A method for efficiently removing lining bricks of a live bottom converter

Abstract

The present invention discloses a method for efficiently removing lining bricks of a live furnace bottom converter, and belongs to the technical field of converter furnace condition maintenance technology. The method comprises the following steps: (1) measuring the residual thickness of the converter lining bricks and the height of the converter bottom; (2) preparing for furnace shutdown; (3) performing furnace washing operation; (4) cooling the furnace by soaking in water; (5) separating the furnace bottom from the furnace body; and (6) removing the lining bricks. The oxygen pressure, oxygen flow rate, oxygen blowing time, oxygen gun position, and soaking and eroding slag splashing layer time are controlled by the residual thickness of the converter lining bricks and the height of the converter bottom. The present invention improves the removal efficiency of the converter lining bricks and shortens the furnace service life while ensuring the safety of the operation.

Description

Technical Field

[0001] The invention belongs to the technical field of converter steelmaking furnace condition maintenance technology, and more specifically, relates to a method for efficiently removing lining bricks of a movable bottom converter. Background Art

[0002] The converter is a key metallurgical equipment in a steel plant. During the blowing process, the converter lining bricks are easily corroded and damaged during use due to the extremely complex and intense physical and chemical reactions and mechanical movements in the furnace, the mechanical scouring of molten iron and scrap steel, the chemical erosion of molten steel and slag on the lining, and the peeling of the lining caused by temperature gradient changes. When the working layer of the converter lining is eroded to a residual thickness of about 100mm, the lining must be replaced. Otherwise, not only will the cost of refractory materials for furnace maintenance increase, but steel leakage accidents are also very likely to occur. For a live-bottom converter, before replacing the lining, the furnace bottom and the furnace body are usually separated first, and then the damaged old lining bricks of the furnace bottom and the furnace body are removed cleanly, and finally the furnace can be built. Because the residual lining bricks of the converter are attached to the surface of the steel slag and the bricks are squeezed and bonded to form a whole, it is not easy to remove. The traditional method of removing converter lining bricks is: first use natural cooling to cool the high-temperature lining bricks after washing to 150-250℃, then use a furnace removal machine to hammer the lining bricks layer by layer from the top of the furnace mouth, using the principle that the layer of fallen lining bricks loses the mutual squeezing and fixing force between bricks, and then cooperate with the furnace shaking operation to make the other bricks of each layer fall off during the shaking process, so that the lining bricks of the entire converter can be completely removed in this cycle. It usually takes about 40 hours or even longer to remove the remaining bricks of a converter in this way.

[0003] After searching, the patent document with Chinese patent application number 202110465004.7 and application publication date August 6, 2021 disclosed a method for efficiently removing refractory bricks of a converter, comprising the following steps: the first step, after the last batch of steel smelting in the converter is completed and the steel is tapped, oxygen is blown into the converter through an oxygen lance to flush the furnace, and the slag layer of the converter lining is oxidized and flushed by high-pressure oxygen until the refractory brick body of the lining is exposed, and a higher gun position is used to accelerate the flushing and loosening of the refractory bricks at the furnace mouth, preparing for the next step of removing the refractory bricks at the furnace mouth and furnace cap; the second step, the furnace mouth, steel tapping port, manhole and bottom blowing air bricks of the converter are hammered by a furnace dismantling machine to penetrate the refractory materials at the above-mentioned locations; the third step, the furnace dismantling machine is used to hammer the refractory bricks from the top layer to the bottom. When part of the top refractory bricks falls off, the furnace is shaken, and then the newly produced top refractory bricks are hammered again. By repeating this cycle, all the refractory bricks of the entire converter can be removed. This method has played a positive role in the removal of converter lining bricks, but the method does not provide detailed instructions on how to cool the high-temperature lining bricks after furnace washing to a temperature suitable for furnace dismantling operations. If the lining bricks are directly removed, not only will the working environment be poor, but the safety risk of furnace dismantling operations will also be increased. In addition, this method adopts a top-down layer-by-layer removal method, which requires frequent furnace shaking and coordination. The operation process is redundant and complicated, the labor intensity is high, and the operation efficiency is low.

[0004] Chinese patent application No. 202011501157.4, with an application publication date of April 30, 2021, discloses a method for efficiently removing the slag splash layer at the joint between the bottom and the body of a live bottom converter, the efficient removal method comprising preparatory work before shutdown, shutdown operation, oxygen blowing operation in the furnace, soaking and eroding the slag splash layer at the joint between the bottom and the body, and inspecting and confirming the slag splash layer at the joint between the bottom and the body. The efficient removal method of the present invention can effectively remove the slag splash layer, and according to the actual measured thickness of the working layer of the furnace lining and the actual value of the furnace bottom height before shutdown, the oxygen gun position, oxygen supply intensity and soaking and erosion time are reasonably controlled, so that the slag splash layer of the bottom and the body can be cleaned while avoiding steel leakage accidents. It also has the characteristics of short time, stable operation and high safety factor. The furnace washing operation time can be controlled within 30 minutes, and the work efficiency is high. However, this method is mainly aimed at removing the slag splash layer at the joint between the bottom and the furnace body of the active furnace bottom converter, and the steps for removing the slag splash layer attached to the furnace lining bricks above the joint between the bottom and the furnace body are not elaborated in detail. In addition, this method also does not fully consider the residual thickness of the furnace lining bricks, especially the weakest part of the furnace lining bricks, the control requirements of oxygen pressure, oxygen flow, oxygen gun position, oxygen blowing time and immersion erosion time of the slag splash layer during the furnace cleaning operation.

[0005] In order to improve the efficiency of converter lining brick removal and converter operation rate and shorten the service life, it is urgent to find a method for efficient converter lining brick removal that is safe, reliable, time-saving and labor-saving. Summary of the invention

[0006] 1. Problems to be solved

[0007] In view of the technical problem in the prior art that it takes a long time to remove the converter lining bricks, which leads to a long converter service cycle and thus seriously affects the improvement of the converter production efficiency, under the premise of ensuring operation safety, in order to improve the removal efficiency of the converter lining bricks and shorten the service cycle, the present invention provides a method for efficiently removing the converter lining bricks.

[0008] 2. Technical solution

[0009] To solve the above problems, the present invention adopts the following technical solutions.

[0010] A method for efficiently removing lining bricks of a live bottom converter comprises the following steps: 24 hours before the planned shutdown of the converter, no furnace repair is arranged. One furnace before the planned shutdown, after steel tapping is completed, the slag in the furnace is completely turned over.

[0011] (1) Measuring the residual thickness of converter lining bricks and the height of converter bottom to provide reference for the oxygen pressure, oxygen flow, oxygen blowing time, oxygen lance position and immersion erosion time control of slag splashing layer when removing the slag splashing layer attached to the joint between furnace body and furnace bottom and the surface of converter lining bricks. The purpose is to: 1) reasonably limit the oxygen lance pressure, flow, lance position and oxygen blowing time according to the residual thickness of the thinnest part of the furnace lining bricks and the erosion rate of the slag splashing layer of the furnace lining bricks to avoid steel leakage during the furnace cleaning process; 2) reasonably limit the immersion erosion time according to the measurement data of the converter bottom height to achieve the purpose of rapid and uniform removal of the slag splashing layer at the joint between furnace bottom and furnace body;

[0012] (2) Preparation for shutdown;

[0013] (3) Furnace washing operation: The method of blowing oxygen to wash the furnace is adopted. A supersonic oxygen jet is blown into the furnace through an oxygen gun. The oxygen reacts with the iron element in the slag reserved in the furnace. The reaction thermodynamic equation is as follows:

[0014]

[0015] Under the conditions of converter steelmaking temperature, the above reaction formula has △GΘ<0, the reaction proceeds in the positive direction, and the reaction is an exothermic reaction. After the reaction, high temperature and high (FeO) content slag are generated, which meets the thermodynamic conditions of high temperature and high (FeO) content slag required for eroding the splashing slag layer attached to the surface of the converter lining bricks. At the same time, by rationally controlling the oxygen lance position, oxygen flow, oxygen blowing time and immersion erosion time in stages, the oxygen jet is used to flush and stir the splashing slag layer attached to the surface of the lining bricks in various parts of the converter, which plays a role in quickly and evenly eroding the splashing slag layer attached to the surface of the lining bricks and preventing steel leakage accidents during the furnace washing process.

