Method for improving air permeability of sintered thick material layer

Abstract

The invention relates to the technical field of ferrous metallurgy, in particular to a method for improving the air permeability of a sintered thick bed, which comprises the following steps: primary bedding: paving screened finished ore on a sintering trolley; secondary bedding: n rows of feeding pipes are equidistantly distributed in the transverse direction of the trolley, m feeding pipes are equidistantly distributed in each row, the tail section of the sintering machine is detected and imaged through the tail infrared thermal imager of the sintering machine, image processing is carried out through machine vision, transverse gridding and longitudinal gridding are carried out on the tail section of the sintering machine, the tail section of the sintering machine is divided into m areas in the transverse direction, and the tail section of the sintering machine is subjected to secondary bedding; extracting a red fire area to obtain the average thickness of a red fire layer; according to the average thickness, the discharging amount and speed of the feeding pipe are adjusted, and secondary bedding is conducted through the feeding pipe; and paving a sintering mixture on the basis of the secondary grate-layer material, and performing ignition sintering. And by combining the shape of a red fire layer of the tail section of the sintering machine, the blanking amount and speed of the feeding pipe are adjusted, the secondary grate-layer material distribution is optimized, and the overall material layer air permeability of the sintering pallet is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel metallurgy, in particular to a method for improving the permeability of a thick sintering material layer. BACKGROUND

[0002] In the sintering process, the permeability of the sintering mixture is a key production parameter. The permeability has a very important influence on the sintering yield and quality. When the permeability is good, the vertical speed of the sintering material layer is accelerated, thereby increasing the yield; on the contrary, poor permeability will slow down the vertical speed of the sintering material layer, which will accordingly reduce the yield per unit time. Moreover, good permeability helps to avoid the occurrence of overburning, thereby fully guaranteeing the quality of the sintered product. As can be seen, ensuring that the permeability of the mixture during sintering is within an appropriate range plays a crucial role in improving the quality of the sinter.

[0003] At present, a loosening device is generally used in the sintering production process to improve the permeability of the sintering material layer. However, with the gradual increase in the thickness of the sintering material layer, increasing the number of loosening rods in order to further improve the permeability brings a series of new problems. The gaps between the loosening rods decrease due to the increase in the number of the rods, which makes the larger pieces of sintering mixture easily get stuck between the loosening rods when passing through, and also increases the difficulty of the operators in cleaning the accumulated material of the loosening rods, and can also cause adverse phenomena such as draw grooves and unevenness on the material surface, ultimately resulting in uneven effective air volume through the material layer.

[0004] When this situation is reflected in the cross section of the sintering machine tail, it can be found that the red ore layer of the cross section has a "flower face" phenomenon, i.e., a part of the area is not burned through and contains raw material, while another part of the area is overburned, which undoubtedly seriously affects the stability of the sinter production quality. Especially in the case of a large sintering machine with a material layer thickness generally reaching 750 mm or even 1000 mm in some cases, and a large proportion of concentrate sintering, the existing loosening device is difficult to meet the requirements of the permeability of the thick material layer production. SUMMARY

[0005] In order to overcome the defects of the prior art, the technical problem solved by the present application is to provide a method for improving the permeability of a thick sintering material layer. The method comprises the following steps: distributing n rows of feeding pipes along the transverse direction of the sintering machine between the bottom material leveling plate and the nine-roller distributor, distributing m feeding pipes in each row at equal intervals, and adjusting the discharging speed of the feeding pipes in combination with the shape of the red fire layer of the cross section of the sintering machine tail, thereby optimizing the distribution of the secondary bottom material and improving the permeability of the overall material layer of the sintering trolley.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A method for improving the permeability of a thick sintering material layer, characterized in that it comprises the following steps:

[0008] 1) One-time bottom material laying: the screened finished ore is laid on the sintering trolley and scraped flat;

