Method for increasing silicon in molten iron and application
By adding ferrosilicon powder to the iron ditch during the steel smelting process, the problems of unstable silicon yield and complex equipment are solved, the silicon content in the iron is stable and the smelting cost is reduced, and the quality of molten steel and silicon are improved. Receiving rate.
Patent Information
- Application Number
- CN202411229031.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-03
- Publication Date
- 2024-12-06
AI Technical Summary
The silicon yield rate in the existing molten silicon increase method is unstable and the equipment is complex, which increases the smelting cost and affects the cleanliness and quality of the molten steel.
During the steel smelting process, ferrosilicon powder is added to the iron ditch after the slag skimmer. The addition rate of ferrosilicon powder is 10kg/min~20kg/min, the average particle size of ferrosilicon powder is 2mm~6mm, and the addition time is output After the 5th min to 8 min after the molten iron, the distance between the added height and the liquid surface of the molten iron is 80 mm to 120 mm, and the silicon content in the ferrosilicon powder is 68% to 72%, so as to improve the yield of silicon and reduce the smelting cost.
实现了铁水中硅含量的稳定提高,降低了转炉加发热剂和设备投入成本,提高了硅的收得率和铁水温度,降低了铁水单耗。
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of steel manufacturing, and in particular to a method for increasing silicon in molten iron and its application. Background Art
[0002] At present, in order to increase the output of molten steel, the scrap steel ratio is further increased during the smelting process, but it will cause the molten steel to be overoxidized, and the TFe content in the converter slag is high, which affects the cleanliness of the molten steel. The method to improve the cleanliness of molten steel is to increase the silicon content of molten iron. Siliconization of molten iron is a molten iron pretreatment process that adds ferrosilicon to molten iron to increase its silicon content to a predetermined value. Siliconization of molten iron is mainly used to increase silicon in low-silicon molten iron smelted in blast furnaces to make foundry pig iron, which saves energy and increases production of blast furnaces, and improves the cleanliness of molten steel and the quality of molten iron castings.
[0003] There are two main methods for increasing silicon in molten iron: one is to add ferrosilicon blocks after the slag skimmer during the blast furnace tapping process; the other is to spray ferrosilicon powder in the molten iron tank to increase silicon. The molten iron tank spraying method has low energy consumption and is easy to control, but the equipment is complex and the investment is large. However, the silicon recovery rate of these two methods for increasing silicon in molten iron is unstable, and the equipment invested for increasing silicon is relatively complex, which increases the smelting cost. Summary of the invention
[0004] To solve the above problems, the present application proposes a method for increasing silicon in molten iron, which can stabilize the quality of molten steel, reduce the cost of adding exothermic agents in the converter step (i.e., reduce smelting costs), and improve the silicon yield.
[0005] This application is implemented through the following technical solutions:
[0006] One of the purposes of the present application is to provide a method for increasing silicon in molten iron, comprising the steps of:
[0007] During the steelmaking process, ferrosilicon powder is added to the molten iron in the iron ditch behind the skimmer;
[0008] Wherein, the silicon content in the molten iron is less than 0.3%;
[0009] The adding rate of the ferrosilicon powder is 10kg / min to 20kg / min.
[0010] The method for increasing silicon in molten iron provided by the present application is to add ferrosilicon powder to the molten iron in the molten iron ditch. The ferrosilicon powder can not only increase the silicon content in the molten iron and stabilize the quality of the molten steel; and the iron powder is easy to melt and release heat, and can be used as a heat-generating agent, reducing the cost of adding heat-generating agents to the converter and reducing the investment cost of the injection equipment; in addition, the melting process of ferrosilicon powder is an exothermic reaction, and the ferrosilicon powder added to the molten iron has a high yield rate and a better heat release effect. The method can increase the temperature of the molten iron entering the converter by 4°C to 6°C, thereby reducing the unit consumption of molten iron. The addition rate can make the yield rate of silicon added to the ferrosilicon powder more than 80%, and the unit consumption of molten iron is less than 800kg / t.
