A method of suppressing spitting in a direct reduced iron (DRI) process

Abstract

The application discloses a method for inhibiting spitting in a DRI smelting converter process, and belongs to the technical field of iron and steel metallurgy. In view of the problem that after direct reduced iron (DRI) is added into a converter, severe spitting is caused by the fact that the content of FeO in slag fluctuates sharply and the slag layer foams, the application provides a method for inhibiting spitting in a DRI smelting converter process, which comprises the following steps: firstly, DRI is added into the converter, then semi-steel is added, and then an oxygen lance is lowered to perform top blowing smelting; the highest lance position is adopted in the whole blowing refining process at the beginning of blowing, batched slag-making materials are added in the early stage of blowing refining, and the oxygen lance position is gradually lowered, the lance position is lifted in the middle stage of blowing refining, and the lance position is lowered again in the late stage of blowing refining and is maintained until the end of blowing refining. By adopting the method, the spitting occurrence rate of the DRI smelting converter process is significantly reduced, and the smelting endpoint hit rate is not affected, and the method is suitable for a DRI added converter steelmaking process.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, specifically relating to a method for suppressing splashing during the DRI process in converter smelting. Background Technology

[0002] Direct reduced iron (DRI), as a high-quality substitute for scrap steel, is increasingly widely used in converter steelmaking. DRI has advantages such as stable chemical composition and low levels of harmful impurities, making it particularly suitable for smelting high-quality steels. However, during converter blowing, the high FeO and gangue content in DRI, when added to the molten pool, significantly increases the FeO content in the slag, easily leading to excessive slag foaming and severe slag splashing. This splashing not only causes metal and heat loss, increased steel feed consumption, and slag adhesion at the furnace mouth and cap, but can even cause negative torque or safety accidents in the converter, severely restricting the safe, large-scale application of DRI in converters.

[0003] To suppress converter splashing, various methods have been proposed in the prior art. Patent CN118726691A discloses a method for preventing low-temperature splashing in converters. This method determines the temperature by detecting the CO content in the furnace. When the CO content is below a set value, a splashing inhibitor containing Si or Al is added, and the lance position is lowered by 100-300 mm to suppress splashing caused by the accumulation of iron oxide in the slag under low-temperature conditions. This method relies on the reaction between the splashing inhibitor and the iron oxide in the slag, requiring the addition of a special inhibitor, increasing auxiliary material costs. Patent CN121674645A discloses a method for suppressing splashing during high scrap ratio converter smelting. This method involves slag retention, charging, and segmented control of the lance position in the early (1250-1350 mm), middle (1550-1650 mm), and late (1350-1450 mm) stages of blowing. Simultaneously, the first batch of slag-forming material is added when the lance position is raised in the middle stage, achieving synergy between oxygen supply and slag formation. This method is designed for smelting with a high scrap ratio (≥25%), but the physicochemical properties of scrap steel differ significantly from those of DRI (Dry Refined Iron). Therefore, the lance positioning (low-high-middle) and slag formation timing in this method are not applicable to DRI heats. Furthermore, patent CN207143282U provides a converter device to prevent slag splashing. This device uses a compressed gas main pipe and refractory nozzle bricks installed on the outer wall of the converter to blow compressed gas onto the surface of the foamed slag, physically suppressing the splashing. This solution is an equipment improvement that requires modification of the converter itself, resulting in significant investment and complex maintenance.

[0004] Patent CN119372395A discloses a converter smelting method using direct reduced iron (DRI). DRI is added to the converter along with scrap steel at a rate of 10-150 kg / t. The lance position is 1500-2200 mm during the first 0-5 minutes of blowing, 1700-2500 mm during the last 5-10 minutes, and 1300-2000 mm after the last 10 minutes. The addition of coolant and slagging agent is controlled in stages to address issues of re-drying and incomplete scrap melting. This method involves smelting DRI with scrap steel in combination with ordinary molten iron, with three-stage lance position control. However, it does not address the issue of repeated foam slag splashing during the smelting of DRI with semi-finished steel.

