A foamed ceramic production system and method using dry powder making

Abstract

The present invention discloses a production system and method of foamed ceramics using dry powder making. The production system includes: an integrated structure of a mesh belt dryer and a kiln, and a vertical mill. The formula material enters the vertical mill after being dried by the mesh belt dryer, and does not include a granulation system for the powder material; the setting of the integrated structure of the mesh belt dryer and the kiln utilizes the kiln to supply heat to the front and rear parts of the mesh belt dryer. The present invention solves the problem of high energy consumption and power consumption caused by the continued use of wet powder making technology for existing foamed ceramics, and can save more than 40% of energy, more than 30% of electricity, more than 95% of water in the production of foamed ceramics, shorten the kiln firing cycle by more than 25%, and reduce carbon dioxide emissions by more than 40%.

Description

Technical Field

[0001] The invention belongs to the technical field of building sanitary ceramic production, and in particular relates to an energy-saving production system and method of foamed ceramics using dry powder making. Background Art

[0002] At present, the production of foamed ceramics basically still adopts the production process of traditional ceramic tile products, especially the raw material powder production still adopts the traditional wet powder production process. Its existing foamed ceramic production process consists of intermittent feeder → raw material ball mill slurry → mud storage screening and impurity removal → spray drying tower granulation → powder storage → supply cloth filling sagger → kiln → kiln firing → kiln and sagger transportation. Specifically, the wet ball mill grinds the ceramic raw materials in proportion to the required fineness of the slurry, removes impurities and iron, and then goes to the spray drying tower for granulation. The granulation process is mainly carried out in the spray drying tower. The main ceramic material is ground by wet ball milling to form a ceramic slurry with a water content of about 30%-40%, and is sprayed into the spray drying tower by a spray gun. At the same time, there is hot air of about 700℃-900℃ in the spray drying tower, so that the slurry is dried into ceramic powder particles with a water content of about 7-8%, and the powder is then spread into the sagger and fired in the kiln.

[0003] The traditional wet powder making process of foamed ceramics has the following defects:

[0004] 1. High energy consumption. Due to the limitation of the process flow, wet pulverizing must first be wet-grinded to form a slurry, and then dried, which consumes a lot of fuel (coal or natural gas) and water, and the power consumption will also increase. In the wet pulverizing process, the preparation of each ton of dry powder consumes ~85kg of coal (or ~40kg of natural gas) and ~530kg of water.

[0005] 2. Emission issues. The wet pulverizing process requires a large amount of natural gas, which will result in huge carbon dioxide emissions and increased natural gas costs. If the heat source is coal-fired, a large amount of SOx, NOx, dust and other pollutants will also be emitted.

[0006] 3. The powder is easy to be blocked when filling the sagger due to the high moisture content, especially when dry granulation is used.

[0007] 4. Since foamed porcelain is fired in a sagger and heated in one direction, the upper layer (surface) is oxidized first during the firing and cooling process. Early melting and sintering will inevitably occur during the oxidation process, which will prevent the large amount of gas generated by the lower layer during the oxidation process from escaping. In addition, due to the presence of the sagger, the heat release during the cooling process is slow as the main channel can only release upwards. As a result, the current firing time of foamed ceramics is generally around 10h to 15h, resulting in long firing time, high energy consumption, low output, and low cost, which seriously affects its large-scale promotion and application. Therefore, it is very necessary to improve the sagger structure and adjust the kiln firing process curve.

[0008] 5. The existing sagger assembly is composed of side plates, bottom plates, silicon carbide cross bearings, and silicon carbide main bearings. At present, the main bearings of manufacturers are only Fig.12 The two rods A and B in the kiln roller have been moving on the kiln roller for a long time, which causes wear marks. Generally, deep grooves will appear on the kiln roller in about three months and they need to be replaced. There are more than 7,000 kiln rollers in a kiln, and each one is worth about 300 yuan. The loss will be huge if they are replaced once.

[0009] Based on the above-mentioned problems, it can be seen that the production of foamed ceramics using traditional wet processes / systems has problems such as high energy consumption, long kiln firing time, and inability to fully utilize the waste heat of the kiln. Providing a new process / system for foamed ceramic production using ceramic dry powder making with high efficiency and energy saving has great practical significance both for environmental protection and energy saving and for controlling the cost of enterprise products. Summary of the invention

[0010] In order to improve the above technical problems, the present invention provides a production system of foamed ceramics using dry powder making, comprising: a mesh belt dryer and a kiln integrated structure, and a vertical mill, wherein the formula material is dried by the mesh belt dryer and then enters the vertical mill;

[0011] The mesh belt dryer and kiln integrated structure comprises:

[0012] Support columns, used to fix the mesh belt dryer above the kiln firing area;

[0013] Mesh belt dryer, the number of mesh belt layers is an even number not less than 2 (for example, 2 or 4 layers), the mesh belt is arranged in sections and equipped with a transmission device;

