Explosion venting prevention smelting method for converter digestion dedusting ash balls

Abstract

The invention provides a converter digestion dedusting ash ball explosion venting prevention smelting method. The method sequentially comprises the steps that blast furnace molten iron enters a desulfurization station to be subjected to desulfurization and slagging-off operation; a top-bottom combined blowing converter is used for smelting; and blowing adopts a low-high-low oxygen supply operation mode. On the premise that a dry dedusting system is used in the converter process, dedusting ash balls are digested in the converter blowing process, recycling of solid waste is achieved, the explosion venting frequency is effectively controlled to be 0-1 time / month, the cost of the steelmaking process is reduced, pollution to the environment is reduced, the production operation process is simple, and the matching degree with an existing commonly-used electric dedusting process is high.

Description

Technical Field

[0001] The invention relates to the technical field of converter smelting, and in particular to a converter digestion and dust removal ash ball explosion prevention smelting method. Background Art

[0002] Modern steel mills keep up with national environmental protection requirements, and most of them use dry dust removal systems. Although this system effectively controls the dust content in the flue gas and meets national environmental protection standards; however, as time accumulates, the dust removal system produces more and more iron-containing oxides, which become a kind of iron-containing solid waste. Directly selling it out not only wastes iron-containing resources, but may also cause pollution to the environment. Therefore, studying how to deal with this iron-containing solid waste has become a research direction for many steel companies.

[0003] The resulting iron oxides are processed outsourced into dust-collecting balls and recycled as coolant in the converter smelting process, replacing existing coolants such as sintered ore. However, the carbon content in the dust-collecting balls often leads to explosions when added during the blowing process, disrupting the normal smelting process and equipment stability. Therefore, preventing explosions during converter digestion of dust-collecting balls is a particularly important and challenging issue. Summary of the Invention

[0004] The present invention proposes a method for preventing explosion of ash balls during converter digestion and dust removal, aiming to solve the problem of frequent explosion of ash balls during converter smelting in existing steel plants.

[0005] In order to achieve the above-mentioned object, the present invention adopts the following technical solution: a converter digestion dust removal ash ball explosion prevention smelting method, the method comprises the following steps in sequence:

[0006] S1, blast furnace molten iron enters the desulfurization station for desulfurization and slag removal operations;

[0007] S2, using top and bottom blown converter for smelting;

[0008] S3, blowing adopts low-high-low oxygen supply operation mode;

[0009] S3.1. After ignition is normal, when blowing reaches 2% of the oxygen supply process, the ignition gun is raised to the normal blowing gun position, and the ignition oxygen supply is 15000Nm 3 / h, after the first time, the oxygen supply will be automatically increased step by step to 30000-32000Nm 3 / h, add the first batch of slag material after the flame is blown normally. The slag material includes dust removal ash balls and other calcium auxiliary materials. The addition amount is 1 / 3-1 / 2 of the total addition amount. After the first batch of slag material is added, continue to add slag material. If the flame is abnormal, stop adding in time. Wait until the flame is normal and then add it in time. The principle of adding materials is multiple batches and small batches. The addition amount of other calcium auxiliary materials in each batch is 300-500kg. Lime is added according to the alkalinity requirements 10 minutes before smelting. Dust removal ash balls or sintered ore are added according to the requirements of molten steel temperature 12 minutes before smelting;

[0010] S3.2. When the carbon-oxygen reaction begins, add the second batch of slag-making material. Add in small batches or multiple batches according to the slagging situation. During the smelting process, adjust the gun position and the timing of adding materials according to the slagging effect of the dust-collecting ash balls. The amount of dust-collecting ash balls added to the slag-making material per batch should be ≤500kg, and the amount of other calcium auxiliary materials added per batch should be ≤500kg.

[0011] S3.3. When blowing reaches 85-90% of the oxygen supply process, use the auxiliary gun TSC probe to determine carbon, measure temperature and take samples. Then, according to the carbon determination and measured temperature, add some slag material for adjustment. Smelting is tracked according to the auxiliary gun test results until the smelting process requirements are met and the gun is started. At the end of blowing, use the auxiliary gun TSO probe to determine carbon, measure temperature, take samples and determine oxygen. Before starting the gun at the end, the deep blowing gun position is lowered to 900mm and the oxygen supply is increased to 32000Nm 3 / h, to carry out deep decarburization and uniform steel liquid composition and temperature.

