Equipment for preparing foamed ceramic and preparation method thereof

Abstract

The invention provides equipment for preparing foamed ceramic and a preparation method thereof. The equipment comprises a material preparation system used for inputting and mixing all components of a blank raw material, and the blank raw material comprises a foaming agent with electromagnetic induction performance; the grinding system is used for receiving and grinding the mixed blank raw materials so as to generate powder blanks; the electromagnetic induction temperature control system comprises an external alternating current power supply and an electromagnetic heating and cooling tunnel kiln, the powder blank transferred from the grinding system is subjected to chemical reaction in the electromagnetic heating and cooling tunnel kiln to generate the foamed ceramic, and the electromagnetic induction temperature control system comprises an external alternating current power supply and an electromagnetic heating and cooling tunnel kiln. And heat required by the chemical reaction is generated by the tunnel kiln and the foaming agent under the synergistic effect of electromagnetic induction. The powder raw materials can be heated in situ through an electromagnetic induction method, an all-around efficient heating environment is formed, efficient and rapid heating and melting of the blank raw materials can be achieved, and a good environment is provided for preparation of high-quality foamed ceramics.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste resource utilization, and particularly relates to an apparatus for preparing foamed ceramics and a preparation method thereof. Background Art

[0002] Currently, coal is still one of the main energy sources in China. However, a large amount of coal ash and coal gasification slag are generated during the coal utilization process by coal chemical enterprises, leading to serious environmental pollution. Therefore, the comprehensive utilization of coal ash has become an urgent problem to be solved for modern coal chemical enterprises to achieve sustainable development.

[0003] Advantageously, the main raw materials of foamed ceramics are silicon-aluminum oxides, some alkali metal oxides and a foaming agent, which are quite similar to the main components of the minerals in the fly ash obtained during the coal combustion process and the coal gasification slag obtained during the gasification process. Furthermore, some residual carbon in the gasification slag can also function as a foaming agent. Therefore, using coal ash as the raw material for foamed ceramics can not only realize the secondary utilization of waste and save resources, but also produce foamed ceramics with high application value. Foamed ceramics are a new type of porous non-metallic material sintered at high temperature, which combines the advantages of foamed materials and ceramic materials and can be widely used in fields such as heat insulation, filters, catalyst carriers, etc. In particular, foamed ceramic materials are suitable as wall insulation materials.

[0004] However, for the preparation process of foamed ceramics, its high-temperature sintering is a high-energy-consuming process, and often a large amount of coal gas or natural gas needs to be introduced as fuel to achieve the preparation of high-quality foamed ceramic products, which increases the production cost. Moreover, there are also problems such as uneven heat supply during the heating process, which negatively affects the quality of foamed ceramics. As a result, the above-mentioned adverse factors restrict the popularization and application of foamed ceramic products.

[0005] Another existing problem is that China is the country with the fastest growth rate of global photovoltaic power generation installations. However, while photovoltaic bases generate electric energy using solar energy, they also face difficulties such as difficult grid connection, difficult power consumption, and subsidy arrears, resulting in a large amount of abandoned electricity, which not only causes serious waste of resources but also is not in line with China's promotion of sustainable economic development.

[0006] In view of this, there is a need in the art for a new apparatus for preparing foamed ceramics and a preparation method thereof. Summary of the Invention

[0007] In order to solve at least one of the above problems and defects existing in the prior art, embodiments of the present invention provide an apparatus for preparing foamed ceramics and a preparation method thereof, which use coal ash and the like as the blank raw materials for preparing foamed ceramics, heat the powdered raw materials by electromagnetic induction, and simultaneously utilize the heat generation of a foaming agent with electromagnetic induction performance to act synergistically to prepare foamed ceramics.

[0008] The technical solution is as follows:

[0009] According to one aspect of the present invention, there is provided an apparatus for preparing foamed ceramics, which comprises:

[0010] A feeding system for inputting and mixing components of a blank raw material, wherein the blank raw material at least comprises a foaming agent having electromagnetic induction performance;

[0011] A grinding system for receiving and grinding the mixed blank raw material transferred from the feeding system to produce a powder blank; and

[0012] An electromagnetic induction temperature control system, comprising an external AC power supply and a tunnel kiln connected to the external AC power supply for electromagnetic heating and cooling, and the powder blank transferred from the grinding system undergoes a chemical reaction in the tunnel kiln to generate the foamed ceramics,

[0013] wherein the heat required for the chemical reaction is generated by the synergistic action of the tunnel kiln and the foaming agent using electromagnetic induction.

[0014] Further, according to an embodiment of the present invention, the tunnel kiln may comprise a conductive pipe and an electromagnetic coil wound around the conductive pipe, and the electromagnetic coil may be connected to the external AC power supply;

[0015] wherein the conductive pipe may be partitioned into a heating part and a cooling part that communicate with each other, wherein the heating part uses electromagnetic induction to heat the powder blank to obtain an intermediate product, and the cooling part is used to receive and cool the intermediate product transferred from the heating part to obtain a finished product of the foamed ceramics.

