A method for quickly and effectively treating the build-up in the hearth of a blast furnace

Abstract

The application discloses a method for quickly and effectively treating the accumulation of a blast furnace hearth. The method combines manganese ore furnace washing, large air volume, small ore batch, full coke, concentrated addition of circulating clean coke, and material distribution adjustment, clearly defines the ore batch and load during the furnace washing, adjusts the material distribution, controls the [Si] and [Mn] of the molten iron, the (MnO) in the slag, the physical heat, the binary basicity, the water temperature difference, the air volume usage, the number of air supply tuyeres, the addition amount and addition mode of the manganese ore at different stages, and other operations, so that the accumulation of the hearth can be eliminated and the furnace condition can be restored to the normal level in only 3-10 days.

Description

Technical Field

[0001] This invention belongs to the field of blast furnace smelting technology, specifically relating to a method for rapidly and effectively treating blast furnace hearth buildup. Background Technology

[0002] The blast furnace hearth primarily contains molten slag, iron, and coke. The coke deadweight column is immersed in the molten iron, and the pores of the coke column are filled with molten slag and iron. Hearth accumulation is classified into two types based on its location: center accumulation and edge accumulation. Based on the cause of accumulation, it can be categorized into graphite carbon accumulation, basic binder accumulation, furnace cooling accumulation, and accumulation of mixtures of TiC, TiN, and their solid solutions Ti(C,N). Regardless of the form of hearth accumulation, it is caused by long-term unreasonable basic operating procedures in blast furnace operation. Due to changes in raw materials, fuels, and equipment factors, the blast furnace operation cannot adapt in a timely manner, causing the furnace condition to gradually change from normal to abnormal, and further develop into malfunction.

[0003] Blast furnace hearth buildup is equivalent to a reduction in the hearth diameter and effective working space, making it unable to accommodate newly produced slag and iron. This leads to a slowdown in slag and iron circulation within the hearth, resulting in a gradual decrease in hearth activity. Consequently, this causes significant fluctuations in the blast furnace thermal regime, turbulent initial gas flow, asymmetry between blast volume and pressure, rejection of blast volume, large pressure differential fluctuations, uneven charging, and abnormal slag and iron discharge. The entire stable operation of the blast furnace is disrupted, with frequent occurrences of pipework slippage and suspended material. Without effective recovery measures, this can easily develop into hearth freezing. Blast furnace output and performance indicators decline sharply, while costs increase significantly. How to quickly handle hearth buildup after it occurs is a problem that ironmaking workers are constantly concerned with and researching.

[0004] Conventional methods for dealing with slag buildup include reducing blast, decreasing ore volume, reducing load, and blocking tuyeres. Large amounts of substances that lower the slag melting point, such as fluorite, manganese ore, soaking slag, and new metallizing burdens, are added. However, the amount and method of addition, as well as adjustments to blast furnace operation, vary widely, resulting in long recovery periods for blast furnaces. Small and medium-sized blast furnaces typically require 10-15 days, while large blast furnaces, depending on the severity of the deterioration, can have recovery periods ranging from several weeks to a year, leading to a significant decline in blast furnace output and performance indicators, and a substantial increase in costs. Although manganese ore washing is a common method for dealing with hearth buildup in the industry, the amount and method of addition, as well as the adjustments made to the blast furnace in conjunction with washing, vary widely. There are no clearly defined and reasonable control targets, and the adjustments to blast furnace operation in conjunction with washing result in long recovery periods for blast furnace hearth buildup.

[0005] To address the aforementioned problems, this invention aims to provide a rapid and effective method for handling furnace hearth buildup. Summary of the Invention

[0006] The purpose of this invention is to provide a method for quickly and effectively dealing with blast furnace hearth buildup.

