A treatment method for preventing cold heading steel from being unable to be drawn out

Abstract

The present invention discloses a treatment method for preventing cold-heading steel from being unable to be drawn out, belonging to the technical field of iron and steel smelting. It mainly includes the following steps: after the molten steel enters the station, a small gear potential is used for power transmission throughout the process. After the power transmission is stable, lime, fluorite, synthetic slag and aluminum slag are added to the molten steel. This step, by adding lime, fluorite, synthetic slag and aluminum slag to the molten steel, can not only reduce the oxygen value of the molten steel, but also obtain a slag with better adsorption capacity. After the slag turns white, the slag making is completed; then, according to the acid-soluble aluminum in the first refining sample, aluminum is proportioned, and aluminum pellets and / or aluminum-calcium-carbon are added to the slag surface. By continuing power transmission, the reaction interface between the steel and the slag is increased, the alumina inclusions in the molten steel are adsorbed, and the content of alumina inclusions is reduced; finally, a calcium wire is fed under a weak blowing state to carry out calcification and modification treatment on the alumina inclusions in the molten steel, and then the purity of the molten steel is improved by soft blowing, the alumina inclusions are reduced, and the requirements for the pourability of the continuous casting molten steel are met.

Description

Technical Field

[0001] The present invention relates to the technical field of steel smelting, and more particularly, to a treatment method for preventing cold heading steel from being unable to be drawn out. Background Art

[0002] At present, there are many grades of cold heading steel. Taking SWRCH6A as an example, it belongs to low-carbon high-aluminum steel, and its composition is as follows: carbon 0.06%-0.08%, silicon 0-0.06%, manganese 0.2%-0.3%, phosphorus <0.2%, sulfur <0.12%, acid-soluble aluminum 0.025%-0.045%. Calculated based on a 120-ton converter, when smelting this steel grade in the converter, it is required to blow and draw carbon after the end-point sample to control the carbon to be less than 0.06%. The oxygen content of the molten steel will reach 800 ppm - 1200 ppm. Aluminum is added for deoxidation during tapping. The amount of aluminum added is calculated according to 1 kg of aluminum removing 3 ppm of oxygen. For example, if the end-point oxygen determination is 900 ppm, then 300 kg of aluminum needs to be added.

[0003] After tapping, the molten steel is transferred to the argon station for re-sampling and oxygen determination. According to the oxygen value, aluminum wire is fed and acid-soluble aluminum is adjusted to 0.04% - 0.06%. The deoxidation with aluminum wire is calculated as 1 meter removing 1 ppm, and then according to the acid-soluble aluminum content of the sampled composition, it is calculated as increasing 0.002% for every 10 meters to reach the required range. For example, if the oxygen determination at the argon station is 56 ppm, and after the sampling result comes out, the acid-soluble aluminum in the steel is 0.007%. If you want to adjust the acid-soluble aluminum in the steel to 0.05%, then the length of the aluminum wire to be fed is 56 * 1 + (0.05% - 0.007%) * 1000 / 0.2 = 56 + 215 = 271 meters.

[0004] After the molten steel is transferred to the LF furnace, aluminum wire is fed according to the sample at the argon station to adjust the acid-soluble aluminum to 0.06%, and then 200 kg of aluminum slag (containing 40% aluminum) is added. During the process, it is required to stir with argon at a flow rate of 100 cubic meters per hour for 3 - 5 minutes, and then sample again. According to the acid-soluble aluminum in the sample, it is adjusted to 0.04% - 0.045%. After the refining is completed, 200 meters of calcium wire is fed, and then soft blowing is carried out for 15 minutes or more before the molten steel can leave the station.