[0005] In summary, existing technologies for addressing splashing issues in converter processes either rely on additional additives and equipment modifications, or employ lance position modes designed for ordinary scrap steel. Neither adequately addresses the characteristics of drastic FeO fluctuations and repeated foam slag formation in the slag during DRI melting. Therefore, it is necessary to provide a smelting method that optimizes the oxygen lance position control curve and coordinates it with the slag-forming material addition node to effectively suppress splashing during the converter smelting DRI process, which has significant industrial application value. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the present invention provides a method for suppressing splashing during the DRI (Distillation-Release Injection) process in converter smelting. This method aims to suppress the unique foamy slag splashing characteristic of DRI heats by optimizing oxygen lance position control and the timing of slag-forming material addition, addressing the characteristics of drastic FeO fluctuations and repeated foamy slag formation in the slag during the DRI melting process. This reduces steel material consumption and improves smelting safety and endpoint hit rate.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for suppressing splashing during the DRI process in a converter smelting, the smelting method comprising the following steps: Step 1: First, add DRI into the converter, then add semi-steel, and then lower the oxygen lance for top-blown smelting. Step 2: Start the blowing process. The oxygen lance position at the start of the blowing process is the highest position of the lance throughout the entire blowing process. Step 3: In the early stage of blowing, the slag-forming material is added in batches, and the oxygen lance position is gradually lowered; Step 4: In the middle stage of refining, raise the oxygen lance position to a higher level than the lance position at the end of the early stage of refining; Step 5: In the later stage of the forging process, lower the gun position again to a level comparable to the gun position at the end of the early stage of the forging process, and maintain this gun position until the end of the forging process.

[0008] Furthermore, in step two, the oxygen lance position is controlled at 1850mm~2050mm during the initial blowing; in step three, the position is lowered to 1500mm~1850mm, and then dynamically adjusted to 1150mm~1450mm; in step four, the position is raised to 1700mm~1900mm; and in step five, the position is lowered to 1250mm~1450mm.

[0009] Further, the semi-steel composition in step one is: C: 2.90%~3.70%, Si: 0.02%~0.06%, Mn: 0.02%~0.07%, P: 0.08%~0.16%, S: 0.02%~0.15%, V: 0.02%~0.06%, with the remainder being Fe.

[0010] Furthermore, the amount of DRI added in step one is ≤90kg / t.

[0011] Furthermore, the flow rate of top-blown oxygen mentioned in step one is 26000 Nm³ / h to 28000 Nm³ / h during the blowing stage.

[0012] Furthermore, the slag-forming material consists of lime, dolomite, and magnesium spheres, and is added in three batches: In the first batch, when the gun position was lowered to 1600mm~1800mm in the early stage of smelting, dolomite and lime were added; In the second batch, when the gun position is lowered to 1500mm~1700mm in the early stage of blowing, magnesium balls, dolomite and lime are added; In the third batch, when the gun position is raised to 1750mm~1850mm during the middle stage of smelting, the remaining dolomite and lime are added.

[0013] Furthermore, the total amount of dolomite added is 13 kg / t to 18 kg / t, and the total amount of lime added is 16 kg / t to 22 kg / t.

[0014] Furthermore, the smelting method is applied to the process route of BOF+Ar station+LF+CC or BOF+Ar station+CC.

[0015] Furthermore, the final temperature of the converter smelting is controlled at 1560℃~1660℃, the slag basicity is controlled at 3.0~6.0, and the FeO mass fraction in the slag is controlled at 15%~30%.

[0016] Furthermore, the early stage of blowing is from the start of blowing to 4 minutes of blowing, the middle stage of blowing is from 4 minutes to 8 minutes of blowing, and the late stage of blowing is from 8 minutes of blowing to the end of blowing.

[0017] Compared with existing technologies, this invention has the following beneficial effects: Significantly suppresses splashing: By using a special lance position curve of "high lance position during initial blowing → gradually lowering the lance as slag is formed → rapidly raising the lance in the middle and later stages → lowering the lance again before final blowing," it actively matches the fluctuation pattern of FeO in the slag during DRI melting, avoiding concentrated bursts of decarburization reaction and significantly reducing the splashing rate; This invention can be achieved simply by optimizing the oxygen lance position control curve and combining it with the normal addition of existing slag-forming materials, resulting in low modification costs, simple operation, and easy promotion; In this invention, the lance position and the timing of slag-forming agent addition are coordinated, maintaining the slag basicity and oxidizing properties within a suitable range, providing favorable conditions for dephosphorization during the smelting process. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the oxygen lance position-blowing time control curve according to an embodiment of the present invention.

[0019] Figure 2 This is a process flow diagram of the method for suppressing splashing during the DRI process of converter smelting according to the present invention. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 2 As shown, the overall process of the method described in this invention is as follows: first, DRI is added into the converter, then semi-steel is added, the oxygen lance is lowered and blowing begins, and then the lance position is adjusted in stages according to the early stage of blowing, the middle stage of blowing, and the late stage of blowing, and slag-forming materials are added in batches until the steel is tapped at the end of the blowing process.