[0007] The objective of this invention is achieved by providing a rapid and effective method for treating blast furnace hearth buildup, implemented through the following steps:

[0008] 1) Reduce the ore batch size to 85% of the batch size for furnace operation, and reduce the total coke load to 2.88 times;

[0009] 2) After reducing the full coke load, use the method of adding clean coke in cycles every nine to ten days;

[0010] 3) The Si content of molten iron is controlled at 1.0±0.2% and the physical heat is controlled at 1500±20℃ by adjusting the humidification amount and air temperature. The binary basicity is controlled at 1.09±0.01 times by adjusting the ore ratio.

[0011] 4) Adopt a material distribution system that simultaneously develops the center and the edge. Based on the original matrix, add 1 ring to the minimum angle and 1 ring to the maximum angle in the coke matrix, and subtract 0.5 rings from the minimum angle in the ore matrix.

[0012] 5) Add manganese ore to the washing furnace when the manganese content in the molten iron is above 0.8% and the (MnO) content in the slag is around 1.5%;

[0013] During the furnace cleaning process, the temperature difference of the water in the entire furnace should be controlled at 7.0-8.5℃, the air volume should not be less than 90% of the normal air volume, and the maximum should not exceed 5% of the normal air volume. The number of blocked tuyeres should not exceed 10% of the total number of tuyeres in the blast furnace. If it exceeds this number, it should be cleared gradually and systematically during the furnace cleaning process.

[0014] 6) Once the air volume and air pressure are symmetrical, the material feeding is smooth, and the top temperature is relatively stable, gradually expand the ore batch, increase the load, and restore the material distribution system;

[0015] 7) When the ore batch recovers to 95% of the normal ore batch, the load recovers to 95% of the normal load, the pressure-volume relationship is symmetrical, the material feeding is smooth, the material batch recovers to the normal level, and there are no hanging materials, collapse materials, etc., it indicates that the hearth accumulation treatment is over and the furnace condition adjustment is normal.

[0016] The beneficial effects of this invention are as follows: The method of this invention combines manganese ore washing, large air volume, small ore batches, full coke, centralized addition of circulating clean coke, and material distribution adjustment. It clarifies the ore batches and loads during the washing process, adjusts the material distribution, and controls the molten iron [Si], [Mn], slag (MnO), physical heat, binary basicity, water temperature difference, air volume usage, number of air outlets, and the amount and method of adding manganese ore at different stages. Generally, it only takes 3 to 10 days to eliminate hearth buildup and restore the furnace condition to normal. Attached Figure Description

[0017] Figure 1 This is a graph showing the temperature difference change of water during the treatment of furnace hearth accumulation in Example 1;

[0018] Figure 2This is a graph showing the change in (MnO) content in the slag accumulated in the hearth of Example 1.

[0019] Figure 3 This is a graph showing the change in Mn content in the molten iron deposited in the hearth during Example 1. Detailed Implementation

[0020] The present invention will be further described below with reference to embodiments, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0021] This invention provides a method for rapidly and effectively treating blast furnace hearth buildup, characterized by the following steps:

[0022] 1) Reduce the ore batch size to 85% of the original ore batch size used during blast furnace operation, based on the original ore usage ratio. For example, if the original ore batch size is 55 tons, the sinter usage is 70% (38.5t), the pellet usage is 25% (13.75t), and the lump ore usage is 5% (2.75t). If the ore batch size is 38 tons when the blast furnace is started, then the ore batch size will be changed to 32.3t, with the sinter usage being 70% (22.60t), the pellet usage being 25% (8.08t), and the lump ore usage being 5% (1.62t). Reduce the total coke load to 2.88 times, that is, based on the fuel ratio during normal blast furnace production, replace the coal ratio with a 1:1 coke ratio, and replace all the heat provided by pulverized coal injection in the blast furnace with coke. For example, if the original ore weight / coke weight = 4.66 times, it will now be changed to ore weight / coke weight = 2.88 times.

