A method for integrally casting the iron mouth of a newly built or overhauled blast furnace

Abstract

A method for integral casting of a newly built or overhauled blast furnace iron mouth belongs to the technical field of blast furnace ironmaking. The following steps are adopted: S1. Fix the embedded pipe on the center line of the iron mouth channel; S2. Pour the castable into the iron mouth frame; S3. Insert the vibrating rod into the castable in the iron mouth frame for vibration to increase the density of the castable, repeat the pouring of the castable and the vibration operation of the vibrating rod until the dense castable fills the entire space in the iron mouth frame; S4. Maintain the castable: the curing time is 4-72 hours, and the embedded pipe is rotated every 2-12 hours; S5. Pull out the embedded pipe to complete the casting process. The iron mouth castable is dense, which prevents gas leakage from the iron mouth of the blast furnace, and at the same time reduces the gas splashing when the blast furnace is tapping iron, avoids the occurrence of blast furnace gas poisoning and molten iron scalding accidents caused by excessive CO concentration and molten iron splashing in the iron mouth area, and improves the working environment of the workers in front of the furnace.

Description

Technical Field

[0001] The invention relates to a method for integrally casting an iron mouth of a newly built or overhauled blast furnace, belonging to the technical field of blast furnace ironmaking. Background Art

[0002] When a new blast furnace is built or overhauled, the quality of the masonry of the hearth and the iron mouth directly affects the life of the blast furnace during the entire masonry process. In order to ensure the masonry quality of the hearth and the iron mouth of the blast furnace, the traditional masonry method is to order special bricks for the hearth and the iron mouth from the refractory manufacturer, and pre-build them in the refractory supplier to ensure that the brick structure and brick joint size meet the standards after masonry. This method can provide material guarantee for improving the masonry quality of the iron mouth, but the construction cost is too high. With the continuous updating of refractory products, especially the development of castable products, some manufacturers have also updated the construction method for the iron mouth when building a new blast furnace or overhauling a blast furnace. That is, after the masonry of the carbon bricks in the hearth is completed, the castable is injected into the iron mouth frame and the iron mouth channel of the carbon bricks on the outside of the iron mouth for overall casting. The following problems exist when this method is used for pouring the iron mouth of a blast furnace: first, the construction time is long, which is time-consuming and laborious; second, the construction visibility is poor and the construction quality cannot be guaranteed, especially when the castable is injected into the iron mouth frame from the outside of the iron mouth, it is impossible to observe whether the castable in the iron mouth frame is full. If the castable is not fully filled inside the iron mouth frame, when the blast furnace is started after the pouring is completed, the castable will expand or contract at high temperature, causing cracks in the castable in the iron mouth area, etc. The gas in the blast furnace hearth will escape from the furnace through the internal gap of the iron mouth frame, causing the CO content in the working area around the iron mouth to increase, directly threatening the life safety of the workers in front of the blast furnace. At the same time, the hearth gas will rush out along the iron mouth when the blast furnace is tapping iron, causing the iron mouth to splash, which directly affects the normal production organization of the blast furnace and needs to be improved urgently. Summary of the invention

[0003] The purpose of the present invention is to provide a method for integrally casting the iron mouth of a newly built or overhauled blast furnace, so as to solve the problems existing in the above-mentioned prior art.

[0004] The technical solution to solve the above technical problems is:

[0005] A method for integrally casting the iron mouth of a newly built or overhauled blast furnace, which is carried out by the following steps:

[0006] S1. Fix the embedded pipe on the center line of the iron mouth channel;

[0007] S2. Pour the castable into the iron mouth frame;

[0008] S3. Insert the vibrating rod into the castable in the iron mouth frame to vibrate, increase the density of the castable, repeat the pouring of the castable and the vibration rod vibration operation until the dense castable fills the entire iron mouth frame space;

[0009] S4. Curing castable: curing time 4-72 hours, rotating the embedded pipe every 2-12 hours;

[0010] S5. Pull out the embedded pipes and complete the pouring process.

[0011] In the above-mentioned method for integral casting of the iron mouth of a newly built or overhauled blast furnace, the embedded pipe in step S1 is a steel pipe with an outer diameter of 60-100 mm, and the length extends out of the iron mouth frame and the ceramic cup wall in the furnace by 200-250 mm respectively;

[0012] In the above-mentioned method for integral casting of the iron mouth of a newly built or overhauled blast furnace, a handle is provided at the end of the embedded pipe in step S1, and the handle can be directly welded to the end of the embedded pipe or a steel pipe can be inserted in the space 50 mm away from the end.