[0012] Preferably, the parameters of the desulfurization operation in step 1 are controlled as follows: inlet temperature ≥ 1350°C, desulfurizer dosage 4-6 kg / t, speed during feeding 60-70 rpm, speed after feeding 80-100 rpm, and stirring time controlled at 15-20 min.

[0013] Preferably, the raw material composition and weight percentage of the metal main material input into the smelting process in step 2 are: 80-85% molten iron, the balance is scrap steel, the Si content in the molten iron is 0.20-0.55%, the Mn content is 0.25-0.45%, and the slag content is ≤0.5%.

[0014] Preferably, in step 3.1, the blowing intensity is controlled to be 3.5-4.5 Nm 3 / min·t, the bottom blowing argon flow rate is controlled at 0.05-0.10Nm 3 / min·t, the ignition gun position for blowing is set at 1500mm, and the normal blowing gun position is 1400-1800mm. The slag-making material is added using a symmetrical silo, and the dust-collecting balls are added using a continuous feeding silo to ensure smooth addition of the dust-collecting balls and reduce the carbon-oxygen reaction caused by the dust-collecting balls.

[0015] Preferably, the components and proportions of the dust removal balls in step 3.2 are: TFe ≥ 50%, CaO ≥ 7%, SiO2 ≤ 5%, P ≤ 0.20%, S ≤ 0.20%, H2O ≤ 5%, surface strength ≥ 800N / piece, and the particle size range of the dust removal balls is 10-50mm, which is greater than 90%.

[0016] Preferably, the dust removal balls in step 3 melt relatively slowly. To prevent them from being insufficiently melted and reduced, the dust removal balls should not be added 3 minutes before the end of smelting.

[0017] Preferably, the dust removal balls described in step 3 have a certain carbon content. Adding more during re-blowing will cause the CO concentration in the flue gas to rise sharply, bringing the risk of explosion. Therefore, the amount of dust removal balls added during re-blowing should be controlled to ≤1000kg, and the excess can be replaced with lime or limestone; if the adjustment range is large and more than 1000kg of dust removal balls need to be added, a nitrogen curtain operation must be performed.

[0018] Preferably, the weight percentages of the components of the desulfurizer in step 1 are: CaO ≥ 80.0%, SiO2 ≤ 5.0%, CaF2 ≥ 7.0%, S ≤ 0.040%, and the particle size of the desulfurizer is 0.2-1.5 mm.

[0019] Compared with the prior art, the advantages and positive effects of the present invention are:

[0020] On the premise of using a dry dust removal system in the converter process, the converter blowing process digests the dust balls, realizes the recycling and reuse of solid waste, and effectively controls the explosion frequency to 0-1 times / month. It not only reduces the cost of the steelmaking process, but also reduces pollution to the environment. The production operation process is simple and highly compatible with the currently commonly used electrostatic precipitator process. DETAILED DESCRIPTION

[0021] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below through embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] The converter flue gas contains a large amount of iron oxides. After passing through the dry dust removal system, coarse ash and fine ash will be generated in sequence, plus iron oxide scale produced by billeting or finishing, which together constitute the raw materials for solid waste recycling in steel plants. The carbon and total iron content of the three iron-containing solid wastes vary greatly. The ratio is designed based on the monthly production of converter dust ash and iron oxide scale and the requirements of the steelmaking process: dust ash 30-60%, iron oxide scale 20-50%, binder 3-6%. Through high-efficiency composite adhesives and corresponding process technologies, the iron oxides are mixed according to the ratio and then pressed into dust ash balls. Its components are TFe≥50%, CaO≥7%, SiO2≤5%, P≤0.20%, S≤0.20%, H2O≤5%, surface strength ≥800N / piece, and the particle size range of dust ash balls is 10-50mm, which is greater than 90%.

[0024] Electrostatic precipitator (ESP) explosion venting occurs during the converter steelmaking process, where molten iron reacts violently with oxygen, generating large quantities of high-temperature flue gas. Although the furnace mouth utilizes a slightly positive pressure design, some air inevitably enters the atmosphere. The main components of this flue gas include CO, CO₂, O₂, N₂, and dust. CO is the primary flammable gas in this flue gas. The conditions for an explosion are: ① The combustible gas-oxygen mixture must reach its explosion limit (ω(CO)) ≥ 9%, ω(O₂) ≥ 6%; or ω(H₂) ≥ 3%, ω(O₂) ≥ 4%; ② The presence of an open flame, i.e., sparks generated by discharge between the plates; and ③ The ESP is located in a confined space, such as the ESP. During ESP operation, sparks are inevitable. Therefore, if the gas mixture exceeds the specified limit, an explosion can occur within the ESP, causing the explosion vent valve to open.