[0023] 2) After reducing the full coke load, centralized circulating coke addition is adopted. The coke addition method is to add coke every nine or ten batches (the first batch of centralized coke addition, followed by nine batches of normal material, and the tenth batch of centralized coke addition). The main purpose is to improve air permeability and create conditions for increased air volume. The centralized circulating coke addition is gradually cancelled after the air volume reaches the target value and stabilizes, the smooth operation of the blast furnace is significantly improved, and the furnace temperature reaches the target temperature.

[0024] 3) The content of molten iron [Si] is controlled at 1.0±0.2% and the physical heat is controlled at 1500±20℃ by adjusting the humidification amount and air temperature. The binary basicity is controlled at 1.09±0.01 times by adjusting the ore ratio.

[0025] 4) Upper adjustment: adopt a material distribution system that develops both the center and the edge simultaneously. Based on the original matrix, add 1 ring to the smallest angle (center plus coke) and add 1 ring to the largest angle (edge) in the coke matrix. Reduce 0.5 rings to the smallest angle (close to the center) in the ore matrix.

[0026] 5) Manganese ore washing furnace: Control target: The manganese content in the molten iron should be above 0.8%, and the MnO content in the slag should be controlled at around 1.5%.

[0027] Determining the amount of manganese ore added: The amount of manganese ore added is calculated based on the material balance, the current reduction rate of Mn element in the blast furnace (0.6-0.7), and the control target.

[0028] Actual addition amount of manganese ore at different stages: Since there is always residual slag and iron in the hearth, in order to quickly increase the [Mn] content in the molten iron and the (MnO content) in the slag, and accelerate the furnace cleaning effect, the amount of manganese ore added to each batch of the first n batches is 3 times the calculated amount of manganese ore added, and subsequent batches are added normally according to the calculated amount.

[0029] The formula for calculating n in the first n batches of manganese ore added is: n = 0.6 * blast furnace safe iron capacity / theoretical iron capacity per batch.

[0030] In formula (I):

[0031] The first 0.6—coke filling coefficient;

[0032] The second 0.6—safety factor;

[0033] D — furnace hearth diameter, m;

[0034] h—distance from the center line of the taphole to the center line of the slag taphole; for tapholes without slag taps, subtract 0.5m from the distance from the center line of the taphole to the center line of the tuyeres.

[0035] r 铁 — Density of molten iron, t / m³ 3 ;

[0036] 0.985 — Metal recovery rate, which can be determined based on the actual metal recovery rate of the blast furnace;

[0037] 0.945 — Iron content in molten iron, which can be determined based on the actual iron content in the molten iron from the blast furnace.

[0038] Adding manganese ore: Add it along with the ore, and place the manganese ore at the edge of the material surface platform and near the center. Specifically, calculate the angle of placement based on the material distribution matrix and ore batch, and alternate every 10 batches, while simultaneously handling the central accumulation and edge accumulation. As a preferred method, the central accumulation should be placed near the center, and the edge accumulation should be placed at the edge of the material surface platform. It is strictly forbidden to place it at the very edge of the material surface that directly contacts the furnace wall.

[0039] Adjustment of manganese ore addition: After 1.5 smelting cycles in the blast furnace, adjust the amount of manganese ore added in a timely manner according to the actual tapping results to achieve the control target.

[0040] 6) Mid-section adjustment: During furnace cleaning, adjust the water flow rate and inlet water temperature in a timely manner to control the overall furnace water temperature difference between 7.0 and 8.5℃. As the furnace cleaning progresses, the water temperature difference will rise rapidly. Increase the water flow rate in a timely manner until the water temperature difference is ≤8.5℃. To control the water temperature difference, the water flow rate can be increased to the maximum flow rate, and the inlet water temperature difference can be adjusted to 95% of the normal controlled inlet water temperature. However, when the water temperature difference is controlled and gradually decreases, adjust the water flow rate and inlet water temperature in a timely manner. The goal is for the water temperature difference to be no less than 7.0℃. Controlling the upper limit of the water temperature difference is to protect the cooling wall, and controlling the lower limit of the temperature difference is to improve the furnace cleaning effect.