[0022] Figure 1 In the figure, the horizontal axis represents the blowing time t (min), and the vertical axis represents the oxygen lance position H (mm). The two vertical dashed lines divide the blowing process into three stages: early blowing, middle blowing, and late blowing. The five diagonal lines represent the adjustable range of the oxygen lance position for each blowing stage: 1850mm~2050mm in the initial blowing stage; in the early blowing stage, the position is first lowered to 1500mm~1850mm, then dynamically adjusted to 1150mm~1450mm; in the middle blowing stage, the position is raised to 1700mm~1900mm; and in the late blowing stage, the position is lowered again to 1... 250mm~1450mm, and maintain this lance position until the end of the blowing process; the solid line in the figure is the actual control curve of the oxygen lance position in Example 1, and the hollow dots and marked values ​​on the curve are the actual lance positions of each control node in Example 1; the lance position curve generally shows the trend of "high lance position at the start of blowing → gradually lowering the lance in the early stage of blowing → raising the lance in the middle stage of blowing → lowering the lance again in the later stage of blowing and maintaining it until the end of the blowing process"; ①, ②, and ③ in the figure represent the addition nodes of the first batch of slag-forming materials (dolomite + lime), the second batch of slag-forming materials (magnesium balls + dolomite + lime) and the third batch of slag-forming materials (remaining dolomite + lime), respectively.

[0023] In this invention, the early stage of blowing is from the start of blowing to 4 minutes of blowing, the middle stage of blowing is from 4 minutes to 8 minutes of blowing, and the late stage of blowing is from 8 minutes of blowing to the end of blowing.

[0024] After DRI is added to the converter, its FeO and gangue components enter the slag phase, significantly increasing the FeO content in the slag. In the early stage of blowing, DRI melts intensively, and the decarburization reaction is superimposed on the reduction reaction of FeO in the slag, making the slag layer prone to excessive foaming. A higher lance position of 1850mm~2050mm is used during the initial blowing stage, resulting in a softer impact of the oxygen jet on the molten pool, which is conducive to the rapid formation of initial slag and avoids splashing in the early blowing stage. In the early blowing stage, the lance position is gradually lowered to 1150mm~1450mm as slag-forming materials are added in batches to enhance molten pool stirring, control the decarburization reaction rate during the DRI melting stage, and inhibit excessive foam slag formation. In the middle stage of blowing, the lance position is raised to 1700mm~1900mm to increase the supply of FeO in the slag, promote slag formation, and prevent slag from drying out. In the later stage of blowing, the lance position is lowered again to 1250mm~1450mm and maintained until the end of the blowing process to promote uniform stirring of the molten pool and ensure the success rate of the smelting endpoint.

[0025] Those skilled in the art will understand that fluctuations in lance position within the aforementioned range based on furnace volume and conditions are normal operational adjustments. It should be emphasized that while existing technologies disclose the lance position operation range for individual stages (such as high lance position slag control at 1800mm~1900mm during converter blowing, high lance position slag control at 1800mm~2200mm during the middle stage of smelting, and low lance position carbon extraction at approximately 1300mm at the end of smelting), they do not disclose the overall lance position curve described in this invention: highest lance position throughout the blowing process → gradually decreasing lance position in the early stage of blowing → increasing lance position in the middle stage of blowing → decreasing lance position again in the later stage of blowing. Furthermore, they do not disclose the synergistic relationship between this lance position curve and the batch addition of slag-forming materials, nor do they disclose the specific charging sequence of adding DRI first and semi-steel later. The innovation of this invention lies in the synergistic effect of the above-mentioned gun position curve trend, the order of DRI addition, and the three-batch addition of slag-forming material, which actively matches the fluctuation pattern of FeO in the slag during the DRI melting process, thereby effectively suppressing foamy slag splashing. The technical effect achieved by the overall combination of these technical features is unpredictable by a simple combination of gun position ranges at each stage.

[0026] Example 1 This embodiment takes the converter smelting process of HRB500E steel as an example. The process flow is: 120t BOF + Ar station + CC. The specific steps are as follows: Step 1: Add 9.33t of DRI and 136t of semi-steel sequentially to the converter. The amount of DRI added can be ≤90kg / t, and in this embodiment, 62kg / t is preferred. The flow rate of top-blown oxygen during the blowing stage can be 26000Nm³ / h~28000Nm³ / h, and in this embodiment, 27800Nm³ / h is preferred. The composition of the added semi-steel can be within the range of C: 2.90%~3.70%, Si: 0.02%~0.06%, Mn: 0.02%~0.07%, P: 0.08%~0.16%, S: 0.02%~0.15%, V: 0.02%~0.06%, and in this embodiment, C: 3.65%, Si: 0.0452%, Mn: 0.066%, P: 0.154%, S: 0.0204%, V: 0.036%, with the remainder being Fe.