[0016] Further, according to an embodiment of the present invention, the heating part may comprise a preheating section and a heating section that are arranged in sequence and communicate with each other, and the cooling part may comprise a cooling section, wherein the preheating section, the heating section, and the cooling section may respectively adopt independent temperature control, and the heating rates of the preheating section, the heating section, and the cooling section are respectively controlled and adjusted according to the frequency of the external AC power supply.

[0017] Further, according to an embodiment of the present invention, the temperature control range of the preheating section may be room temperature to 800 °C, and the heating rate may be 1 - 40 °C / min; the temperature control range of the heating section may be 800 °C to 1400 °C, and the heating rate may be 0.1 - 10 °C / min; the temperature control range of the cooling section may be 1400 °C to room temperature, and the cooling rate may be 0.01 - 50 °C / min.

[0018] Further, according to an embodiment of the present invention, the preheating section can reach 800 °C from the initial temperature at a heating rate of 1-40 °C / min, and then can be kept warm for 10-120 minutes; the heating section can first reach 1000-1100 °C from 800 °C at a heating rate of 1-10 °C / min, then can be kept warm for 10-120 minutes, and then can continue to reach between 1110-1270 °C at a heating rate of 0.5-3 °C / min, and then can be kept warm for 10-60 minutes; the cooling section can be cooled to room temperature at a rate of 5-50 °C / min by means of regulating the cooling gas and the current intensity of the external AC power supply.

[0019] Further, according to an embodiment of the present invention, the blank raw materials may include 10-90 parts of coal gasification slag, 5-10 parts of waste alkali salt, and 1-5 parts of foaming agent by weight percentage, wherein the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide; or

[0020] The blank raw materials may include 10-90 parts of coal gasification slag, ≤80 parts of fly ash, 5-10 parts of waste alkali salt, and 1-5 parts of foaming agent by weight percentage, wherein the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide.

[0021] Further, according to an embodiment of the present invention, the equipment may further include an exhaust gas purification system for providing a gas rich in carbon dioxide at low temperature, wherein the cooling section can be connected to the exhaust gas purification system;

[0022] The equipment may further include a curing tank for the foam ceramics that receives from the electromagnetic induction temperature control system, and the curing tank can be connected to the exhaust gas purification system.

[0023] According to another aspect of the present invention, there is provided a method for preparing foam ceramics, which includes:

[0024] Step S1 Weigh each component of the blank raw materials according to the required formula for preparing the foam ceramics, and then fully mix and stir each component, wherein the blank raw materials at least include a foaming agent having electromagnetic induction performance;

[0025] Step S2 Grind the stirred blank raw materials to produce a powder blank;

[0026] Step S3 Transfer the powder blank into an electromagnetic induction temperature control system to cause a chemical reaction of the powder blank to generate the foam ceramics, wherein the electromagnetic induction temperature control system includes an external AC power supply and a tunnel kiln for electromagnetic heating and cooling connected to the external AC power supply, and the heat required for the chemical reaction is generated by the synergistic action of the tunnel kiln and the foaming agent using electromagnetic induction.

[0027] Further, according to an embodiment of the present invention, in step S3, the electromagnetic induction temperature control system may first preheat and heat the powder blank in sequence to obtain an intermediate product, and then cool the intermediate product to obtain the finished product of the foam ceramic;

[0028] During the process of heating the powder blank, on the one hand, the electromagnetic induction temperature control system uses electromagnetic induction to heat the tunnel kiln, and then heats the powder blank placed in the tunnel kiln. On the other hand, the powder blank generates heat by electromagnetic induction at the same time;

[0029] During the process of cooling the intermediate product, it is cooled to room temperature by means of regulating the cooling gas and the current intensity of the external AC power supply to obtain the finished product of the foam ceramic.

[0030] Further, according to an embodiment of the present invention, after step S3, the finished product can be moved into a container filled with carbon dioxide for curing treatment.

[0031] The equipment and its preparation method for preparing foam ceramics provided by the embodiments of the present invention may have at least one or a part of at least one of the following advantages:

[0032] First, coal ash slag and the like are used as the blank raw materials for preparing foam ceramics, the powder raw materials are heated by electromagnetic induction, and at the same time, the synergistic effect of the foaming agent with electromagnetic induction performance generating heat is used to prepare foam ceramics. On the one hand, the powder raw materials can be in-situ heated by electromagnetic induction method to form an all-round efficient heating environment, which can eliminate the huge energy consumption, pollutant emissions, and uneven heat supply problems existing in the traditional technology due to the use of natural gas or coal as the heat source, realize the efficient and rapid heating and melting of the blank raw materials, and at the same time provide a good environment for the preparation of high-quality foam ceramics;