[0041] 7) Lower-level adjustment

[0042] Airflow control: During the treatment of furnace hearth buildup, it is essential to maintain a sufficient airflow. Emphasis should be placed on maximizing airflow to ensure adequate blast energy. The airflow should not be less than 90% of the normal airflow, and should not exceed 5% of the normal airflow. For blocked air vents, the corresponding actual wind speed should be used as a reference to maintain a certain blast energy. For example, a 2500m³... 3 The normal blast furnace air volume is 4600 m³ / h. 3 / min, during the treatment of furnace hearth buildup, gradually strive to achieve an air volume of not less than 4140m³ / min. 3 / min, maintaining a certain wind speed and kinetic energy to accelerate the slag and iron circulation within the hearth and speed up the cleaning of the accumulated materials in the hearth, but not exceeding 4830m 3 / min, to prevent over-blowing and abnormal gas loss;

[0043] Tubular opening number adjustment: During furnace cleaning, the number of blocked tubular openings should not exceed 10% of the total number of tubular openings in the blast furnace. If it exceeds this, it should be cleared gradually and systematically during furnace cleaning. After clearing, the air volume should follow the air volume control principle. Adjust the air volume according to the number of air supply tubular openings used to ensure uniform air supply around the hearth, blowing through the center, accelerating slag and iron circulation, and ensuring the furnace cleaning effect. Preferably, the number of air supply tubular openings during furnace cleaning should be equal to the number of air supply tubular openings under normal furnace conditions.

[0044] Mining load adjustment: Continue to use large air volume to wash the furnace with manganese ore to improve the working condition of the hearth. After the relationship between air volume and air pressure is symmetrical, the material feeding is smooth, and the top temperature is relatively stable, adjust the load last in conjunction with the mining batch and material distribution system.

[0045] 8) When the ore batch recovers to 95% of the normal ore batch, the load recovers to 95% of the normal load, the pressure-volume relationship is symmetrical, the material feeding is smooth, the material batch recovers to the normal level, and there are no hanging materials, collapse materials, etc., it indicates that the hearth accumulation treatment is over and the furnace condition adjustment is normal.

[0046] Example 1

[0047] A certain 2500m 3 The blast furnace has a normal ore batch of 53t, an ore-coke load of 4.58 times, a daily output of approximately 7000t, a fuel ratio of 515kg / t, and a charging matrix. (Where C represents coke, O represents ore, and the superscript indicates the feeding angle of the feeding chute, such as the first column of the charging system.) This indicates that when the fabric chute is at a fabric feeding angle of 44.5°, the corresponding number of rotations required for the coke to be fed into the chute is 2. Similarly... This indicates that when the feeding chute is at a feeding angle of 42°, the corresponding number of rotations during ore feeding is 2. The water temperature difference is controlled at 5.5±0.5℃, and the normal air volume is 4600±30m³. 3 / min, 30 tuyeres, 27 air supply tuyeres. Due to deteriorating raw material quality and leaks in the tuyere sleeves, adhesions appeared in the upper and middle parts of the furnace body. After shutting down production, replacing the leaking sleeves, and making a series of adjustments, the adhesions in the furnace body began to fall off in large quantities, making the furnace condition difficult to manage. The hearth gradually deteriorated, with alkaline deposits accumulating. To prevent the furnace from cooling down, continuous concentrated addition of clean coke and prolonged high furnace temperatures led to graphite carbon accumulation in the hearth. The furnace condition showed accumulation in both the center and the edges. Daily output decreased to 3000t, the fuel ratio increased to 687kg / t, and the tuyere volume could not be maintained, so it could only be slowed down to 3500m. 3 Approximately / min.

[0048] This embodiment addresses the issue of furnace hearth buildup by following the method described below:

[0049] 1. Based on the original proportion of usable ore, reduce the ore batch to 32t and reduce the total coking load to 2.88 times.