[0025] Example 1

[0026] This embodiment provides a method for preventing explosion of ash balls during converter digestion and dust removal, which can solve the problem of frequent explosion of ash balls during converter smelting in existing steel plants.

[0027] The smelting method comprises the following steps in sequence:

[0028] S1. The blast furnace molten iron enters the desulfurization station for desulfurization and slag removal. Specifically, the station temperature is 1350°C, the desulfurizer dosage is 4kg / t, the speed is 60rpm during charging, the speed is 80rpm after charging, the stirring time is controlled to 15min, and the molten iron after desulfurization is subjected to slag removal.

[0029] S2. Use a top-bottom combined-blown converter for smelting, with the following weight percentages of the raw materials used for the main metal feed: 80% molten iron, the balance being scrap steel, with a Si content of 0.20% and a Mn content of 0.25% in the molten iron, a temperature of 1350° C. at the desulfurization station, and a slag content of 0.5%;

[0030] S3, blowing adopts low-high-low oxygen supply operation mode, and the oxygen supply intensity is controlled at 3.5Nm 3 / (min·t), the bottom blowing argon flow rate is controlled at 0.05Nm 3 / (min·t), the ignition gun position is set to 1500mm, after ignition is normal, when the blowing reaches 2% of the oxygen supply process, the ignition gun is raised to the normal blowing gun position of 1600mm, and the ignition flow rate is 15000Nm 3 / h, and automatically increases the oxygen supply in steps to 30000 Nm after 45 seconds 3 / h, add the first batch of slag material (including dust removal balls and other calcium auxiliary materials) 1 minute after the start of blowing, the addition amount is 1 / 3 of the total addition amount, and use symmetrical silos to add, among which the dust removal balls are mainly added in continuous feeding silos, so that the dust removal balls can be added smoothly and the carbon-oxygen reaction caused by the dust removal balls can be weakened; after the first batch of slag material is added, continue to add slag material, if the flame is abnormal, stop adding in time, and add in time after the flame returns to normal, the feeding principle is multiple batches and small batches, and the addition amount of other calcium auxiliary materials for each batch is 300kg. Before smelting for 10 minutes, add enough lime according to the alkalinity requirements, and before smelting for 12 minutes, add enough dust removal balls or sintered ore according to the requirements and the molten steel temperature;

[0031] S4. When the carbon-oxygen reaction starts, add the second batch of slag-making materials. According to the slagging situation, follow the principle of adding multiple batches and small batches. The amount of dust-removing ash balls added is 450 kg per batch. The amount of other slagging materials added is 450 kg per batch. The iron content and cooling effect of dust-removing balls are similar to those of blast furnace return ore, but the slagging effect is relatively slow. The gun position and feeding time should be adjusted according to the actual use effect during the smelting process. The dust-removing ash balls melt relatively slowly. In order to prevent them from not being fully melted and reduced, dust-removing ash balls should not be added 3 minutes before the end of smelting.

[0032] S5. When blowing reaches 85-90% of the oxygen supply process, use the auxiliary gun TSC probe to determine carbon, measure temperature and take samples. Then, according to the carbon determination and measured temperature, add some slag material for adjustment. Smelting is tracked according to the auxiliary gun test results until the smelting process requirements are met and the gun is started. At the end of blowing, use the auxiliary gun TSO probe to determine carbon, measure temperature, take samples and determine oxygen. Before starting the gun at the end, the deep blowing gun position is lowered to 900mm and the oxygen supply is increased to 32000Nm 3 / h, to carry out deep decarburization and uniform molten steel composition and temperature;

[0033] S6. The dust removal ash balls have a certain carbon content. Adding too much during re-blowing will cause the CO concentration in the flue gas to rise sharply, bringing the risk of explosion. Therefore, the ball quantity added during re-blowing should be controlled to ≤1000kg, and the excess can be replaced with lime or limestone. If the adjustment range is large and more than 1000kg of dust removal ash balls need to be added, nitrogen curtain operation must be performed.

[0034] The components and proportions of the dust removal ash balls in this embodiment are: TFe 80%, CaO 9.6%, SiO25%, P0.20%, S 0.20%, H2O 5%, the surface strength is 800N / piece, and the particle size range of the dust removal ash balls is 10-50mm, accounting for 90%.