[0014] The mesh belt dryer heating pipeline is arranged on both sides of the kiln, including a smoke exhaust waste heat utilization pipeline and a cooling waste heat utilization pipeline; the smoke exhaust waste heat utilization pipeline is connected to the kiln dehumidification and smoke exhaust system to supply heat to the front of the mesh belt dryer; the cooling waste heat utilization pipeline is connected to the kiln cooling heat extraction system to supply heat to the rear of the mesh belt dryer;

[0015] The mesh belt dryer smoke exhaust device includes a heat collecting hood and a duct exhaust fan installed on the top of the mesh belt dryer, and the exhaust gas is discharged for environmental protection;

[0016] The mesh belt dryer cooling waste heat exhaust port is set in the middle of the top of the mesh belt dryer and is a long row of heat dissipation holes;

[0017] The production system does not include a granulation system for powder materials.

[0018] According to an embodiment of the present invention, the bottom of the mesh belt dryer is a cone structure with a straight hole in the middle, and a material cleaning belt is installed at the lower end of the straight hole to solve the problem of fine material falling from the belt mesh.

[0019] According to the implementation scheme of the present invention, the kiln combustion-supporting air duct is a double-sided double-tube structure, freeing up the central position for arranging the falling material collection belt and reducing the supporting height of the mesh belt dryer.

[0020] According to an embodiment of the present invention, the production system includes a formula material input device, which is used to evenly spread the formula material on the uppermost belt net, move it along the transmission direction of the kiln, and drop it to the lower belt net after reaching the end to move in the opposite direction for drying, so that moisture can be easily discharged.

[0021] According to an embodiment of the present invention, the production system comprises a batching system, preferably an online automatic batching system.

[0022] According to an embodiment of the present invention, the vertical mill is a steel slag mill using a tire roller.

[0023] According to an embodiment of the present invention, the production system includes a foaming agent storage bin, a foaming agent feeding belt, a storage bin, and a storage bin feeding belt. The foaming agent feeding belt and the storage bin feeding belt are synchronously mixed and fed to the vertical mill.

[0024] According to an embodiment of the present invention, the production system includes a finished powder homogenization bin, a dust collector, an air flow and an elevator. The powder that passes the vertical mill grinding is collected by the dust collector and then transported to the finished powder homogenization bin for storage via the air flow and the elevator; preferably, the bottom of the finished powder homogenization bin has five-channel air flow grooves evenly distributed in a fan shape, which are gathered at the discharge port to output the powder.

[0025] According to an embodiment of the present invention, the production system includes a two-stage impurity removal system, including a double flat screen or a single screen, and a high square screen, to remove impurities from the powder output from the finished powder homogenization bin.

[0026] According to an embodiment of the present invention, the production system includes a material supply and filling system, including a material supply bin, a material supply hopper and a material supply hopper moving device;

[0027] The material distribution bin is a rectangular bin with a cone structure at the bottom and is equipped with a material discharge gate;

[0028] The material distribution hopper has an upper inverted cone material receiving structure (preferably the horizontal angle of the cone surface is greater than 50 degrees) and a lower straight-through material discharging structure. After it is filled with powder, the lower gate is opened and moved longitudinally to the sagger for discharging the material.

[0029] Preferably, the lower cone of the material distribution bin and the inner wall of the material distribution hopper are sprayed with Teflon anti-stick coating to ensure smooth material distribution without sticking and clogging.

[0030] According to an embodiment of the present invention, the production system includes an atomizing surface fixing device, including an atomizer. When the foamed ceramic sagger filled with powder moves forward, the atomizer is turned on to spray water or a water liquid containing cellulose onto the surface of the powder in the sagger to ensure that the powder is not lost by the exhaust smoke when entering the negative pressure zone of the exhaust at the front end of the kiln.

[0031] According to an embodiment of the present invention, the production system comprises a sagger, including side panels, a bottom panel, a cross beam and a main beam;

[0032] The side plates and the bottom plate are both provided with hole structures, but the side plates, the bottom plate and the inclined bearing plate are not provided with hole structures;

[0033] The main beams have four main beams, two of which are close to the center and the other two are arranged at one third of the distance from the head and tail of the bottom plate; the main beams move on the kiln rollers. The present invention also provides a production method of foamed ceramics using dry powder making, including using the above production system.

[0034] In one embodiment, the production method of foamed ceramics using dry powder making comprises the following steps:

[0035] The mesh belt dryer is integrated with the kiln in design. The mesh belt dryer is placed above the kiln firing area. The waste heat from the kiln exhaust is used to supply heat to the front of the belt dryer, and the waste heat from the kiln cooling is used to supply heat to the rear of the mesh belt dryer.

[0036] According to an embodiment of the present invention, the production method also includes: vertical mill avoids peak and valley electricity production, that is, arranges batching and drying along with the kiln to produce and dry the formulated materials 24 hours a day. During the peak electricity consumption, the vertical mill is not started, and the dried materials are stored in a peak-avoiding storage bin.