[0016] in:

[0017] The corresponding relationship between the residual thickness of the furnace lining bricks and the oxygen pressure, flow rate and oxygen blowing time is:

[0018]

[0019] The corresponding relationship between the converter bottom height and the immersion erosion slag splashing layer time is:

[0020]

[0021] (4) Cool the furnace with water;

[0022] (5) The furnace bottom and the furnace body are separated;

[0023] (6) Removal of furnace lining bricks.

[0024] Furthermore, in step (1), a Lacam M3 laser thickness gauge is used to measure the residual thickness of the converter lining bricks and the height of the converter bottom.

[0025] Furthermore, in step (2), the furnace is shut down for a period of time, and when the molten steel in the furnace is smelted normally and all the molten steel is discharged, the converter is tilted toward the slag discharge side to pour out part of the slag in the furnace, and the amount of remaining slag is controlled to be 20-30 kg / t steel.

[0026] Furthermore, in step (2), the reference angle for slag pouring in the converter is 100 to 105°.

[0027] Furthermore, in step (3), the specific steps of the furnace washing operation are:

[0028] 1) The converter is shaken to the zero position (the converter is in a vertical state), and oxygen is blown from the lower lance, with the oxygen lance position at 900-1000mm;

[0029] 2) When the oxygen blowing time reaches 5 minutes, raise the oxygen lance position to 3900-4000mm, and lower the lance position by 500-600mm at regular intervals to carry out oxygen blowing operation until the oxygen lance position is lowered to 900-1000mm;

[0030] 3) When the oxygen blowing time reaches 8.5 minutes, lift the gun to the waiting point of 6500mm and stop blowing oxygen; keep the converter at zero position, soak and erode the residual splashing slag layer attached to the surface of the furnace lining bricks for 10 minutes, then tilt the converter at an angle of 100-102°, pour out 1 / 2 of the total amount of slag in the furnace, and observe the removal of the splashing slag layer on the surface of the furnace lining bricks;

[0031] 4) If the slag splashing layer on the surface of the furnace lining brick is completely removed and the furnace lining brick body is exposed, the furnace cleaning operation is completed; if the slag splashing layer on the surface of the furnace lining brick is not completely removed and there is still some residue attached, and the furnace lining brick body is not exposed, repeat steps 1) to 3).

[0032] Taking the residual thickness of furnace lining bricks as 200-300mm and the converter bottom height as 100-200mm as an example, the specific steps of furnace washing operation are as follows:

[0033] 1) The converter is shaken to zero position, and oxygen is blown from the lower gun. The oxygen pressure is 0.5-0.6 MPa, and the oxygen flow rate is 10500-12000 Nm 3 / h, oxygen lance position 900 ~ 1000mm. Relatively large oxygen pressure and relatively low lance position are used to make oxygen fully react with residual iron in slag, so as to achieve rapid temperature rise and obtain high temperature and high (FeO) content slag. The oxygen blowing time is 5min.

[0034] 2) When the oxygen blowing time reaches 5 minutes, set the oxygen pressure to 0.3-0.4 MPa and the oxygen flow rate to 6500-8500 Nm 3 / h, raise the oxygen lance position to 3900-4000mm, then lower the oxygen lance position by 500-600mm every 0.5min to perform oxygen blowing operation until the oxygen lance position is lowered to 900-1000mm. The purpose of using a relatively small oxygen pressure and oxygen lance position from high to low oxygen blowing operation mode is, on the one hand, to avoid steel leakage accidents during furnace washing; on the other hand, to make the oxygen jet flush and stir the slag layer attached to the surface of the furnace lining bricks in various parts of the converter, which plays a role in accelerating and uniformly eroding the slag layer on the surface of the furnace lining bricks, which is conducive to the erosion and peeling of the slag layer, and continue to blow oxygen for 3.5min.

[0035] 3) When the oxygen blowing time reaches 8.5 minutes, lift the gun to the waiting point of 6500mm and stop blowing oxygen. Keep the converter at zero position, soak and erode the residual slag layer attached to the surface of the furnace lining bricks for 10 minutes, then tilt the converter at a reference angle of 100-102°, pour out 1 / 2 of the total amount of slag in the furnace, and observe the removal of the slag layer on the surface of the furnace lining bricks.

[0036] 4) If the slag layer on the surface of the furnace lining brick is completely removed and the furnace lining brick body is exposed, the furnace cleaning operation is completed; if the slag layer on the surface of the furnace lining brick is not completely removed and there is still some residue attached, and the furnace lining brick body is not exposed, repeat steps 1) to 3), where: oxygen pressure 0.5~0.6MPa, oxygen flow rate 10500~12000Nm 3 / h, oxygen lance position 900 ~ 1000mm, low lance oxygen blowing time shortened from 5min to 3min; oxygen pressure 0.3 ~ 0.4MPa, oxygen flow 6500 ~ 8500Nm 3 / h, raise the oxygen lance position to 3900-4000mm, and then, lower the lance position by 500-600mm every 0.5min to continue the oxygen blowing operation until the oxygen lance position is lowered to 900-1000mm; after the oxygen blowing is completed, the time for soaking and corroding the residual slag layer of the furnace lining bricks is shortened from 10min to 5min, until the furnace lining bricks are exposed.

[0037] Furthermore, in step 4), if the slag splashing layer on the surface of the furnace lining brick is not completely removed and there is still some residue attached, and the furnace lining brick body is not exposed, repeat steps 1) to 3), wherein when the oxygen lance is at a position of 900 to 1000 mm, the oxygen blowing time is shortened from 5 min to 3 min; after the oxygen blowing is completed, the time for soaking and corroding the residual slag splashing layer of the furnace lining brick is shortened from 10 min to 5 min, until the furnace lining brick body is exposed.

[0038] Furthermore, in step (4), the step of cooling the furnace by water soaking is as follows: after the converter washing operation is completed, the high-temperature liquid slag in the furnace is turned over, the converter is shaken to zero position, and a steel water pipe with a smaller diameter than the inner diameter of the converter outlet is inserted from the outside to the inside of the converter outlet, with a diameter of 20 to 30 m. 3 / h of flow rate to inject cooling water into the furnace. When the injected cooling water flows out slightly from the steel outlet of the converter, close the cooling water inlet valve, stop injecting water, take out the steel water pipe, shut down the converter and keep it in a vertical state for a period of time, and forcefully cool the high-temperature furnace lining bricks after furnace washing. Under the influence of thermal expansion and contraction, it is beneficial to the peeling of residual slag layer and shortening the cooling time of high-temperature furnace lining bricks, which is convenient for the subsequent separation of furnace bottom and furnace body and dismantling of furnace. Finally, the cooling water in the furnace is collected by a slag pot from the furnace mouth on the slag pouring side of the converter, emptied several times, and the cooling work of the furnace is completed.

[0039] Furthermore, during the cooling process of the water-bubbling furnace, the temperature drop of the high-temperature furnace lining bricks and the static cooling time satisfy the following relationship (a):

[0040]

[0041] Where Δt is the temperature drop of high temperature furnace lining brick, °C; τ is the static cooling time, h.

[0042] The appropriate cooling time can be inferred from formula (a) to facilitate the subsequent separation of the furnace bottom and furnace body and the dismantling of the furnace. If the temperature of the high-temperature furnace lining bricks is to be reduced to 200-300°C after the furnace is washed, it can be calculated from formula (a) that the cooling time is 3.5-4 hours. After the converter is left to cool vertically for 3.5-4 hours, the cooling water in the furnace is collected from the furnace mouth on the slag pouring side of the converter using a slag pot, and emptied several times to complete the cooling work of the furnace.