[0005] Due to the different bottom-blowing effects of each ladle, for some ladles, even if the argon gas flow rate is opened to the maximum, the argon gas can only achieve the effect of weak argon blowing. For ladles that do not meet the standard requirements, if the ladle replacement treatment is selected, it will definitely affect production and the quality of the molten steel, because during the ladle inversion process, the molten steel comes into contact with air, and a large amount of aluminum in the molten steel will be oxidized, resulting in a very high content of aluminum oxide. Removing aluminum oxide and ensuring the fluidity of the molten steel is a difficult problem. Even if the ladle is not inverted, the aluminum added in the converter and the argon station will also form a certain amount of aluminum oxide in the molten steel, and it is also a difficult problem to remove it when the argon gas does not meet the requirements. If not carefully handled, it is very likely that the molten steel cannot be drawn out during continuous casting.

[0006] In view of the above problems, it is necessary to provide a new treatment method for preventing cold heading steel from being unable to be drawn out. Summary of the Invention

[0007] The object of the present invention is to provide a treatment method for preventing cold heading steel from being unable to be drawn out in order to overcome the defects existing in the above-mentioned prior art.

[0008] The technical problem of the present invention is solved by adopting the following technical solutions.

[0009] An embodiment of the present invention provides a treatment method for preventing cold heading steel from being unable to be drawn out. When the bottom blowing argon of the ladle is in a weak blowing state of 15 - 35 cubic meters per hour, the treatment method for preventing cold heading steel from being unable to be drawn out includes the following steps: after the molten steel enters the station, select a small gear potential for power transmission. After the power transmission is stable, add lime, fluorite, synthetic slag and aluminum slag to the molten steel to make a white slag with good fluidity; then, according to the acid-soluble aluminum in the first refining sample, allocate aluminum, and add aluminum pellets and / or aluminum-calcium-carbon to adsorb the aluminum oxide inclusions in the molten steel; after feeding the calcium wire in the weak blowing state, soft blow for a period of time to complete the refining.

[0010] The present invention has the following beneficial effects:

[0011] The present invention provides a treatment method for preventing cold heading steel from being unable to be drawn out. When the bottom blowing argon of the ladle is in a weak blowing state of 15 - 35 cubic meters per hour, the treatment method for preventing cold heading steel from being unable to be drawn out includes the following steps: after the molten steel enters the station, select a small gear potential for power transmission throughout the process. After the power transmission is stable, add lime, fluorite, synthetic slag and aluminum slag to the molten steel. This step, by adding lime, fluorite, synthetic slag and aluminum slag to the molten steel, can not only reduce the oxygen value of the molten steel, but also obtain a slag with better adsorption ability. After the slag turns white, the slag making is completed; then, according to the acid-soluble aluminum in the first refining sample, allocate aluminum, add aluminum pellets and / or aluminum-calcium-carbon to the slag surface, and by continuing the power transmission, increase the steel-slag reaction interface, adsorb the aluminum oxide inclusions in the molten steel, and reduce the content of aluminum oxide inclusions; finally, feed the calcium wire in the weak blowing state to carry out calcification denaturation treatment on the aluminum oxide inclusions in the molten steel, and then improve the purity of the molten steel through soft blowing, reduce the aluminum oxide inclusions, and meet the castability requirements of the continuous casting molten steel. Detailed Embodiments

[0012] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those conditions not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0013] The following specifically describes a treatment method for preventing cold heading steel from being unable to be drawn out provided by an embodiment of the present invention.

[0014] In a first aspect, an embodiment of the present invention provides a treatment method for preventing cold heading steel from being unable to be drawn out. When the bottom blowing argon of the ladle is in a weak blowing state of 15 - 35 cubic meters per hour, the treatment method for preventing cold heading steel from being unable to be drawn out includes the following steps: After the molten steel enters the station, a small gear potential is selected for power supply. After the power supply is stable, lime, fluorite, synthetic slag, and aluminum slag are added to the molten steel to produce a white slag with good fluidity; then, aluminum is added according to the acid-soluble aluminum in the first refining sample, and aluminum pellets and / or aluminum-calcium-carbon are added to adsorb the alumina inclusions in the molten steel; after feeding the calcium wire in the weak blowing state, soft blowing is carried out for a period of time to complete the refining.