[0050] 2. After removing the full coke load, add clean coke in a concentrated cycle. The coke adding method is to add two batches of clean coke (23t) in the first batch, then add two batches of clean coke (23t) in the tenth batch after a nine-batch interval, and repeat the cycle.

[0051] 3. The [Si] content of molten iron is controlled at 1.0%, the physical heat is controlled at 1500℃, and the binary basicity is controlled at 1.10 times.

[0052] 4. Upper adjustment: Adopting a fabric system that simultaneously develops the center and edges, the variation is as follows: Add 1 ring to the coke center (16.5°), add 1 ring to the edge of the largest angle (44.5°), subtract 0.5 rings at 31.5° (near the center) in the ore matrix, and increase all angles by 0.5° except for the center (16.5°).

[0053] 5. Manganese ore was used for furnace washing to control the manganese content in the molten iron to above 0.8% and the MnO content in the slag to around 1.5%. The added manganese ore had an MnO content of 31.39%, and the furnace charge structure was: 66.3% sinter + 28.7% pellets + 5% lump ore, with corresponding MnO contents of 0.19%, 0.20%, and 0.05%, respectively. The coke ash content was 13.08%, with MnO in the ash content of 0.44%. Based on the material balance and control targets, the required amount of manganese ore to be added per batch was calculated to be 0.8t / batch. To quickly increase the Mn content in the molten iron and the MnO content in the slag to achieve the furnace washing effect, the first 46 batches were added at a rate of 2.4t / batch.

[0054] The manganese ore is added as follows: manganese ore is placed at the edge of the material surface platform and near the center. The manganese ore enters the blast furnace together with the ore. The order of the first 10 batches of feeding is sinter → manganese ore → pellets → lump ore → sinter → coke. The manganese ore is placed at 39.5° (7th grade) near the edge of the material surface platform. The order of the next 10 batches of feeding is sinter → pellets → lump ore → sinter → manganese ore → coke. The manganese ore is placed at 32° (5th grade) near the center of the material surface. The order is changed every 10 batches, and the accumulation at the center and the edge is treated at the same time.

[0055] After 1.5 smelting cycles (71 batches) in the blast furnace, based on the (MnO) content in the slag being 1.02%, the amount of manganese ore added was adjusted to 1.2t / batch.

[0056] 6. During boiler cleaning, the water temperature difference increases significantly, and the soft water flow rate decreases from the normal 4500 m³ / h. 3 / h, gradually increase to 4900m 3 / h, and adjust the water temperature difference from 41℃ to 38℃, with the goal of controlling the overall boiler water temperature difference to 8.0℃.

[0057] 7. During the furnace cleaning process, the air volume is gradually increased to 4660m³ / h. 3 / min, up to 4780m 3 / min, and maintained at 4700m for a long time. 3 / min or higher. During this period, depending on the air volume maintenance, pressure-volume relationship, and furnace temperature after the air is added, the centralized addition of circulating clean coke will be gradually reduced, from adding 10 times every nine days (clean coke 23t) to adding 10 times every nine days (clean coke 11.5t) and then to adding 10 times every nine days (clean coke 5t), until it is cancelled.

[0058] 8. Before cleaning the blast furnace, in order to ensure smooth operation of the blast furnace, 7 tuyeres are blocked. During the cleaning process, depending on the furnace condition, air volume, furnace temperature and pressure, 4 tuyeres are gradually and quickly opened, and air is supplied through 27 tuyeres. 3 are then blocked, which is the same number of air supplied as under normal furnace conditions.

[0059] 9. During step 6, depending on the hourly material feeding, air volume, pressure relationship, and top temperature fluctuations, and whether there is any hanging or slipping material, gradually increase the ore batch size from 32t to 36t to 40t to 44t to 48t to 51t to 52t to 53t. After increasing the ore batch size to 36t, increase the load, adjusting it to: 2.88 to 3.51 to 3.86 to 4.21 to 4.32 to 4.37 to 4.45 to 4.50. After the furnace condition stabilizes and runs smoothly, increase the load to 4.58 depending on the furnace condition. Simultaneously, gradually return the material distribution matrix to normal, and gradually return the water temperature difference control to normal levels.