[0043] Furthermore, in step (5), the furnace bottom and furnace body separation steps are as follows: first, the furnace bottom car is lifted to the slag tank car track under the converter by an overhead crane, and the slag tank car is dragged to the bottom of the furnace to be inspected; then, the hydraulic pump is turned on, and the top plate of the furnace bottom car is raised at a rate of 0.3 to 0.4 m / min by operating the lifting hydraulic cylinder. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, the hydraulic pressure of the hydraulic cylinder is maintained at 14 to 15 MPa to support the upright bottom of the converter; then, the weld of the flange surface connecting the furnace bottom and the furnace body and the furnace bottom pin are cut off; finally, the top plate of the furnace bottom car is lowered at a rate of 0.3 to 0.4 m / min. After the furnace bottom is separated from the furnace body by its own weight, the separated furnace bottom is transported out from the bottom of the furnace body.

[0044] Further, in step (6), the furnace lining brick removal step is:

[0045] i) Removal of furnace lining bricks from the furnace body: Swing the converter to 100-105° toward the steel-outlet side, so that the flange surface of the separated furnace body faces the working platform in front of the furnace, and remove the furnace lining bricks by ramming with a steel chisel from the furnace dismantling machine;

[0046] First, the furnace lining bricks on both sides of the horizontal axis of the furnace flange surface are grooved and rammed toward the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace flange surface are grooved and rammed toward the furnace mouth until they are rammed through. The semicircular furnace lining bricks on the furnace flange surface lose the mutual extrusion force, and the semicircular furnace lining bricks on the furnace flange surface can fall off by themselves under the action of their own gravity due to the vibration effect of the steel chisel of the furnace dismantling machine; if there are any semicircular furnace lining bricks on the furnace flange surface, they can be rammed with the steel chisel of the furnace dismantling machine to make them all fall off; then, tilt Move the converter to 180 degrees, turn the fallen furnace lining bricks from the furnace mouth to the slag pot under the furnace for recovery; finally, shake the converter to 100-105 degrees toward the steel-out side, and ram the furnace lining bricks from the vertical axis of the lower semicircle of the furnace body flange surface toward the furnace mouth in a slot-like manner. After ramming through, tilt the converter toward the slag-out side, so that the lower semicircle furnace lining bricks of the furnace body flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter; if there are any remaining furnace lining bricks in the lower semicircle of the furnace body flange surface, they can be rammed again with the steel chisel of the furnace dismantling machine to make them all fall off;

[0047] ii) Removal of furnace lining bricks at the bottom of the furnace:

[0048] The furnace bottom that is offline is transported to a safe place on the ground by an overhead crane. The furnace lining bricks at the offline furnace bottom are rammed with a steel chisel by a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, they are rammed and removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, they are turned over to create conditions for subsequent furnace bottom brick laying.

[0049] 3. Beneficial effects

[0050] Compared with the prior art, the method of the present invention has achieved the following implementation effects since its use:

[0051] (1) This method achieves the effect of quickly and evenly removing the slag layer attached to the surface of the furnace lining bricks by reasonably controlling the amount of slag left in the furnace when the furnace is shut down, using oxygen to react with the iron element in the slag reserved in the furnace, and reasonably controlling the oxygen pressure, oxygen flow, oxygen lance position, oxygen blowing time, and immersion and erosion time of the slag layer. The furnace washing operation time can be controlled within 30 minutes, avoiding steel leakage accidents during the furnace washing process, and creating conditions for the subsequent separation of the furnace bottom and the furnace body and the furnace dismantling operation;

[0052] (2) Before stopping the furnace, the height of the converter bottom and the residual thickness of the lining bricks at the weakest part of the converter are measured to provide references for the oxygen pressure, oxygen flow, lance position, oxygen blowing time, and immersion and erosion time of the slag splashing layer for furnace washing operation. By setting the oxygen pressure, oxygen flow, oxygen lance position, oxygen blowing time, and immersion and erosion time of the slag splashing layer in stages, the occurrence of steel leakage accidents during the furnace washing process is effectively prevented, and the effect of quickly and evenly removing the slag splashing layer attached to the surface of the furnace lining bricks is achieved, creating good conditions for the subsequent separation of the furnace bottom and the furnace body and the dismantling of the furnace;

[0053] (3) This method uses cooling water to inject into the furnace to forcefully cool the high-temperature furnace lining bricks after furnace washing. Under the influence of thermal expansion and contraction, it is beneficial to the peeling of the residual slag layer and shortening the cooling time of the high-temperature furnace lining bricks. Taking the residual thickness of the furnace lining bricks as 200-300mm and the height of the converter bottom as 100-200mm as an example, the cooling time of the furnace is only 4h, which can save 20h compared with the conventional natural cooling method which takes 24h;

[0054] (4) According to the characteristics of the active furnace bottom converter, after the furnace bottom is separated from the furnace body, the furnace lining bricks of the furnace body are removed by ramming from the axis of the furnace body flange surface to the furnace mouth, thereby destroying the mutual squeezing force between the furnace lining bricks. Under the action of their own weight, the furnace lining bricks can fall off by themselves. The removal time of the furnace lining bricks of the entire furnace body can be controlled within 6 hours, which greatly improves the work efficiency and reduces the labor intensity. The furnace lining bricks at the furnace bottom are removed offline, which almost does not take up the furnace inspection time and does not affect the entire furnace inspection cycle. When removing the furnace lining bricks at the furnace bottom, they are removed layer by layer starting from the center brick of the furnace bottom and ramming from top to bottom and from inside to outside, which is beneficial to protecting the furnace bottom steel structure and improving work efficiency.

[0055] (5) This method has the characteristics of high efficiency, low cost, safety, environmental protection, time saving and labor saving, and has good promotion and application prospects in the removal of lining bricks of active furnace bottom converters in similar steel enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the control of process parameters of the furnace washing operation of the present invention;

[0057] Figure 2The present invention is a schematic diagram of the operation flow of the method for efficiently removing lining bricks of a live bottom converter. DETAILED DESCRIPTION

[0058] The present invention is further described below in conjunction with specific embodiments and drawings, but they do not limit the present invention.

[0059] Example 1

[0060] (1) Measure the height of the converter bottom and the residual thickness of the converter lining bricks

[0061] After the 213-10935 furnace was tapped, the slag in the furnace was turned over. The Lacam M3 laser thickness gauge was used to measure the converter bottom height and the residual thickness of the converter lining bricks. The measured converter bottom height was 1073mm, which was 153mm relative to the 920mm new furnace bottom height. The residual thickness of the lining bricks at the weakest part of the converter body was 248mm.

[0062] (2) Preparation for shutdown

[0063] Furnace 213-10936 is planned to be shut down. When the molten steel is completely discharged from the furnace, the converter slag is tilted at an angle of 103° to pour out part of the slag. The amount of slag left in the furnace is controlled at 1.6t.

[0064] (3) Furnace cleaning operation

[0065] 1) After the slag pouring is completed, the converter is shaken to the zero position.

[0066] 2) Blow oxygen from the lower gun, set the oxygen pressure to 0.55MPa and the oxygen flow rate to 11000Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 5min.

[0067] 3) When the oxygen blowing time reaches 5 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 0.5min until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 5.5min, lower the oxygen lance position to 3500mm; when blowing oxygen for 6min, lower the oxygen lance position to 3000mm; when blowing oxygen for 6.5min, lower the oxygen lance position to 2500mm; when blowing oxygen for 7min, lower the oxygen lance position to 2000mm; when blowing oxygen for 7.5min, lower the oxygen lance position to 1500mm; when blowing oxygen for 8min, lower the oxygen lance position to 1000mm; continue blowing oxygen for 8.5min, raise the lance to the 6500mm waiting point and stop blowing oxygen.

[0068] 4) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 10 minutes.