[0033] Second, based on the composition characteristics of coal ash slag raw materials, the present invention is compounded, and through the addition of auxiliary materials such as waste alkali liquor, foaming agent, and foam stabilizer, the decomposition processes of sodium-containing waste salt fluxes and foam stabilizers are matched, and the firing process is optimized by electromagnetic induction method, so as to prepare high-quality foam ceramics. The prepared foam ceramic material has the advantages of reasonable pore size distribution, high strength, etc.;

[0034] Third, according to the equipment and its preparation method for preparing foam ceramics of the present invention, using coal ash slag and the like as the blank raw materials for preparing foam ceramics and heating by electromagnetic induction can realize waste utilization, reduce pollutant emissions, and purify the clean environment;

[0035] Fourth, the present invention can combine the mixing and preparation process of the coal ash-based foam ceramic blank, the carbon dioxide-rich gas curing process of coal ash, and tail gas treatment, and utilize the carbon dioxide gas in the tail gas to cure the foam ceramic, which can not only utilize the resource characteristics of carbon dioxide, but also achieve carbon emission reduction. More specifically, carbon dioxide can react with the calcium components in the foam ceramic to form calcium carbonate, which can enhance the structural stability and strength of the ceramic. In addition, curing with carbon dioxide can improve the density of the foam ceramic, reduce the porosity, and further enhance the durability and compressive performance of the foam ceramic. Moreover, the above carbon emission reduction process has environmental protection advantages, reducing greenhouse gas emissions by absorbing carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of the preferred embodiments in conjunction with the accompanying drawings, in which:

[0037] Figure 1 showing an apparatus for preparing a foam ceramic according to an embodiment of the present invention;

[0038] Figure 2 showing a method for preparing a foam ceramic according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The technical solutions of the present invention will be further specifically described below through embodiments in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0040] According to an embodiment of the present invention, there is provided an apparatus for preparing a foam ceramic and a method for preparing the same, which uses coal ash and the like as the blank raw material for preparing the foam ceramic, heats the powdered raw material by electromagnetic induction, and simultaneously uses a foaming agent with electromagnetic induction performance to generate heat to act synergistically to prepare the foam ceramic. In the process of heating by electromagnetic induction, on the one hand, the present invention uses electromagnetic induction to heat a tunnel kiln for electromagnetic heating and cooling for accommodating the powdered raw material, and then heats the powdered blank placed in the tunnel kiln. On the other hand, the powdered blank simultaneously generates heat by electromagnetic induction to fully provide the chemical reaction heat required for preparing the foam ceramic, which can realize in-situ heating of the powdered raw material and form an all-round efficient heating environment, and at the same time provide a good environment for preparing high-quality foam ceramics.

[0041] According to one aspect of the present invention, as Figure 1 shown, there is provided an apparatus 100 for preparing a foam ceramic, which includes:

[0042] The stock preparation system 10 is used to input and mix the components of the blank raw material. Among them, the blank raw material includes a foaming agent with electromagnetic induction performance.

[0043] The grinding system 20 is used to receive and grind the mixed blank raw material transferred from the stock preparation system 10 to produce a powder blank.

[0044] The electromagnetic induction temperature control system 30 includes an external AC power supply and a tunnel kiln 31 connected to the external AC power supply for electromagnetic heating and cooling. Among them, the powder blank transferred from the grinding system 20 undergoes a chemical reaction in the tunnel kiln 31 to generate foam ceramics. During the chemical reaction process, the tunnel kiln 31 and the foaming agent use electromagnetic induction to cooperate to fully provide the required heat for the chemical reaction.

[0045] The key to preparing foam ceramics using coal ash slag lies in the design of the blank formula and the optimization of the firing process.

[0046] In some embodiments, the blank raw material may include 10 - 90 parts by weight of coal gasification slag, 5 - 10 parts of waste alkali salt, and 1 - 5 parts of foaming agent. Among them, the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide.

[0047] Alternatively, in some other embodiments, the blank raw material includes 10 - 90 parts by weight of coal gasification slag, ≤80 parts of fly ash, 5 - 10 parts of waste alkali salt, and 1 - 5 parts of foaming agent. Among them, the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide.

[0048] To effectively solve the problem of the utilization of coal-based solid waste, the present invention can use coal-based solid waste as the blank raw material for preparing foam ceramics, and its composition mainly includes: gasification slag, fly ash, waste alkali salt, and foaming agent, etc. The compounding and firing process of the blank raw material includes: using gasification slag and fly ash as the main raw materials, and compounding with one or several of graphite, calcium carbonate, and silicon carbide as the foaming agent, and using waste alkali salt as the flux and foam stabilizer. The above specific composition can be determined through ash melting point measurement, viscosity-temperature measurement, and in-situ preparation of foam ceramic preliminary experiments.