[0015] Currently, under normal circumstances, the treatment method of molten steel is relatively mature, and there will be no phenomenon that the molten steel cannot be drawn out according to the process operation. It only occurs when the bottom blowing of the ladle does not meet the standard.

[0016] When the bottom blowing argon effect of the ladle is only weak blowing or soft blowing argon, it is very difficult to remove alumina in the steel. From the end of refining to continuous casting and pouring of steel, it often starts to be unable to be drawn out as soon as the casting starts. Therefore, when the bottom blowing of the ladle does not meet the standard on site and there is no condition to pour the ladle or let the subsequent molten steel be cast on the casting machine first, only under the condition of reducing the casting machine gear, through the LF refining technology, the cold heading steel is treated under the condition of poor bottom blowing to achieve the purpose of smoothly pouring the molten steel.

[0017] Therefore, an embodiment of the present invention provides a treatment method for preventing cold heading steel from being unable to be drawn out. When the bottom blowing argon of the ladle is in a weak blowing state of 15 - 35 cubic meters per hour, the refining of cold heading steel mainly includes the following steps: After the molten steel enters the station, a small gear potential is selected for power supply throughout the process. After the power supply is stable, lime, fluorite, synthetic slag, and aluminum slag are added to the molten steel. This step can not only reduce the oxygen value of the molten steel but also obtain a slag with better adsorption ability by adding lime, fluorite, synthetic slag, and aluminum slag to the molten steel. After the slag turns white, the slag making is completed; then, aluminum is added according to the acid-soluble aluminum in the first refining sample, and aluminum pellets and / or aluminum-calcium-carbon are added to the slag surface. By continuously supplying power, the steel-slag reaction interface is increased to adsorb the alumina inclusions in the molten steel and reduce the content of alumina inclusions; finally, the calcium wire is fed in the weak blowing state to carry out calcification modification treatment on the alumina inclusions in the molten steel, and then the soft blowing is used to improve the purity of the molten steel and reduce the alumina inclusions to meet the castability requirements of the continuous casting molten steel.

[0018] In an alternative embodiment, the low-power power transmission gears are gears 11 - 8, and more preferably, the power transmission is at gear 11 throughout the process. After adding the slag materials, according to the molten steel temperature and production rhythm, gears 11 - 8 are selected for power transmission. If conditions permit, power transmission is carried out at gear 11 throughout the process. Since the bottom blowing argon in the ladle is small and the stirring effect is poor, at this time, using the electrode to carry out power transmission and stir the top slag is undoubtedly the best method to increase the steel-slag flow and allow the molten slag to adsorb alumina in the molten steel. Being able to carry out power transmission throughout the process is undoubtedly the maximum value for enhancing stirring. Therefore, when controlling the molten steel temperature, on-site personnel need to calculate the temperature rise amount and reasonably select the gears.

[0019] In an alternative embodiment, the amounts of slag materials are as follows: 500 kg of lime per 120 tons of steel, 400 kg of synthetic slag per 120 tons of steel, 200 kg of fluorite per 120 tons of steel, and 200 kg of aluminum slag per 120 tons of steel;

[0020] Preferably, the batch feeding method is as follows: 100 kg of synthetic slag + 20 kg of aluminum slag are added at a rate of one batch per minute until all the synthetic slag is added. Then, 100 kg of lime + 20 kg of aluminum slag are added at a rate of one batch per minute until all the lime is added. Finally, the fluorite and the remaining aluminum slag are added.

[0021] In an alternative embodiment, aluminum is added according to the acid-soluble aluminum in the first refining sample, and the amount of added aluminum is based on the upper limit of the acid-soluble aluminum range in the cold heading steel + 0 - 0.005%.

