Method for maintaining the erosion line of the main trough of a blast furnace
Patent Information
- Application Number
- CN202611006586.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-07
- Publication Date
- 2026-09-18
AI Technical Summary
修补一次主沟，一般至少需要3-5天，该铁口不能参与排放渣铁，必然导致该区域炉缸活跃性变差，影响高炉炉况顺行
本发明采用氮化硼粉末添加常规浇注料修补主沟渣线侵蚀区域，可以增强渣铁流动区域润湿效果，缓解侵蚀速度，提高主沟使用安全性能级寿命。
Smart Images
Figure CN122773046A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of blast furnace technology, and more specifically, to a method for maintaining the erosion line of the main trench in a blast furnace. Background Technology
[0002] The blast furnace main trough is the equipment used to discharge high-temperature slag and iron during blast furnace production. Since the blast furnace operates continuously, the main trough stores high-temperature slag and iron for extended periods. Large blast furnaces typically have 3-4 tapholes, while small blast furnaces usually have 1-2, with each taphole corresponding to a main trough. Slag and iron are discharged from the tapholes in rotation. As the slag and iron flow from the tapholes into the main trough, their densities differ, resulting in slag at the top and molten iron at the bottom, achieving slag-iron separation. The slag, at the top, enters the slag trough through the slag discharge port, while the molten iron, at the bottom, enters the slag trough through the skimmer channel and flows into the ladle.
[0003] During the flow of high-temperature slag and iron in the main trough, the slag-iron interface and the flow line on the slag surface are the areas most severely eroded by the refractory material of the main trough shell (the slag contains a large amount of alkali metals and lead-zinc, etc.). Slag-iron erosion burn-through accidents in the main trough usually begin from the erosion line. During the discharge of slag and iron from the blast furnace, the slag and iron in the erosion line area are in a flowing state, constantly scouring the refractory layer on both sides of the main trough. When no slag or iron is being discharged from the taphole corresponding to the main trough, the slag-iron liquid level inside the main trough is lower than when slag and iron are being discharged. At this time, the slag-iron liquid level is in a static state, and the erosion of the refractory material by the slag and iron inside the main trough is relatively slow.
[0004] During the blast furnace slag and iron discharge process, the flow rate of slag and iron discharged from the taphole varies, causing the refractory erosion lines on both sides of the main trough to fluctuate, ultimately resulting in an irregular arc shape. This irregular arc-shaped erosion area leads to uneven thermal stress and slag-iron extrusion pressure exerted on the eroded area by the high-temperature slag and iron inside the main trough, making daily maintenance of the eroded area of the main trough extremely difficult.
[0005] The refractory lining layer on both sides of the blast furnace main trough is approximately 500mm thick. The inner side of the main trough is integrally cast, with a layer of refractory bricks laid outside the cast lining layer, and a steel shell layer added to the outside of the refractory bricks. The high-temperature slag and iron inside the blast furnace main trough experiences large temperature fluctuations. At high temperatures, the molten iron temperature reaches as high as 1550℃, while at low temperatures it is only around 1450℃ or even lower. The large changes in thermal stress along the slag-iron surface line within the main trough further exacerbate the erosion of the refractory lining. As the refractory layer erodes, cracks and fissures appear in the eroded areas. Generally, half of the cast lining layer on both sides of the main trough is eroded, requiring recasting and repair.
[0006] In existing technologies, main channel erosion cannot be repaired online during daily production because the main channel stores a large amount of high-temperature slag and iron. As erosion intensifies, it easily leads to analytical cracks in the refractory material of the main channel, potentially causing a burn-through safety accident. Typically, when the main channel's slag throughput reaches approximately 100,000 tons, operation of the main channel is stopped (corresponding to the shut-down of the taphole), the stored high-temperature slag and iron are drained, and the main channel is taken offline for repair. The repair method first involves using a blasting machine or other machinery to remove the eroded refractory layer from the eroded area of the main channel, and then recasting a new layer of refractory material. Repairing a main channel generally takes at least 3-5 days. The taphole cannot participate in slag and iron discharge, inevitably leading to decreased hearth activity in that area and affecting the smooth operation of the blast furnace. Therefore, it is necessary to propose a maintenance method for the erosion line of the blast furnace main channel. Summary of the Invention
[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for maintaining the erosion line of the blast furnace main trough. By using boron nitride powder mixed with conventional castable to repair the eroded area of the slag line in the main trough, the wetting effect of the slag-iron flow area can be enhanced, the erosion rate can be slowed down, and the service safety and lifespan of the main trough can be improved. This method enables online maintenance of the main trough, is convenient and simple to operate, and can extend the time between major overhauls of the main trough.