[0013] In the above-mentioned method for integral casting of the iron mouth of a newly built or overhauled blast furnace, the outer layer of the embedded pipe in step S1 is wrapped with a flexible isolation layer, the isolation layer can be made of oil paper, and then transparent tape is used to wrap the oil paper, and the length of the wrapped oil paper and tape is the length of the iron mouth channel.

[0014] In the above-mentioned method for integral casting of the iron mouth of a newly built or overhauled blast furnace, the volume density of the castable in step S2 is ≥3.2g / m3, Al2O3: 86~90%, SiO2: 3.5~6%, Fe2O3≤0.5%, TiO2: 4~10%, the amount of water added during stirring is 4-6% of the weight of the castable, and the linear change rate after firing (1500℃×3h) is 0~+1%.

[0015] In the above-mentioned method for integral casting of the iron mouth of a newly built or overhauled blast furnace, in step S4, before the initial setting of the castable, round steel with a diameter of 4-6 mm and a length of 200-250 mm is inserted into the exhaust pipe for 2-4 times to facilitate the synchronous solidification and shrinkage of the castable in the exhaust pipe and the castable in the iron mouth frame.

[0016] The present invention performs integral casting of the iron mouth during the construction of a new or overhauled blast furnace, and assists in the vibration operation of a vibrating rod, so that the iron mouth castable is dense, and gas leakage at the iron mouth of the blast furnace is prevented. The CO concentration in the iron mouth area is reduced from 200 ppm to 22-45 ppm, and the gas splashing during iron tapping from the blast furnace can be reduced, so as to avoid blast furnace gas poisoning and molten iron scalding accidents caused by excessively high CO concentration and molten iron splashing in the iron mouth area, thereby improving the working environment of the workers in front of the furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is a schematic diagram of the iron mouth area before pouring of the present invention;

[0018] Figure 2 It is the side view of the iron mouth frame;

[0019] Figure 3 This is the process diagram when pouring 1 / 2;

[0020] Figure 4 This is the taphole diagram after pouring is completed;

[0021] Figure 5 This is the tube pulling diagram after the castable has completed solidification;

[0022] Figure 6 Diagram of pre-buried pipelines for the iron mouth channel;

[0023] Markings in the figure are: 1-cooling wall, 2-furnace shell, 3-exhaust pipe, 4-iron mouth frame, 5-iron mouth frame sealing plate entrance outside blast furnace, 6-outer iron mouth frame sealing plate, 7-iron mouth channel embedded pipe, 8-outer iron mouth casting lower sealing plate, 9-loading barrel, 10-casting material, 11-iron mouth castable material and vibrating rod entrance, 12-clay brick, 13-wooden board, 14-iron mouth carbon brick, 15-ceramic cup wall, 16-iron mouth channel furnace sealing plate, 17-air outlet platform crossbeam I-beam, 18-T-shaped support I-beam, 19-buried pipe traction ear, 20-fall chain, 21-handle. Implementation

[0024] The example is a newly built 3200m 3 The method of integral casting of blast furnace iron mouth. Due to the elimination of backward blast furnace ironmaking capacity, equipment upgrading and transformation were carried out to build a new blast furnace. 3 During the blast furnace masonry process, the iron mouth is cast as a whole. The specific steps of the casting construction are as follows:

[0025] S1. Fix the embedded pipe on the center line of the iron mouth channel

[0026] First, a seamless steel pipe with an outer diameter of φ=89mm and a wall thickness of 4mm is selected. According to the blast furnace construction drawings, the thickness of the inner wall of the ceramic cup wall from the outside of the blast furnace iron mouth frame to the blast furnace is 3000mm. A seamless steel pipe with a length of 3400mm is cut as the embedded pipe 7 for integral casting of the blast furnace iron mouth. A handle 21 is provided at the outer end of the embedded pipe 7 to facilitate the rotation of the iron mouth embedded pipe 7 after casting. The embedded pipe 7 is wrapped with a layer of oil paper, and then a transparent tape is used to wrap it on the oil paper. The length of the wrapped oil paper and tape is the length of the iron mouth channel, so that the embedded pipe 7 can be easily pulled out after casting.