[0069] 5) After the immersion erosion is completed, the converter is slowly shaken toward the slag pouring side, the slag pouring angle is 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splashing layer of the furnace lining brick from the front of the furnace mouth. At this time, the slag splashing layer on the surface of the furnace lining brick is not completely eroded, and the furnace lining brick is not exposed. Repeat steps 1) to 5).

[0070] 1-1) The converter is moved to zero position.

[0071] 2-1) Blow oxygen from the lower gun, set the oxygen pressure to 0.55MPa and the oxygen flow rate to 11000Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 3min.

[0072] 3-1) When the oxygen blowing time reaches 3 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 0.5min until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 3.5min, lower the oxygen lance position to 3500mm; when blowing oxygen for 4min, lower the oxygen lance position to 3000mm; when blowing oxygen for 4.5min, lower the oxygen lance position to 2500mm; when blowing oxygen for 5min, lower the oxygen lance position to 2000mm; when blowing oxygen for 5.5min, lower the oxygen lance position to 1500mm; when blowing oxygen for 6min, lower the oxygen lance position to 1000mm; continue blowing oxygen for 7.5min, raise the lance to the 6500mm waiting point, and stop blowing oxygen.

[0073] 4-1) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 5 minutes.

[0074] 5-1) After the immersion erosion is completed, the converter is slowly shaken toward the slag discharge side, with a slag discharge angle of 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splash layer of the furnace lining brick from the front of the furnace mouth. At this time, the slag splash layer on the surface of the furnace lining brick is completely eroded, and the furnace lining brick is exposed. The remaining 1 / 2 of the slag in the furnace is turned over, and the furnace washing operation is completed.

[0075] (4) Water-soaking furnace

[0076] The converter is swung to zero position, and a steel water pipe is inserted from the outside to the inside of the steel outlet. 3 / h flow rate of cooling water is injected into the furnace. When the injected cooling water flows out slightly from the steel outlet of the converter, close the cooling water inlet valve, stop injecting water, take out the steel water pipe, cut off the power supply of the converter and keep it in a vertical state. After cooling for 4 hours, the cooling water in the furnace is collected in a slag pot from the furnace mouth on the slag pouring side of the converter, and emptied in 6 times. The water-soaking furnace cooling work is completed.

[0077] (5) Separation of furnace bottom and furnace body

[0078] First, use an overhead crane to lift the furnace bottom car from the spare position to the slag tank car track under the converter, and then use the slag tank car to drag it to the bottom of the furnace to be inspected; then, start the hydraulic pump to raise the top plate of the furnace bottom car at a rate of 0.3m / min. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, maintain the hydraulic pressure of 14MPa to support the upright furnace bottom; then, cut off the flange surface welds connecting the furnace bottom and the furnace body, as well as the furnace bottom pins; finally, lower the top plate of the furnace bottom car at a rate of 0.3m / min. After the furnace bottom separates from the furnace body due to its own weight, the separated furnace bottom is transported out from under the furnace body, and then the offline furnace bottom is transported to the safe area on the ground by an overhead crane.

[0079] (6) Removal of furnace lining bricks

[0080] 1) Removal of furnace lining bricks in the furnace body

[0081] The converter is shaken to 103° toward the steel-outlet side so that the flange surface of the separated furnace body faces the working platform in front of the furnace. Firstly, the furnace dismantling machine steel chisel is used to groove and ram the furnace lining bricks on both sides of the horizontal axis of the furnace body flange surface towards the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface are grooved and rammed towards the furnace mouth. During the ramming process of the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface, the furnace lining bricks on the upper semicircular flange surface fall off by themselves under the action of their own gravity; then, the converter is tilted to 180°, and the fallen furnace lining bricks are turned over from the furnace mouth to the slag pot under the furnace for recovery; finally, the converter is shaken to 103° toward the steel-out side, and the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed toward the furnace mouth. After the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed through, the converter is tilted toward the slag-discharging side, so that the furnace lining bricks on the lower semicircular flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter.

[0082] 2) Removal of furnace lining bricks at the bottom of the furnace

[0083] After the furnace bottom is transported to a safe place on the ground by a crane, the furnace bottom bricks are removed by offline ramming with a steel chisel of a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, the bricks are removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, the furnace bottom bricks are turned over and the removal operation is completed. The removal time of the furnace lining bricks in this embodiment is about 11 hours.

[0084] Example 2

[0085] (1) Measure the height of the converter bottom and the residual thickness of the converter lining bricks

[0086] After the 211-17532 furnace was tapped, the slag in the furnace was turned over. The Lacam M3 laser thickness gauge was used to measure the converter bottom height and the residual thickness of the converter lining bricks. The measured converter bottom height was 1136mm, which was 216mm relative to the 920mm new furnace bottom height. The residual thickness of the lining bricks at the weakest part of the converter body was 112mm.

[0087] (2) Preparation for shutdown

[0088] Furnace 211-17533 is planned to be shut down. When the furnace has smelted all the molten steel, the converter slag will be tilted at an angle of 102° to pour out part of the slag. The amount of slag left in the furnace will be controlled at 1.5t.

[0089] (3) Furnace cleaning operation

[0090] 1) After the slag pouring is completed, the converter is shaken to the zero position.

[0091] 2) Blow oxygen from the lower gun, set the oxygen pressure to 0.45MPa and the oxygen flow rate to 10000Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 5min.

[0092] 3) When the oxygen blowing time reaches 5 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 20s until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 5 minutes and 20 seconds, lower the oxygen lance position to 3500mm; when blowing oxygen for 5 minutes and 40 seconds, lower the oxygen lance position to 3000mm; when blowing oxygen for 6 minutes, lower the oxygen lance position to 2500mm; when blowing oxygen for 6 minutes and 20 seconds, lower the oxygen lance position to 2000mm; when blowing oxygen for 6 minutes and 40 seconds, lower the oxygen lance position to 1500mm; when blowing oxygen for 7 minutes, lower the oxygen lance position to 1000mm; continue blowing oxygen for 7 minutes and 20 seconds, raise the lance to the 6500mm waiting point and stop blowing oxygen.

[0093] 4) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 12 minutes.

[0094] 5) After the immersion erosion is completed, the converter is slowly shaken toward the slag discharge side, with a slag discharge angle of 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splash layer of the furnace lining bricks from the front of the furnace mouth. At this time, the slag splash layer on the surface of the furnace lining bricks is completely eroded, and the furnace lining bricks are exposed. The remaining 1 / 2 of the slag in the furnace is turned over, and the furnace washing operation is completed.

[0095] (4) Water-soaking furnace

[0096] The converter is swung to zero position, and a steel water pipe is inserted from the outside to the inside of the steel outlet.3 / h flow rate of cooling water is injected into the furnace. When the injected cooling water flows out slightly from the steel outlet of the converter, close the cooling water inlet valve, stop injecting water, take out the steel water pipe, cut off the power supply of the converter and keep it in a vertical state. After cooling for 3.5h, the cooling water in the furnace is collected in a slag pot from the furnace mouth on the slag pouring side of the converter, emptied in 6 times, and the cooling work of the furnace is completed.

[0097] (5) Separation of furnace bottom and furnace body

[0098] First, use an overhead crane to lift the furnace bottom car from the spare position to the slag tank car track under the converter, and then use the slag tank car to drag it to the bottom of the furnace to be inspected; then, start the hydraulic pump to raise the top plate of the furnace bottom car at a rate of 0.3m / min. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, maintain the hydraulic pressure of 14MPa to support the upright furnace bottom; then, cut off the flange surface welds connecting the furnace bottom and the furnace body, as well as the furnace bottom pins; finally, lower the top plate of the furnace bottom car at a rate of 0.3m / min. After the furnace bottom separates from the furnace body due to its own weight, the separated furnace bottom is transported out from under the furnace body, and then the offline furnace bottom is transported to the safe area on the ground by an overhead crane.