[0049] According to some embodiments of the present invention, the foaming agent can be selected from graphite, calcium carbonate, and silicon carbide. On the one hand, because the above foaming agent can release carbon dioxide gas after being heated and decomposed, and it is a good foaming agent itself. On the other hand, the above foaming agent has electromagnetic induction characteristics and can generate heat through electromagnetic induction. In addition, the blank raw material of the present invention may include gasification slag. As mentioned above, some residual carbon in the gasification slag can play the role of a foaming agent and also has certain electromagnetic induction characteristics, can undergo electromagnetic induction, and generate heat under high-frequency current. Moreover, because the self-heating of the foaming agent and the gasification slag belongs to in-situ heating, the heating effect will be better.

[0050] Waste alkali salts can be obtained by enrichment during the desalination process of wastewater from coal chemical enterprises. In the present invention, waste alkali liquor plays multiple roles in the preparation process of foam ceramics. First of all, waste alkali liquor, as an assistant to the gas generator, its alkaline environment can accelerate the oxidation reaction of SiC at high temperature to generate gases, such as CO and CO2 gases, thereby forming a foam structure, making the ceramic have the characteristics of light weight and porosity, and achieving ideal porosity and strength. At the same time, waste alkali liquor, as an industrial waste, can reduce the raw material cost, realize resource recycling, and improve the economy and environmental protection of the project. In addition, the composition of waste alkali liquor helps to promote the sintering reaction of raw materials, enhance the strength and compressive performance of foam ceramics, and inhibit the reaction of unstable components, making the structure of the sintered ceramic more stable and durable. Its alkalinity can also effectively adjust the pH value and surface chemical properties of foam ceramics, enhance the corrosion resistance and chemical stability of the material, and is suitable for acid-base corrosion environments.

[0051] Further, in some embodiments, the feeding system 10 may include a mixer and a pumping system. Among them, the rotational speed of the mixing blades of the mixer can be 5 - 100 revolutions per minute, and the mixing duration is not more than 2 hours.

[0052] Further, in some embodiments, the grinding system 20 may include a ball mill. Among them, one end of the above-mentioned pumping system can be connected to the mixer, and the other end can be connected to the ball mill to pump the blank raw material to the ball mill. The ball mill grinds at 300 - 500 revolutions per minute, the grinding duration ≤ 5 hours, and the particle size of the ground powder blank ≤ 150 microns.

[0053] Further, in some embodiments, as Figure 1 shown, the tunnel kiln 31 may include a conductive pipe 32 and an electromagnetic coil 33 wound around the conductive pipe 32, and the electromagnetic coil 33 can be connected to an external AC power supply.

[0054] As Figure 1 shown, the conductive pipe 32 is, for example, a metal pipe that can conduct electricity, magnetism, and heat. The conductive pipe 32 can be divided into a heating part and a cooling part that communicate with each other. Among them, the heating part can use electromagnetic induction to heat the powder blank to obtain an intermediate product, and the cooling part can be used to receive and cool the intermediate product transferred from the heating part to obtain the finished product of foam ceramics.

[0055] Further, in some embodiments, the heating part may include a preheating section 321 and a heating section 322 that are arranged in sequence and communicate with each other, and the cooling part may include a cooling section 323. Among them, the preheating section 321, the heating section 322, and the cooling section 323 can respectively adopt independent temperature control, and the heating rates of the preheating section 321, the heating section 322, and the cooling section 323 are respectively controlled and adjusted according to the frequency of the external AC power supply.

[0056] Further, in some embodiments, the temperature control range of the preheating section 321 may be from room temperature to 800 °C, and the heating rate may be 1 - 40 °C / min; the temperature control range of the heating section 322 may be from 800 °C to 1400 °C, and the heating rate may be 0.1 - 10 °C / min; the temperature control range of the cooling section 323 may be from 1400 °C to room temperature, and the cooling rate may be 0.01 - 50 °C / min.

[0057] Preferably, in some embodiments, the preheating section 321 may reach 800 °C from an initial temperature such as room temperature at a heating rate of 1 - 40 °C / min, and then may be kept warm for 10 - 120 minutes; the heating section 322 may first reach 1000 - 1100 °C from 800 °C at a heating rate of 1 - 10 °C / min, then may be kept warm for 10 - 120 minutes, and then may continue to reach between 1110 - 1270 °C at a heating rate of 0.5 - 3 °C / min, and then may be kept warm for 10 - 60 minutes; the cooling section 323 may be cooled to room temperature at a rate of 5 - 50 °C / min by means of regulating the current intensity of the cooling gas and the external AC power supply.

[0058] Further, in some embodiments, a transportation system may be provided between the grinding system 20 and the tunnel kiln 31. Among them, the transportation system may include a transport vehicle and a track for electromagnetic insulation, and the transport vehicle is movably or slidably connected to the track. Preferably, the track may be made of ceramics.