[0022] In an alternative embodiment, the addition amount of aluminum pellets is 20 - 30 kg per 120 tons of steel, and / or the addition amount of aluminum-calcium-carbon is 40 - 60 kg per 120 tons of steel;

[0023] Preferably, 4 - 6 kg of aluminum pellets are shoveled in at a rate of every 40 - 60 seconds, and / or 2 - 3 packages of 10 kg of aluminum-calcium-carbon are manually added per package. Let the electrode burn out the aluminum in the slag, so that the formed alumina dissolves in the slag, thereby improving the fluidity of the slag, increasing the steel-slag reaction rate, and increasing the adsorption of alumina in the steel. When manually adding aluminum pellets, the level of acid-soluble aluminum in the steel is not considered. Even if the acid-soluble aluminum in the steel exceeds 0.05%, manual addition is still required. Because after adding the slag materials, the slag will foam. Manually adding aluminum into the slag can, while deoxidizing, reduce the foaming degree of the slag and turn the slag white.

[0024] In an alternative embodiment, adding aluminum pellets and / or aluminum-calcium-carbon to adsorb alumina inclusions in the molten steel so that the content of alumina inclusions in the molten steel ≤ 0.001%. Sampling and testing to obtain the total aluminum and acid-soluble aluminum contents. The method for calculating the content of alumina inclusions is: Alt (total aluminum) - Als (acid-soluble aluminum).

[0025] In an alternative embodiment, it further includes: after removing alumina inclusions in the molten steel, if the sulfur content in the molten steel exceeds the sulfur content required by the steel grade composition, desulfurization treatment of the molten steel is required.

[0026] In an alternative embodiment, the desulfurization treatment of the molten steel includes the following steps: adding fluorite to improve the fluidity of the steel slag until the steel slag becomes white glassy slag. Under the power-on condition, when the temperature of the molten steel is greater than 1550 °C, calculate the power-on time according to the sulfur content of the refining sample - argon station sample until the sulfur is removed to the qualified range.

[0027] In an alternative embodiment, the mass ratio of lime to fluorite added is 90 - 100:50 - 60.

[0028] Preferably, the calculation method of the lime addition amount is: (refining sample - argon station sulfur content - target sulfur content) * 1000 / 0.025%.

[0029] Preferably, the calculation method of the power-on time is: (refining sample - argon station sulfur content - target sulfur content) / desulfurization rate, where the desulfurization rate is to remove (0.0007% - 0.0008%) per minute.

[0030] In an alternative embodiment, it further includes: after completing the control of the composition and temperature of the molten steel, feeding calcium wire to make the calcium content of the molten steel greater than 0.0012%, and then maintaining it for 15 - 20 minutes in a weak blowing state with an argon flow rate of 5 - 15 cubic meters per hour to complete the refining of cold heading steel.

[0031] The features and performance of the present invention will be further described in detail below in combination with embodiments.

[0032] Example 1

[0033] Taking SWRCH6A steel as an example, after the molten steel arrives at the LF furnace, turn the argon to the maximum, measure the temperature at 1537 °C, and it is found that the bottom blowing argon of the ladle can only reach the range of weak blowing argon (15 - 35 cubic meters per hour). The acid-soluble aluminum content of the argon station sample is 0.009%, the oxygen content of the argon station sample is 110 ppm, the sulfur content of the argon station sample is 0.020%, the target sulfur content is less than or equal to 0.012%. After feeding 110 * 1 + (0.05% - 0.009%) * 1000 / 0.2 = 110 + 205 = 325 meters of aluminum wire at the argon station, blow argon for 3 minutes to homogenize the composition, and then take a sample and leave the station.

[0034] The refining of SWRCH6A steel includes the following steps (the following material consumption is based on 120 tons of steel):

[0035] 1. After the molten steel enters the station, no slag materials are added. Then, power is supplied at the 11th gear. After the power supply is stable, slag materials are added, including 500 kg of lime, 400 kg of synthetic slag, 200 kg of fluorite, and 200 kg of aluminum slag. The feeding method is as follows: 100 kg of synthetic slag + 20 kg of aluminum slag, and the slag materials are added at a rate of one batch per minute until all the synthetic slag is added. Then, 100 kg of lime + 20 kg of aluminum slag are added until all the lime is added. Finally, the fluorite and aluminum slag are added. Check the color of the adhering slag on-site. If it is white, it indicates good deoxidation. If the color of the slag is dark green or black, it indicates poor deoxidation, and aluminum particles need to be added during power supply until the slag turns white. If it is glassy slag, lime needs to be supplemented until it becomes white and opaque slag.