[0037] According to an embodiment of the present invention, the production method further includes: atomizing water to fix the surface, that is, after the powder is arranged in the sagger, the water volume is adjusted, and water or aqueous liquid containing cellulose is sprayed on the surface when the sagger moves toward the kiln to ensure that the powder is not lost by the exhaust smoke when entering the negative pressure zone of the front exhaust of the kiln.

[0038] According to an embodiment of the present invention, the production method further comprises: drilling holes in the bottom plate of the sagger, sintering the bottom first, and then gradually moving upward; and at the same time, drilling holes in the side plates of the sagger to enhance the heat exchange of the powder sintering in the bowl.

[0039] According to an embodiment of the present invention, the production method further comprises: before 1000°C, the surface temperature gun of the oxidation sintering zone shall be closed and no heat shall be supplied, so as to cause a huge temperature difference between the upper and lower parts, forcing the foaming sintering oxidation to start from the bottom and gradually move upward, ensuring that the top layer is sintered last to facilitate exhaust, and accelerating this process by appropriately increasing the lower temperature, thereby achieving the purpose and result of fast sintering;

[0040] At the same time, during cooling, the arrangement of rapid cooling blowing and slow cooling exhaust is increased. When there are holes in the lower plate of the sagger, heat can be dissipated from both the upper and lower parts, which is conducive to the rapid cooling of the foam board and avoids the damage caused by shrinkage stress cracks when the one-way cooling speed is too fast. In this way, the goal of reducing the cooling time is achieved, the kiln firing time is shortened, and the purpose of reducing energy consumption and increasing production is achieved.

[0041] The invention also provides application of the system or method in producing foamed ceramics.

[0042] Beneficial Effects

[0043] The invention systematically solves the problem of high energy and electricity consumption caused by the wet powder making technology used in existing foamed ceramics, and can save more than 40% of energy, more than 30% of electricity, more than 95% of water in the production of foamed ceramics, shorten the kiln firing cycle by more than 25%, and reduce carbon dioxide emissions by more than 40%. It also lays the foundation for factory automation and intelligent production, which is beneficial to the country and the people. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of the energy-saving production system of foamed ceramics using dry powder making;

[0045] Figure numbers: 1-1 raw material batching bin, 1-2 mesh belt dryer, 1-3 kiln, 1-4 raw material storage bin, 1-5 foaming agent injection device, 1-6 vertical mill, 1-7 main dust collector, 1-8 finished powder homogenization bin, 1-9 spare powder homogenization bin, 1-10 secondary impurity removal system, 1-11 material supply and filling system, 1-12 sagger after filling (not atomized and solidified), 1-13 atomization and solidification device, 1-14 sagger after filling (atomized and solidified), 1-15 empty sagger after unloading.

[0046] Figure 2 It is a schematic diagram of the integrated structure of the mesh belt dryer and the kiln;

[0047] Figure numerals: 2-1 kiln dehumidification and smoke exhaust system, 2-2 mesh belt dryer, 2-3 blank cleaning belt, 2-4 kiln cooling and heat extraction system, 2-5 kiln, 2-6 kiln unloading and ferrying system.

[0048] Figure 3 Structural diagram of the online batching system;

[0049] Figure numerals: 1-1 raw material batching bin, 3-1 conveyor belt, 3-2 belt electronic scale, 3-3 conveyor belt for formula materials, 3-4 unloading and sealing.

[0050] Figure 4 It is a structural schematic diagram of a mesh belt dryer;

[0051] Figure numerals: 4-1 batching conveyor belt, 4-2 batching spreading device, 4-3 smoke exhaust waste heat utilization pipeline, 4-4 mesh belt dryer smoke exhaust device, 4-5 cooling waste heat utilization pipeline, 4-6 mesh belt dryer cooling waste heat exhaust port, 4-7 mesh belt, 2-3 blanking cleaning belt, 2-5 kiln.

[0052] Figure 5 It is a structural schematic diagram of the finished powder homogenization bin;

[0053] Figure numbers: 1-8 finished powder homogenizing bin, 5-1 to 5-5 air flow troughs, 5-6 elevator inlet.

[0054] Figure 6 It is a structural schematic diagram of the secondary impurity removal system;

[0055] Figure numbers: 6-1 screen inlet elevator, 6-2 screen inlet air chute, 6-3 silo, 6-4 sealer, 6-5 double flat screen, 6-6 high square screen, 6-7 elevator inlet air chute, 6-8 screen outlet air chute, 6-9 screen outlet elevator, 6-10 elevator outlet air chute.

[0056] Figure 7 It is a structural schematic diagram of the cloth feeding box system;

[0057] Figure numerals: 7-1 material distribution bin, 7-2 material distribution hopper, 7-3 material distribution hopper moving device, 7-4 sagger, 7-5 first gate plate, 7-6 second gate plate.