[0059] Preferably, the tunnel kiln 31 may be configured to accommodate at least one transport vehicle at the same time, and the transport vehicle may be configured to move into or out of the tunnel kiln at regular intervals.

[0060] Further, in some embodiments, the above-mentioned device 100 may further include a dispensing device removably placed on the transport vehicle. Among them, the dispensing device may include at least one insulating mold and a bracket for supporting the mold, so that the powder blank transferred from the grinding system 20 can be evenly distributed on the mold with a certain thickness and distributed into at least one layer, and the transport vehicle transfers the mold into the interior of the tunnel kiln 31. Preferably, the bracket may be made of high-temperature resistant stainless steel, and the mold may be a tray made of ceramics, preferably a tray made of aluminosilicate fiber paper.

[0061] Further, in some embodiments, the tunnel kiln 31 may accommodate at least one transport vehicle at the same time, and the transport vehicle is configured to move into or out of the tunnel kiln at regular intervals. In the case where the at least one transport vehicle includes a plurality of transport vehicles, the plurality of transport vehicles are connected in series or in parallel through a connecting device.

[0062] Further, in some embodiments, the above device 100 may further include an exhaust gas purification system for providing a low-temperature carbon dioxide-rich gas, wherein the cooling section 323 may be connected to the exhaust gas purification system.

[0063] The working method of the electromagnetic induction temperature control system 30 will be briefly described below. During the operation of the electromagnetic induction temperature control system 30, when the transportation system transfers the powder blank ground by the grinding system 20 into the electromagnetic heating and cooling tunnel kiln 31, the electromagnetic induction temperature control system 30 preheats, heats, and cools the powder blank in sequence in the preheating section, heating section, and cooling section of the tunnel kiln 31. When preheating and heating the powder blank, on the one hand, an external alternating current heats the conductive pipe inside the tunnel kiln 31 by electromagnetic induction, such as a metal pipe that can conduct electricity, magnetism, and heat, and then the above pipe heats the powder raw material; on the other hand, good electromagnetic induction is generated between the powder raw materials such as graphite, silicon carbide foaming agent with electromagnetic induction performance and gasified slag on the transport vehicle and the external alternating current, realizing in-situ heating and omnidirectional heating of the raw materials to generate intermediate products; in this process, while increasing the heating rate and ensuring the heating accuracy, compared with using natural gas or coal as the heat source in the traditional technology, the energy consumption is also reduced. Then, the transportation system transfers the intermediate product to the cooling section and inputs a low-temperature carbon dioxide-rich exhaust gas to cool the intermediate product to obtain the finished product of the foam ceramic. During the entire heat treatment process of the electromagnetic induction temperature control system 30, the preheating section 321, heating section 322, and cooling section 323 of the tunnel kiln 31 all adopt segmented independent temperature control, respectively performing different heat treatments on the powder raw materials, and the adjustment of its heating rate mainly depends on the frequency control of the external alternating current.

[0064] In addition, in some embodiments, the above device 100 may further include a curing tank 40 for receiving the foam ceramic from the electromagnetic induction temperature control system 30, and the curing tank 40 may be connected to the exhaust gas purification system.

[0065] Coupling the cooling and curing process of the foam ceramic with the exhaust gas treatment and using the carbon dioxide in the exhaust gas to cure the foam ceramic can not only utilize the resource characteristics of carbon dioxide but also achieve carbon emission reduction.

[0066] In addition, in some embodiments, the above device 100 may further include a product cutting and forming device. The cured foam ceramic product can be cut and formed according to customer requirements with the help of the product cutting and forming device.

[0067] Further, in some embodiments, the external AC power supply can be selected as a green power source to achieve efficient utilization of green power resources.

[0068] According to another aspect of the present invention, as Figure 2As shown, a method for preparing foamed ceramics is provided, which includes:

[0069] Step S1 Weigh each component of the blank raw materials according to the required formula for preparing foamed ceramics, and then fully mix and stir each component. Among them, the blank raw materials at least include a foaming agent with electromagnetic induction performance;

[0070] Step S2 Grind the stirred blank raw materials to produce a powder blank;

[0071] Step S3 Transfer the powder blank into the electromagnetic induction temperature control system 30 to cause a chemical reaction of the powder blank to generate foamed ceramics. Among them, the electromagnetic induction temperature control system 30 includes an external AC power supply and a tunnel kiln 31 connected to the external AC power supply for electromagnetic heating and cooling. Among them, the heat required for the chemical reaction is generated by the synergistic action of the tunnel kiln 31 and the foaming agent using electromagnetic induction.