[0035] The weight percentages of the components of the desulfurizer of this embodiment are: CaO 80.0%, SiO2 5.0%, CaF1 4.96%, S 0.040%, and the particle size of the desulfurizer is 0.5-1.0 mm.

[0036] Example 2

[0037] The smelting method comprises the following steps in sequence:

[0038] S1. The blast furnace molten iron enters the desulfurization station for desulfurization and slag removal. Specifically, the station temperature is 1380°C, the desulfurizer dosage is 4kg / t, the speed is 65rpm during charging, the speed is 90rpm after charging, the stirring time is controlled to 18min, and the molten iron after desulfurization is subjected to slag removal.

[0039] S2. Use a top-bottom combined-blown converter for smelting, with the following weight percentages of the raw materials used for the main metal feed: 83% molten iron, the balance being scrap steel, with a Si content of 0.35% and a Mn content of 0.35% in the molten iron, a temperature of 1400°C at the desulfurization station, and a slag content of 0.4%;

[0040] S3, blowing adopts low-high-low oxygen supply operation mode, and the oxygen supply intensity is controlled at 4Nm 3 / (min·t), the bottom blowing argon flow rate is controlled at 0.08Nm 3 / (min·t), the blowing ignition gun position is set to 1500mm, after the ignition is normal, when the blowing reaches 2% of the oxygen supply process, it is raised to the normal blowing gun position of 1700mm, and the ignition flow rate is 15000Nm 3 / h, and automatically increases the oxygen supply in steps to 31000 Nm after 45 seconds 3 / h, add the first batch of slag-making materials (including dust removal balls and other calcium auxiliary materials) 1 minute after the start of blowing, the addition amount is 45% of the total addition amount, and use symmetrical silos to add; the dust removal balls are mainly added in continuous silos to ensure smooth addition of dust removal balls and reduce the carbon-oxygen reaction caused by the dust removal balls;

[0041] S4. When the carbon-oxygen reaction starts, add the second batch of slag-making materials. According to the slagging situation, follow the principle of adding multiple batches and small batches; the amount of dust-removing ash balls added is 450 kg per batch; the amount of other slag-making materials added is 450 kg per batch; the iron content and cooling effect of dust-removing balls are similar to those of blast furnace return ore, but the slagging effect is relatively slow. During the smelting process, adjust the gun position and the timing of adding materials according to the actual use effect; dust-removing ash balls melt relatively slowly. In order to prevent them from not being fully melted and reduced, dust-removing ash balls should not be added 3 minutes before the end of smelting;

[0042] S5. When blowing reaches 88% of the oxygen supply process, use the auxiliary gun TSC probe to determine carbon, measure temperature and take samples. Then, according to the carbon determination and measured temperature, add some slag material for adjustment. According to the auxiliary gun test results, smelting is tracked until the smelting process requirements are met and the gun is started. At the end of blowing, use the auxiliary gun TSO probe to determine carbon, measure temperature, take samples and determine oxygen. Before starting the gun at the end, the deep blowing gun position is lowered to 900mm and the oxygen supply is increased to 32000Nm 3 / h, to carry out deep decarburization and uniform molten steel composition and temperature;

[0043] S6. The dust removal ash balls have a certain carbon content. Adding too much during re-blowing will cause the CO concentration in the flue gas to rise sharply, bringing the risk of explosion. Therefore, the ball quantity for re-blowing should be controlled at 900kg, and the excess can be replaced with lime or limestone. If the adjustment range is large and more than 1000kg of dust removal ash balls need to be added, nitrogen curtain operation must be performed.

[0044] The components and proportions of the dust removal balls in this embodiment are: TFe 82%, CaO 8%, SiO25%, P 0.18%, S 0.18%, H2O 4.64%, the surface strength is 800N / piece, and the particle size range of the dust removal balls is 10-50mm, accounting for 95%.

[0045] The weight percentages of the components of the desulfurizer of this embodiment are: CaO 85.0%, SiO2 4.0%, CaF1 0.97%, S 0.030%, and the particle size of the desulfurizer is 0.2-0.8 mm.

[0046] Example 3

[0047] The smelting method comprises the following steps in sequence:

[0048] S1. The blast furnace molten iron enters the desulfurization station for desulfurization and slag removal. Specifically, the station temperature is 1450°C, the desulfurizer dosage is 5kg / t, the speed is 70rpm during charging, the speed is 100rpm after charging, the stirring time is controlled to 20min, and the molten iron after desulfurization is subjected to slag removal.