[0060] 10. When the ore batch and load return to 95% of the normal ore batch, the pressure-volume relationship is symmetrical, the material feeding is smooth, the material batch returns to the normal level, and the top temperature is relatively stable, the output and fuel ratio return to 95% of the normal level, it indicates that the hearth accumulation treatment is over and the furnace condition adjustment is normal.

[0061] The changes in water temperature difference, MnO content in slag, and Mn content in molten iron during furnace cleaning are as follows: Figure 1-3 As shown.

[0062] from Figure 1 It can be seen that when dealing with the buildup in the hearth, the water temperature difference increases rapidly as the furnace washing process proceeds. The temperature difference is gradually increased to 4900m. 3 / h, and measures to adjust the water temperature difference from 41℃ to 38℃, strictly control the water temperature difference of the whole furnace within 7~8.5℃. Controlling the upper limit temperature is to protect the cooling wall, and controlling the lower limit temperature is to improve the furnace washing effect.

[0063] from Figure 2 As can be seen, when dealing with hearth buildup, with the addition of manganese ore, the mass fraction of (MnO) in the slag rapidly increases from 0.13% under normal furnace conditions to 0.61%, reaching a maximum of 1.76%, and remains at around 1.45% for a relatively long period of time, maintaining a reasonable (MnO) content in the slag. At this time, the viscosity of the slag is low within the controlled temperature range, the fluidity is greatly improved, the melting temperature is more suitable, and the stability of the slag is strong, which can quickly and effectively achieve the furnace cleaning effect.

[0064] from Figure 3 As can be seen, when dealing with hearth buildup, the [Mn] content in molten iron increases rapidly from 0.18% under normal furnace conditions to 0.73% with the addition of manganese ore, reaching a maximum of 1.22%, and remaining above 1% for a considerable period. With the increase of [Mn], the viscosity of molten iron decreases and its fluidity is significantly improved. At the same time, manganese promotes the increase of [C]. With the increase of [Mn] and [C], the freezing point of molten iron further decreases, and the fluidity of molten iron further improves.

[0065] The effect of Example 1 on treating furnace hearth buildup is shown in Table 1:

[0066] Table 1. Iron production and fuel ratio for treating hearth buildup in Example 1.

[0067] time Iron production (t) Fuel ratio (kg / t) Before cleaning the stove 3000 687 Stove cleaning day 1 3047 677 Stove cleaning day 2 4665 630 Day 3 of cleaning the furnace 6149 533 4th day of cleaning the furnace 6832 523 5th day of furnace cleaning 7021 516

[0068] As shown in Table 1, the method of this invention significantly shortens the treatment cycle for hearth buildup. Furnace conditions improve markedly after 3 days, and production and fuel ratio return to normal levels after 5 days. Before furnace cleaning, daily production decreased to 3000t, and the fuel ratio increased to 687kg / t. After 3 days, furnace operation improved significantly, with production reaching 6149t and the fuel ratio decreasing to 533kg / t. After 5 days, production reached 7021t, and the fuel ratio was 516kg / t, with both production and fuel ratio fully recovered. This method achieves rapid, safe, and efficient treatment of hearth buildup. Based on the cost of restoring furnace conditions in 10 days, this invention can reduce costs by over 10 million yuan.

[0069] Comparative Example 1

[0070] A certain 2000m 3 The blast furnace experienced hearth wall adhesion. During the treatment process, measures such as low blast volume, low smelting strength, the use of edge-feed systems, and repeated concentrated coke additions and hot washing further deteriorated the hearth's operating condition, ultimately leading to severe deterioration and significant accumulation of deposits. During this 103-day furnace condition recovery process, three stages of manganese ore treatment were employed to address the hearth deposits, but the overall results were unsatisfactory.