[0036] 2. After adding the slag materials, continue to supply power for 2 - 3 minutes and then take Sample 1. The composition of Sample 1 is acid-soluble aluminum 0.038% and sulfur 0.017% (during the process of treating molten steel in the early stage of refining, the acid-soluble aluminum in the molten steel will change due to the size of argon gas and the oxygen content in the slag or molten steel, and the sulfur content in the steel will also decrease due to the degree of deoxidation and the size of argon gas. Therefore, as long as the above operations are carried out, the sulfur in the steel will definitely decrease to some extent). According to the acid-soluble aluminum in the refining Sample 1, aluminum is proportioned, and 50 meters of aluminum wire is fed to make it reach 0.048%. If it is higher than 0.05%, no aluminum needs to be proportioned. Because the molten steel has been deoxidized in the early stage, if the argon gas is small, the aluminum in the steel is difficult to be oxidized, so it can be controlled at the upper limit of the range.

[0037] 3. After proportioning aluminum, 4 - 6 kg of aluminum particles are shoveled in at a speed of 40 - 60 seconds per time on-site, and / or 2 - 3 packages of aluminum-calcium-carbon with 10 kg per package are manually added. In this step, while supplying power at the 11th gear, aluminum-calcium-carbon or floating aluminum particles are added, allowing the deoxidizer to melt in the slag. The process will cause the slag to foam. Under the reaction force of bottom blowing and electrode slag pushing, it promotes the flow of the slag and adsorbs aluminum oxide. The power supply process requires 10 minutes or more.

[0038] 4. After the slag turns white, fluorite is added to improve the fluidity of the slag until it becomes white glassy slag. Generally, the ratio of lime to fluorite is 90 - 100:50 - 60.

[0039] 5. After making the white glassy slag, under the condition of supplying power at the 11th gear, when the temperature of the molten steel is greater than 1550 °C, the desulfurization speed is 0.0007% - 0.0008% per minute. Calculate the power supply time according to the sulfur content in the argon station sample until the sulfur is removed to the qualified range. For example, to reduce from 0.017% to below 0.012%, it needs to remove (0.017% - 0.012%) = 0.005%, and it takes 0.005% / 0.0007% = 7.14 minutes. Take Sample 2. The composition of Sample 2 is acid-soluble aluminum 0.042%, total aluminum 0.043%, and sulfur 0.0118%, meeting the requirements.

[0040] 6. After the above steps are completed and the composition and temperature of the molten steel are controlled, the molten steel is subjected to calcium treatment. 180 meters of calcium wire is fed in to make the calcium content in the molten steel greater than 0.0012%, and it is kept in the soft blowing state for more than 15 minutes. A sample is taken at the end of refining. The acid-soluble aluminum in the composition is 0.040%, the total aluminum is 0.041%, the sulfur is 0.011%, and the calcium is 0.015%. Then it is discharged from the refining station.