[0011] In some possible implementations, the ferrosilicon powder is added starting from the 5th to 8th minute after the molten iron is discharged from the molten iron ditch, and the total adding time is 12 minutes to 20 minutes.
[0012] In some possible implementations, the total time of adding the ferrosilicon powder accounts for 14% to 71% of the total time of tapping the molten iron from the molten iron ditch.
[0013] In some possible implementations, the average particle size of the ferrosilicon powder is less than 6 mm.
[0014] In some possible implementations, the average particle size of the ferrosilicon powder is 2 mm to 6 mm.
[0015] In some possible implementations, the amount of ferrosilicon powder added is 1.0 kg / t to 2.0 kg / t.
[0016] In some possible implementations, the melting point of ferrosilicon powder is 1300°C to 1350°C.
[0017] In some possible implementations, the distance between the height of the added ferrosilicon powder and the surface of the molten iron is 80 mm to 120 mm.
[0018] In some possible implementations, the silicon content in the ferrosilicon powder is 68% to 72%.
[0019] The second purpose of the present application is to provide an application of the method for increasing silicon in molten iron provided in the present application in the field of steel smelting. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.
[0021] Obviously, the following descriptions are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in the field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.
[0022] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.
[0023] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.
[0024] The term "silicon recovery rate of ferrosilicon powder" refers to the percentage of the increase in silicon in molten iron to the content of added silicon. Due to losses, the actual recovery rate will be less than 100%. The calculation method is: recovery rate R = (increase in silicon in molten iron) / (content of added silicon) * 100%; where the content of added silicon = silicon content in ferrosilicon powder * amount of ferrosilicon powder added.
[0025] The term "hot metal consumption" refers to the amount of hot metal consumed to produce one ton of steel. The calculation formula is:
[0026] Unit consumption of molten iron = steel output (tons / kg) / molten iron consumption (tons).
[0027] The scrap steel ratio refers to the proportion of scrap steel used in steel production. my country's scrap steel ratio is 13.84%, far lower than the world average (37.6%) and the level of advanced developed countries (45% to 50%). This shows that there is still a lot of room for improvement in my country's scrap steel utilization.
[0028] In steel smelting with a large scrap ratio, due to the high scrap ratio, the molten steel is easily over-oxidized, resulting in a high TFe content in the converter slag, which affects the cleanliness of the molten steel. For steel smelting with a large scrap ratio, the temperature of the blast furnace is less than 1300℃, and ferrosilicon is added to the converter for supplementary heat. However, the melting time of ferrosilicon is long, and it is in the iron shell stage before it is completely melted, which is not conducive to dephosphorization and slag formation; further, an oxygen gun is required to oxidize the ferrosilicon floating on the surface of the molten iron, so that it releases heat on the surface; but this method makes it impossible to make good use of the heating effect of the ferrosilicon melting period.
[0029] In order to balance stabilizing the quality of molten steel, improving silicon recovery rate and reducing molten iron consumption, the embodiment of the present application proposes a method for increasing silicon in molten iron, which can reduce the molten iron consumption to less than 800 kg / t and the silicon recovery rate in ferrosilicon powder to more than 80%.
[0030] The following is a detailed description of a method for increasing silicon in molten iron and its application in an embodiment of the present application.
[0031] One of the purposes of the embodiments of the present application is to provide a method for increasing silicon in molten iron, comprising the steps of:
[0032] S1. During the steelmaking process, ferrosilicon powder is added to the molten iron in the iron ditch behind the skimmer;
[0033] Among them, the silicon content in the molten iron is less than 0.3%;
[0034] The addition rate of ferrosilicon powder is 10kg / min to 20kg / min.
[0035] The method for increasing silicon in molten iron provided in the embodiment of the present application is to add ferrosilicon powder to the molten iron in the molten iron trench. The ferrosilicon powder can not only increase the silicon content in the molten iron and stabilize the quality of the molten steel; and the iron powder is easy to melt and release heat, and can be used as a heat-generating agent to reduce the cost of adding heat-generating agents to the converter and reduce the investment cost of the injection equipment; in addition, the melting process of ferrosilicon powder is an exothermic reaction, and the ferrosilicon powder added to the molten iron has a high yield rate and a better heat release effect. This method can increase the temperature of the molten iron entering the converter by 4°C to 6°C, thereby reducing the unit consumption of molten iron. The addition rate can make the yield rate of silicon added with ferrosilicon powder more than 80%, and the unit consumption of molten iron is less than 800kg / t.