[0072] Further, in some embodiments, in step S3, the electromagnetic induction temperature control system 30 can first preheat and heat the powder blank in sequence to obtain an intermediate product, and then cool the intermediate product to obtain a finished product of foamed ceramics;

[0073] During the process of heating the powder blank, on the one hand, the electromagnetic induction temperature control system 30 can use electromagnetic induction to heat the tunnel kiln 31, and then heat the powder blank placed in the tunnel kiln 31. On the other hand, the powder blank generates heat by electromagnetic induction at the same time;

[0074] During the process of cooling the intermediate product, it is cooled to room temperature by using the cooling gas and the method of regulating the current intensity of the external AC power supply to obtain a finished product of foamed ceramics.

[0075] Further, in some embodiments, after step S3, the finished product can be transferred into a container filled with carbon dioxide for curing treatment.

[0076] Further, in some embodiments, after the curing treatment step, the finished product can be subjected to product cutting and shaping treatment.

[0077] In some embodiments, the blank raw materials may include 10 - 90 parts of coal gasification slag, 5 - 10 parts of waste alkali salt, and 1 - 5 parts of foaming agent by weight percentage. Among them, the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide.

[0078] Alternatively, in some other embodiments, the blank raw materials may include 10 - 90 parts of coal gasification slag, ≤80 parts of fly ash, 5 - 10 parts of waste alkali salt, and 1 - 5 parts of foaming agent by weight percentage. Among them, the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide.

[0079] The method for preparing foamed ceramics according to the embodiments of the present invention will be illustrated by specific examples below.

[0080] Example 1

[0081] According to the present invention, for example, fine slag from China National Energy Group Yulin Coal Chemical Co., Ltd. and fly ash samples obtained from the boiler combustion of this enterprise are selected. According to the determination of ash melting point, viscosity-temperature determination and preliminary experiments on in-situ preparation of foamed ceramics, compounding is carried out according to the following formula.

[0082]

[0083] The waste alkali salt can be a mixture of sodium carbonate and sodium sulfate;

[0084] The foaming agent can be silicon carbide.

[0085] The method for preparing foamed ceramics includes the following steps:

[0086] (1) Weigh each component of the blank raw materials according to the required formula, fully stir each component at 50 revolutions per minute for 1 hour, and put them into a ball mill for grinding at 500 revolutions per minute for 2 hours. The particle size of the obtained mixture of powder raw materials is less than 150 microns.

[0087] (2) Load the powder raw materials onto a mold lined with aluminum silicate fiber paper, place three layers on a transport vehicle, and then push it into a tunnel kiln 31 for electromagnetic heating and cooling for heat treatment.

[0088] (3) The specific process of heat treatment is as follows: At the preheating section 321 of the tunnel kiln 31, the initial temperature from room temperature can reach 800 degrees at a heating rate of 9 °C per minute, and then keep warm for 40 minutes; then at the heating section 322 of the tunnel kiln 31, first reach 1100 °C at a heating rate of 7 °C per minute from 800 °C, keep warm for 80 minutes in this environment, and then reach 1130 °C at a heating rate of 1 °C per minute and keep warm for 1 hour; then at the cooling section 323 of the tunnel kiln 31, input cooling tail gas rich in carbon dioxide, and cool down to room temperature at a speed of 10 °C per minute by means of regulating the current intensity of an external AC power supply to obtain the finished product of foamed ceramics.

[0089] Example 2

[0090] According to the present invention, for example, fine slag from China National Energy Group Xinjiang Co., Ltd. and fly ash samples obtained from the boiler combustion of this enterprise are selected. According to the determination of ash melting point, viscosity-temperature determination and preliminary experiments on in-situ preparation of foamed ceramics, compounding is carried out according to the following formula.

[0091]

[0092] The above-mentioned waste alkali salt can be a mixture of sodium carbonate and sodium sulfate;

[0093] The above foaming agent can be graphite.

[0094] The method for preparing the foam ceramic includes the following steps:

[0095] (1) Weigh each component of the blank raw materials according to the required formula, fully stir the components at 50 revolutions per minute for 1 hour, and put them into a ball mill to grind at 500 revolutions per minute for 2 hours. The particle size of the obtained mixture of powder raw materials is less than 150 microns.

[0096] (2) Load the powder raw materials onto a mold lined with aluminosilicate fiber paper, stack five layers on a transport vehicle, and then push it into the tunnel kiln 31 for heat treatment.

[0097] (3) The specific process of the heat treatment is as follows: At the preheating section 321 of the tunnel kiln 31, the initial temperature from room temperature is increased to 800 degrees at a heating rate of 10 °C per minute, and then held for 60 minutes; then at the heating section 322 of the tunnel kiln 31, it is increased from 800 °C to 1100 °C at a heating rate of 5 °C per minute, held in this environment for 80 minutes, and then continued to be increased to 1130 °C at a heating rate of 3 °C per minute and held for 1 hour; then at the cooling section 323 of the tunnel kiln 31, input the tail gas rich in carbon dioxide, and by means of regulating the current intensity of the external AC power supply, cool it to room temperature at a speed of 5 °C per minute to obtain the foam ceramic of the present invention.

