Top structure of full-pouring composite coke oven

Abstract

The invention discloses a full-pouring composite coke oven top structure which comprises an upper layer high-strength structure and a lower layer heat insulation structure, the lower layer heat insulation structure is formed by pouring heat insulation castable, and the upper layer high-strength structure is formed by pouring high-performance castable. The overall stability of the full-pouring furnace top is achieved, meanwhile, due to the fact that refractory castable made of different materials is poured in a layered mode, the risk that through seams are formed due to cracking of refractory materials is greatly reduced, the surface temperature of the furnace top is reduced to 190 DEG C from 230 DEG C through the heat-insulation high-strength castable on the bottom layer, the thermal efficiency of a coke oven is improved, and during production and application, the production cost is reduced. The method has positive significance on long-life management of the coke oven, efficient production, cost reduction, efficiency improvement, safety, environmental protection, and promotion of sustainable development and health of employees.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a fully cast composite coke oven roof structure. Background Art

[0002] Coke ovens are important equipment in the metallurgical industry, used to produce coke. With the continuous advancement of industrialization, high-temperature equipment such as coke ovens play a vital role in the production of the steel industry. The coke oven roof is an important part of maintaining the normal operation of the coke oven and ensuring safe production. The temperature of the coke oven roof can often reach 1000-1200℃. The coke oven roof is subjected to high temperature, corrosion and mechanical stress. In addition, due to the long-term high temperature and high thermal stress on the coke oven roof, the roof material will be severely damaged and worn, resulting in a shortened service life of the coke oven roof, and even damage to the roof.

[0003] The roof of the coke oven is an open-air operation, exposed to the sun and rain for a long time. The roof of the coke oven operates in an environment with drastic temperature changes and is eroded by rain for a long time. The brick masonry of the coal loading hole is subjected to the vibration of the coal loading car and the frequent opening of the cover during the coal loading process, which causes the refractory material to cool and heat rapidly and the friction of the coal loading hole cover, resulting in the following problems on the roof surface: 1) The mud in the seam of the coal loading hole bricks is easy to loosen, causing fire, smoke and fracture of the coal loading hole bricks, resulting in serious carburization of the coal loading hole seat bricks and the coal loading hole seat, which eventually leads to the protrusion and displacement of the coal loading hole, and the coal loading hole bricks are frequently replaced; 2) The mud powder in the seam of the furnace roof bricks causes empty seams, causing the fire viewing hole bricks to crack due to thermal expansion and contraction, and even rainwater enters the combustion chamber, which not only damages the refractory material, but also affects the heating quality, resulting in increased fuel consumption and difficulty in pushing coke; 3) The clay seat bricks of the riser are easily broken by rainwater, and rainwater seeps into the interior of the furnace roof, causing smoke and fire, and even burning the upper cross brace. Due to the protruding displacement of the coal loading port, leakage of the furnace roof masonry and the root of the riser, the overflow of smoke and raw coal gas causes a large amount of unorganized emissions, which seriously affects the on-site working environment, the health of employees, the longevity of the coke oven and safe production.

[0004] Especially in areas with abundant rainfall and frequent tropical storms and typhoons, there are prone to strong winds and rainstorms, with concentrated rainfall, heavy rain and long duration, and relatively small evaporation from the furnace roof, which often causes large-scale and long-term water accumulation on the coke oven roof. At the same time, the furnace roof is uneven and the drainage effect is poor. During rainstorms, water accumulates significantly on the furnace roof, causing cracking and powdering of the refractory materials and brick joints on the furnace roof. Rainwater leaks into the furnace from the brick joints on the furnace roof or the fire-viewing hole cover along the vertical fire channel. A large amount of rainwater leaks into the furnace body, exacerbating the window leakage of the furnace body. In severe cases, rainwater even seeps out from the bottom of the coke oven, causing damage to the refractory materials inside the coke oven body, leakage of the coke oven body, blockage of the inclined road opening and lattice brick airflow channels, unstable pressure in the furnace, and serious fire and smoke from the furnace body. For example, since the coking unit 1 and 2 coke ovens of Zhanjiang Iron and Steel Plant were put into operation, a large number of inclined channels were blocked due to water inlet to the fire channel, or leakage of the main single wall of the exhaust gas tray, the sealing wall and partition wall of the heat storage chamber, and the brick gas channel, resulting in the failure of normal supply of gas or air, causing the fire channel temperature to be low or even some fire channels to lose their heating function. According to statistics, there are 53 serious fire channels in the four furnaces, accounting for 0.56% of the total. This leads to uneven heating of the furnace body and reduced coke quality, which is a major hidden danger affecting the safe production and longevity of the coke oven.