[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A method for maintaining the erosion line of the main blast furnace trench includes the following steps: S1. Measure the erosion thickness of the main ditch. When the erosion thickness of the main ditch reaches 50-60 mm, carry out online repair. The total volume of the eroded area is calculated based on the length of the main gully, the thickness of the erosion in the main gully, and the height of the eroded area in the main gully. S2. Mix the nano-sized boron nitride powder, high-temperature binder, and casting refractory material together, add water, and stir until homogeneous. The mixture should be homogeneous but not free-flowing. Based on the total volume of the eroded area, the volume of boron nitride powder should be 30-40% of the total volume of the eroded area, the volume of casting refractory material should be 40-50% of the total volume of the eroded area, and the volume of high-temperature binder should be 10-20% of the total volume of the eroded area. The mixture is placed in a grouting tank, where high-pressure compressed air is passed through to extrude and transport the mixture to the erosion area. It is then compacted and leveled with round wooden sticks. The mixture is then naturally baked for 1-2 hours under the high-temperature heat emitted by the slag and iron stored in the main trench before it can be used.
[0009] In one embodiment, the thickness of the main gully erosion is measured as follows: During the use of the blast furnace main ditch and when the slag and iron inside the main ditch are in a static state, the elevation of the molten iron surface in the static state of the main ditch is measured. The horizontal plane of the upper surface of the main ditch is used as a reference to obtain the elevation of the molten iron surface h1 in the static state of the main ditch. When measuring the elevation of the molten iron surface, the molten iron surface is measured through the pure molten iron area after the skimmer. The elevation of the upper slag surface h2 inside the main ditch is obtained. The thickness of the slag layer in the static state of the slag and iron inside the main ditch is obtained as ɑ1=h1-h2, which represents the erosion height of the slag layer on the refractory materials on both sides of the main ditch during the process when the slag and iron are not discharged from the main ditch. During the discharge of slag and iron in the main blast furnace ditch, the flow rate of molten iron and the flow rate of slag are recorded. The elevation h3 of the highest surface slag layer inside the main ditch is detected. ɑ2=h3-h1 represents the height of the flow line region of slag and iron inside the main ditch in the static state and the flowing state of discharged slag and iron. Select a furnace interval period during which no slag or iron is discharged from the main ditch. When the slag and iron molten surface in the main ditch is in a static state, raise the height of the slag skimmer in the main ditch using refractory material. The height of the raised material should be consistent with the height of the slag opening in the main ditch. Based on the dimensions of the main channel, the volume V1 of the upper slag layer in the main channel under static conditions is calculated. V1 = main channel liquid surface length * main channel width * α1, where V1 represents the volume of the upper slag layer in the main channel under static conditions. A volume of scrap steel V1 is placed into the main trench. The scrap steel enters the main trench and melts into molten iron in the high-temperature iron environment. After all the scrap steel has been added, there is no obvious churning of the slag and iron surface in the main trench. All the refractory material raised by the skimmer is removed. Then, the molten iron raised by the addition of scrap steel flows out with the skimmer. After the slag and iron in the main trench settles, the main trench is mainly filled with molten iron. A layer of coke powder is spread on the surface of the molten iron for heat preservation. At this time, the highest liquid level in the main trench is lower than the liquid level in the main trench under normal static state. The height of the drop is recorded as h4. ɑ3 = h3 - h4, which is the erosion thickness of the main trench that needs to be repaired.
[0010] In one embodiment, the scrap steel needs to be baked before being placed into the main trench, with the baking temperature being greater than 500°C.
[0011] In one embodiment, the scrap steel is added in three stages, with each stage adding one-third of the scrap steel by volume. Once the reaction on the slag and iron molten surface inside the main trench stops and there is no obvious churning, more scrap steel is added until all the scrap steel has been added.
[0012] In one embodiment, the coke powder thickness is 10 mm.