[0098] Comparative Example 1

[0099] Compared with Example 1, in Comparative Example 1, the waste alkali salt in Example 1 was replaced with sodium carbonate, and the other components, their contents, and the preparation process were the same.

[0100] Comparative Example 2

[0101] Compared with Example 2, in Comparative Example 2, the foam ceramic product was prepared by using traditional natural gas heating and without using carbon dioxide-rich gas curing, and its blank formula and preparation process were the same as those of Example 2.

[0102] Perform performance tests on the products prepared in Examples 1 and 2 and Comparative Examples 1 and 2 respectively. The test results are shown in Table 1. As shown in Table 1, under the test standard GB / T5486, perform the compressive strength test; under the test standard GB8642, where Class A is non-combustible, Class B1 is difficult to burn, Class B2 is combustible, and Class B3 is highly flammable, perform the combustion performance grade test; under the test standard GB / T10294, perform the thermal conductivity test; under GB / T5486, perform the density test.

[0103] Table 1 Test Results of Product Performance

[0104] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Compressive strength Mpa 0.31 0.283 0.212 0.216 Combustion performance grade A A A A <![CDATA[Thermal conductivity g / cm 3 > 0.025 0.021 0.025 0.022 <![CDATA[Density g / cm 3 > 0.294 0.256 0.292 0.223

[0105] First of all, it can be seen from the data in Table 1 that when the waste alkali salt is used to replace sodium carbonate in the product formula of Example 1, the compressive strength of the product remains basically unchanged, and the product has excellent performance. Secondly, from the comparison between Example 2 and Comparative Example 2 in Table 1, it can be seen that electromagnetic induction heating can achieve product performance similar to that of traditional heating, and carbon dioxide curing of the foam ceramic product significantly enhances the structural stability and strength of the foam ceramic product. Moreover, compared with the problems of low energy efficiency and long firing process time in the traditional gas heating process, the use of electromagnetic induction heating is more efficient, and its performance parameters can also meet the requirements of industrial applications. Moreover, when using the tail gas rich in carbon dioxide for curing, the performance of this product can be enhanced, and the product value can be increased while realizing carbon fixation.

[0106] In addition, in some embodiments, the external AC power supply can be selected as a green power source, such as new energy sources like photovoltaic, etc., to achieve the efficient utilization of green power resources.

[0107] Thus, optimally, the present invention can utilize the green power generated during the process of new energy sources such as photovoltaic, use electromagnetic induction heating to prepare the foam ceramic device, the mixing process of the coal ash slag-based foam ceramic blank, the coal ash slag carbon dioxide-rich gas curing process, and the disposal of tail gas using the chemical enterprise purification system, etc. By optimizing the organic coupling of the above processes, not only raw materials such as coal ash slag, waste salt, and carbon dioxide-rich tail gas are utilized, but also the preparation of foam ceramic products with reasonable pore size distribution and high strength is realized.

[0108] In summary, the present invention provides an efficient foam ceramic preparation device with electromagnetic induction heating function and its preparation method. It can form an all-round heating environment through electromagnetic induction, solve the problems of huge energy consumption, pollutant emissions, and uneven heat supply existing in the traditional use of natural gas or coal as a heat source, realize the efficient and rapid heating and melting of the blank, and provide a good environment for the preparation of high-quality foam ceramics.

[0109] In addition, the present invention also combines the mixing process of the coal ash slag-based foam ceramic blank and the coal ash slag carbon dioxide-rich gas curing process, makes a compound formulation based on the composition characteristics of the coal ash slag raw material, and through the addition of auxiliary materials such as foaming agents and foam stabilizers, matches the decomposition process of sodium-containing waste salt fluxes and foam stabilizers, and optimizes the firing process, finally realizing the preparation of high-quality foam ceramics.

[0110] At the same time, the present invention also couples the cooling and curing process of the foam ceramic with the tail gas treatment, uses the carbon dioxide in the tail gas to cure the foam ceramic, not only utilizes the resource characteristics of carbon dioxide, but also realizes carbon emission reduction.

[0111] This technology has the advantages of strong raw material adaptability, high energy efficiency, etc., and the prepared products have excellent quality and good market prospects.

[0112] Although some embodiments of the general inventive concept have been shown and described, those of ordinary skill in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the general inventive concept, and the scope of the invention is defined by the claims and their equivalents.

Claims

1. A device for preparing foam ceramics, characterized in that: The device comprises: A material preparation system, used for inputting and mixing various components of a blank raw material, wherein the blank raw material at least includes a foaming agent having electromagnetic induction performance; a grinding system for receiving and grinding the mixed billet raw material transferred from the material preparation system to produce a powder billet; and The electromagnetic induction temperature control system comprises an external AC power supply and a tunnel kiln connected to the external AC power supply for electromagnetic heating and cooling, wherein the powder blank transferred from the grinding system undergoes a chemical reaction in the tunnel kiln to generate the foam ceramic. The heat required for the chemical reaction is generated by the tunnel kiln and the foaming agent through the synergistic effect of electromagnetic induction.