[0099] (6) Removal of furnace lining bricks

[0100] 1) Removal of furnace lining bricks in the furnace body

[0101] The converter is shaken to 103° toward the steel-outlet side so that the flange surface of the separated furnace body faces the working platform in front of the furnace. Firstly, the furnace dismantling machine steel chisel is used to groove and ram the furnace lining bricks on both sides of the horizontal axis of the furnace body flange surface towards the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface are grooved and rammed towards the furnace mouth. During the ramming process of the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface, the furnace lining bricks on the upper semicircular flange surface fall off by themselves under the action of their own gravity; then, the converter is tilted to 180°, and the fallen furnace lining bricks are turned over from the furnace mouth to the slag pot under the furnace for recovery; finally, the converter is shaken to 103° toward the steel-out side, and the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed toward the furnace mouth. After the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed through, the converter is tilted toward the slag-discharging side, so that the furnace lining bricks on the lower semicircular flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter.

[0102] 2) Removal of furnace lining bricks at the bottom of the furnace

[0103] After the furnace bottom is transported to a safe place on the ground by a crane, the furnace bottom bricks are removed by offline ramming with a steel chisel of a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, the furnace bottom bricks are removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, the furnace bottom bricks are turned over and the removal operation is completed. The removal time of the furnace lining bricks in this embodiment is about 10 hours and 20 minutes.

[0104] Example 3

[0105] (1) Measure the height of the converter bottom and the residual thickness of the converter lining bricks

[0106] After the 214-10837 furnace was tapped, the slag in the furnace was turned over. The Lacam M3 laser thickness gauge was used to measure the converter bottom height and the residual thickness of the converter lining bricks. The measured converter bottom height was 973mm, which was 53mm relative to the 920mm new furnace bottom height. The residual thickness of the lining bricks at the weakest part of the converter body was 332mm.

[0107] (2) Preparation for shutdown

[0108] Furnace 214-10838 is planned to be shut down. After the molten steel is completely discharged from the furnace, the converter slag is tilted at an angle of 103° to pour out part of the slag. The amount of slag left in the furnace is controlled at 1.7t.

[0109] (3) Furnace cleaning operation

[0110] 1) After the slag pouring is completed, the converter is shaken to the zero position.

[0111] 2) Blow oxygen from the lower gun, set the oxygen pressure to 0.65MPa and the oxygen flow rate to 12500Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 5min.

[0112] 3) When the oxygen blowing time reaches 5 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 40s until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 5 minutes and 40 seconds, lower the oxygen lance position to 3500mm; when blowing oxygen for 6 minutes and 20 seconds, lower the oxygen lance position to 3000mm; when blowing oxygen for 7 minutes, lower the oxygen lance position to 2500mm; when blowing oxygen for 7 minutes and 40 seconds, lower the oxygen lance position to 2000mm; when blowing oxygen for 8 minutes and 20 seconds, lower the oxygen lance position to 1500mm; when blowing oxygen for 9 minutes, lower the oxygen lance position to 1000mm; continue blowing oxygen for 9 minutes and 40 seconds, raise the lance to the 6500mm waiting point, and stop blowing oxygen.

[0113] 4) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 8 minutes.

[0114] 5) After the immersion erosion is completed, the converter is slowly shaken toward the slag pouring side, the slag pouring angle is 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splashing layer of the furnace lining brick from the front of the furnace mouth. At this time, the slag splashing layer on the surface of the furnace lining brick is not completely eroded, and the furnace lining brick is not exposed. Repeat steps 1) to 5).

[0115] 1-1) The converter is moved to zero position.

[0116] 2-1) Blow oxygen from the lower gun, set the oxygen pressure to 0.65MPa and the oxygen flow rate to 12500Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 3min.

[0117] 3-1) When the oxygen blowing time reaches 3 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 40s until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 3 minutes and 40 seconds, lower the oxygen lance position to 3500mm; when blowing oxygen for 4 minutes and 20 seconds, lower the oxygen lance position to 3000mm; when blowing oxygen for 5 minutes, lower the oxygen lance position to 2500mm; when blowing oxygen for 5 minutes and 40 seconds, lower the oxygen lance position to 2000mm; when blowing oxygen for 6 minutes and 20 seconds, lower the oxygen lance position to 1500mm; when blowing oxygen for 7 minutes, lower the oxygen lance position to 1000mm; continue blowing oxygen for 7 minutes and 40 seconds, raise the lance to the 6500mm waiting point, and stop blowing oxygen.

[0118] 4-1) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 4 minutes.

[0119] 5-1) After the immersion erosion is completed, the converter is slowly shaken toward the slag discharge side, with a slag discharge angle of 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splash layer of the furnace lining brick from the front of the furnace mouth. At this time, the slag splash layer on the surface of the furnace lining brick is completely eroded, and the furnace lining brick is exposed. The remaining 1 / 2 of the slag in the furnace is turned over, and the furnace washing operation is completed.

[0120] (4) Water-soaking furnace

[0121] The converter is swung to zero position, and a steel water pipe is inserted from the outside to the inside of the steel outlet. 3 / h flow rate of cooling water is injected into the furnace. When the injected cooling water flows out slightly from the steel outlet of the converter, close the cooling water inlet valve, stop injecting water, take out the steel water pipe, cut off the power supply of the converter and keep it in a vertical state. After cooling for 4 hours, the cooling water in the furnace is collected in a slag pot from the furnace mouth on the slag pouring side of the converter, and emptied in 6 times. The water-soaking furnace cooling work is completed.

[0122] (5) Separation of furnace bottom and furnace body

[0123] First, use an overhead crane to lift the furnace bottom car from the spare position to the slag tank car track under the converter, and then use the slag tank car to drag it to the bottom of the furnace to be inspected; then, start the hydraulic pump to raise the top plate of the furnace bottom car at a rate of 0.3m / min. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, maintain the hydraulic pressure of 14MPa to support the upright furnace bottom; then, cut off the flange surface welds connecting the furnace bottom and the furnace body, as well as the furnace bottom pins; finally, lower the top plate of the furnace bottom car at a rate of 0.3m / min. After the furnace bottom separates from the furnace body due to its own weight, the separated furnace bottom is transported out from under the furnace body, and then the offline furnace bottom is transported to the safe area on the ground by an overhead crane.

[0124] (6) Removal of furnace lining bricks

[0125] 1) Removal of furnace lining bricks in the furnace body

[0126] The converter is shaken to 103° toward the steel-outlet side so that the flange surface of the separated furnace body faces the working platform in front of the furnace. Firstly, the furnace dismantling machine steel chisel is used to groove and ram the furnace lining bricks on both sides of the horizontal axis of the furnace body flange surface towards the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface are grooved and rammed towards the furnace mouth. During the ramming process of the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface, the furnace lining bricks on the upper semicircular flange surface fall off by themselves under the action of their own gravity; then, the converter is tilted to 180°, and the fallen furnace lining bricks are turned over from the furnace mouth to the slag pot under the furnace for recovery; finally, the converter is shaken to 103° toward the steel-out side, and the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed toward the furnace mouth. After the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed through, the converter is tilted toward the slag-discharging side, so that the furnace lining bricks on the lower semicircular flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter.

[0127] 2) Removal of furnace lining bricks at the bottom of the furnace

[0128] After the furnace bottom is transported to a safe place on the ground by a crane, the furnace bottom bricks are removed by offline ramming with a steel chisel of a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, the furnace bottom bricks are removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, the furnace bottom bricks are turned over and the removal operation is completed. The removal time of the furnace lining bricks in this embodiment is about 10 hours and 30 minutes.

[0129] Example 4

[0130] (1) Measure the height of the converter bottom and the residual thickness of the converter lining bricks

[0131] After the 212-11354 furnace was tapped, the slag in the furnace was turned over. The Lacam M3 laser thickness gauge was used to measure the converter bottom height and the residual thickness of the converter lining bricks. The measured converter bottom height was 875mm, which was -45mm relative to the 920mm new furnace bottom height. The residual thickness of the lining bricks at the weakest part of the converter body was 232mm.