[0058] Figure 8 It is a schematic diagram of the atomization surface fixing device;

[0059] Figure numerals: 8-1 mobile platform, 8-2 atomizing device, 7-4 sagger.

[0060] Fig. 9 This is a schematic diagram of the kiln structure;

[0061] Figure number: 9-1 kiln combustion air duct.

[0062] Fig.10 Schematic diagram of the hole distribution of the sagger bottom plate.

[0063] Fig.11 Schematic diagram of the distribution of heat conduction holes on the side plate of the sagger.

[0064] Fig.12This is a schematic diagram of the structure of the sagger;

[0065] Figure numerals: 12-1 main beam, 12-2 cross beam, 12-3 bottom plate, 12-4 side plate. DETAILED DESCRIPTION

[0066] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0067] The present invention relates to an energy-saving production system and method for foamed ceramics using dry powder making. The technical difficulty lies in that when using the ceramic dry powder making process technology, only the grinding step in the dry powder making process is used and the granulation step is eliminated. At least the following problems are solved: the problem of easy blockage of powder in the filling sagger and the problem of powder loss caused by dust entering the kiln during firing are solved; the integrated design of the mesh belt dryer and the kiln is added to make full use of the waste heat of the kiln to achieve energy-saving effects, and the production needs of saving electricity during valley peaks and avoiding peaks are fully considered, and the sagger structure is improved so that it can be heated, sintered and oxidized from the bottom, while adjusting the kiln firing curve to promote exhaust and cooling. Specifically embodied in:

[0068] 1. Since there is no granulation process, it is necessary to solve the problem of dispersion and homogenization of the foaming agent during grinding, the problem of anti-sticking during distribution, and the problem of powder dust loss during sintering into the kiln.

[0069] 2. In order to solve the problem of dispersion and homogenization of the foaming agent, it is necessary to use a belt dryer to dry the formula material to a moisture content of less than 2%. At the same time, a separate silo and belt scale should be set up before the foaming agent enters the vertical mill for accurate online measurement so that it can be fed into the mill along with the formula material.

[0070] 3. In order to achieve energy saving and consumption reduction, the belt dryer is integrated with the kiln, so that the kiln exhaust and cooling exhaust waste heat can be fully utilized.

[0071] 4. In order to achieve the goal of saving electricity, on the basis of drying raw materials to improve the efficiency of the mill, a raw material warehouse of about 500 tons is installed in front of the vertical mill to receive the dried raw materials for the dryer when the vertical mill stops production during peak hours.

[0072] 5. The present invention does not carry out granulation. When the fine powder is filled into the sagger and fed into the kiln, the negative pressure caused by the exhaust of the kiln smoke and ventilation will cause the powder to be lost. After the powder fills the sagger, it is necessary to spray water or a solution containing cellulose to solidify the surface.

[0073] 6. The inventor found that the bottom and sides of the sagger are closed, which is not conducive to the heating, oxidation and cooling of the foamed ceramic from the bottom. It is necessary to drill holes in the bottom and sides of the sagger so that it can also be heated and cooled from the bottom and sides. At the same time, in order to prevent the upper layer from sintering later than the bottom layer and facilitate the exhaust of the lower and middle layers, the surface temperature heating of the oxidation zone should be turned off.

[0074] Based on the above considerations, the present invention re-arranges and designs the foamed ceramic production system (see Figure 1 ). The system includes: a raw material batching bin 1-1, a mesh belt dryer 1-2, a kiln 1-3, a raw material storage bin 1-4, a foaming agent injection device 1-5, a vertical mill 1-6, a main dust collector 1-7, a finished powder homogenizing bin 1-8, a spare powder homogenizing bin 1-9, a secondary impurity removal system 1-10, a material supply and distribution filling system 1-11, a post-filling sagger (not atomized and solidified) 1-12, an atomized and solidified device 1-13, a post-filling sagger (atomized and solidified) 1-14, and an empty sagger after unloading 1-15. The corresponding production process is as follows: online integrated storage and metering batching → formula material mesh belt dryer drying → peak avoidance storage bin → vertical mill powder grinding and powder collection → finished powder homogenizing bin → secondary impurity removal screen → material supply and distribution system → atomized water solidification → firing → kiln tail unloading and ferrying. The present invention makes full use of the applicant's existing technical achievements in dry powder making, creatively perfects and improves the continuous progress and system integrity of ceramic dry powder making technology, so that this new system / method can become the future iterative technology of the ceramic industry.