[0049] S2. Use a top-bottom combined-blown converter for smelting, with the following weight percentages of the raw materials used for the main metal feed: 85% molten iron, the balance being scrap steel, with a Si content of 0.55% and a Mn content of 0.45% in the molten iron, a temperature of 1500°C at the desulfurization station, and a slag content of 0.45%;

[0050] S3, blowing adopts low-high-low oxygen supply operation mode, and the oxygen supply intensity is controlled at 4.5Nm 3 / (min·t), the bottom blowing argon flow rate is controlled at 0.10Nm 3 / (min·t), the blowing ignition gun position is set to 1500mm, after the ignition is normal, when the blowing reaches 2% of the oxygen supply process, it is raised to the normal blowing gun position of 1800mm, and the ignition flow rate is 15000Nm 3 / h, and automatically increases the oxygen supply in steps to 32000 Nm after 45 seconds 3 / h, add the first batch of slag-making materials (including dust removal balls and other calcium auxiliary materials) 1 minute after the start of blowing, the added amount is 1 / 2 of the total amount, and it is added using symmetrical silos; the dust removal balls are mainly added in continuous silos to ensure smooth addition of the dust removal balls and reduce the carbon-oxygen reaction caused by the dust removal balls;

[0051] S4. When the carbon-oxygen reaction starts, add the second batch of slag-making materials. According to the slagging situation, follow the principle of adding multiple batches and small batches; the amount of dust-removing ash balls added is 480 kg per batch; the amount of other slag-making materials added is 480 kg per batch; the iron content and cooling effect of dust-removing balls are similar to those of blast furnace return ore, but the slagging effect is relatively slow. During the smelting process, adjust the gun position and feeding time according to the actual use effect; dust-removing ash balls melt relatively slowly. In order to prevent them from not being fully melted and reduced, dust-removing ash balls should not be added 3 minutes before the end of smelting;

[0052] S5. When blowing reaches 90% of the oxygen supply process, use the auxiliary gun TSC probe to determine carbon, measure temperature and take samples. Then, according to the carbon determination and the measured temperature, add some slag material for adjustment. According to the auxiliary gun test results, smelting is tracked until the smelting process requirements are met and the gun is started. At the end of blowing, use the auxiliary gun TSO probe to determine carbon, measure temperature, take samples and determine oxygen. Before starting the gun at the end, the deep blowing gun position is lowered to 900mm and the oxygen supply is increased to 32000Nm 3 / h, to carry out deep decarburization and uniform molten steel composition and temperature;

[0053] S6. The dust removal ash balls have a certain carbon content. Adding too much during re-blowing will cause the CO concentration in the flue gas to rise sharply, bringing the risk of explosion. Therefore, the ball quantity added during re-blowing should be controlled to ≤1000kg, and the excess can be replaced with lime or limestone. If the adjustment range is large and more than 1000kg of dust removal ash balls need to be added, nitrogen curtain operation must be performed.

[0054] The components and proportions of the dust removal ash balls in this embodiment are: TFe 82%, CaO 8.12%, SiO2 4.5%, P 0.19%, S 0.19%, H2O 5%, the surface strength is 800N / piece, and the particle size range of the dust removal ash balls is 10-50mm, accounting for 90%.

[0055] The weight percentages of the components of the desulfurizer of this embodiment are: CaO 90.0%, SiO2 2.0%, CaF 7.97%, S 0.030%, and the particle size of the desulfurizer is 1.0-1.5 mm.

[0056] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A converter digestion and dust removal ash ball explosion prevention smelting method, characterized in that: The method comprises the following steps in sequence: S1, blast furnace molten iron enters the desulfurization station for desulfurization and slag removal operations; S2, using top and bottom blown converter for smelting; S3, blowing adopts low-high-low oxygen supply operation mode; S3.

1. After ignition is normal, when the blowing reaches 2% of the oxygen supply process, the ignition gun is raised to the normal blowing gun position, and the ignition oxygen supply is 15000Nm 3 / h, after the first time, the oxygen supply will be automatically increased step by step to 30000-32000Nm 3 / h, add the first batch of slag material after the flame is blown normally. The slag material includes dust removal ash balls and other calcium auxiliary materials. The addition amount is 1 / 3-1 / 2 of the total addition amount. After the first batch of slag material is added, continue to add slag material. If the flame is abnormal, stop adding in time. Wait until the flame is normal and then add it in time. The principle of adding materials is multiple batches and small batches. The addition amount of other calcium auxiliary materials in each batch is 300-500kg. Lime is added according to the alkalinity requirements 10 minutes before smelting. Dust removal ash balls or sintered ore are added according to the requirements of molten steel temperature 12 minutes before smelting; S3.