[0132] (2) Preparation for shutdown

[0133] Furnace 212-11355 is planned to be shut down. After the molten steel is completely discharged from the furnace, the converter will be tilted to 103° to pour out part of the slag. The amount of slag left in the furnace will be controlled at 1.4t.

[0134] (3) Furnace cleaning operation

[0135] 1) After the slag pouring is completed, the converter is shaken to the zero position.

[0136] 2) Blow oxygen from the lower gun, set the oxygen pressure to 0.55MPa and the oxygen flow rate to 11000Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 5min.

[0137] 3) When the oxygen blowing time reaches 5 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 30s until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 5 minutes and 30 seconds, lower the oxygen lance position to 3500mm; when blowing oxygen for 6 minutes, lower the oxygen lance position to 3000mm; when blowing oxygen for 6 minutes and 30 seconds, lower the oxygen lance position to 2500mm; when blowing oxygen for 7 minutes, lower the oxygen lance position to 2000mm; when blowing oxygen for 7 minutes and 30 seconds, lower the oxygen lance position to 1500mm; when blowing oxygen for 8 minutes, lower the oxygen lance position to 1000mm; continue blowing oxygen for 8 minutes and 30 seconds, raise the lance to the 6500mm waiting point and stop blowing oxygen.

[0138] 4) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 6 minutes.

[0139] 5) After the immersion erosion is completed, the converter is slowly shaken toward the slag pouring side, the slag pouring angle is 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splashing layer of the furnace lining brick from the front of the furnace mouth. At this time, the slag splashing layer on the surface of the furnace lining brick is not completely eroded, and the furnace lining brick is not exposed. Repeat steps 1) to 5).

[0140] 1-1) The converter is moved to zero position.

[0141] 2-1) Blow oxygen from the lower gun, set the oxygen pressure to 0.55MPa and the oxygen flow rate to 11000Nm3 / h, oxygen lance position 1000mm, oxygen blowing time 3min.

[0142] 3-1) When the oxygen blowing time reaches 3 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 30s until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 3 minutes and 30 seconds, lower the oxygen lance position to 3500mm; when blowing oxygen for 4 minutes, lower the oxygen lance position to 3000mm; when blowing oxygen for 4 minutes and 30 seconds, lower the oxygen lance position to 2500mm; when blowing oxygen for 5 minutes, lower the oxygen lance position to 2000mm; when blowing oxygen for 5 minutes and 30 seconds, lower the oxygen lance position to 1500mm; when blowing oxygen for 6 minutes, lower the oxygen lance position to 1000mm; continue blowing oxygen for 6 minutes and 30 seconds, raise the lance to the 6500mm waiting point and stop blowing oxygen.

[0143] 4-1) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 3 minutes.

[0144] 5-1) After the immersion erosion is completed, the converter is slowly shaken toward the slag discharge side, with a slag discharge angle of 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splash layer of the furnace lining brick from the front of the furnace mouth. At this time, the slag splash layer on the surface of the furnace lining brick is completely eroded, and the furnace lining brick is exposed. The remaining 1 / 2 of the slag in the furnace is turned over, and the furnace washing operation is completed.

[0145] (4) Water-soaking furnace

[0146] The converter is swung to zero position, and a steel water pipe is inserted from the outside to the inside of the steel outlet. 3 / h flow rate of cooling water is injected into the furnace. When the injected cooling water flows out slightly from the steel outlet of the converter, close the cooling water inlet valve, stop injecting water, take out the steel water pipe, cut off the power supply of the converter and keep it in a vertical state. After cooling for 3.8h, the cooling water in the furnace is collected in a slag pot from the furnace mouth on the slag pouring side of the converter, and emptied in 6 times. The cooling work of the furnace is completed.

[0147] (5) Separation of furnace bottom and furnace body

[0148] First, use an overhead crane to lift the furnace bottom car from the spare position to the slag tank car track under the converter, and then use the slag tank car to drag it to the bottom of the furnace to be inspected; then, start the hydraulic pump to raise the top plate of the furnace bottom car at a rate of 0.3m / min. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, maintain the hydraulic pressure of 14MPa to support the upright furnace bottom; then, cut off the flange surface welds connecting the furnace bottom and the furnace body, as well as the furnace bottom pins; finally, lower the top plate of the furnace bottom car at a rate of 0.3m / min. After the furnace bottom separates from the furnace body due to its own weight, the separated furnace bottom is transported out from under the furnace body, and then the offline furnace bottom is transported to the safe area on the ground by an overhead crane.

[0149] (6) Removal of furnace lining bricks

[0150] 1) Removal of furnace lining bricks in the furnace body

[0151] The converter is shaken to 103° toward the steel-outlet side so that the flange surface of the separated furnace body faces the working platform in front of the furnace. Firstly, the furnace dismantling machine steel chisel is used to groove and ram the furnace lining bricks on both sides of the horizontal axis of the furnace body flange surface towards the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface are grooved and rammed towards the furnace mouth. During the ramming process of the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface, the furnace lining bricks on the upper semicircular flange surface fall off by themselves under the action of their own gravity; then, the converter is tilted to 180°, and the fallen furnace lining bricks are turned over from the furnace mouth to the slag pot under the furnace for recovery; finally, the converter is shaken to 103° toward the steel-out side, and the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed toward the furnace mouth. After the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed through, the converter is tilted toward the slag-discharging side, so that the furnace lining bricks on the lower semicircular flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter.

[0152] 2) Removal of furnace lining bricks at the bottom of the furnace

[0153] After the furnace bottom is transported to a safe place on the ground by a crane, the furnace bottom bricks are removed by offline ramming with a steel chisel of a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, the furnace bottom bricks are removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, the furnace bottom bricks are turned over and the removal operation is completed. The removal time of the furnace lining bricks in this embodiment is about 10 hours and 25 minutes.

[0154] Example 5

[0155] (1) Measure the height of the converter bottom and the residual thickness of the converter lining bricks

[0156] After the 222-15789 furnace was tapped, the slag in the furnace was turned over. The Lacam M3 laser thickness gauge was used to measure the converter bottom height and the residual thickness of the converter lining bricks. The measured converter bottom height was 784mm, which was -136mm relative to the 920mm new furnace bottom height. The residual thickness of the lining bricks at the weakest part of the converter body was 212mm.

[0157] (2) Preparation for shutdown

[0158] Furnace 222-15790 is planned to be shut down. After the molten steel is completely discharged from the furnace, the converter slag will be tilted at an angle of 103° to pour out part of the slag. The amount of slag left in the furnace will be controlled at 1.5t.

[0159] (3) Furnace cleaning operation

[0160] 1) After the slag pouring is completed, the converter is shaken to the zero position.

[0161] 2) Blow oxygen from the lower gun, set the oxygen pressure to 0.55MPa and the oxygen flow rate to 11000Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 5min.

[0162] 3) When the oxygen blowing time reaches 5 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 30s until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 5 minutes and 30 seconds, lower the oxygen lance position to 3500mm; when blowing oxygen for 6 minutes, lower the oxygen lance position to 3000mm; when blowing oxygen for 6 minutes and 30 seconds, lower the oxygen lance position to 2500mm; when blowing oxygen for 7 minutes, lower the oxygen lance position to 2000mm; when blowing oxygen for 7 minutes and 30 seconds, lower the oxygen lance position to 1500mm; when blowing oxygen for 8 minutes, lower the oxygen lance position to 1000mm; continue blowing oxygen for 8 minutes and 30 seconds, raise the lance to the 6500mm waiting point and stop blowing oxygen.

[0163] 4) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 5 minutes.

[0164] 5) After the immersion erosion is completed, the converter is slowly shaken toward the slag discharge side, with a slag discharge angle of 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splash layer of the furnace lining bricks from the front of the furnace mouth. At this time, the slag splash layer on the surface of the furnace lining bricks is completely eroded, and the furnace lining bricks are exposed. The remaining 1 / 2 of the slag in the furnace is turned over, and the furnace washing operation is completed.