[0075] The batching process uses an online automatic batching system to continuously supply materials. There are 8 to 10 batching points. The feeding method can be a small warehouse forklift to replenish materials or a warehouse-type 1000-2000-ton large warehouse automatic unloading method to feed materials to the belt scale (see Figure 3 The online batching system includes: a raw material batching bin 1-1, a conveying belt 3-1, a belt electronic scale 3-2, a conveying formula material belt 3-3, and a material unloading seal 3-4. Figure 3 The online batching system is shown. The first method is to use a small-capacity square silo and shovel to replenish materials; the second method is to use a large-capacity 1000-2000-ton storage silo for direct unloading. Both methods require the unloading to be moved through the thickened conveyor belt 3-1 at the outlet, and the materials are linked to the belt electronic scale 3-2, and then accumulated on the conveyor formula material belt 3-3 to supply the fabric to the mesh belt dryer. The large-capacity storage silo is designed to be round on the top and conical on the bottom, and the unloading seal 3-4 is installed at the discharge port. A 10mm thick high-pressure anti-sticking plate is installed on the lower conical surface of the two silos, and the belt adopts an anti-sticking smooth belt. The order of silo loading is set from front to back according to the moisture content of the raw materials to ensure that the dry materials contact the belt first, and the wet materials fall on the dry materials to ensure that they do not stick to the belt.

[0076] The formula material is dried using a mesh belt dryer (see Figure 2 , Figure 4). Since the main raw materials used in foamed ceramics are mostly tailings waste mud, its water content is generally high, usually around 23%. After mixing with other materials, its moisture content is still as high as about 15%. Vertical mill production does not need to be heated when the moisture content of the medium does not exceed 2%. In this way, this mixture must be heated when grinding in the vertical mill using the dry powder making method for normal production, and the energy consumption is meaningless compared to the energy saved by using dry technology. Since foamed ceramic production does not require drying of blanks as in ceramic tile production, there is a large amount of smoke exhaust and cooling up to 200 to 250 degrees preheating that can be used. In order to make full use of preheating and space, reduce waste heat long-distance transmission losses and investment, the integrated structure of the mesh belt dryer and kiln is placed above the kiln firing area. The integrated structure of the mesh belt dryer and kiln includes:

[0077] Support columns, used to fix the mesh belt dryer above the kiln firing area;

[0078] Mesh belt dryer 2-2, the number of mesh belt layers is an even number not less than 2 (for example, 2 or 4 layers), the mesh belt is arranged in sections and equipped with a transmission device;

[0079] The mesh belt dryer heating pipeline is arranged on both sides of the kiln 2-5, including a smoke exhaust waste heat utilization pipeline 4-3 and a cooling waste heat utilization pipeline 4-5; the smoke exhaust waste heat utilization pipeline 4-3 is connected to the kiln dehumidification and smoke exhaust system 2-1, and is used to supply heat to the front of the mesh belt dryer 2-2; the cooling waste heat utilization pipeline 4-5 is connected to the kiln cooling heat extraction system 2-4, and is used to supply heat to the rear of the mesh belt dryer 2-2;

[0080] The mesh belt dryer smoke exhaust device 4-4 includes a heat collecting cover and a duct exhaust fan installed on the top of the mesh belt dryer, and the exhaust gas is discharged for environmental protection;

[0081] The mesh belt dryer cooling waste heat exhaust port 4-6 is set at a heat dissipation hole about 1m in the middle of the top of the mesh belt dryer for direct discharge. The length of the mesh belt dryer is calculated according to the amount of moisture dried, and the width is designed according to the maintenance width of the kiln. The supporting column is passively measured and provided with rod extraction holes in the kiln to facilitate the maintenance and extraction of rods in the kiln. The mesh belt is designed to be 30m to 50m in sections according to the load capacity. The inlet and outlet of the dried material are designed in the direction of the kiln, and the wet material entry is designed in the upper layer. The formulated material is fed in through the batching conveyor belt 4-1 and evenly distributed through the batching spreading device 4-2. The dry material discharge is designed in the lower layer and is conveyed to the peak avoidance storage bin by the belt. The mesh belt is a 304 stainless steel herringbone mesh. The sides of the dryer are normally insulated, and the bottom is designed as an inclined cone from the midline of both directions. A long hole for blanking is opened in the middle. The hole is a 400mm∽500mm straight hole. A blanking cleaning belt 2-3 is installed at the lower end of the straight hole to solve the problem of fine material falling from the belt mesh and collect it on the drying material conveyor belt.

[0082] The formula material dried from the mesh belt dryer is transported to the peak storage bin through the conveyor belt for storage and standby. A foaming agent batching bin and a belt scale are installed before the vertical mill, and the batching and feeding are synchronized online during the vertical mill production. This feeding belt is set as a large-angle belt or elevator. After the powder is ground by the vertical mill, it is collected by the dust collector and transported to the finished powder through the air flow trough and elevator for homogenization and color storage.

[0083] The peak-avoiding storage silo is designed to save electricity and reduce costs for the production line. As the vertical mill is the largest power consumer in the factory, it is of great significance to control the production cost of foamed ceramics by allowing the vertical mill to produce electricity during the peak and valley periods. Since the kiln is a continuous production, waste heat is generated all day long from the beginning to the end. In this way, the batching and drying are arranged to dry the formula materials with the kiln 24 hours a day. When the power consumption peaks, the vertical mill is not started and the dried materials are stored in the peak-avoiding storage silo. The volume of the peak-avoiding storage silo is designed to be two-thirds of the powder consumption for the whole day.