[0005] The roof of domestic coke ovens generally adopts brickwork structure. The roof brickwork is a two-layer structure. The bottom layer is made of clay bricks, and the surface layer is made of cylinder bricks (semi-silicon bricks). The roof surface forms a certain slope from the center to facilitate drainage of the roof area. The roof of the coke oven is an open-air operation, which is exposed to the sun and rain for a long time. The roof is operated in an environment with drastic temperature changes for a long time and is washed by rain, which will cause the fire mud in the brick joints to pulverize and peel off to form through cracks. Rainwater enters the refractory masonry of the roof through the cracks in the refractory materials and the loose parts of the roof, damaging the roof bricks, affecting the life of the coke oven, and affecting the normal maturation of the coke in the upper part of the carbonization chamber. In severe cases, it may cause the furnace wall to turn black, the fire channel to extinguish, and the coke is difficult to push out, which poses a great threat to the normal and stable production order, and also greatly increases energy consumption.

[0006] At present, relevant domestic units have conducted relevant research on coke oven roofs, such as a method for improving the air tightness of coke oven roofs and a roof structure disclosed by MCC Jiao Nai Engineering Technology Co., Ltd. (patent application number CN201110043589.X), a coke oven roof maintenance method and spraying device disclosed by Shandong Iron and Steel Co., Ltd. (patent application number CN201711307646.4), and a coke oven roof leak pneumatic spraying device and pneumatic spraying method disclosed by Xinyu Iron and Steel Co., Ltd. (patent application number CN201810 080106.5), a coke oven roof structure disclosed by MCC Jiao Nai Engineering Technology Co., Ltd. (patent application number CN201120046929.X), a cooling coke oven roof structure disclosed by Shanghai Meishan Iron and Steel Co., Ltd. (patent application number CN201220268488.2). The roof structures corresponding to the above inventions are just some improvements on the original brick roof structure, and the actual application effect is not ideal, especially for the coke oven production in areas with heavy rainfall and long duration. Summary of the invention

[0007] The purpose of the present invention is to provide a fully cast composite coke oven roof structure, which can extend the service life, reduce the heat loss of the coke oven roof, improve the thermal efficiency of the coke oven, and ensure the safety, longevity and stable production of the coke oven.

[0008] In order to achieve the above object, the present invention adopts the following technical scheme: a fully cast composite coke oven roof structure, characterized in that it comprises an upper high-strength structure and a lower heat-insulating structure; The lower insulation structure is cast by lightweight insulation castable, and the raw material components of the lightweight insulation castable are as follows: 5-7% porous lightweight mullite particles with a particle size of >5mm and <8mm, 12-15% porous lightweight mullite particles with a particle size of >3mm and <5mm, 8-10% porous lightweight mullite particles with a particle size of >1mm and <3mm, 9-9.8% alumina hollow spheres with a particle size of >1mm and <3mm, 21-23% lightweight mullite with a particle size of <1mm, 9.5-10.5% mullite fine powder, 14-16% alumina fine powder with an alumina content of 85%, 4-6% high-purity silicon powder, 7.5-8.5% binder, and water reducer. 0.2%, the sum of the mass percentages of the above components is 100%; wherein, porous lightweight mullite particles with a particle size of >5mm and <8mm, porous lightweight mullite particles with a particle size of >3mm and <5mm, porous lightweight mullite particles with a particle size of >1mm and <3mm, hollow alumina spheres with a particle size of >1mm and <3mm, and lightweight mullite with a particle size of <1mm constitute the second aggregate; synthetic mullite fine powder, alumina fine powder with an alumina content of 85% and high-purity silicon powder constitute the second fine powder; during the construction of lightweight thermal insulation castable, the second aggregate, the second fine powder, the binder and the water reducer are uniformly mixed to obtain a lightweight premix; water is added to the lightweight premix and stirred to obtain a lightweight thermal insulation castable; The upper high-strength structure is cast by heavy castables, and the raw material components of the heavy castables are as follows: 15-17% white corundum fine powder, 3.5-4.5% alumina ultrafine powder, 3.5-4.5% high-purity silicon powder, 4.8-5.3% binder, 0.2% water reducer, 0.1% organic fiber, 6-9% fused synthetic mullite with a particle size of >5mm and <8mm, 16-18% fused synthetic mullite with a particle size of >3mm and <5mm, 20-22% fused synthetic mullite with a particle size of >1mm and <3mm, 23.5-25.5% fused synthetic mullite with a particle size of <1mm, and 1.3-1.8% stainless steel heat-resistant fiber. The mass percentages of the above components are and is 100%; wherein, aggregate No. 1 is composed of fused synthetic mullite with a particle size of >5mm and <8mm, fused synthetic mullite with a particle size of >3mm and <5mm, fused synthetic mullite with a particle size of >1mm and <3mm, and fused synthetic mullite with a particle size of <1mm; fine powder No. 1 is composed of fine white corundum powder, ultrafine alumina powder, and high-purity silicon powder; when heavy castable is constructed, firstly, fine powder No. 1, binder, water reducer, and organic fiber are mixed evenly to obtain premix No. 1; then, aggregate No. 1 is added to premix No. 1 and mixed evenly to obtain premix No. 2; then, stainless steel heat-resistant fiber is added to premix No. 2 and mixed evenly to obtain premix No. 3; finally, water is added to premix No. 3 and stirred evenly to obtain heavy castable.