[0041] Comparative Example 1

[0042] The steps are similar to those of Example 1, with the only difference being that the dosage of aluminum pellets is 45 - 60 kg / 120 tons of steel. The results are as follows: The acid-soluble aluminum at the time of discharging from refining is 0.055%, exceeding the composition range. Because a large amount of aluminum is added, surely a part of it will enter the molten steel to form acid-soluble aluminum. The molten steel has been deoxidized in the early stage, and it is difficult for the acid-soluble aluminum in the molten steel to be oxidized. In addition, as the amount of aluminum added increases, the content of aluminum oxide in the slag is too high, which will also affect the ability to adsorb inclusions. Because the larger the value of calcium oxide:aluminum oxide, the stronger the adsorption ability, but the stronger the fluidity, the slower the adsorption speed. On the contrary, the fluidity is very good, but the ability to adsorb inclusions is poor. The on-site control is based on a white slag, slightly making the slag foam, and mainly appropriately increasing the aluminum oxide in the slag. With the addition amount of Example 1, the calcium oxide is generally 54% - 60%, and the aluminum oxide is generally 24% - 31%. For Comparative Example 1, when 60 kg is added, the aluminum oxide will exceed 33%, and the slag becomes glassy, with poor viscosity and the adsorption ability is not as strong as that of Example 1.

[0043] Comparative Example 2

[0044] The steps are similar to those of Example 1, with the only difference being that the dosage of aluminum pellets is 5 - 10 kg / 120 tons of steel. The results are as follows: The acid-soluble aluminum is 0.039%, the total aluminum is 0.041%, and the aluminum oxide in the steel is 0.002%. This increases the risk that the molten steel cannot be drawn out. If the calcium treatment amount is increased by feeding more calcium wire to wash away the aluminum oxide sticking to the continuous casting nozzle with calcium, the erosion of the continuous casting nozzle by calcium in the molten steel will be aggravated, especially when the calcium is greater than 0.025%, which is more obvious, thus reducing the service life and the number of production furnaces. On the other hand, adding an appropriate amount of aluminum to the slag is used to increase the slag-steel reaction interface. If less is added, the slag does not foam enough and the fluidity is not good enough, which will also affect the desulfurization of the molten steel.

[0045] Comparative Example 3

[0046] Similar to the steps of Example 1, the only difference is that: based on the acid-soluble aluminum in the refined sample 1, after adding aluminum, the acid-soluble aluminum content is 0.038%. The result is that the acid-soluble aluminum at the station is 0.027%, approaching the lower limit of the range. If the aluminum loss is a bit larger during the continuous casting pouring process, that is, the burning loss is greater than 7.4%, then the aluminum in the steel will be less than 0.025%, exceeding the composition range. In addition, when the aluminum in the molten steel is low, the desulfurization rate will also decrease accordingly, meaning that it takes longer to desulfurize, which has an impact on both temperature and rhythm control. It is acceptable not to consider efficiency when there is plenty of time.

[0047] Comparative Example 4

[0048] Similar to the steps of Example 1, the only difference is that: after adding the slag materials, without checking the slag for non-sticking slag, directly taking a sample 1. If it is black slag, and the refined aluminum is adjusted according to sample 1, then the alumina in the molten steel will be very high, increasing the difficulty of removal in the later stage and increasing the risk of the molten steel not being able to be drawn out.

[0049] Comparative Example 5

[0050] Similar to the steps of Example 1, the only difference is that: after adjusting the aluminum according to sample 1, directly sending power at a large gear, and then feeding the calcium wire. If the power is not continued to add aluminum to protect the slag, and the alumina is removed through the steel-slag reaction, then the alumina will not be removed completely, resulting in the steel not being able to be drawn out.

[0051] In summary, a treatment method for preventing cold heading steel from not being drawn out provided by the embodiments of the present invention mainly includes the following steps: after the molten steel enters the station, select a small gear potential to send power. After the power supply is stable, add lime, fluorite, synthetic slag, and aluminum slag to the molten steel. When the slag becomes white, the slag making is completed; then adjust the aluminum according to the acid-soluble aluminum in the refined sample 1, add aluminum pellets and / or aluminum calcium carbon to the slag surface, and by continuously sending power, increase the reaction interface between the steel and the slag, adsorb the alumina inclusions in the molten steel, and reduce the content of alumina inclusions; finally, feed the calcium wire under the weak blowing state to carry out calcification modification treatment on the alumina inclusions in the molten steel, and then improve the purity of the molten steel through soft blowing, reduce the alumina inclusions, and meet the castability requirements of the continuous casting molten steel.