[0084] The main consideration for vertical mill powder collection is the selection of vertical mill. When grinding ceramic raw materials, the vertical mill does not use a variety of raw materials with different hardness and mud and stone, unlike cement, which has a large proportion of main materials and a single medium of ore and steel slag. It is difficult to form a material layer during grinding and is very easy to vibrate. Therefore, it is more suitable to choose a tire roller. The vertical mill 1-6 is selected as a steel slag mill, and the output is selected as 2.5 times the amount of raw materials required for daily production. In order to ensure uniform grinding of the foaming agent, a foaming agent storage bin and a matching precision belt scale are required before the formula material enters the vertical mill, and the mixing and feeding are synchronized with the feeding belt of the peak-avoiding storage bin. The powder that passes the vertical mill grinding is collected by the dust collector and then transported to the homogenization bin for storage through air flow and elevator.

[0085] Finished powder homogenizing bin 1-8 is a single powder storage bin made of threaded plate (see Figure 5 ). The powder storage bin is designed to store 4 days of raw materials. Five air flow slots 5-1 to 5-5 are evenly distributed in a fan shape at the bottom of the bin and converge at one point to output the powder to the elevator entrance 5-6, and then go to the secondary impurity removal system for impurity removal. In actual operation, the five air flow slots can work intermittently to ensure the uniformity of the powder, forming regional gaps to promote the full intersection and mixing of powders in different time periods.

[0086] The secondary impurity removal system is used to remove fibers and coarse particles in the powder to prevent cracks and breakage of the foamed ceramic during sintering. The primary impurity removal is aimed at removing fiber impurities, and requires a screen of 30-40 mesh. The primary impurity removal is aimed at removing large particle impurities, and requires a screen of 60-80 mesh. A 1-hour turnover bin is set on the top of the primary impurity removal to ensure continuous production of the screening machine. At the same time, the primary screening machine is designed on the upper platform. The screened powder is directly connected to the secondary screening machine for screening. The qualified powder after screening is directly transported to the elevator and air flow trough to the distribution bin (see Figure 6The secondary impurity removal system includes: screen inlet elevator 6-1, screen inlet air chute 6-2, silo 6-3, sealer 6-4, double flat screen 6-5, high square screen 6-6, inlet elevator air chute 6-7, screen outlet air chute 6-8, screen outlet elevator 6-9, and outlet elevator air chute 6-10. First, the powder is transported to the silo for storage through the elevator, and then discharged through the sealer to the primary fiber impurity removal double flat screen (can also be replaced by a single screen) for impurity removal, and then collected to the secondary high flat screen mainly composed of particles for impurity removal. After impurity removal, the qualified powder is transported to the distribution system through the air flow trough and elevator.

[0087] The material supply system is composed of a material supply bin 7-1, a material supply hopper 7-2 and a material supply hopper moving device 7-3 (see Figure 7 ). The material distribution bin is designed as an upper rectangular bin and a lower cone structure. The horizontal angle of the cone is >50 degrees. The length of the discharge port is designed according to the width of the sagger 7-4, and the width is designed to be 200mm. The conical surface is sprayed with a Teflon anti-sticking layer, and the discharge is controlled by a gate (including the first gate 7-5 and the second gate 7-6. The material distribution vehicle is distributed by a movable distribution hopper. The volume of the distribution hopper is designed to be 1.5 times the amount of a single sagger. The distribution hopper is designed to have an upper inverted cone for receiving materials and a lower straight-through material distribution structure. The distribution is controlled by a horizontal gate. After it is filled with powder, the lower gate is opened and moved longitudinally to the sagger for distribution. The sagger should be distributed according to the thickness required by the filling powder and particle process. The lower cone of the distribution bin and the inner wall of the distribution hopper are required to be sprayed with a Teflon anti-stick coating. To ensure smooth distribution without sticking.

[0088] The atomizing surface fixing device includes a moving platform 8-1 and an atomizing device 8-2. After the powder is arranged in the sagger, the water volume is adjusted, and water or water containing cellulose is sprayed on the surface when the sagger moves toward the kiln, so as to ensure that the powder is not lost by the exhaust smoke when entering the negative pressure area of ​​the front exhaust of the kiln (see Figure 8 ).

[0089] The firing process is energy-saving and consumption-reducing, and the formula is designed for low-temperature fast firing. In order to fully utilize the waste heat of the kiln, the mesh belt dryer is integrated with the kiln and placed above the kiln firing area. For this purpose, the traditional design of the kiln needs to be adapted and changed. The kiln exhaust gas is divided into two pipes to supply heat to the dryer on both sides, and the waste heat from the kiln cooling is divided into two pipes to supply heat on both sides. The kiln combustion air duct 9-1 is changed from the traditional central single pipe layout to a double-pipe layout on both sides, freeing up the central position for the blanking collection belt, while reducing the support height of the mesh belt dryer (see Fig. 9 ). The kiln unloading and ferrying system 2-6 is designed according to the existing design without any change.