[0036] In the exemplary embodiment, the addition rate of ferrosilicon powder is 10kg / min to 20kg / min, and can be 10kg / min, 12kg / min, 15kg / min, 17kg / min, 18kg / min, 20kg / min, etc., typical but non-limiting rates or a range between any two rates. In this case, the addition rate of ferrosilicon powder avoids the incomplete melting of ferrosilicon powder caused by the agglomeration of ferrosilicon powder and improves the recovery rate of silicon in ferrosilicon powder.
[0037] In some specific embodiments, in the above step S1, ferrosilicon powder is added to the molten iron at a uniform speed. In this case, adding at a uniform speed can prevent too much addition at one time, and the ferrosilicon powder is wrapped by the molten iron, agglomerates, affects its melting effect, and thus improves its yield. In addition, adding at a uniform speed makes the ferrosilicon powder and the molten iron fully mixed, which is convenient for its dissolution.
[0038] In some embodiments, in the above step S1, the total time of adding ferrosilicon powder accounts for 14% to 71% of the total time of tapping molten iron from the molten iron ditch.
[0039] In some embodiments, in the above step S1, ferrosilicon powder is added at the 5th to 8th minute after the molten iron is discharged from the iron ditch, and the total time of addition is 12 minutes to 20 minutes. In this case, ferrosilicon powder is added in the middle stage of the molten iron (the early addition will make it difficult for the ferrosilicon powder to melt quickly, and it will float on the molten iron, and the heat of the ferrosilicon melting period cannot be used; the late addition of ferrosilicon powder will make the molten iron insufficient, and it will also cause the ferrosilicon powder to be difficult to melt quickly, float on the molten iron and remain in the iron ditch, thereby reducing the yield of ferrosilicon powder), which can increase the melting rate of ferrosilicon powder and synergistically improve the yield of ferrosilicon powder. It should be noted that the time when ferrosilicon powder is added after the molten iron is discharged from the iron ditch is related to the actual total time of the molten iron, and is not absolutely limited to the time of the embodiment of the present application, as long as it can be guaranteed that the addition is completed in the middle stage of the molten iron. As an example, ferrosilicon powder can be added within 5 to 20 minutes of molten iron being discharged from the iron ditch. This is based on 160 tons of molten iron being discharged from the iron ladle. According to the target silicon content, 150 to 300 kg of ferrosilicon powder needs to be added, and the molten iron tapping time is 30 to 35 minutes. In this case, ferrosilicon powder can be added within 5 to 20 minutes of molten iron being discharged from the iron ditch (i.e. in the middle of molten iron tapping), and the most suitable addition rate is less than 20 kg / min.
[0040] In the exemplary embodiment, ferrosilicon powder is added from 5 to 8 minutes after the molten iron is discharged from the iron ditch. The time for the start of the addition of ferrosilicon powder can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, and other typical but non-limiting start addition times or a range between any two start addition times. In this case, at 5 to 8 minutes after the molten iron is discharged from the iron ditch, the speed, temperature and amount of molten iron are all stable. At this time, the addition of ferrosilicon powder can make the ferrosilicon powder easily enter the molten iron and fully melt, thereby improving the recovery rate of silicon in the ferrosilicon powder.
[0041] In the exemplary embodiment, the total addition time of ferrosilicon powder is 12 min to 20 min, which may be a typical but non-limiting total addition time such as 12 min, 13 min, 14 min, 15 min, 18 min, 20 min, or a range between any two total addition times.
[0042] In some embodiments, in the above step S1, the average particle size of the ferrosilicon powder is less than 6 mm. In some embodiments, the average particle size of the ferrosilicon powder is 2 mm to 6 mm. In the exemplary embodiment, the average particle size can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, etc., which are typical but non-limiting average particle sizes, or a range between any two average particle sizes. In this case, the ferrosilicon powder is easy to melt in the molten iron and is not easy to be scattered and lost.
