are often affected by various factors and it is difficult to achieve precise regulation, thus affecting the performance stability of foam ceramics. In addition, the high process cost is also one of the important factors restricting the wide application of foam ceramics.

[0004] In order to overcome these problems, it is urgent to develop new preparation technologies and process routes for foam ceramics to achieve the high-efficiency, low-cost and controllable preparation of foam ceramics. Summary of the Invention

[0005] In order to overcome the disadvantages of the above-mentioned prior art, the object of the present invention is to provide a foam ceramic and a method for preparing a laminated foam ceramic by die pressing and pore forming, so as to solve the technical problems of how to effectively shorten the preparation cycle of the foam ceramic, realize the precise control of the pore structure, and reduce the production cost.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a method for preparing a foam ceramic by a die pressing and pore forming lamination method, comprising the following steps: Forming a double-sided semi-hole thin sheet from ceramic raw materials or pretreated industrial bulk solid wastes through a die pressing process; spraying a flux material on the surface of the double-sided semi-hole thin sheet, and after laminating and sintering, obtaining a foam ceramic.

[0007] Preferably, the ceramic raw materials are ceramic wall and floor tile compound materials.

[0008] Preferably, the industrial bulk solid wastes include copper tailings, iron tailings, coal gangue, fly ash or red mud.

[0009] Preferably, the pressure of the die pressing process is 0.8 - 1.2 t / cm 2 ; the semi-holes in the double-sided semi-hole thin sheet are hemispherical, semi-olive spherical or semi-worm-like.

[0010] Preferably, the hole diameter of the double-sided semi-hole thin sheet is 0.2 - 10 mm.

[0011] Preferably, the double-sided semi-hole thin sheets are densely stacked in three modes of body-centered cubic packing, face-centered cubic packing or hexagonal close packing in space.

[0012] Preferably, when laminating, the semi-holes inside the double-sided semi-hole thin sheets are filled with aerogel or short fibers.

[0013] Preferably, the surface of the double-sided semi-hole thin sheet is coated with a glass with a low coefficient of thermal expansion; the surface of the double-sided semi-hole thin sheet is also coated with a functional layer, and the functional layer includes a negative ion coating, a glaze decoration layer, a fluorescent material functional layer or an electromagnetic shielding functional layer; the thickness of the functional layer is 0.1 - 0.4 mm.

[0014] Preferably, the sintering temperature is 950 - 1200 °C, and the sintering time is 10 - 30 min; the sintering is carried out in a roller hearth kiln or a tunnel kiln.

[0015] The present invention also discloses a foam ceramic prepared by the method for preparing a foam ceramic by the above-mentioned die pressing and pore forming lamination method.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method for preparing foamed ceramics by a molded pore lamination method. From a structural perspective, foamed ceramics are composed of quasi-spherical pores irregularly packed in a three-dimensional space, with inorganic materials filling the spaces between the spherical pores. After slicing the foamed ceramics, it is found that when the layer thickness is half of the average pore size, a large number of quasi-hemispherical pores cover both sides of the single-layer foam formed by cutting. From a process perspective, stacking and sintering single-layer foams can achieve the reconstruction of the foam structure in three-dimensional space. Therefore, preparing foamed ceramics by stacking single-layer foam structures can achieve precise control of pore size and shape, significantly reduce the foaming cycle, and greatly promote the application of foamed ceramics. The present invention forms double-sided semi-pore thin slices through a molding process and then prepares foamed ceramics by stacking. This method changes the traditional high-temperature foaming process to a sintering process, avoiding the uncontrollable defects of the pore structure in high-temperature foaming and achieving precise control of pore size and shape; the molding method significantly improves the strength and relative density of the product, and the sintering process replaces the foaming process to significantly shorten the process cycle, thereby greatly reducing the process cost and promoting the popularization and application of foamed ceramic products. Effective control of pore size and shape is achieved through mold design; the dependence on the amount of melt formed during the formation of the high-temperature pore structure is avoided, significantly reducing the process cycle; new functions can be imparted to the foamed ceramics through surface processes inside the ceramic pores; functional layers can be coated inside the pores, and aerogels and fibrous materials can be filled inside the pores, effectively realizing the addition of new functions to the foamed ceramics. Large-scale utilization of general bulk solid wastes, including copper tailings, iron tailings, coal gangue, fly ash, red mud, etc., can be realized.

[0017] Further, the ceramic raw material is a ceramic wall and floor tile compound, which ensures the availability and cost-effectiveness of the material, and at the same time has good ceramic properties, contributing to the formation of a stable foamed ceramic structure.

[0018] Further, using industrial bulk solid wastes as raw materials not only reduces the production cost, but also contributes to environmental protection and resource recycling, realizing the effective utilization of waste.