[0009] Furthermore, the amount of water added to the light premix for stirring is 22% of the mass of the premix.

[0010] Furthermore, the amount of water added to the No. 3 premix for stirring is 7% of the mass of the No. 3 premix.

[0011] Furthermore, the raw material components of the lightweight thermal insulation castable have the following mass percentages: 5% porous lightweight mullite particles with a particle size of >5mm and <8mm, 15% porous lightweight mullite particles with a particle size of >3mm and <5mm, 10% porous lightweight mullite particles with a particle size of >1mm and <3mm, 9.8% alumina hollow spheres with a particle size of >1mm and <3mm, 22% lightweight mullite with a particle size of <1mm, 10% mullite fine powder, 15% alumina fine powder with an alumina content of 85%, 5% high-purity silicon powder, 8% binder, and 0.2% water reducer.

[0012] Furthermore, the raw material components of the heavy castable have the following mass percentages: 16% white corundum fine powder, 4% ultrafine alumina powder, 4% high-purity silicon powder, 5.1% binder, 0.2% water reducer, 0.1% organic fiber, 8% fused synthetic mullite with a particle size >5mm and <8mm, 17% fused synthetic mullite with a particle size >3mm and <5mm, 21% fused synthetic mullite with a particle size >1mm and <3mm, 23.1% fused synthetic mullite with a particle size <1mm, and 1.5% stainless steel heat-resistant fiber.

[0013] Furthermore, the binder is high-alumina cement; and the water reducer is a naphthalene-based water reducer.

[0014] Further, the preparation method of porous lightweight mullite particles is as follows: (1) Prepare raw materials. The raw material components and mass percentages of porous lightweight mullite particles are as follows: 38-42% mullite fine powder, 15-17% silica powder, 19-21% alumina fine powder, 6-9% fly ash, 8-9% kaolin, 4.5-5.5% PP particles with a particle size of 1-5 mm, 0.8-1.1% foaming agent, and 0.1% 6 mm organic fiber; (2) Add water to the raw materials in step (1), stir evenly and press into blocks, the amount of water added is 4% of the raw material mass; (3) Sintered into blocks at 1250℃; After cooling, the particles are crushed according to the required specifications to obtain porous light mullite particles with a particle size of >5mm and <8mm, porous light mullite particles with a particle size of >3mm and <5mm, and porous light mullite particles with a particle size of >1mm and <3mm.

[0015] Furthermore, the raw material components and mass percentages of the porous lightweight mullite particles are: 40% mullite fine powder, 16% silica powder, 20% alumina fine powder, 8% fly ash, 9.9% kaolin, 5% PP particles with a particle size of 1-5 mm, 1% foaming agent, and 0.1% 6 mm organic fiber; Furthermore, after the upper high-strength structure is poured, the height difference between the center of the furnace top and the edge of the slope is 75 mm. With this design, the height difference of the slope is increased from 30 mm in the existing design to 75 mm, greatly improving the drainage efficiency.