[0027] Insert the embedded pipe 7 into the iron mouth channel. First, fix one end of the embedded pipe 7 on the inner side of the blast furnace. Take a steel plate with a thickness of 8mm and a side length of 400×400mm as the iron mouth channel furnace inner sealing plate 16, and draw a cross center line on the iron mouth channel furnace inner sealing plate 16 to determine the center of the iron mouth channel furnace inner sealing plate 16, and open a circular hole with a diameter of 90mm at its center position; draw a cross line on the surface of the inner brick hole of the ceramic cup wall 15 inside the blast furnace to determine the center position of the iron mouth, and overlap the cross line of the iron mouth channel furnace inner sealing plate 16 with the cross line on the surface of the ceramic cup wall 15 bricks and make the iron mouth channel furnace inner sealing plate 16 close to the surface of the ceramic cup wall 15 bricks, and then use two round steel bars with a diameter of 16mm to weld the iron mouth channel furnace inner sealing plate 16 to the furnace scaffolding, so that the iron mouth channel furnace inner sealing plate 16 is firmly fixed to the surface of the ceramic cup wall 15 bricks, and then use two round steel bars with a diameter of 16mm to weld the iron mouth channel furnace inner sealing plate 16 to the furnace scaffolding, so that the iron mouth channel furnace inner sealing plate 16 is firmly fixed to the surface of the ceramic cup wall 15 bricks.

[0028] Then fix the other end of the embedded pipe 7. Take a steel plate with a thickness of 8mm and a side length of 400×400mm, draw a cross line on the steel plate to locate the center, and open a circular hole with a diameter of 90mm in the center of the steel plate. After opening the hole, divide the steel plate into two pieces, the upper steel plate is used as the outer iron mouth frame sealing plate 6, and the lower steel plate is used as the lower sealing plate 8 for pouring the iron mouth outside the furnace. First, overlap the cross lines of the lower sealing plate 8 for pouring the iron mouth outside the furnace with the cross lines on the iron mouth frame 4 and weld them to fix. Place the embedded pipe 7 in the semicircular hole, and when the castable in the iron mouth frame 4 is poured close to the upper edge of the lower sealing plate 8 for pouring the iron mouth outside the furnace, dock and fix the outer iron mouth frame sealing plate 6 with the lower sealing plate 8 for pouring the iron mouth outside the furnace to seal the channel.

[0029] S2. Pour the castable into the iron mouth frame

[0030] A wooden board 13 with a thickness of 12 mm and a length and width of 1200×1000 mm is laid on the upper surface of the iron mouth carbon bricks 14 built at the iron mouth in the blast furnace to prevent the barrel 9 containing high-alumina castable 10 from hitting the surface of the iron mouth carbon bricks 14 and causing damage to the iron mouth carbon bricks 14, and to prevent the castable 10 from being scattered on the upper surface of the iron mouth carbon bricks 14 and contaminating the iron mouth carbon bricks 14; a layer of clay bricks 12 is laid on the wooden board 13, and the surface of the clay bricks 12 is 150 mm higher than the upper edge of the iron mouth frame 4.

[0031] After laying the clay bricks 12, the bucket 9 containing the stirred high-aluminum castable 10 is hoisted onto the wooden board 13 in the blast furnace, and the castable 10 in the bucket 9 is poured into the iron mouth frame 4 from the gap between the iron mouth carbon brick 14 and the iron mouth frame 4, i.e., the iron mouth castable and vibrating rod inlet 11. The selected high-aluminum castable 10 has a volume density of 3.24g / m 3 , Al2O3: 86.15%, SiO2: 6.0%, Fe2O3: 0.35%, TiO2: 7.5%, after firing (1500℃×3h) linear change rate: +0.3%. The amount of water added during stirring is 5.5% of the weight of the high-alumina castable.

[0032] S3. Casting process: After the castable 10 is poured into the iron mouth frame 4, a vibrating rod is placed into the iron mouth frame 4 from the entrance 5 of the iron mouth frame sealing plate outside the blast furnace, and at the same time, another vibrating rod is put into the iron mouth castable and vibrating rod entrance 11. The vibrating rod is operated to vibrate while pouring the castable 10, so that the castable 10 can quickly fill the iron mouth carbon bricks 14 and the iron mouth channels in the ceramic cup wall 15 with the castable 10 fully and evenly in the iron mouth frame 4.