[0009] 2) Secondary laying of base material: On the sintering machine, n rows of feeding tubes are equidistantly distributed along the transverse direction of the trolley, with m feeding tubes equidistantly distributed in each row. The cross section of the sintering machine tail is detected and imaged by an infrared thermal imager at the sintering machine tail. The cross section of the sintering machine tail is gridded horizontally and vertically by machine vision image processing. The transverse direction is divided into m areas, and the areas are numbered, with i representing a certain area, and the value range of i is 1, 2, 3...m. Each area corresponds to the position of the feeding tube one by one, and the image processing of the red-hot area is extracted. According to the temperature distribution shape of the red-hot layer in the cross section of the sintering machine tail, the temperature characteristic value of the red-hot layer is extracted, and the edge curve function f1 of the lower layer of the red-hot layer and the edge curve function f2 of the upper layer of the red-hot layer are obtained. The average thickness of the red-hot layer in each regional grid in the transverse direction of the sintering trolley tail is obtained as h=f2-f1. The feeding rate of the feeding tube is adjusted according to the average thickness h in the regional grid. The secondary laying of base material is performed on the primary laying through the feeding tube.

[0010] 3) Laying the sintering mixture: Lay the sintering mixture on the basis of the secondary base material, level it, and ignite and sinter it.

[0011] If h < 50 mm appears continuously on three or more trolleys or three h < 50 mm appear alternately on six trolleys in the i-th area grid, the unloading speed φ of the i-th unloading pipe in each row is 0;

[0012] If the situation of 50mm≤h≤100mm appears continuously on three or more trolleys in the sintering machine within the i-th area grid, or 3 situations of 50mm≤h≤100mm appear alternately on six trolleys, the corresponding unloading speed φ of the i-th unloading pipe in each row is 30±3kg / h;

[0013] If h>100mm appears continuously on two or more trolleys in the sintering machine within the i-th area grid, or h>100mm appears alternately on two trolleys, the corresponding unloading speed φ of the i-th unloading pipe in each row is 50±5kg / h.

[0014] In the step 1), the particle size of the finished ore is 10-20 mm, and the thickness of the base material is 10-30 mm.

[0015] In the step 1), the paving material is paved on the sintering trolley through the hopper and the distributor, and the paving material is scraped flat by the paving material scraping plate.

[0016] In the step 2), 1≤n≤3, 10≤m≤30.

[0017] In the step 3), the ignition and sintering conditions are: an ignition temperature range of 950-1050° C., an exhaust negative pressure range of 8000-10500 Pa, and an ignition time range of 1.5-2 minutes.

[0018] In the step 2), a feeding pipe is arranged between the scraper plate for laying the bottom material of the sintering machine and the nine-roller distributor.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention distributes n rows of feed pipes at equal distances along the transverse direction of the trolley in the sintering machine, with m feed pipes distributed at equal distances in each row. The average thickness of the red-hot layer in each grid area in the transverse direction of the sintering trolley tail is obtained in combination with the shape of the red-hot layer in the cross-section of the sintering machine tail. The feeding speed of the feed pipe is adjusted according to the average thickness, which can change the stacking thickness and distribution of the secondary base material. That is, reducing the feeding speed can make the material layer in the area appropriately thinner, increase the porosity inside the material layer, and thus improve the air permeability. On the contrary, if the air permeability is too good, the feeding speed can be appropriately increased to thicken the material layer, so that the gas has a more appropriate flow resistance in the material layer, thereby optimizing the air permeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 It is a schematic diagram of the arrangement of the feeding pipe of the present invention.

[0023] Figure 2 It is a flow chart of the present invention.

[0024] Description of reference numerals:

[0025] In the figure: 1-trolley; 2-nine-roller distributor; 3-base material scraper; 4-feeding pipe; 5-infrared thermal imager. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are further described below:

[0027] Example 1:

[0028] Take a sintering plant 265m 2 The application of sintering machine is used as an example.

[0029] Table 1 Basic parameters of sintering machine

[0030] <![CDATA[烧结机面积 / m 2 ]]> Trolley width / mm Material layer thickness / mm 265 3500 750

[0031] like Figures 1 to 2As shown, a method for improving the permeability of a sintered thick material layer comprises the following steps:

[0032] 1) Primary bottom material laying: the finished ore with a particle size of 10-20 mm is paved onto the sintering trolley through the hopper and the distributor, and the bottom material is scraped flat by the bottom material scraper to make it smooth. The thickness of the bottom material laid in one time is 10 mm.