[0019] Further, the molding can fully compact the material and improve the density of the product. The increase in density helps to enhance the mechanical strength, hardness and wear resistance of the product. Appropriate pressure helps to reduce the pores and defects inside the product, thereby improving the overall quality of the product. By controlling the shape of the semi-pores, foamed ceramics with different pore structures can be prepared to meet different application requirements, such as filtration, heat insulation and sound absorption.

[0020] Further, the control of pore size enables the foamed ceramics to have different porosities and mechanical properties, adapting to different application scenarios.

[0021] Further, through different stacking modes, the pore structure and mechanical properties of the foamed ceramics can be optimized, such as increasing density, strength or specific thermal conductivity.

[0022] Furthermore, filling with aerogel or short fibers can enhance the heat insulation, sound insulation or mechanical properties of the foam ceramics, endowing them with new functional characteristics.

[0023] Furthermore, using glass with a low coefficient of thermal expansion helps to maintain the structural stability during sintering and reduce cracks or deformations caused by differences in thermal expansion. By coating a functional layer on the surface of the double-sided semi-hole thin sheet, new functional characteristics can be imparted to the foam ceramics, meeting more diverse application requirements. These functional layers not only enhance the practicality and aesthetics of the foam ceramics but also expand their application fields, making them have broad application prospects in multiple industries such as construction, environmental protection, electronics, and decoration.

[0024] Furthermore, the clear sintering temperature and time range, as well as the use of roller kilns or tunnel kilns, ensure the controllability and efficiency of the sintering process, contributing to large-scale production.

[0025] The present invention also discloses foam ceramics prepared by the method of preparing foam ceramics by the above-mentioned die-pressing pore-forming lamination method. The foam ceramics prepared by adopting the above method have the advantages of precise control of pore size and shape, short process cycle, low cost, and large-scale utilization of industrial bulk solid wastes, etc., and can be given new functional characteristics through functionalization treatments such as filling or coating, broadening the application scope of the foam ceramics. Description of the Drawings

[0026] Figure 1 It is a process flow chart of a method for preparing foam ceramics by a die-pressing pore-forming lamination method disclosed in the present invention. Detailed Embodiments

[0027] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention belong to the protection scope of the present invention.

[0028] In the present invention, if there is no special description, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form new technical solutions.

[0029] In the present invention, if there is no special description, all the technical features and preferred features mentioned herein can be combined with each other to form new technical solutions.

[0030] In the present invention, if there is no special description, the percentage (%) or parts refer to the weight percentage or weight parts relative to the composition.

[0031] In the present invention, unless otherwise specified, the various components involved or their preferred components can be combined with each other to form a new technical solution.

[0032] In the present invention, unless otherwise stated, the numerical range "a~b" represents an abbreviated representation of any real number combination between a and b, where both a and b are real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been fully listed herein, and "6~22" is only an abbreviated representation of these numerical combinations.

[0033] The "range" disclosed in the present invention can be in the form of one or more lower limits and one or more upper limits, respectively.

[0034] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0035] In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in order. Preferably, the reaction method herein is carried out sequentially.

[0036] Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to persons skilled in the art. In addition, any method or material similar or equivalent to the recorded content can also be applied to the present invention.

[0037] The present invention provides a method for preparing foam ceramics by a molding and pore-forming lamination method, comprising the following steps: Step 1: Using ceramic raw materials or pretreated industrial bulk solid wastes, form a double-sided semi-pore thin sheet through a molding process; Step 2: Spray a flux material low thermal expansion coefficient glass on the surface of the double-sided semi-pore thin sheet, and after laminating and sintering, obtain foam ceramics.

[0038] In Step 1, the ceramic raw material is a ceramic wall and floor tile compound; In Step 1, the industrial bulk solid wastes include copper tailings, iron tailings, coal gangue, fly ash or red mud; In Step 1, the pressure of the molding process for the double-sided semi-pore thin sheet of foam ceramics is 0.8 - 1.2 t / cm 2 ; In Step 1, the male mold and female mold used in the molding process can be designed into a hemispherical shape, a semi-olive shape or a semi-worm shape; In Step 1, the pore size of the double-sided semi-pore thin sheet is between 0.2 - 10 mm, and the thickness depends on the pore size; the double-sided semi-pore thin sheet can be coated with a functional layer, including a negative ion coating, a glaze decoration layer, a fluorescent material functional layer or an electromagnetic shielding functional layer; the thickness of the functional layer is 0.1 - 0.4 mm; In Step 1, the double-sided semi-hollow thin sheets are densely packed in space according to three patterns: body-centered cubic packing, face-centered cubic packing, or hexagonal close packing. In Step 1, the surface of the double-sided semi-hollow thin sheets can be coated with low thermal expansion coefficient glass to adapt to the rapid firing process and improve the bonding strength. In Step 2, when the double-sided semi-hollow thin sheets are stacked, a large amount of aerogel or short fibers can be filled inside the hemispherical holes to reduce the thermal conductivity and improve the sound insulation and sound absorption performance. In Step 2, the sintering temperature is 950 - 1200 °C, and the sintering time is 10 - 30 min. In Step 2, the foam ceramics can be prepared on a large scale using a roller hearth kiln or a tunnel kiln.