[0033] When the casting surface of the castable material 10 rises to the upper edge of the lower sealing plate 8 for casting the iron mouth outside the furnace, the outer iron mouth frame sealing plate 6 is connected and fixed to the lower sealing plate 8 for casting the iron mouth outside the furnace to seal the iron mouth channel, and the casting is continued until the castable material 10 material surface rises to the exhaust pipe 3 on the iron mouth frame 4, and the castable material 10 of the exhaust pipe 3 overflows, and the casting is completed. The castable material 10 directly contacts the cold surface of the iron mouth carbon brick 14 without leaving a gap, thereby avoiding the occurrence of gas leakage and iron splashing in the iron mouth area after the blast furnace is put into production.

[0034] S4. Curing castable

[0035] Since the castable 10 is in a relatively sealed environment and the binder of the castable 10 is water, the curing time is relatively long. The castable 10 in the part in contact with the air between the iron mouth carbon brick 14 and the iron mouth frame 4 in the blast furnace reaches strength in 4-6 hours. After 5 hours and 40 minutes after pouring, the clay bricks 12 and the wooden board 13 on the upper surface of the iron mouth carbon brick 14 are removed, and the carbon bricks are continued to be laid. At 24 hours, 48 ​​hours and 60 hours after pouring, a round steel pipe with a diameter of 6mm and a length of 250mm is inserted into the exhaust pipe 3 for exhaust 3 times, so that when the castable 10 solidifies and shrinks, the castable 10 in the exhaust pipe 3 and the iron mouth frame 4 shrink synchronously, which is convenient for observing the shrinkage; 60 hours after pouring, the embedded pipe 7 is rotated to prevent the embedded pipe 7 from being unable to be pulled out. The embedded pipe 7 is rotated 3 times a day before being pulled out.

[0036] S5. Pull out the embedded pipes and complete the pouring process.

[0037] Due to the large volume of the blast furnace, the embedded pipe 7 in the iron mouth channel is long. After the casting of the curing castable 10 is completed, it is impossible to smoothly pull the embedded pipe 7 out of the iron mouth channel by manpower alone, so it is necessary to use tools to pull out the embedded pipe 7. To this end, a T-shaped support I-beam 18 is set above the main iron groove in front of the iron mouth frame 4, and a lifting lug 19 for traction of the embedded pipe is welded on the T-shaped support I-beam 18. The 3t fall chain 20 is hung on the lifting lug 19 for traction of the embedded pipe. The position of the lifting lug 19 is on the same center line as the embedded pipe 4. The fall chain 20 is connected to the embedded pipe 7 by bolts, and the fall chain 20 is pulled to pull out the embedded pipe 7.

[0038] In this embodiment, a new 3200m 3The CO concentration value and splashing situation in the iron mouth area in the first 10 days after the blast furnace is opened are shown in Table 1. However, the blast furnace with coal gas leakage at the iron mouth has serious splashing during normal iron tapping, which is difficult to control. At the same time, the CO concentration value in the iron mouth area is above 200ppm for a long time.

[0039] Table 1 Iron mouth area situation in the first 10 days after the start-up of 3200m3 blast furnace

[0040] .