[0033] 2) Secondary bed material laying: n rows of feed pipes 4 are distributed equidistantly along the transverse direction of the trolley 1 between the sintering machine's bed material scraper 3 and the nine-roller distributor 2. Each row has m feed pipes 4 equidistantly spaced, with n=1 and m=10. An infrared thermal imager 5 at the sintering machine's tail section is used to image the sintering machine's tail section. Dark areas represent sintered ore that has cooled to a certain temperature, while the lower red area represents uncooled sintered ore (the red fire layer referred to in this application). The image is transmitted to an image processing interface, where machine vision is used to perform image processing. The cross-section of the sintering machine's tail section is gridded horizontally and vertically, divided horizontally into 10 regions. These regions are numbered, with i representing a specific region, and the value of i ranging from 1, 2, 3, ..., 10. Each area corresponds to the position of the feeding pipe 4 one by one, and the image processing of the red-hot area is extracted. According to the temperature distribution shape of the red-hot layer in the cross section of the sintering machine tail, the temperature characteristic value of the red-hot layer is extracted to obtain the edge curve function f1 of the lower layer of the red-hot layer and the edge curve function f2 of the upper layer of the red-hot layer. f2 is a function with the midpoint of the horizontal width of the sintering trolley as the origin, the width as the horizontal coordinate x, and the 500°C isotherm of the upper layer of the red-hot layer corresponding to the height vertical coordinate f2 from the bottom of the trolley; f1 is also a function with the midpoint of the horizontal width of the sintering trolley as the origin, the width as the horizontal coordinate x, and the 700°C isotherm of the lower layer of the red-hot layer corresponding to the height vertical coordinate f1 from the bottom of the trolley; the average thickness of the red-hot layer in each regional grid in the horizontal direction of the sintering trolley tail is h=f2-f1; the feeding speed of the feeding pipe is adjusted according to the size of the average thickness h in the regional grid; the secondary base material is laid on the primary base material through the feeding pipe;

[0034] 3) Laying the sintering mixture: Lay the sintering mixture on the basis of the secondary base material, level it, and then ignite and sinter it; the ignition and sintering conditions are: ignition temperature of 950℃, exhaust negative pressure of 8500Pa, and ignition time of 1.5min.

[0035] During the application process, if the average thickness of the red fire layer in the third area grid appears for three or more consecutive times on the sintering machine 3,1 =43.45mm, h 3,2 =33.16mm, h 3,3 =43.45mm or the intervals between the 6 trolleys appear alternately h 3,1 =41.26mm, h 3,2 =51.38mm, h 3,3=33.68mm, h 3,4 =56.87mm, h 3,5 =23.76mm, h 3,6 =63.45mm, the corresponding unloading speed of the third unloading pipe is φ0; (where h 3,1 、h 3,2 、h 3,3 It represents the average thickness of the red fire layer of three consecutive trolleys in the third area grid, and the same applies below).

[0036] If the average thickness of the red fire layer in the 5th area grid appears for 3 or more consecutive times on the sintering machine 5,1 =81.36mm, h 5,2 =72.45mm, h 5,3 =91.05mm or the intervals between the 6 trolleys appear alternately h 5,1 =41.26mm, h 5,2 =51.38mm, h 5,3 =33.68mm, h 5,4 =56.87mm, h 5,5 =23.76mm, h 5,6 =63.45mm, corresponding to the unloading speed of the 5th unloading pipe φ is 31kg / h;

[0037] If the average thickness of the red fire layer in the grid of the 6th area appears for h on 2 or more trolleys on the sintering machine 6,1 =121.44mm, h 6,2 =109.36mm or the four pallets appear alternately at intervals h 6,1 =96.66mm,h 6,2 =129.38mm, h 6,3 =91.48mm, h 6,4 =152.26mm, corresponding to the unloading speed φ of the 6th unloading pipe is 55kg / h.

[0038] In this embodiment, the vertical speed of the sintering machine is increased from 24.44 mm / min to 28.66 mm / min and the utilization coefficient is increased from 1.28 t / (m 2 h) increased to 1.38t / (m 2 h), an increase of 8 percentage points; the sinter drum strength increased from 78.76% to 80.03%; and the screening index decreased from 6.80% to 6.53%.