[0165] (4) Water-soaking furnace

[0166] The converter is swung to zero position, and a steel water pipe is inserted from the outside to the inside of the steel outlet.3 / h flow rate of cooling water is injected into the furnace. When the injected cooling water flows out slightly from the steel outlet of the converter, close the cooling water inlet valve, stop injecting water, take out the steel water pipe, cut off the power supply of the converter and keep it in a vertical state. After cooling for 3.6 hours, the cooling water in the furnace is collected in a slag pot from the furnace mouth on the slag pouring side of the converter, emptied in 6 times, and the cooling work of the furnace is completed.

[0167] (5) Separation of furnace bottom and furnace body

[0168] First, use an overhead crane to lift the furnace bottom car from the spare position to the slag tank car track under the converter, and then use the slag tank car to drag it to the bottom of the furnace to be inspected; then, start the hydraulic pump to raise the top plate of the furnace bottom car at a rate of 0.3m / min. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, maintain the hydraulic pressure of 14MPa to support the upright furnace bottom; then, cut off the flange surface welds connecting the furnace bottom and the furnace body, as well as the furnace bottom pins; finally, lower the top plate of the furnace bottom car at a rate of 0.3m / min. After the furnace bottom separates from the furnace body due to its own weight, the separated furnace bottom is transported out from under the furnace body, and then the offline furnace bottom is transported to the safe area on the ground by an overhead crane.

[0169] (6) Removal of furnace lining bricks

[0170] 1) Removal of furnace lining bricks in the furnace body

[0171] The converter is shaken to 103° toward the steel-outlet side so that the flange surface of the separated furnace body faces the working platform in front of the furnace. Firstly, the furnace dismantling machine steel chisel is used to groove and ram the furnace lining bricks on both sides of the horizontal axis of the furnace body flange surface towards the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface are grooved and rammed towards the furnace mouth. During the ramming process of the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface, the furnace lining bricks on the upper semicircular flange surface fall off by themselves under the action of their own gravity; then, the converter is tilted to 180°, and the fallen furnace lining bricks are turned over from the furnace mouth to the slag pot under the furnace for recovery; finally, the converter is shaken to 103° toward the steel-out side, and the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed toward the furnace mouth. After the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed through, the converter is tilted toward the slag-discharging side, so that the furnace lining bricks on the lower semicircular flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter.

[0172] 2) Removal of furnace lining bricks at the bottom of the furnace

[0173] After the furnace bottom is transported to a safe place on the ground by a crane, the furnace bottom bricks are removed by offline ramming with a steel chisel of a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, the bricks are removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, the furnace bottom bricks are turned over and the removal operation is completed. The removal time of the furnace lining bricks in this embodiment is about 10 hours and 15 minutes.

[0174] Example 6

[0175] (1) Measure the height of the converter bottom and the residual thickness of the converter lining bricks

[0176] After the 223-14256 furnace was tapped, the slag in the furnace was turned over. The Lacam M3 laser thickness gauge was used to measure the converter bottom height and the residual thickness of the converter lining bricks. The measured converter bottom height was 704mm, which was -216mm relative to the 920mm new furnace bottom height. The residual thickness of the lining bricks at the weakest part of the converter body was 327mm.

[0177] (2) Preparation for shutdown

[0178] Furnace 223-14257 is planned to be shut down. After the molten steel is completely discharged from the furnace, the converter slag is tilted at an angle of 102° to pour out part of the slag. The amount of slag left in the furnace is controlled at 1.6t.

[0179] (3) Furnace cleaning operation

[0180] 1) After the slag pouring is completed, the converter is shaken to the zero position.

[0181] 2) Blow oxygen from the lower gun, set the oxygen pressure to 0.65MPa and the oxygen flow rate to 12500Nm 3 / h, oxygen lance position 1000mm, oxygen blowing time 5min.

[0182] 3) When the oxygen blowing time reaches 5 minutes, set the oxygen pressure to 0.35MPa and the oxygen flow rate to 6600Nm 3 / h, raise the oxygen lance position to 4000mm. Continue blowing oxygen by lowering the oxygen lance position by 500mm every 40s until the oxygen lance position drops to 1000mm, that is, when blowing oxygen for 5 minutes and 40 seconds, lower the oxygen lance position to 3500mm; when blowing oxygen for 6 minutes and 20 seconds, lower the oxygen lance position to 3000mm; when blowing oxygen for 7 minutes, lower the oxygen lance position to 2500mm; when blowing oxygen for 7 minutes and 40 seconds, lower the oxygen lance position to 2000mm; when blowing oxygen for 8 minutes and 20 seconds, lower the oxygen lance position to 1500mm; when blowing oxygen for 9 minutes, lower the oxygen lance position to 1000mm; continue blowing oxygen for 9 minutes and 40 seconds, raise the lance to the 6500mm waiting point, and stop blowing oxygen.

[0183] 4) After the oxygen blowing is completed, the converter is kept at zero position and the slag splash layer attached to the surface of the converter lining bricks is soaked and corroded for 4 minutes.

[0184] 5) After the immersion erosion is completed, the converter is slowly shaken toward the slag discharge side, with a slag discharge angle of 100°, and 1 / 2 of the slag is poured out. After the converter stops steadily, the operator observes the erosion of the slag splash layer of the furnace lining bricks from the front of the furnace mouth. At this time, the slag splash layer on the surface of the furnace lining bricks is completely eroded, and the furnace lining bricks are exposed. The remaining 1 / 2 of the slag in the furnace is turned over, and the furnace washing operation is completed.

[0185] (4) Water-soaking furnace

[0186] The converter is swung to zero position, and a steel water pipe is inserted from the outside to the inside of the steel outlet. 3 / h flow rate of cooling water is injected into the furnace. When the injected cooling water flows out slightly from the steel outlet of the converter, close the cooling water inlet valve, stop injecting water, take out the steel water pipe, cut off the power supply of the converter and keep it in a vertical state. After cooling for 4 hours, the cooling water in the furnace is collected in a slag pot from the furnace mouth on the slag pouring side of the converter, and emptied in 6 times. The water-soaking furnace cooling work is completed.

[0187] (5) Separation of furnace bottom and furnace body

[0188] First, use an overhead crane to lift the furnace bottom car from the spare position to the slag tank car track under the converter, and then use the slag tank car to drag it to the bottom of the furnace to be inspected; then, start the hydraulic pump to raise the top plate of the furnace bottom car at a rate of 0.3m / min. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, maintain the hydraulic pressure of 14MPa to support the upright furnace bottom; then, cut off the flange surface welds connecting the furnace bottom and the furnace body, as well as the furnace bottom pins; finally, lower the top plate of the furnace bottom car at a rate of 0.3m / min. After the furnace bottom separates from the furnace body due to its own weight, the separated furnace bottom is transported out from under the furnace body, and then the offline furnace bottom is transported to the safe area on the ground by an overhead crane.

[0189] (6) Removal of furnace lining bricks

[0190] 1) Removal of furnace lining bricks in the furnace body

[0191] The converter is shaken to 103° toward the steel-outlet side so that the flange surface of the separated furnace body faces the working platform in front of the furnace. Firstly, the furnace dismantling machine steel chisel is used to groove and ram the furnace lining bricks on both sides of the horizontal axis of the furnace body flange surface towards the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface are grooved and rammed towards the furnace mouth. During the ramming process of the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface, the furnace lining bricks on the upper semicircular flange surface fall off by themselves under the action of their own gravity; then, the converter is tilted to 180°, and the fallen furnace lining bricks are turned over from the furnace mouth to the slag pot under the furnace for recovery; finally, the converter is shaken to 103° toward the steel-out side, and the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed toward the furnace mouth. After the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are rammed through, the converter is tilted toward the slag-discharging side, so that the furnace lining bricks on the lower semicircular flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter.