[0013] In one embodiment, the grouting tank includes a sealed tank body, a hopper with a discharge valve at the top of the sealed tank body for easy feeding, an air supply pipe and a pressure relief valve at the top of the sealed tank body, a triangular support at the bottom of the sealed tank body, and a grouting pipe with a grouting valve at the bottom of the sealed tank body between the triangular support brackets.
[0014] In summary, the present invention has the following beneficial effects: This invention uses boron nitride powder added to conventional castables to repair the erosion area of the slag line in the main channel. This can enhance the wetting effect in the slag and iron flow area, slow down the erosion rate, and improve the safety performance and service life of the main channel.
[0015] This invention enables online maintenance of the main channel, which is convenient and simple to operate. It can extend the time for major overhauls of the main channel and increase the iron capacity of the main channel from about 100,000 tons to about 150,000 tons, increasing the iron capacity of the main channel by 30,000 to 50,000 tons.
[0016] This invention provides an online repair method for eroded areas of the main ditch, which can reduce the amount of refractory material used for repairing the main ditch under the original technical conditions, thus saving refractory material costs. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the grouting tank of the present invention.
[0018] In the diagram: 2. Feed valve, 3. Hopper, 4. Air supply pipe and pressure relief valve, 5. Grouting pipe, 6. Sealed tank, 7. Triangular support, 8. Grouting valve. Detailed Implementation
[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0020] This invention proposes a method for maintaining the erosion line of the main blast furnace trench, as detailed below: S1. Measure the erosion thickness of the main ditch. When the erosion thickness of the main ditch reaches 50-60 mm, carry out online repair. The total volume of the eroded area is calculated based on the length of the main gully, the thickness of the erosion in the main gully, and the height of the eroded area in the main gully. S2. Mix the nano-sized boron nitride powder, high-temperature binder, and casting refractory material together, add water, and stir until homogeneous. The mixture should be homogeneous but not free-flowing. Based on the total volume of the eroded area, the volume of boron nitride powder should be 30-40% of the total volume of the eroded area, the volume of casting refractory material should be 40-50% of the total volume of the eroded area, and the volume of high-temperature binder should be 10-20% of the total volume of the eroded area. The mixture is placed in a grouting tank, where high-pressure compressed air is passed through to extrude and transport the mixture to the erosion area. It is then compacted and leveled with round wooden sticks. The mixture is then naturally baked for 1-2 hours under the high-temperature heat emitted by the slag and iron stored in the main trench before it can be used.
[0021] Preferably, the method for measuring the erosion thickness of the main gully is: During the use of the blast furnace main ditch and when the slag and iron inside the main ditch are in a static state, the elevation of the molten iron surface in the static state of the main ditch is measured. The horizontal plane of the upper surface of the main ditch is used as a reference to obtain the elevation of the molten iron surface h1 in the static state of the main ditch. When measuring the elevation of the molten iron surface, the molten iron surface is measured through the pure molten iron area after the skimmer. The elevation of the upper slag surface h2 inside the main ditch is obtained. The thickness of the slag layer in the static state of the slag and iron inside the main ditch is obtained as ɑ1=h1-h2, which represents the erosion height of the slag layer on the refractory materials on both sides of the main ditch during the process when the slag and iron are not discharged from the main ditch. During the discharge of slag and iron in the main blast furnace ditch, the flow rate of molten iron and the flow rate of slag are recorded. The elevation h3 of the highest surface slag layer inside the main ditch is detected. ɑ2=h3-h1 represents the height of the flow line region of slag and iron inside the main ditch in the static state and the flowing state of discharged slag and iron. Select a furnace interval period during which no slag or iron is discharged from the main ditch. When the slag and iron molten surface in the main ditch is in a static state, raise the height of the slag skimmer in the main ditch using refractory material. The height of the raised material should be consistent with the height of the slag opening in the main ditch. Based on the dimensions of the main channel, the volume V1 of the upper slag layer in the main channel under static conditions is calculated. V1 = main channel liquid surface length * main channel width * α1, where V1 represents the volume of the upper slag layer in the main channel under static conditions. A volume of scrap steel V1 is placed into the main trench. The scrap steel enters the main trench and melts into molten iron in the high-temperature iron environment. After all the scrap steel has been added, there is no obvious churning of the slag and iron surface in the main trench. All the refractory material raised by the skimmer is removed. Then, the molten iron raised by the addition of scrap steel flows out with the skimmer. After the slag and iron in the main trench settles, the main trench is mainly filled with molten iron. A layer of coke powder is spread on the surface of the molten iron for heat preservation. At this time, the highest liquid level in the main trench is lower than the liquid level in the main trench under normal static state. The height of the drop is recorded as h4. ɑ3 = h3 - h4, which is the erosion thickness of the main trench that needs to be repaired.