[0039] Example 2:

[0040] Take a sintering plant with a height of 360m 2 The application of sintering machine is used as an example.

[0041] Table 2 Basic parameters of sintering machine

[0042]

[0043] A method for improving the air permeability of a sintered thick material layer comprises the following steps:

[0044] 1) Primary bottom material laying: the finished ore with a particle size of 10-20 mm is paved onto the sintering trolley through the hopper and the distributor, and the bottom material is scraped flat by the bottom material scraper to make it smooth. The thickness of the bottom material laid in one time is 15 mm.

[0045] 2) Secondary base material laying: n rows of feeding pipes are evenly spaced along the transverse direction of the trolley between the base material laying scraper plate and the nine-roller distributor. Each row has m feeding pipes evenly spaced, where n = 2 and m = 20. The cross section of the sintering machine tail is detected and imaged by an infrared thermal imager at the sintering machine tail. The image is transmitted to the image processing interface, and machine vision is used to perform image processing on the cross section of the sintering machine tail, gridding it horizontally and vertically. The cross section is divided into 20 areas in the transverse direction and numbered. i is set to represent a certain area, and the value of i ranges from 1, 2, 3…20. Each area corresponds to the position of the feeding tube one by one, and the image processing of the red-fire area is extracted. According to the temperature distribution shape of the red-fire layer in the cross section of the sintering machine tail, the temperature characteristic value of the red-fire layer is extracted to obtain the edge curve function f1 of the lower layer of the red-fire layer and the edge curve function f2 of the upper layer of the red-fire layer. f2 is a function of the midpoint of the horizontal width of the sintering trolley as the origin, the width as the horizontal coordinate x, and the 500℃ isotherm of the upper layer of the red-fire layer corresponding to the height vertical coordinate f2 from the bottom of the trolley; f1 is also a function of the midpoint of the horizontal width of the sintering trolley as the origin, the width as the horizontal coordinate x, and the 700℃ isotherm of the lower layer of the red-fire layer corresponding to the height vertical coordinate f1 from the bottom of the trolley; the average thickness of the red-fire layer in each regional grid in the horizontal direction of the sintering trolley tail is h=f2-f1; the feeding speed of the feeding tube is adjusted according to the size of the average thickness h in the regional grid. The secondary base material is laid on the primary base material through the feeding tube;

[0046] 3) Laying the sintering mixture: Lay the sintering mixture on the basis of the secondary base material, level it, and ignite and sinter it; the ignition and sintering conditions are: ignition temperature of 1047.9℃, exhaust negative pressure of 8980Pa, and ignition time of 1.67min.

[0047] During the application process, if the average thickness of the red fire layer in the grid of the 7th area appears for 3 or more consecutive times on the sintering machine 7,1 =24.35mm, h 7,2 =13.56mm, h 7,3 =23.65mm or the intervals between the 6 trolleys appear alternately h 7,1 =11.27mm, h7,2 = 61.38 mm, h 7,3 = 23.69 mm, h 7,4 = 66.18 mm, h 7,5 = 43.68 mm, h 7,6 = 73.45 mm, the corresponding φ of the 7th downcomer in the 2nd row is 0;

[0048] If the average thickness of the red flame layer in the 9th grid appears continuously for 3 or more cars on the sintering machine h 9,1 = 90.48 mm, h 9,2 = 88.46 mm, h 9,3 = 99.95 mm, or h 9,1 = 31.36 mm, h 9,2 = 72.39 mm, h 9,3 = 43.98 mm, h 9,4 = 81.67 mm, h 9,5 = 33.31 mm, h 9,6 = 53.55 mm, the corresponding φ of the 9th downcomer in the 2nd row is 33 kg / h;

[0049] If the average thickness of the red flame layer in the 13th grid appears continuously for 2 or more cars on the sintering machine h 13,1 = 106.54 mm, h 13,2 = 119.46 mm, or h 13,1 = 88.66 mm, h 13,2 = 141.18 mm, h 13,3 = 75.59 mm, h 13,4 = 132.33 mm, the corresponding φ of the 13th downcomer in the 2nd row is 53 kg / h.