[0052] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A treatment method for preventing cold heading steel from being unable to be drawn out, characterized in that When the ladle is in a weak argon blowing state of 15 - 35 cubic meters per hour, the treatment method to prevent cold heading steel from not being drawn out includes the following steps: After the molten steel enters the station, select a small gear position for power supply. After the power supply is stable, add lime, fluorite, synthetic slag, and aluminum slag to the molten steel to produce a white slag with good fluidity; then, according to the acid-soluble aluminum in the first refining sample, allocate aluminum. Add aluminum pellets and / or aluminum-calcium-carbon to adsorb the aluminum oxide inclusions in the molten steel; after feeding the calcium wire in the weak blowing state, soft blow for a period of time to complete refining, where: The small gear position for power supply is gear 11 - 8; Allocate aluminum according to the acid-soluble aluminum in the first refining sample. The amount of allocated aluminum is based on the upper limit of the acid-soluble aluminum range in the cold heading steel + 0 - 0.005%. After removing the aluminum oxide inclusions in the molten steel, if the sulfur content in the molten steel exceeds the sulfur content required by the steel grade composition, desulfurization treatment of the molten steel is required; After completing the control of the composition and temperature of the molten steel, feed the calcium wire to make the calcium content of the molten steel greater than 0.0012%, and then maintain it for 15 - 20 minutes in a soft blowing state with an argon flow rate of 5 - 15 cubic meters per hour to complete the refining of cold heading steel.

2. The processing method according to claim 1, characterized in that The power supply gear is at gear 11 for the whole process.

3. The processing method according to claim 1, characterized in that The dosage of slag materials is: 500 kg of lime per 120 tons of steel, 400 kg of synthetic slag per 120 tons of steel, 200 kg of fluorite per 120 tons of steel, and 200 kg of aluminum slag per 120 tons of steel.

4. The processing method according to claim 3, characterized in that, The batch feeding method is as follows: 100 kg of synthetic slag + 20 kg of aluminum slag, added at a rate of one batch per minute until all the synthetic slag is added, then 100 kg of lime + 20 kg of aluminum slag, added at a rate of one batch per minute until all the lime is added, and finally add all the fluorite and the remaining aluminum slag.

5. The processing method according to claim 1, characterized in that The addition amount of the aluminum pellets is 20 - 30 kg per 120 tons of steel, and / or the addition amount of the aluminum-calcium-carbon is 40 - 60 kg per 120 tons of steel.

6. The processing method according to claim 5, wherein Shovel in 4 - 6 kg of aluminum pellets at a speed of every 40 - 60 seconds, and / or hand-feed 2 - 3 bags of 10 kg of aluminum-calcium-carbon per bag.

7. The processing method according to claim 5, wherein Add aluminum pellets and / or aluminum-calcium-carbon to adsorb the aluminum oxide inclusions in the molten steel so that the content of aluminum oxide inclusions in the molten steel ≤ 0.001%.

8. The processing method according to claim 1, wherein The desulfurization treatment of the molten steel includes the following steps: Add lime and fluorite to increase the alkalinity of the steel slag and maintain good fluidity until the steel slag becomes white glassy slag. Under the power supply condition, when the temperature of the molten steel is greater than 1550°C, calculate the power supply time according to the sulfur content in the first refining sample until the sulfur is removed to the qualified range.

9. The processing method according to claim 8, characterized in that, The mass ratio of the added lime to the fluorite is 90 - 100:50 - 60.

10. The processing method according to claim 9, characterized in that, The calculation method for the addition amount of the lime is: (sulfur content in the first refining sample - target sulfur content) * 1000 / 0.025%.

11. The processing method according to claim 9, characterized in that, The calculation method for the power supply time is: (sulfur content in the first refining sample - target sulfur content) / desulfurization speed, where the desulfurization speed is to remove (0.0007% - 0.0008%) per minute.