[0039] In the actual preparation process, at least one of ceramic wall and floor tile batch, copper tailings, iron tailings, coal gangue, fly ash, or red mud is introduced into the batch, the content of the flux material is appropriately adjusted, and foam ceramics are prepared; the pore shape, size, and arrangement are changed through the mold; a functional coating can also be applied to the surface of the hemispherical holes, and fillers can also be added during the lamination process.

[0040] The present invention forms double-sided semi-hollow thin sheets through a molding process and then stacks them, achieving precise control over the pore size and shape of the foam ceramics. By changing the traditional high-temperature foaming process to a sintering process, the process cycle is significantly shortened, thereby reducing the process cost. The molding method significantly improves the strength and relative density of the foam ceramic products. By precisely controlling the pore structure and reducing the process cost, the popularization and application of foam ceramic products are greatly promoted. New functions can be imparted to the foam ceramics through surface processes inside the ceramic pores, such as functional layer coating, aerogel or fiber internal material filling, etc. The present invention can realize the large-scale utilization of general bulk solid wastes (such as copper tailings, iron tailings, coal gangue, fly ash, red mud, etc.), and has environmental and economic benefits. It has shown remarkable effects in aspects such as the preparation process, performance improvement, cost reduction, function expansion, and resource utilization of foam ceramics.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the present invention claimed, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] Example 1 A method for preparing foam ceramics by a molded pore-forming lamination method comprises the following steps: First, the ceramic wall and floor tile mix is ​​1t / cm 2 Under pressure, after compression molding, a sheet with a thickness of 3.2mm and spherical semi-holes with a diameter of 3mm on both sides is formed. After spraying a low thermal expansion coefficient flux material on the surface, the foam ceramic body is laminated and dried. After drying, it is placed in a roller kiln for firing at a sintering temperature of 1120℃ and a firing time of 10 minutes to obtain foam ceramic.

[0043] See also Figure 1 The present invention discloses a flow chart of a method for preparing foam ceramics by a molded pore lamination method. As can be seen from the figure, ceramic raw materials or industrial bulk solid waste are mixed to form a batch material, and a double-sided half-porous thin sheet blank is formed by a molding process. These double-sided half-porous thin sheets are arranged to form a single-layer foam structure, and the half-hole is hemispherical, half-rugby or half-worm-shaped. A coating is prepared on the inner wall of the half-hole to enhance the structure or give a specific function in the subsequent sintering process; these single-layer foam structures are densely stacked to form an overall foam ceramic structure; during the lamination process, the half-holes of the double-sided half-porous thin sheets can be filled with aerogel or short fibers to increase the performance of the material. The surface of the final structure can be coated with glass with a low thermal expansion coefficient, and a functional layer can be added as needed, such as a negative ion coating, a glaze decorative layer, a fluorescent material functional layer or an electromagnetic shielding functional layer; the stacked structure is sintered in a roller kiln or a tunnel kiln to obtain a foam ceramic.

[0044] Example 2 A method for preparing foam ceramics by a molded pore-forming lamination method comprises the following steps: The copper tailings are pre-treated at 0.8t / cm 2 Under pressure, a hemispherical double-sided half-porous thin sheet with a diameter of 0.2 mm is formed through a molding process; the double-sided half-porous thin sheets are densely stacked in space according to body-centered cubic stacking, 0.1 mm low thermal expansion coefficient glass and 0.4 mm negative ion coating are sprayed on the surface of the double-sided half-porous thin sheet, aerogel is filled in the half holes of the double-sided half-porous thin sheet, and the layers are stacked and sintered at 1150° C. for 10 minutes in a roller kiln or a tunnel kiln to obtain foam ceramics.

[0045] Example 3 A method for preparing foam ceramics by a molded pore-forming lamination method comprises the following steps: The iron tailings are pre-treated at 0.9t / cm 2Under pressure, a semi-olive-shaped double-sided semi-hole thin sheet is formed by a molding process; the double-sided semi-hole thin sheets are densely packed in a face-centered cubic packing in space, a glass with a low coefficient of thermal expansion of 0.2 mm and a glaze decorative layer of 0.3 mm are sprayed on the surface of the double-sided semi-hole thin sheets, short fibers are filled in the semi-holes inside the double-sided semi-hole thin sheets, laminated, and then sintered in a tunnel kiln at 1180 °C for 15 min to obtain a foamed ceramic.