[0016] The beneficial effects of the present invention are as follows: the present invention realizes the overall stability of the fully cast furnace roof. At the same time, due to the layered casting of castables of different materials, the risk of through-cracks formed due to cracking of refractory materials is greatly reduced. The bottom layer of insulating high-strength castable reduces the surface temperature of the furnace roof from 230°C to 190°C, thereby improving the thermal efficiency of the coke oven. When used in production, it has positive significance for the long-life management of the coke oven, efficient production, cost reduction and efficiency improvement, safety and environmental protection, and the promotion of sustainable development and the health of employees. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0018] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0019] like Figure 1 As shown, a fully cast composite coke oven roof structure of the present invention comprises an upper high-strength structure 2 and a lower heat-insulating structure 1. The lower heat-insulating structure 1 is cast by using a light heat-insulating castable; the upper high-strength structure 2 is cast by using a heavy castable. After the upper high-strength structure is cast, the height difference between the center of the furnace roof and the edge of the slope is 75 mm.

[0020] Preferably, the raw material components of the lightweight thermal insulation castable are as follows by mass percentage: 5% porous lightweight mullite particles with a particle size of >5mm and <8mm, 15% porous lightweight mullite particles with a particle size of >3mm and <5mm, 10% porous lightweight mullite particles with a particle size of >1mm and <3mm, 9.8% hollow alumina balls with a particle size of >1mm and <3mm, 22% lightweight mullite with a particle size of <1mm, 10% mullite fine powder, 15% alumina fine powder with an alumina content of 85%, 5% high-purity silicon powder, 8% binder, and 0.2% water reducer. Among them, porous lightweight mullite particles with a particle size of >5mm and <8mm, porous lightweight mullite particles with a particle size of >3mm and <5mm, porous lightweight mullite particles with a particle size of >1mm and <3mm, hollow alumina balls with a particle size of >1mm and <3mm, and lightweight mullite with a particle size of <1mm constitute the second aggregate. The second fine powder is composed of synthetic mullite fine powder, alumina fine powder with an alumina content of 85% and high-purity silicon micropowder.

[0021] During the construction of lightweight thermal insulation castable, the No. 2 aggregate, No. 2 fine powder, binder and water reducer are evenly mixed to obtain a lightweight premix; water is added to the lightweight premix and stirred evenly to obtain a lightweight thermal insulation castable; the amount of water added is 22% of the mass of the premix.

[0022] Preferably, the raw material components of the raw material of the heavy castable are as follows: 16% white corundum fine powder, 4% alumina ultrafine powder, 4% high-purity silicon powder, 5.1% binder, 0.2% water reducer, 0.1% organic fiber, 8% electrofused synthetic mullite with a particle size of >5mm and <8mm, 17% electrofused synthetic mullite with a particle size of >3mm and <5mm, 21% electrofused synthetic mullite with a particle size of >1mm and <3mm, 23.1% electrofused synthetic mullite with a particle size of <1mm, and 1.5% stainless steel heat-resistant fiber. Among them, electrofused synthetic mullite with a particle size of >5mm and <8mm, electrofused synthetic mullite with a particle size of >3mm and <5mm, electrofused synthetic mullite with a particle size of >1mm and <3mm, and electrofused synthetic mullite with a particle size of <1mm constitute the first aggregate. White corundum fine powder, alumina ultrafine powder and high-purity silicon powder constitute the first fine powder.

[0023] During the construction of heavy-weight castables, firstly mix the No. 1 fine powder, binder, water reducer and organic fiber evenly to obtain the No. 1 premix; then add the No. 1 aggregate to the No. 1 premix and mix evenly to obtain the No. 2 premix; then add the stainless steel heat-resistant fiber to the No. 2 premix and mix evenly to obtain the No. 3 premix; finally, add water to the No. 3 premix and stir evenly to obtain the heavy-weight castable; the amount of water added is 7% of the mass of the No. 3 premix.

[0024] Preferably, the binder is high-alumina cement; and the water reducer is a naphthalene-based water reducer.