[0043] In some embodiments, in the above step S1, the amount of ferrosilicon powder added is 1.0kg / t to 2.0kg / t. In the exemplary embodiment, it can be a typical but non-limiting amount of 1.0kg / t, 1.2kg / t, 1.3kg / t, 1.5kg / t, 1.6kg / t, 2.0kg / t, etc. or a range between any two amounts. In this case, the content of silicon in the molten iron after adding the ferrosilicon powder is more than 0.32%. It should be noted that the amount of ferrosilicon powder added is related to the content of silicon in the molten iron and the target content of silicon in the final molten iron, and the target content of silicon in the final molten iron is more than 0.3%. Therefore, the amount of ferrosilicon powder added is adjusted according to the content of silicon in the original molten iron and the target content of silicon in the final molten iron, and is not absolutely limited to the amount of ferrosilicon powder added in the embodiment of the present application.
[0044] In some embodiments, in the above step S1, the distance between the height of the ferrosilicon powder added and the molten iron liquid level is 80 mm to 120 mm. In the exemplary example, it can be a typical but non-limiting distance of 80 mm, 100 mm, 110 mm, 115 mm, 120 mm, or a range between any two distances. In this case, the yield of the added ferrosilicon powder is more than 80%.
[0045] In some embodiments, in the above step S1, the mass fraction of silicon in the ferrosilicon powder is 68% to 72%. In the exemplary embodiment, it can be a typical but non-limiting mass fraction such as 68%, 70%, 72%, or a range between any two mass fractions. In this case, the melting point of the ferrosilicon powder is relatively low and can be quickly melted by the high temperature of the molten iron.
[0046] In some embodiments, in the above step S1, the melting point of the ferrosilicon powder is 1300° C. to 1350° C. In this case, the ferrosilicon powder is suitable for increasing silicon and / or supplementing heat in steel smelting with a large scrap steel ratio.
[0047] In some embodiments, a method for increasing silicon content in molten iron is provided, comprising the following steps:
[0048] S11. Determine the amount of ferrosilicon powder added based on the amount of iron discharged from the blast furnace and the silicon content in the molten iron.
[0049] S21. In the iron ditch area of the blast furnace, the height of the ferrosilicon powder added is set to be 80mm~120mm away from the molten iron surface.
[0050] S31. Start adding ferrosilicon powder 5 to 8 minutes after the molten iron is tapped, with an addition rate of 10 to 20 kg / min and a total addition time of 12 to 20 minutes.
[0051] The second purpose of the embodiment of the present application is to provide an application of the method for increasing silicon in molten iron provided in the embodiment of the present application in the field of steel smelting.
[0052] The following is further described in conjunction with specific embodiments.
[0053] Example 1
[0054] Example 1 provides a method for increasing silicon content in molten iron, comprising the following steps:
[0055] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.27%.
[0056] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm. According to the iron output and silicon content in (1), the amount of ferrosilicon powder added is determined to be 180 kg.
[0057] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 110 mm above the molten iron surface.
[0058] (4) After 5 minutes from the time when molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 18 kg / min for 10 minutes.
[0059] Example 2
[0060] Example 2 proposes a method for increasing silicon in molten iron, and the steps are basically the same as those in Example 1, except that:
[0061] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.22%.
[0062] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm. According to the iron output and silicon content in (1), the amount of ferrosilicon powder added is determined to be 260 kg.
[0063] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 115 mm above the molten iron surface.
[0064] (4) After 5 minutes after the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 17 kg / min for 15 minutes.
[0065] Example 3
[0066] Example 3 proposes a method for increasing silicon in molten iron, and the steps are basically the same as those in Example 1, except that:
[0067] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.22%.
[0068] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm. According to the iron output and silicon content in (1), the amount of ferrosilicon powder added is determined to be 240 kg.
[0069] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 120 mm above the molten iron surface.