[0192] 2) Removal of furnace lining bricks at the bottom of the furnace

[0193] After the furnace bottom is transported to a safe place on the ground by a crane, the furnace bottom bricks are removed by offline ramming with a steel chisel of a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, the furnace bottom bricks are removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, the furnace bottom bricks are turned over and the removal operation is completed. The removal time of the furnace lining bricks in this embodiment is about 10 hours and 14 minutes.

[0194] The examples described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should all fall within the protection scope of the present invention.

Claims

1. A method for efficiently removing lining bricks of a live bottom converter, characterized in that: The following steps are involved: (1) Measure the residual thickness of converter lining bricks and the height of converter bottom; (2) Preparation for shutdown; (3) Furnace washing operation: The method of oxygen blowing furnace washing is adopted, wherein: The corresponding relationship between the residual thickness of the furnace lining bricks and the oxygen pressure, flow rate and oxygen blowing time is: The corresponding relationship between the converter bottom height and the immersion erosion slag splashing layer time is: The specific steps of furnace washing operation are: 1) The converter is shaken to zero position, oxygen is blown from the lower lance, and the oxygen lance position is 900-1000mm; 2) When the oxygen blowing time reaches 5 minutes, raise the oxygen lance position to 3900-4000mm, and lower the lance position by 500-600mm at regular intervals to carry out oxygen blowing operation until the oxygen lance position is lowered to 900-1000mm; 3) When the oxygen blowing time reaches 8.5 minutes, lift the gun to the waiting point of 6500mm and stop blowing oxygen; keep the converter at zero position, soak and erode the residual splashing slag layer attached to the surface of the furnace lining bricks for 10 minutes, then tilt the converter at an angle of 100-102°, pour out 1 / 2 of the total amount of slag in the furnace, and observe the removal of the splashing slag layer on the surface of the furnace lining bricks; 4) If the slag splashing layer on the surface of the furnace lining brick is completely removed and the furnace lining brick body is exposed, the furnace cleaning operation is completed; if the slag splashing layer on the surface of the furnace lining brick is not completely removed and there is still some residue attached, and the furnace lining brick body is not exposed, repeat steps 1) to 3); (4) Cool the furnace with water; (5) The furnace bottom and the furnace body are separated; (6) Removal of furnace lining bricks.

2. The method for efficiently removing lining bricks of a live bottom converter according to claim 1, characterized in that: In step (1), a Lacam M3 laser thickness gauge is used to measure the residual thickness of the converter lining bricks and the height of the converter bottom.

3. The method for efficiently removing lining bricks of a movable bottom converter according to claim 1, characterized in that: In step (2), the furnace is shut down for a period of time. When the molten steel in the furnace is smelted normally and all the molten steel is discharged, the converter is tilted toward the slag discharge side to discharge part of the slag in the furnace. The amount of slag left is controlled at 20-30 kg / t steel.

4. The method for efficiently removing lining bricks of a live bottom converter according to claim 3, characterized in that: In step (2), the angle of slag pouring in the converter is 100 to 105°.

5. The method for efficiently removing lining bricks of a live bottom converter according to claim 1, characterized in that: In step 4), if the slag layer on the surface of the furnace lining brick is not completely removed and there is still some residue attached, and the furnace lining brick body is not exposed, repeat steps 1) to 3), wherein when the oxygen lance is at a position of 900 to 1000 mm, the oxygen blowing time is shortened from 5 min to 3 min; after the oxygen blowing is completed, the time for soaking and corroding the residual slag layer of the furnace lining brick is shortened from 10 min to 5 min, until the furnace lining brick body is exposed.

6. The method for efficiently removing lining bricks of a live hearth converter according to claim 1, characterized in that: In step (4), the step of cooling the furnace by water soaking is as follows: after the converter washing operation is completed, the high-temperature liquid slag in the furnace is turned over, the converter is shaken to zero position, and a steel water pipe with a smaller diameter than the inner diameter of the converter outlet is inserted from the outside to the inside of the converter outlet, with a diameter of 20 to 30 m. 3 / h of flow rate is injected into the furnace. When the injected cooling water flows out from the steel outlet of the converter, the cooling water inlet valve is closed, the water injection is stopped, the steel water pipe is taken out, the converter is powered off and kept in a vertical state for a period of time to force cooling of the high-temperature furnace lining bricks after furnace washing; finally, the cooling water in the furnace is collected in a slag pot from the furnace outlet on the slag pouring side of the converter, emptied several times, and the water-soaking furnace cooling work is completed.

7. The method for efficiently removing lining bricks of a live bottom converter according to claim 6, characterized in that: During the cooling process of the water-bubbling furnace, the temperature drop of the high-temperature furnace lining bricks and the static cooling time satisfy the following relationship (a): Where Δt is the temperature drop of high temperature furnace lining brick, °C; τ is the static cooling time, h.

8. The method for efficiently removing lining bricks of a live bottom converter according to claim 1, characterized in that: In step (5), the furnace bottom and furnace body separation steps are as follows: first, the furnace bottom car is lifted to the slag tank car track under the converter by an overhead crane, and the slag tank car is dragged to the bottom of the furnace to be inspected; then, the hydraulic pump is turned on, and the top plate of the furnace bottom car is raised at a rate of 0.3-0.4 m / min by operating the lifting hydraulic cylinder. When the center of the top plate of the furnace bottom car touches the center of the bottom of the converter to be inspected, the hydraulic pressure of the hydraulic cylinder is maintained at 14-15 MPa to support the upright bottom of the converter; then, the weld of the flange surface connecting the furnace bottom and the furnace body and the furnace bottom pin are cut off; finally, the top plate of the furnace bottom car is lowered at a rate of 0.3-0.4 m / min. After the furnace bottom is separated from the furnace body by its own weight, the separated furnace bottom is transported out from the bottom of the furnace body.

9. The method for efficiently removing lining bricks of a live hearth converter according to claim 1, characterized in that: In step (6), the furnace lining brick removal steps are: i) Removal of furnace lining bricks from the furnace body: Swing the converter to 100-105° toward the steel-outlet side, so that the flange surface of the separated furnace body faces the working platform in front of the furnace, and remove the furnace lining bricks by ramming with a steel chisel from the furnace dismantling machine; First, the furnace lining bricks on both sides of the horizontal axis of the furnace body flange surface are grooved and rammed toward the furnace mouth until the furnace lining bricks on both sides are rammed through; then, the furnace lining bricks on the upper semicircular vertical axis of the furnace body flange surface are grooved and rammed toward the furnace mouth until they are rammed through; if there are any remaining semicircular furnace lining bricks on the furnace body flange surface, they can be rammed with a steel chisel of a furnace dismantling machine to make them all fall off; then, the converter is tilted to 180°, and the fallen furnace lining bricks are turned over from the furnace mouth to the slag pot under the furnace for recovery; finally, the converter is shaken to 100-105° toward the steel tapping side, and the furnace lining bricks on the lower semicircular vertical axis of the furnace body flange surface are grooved and rammed toward the furnace mouth. After ramming through, the converter is tilted toward the slag pouring side, so that the lower semicircular furnace lining bricks on the furnace body flange surface fall off by themselves under the action of their own gravity during the tilting process of the converter; if there are any remaining semicircular furnace lining bricks on the lower semicircular furnace body flange surface, they can be rammed again with a steel chisel of a furnace dismantling machine to make them all fall off; ii) Removal of furnace lining bricks at the bottom of the furnace: The furnace bottom that is offline is transported to a safe place on the ground by an overhead crane, and the furnace lining bricks at the offline furnace bottom are rammed with a steel chisel by a furnace dismantling machine. Starting from the center brick of the furnace bottom flange surface, the bricks are rammed and removed layer by layer from top to bottom and from inside to outside. After all the furnace bottom bricks are crushed, the furnace bottom bricks are turned over.

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