[0025] Further, the preparation method of porous lightweight mullite particles is as follows: (1) Prepare raw materials. The raw material components and mass percentages are as follows: mullite fine powder 40%, silica powder 16%, alumina fine powder 20%, fly ash 8%, kaolin 9.9%, PP particles with a particle size of 1-5 mm 5%, foaming agent 1%, and 6 mm organic fiber 0.1%; (2) Add water to the raw materials in step (1), stir evenly and press into blocks, the amount of water added is 4% of the raw material mass; (3) Sintered into blocks at 1250℃; (4) After cooling, the particles are crushed according to the required specifications to obtain porous light mullite particles with a particle size of >5 mm and <8 mm, porous light mullite particles with a particle size of >3 mm and <5 mm, and porous light mullite particles with a particle size of >1 mm and <3 mm.

[0026] The construction method of the fully cast composite coke oven roof structure is as follows: (1) Comprehensively measure the top elevation of the furnace roof fire hole wall and the coal loading hole bricks. The measurement basis is the coke oven anti-wall elevation control point to determine the range of the maximum slope of the furnace roof; (2) Construction of lightweight thermal insulation castable at the bottom: Make lightweight thermal insulation castable as required. Use a vibrating rod to vibrate during the pouring process to eliminate pores and ensure the fluidity of the castable, improve the density of the castable, and control the pouring thickness at 70 mm. (3) Smoothing, curing and hardening the surface of lightweight thermal insulation castables; (4) According to the control points, the elevations of each fire hole wall on the machine focal side, machine center, and focal center shall be measured and recorded, and a line shall be drawn before pouring to form a 75mm slope standard control line; (5) Heavy castable construction: Make heavy castable as required. Use a vibrating rod to vibrate during the pouring process to eliminate pores and ensure the fluidity of the castable, thereby improving the density of the castable. Smooth the castable surface according to the standard control line of the furnace roof slope and re-measure the slope. Ensure that the height difference h between the center of the furnace roof and the slope is 75mm. This design can increase the drainage speed of the furnace roof, reduce the accumulation time of rainwater on the furnace roof, and increase the life of the fully cast composite coke oven roof; (6) Maintenance: Sprinkle water every hour to keep it moist, and maintain at room temperature for more than 24 hours; (7) Put into use.

[0027] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fully cast composite coke oven roof structure, characterized in that: It includes an upper high-strength structure and a lower thermal insulation structure; The lower insulation structure is cast by lightweight insulation castable, and the raw material components of the lightweight insulation castable are as follows: 5-7% porous lightweight mullite particles with a particle size of >5mm and <8mm, 12-15% porous lightweight mullite particles with a particle size of >3mm and <5mm, 8-10% porous lightweight mullite particles with a particle size of >1mm and <3mm, 9-9.8% alumina hollow spheres with a particle size of >1mm and <3mm, 21-23% lightweight mullite with a particle size of <1mm, 9.5-10.5% mullite fine powder, 14-16% alumina fine powder with an alumina content of 85%, 4-6% high-purity silicon powder, 7.5-8.5% binder, and water reducer. 0.2%, the sum of the mass percentages of the above components is 100%; wherein, porous lightweight mullite particles with a particle size of >5mm and <8mm, porous lightweight mullite particles with a particle size of >3mm and <5mm, porous lightweight mullite particles with a particle size of >1mm and <3mm, hollow alumina spheres with a particle size of >1mm and <3mm, and lightweight mullite with a particle size of <1mm constitute the second aggregate; synthetic mullite fine powder, alumina fine powder with an alumina content of 85% and high-purity silicon powder constitute the second fine powder; during the construction of lightweight thermal insulation castable, the second aggregate, the second fine powder, the binder and the water reducer are uniformly mixed to obtain a lightweight premix; water is added to the lightweight premix and stirred to obtain a lightweight thermal insulation castable; The upper high-strength structure is cast by heavy castables, and the raw material components of the heavy castables are as follows: 15-17% white corundum fine powder, 3.5-4.5% alumina ultrafine powder, 3.5-4.5% high-purity silicon powder, 4.8-5.3% binder, 0.2% water reducer, 0.1% organic fiber, 6-9% fused synthetic mullite with a particle size of >5mm and <8mm, 16-18% fused synthetic mullite with a particle size of >3mm and <5mm, 20-22% fused synthetic mullite with a particle size of >1mm and <3mm, 23.5-25.5% fused synthetic mullite with a particle size of <1mm, and 1.3-1.8% stainless steel heat-resistant fiber. The mass percentages of the above components are and is 100%; wherein, aggregate No. 1 is composed of fused synthetic mullite with a particle size of >5mm and <8mm, fused synthetic mullite with a particle size of >3mm and <5mm, fused synthetic mullite with a particle size of >1mm and <3mm, and fused synthetic mullite with a particle size of <1mm; fine powder No. 1 is composed of fine white corundum powder, ultrafine alumina powder, and high-purity silicon powder; when heavy castable is constructed, firstly, fine powder No. 1, binder, water reducer, and organic fiber are mixed evenly to obtain premix No. 1; then, aggregate No. 1 is added to premix No. 1 and mixed evenly to obtain premix No. 2; then, stainless steel heat-resistant fiber is added to premix No. 2 and mixed evenly to obtain premix No. 3; finally, water is added to premix No. 3 and stirred evenly to obtain heavy castable.