[0022] Preferably, the scrap steel needs to be baked before being put into the main trench, and the baking temperature is greater than 500℃.
[0023] Preferably, the scrap steel is added in three stages, with each stage adding one-third of the scrap steel by volume. Once the reaction on the slag and iron molten surface inside the main ditch stops and there is no obvious churning, more scrap steel is added, until all the scrap steel has been added.
[0024] Preferably, the thickness of the coke powder is 10 mm.
[0025] The technical solution of the present invention will be described below through specific embodiments.
[0026] During the operation of the blast furnace main trough (when high-temperature liquid slag and iron are stored inside the main trough) and when the slag and iron inside the main trough are in a static state (that is, when the slag and iron are not discharged from the taphole; generally, during blast furnace production, 2-3 tapholes take turns tapping iron, and each tapping time is about 120 minutes), the elevation of the molten iron level in the static state of the main trough is measured using a radar positioner. The elevation h1 of the molten iron level in the static state of the main trough is obtained with the upper surface of the main trough (that is, the horizontal plane of the furnace platform) as a reference. It is generally 300-400mm below the ground plane of the furnace platform. When measuring the elevation of the molten iron level, the molten iron level is measured in the pure molten iron area behind the skimmer (the skimmer behind the skimmer is the area before and after the skimmer; the area before the skimmer is the molten iron channel located below the skimmer, the area near the main trough is called the skimmer front eye, and the area after the molten iron outflow channel near the ladle is called the skimmer back eye; simply put, it is the area before and after the molten iron channel below the skimmer). Similarly, the elevation h2 of the upper slag liquid level inside the main channel is measured, which is generally 200-300 mm below the horizontal plane. The thickness of the slag layer in the main channel under static slag and iron conditions is then calculated as ɑ1 = h1 - h2. This slag layer represents the erosion height of the slag layer on the refractory materials on both sides of the main channel during the process before slag and iron are discharged.
[0027] During the slag and iron discharge process in the blast furnace main trough, record data for at least 30 heats over 3 consecutive days. Record the molten iron flow rate for each heat, denoted as m1, m2, m3…mn; simultaneously record the slag flow rate for each heat, denoted as k1, k2, k3…kn. Detect the liquid level h3 of the highest surface slag layer inside the main trough, typically 100-150mm below the horizontal plane. α2 = h3 - h1 represents the height of the flow line region of slag and iron in the main trough under static and flowing conditions.
[0028] The taphole channel is usually a fixed size, with a diameter of 45-60mm when the taphole is opened. Due to the pressure inside the hearth, the flow rates of molten iron and slag fluctuate. After continuous measurement for several days, the liquid level height at the daily maximum flow rate is recorded to obtain the liquid level position corresponding to a relatively large flow rate. This liquid level position represents the possible contact line between the molten iron and slag surfaces during the daily operation of the main channel.
[0029] As the number of slag and iron furnace discharges from the main trough increases, the erosion of refractory materials on both sides of the main trough intensifies, necessitating maintenance of the eroded layer in the main trough. The operation method is as follows: Select the interval period during which no slag or iron is discharged from the main trough (assuming there are two main troughs discharging slag and iron, one discharging slag and iron for approximately 120 minutes, and the other not discharging slag and iron, with the slag and iron remaining stationary in the main trough for approximately 120 minutes). Once the slag and iron surface in the main trough is stationary, raise the height of the slag skimmer's outlet using refractory material, ensuring the height matches the slag outlet height (i.e., if the slag outlet in the main trough is -100mm above the ground, the height difference between the skimmer's outlet and the ground is also -100mm). Based on the main trough dimensions and α2, calculate the volume V1 of the upper slag layer in the stationary state. V1 = main trough liquid surface length * main trough width * α2. V represents the volume of the upper slag layer in the stationary state of the main trough.