2. The device according to claim 1, characterized in that The tunnel kiln comprises a conductive pipe and an electromagnetic coil wound around the conductive pipe, wherein the electromagnetic coil is connected to the external AC power source; The conductive pipe is divided into a heating part and a cooling part which are interconnected, wherein the heating part heats the powder blank by electromagnetic induction to obtain an intermediate product, and the cooling part is used to receive and cool the intermediate product transferred from the heating part to obtain the finished foam ceramic.

3. The device according to claim 1, characterized in that The heating part includes a preheating section and a heating section which are arranged in sequence and connected to each other, and the cooling part includes a cooling section, wherein the preheating section, the heating section and the cooling section respectively adopt independent temperature control, and the heating rates of the preheating section, the heating section and the cooling section are respectively controlled and adjusted according to the frequency of the external AC power supply.

4. The device according to claim 3, characterized in that The temperature control range of the preheating section is from room temperature to 800°C, and the heating rate is 1-40°C / min; The temperature control range of the heating section is 800°C to 1400°C, and the heating rate is 0.1-10°C / min; The temperature control range of the cooling section is 1400°C to room temperature, and the cooling rate is 0.01-50°C / min.

5. The device according to claim 4, characterized in that The preheating stage is heated from the initial temperature to 800°C at a rate of 1-40°C / min, and then kept warm for 10-120 minutes; The heating section firstly increases the temperature from 800°C to 1000-1100°C at a heating rate of 1-10°C / min, then keeps the temperature for 10-120 minutes, then continues to increase the temperature to between 1110-1270°C at a heating rate of 0.5-3°C / min, and then keeps the temperature for 10-60 minutes; The cooling section is cooled to room temperature at a rate of 5-50° C. / min by means of cooling gas and current intensity regulation of the external AC power supply.

6. The device according to claim 1, characterized in that The blank raw material comprises, by weight percentage, 10 to 90 parts of coal gasification slag, 5 to 10 parts of waste alkali salt, and 1 to 5 parts of a foaming agent, wherein the foaming agent comprises at least one of graphite, calcium carbonate, and silicon carbide; or The blank raw material includes, by weight percentage, 10 to 90 parts of coal gasification slag, ≤80 parts of fly ash, 5 to 10 parts of waste alkali salt, and 1 to 5 parts of foaming agent, wherein the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide.

7. The device according to claim 2, characterized in that The device further comprises an exhaust gas purification system for providing a low-temperature carbon dioxide-rich gas, wherein the cooling section is connected to the exhaust gas purification system; The device also includes a curing tank for receiving the foam ceramic from the electromagnetic induction temperature control system, and the curing tank is connected to the exhaust gas purification system.

8. A method for preparing foam ceramics, characterized in that: The method comprises: Step S1: weighing the components of the blank raw material according to the required formula for preparing the foam ceramic, and then fully mixing and stirring the components, wherein the blank raw material at least includes a foaming agent with electromagnetic induction performance; Step S2: grinding the stirred blank raw material to produce a powder blank; Step S3 moves the powder blank into an electromagnetic induction temperature control system to cause a chemical reaction in the powder blank to generate the foam ceramic, wherein the electromagnetic induction temperature control system includes an external AC power supply and a tunnel kiln connected to the external AC power supply for electromagnetic heating and cooling, wherein the heat required for the chemical reaction is generated by the tunnel kiln and the foaming agent using the synergistic effect of electromagnetic induction.

9. The method according to claim 8, characterized in that In step S3, the electromagnetic induction temperature control system first preheats and heats the powder blank in sequence to obtain an intermediate product, and then cools the intermediate product to obtain the finished foam ceramic; In the process of heating the powder blank, on the one hand, the electromagnetic induction temperature control system heats the tunnel kiln by electromagnetic induction, thereby heating the powder blank placed in the tunnel kiln, and on the other hand, the powder blank generates heat by electromagnetic induction at the same time; During the cooling process of the intermediate product, the intermediate product is cooled to room temperature by means of cooling gas and current intensity regulation of the external AC power source to obtain the finished foam ceramic product.

10. The method according to claim 8, characterized in that The blank raw material comprises, by weight percentage, 10 to 90 parts of coal gasification slag, 5 to 10 parts of waste alkali salt, and 1 to 5 parts of a foaming agent, wherein the foaming agent comprises at least one of graphite, calcium carbonate, and silicon carbide; or The blank raw material includes, by weight percentage, 10 to 90 parts of coal gasification slag, ≤80 parts of fly ash, 5 to 10 parts of waste alkali salt, and 1 to 5 parts of foaming agent, wherein the foaming agent includes at least one of graphite, calcium carbonate, and silicon carbide.

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