[0050] The vertical speed of the sintering machine in this embodiment is increased from 25.46 mm / min to 29.16 mm / min, the utilization coefficient is increased from 1.29 t / (m 2 ·h) to 1.41 t / (m 2 ·h), an increase of 9 percentage points; the sinter drum strength is increased from 79.76% to 81.03%; the screening index is reduced from 5.90% to 5.73%.

[0051] Example 3:

[0052] Take a 405 m 2 sintering machine as an example.

[0053] Table 3 Basic parameters of sintering machine

[0054]

[0055] A method for improving the permeability of a sintering thick layer, comprising the following steps:

[0056] 1) First bottoming material: the screened finished product with a particle size of 10-20 mm is laid on the sintering trolley through the bunker and the distributor, and the first bottoming material is leveled by the bottoming material leveling plate, so that it is flat, and the thickness of the first bottoming material ranges from 15 mm;

[0057] 2) Second bottoming material: n rows of feeding pipes are distributed at equal intervals along the transverse direction of the trolley between the bottoming material leveling plate of the sintering machine and the nine-roller distributor, and each row has m feeding pipes, n=3, m=30; the sintering machine tail section is detected and imaged by the infrared thermal imager at the sintering machine tail, the image is transmitted to the image processing interface, the image processing is performed by machine vision to horizontally and vertically grid the sintering machine tail section, the horizontal direction is divided into 30 areas, and the areas are numbered, and i represents a certain area, i takes a value ranging from 1, 2, 3…30. Each area corresponds to the position of a feeding pipe, the image processing of the red fire area is extracted, the temperature characteristic value of the red fire layer is extracted according to the temperature distribution shape of the red fire layer of the sintering machine tail section, the lower edge curve function f1 of the red fire layer and the upper edge curve function f2 of the red fire layer are obtained, f2 is a function of the midpoint of the transverse width of the sintering trolley as the origin, the width as the horizontal coordinate x, and the height of the 500℃ isotherm of the upper layer of the red fire layer corresponding to the distance from the bottom of the trolley as the vertical coordinate f2; f1 is also a function of the midpoint of the transverse width of the sintering trolley as the origin, the width as the horizontal coordinate x, and the height of the 700℃ isotherm of the lower layer of the red fire layer corresponding to the distance from the bottom of the trolley as the vertical coordinate f1; the average thickness of the red fire layer in each area grid at the tail of the sintering trolley is h=f2-f1; the feeding amount of the feeding pipe is adjusted according to the average thickness h in the area grid; the second bottoming material is laid on the first bottoming material through the feeding pipe;

[0058] 3) Laying sintering mixture: laying sintering mixture on the basis of the second bottoming material and leveling, igniting and sintering; the ignition sintering conditions are: the ignition temperature is 1046.8℃, the exhaust negative pressure is 9680Pa, and the ignition time is 1.97min.

[0059] In the application process, if the average thickness of the red fire layer in the 9th area grid continuously appears h 9,1 =33.45mm, h 9,2 =24.66mm, h 9,3 =43.66mm on 3 trolleys or more of the sintering machine, or h 9,1 =41.28mm, h 9,2 =67.39mm, h 9,3= 34.66 mm, h 9,4 = 56.17 mm, h 9,5 = 34.55 mm, h 9,6 = 63.46 mm, the corresponding φ of the 9th pipe in the 3rd row is 0;

[0060] If the average thickness of the red flame layer in the 12th grid appears continuously for 3 or more cars on the sintering machine, h 12,1 = 76.49 mm, h 12,2 = 78.56 mm, h 12,3 = 89.45 mm, or h 12,1 = 43.37 mm, h 12,2 = 62.49 mm, h 12,3 = 33.88 mm, h 12,4 = 71.27 mm, h 12,5 = 43.36 mm, h 12,6 = 73.56 mm, the corresponding φ of the 12th pipe in the 3rd row is 32 kg / h;

[0061] If the average thickness of the red flame layer in the 16th grid appears continuously for 2 or more cars on the sintering machine, h 16,1 = 123.55 mm, h 16,2 = 149.16 mm, or h 16,1 = 58.76 mm, h 16,2 = 131.56 mm, h 16,3 = 65.59 mm, h 16,4 = 102.53 mm, the corresponding φ of the 16th pipe in the 3rd row is 51 kg / h.