[0030] Using the extrusion principle, scrap steel with a volume of V1 is placed into the main trough. The scrap steel needs to be baked before being placed into the trough, with a baking temperature exceeding 500℃. Upon entering the main trough, the scrap steel melts in the high-temperature molten iron environment, generating molten iron and a small amount of slag. During the addition of scrap steel, it is added in stages: first, one-third of the scrap steel with a volume of V1 is added. Once the reaction between the slag and iron in the main trough stops and there is no obvious churning, the second third is added, and so on, until all the scrap steel is added in three stages. During the addition of scrap steel, the upper layer of molten slag gradually rises and is then discharged through the slag outlet. After all the scrap steel has been added, and there is no obvious churning on the slag and iron surface in the main trough, the refractory material raised behind the skimmer is removed using tools. The molten iron that rose due to the addition of scrap steel then flows out through the skimmer. Once the slag and iron in the main trough have settled, the trough mainly contains molten iron. A 10mm thick layer of coke powder is laid on the surface of the molten iron for insulation. At this point, the highest liquid level in the main channel has decreased compared to the liquid level in the main channel under normal static conditions. This decrease can be measured and recorded as h4. ɑ3 = h3 - h4, which is the height of the eroded area in the main channel that needs repair.
[0031] The erosion zone height α3 obtained from the above measurements during the slag and iron flow process in the main ditch is used as the maintenance height for the erosion line of the main ditch. The erosion thickness of the main ditch (that is, the transverse erosion depth of the refractory material cast in the main ditch, calculated from the inner side of the new main ditch casting layer) is measured using tools. When the erosion thickness reaches 50-60mm, online repair and maintenance operations are carried out on the erosion line.
[0032] Maintenance operation steps: First, the total volume V2 of the eroded area is calculated based on the erosion thickness of the main trench and the maintenance height of the erosion line. (The length of the main trench is fixed; the volume can be calculated based on the erosion thickness and the maintenance height of the erosion line.) Nano-sized boron nitride powder is mixed with conventional castable refractory material and water is added for thorough mixing. Using the total volume of the eroded area as a baseline, 30-40% of the boron nitride powder is used in V2, 40-50% of the conventional castable refractory material is used in V2, and 10-20% of the PA-80 high-temperature binder is used in V2. The three powders are mixed with a small amount of water until thoroughly stirred, ideally until the mixture is no longer free-flowing.
[0033] The mixture is placed in a grouting tank, where high-pressure compressed air is used to press and transport it to the eroded area. It is then compacted using round wooden sticks. The mixture should be pressed into the eroded area and level with the outside of the eroded area. The mixture is then allowed to bake naturally for 1-2 hours under the high-temperature heat emitted by the slag and iron stored in the main trench before use.
[0034] As the service life of the main channel is extended, continuous cyclical repair and maintenance of the eroded area will be carried out. When the molten iron storage area below the eroded area of the main channel is gradually eroded and the thickness gradually decreases, when the thickness of the molten iron storage area on both sides of the main channel (i.e. the remaining thickness of the original molten iron storage area) is half the thickness of the new main channel molten iron storage area (i.e. the thickness formed by the repaired mixture), the main channel will stop operating and be taken offline for major repairs.
[0035] Figure 1 This is a schematic diagram of the grouting tank used in this invention. The grouting tank includes a sealed tank body. A hopper with a discharge valve is installed at the top of the sealed tank body for easy material feeding. An air supply pipe and a pressure relief valve are also installed at the top of the sealed tank body. Triangular supports are installed at the bottom of the sealed tank body, and a grouting pipe with a grouting valve is installed between the triangular supports at the bottom of the sealed tank body. This grouting tank facilitates on-site construction.
[0036] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.