2. The fully cast composite coke oven roof structure according to claim 1, characterized in that: The amount of water added to the light premix for stirring is 22% of the mass of the premix.

3. The fully cast composite coke oven roof structure according to claim 1, characterized in that: The amount of water added to the No. 3 premix for stirring is 7% of the mass of the No. 3 premix.

4. The fully cast composite coke oven roof structure according to claim 1, characterized in that: The raw material components of the lightweight thermal insulation castable are as follows: 5% of porous lightweight mullite particles with a particle size of >5mm and <8mm, 15% of porous lightweight mullite particles with a particle size of >3mm and <5mm, 10% of porous lightweight mullite particles with a particle size of >1mm and <3mm, 9.8% of hollow alumina spheres with a particle size of >1mm and <3mm, 22% of lightweight mullite with a particle size of <1mm, 10% of mullite fine powder, 15% of alumina fine powder with an alumina content of 85%, 5% of high-purity silicon powder, 8% of a binder, and 0.2% of a water reducer.

5. The fully cast composite coke oven roof structure according to claim 1, characterized in that: The raw material components of the heavy castable are as follows by mass percentage: 16% white corundum fine powder, 4% alumina ultrafine powder, 4% high-purity silicon powder, 5.1% binder, 0.2% water reducer, 0.1% organic fiber, 8% fused synthetic mullite with a particle size of >5mm and <8mm, 17% fused synthetic mullite with a particle size of >3mm and <5mm, 21% fused synthetic mullite with a particle size of >1mm and <3mm, 23.1% fused synthetic mullite with a particle size of <1mm, and 1.5% stainless steel heat-resistant fiber.

6. The fully cast composite coke oven roof structure according to claim 4 or 5, characterized in that: The binder is high-alumina cement; the water reducer is a naphthalene-based water reducer.

7. The fully cast composite coke oven roof structure according to claim 1, characterized in that: The preparation method of porous lightweight mullite particles is as follows: (1) Prepare raw materials. The raw material components and mass percentages of porous lightweight mullite particles are as follows: 38-42% mullite fine powder, 15-17% silica powder, 19-21% alumina fine powder, 6-9% fly ash, 8-9% kaolin, 4.5-5.5% PP particles with a particle size of 1-5 mm, 0.8-1.1% foaming agent, and 0.1% 6 mm organic fiber; (2) Add water to the raw materials in step (1), stir evenly and press into blocks, the amount of water added is 4% of the raw material mass; (3) Sintered into blocks at 1250℃; After cooling, the particles are crushed according to the required specifications to obtain porous light mullite particles with a particle size of >5mm and <8mm, porous light mullite particles with a particle size of >3mm and <5mm, and porous light mullite particles with a particle size of >1mm and <3mm.

8. The fully cast composite coke oven roof structure according to claim 7, characterized in that: The raw material components and mass percentages of the porous lightweight mullite particles are: 40% mullite fine powder, 16% silicon powder, 20% alumina fine powder, 8% fly ash, 9.9% kaolin, 5% PP particles with a particle size of 1-5 mm, 1% foaming agent, and 0.1% 6 mm organic fiber.

9. The fully cast composite coke oven roof structure according to any one of claims 1 to 5, characterized in that: After the upper high-strength structure is poured, the height difference between the center of the furnace top and the edge of the slope is 75 mm.

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