[0090] The foamed ceramic plate is directly fired after the powder is filled into the sagger. At present, the bottom whole plate structure adopted can only be sintered from top to bottom. For this reason, the present invention adopts the method of punching holes on the bottom plate of the sagger (see Fig.10) to sinter the bottom first, and then gradually move upward, which is a measure that is more conducive to oxidation exhaust. At the same time, in order to strengthen the heat exchange of powder sintering in the sagger body, the side plate of the sagger (see Fig.11 ) are also punched according to the base plate style requirements.

[0091] Because there is a high-temperature fiber anti-sticking board between the bottom plate and the powder, the powder will not be affected after drilling. At the same time, if the hole is too large, there will be problems with the powder flowing and the strength of the ceramic plate, so the hole diameter should not be too large. After comprehensive consideration, the ceramic plate thickness is 12mm, the hole diameter is ∮5mm, the margin is 5mm, the hole center distance is 10mm, and the long plate is used for splicing.

[0092] The side panels, bottom panels and inclined support panels are not punched, and the remaining parts are evenly punched with holes of ∮5mm and a hole center distance of 10mm to facilitate side heating and cooling.

[0093] If the existing firing process curve is used to produce foamed ceramics by directly using powdered fine powder without granulation, the premature oxidation and sintering of the surface layer will be aggravated, resulting in poor exhaust, and large bubbles will be more likely to appear in the sintering under the condition of granulation. For this reason, it is necessary to make a major adjustment to the firing process curve. The specific approach is: the surface temperature gun of the oxidation firing zone should be closed before 1000℃, resulting in a huge temperature difference between the upper and lower parts, forcing the foaming sintering oxidation to start from the bottom and gradually move upward, ensuring that the top layer is finally sintered to facilitate exhaust, and accelerate this process by appropriately adjusting the lower temperature. Thus, the purpose and result of fast burning are achieved. At the same time, the arrangement of the lower rapid cooling blowing and slow cooling exhaust is increased during cooling. When there are holes in the lower plate of the sagger, the heat will be dissipated at the same time on the upper and lower parts, which is conducive to the rapid cooling of the foaming board and avoids the damage caused by shrinkage stress cracks when the one-way cooling speed is too fast. Thus, the goal of reducing the cooling time is achieved, the kiln firing time is shortened, and the purpose of reducing energy consumption and increasing production is achieved.

[0094] The sagger is composed of four parts: side plate 12-4, bottom plate 12-3, crossbeam 12-2 and main beam 12-1. The main beam 12-1 moves on the kiln roller. In order to avoid the scrapping of the kiln roller fixed main beam due to concentrated wear, the main beam 12-1 can be increased by C and D and arranged in the center. The two beams A and B are set at one-third of the distance from the head and tail of the bottom plate. The A, C and B, D main bearing beams are moved to both sides by one beam width respectively regularly, so that the main beam load is reduced by half, and the wear will be reduced accordingly; at the same time, by moving the main beam to both sides, the wear at the same position is avoided, so that the roller wears uniformly throughout the body, thereby extending the service life of the roller and reducing production costs. The crossbeam 12-2 and the main beam 12-1 are made of silicon carbide.

[0095] The present invention provides an energy-saving production system and method for foamed ceramics using dry powder making. The pulping and granulation links are reduced, and the energy consumption problem of the powder preparation link in the existing foamed ceramic production process is saved by 100%, the comprehensive energy saving in production is more than 40%, the electricity saving is more than 30%, the water saving is more than 95%, the kiln firing cycle is shortened by more than 25%, and the carbon dioxide emission is reduced by more than 40%. The problems of homogenization of foaming agent powder, impurity removal of powder, anti-sticking of cloth and loss of powder in kiln sagger in dry powder making are solved. An integrated design of a mesh belt dryer and a kiln for drying the formula material using the waste heat of the kiln is designed. The moisture content of the raw materials entering the vertical mill is reduced, and the output of the vertical mill is increased. The design of the vertical mill peak-avoiding power saving configuration can reduce the cost by more than 30%. The operating parameters and design specifications of the equipment in each process are formulated. The process flow is simplified, the equipment investment and infrastructure investment are reduced, and the foamed ceramic production is more in line with the hardware process requirements of the whole factory automation and intelligent control.