Claims

1. A method for integral casting of a newly built or overhauled blast furnace iron mouth, characterized in that , which is carried out using the following steps: S1. Fix the embedded pipe (7) on the center line of the iron mouth channel, and wrap the outer layer of the embedded pipe (7) with a flexible isolation layer, the length of the isolation layer is the length of the iron mouth channel: first fix one end of the embedded pipe (7) inside the blast furnace, take a steel plate as the iron mouth channel furnace inner sealing plate (16), and draw a cross center line on the iron mouth channel furnace inner sealing plate (16) to determine the center of the iron mouth channel furnace inner sealing plate (16), and open a circular hole at its center position; draw a cross line on the surface of the brick hole inside the ceramic cup wall (15) inside the blast furnace to determine the center position of the iron mouth, make the cross line of the iron mouth channel furnace inner sealing plate (16) coincide with the cross line on the brick surface of the ceramic cup wall (15) and make the iron mouth channel furnace inner sealing plate (16) close to the brick surface of the ceramic cup wall (15), and then use two round steel bars to fix the iron mouth channel furnace The inner sealing plate (16) is welded to the scaffolding inside the furnace so that the inner sealing plate (16) of the iron mouth channel is tightly attached to the surface of the ceramic cup wall (15) brick and fixed firmly; then the other end of the embedded pipe (7) is fixed, a steel plate is taken, a cross line is drawn on the steel plate to locate the center, and a circular hole is opened in the center of the steel plate, and the steel plate is divided into two upper and lower pieces, the upper steel plate is used as the outer iron mouth frame sealing plate (6), and the lower steel plate is used as the outer iron mouth casting lower sealing plate (8), firstly, the cross line of the outer iron mouth casting lower sealing plate (8) is overlapped with the cross line on the iron mouth frame (4) and tightly attached and welded, and the embedded pipe (7) is placed in the semicircular hole, and when the castable in the iron mouth frame (4) is poured to close to the upper edge of the outer iron mouth casting lower sealing plate (8), the outer iron mouth frame sealing plate (6) is butt-jointed with the outer iron mouth casting lower sealing plate (8) to fix the sealed channel; S2. Pour the castable into the iron mouth frame (4); S3. Insert a vibrating rod into the castable in the iron mouth frame to vibrate the castable to increase the density of the castable. Repeat the pouring of castable and vibrating operation until the dense castable fills the entire space inside the iron mouth frame (4). The specific process is as follows: after the castable (10) is poured into the iron mouth frame (4), a vibrating rod is placed into the iron mouth frame (4) from the entrance (5) of the iron mouth frame sealing plate outside the blast furnace. At the same time, another vibrating rod is placed from the entrance (11) of the iron mouth castable and vibrating rod. While pouring the castable (10), the vibrating rod is operated to vibrate so that the castable (10) can make the iron mouth carbon The iron mouth passages in the bricks (14) and the ceramic cup walls (15) are quickly filled with the castable (10) in the iron mouth frame 4, which is full and uniform; when the casting surface of the castable (10) rises to the upper edge of the iron mouth casting lower sealing plate (8) outside the furnace, the outer iron mouth frame sealing plate (6) is connected and fixed to the iron mouth casting lower sealing plate outside the furnace to seal the iron mouth passages, and the casting is continued until the castable (10) material surface rises to the exhaust pipe (3) on the iron mouth frame (4), and the castable (10) of the exhaust pipe (3) overflows, and the casting is completed; the castable is directly in contact with the cold surface of the iron mouth carbon brick (14) without leaving any gaps; S4. Curing the castable for 4-72 hours and rotating the embedded pipe (7) every 2-12 hours; S5. Pull out the embedded pipe (7) and complete the pouring process, specifically: set a T-shaped support I-beam (18) above the main iron groove in front of the iron mouth frame (4), weld the embedded pipe traction lug (19) on the T-shaped support I-beam (18), hang the fall chain (20) on the embedded pipe traction lug (19), the lug (19) is located on the same center line as the embedded pipe (7), the fall chain (20) is connected to the embedded pipe (7) by bolts, and the fall chain (20) is pulled to pull out the embedded pipe (7).

2. The method for integrally casting the iron mouth of a newly built or overhauled blast furnace according to claim 1, characterized in that The embedded pipe (7) in step S1 is a steel pipe with an outer diameter of 60-100 mm, and its length extends out of the iron mouth frame (4) and the ceramic cup wall (15) in the furnace by 200-250 mm.

3. The method for integrally casting the iron mouth of a newly built or overhauled blast furnace according to claim 1, characterized in that The embedded pipe (7) in step S1 is provided with handles (21) at both ends.

4. The method for integrally casting the iron mouth of a newly built or overhauled blast furnace according to claim 1, characterized in that The bulk density of the casting material (10) in step S2 is ≥3.2 g / m 3 , Al2O3: 86~90%, SiO2: 3.5~6%, Fe2O3≤0.5%, TiO2: 4~10%, add 4-6% water during stirring, the linear change rate after sintering at 1500℃×3h is 0~+1%.

5. The method for integral casting of a newly built or overhauled blast furnace iron mouth according to claim 1, characterized in that In step S3, the castable is cured for 2-72 hours, and before initial setting, a steel pipe with a diameter of 4-6 mm and a length of 200-250 mm is inserted into the exhaust pipe (3) for exhaust 2-4 times, so that when the castable (10) solidifies and shrinks, the castable (10) in the exhaust pipe (3) and the castable (10) in the iron mouth frame (4) shrink synchronously.

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