[0070] (4) After 5 minutes after the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 17 kg / min for 15 minutes.
[0071] Example 4
[0072] Example 4 proposes a method for increasing silicon in molten iron, and the steps are basically the same as those in Example 1, except that:
[0073] In step (2), the addition rate of ferrosilicon powder is 20kg / min.
[0074] Example 5
[0075] Example 5 provides a method for increasing silicon content in molten iron, comprising the following steps:
[0076] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.27%.
[0077] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm. According to the iron output and silicon content in (1), the amount of ferrosilicon powder added is determined to be 260 kg.
[0078] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to a distance of 118 mm from the molten iron surface.
[0079] (4) Ferrosilicon powder was added 6 minutes after the molten iron was discharged from the iron ditch, with a rate of 18 kg / min and a duration of 14 minutes.
[0080] Example 6
[0081] Example 6 provides a method for increasing silicon content in molten iron, comprising the following steps:
[0082] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.24%.
[0083] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm. According to the iron output and silicon content in (1), the amount of ferrosilicon powder added is determined to be 230 kg.
[0084] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 115 mm above the molten iron surface.
[0085] (4) After the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 17 kg / min for 14 minutes.
[0086] Example 7
[0087] Example 7 provides a method for increasing silicon content in molten iron, comprising the following steps:
[0088] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.23%.
[0089] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm. According to the iron output and silicon content in (1), the amount of ferrosilicon powder added is determined to be 230 kg.
[0090] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 115 mm above the molten iron surface.
[0091] (4) 8 minutes after the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 15 kg / min for 15 minutes.
[0092] Comparative Example 1
[0093] Comparative Example 1 proposes a method for increasing silicon in molten iron, comprising the following steps:
[0094] (1) The blast furnace iron output is 160 tons, and the silicon content in the molten iron is 0.21%.
[0095] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm, and add 210 kg of ferrosilicon powder.
[0096] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 180 mm above the molten iron surface.
[0097] (4) After 5 minutes after the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 15 kg / min for 15 minutes.
[0098] Comparative Example 2
[0099] Comparative Example 2 proposes a method for increasing silicon in molten iron, comprising the following steps:
[0100] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.23%.
[0101] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm, and add 240 kg of ferrosilicon powder.
[0102] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 110 mm above the molten iron surface.
[0103] (4) After the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 40 kg / min for 6 minutes.
[0104] Comparative Example 3
[0105] Comparative Example 3 proposes a method for increasing silicon in molten iron, the steps are the same as those in Example 1, except that:
[0106] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.24%.
[0107] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 2 mm to 6 mm, and add 240 kg of ferrosilicon powder.
[0108] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 110 mm above the molten iron surface.
[0109] (4) 25 minutes after the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 24 kg / min for 10 minutes.
[0110] Comparative Example 4
[0111] Comparative Example 3 proposes a method for increasing silicon in molten iron, the steps are the same as those in Example 1, except that:
[0112] (1) The blast furnace output is 160 tons, and the silicon content in the molten iron is 0.27%.
[0113] (2) Select ferrosilicon powder with a silicon mass fraction of 72% and an average particle size of 8 mm, and the amount of ferrosilicon powder added is 230 kg.
[0114] (3) In the blast furnace tapping area, the height of ferrosilicon powder addition is set to be 110 mm above the molten iron surface.
[0115] (4) 7 minutes after the molten iron is discharged from the iron ditch, ferrosilicon powder is added at a rate of 18 kg / min for 13 minutes.
[0116] In order to verify the progressiveness of the method for increasing silicon in molten iron provided in the embodiment of the present application, the method for increasing silicon in molten iron provided in the embodiment and the comparative example adopts "GB / T 223.90-2021 Determination of silicon content in steel and alloys - Inductively coupled plasma atomic emission spectrometry" to measure the silicon content in ferrosilicon alloy, and "GB / T 223.79-2007 Determination of multi-element content in steel - X-ray fluorescence spectrometry (conventional method)" to detect and calculate the silicon content (mass fraction / %) in molten iron before and after adding ferrosilicon powder, and calculate the yield of ferrosilicon powder according to the silicon content; and then calculate the unit consumption of molten iron according to the method for increasing silicon in molten iron provided in the embodiment and the comparative example. The results are shown in Table 1 below.