[0096] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A production system of foamed ceramics using dry powder making, characterized in that: The production system includes: mesh belt dryer and kiln integrated structure, vertical mill, atomizing surface fixing device, sagger, formula material input device, online automatic batching system, foaming agent storage bin, foaming agent feeding belt, storage bin, storage bin feeding belt, finished powder homogenizing bin, dust collector, air flow and elevator. The formula material is dried by the mesh belt dryer and then enters the vertical mill. The mesh belt dryer and kiln integrated structure comprises: Support columns, used to fix the mesh belt dryer above the kiln firing area; Mesh belt dryer, the number of mesh belt layers is an even number not less than 2, the mesh belt is arranged in sections and equipped with a transmission device; the bottom of the mesh belt dryer is a cone structure, a straight hole is arranged in the middle, and a blanking cleaning belt is installed at the lower end of the straight hole; The mesh belt dryer heating pipeline is arranged on both sides of the kiln, including a smoke exhaust waste heat utilization pipeline and a cooling waste heat utilization pipeline; the smoke exhaust waste heat utilization pipeline is connected to the kiln dehumidification and smoke exhaust system to supply heat to the front of the mesh belt dryer; the cooling waste heat utilization pipeline is connected to the kiln cooling heat extraction system to supply heat to the rear of the mesh belt dryer; The mesh belt dryer smoke exhaust device includes a heat collecting hood and a duct exhaust fan installed on the top of the mesh belt dryer, and the exhaust gas is discharged for environmental protection; The mesh belt dryer cooling waste heat exhaust port is set in the middle of the top of the mesh belt dryer and is a long row of heat dissipation holes; The kiln combustion air duct is a double-sided double-tube structure, freeing up the center for the material collection belt and reducing the support height of the mesh belt dryer. The vertical mill is a steel slag mill using tire rollers; The atomizing surface fixing device comprises an atomizer, and when the foamed ceramic sagger filled with powder moves forward, the atomizer is turned on to spray water or water liquid containing cellulose on the surface of the powder in the sagger; The sagger comprises side plates, a bottom plate, a crossbeam and a main beam; The side plates and the bottom plate are both provided with hole structures, but the side plates, the bottom plate and the inclined bearing plate are not provided with hole structures; There are four main beams, two of which are close to the center, and the other two are set at one-third of the distance from the head and tail of the bottom plate; the main beams move on the kiln rollers; The formula material input device is used to evenly spread the formula material on the uppermost belt net, move it along the kiln transmission direction, and drop it to the lower belt net after reaching the end and move in the opposite direction for drying; The foaming agent feeding belt and the storage bin feeding belt are synchronously mixed and fed to the vertical mill; After the qualified powder is ground by the vertical mill, the fine powder is collected by the dust collector and then transported to the finished powder homogenization bin for storage through air flow and elevator; The bottom of the finished powder homogenizing bin has five air flow channels evenly distributed in a fan shape, which are gathered at the discharge port to output the powder; The production system does not include a granulation system for powder materials.

2. The production system according to claim 1, characterized in that: The production system also includes a secondary impurity removal system, including a double flat screen or a single screen, and a high square screen, to remove impurities from the powder output from the finished powder homogenization bin; And / or, the production system further comprises a material supply and filling gate system, comprising a material supply bin, a material supply hopper and a material supply hopper moving device.

3. The production system according to claim 2, characterized in that: The material distribution bin is a rectangular bin with a cone structure at the bottom and is equipped with a material discharge gate; The material distribution hopper has an upper inverted cone material receiving and a lower straight-through material discharging structure. After it is filled with powder material, the lower gate is opened and the material is discharging longitudinally to the sagger.

4. The production system according to claim 2 or 3, characterized in that: The lower cone of the material bunker and the inner wall of the material hopper are sprayed with Teflon anti-stick coating.

5. A method for producing foamed ceramics by dry powdering, characterized in that: The production method comprises using the production system according to any one of claims 1 to 4; The production method comprises the following steps: The mesh belt dryer is integrated with the kiln. The mesh belt dryer is placed above the kiln firing area. The waste heat from the kiln exhaust is used to heat the front of the belt dryer, and the waste heat from the kiln cooling is used to heat the rear of the mesh belt dryer. Atomized water solidification, that is, after the powder is arranged in the sagger, the water volume is adjusted, and water or water liquid containing cellulose is sprayed on the surface when the sagger moves toward the kiln; The bottom plate of the sagger is punched with holes, the bottom is sintered first, and then gradually moves upwards; at the same time, in order to enhance the heat exchange of powder sintering in the bowl, the side plates of the sagger are also punched with holes.

6. The production method according to claim 5, characterized in that The production method also includes: vertical mill avoids peak and valley electricity production, that is, arranging batching and drying along with the kiln to produce and dry the formulated materials 24 hours a day, and during the peak electricity consumption, the vertical mill is not started, and the dried materials are stored in a peak-avoiding storage bin.

7. The production method according to claim 5 or 6, characterized in that: The production method also includes: before 1000°C, the surface temperature gun of the oxidation sintering zone should be closed and no heat should be supplied, resulting in a huge temperature difference between the upper and lower parts, forcing the foaming sintering oxidation to start from the bottom and gradually move upward to ensure that the top layer is sintered last, and appropriately increase the lower temperature to accelerate this process; at the same time, increase the arrangement of the lower rapid cooling blowing and slow cooling exhaust during cooling.

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