2. When the carbon-oxygen reaction begins, add the second batch of slag-making material. Add in small batches or multiple batches according to the slagging situation. During the smelting process, adjust the gun position and the timing of adding materials according to the slagging effect of the dust-collecting ash balls. The amount of dust-collecting ash balls added to the slag-making material per batch should be ≤500kg, and the amount of other calcium auxiliary materials added per batch should be ≤500kg. S3.

3. When blowing reaches 85-90% of the oxygen supply process, use the auxiliary gun TSC probe to determine carbon, measure temperature and take samples. Then, according to the carbon determination and measured temperature, add some slag material for adjustment. Smelting is tracked according to the auxiliary gun test results until the smelting process requirements are met and the gun is started. At the end of blowing, use the auxiliary gun TSO probe to determine carbon, measure temperature, take samples and determine oxygen. Before starting the gun at the end, the deep blowing gun position is lowered to 900mm and the oxygen supply is increased to 32000Nm 3 / h, to carry out deep decarburization and uniform steel liquid composition and temperature.

2. The converter digestion and dust removal ash ball explosion prevention smelting method according to claim 1 is characterized in that: The parameters of the desulfurization operation in step 1 are as follows: the inlet temperature is ≥1350°C, the desulfurizer dosage is 4-6kg / t, the speed is 60-70rpm during feeding, the speed is 80-100rpm after feeding, and the stirring time is controlled to 15-20min.

3. The converter digestion and dust removal ash ball explosion prevention smelting method according to claim 1 is characterized in that: The raw material composition and weight percentage of the metal main material input into the smelting process in step 2 are: 80-85% molten iron, the balance is scrap steel, the Si content in the molten iron is 0.20-0.55%, the Mn content is 0.25-0.45%, and the slag content is ≤0.5%.

4. The converter digestion and dust removal ash ball explosion prevention smelting method according to claim 1 is characterized in that: In step 3.1, the blowing intensity is controlled at 3.5-4.5 Nm 3 / min·t, the bottom blowing argon flow rate is controlled at 0.05-0.10Nm 3 / min·t, the ignition gun position for blowing is set at 1500mm, and the normal blowing gun position is 1400-1800mm. The slag-making material is added using a symmetrical silo, and the dust-collecting balls are added using a continuous feeding silo to ensure smooth addition of the dust-collecting balls and reduce the carbon-oxygen reaction caused by the dust-collecting balls.

5. The converter digestion dust removal ash ball explosion prevention smelting method according to claim 1 is characterized in that: The components and proportions of the dust removal balls described in step 3.2 are: TFe ≥ 50%, CaO ≥ 7%, SiO2 ≤ 5%, P ≤ 0.20%, S ≤ 0.20%, H2O ≤ 5%, surface strength ≥ 800N / piece, and the particle size range of the dust removal balls is 10-50mm, which is greater than 90%.

6. The converter digestion and dust removal ash ball explosion prevention smelting method according to claim 1 is characterized in that: The dust removal balls in step 3 melt relatively slowly. To prevent them from being fully melted and reduced, they must not be added 3 minutes before the end of smelting.

7. The converter digestion and dust removal ash ball explosion prevention smelting method according to claim 1 is characterized in that: The dust removal balls in step 3 have a certain carbon content. If too much is added during the double blowing, the CO concentration in the flue gas will increase sharply, which will bring the risk of explosion. Therefore, the amount of dust removal balls added during the double blowing should be controlled to be ≤ 1000kg, the excess can be made of lime or limestone; if the adjustment range is large, more than 1000kg of dust removal balls need to be added, and nitrogen curtain operation must be carried out.

8. The converter digestion and dust removal ash ball explosion prevention smelting method according to claim 1 is characterized in that: The weight percentages of the desulfurizing agent components in step 1 are: CaO ≥ 80.0%, SiO2 ≤ 5.0%, CaF2 ≥ 7.0%, S ≤ 0.040%, and the particle size of the desulfurizing agent is 0.2-1.5 mm.