[0046] Example 4 A method for preparing a foamed ceramic by a molding and hole-forming lamination method, comprising the following steps: After the coal gangue is pretreated as raw materials, at a pressure of 1.0 t / cm 2 Under pressure, a semi-worm-shaped double-sided semi-hole thin sheet is formed by a molding process; the double-sided semi-hole thin sheets are densely packed in a hexagonal close-packed structure in space, a glass with a low coefficient of thermal expansion of 0.3 mm and a fluorescent material functional layer of 0.2 mm are sprayed on the surface of the double-sided semi-hole thin sheets, aerogel is filled in the semi-holes inside the double-sided semi-hole thin sheets, laminated, and then sintered in a roller hearth kiln at 950 °C for 20 min to obtain a foamed ceramic.

[0047] Example 5 A method for preparing a foamed ceramic by a molding and hole-forming lamination method, comprising the following steps: After the fly ash is pretreated as raw materials, at a pressure of 1.1 t / cm 2 Under pressure, a double-sided semi-hole thin sheet in the shape of a hemisphere with a diameter of 5 mm is formed by a molding process; the double-sided semi-hole thin sheets are densely packed in a face-centered cubic packing in space, a glass with a low coefficient of thermal expansion of 0.4 mm and an electromagnetic shielding functional layer of 0.1 mm are sprayed on the surface of the double-sided semi-hole thin sheets, short fibers are filled in the semi-holes inside the double-sided semi-hole thin sheets, laminated, and then sintered in a tunnel kiln at 1200 °C for 25 min to obtain a foamed ceramic.

[0048] Example 6 A method for preparing a foamed ceramic by a molding and hole-forming lamination method, comprising the following steps: After the red mud is pretreated as raw materials, at a pressure of 1.2 t / cm 2 Under pressure, a double-sided semi-hole thin sheet in the shape of a hemisphere with a diameter of 10 mm is formed by a molding process; the double-sided semi-hole thin sheets are densely packed in a hexagonal close-packed structure in space, a glass with a low coefficient of thermal expansion of 0.2 mm and a negative ion coating electromagnetic shielding functional layer of 0.2 mm are sprayed on the surface of the double-sided semi-hole thin sheets, aerogel is filled in the semi-holes inside the double-sided semi-hole thin sheets, laminated, and then sintered in a roller hearth kiln at 1150 °C for 30 min to obtain a foamed ceramic.

[0049] In summary, for the method of preparing foam ceramics by the die-pressing and hole-forming lamination method of the present invention, first, the foam ceramic raw materials are formed into double-sided semi-hole thin sheets by die-pressing. The surfaces of the double-sided semi-hole thin sheets are sprayed with flux materials, and then laminated and sintered to obtain the novel foam ceramics. The present invention realizes the effective control of the pore size and shape through die design, greatly reduces the high-temperature foaming process cycle of traditional foam ceramics, and the functional layer can be coated inside the pores, or aerogel and fiber materials can be filled, which greatly promotes the utilization of industrial bulk solid wastes in the field of traditional foam ceramics.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing foam ceramics by a molded pore-forming lamination method, characterized in that: The following steps are involved: Ceramic raw materials or pre-treated industrial bulk solid waste are formed into double-sided semi-porous thin sheets through a molding process; flux material is sprayed on the surface of the double-sided semi-porous thin sheets, and foam ceramics are obtained after stacking and sintering.

2. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: The ceramic raw material is a ceramic wall and floor tile batch material.

3. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: The bulk industrial solid waste includes copper tailings, iron tailings, coal gangue, fly ash or red mud.

4. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: The pressure of the molding process is 0.8-1.2t / cm 2 The half holes in the double-sided half-hole sheet are hemispherical, half-rugby or half-worm-shaped.

5. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: The hole diameter of the double-sided half-hole sheet is 0.2-10 mm.

6. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: The double-sided half-hole thin sheets are densely stacked in space according to three modes: body-centered cubic stacking, face-centered cubic stacking or close-packed hexagonal stacking.

7. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: During lamination, the half holes of the double-sided half-porous sheet are filled with aerogel or short fibers.

8. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: The surface of the double-sided half-hole sheet is coated with low thermal expansion coefficient glass; the surface of the double-sided half-hole sheet is also coated with a functional layer, which includes a negative ion coating, a glaze decorative layer, a fluorescent material functional layer or an electromagnetic shielding functional layer; the thickness of the functional layer is 0.1-0.4mm.

9. The method for preparing foam ceramics by molding pore forming lamination method according to claim 1, characterized in that: The sintering temperature is 950-1200° C., and the sintering time is 10-30 minutes. The sintering is carried out in a roller kiln or a tunnel kiln.

10. A foam ceramic, characterized in that: The foam ceramic is prepared by the method for preparing foam ceramic by the molding pore-forming lamination method as described in any one of claims 1 to 9.

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