[0071] In the initial stage of furnace malfunction, during the process of dealing with furnace wall adhesion, the hearth malfunctioned due to high [Si] content, slow airflow, and repeated coke additions, resulting in hearth buildup. To improve the hearth's condition, manganese ore was added for washing, but due to the lack of a reasonable technical guideline for using manganese ore for washing and the failure to promptly reduce ore volume and load, the airflow decreased from the normal 3600 m³ / min to 2600 m³ / min. 3 / min, which causes [Si] to be around 1.0%, the molten iron becomes viscous, and the purpose of cleaning the hearth is not achieved, so the use of manganese ore is stopped;

[0072] Subsequently, the furnace hearth deteriorated further, with increased buildup and a reduction in airflow to 1800 m³. 3 The furnace hearth had extremely poor permeability, and soon five tuyeres suffered consecutive damage, eventually leading to blasting and burning out seven intermediate tuyeres. An emergency shutdown was implemented to address the water leakage in the intermediate and minor tuyeres. Air supply was then reduced by blocking 22 tuyeres (out of a total of 28). A method of reducing ore batches and then reverting to a full coke batch with manganese ore for furnace washing was adopted, instead of centralized coke circulation. The air volume was increased to 3000 m³ / min. 3 / min, the blast furnace does not accept air volume, the pressure-volume relationship is tense, and the collapse and slippage of materials are frequent. Since it is a whole coke smelting, only the coke group during the collapse is added, and the centralized addition of circulating coke is not adopted. There are also no reasonable technical points for using manganese ore to wash the furnace. Later, during the furnace washing process, the physical heat of the molten iron dropped to 1280℃, causing the blast furnace condition to cool down.

[0073] Initially, the cooling of the furnace was addressed by adding large amounts of clean coke and fluorite. After the cooling was effectively stopped, the buildup in the hearth intensified, forming an accumulation of graphite carbon at the edges, center, and then on. Manganese ore was then added to wash the furnace, reducing the ore batch to 85% of the initial batch size. Circulating coke was added in concentrated batches every nine to ten days. The [Si] content in the molten iron was controlled at 1.0 ± 0.2%, the physical heat was controlled at ≥1480℃, the binary basicity was controlled at 1.0 times, and the manganese content in the molten iron was controlled at 0.8%. The goal was to increase the blast volume to 3200 m³ / h. 3 The airflow was above 3300 m³ / min, and measures were taken to narrow the ore platform, move the ore corner outward, and divert the material distribution in the center; however, the upper adjustment did not adopt a material distribution system that simultaneously developed the center and the edge, resulting in unstable airflow and air volume reaching 3300 m³ / min. 3 The flow rate could not be stabilized above a certain value; adjustments were made in the middle section to adjust the water flow rate and inlet water temperature in a timely manner, controlling the temperature difference of the entire furnace water below 7.5℃, but the lower limit temperature was not controlled; and the technical points for using manganese ore to wash the furnace only specified that the manganese content in the molten iron should be around 0.8%, without emphasizing the control of the (MnO) content in the slag. In reality, the manganese content in the molten iron was around 0.8%, and the (MnO) content in the slag was around 1.0%. The above factors resulted in poor furnace washing effect. The use of manganese ore was only stopped after 15 days of continuous furnace washing, and the furnace condition improved significantly and gradually recovered, resulting in the entire furnace condition recovery process taking as long as 103 days.

[0074] Conventional methods for treating furnace hearth buildup all have the problem of being too time-consuming. Comparative Example 1 is only one of the conventional methods for treating furnace hearth buildup. The comparison shows that the method of the present invention greatly improves the effect of treating furnace hearth buildup (furnace hearth buildup can be effectively treated in 5-10 days).