[0062] The vertical speed of the sintering machine in this embodiment is increased from 27.46 mm / min to 31.16 mm / min, the utilization coefficient is increased from 1.31 t / (m 2 ·h) to 1.46 t / (m 2 ·h), an increase of 11.4 percentage points; the sinter drum strength is increased from 79.76% to 82.03%; the screening index is reduced from 5.40% to 5.03%.

[0063] The preferred embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all fall within the scope of protection of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner unless there is any contradiction. In order to avoid unnecessary repetition, the present invention will no longer describe various possible combinations separately. In addition, the various different embodiments of the present invention can also be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for improving the permeability of a thick sintered material layer, characterized in that: The steps include: 1) One-time bottom material laying: the screened finished ore is laid on the sintering trolley and scraped flat; 2) Secondary laying of base material: On the sintering machine, n rows of feeding tubes are equidistantly distributed along the transverse direction of the trolley, with m feeding tubes equidistantly distributed in each row. The cross section of the sintering machine tail is detected and imaged by an infrared thermal imager at the sintering machine tail. The cross section of the sintering machine tail is gridded horizontally and vertically by machine vision image processing. The transverse direction is divided into m areas, and the areas are numbered, with i representing a certain area, and the value range of i is 1, 2, 3...m. Each area corresponds to the position of the feeding tube one by one, and the image processing of the red-hot area is extracted. According to the temperature distribution shape of the red-hot layer in the cross section of the sintering machine tail, the temperature characteristic value of the red-hot layer is extracted, and the edge curve function f1 of the lower layer of the red-hot layer and the edge curve function f2 of the upper layer of the red-hot layer are obtained. The average thickness of the red-hot layer in each regional grid in the transverse direction of the sintering trolley tail is obtained as h=f2-f1. The feeding rate of the feeding tube is adjusted according to the average thickness h in the regional grid. The secondary laying of base material is performed on the primary laying through the feeding tube. 3) Laying the sintering mixture: Lay the sintering mixture on the basis of the secondary base material, level it, and ignite and sinter it.

2. A method for improving the air permeability of a sintered thick material layer according to claim 1, characterized in that: If h < 50 mm appears continuously on three or more trolleys or three h < 50 mm appear alternately on six trolleys in the i-th area grid, the unloading speed φ of the i-th unloading pipe in each row is 0; If the situation of 50mm≤h≤100mm appears continuously on three or more trolleys in the sintering machine within the i-th area grid, or 3 situations of 50mm≤h≤100mm appear alternately on six trolleys, the corresponding unloading speed φ of the i-th unloading pipe in each row is 30±3kg / h; If h>100mm appears continuously on two or more trolleys in the sintering machine within the i-th area grid, or h>100mm appears alternately on two trolleys, the corresponding unloading speed φ of the i-th unloading pipe in each row is 50±5kg / h.

3. The method for improving the air permeability of a sintered thick material layer according to claim 1, characterized in that: In the step 1), the particle size of the finished ore is 10-20 mm, and the thickness of the base material is 10-30 mm.

4. The method for improving the air permeability of a thick sintered material layer according to claim 1, characterized in that: In the step 1), the paving material is paved on the sintering trolley through the hopper and the distributor, and the paving material is scraped flat by the paving material scraping plate.

5. The method for improving the air permeability of a sintered thick material layer according to claim 1, characterized in that: In the step 2), 1≤n≤3, 10≤m≤30.

6. The method for improving the air permeability of a thick sintered material layer according to claim 1, characterized in that: In the step 2), a feeding pipe is arranged between the scraper plate for laying the bottom material of the sintering machine and the nine-roller distributor.

7. The method for improving the air permeability of a thick sintered material layer according to claim 1, characterized in that: In the step 3), the ignition and sintering conditions are: an ignition temperature range of 950-1050° C., an exhaust negative pressure range of 8000-10500 Pa, and an ignition time range of 1.5-2 minutes.

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