Claims
1. A method for maintaining the erosion line of the main blast furnace trench, characterized in that, Includes the following steps: S1. Measure the erosion thickness of the main ditch. When the erosion thickness of the main ditch reaches 50-60 mm, carry out online repair. The total volume of the eroded area is calculated based on the length of the main gully, the thickness of the erosion in the main gully, and the height of the eroded area in the main gully. S2. Mix the nano-sized boron nitride powder, high-temperature binder, and casting refractory material together, add water, and stir until homogeneous. The mixture should be homogeneous but not free-flowing. Based on the total volume of the eroded area, the volume of boron nitride powder should be 30-40% of the total volume of the eroded area, the volume of casting refractory material should be 40-50% of the total volume of the eroded area, and the volume of high-temperature binder should be 10-20% of the total volume of the eroded area. The mixture is placed in a grouting tank, where high-pressure compressed air is passed through to extrude and transport the mixture to the erosion area. It is then compacted and leveled with round wooden sticks. The mixture is then naturally baked for 1-2 hours under the high-temperature heat emitted by the slag and iron stored in the main trench before it can be used.
2. The method for maintaining the erosion line of the blast furnace main trench as described in claim 1, characterized in that, The method for measuring the erosion thickness of the main gully is as follows: During the use of the blast furnace main ditch and when the slag and iron inside the main ditch are in a static state, the elevation of the molten iron surface in the static state of the main ditch is measured. The horizontal plane of the upper surface of the main ditch is used as a reference to obtain the elevation of the molten iron surface h1 in the static state of the main ditch. When measuring the elevation of the molten iron surface, the molten iron surface is measured through the pure molten iron area after the skimmer. The elevation of the upper slag surface h2 inside the main ditch is obtained. The thickness of the slag layer in the static state of the slag and iron inside the main ditch is obtained as ɑ1=h1-h2, which represents the erosion height of the slag layer on the refractory materials on both sides of the main ditch during the process when the slag and iron are not discharged from the main ditch. During the discharge of slag and iron in the main blast furnace ditch, the flow rate of molten iron and the flow rate of slag are recorded. The elevation h3 of the highest surface slag layer inside the main ditch is detected. ɑ2=h3-h1 represents the height of the flow line region of slag and iron inside the main ditch in the static state and the flowing state of discharged slag and iron. Select a furnace interval period during which no slag or iron is discharged from the main ditch. When the slag and iron molten surface in the main ditch is in a static state, raise the height of the slag skimmer in the main ditch using refractory material. The height of the raised material should be consistent with the height of the slag opening in the main ditch. Based on the dimensions of the main channel, the volume V1 of the upper slag layer in the main channel under static conditions is calculated. V1 = main channel liquid surface length * main channel width * α1, where V1 represents the volume of the upper slag layer in the main channel under static conditions. A volume of scrap steel V1 is placed into the main trench. The scrap steel enters the main trench and melts into molten iron in the high-temperature iron environment. After all the scrap steel has been added, there is no obvious churning of the slag and iron surface in the main trench. All the refractory material raised by the skimmer is removed. Then, the molten iron raised by the addition of scrap steel flows out with the skimmer. After the slag and iron in the main trench settles, the main trench is mainly filled with molten iron. A layer of coke powder is spread on the surface of the molten iron for heat preservation. At this time, the highest liquid level in the main trench is lower than the liquid level in the main trench under normal static state. The height of the drop is recorded as h4. ɑ3 = h3 - h4, which is the erosion thickness of the main trench that needs to be repaired.
3. The method for maintaining the erosion line of the blast furnace main trench as described in claim 2, characterized in that, The scrap steel needs to be baked before being put into the main trench, and the baking temperature is greater than 500℃.
4. The method for maintaining the erosion line of the blast furnace main trench as described in claim 2, characterized in that, During the addition of scrap steel, it is added in three stages, each time one-third of the volume of scrap steel is added. Once the reaction on the surface of the slag and iron in the main ditch stops and there is no obvious rolling phenomenon on the surface of the slag and iron, the scrap steel is added again until all the scrap steel has been added.
5. The method for maintaining the erosion line of the blast furnace main trench as described in claim 2, characterized in that, The thickness of the coke powder is 10 mm.
6. The method for maintaining the erosion line of the blast furnace main trench as described in claim 1, characterized in that, The grouting tank includes a sealed tank body. The top of the sealed tank body is equipped with a hopper with a discharge valve for easy feeding. The top of the sealed tank body is also equipped with an air supply pipe and a pressure relief valve. The bottom of the sealed tank body is equipped with a triangular support. Between the triangular support, the bottom of the sealed tank body is equipped with a grouting pipe with a grouting valve.