Claims

1. A method for rapidly and effectively treating blast furnace hearth buildup, characterized in that, Follow these steps to achieve the following: 1) Reduce the ore batch size to 85% of the batch size for furnace operation, and reduce the total coke load to 2.88 times; 2) After the full coke load is removed, the method of adding coke every nine or ten batches is adopted to centrally add clean coke in a cyclical manner. The method of adding coke every nine or ten batches means that the first batch of clean coke is added centrally, and after nine batches of normal material in between, the tenth batch of clean coke is added centrally again, and the cycle is repeated. 3) By adjusting the humidification and air temperature, the Si content of molten iron is controlled at 1.0±0.2%, and the physical heat is controlled at 1500±20℃. By adjusting the ore ratio, the binary basicity is controlled at 1.09±0.01 times. 4) Adopt a material distribution system that simultaneously develops the center and the edge. Based on the original matrix, add 1 ring to the minimum angle and 1 ring to the maximum angle in the coke matrix, and subtract 0.5 rings from the minimum angle in the ore matrix. 5) Add manganese ore to the washing furnace when the manganese content in the molten iron is above 0.8% and the MnO content in the slag is 1.5%; During the furnace cleaning process, the temperature difference of the water in the entire furnace should be controlled at 7.0~8.5℃, the air volume should not be less than 90% of the normal air volume, and the maximum should not exceed 5% of the normal air volume. The number of blocked tuyeres should not exceed 10% of the total number of tuyeres in the blast furnace. If it exceeds this number, it should be cleared gradually and systematically during the furnace cleaning process. 6) Once the air volume and air pressure are symmetrical, the material feeding is smooth, and the top temperature is relatively stable, gradually expand the ore batch, increase the load, and restore the material distribution system; 7) When the ore batch recovers to 95% of the normal ore batch, the load recovers to 95% of the normal load, the pressure-volume relationship is symmetrical, the material feeding is smooth, the material batch recovers to the normal level, and there is no hanging or collapsing of material, it indicates that the hearth accumulation treatment is over and the furnace condition adjustment is normal.

2. The method for rapidly and effectively treating blast furnace hearth buildup according to claim 1, characterized in that, In step 5), the amount of manganese ore added is determined based on the material balance, the current reduction rate of Mn element in the blast furnace, and the control target, and the amount of manganese ore added for each batch of material is calculated in reverse. Actual amount of manganese ore added at different stages: For the first n batches of material, the amount of manganese ore added to each batch is 3 times the calculated amount of manganese ore added, and subsequent batches are added normally according to the calculated amount; Where n = 0.6 × safe iron capacity of blast furnace / theoretical iron capacity of batch, the calculation formula is: （I）； In formula (I): The first 0.6—coke filling coefficient; The second 0.6—safety factor; D — Furnace hearth diameter, in meters; h —Distance from the center line of the taphole to the center line of the slag outlet; for tapholes without slag outlets, subtract 0.5m from the distance from the center line of the taphole to the center line of the tuyeres. r 铁 — Density of molten iron, t / m³ 3 ; 0.985 — Metal yield; 0.945 — Iron content in molten iron.

3. The method for rapidly and effectively treating blast furnace hearth buildup according to claim 1, characterized in that, In step 5), the manganese ore is added along with the ore. The manganese ore is placed at the edge of the material surface platform and near the center. Specifically, the angle of the material is calculated according to the material distribution matrix and the batch of ore. The material is changed every 10 batches, and the center accumulation and edge accumulation are processed at the same time.

4. The method for rapidly and effectively treating blast furnace hearth buildup according to claim 3, characterized in that, In step 5), the amount of manganese ore added is adjusted according to the MnO content in the slag after 1.5 smelting cycles in the blast furnace.

5. The method for rapidly and effectively treating blast furnace hearth buildup according to claim 1, characterized in that, In step 5), the number of air outlets during the furnace cleaning period is equal to the number of air outlets under normal furnace conditions.

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