[0117] Table 1
[0118]
[0119] From Table 1 above, we can at least draw the following conclusions:
[0120] (1) The method for increasing silicon in molten iron according to an embodiment of the present application can effectively increase and control the silicon content in molten iron.
[0121] (2) By using a method for increasing silicon in molten iron according to an embodiment of the present application, the silicon recovery rate in ferrosilicon powder is above 80%.
[0122] (3) It can be seen from Examples 1 to 7 and Comparative Example 1 that when the height of the ferrosilicon powder added is 80 mm to 120 mm from the molten iron liquid level, the recovery rate of the ferrosilicon powder can be significantly improved.
[0123] (4) It can be seen from Examples 1 to 7 and Comparative Example 2 that when the addition rate of ferrosilicon powder is 10 kg / min to 20 kg / min, the yield of ferrosilicon powder can also be significantly improved.
[0124] (5) It can be seen from Examples 1 to 7 and Comparative Example 3 that the timing of adding ferrosilicon powder after the molten iron is discharged from the molten iron ditch significantly affects the recovery rate of ferrosilicon powder. In Comparative Example 3, ferrosilicon powder is added from the 25th minute, which belongs to the middle and late stages of the molten iron being discharged from the molten iron ditch. The late addition of ferrosilicon powder will result in insufficient flushing of the molten iron, and will also make it difficult for the ferrosilicon powder to melt quickly, floating on the molten iron and remaining in the molten iron ditch, thereby reducing the recovery rate of ferrosilicon powder.
[0125] (6) It can be seen from Examples 1 to 7 and Comparative Example 4 that the average particle size of ferrosilicon powder also affects the yield of ferrosilicon powder. When ferrosilicon powder with an average particle size of 2 mm to 6 mm is melted in molten iron, it is not easy to be lost by drifting, and the yield of ferrosilicon powder is higher.
[0126] (7) It can be seen from Examples 1 to 7 and Comparative Examples 1 to 4 that the method for increasing silicon in molten iron according to an embodiment of the present application can increase the temperature of molten iron entering the converter.
[0127] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.
Claims
1. A method for increasing silicon in molten iron, characterized in that: Includes steps: During the steelmaking process, ferrosilicon powder is added to the molten iron in the iron ditch behind the skimmer; Wherein, the silicon content in the molten iron is less than 0.3%; The adding rate of the ferrosilicon powder is 10kg / min to 20kg / min.
2. The method for increasing silicon in molten iron according to claim 1, characterized in that: The ferrosilicon powder is added 5 to 8 minutes after the molten iron is discharged from the molten iron ditch, and the total adding time is 12 to 20 minutes.
3. The method for increasing silicon in molten iron according to claim 1, characterized in that: The total time of adding the ferrosilicon powder accounts for 14% to 71% of the total time of tapping molten iron in the molten iron ditch.
4. The method for increasing silicon in molten iron according to claim 1, characterized in that: The average particle size of the ferrosilicon powder is less than 6 mm.
5. The method for increasing silicon in molten iron according to claim 4, characterized in that: The average particle size of the ferrosilicon powder is 2 mm to 6 mm.
6. The method for increasing silicon in molten iron according to claim 1, characterized in that: The added amount of the ferrosilicon powder is 1.0kg / t to 2.0kg / t.
7. The method for increasing silicon in molten iron according to claim 1, characterized in that: The melting point of the ferrosilicon powder is 1300°C to 1350°C.
8. The method for increasing silicon in molten iron according to claim 1, characterized in that: The distance between the height of the ferrosilicon powder added and the surface of the molten iron is 80 mm to 120 mm.
9. The method for increasing silicon in molten iron according to any one of claims 1 to 8, characterized in that: The mass fraction of silicon in the ferrosilicon powder is 68% to 72%.
10. Use of the method for increasing silicon in molten iron as claimed in any one of claims 1 to 9 in the field of steel smelting.