[0027] Step 2: When starting the oxygen lance, the position of the lance can be within the range of 1900mm~2000mm, and in this embodiment, 1941mm is preferred; Step 3: Blowing for ≤4 minutes, lowering the lance position to within the range of 1600mm~1800mm, preferably 1741mm in this embodiment. Add the first batch of slag-forming materials, including 944kg of dolomite and 900kg of lime. Continue lowering the lance position, which can be within the range of 1500mm~1700mm, preferably 1680mm in this embodiment. Add the second batch of slag-forming materials, including 250kg of magnesium balls, 930kg of lime, and 1000kg of dolomite. Subsequently, the lance position can be further dynamically adjusted to within the range of 1200mm~1400mm, preferably 1370mm in this embodiment. The total amount of dolomite added can be within the range of 13kg / t~18kg / t, and the total amount of lime added can be within the range of 16kg / t~22kg / t; preferably 2144kg of dolomite and 2230kg of lime in this embodiment.

[0028] Step 4: Blow for 4-8 minutes, raising the gun position to a range of 1750mm-1850mm. In this embodiment, 1770mm is preferred. Add the third batch of slag-forming materials, including 200kg of dolomite and 400kg of lime.

[0029] Step 5: Blow for 8-12 minutes, then lower the gun position again to within the range of 1300mm-1400mm. In this embodiment, 1380mm is preferred, and maintain this gun position until the end of the blowing process.

[0030] Following the above steps, the HRB500E smelting process in the converter was stable, with no significant splashing. The final smelting temperature in the converter can be within the range of 1560℃ to 1660℃, with 1660℃ being preferred in this embodiment; the slag basicity can be within the range of 3.0 to 6.0, with 5.6 being preferred in this embodiment; and the FeO mass fraction in the slag can be within the range of 15% to 30%, with 19.23% being preferred in this embodiment.

[0031] Example 2 This embodiment takes the converter smelting process of HRB500E steel as an example. The process flow is: 120t BOF + Ar station + CC. The specific steps are as follows: Step 1: Add 10.94t of DRI and 137t of semi-steel sequentially to the converter. The amount of DRI added can be ≤90kg / t, and in this embodiment, 80kg / t is preferred. The flow rate of top-blown oxygen during the blowing stage can be 26000Nm³ / h~28000Nm³ / h, and in this embodiment, 27500Nm³ / h is preferred. The composition of the added semi-steel can be within the range of C: 2.90%~3.70%, Si: 0.02%~0.06%, Mn: 0.02%~0.07%, P: 0.08%~0.16%, S: 0.02%~0.15%, V: 0.02%~0.06%, and in this embodiment, C: 3.45%, Si: 0.035%, Mn: 0.040%, P: 0.13%, S: 0.015%, V: 0.056%, with the remainder being Fe.

[0032] Step 2: When starting the oxygen lance, the position of the lance can be within the range of 1900mm to 2000mm, and in this embodiment, 1990mm is preferred; Step 3: Blowing for ≤4 minutes, lowering the lance position to within the range of 1600mm~1800mm, preferably 1750mm in this embodiment. Add the first batch of slag-forming materials, including 800kg of dolomite and 300kg of lime. Continue lowering the lance position, which can be within the range of 1500mm~1700mm, preferably 1640mm in this embodiment. Add the second batch of slag-forming materials, including 230kg of magnesium balls, 950kg of lime, and 900kg of dolomite. Subsequently, the lance position can be further dynamically adjusted to within the range of 1200mm~1400mm, preferably 1347mm in this embodiment. The total amount of dolomite added can be within the range of 13kg / t~18kg / t, and the total amount of lime added can be within the range of 16kg / t~22kg / t; preferably 2000kg of dolomite and 2200kg of lime in this embodiment.

[0033] Step 4: Blow for 4-8 minutes, raising the gun position to a range of 1750mm-1850mm. In this embodiment, 1816mm is preferred. Add the third batch of slag-forming materials, including 300kg of dolomite and 950kg of lime.

[0034] Step 5: Blow for 8-12 minutes, then lower the gun position again to within the range of 1300mm-1400mm. In this embodiment, 1362mm is preferred, and maintain this gun position until the end of the blowing process.

[0035] Following the above steps, the HRB500E smelting process in the converter was stable, with no significant splashing. The final smelting temperature in the converter can be within the range of 1560℃ to 1660℃, with 1639℃ being preferred in this embodiment; the slag basicity can be within the range of 3.0 to 6.0, with 4.0 being preferred in this embodiment; the FeO mass fraction in the slag can be within the range of 15% to 30%, with 22.43% being preferred in this embodiment.

[0036] Example 3 This embodiment takes the converter smelting process of HRB400E steel as an example. The process flow is: 120t BOF + Ar station + LF + CC. The specific steps are as follows: Step 1: Add 11.61t of DRI and 127t of semi-steel sequentially to the converter. The amount of DRI added can be ≤90kg / t, and 90kg / t is preferred in this embodiment. The flow rate of top-blown oxygen during the blowing stage can be 26000Nm³ / h~28000Nm³ / h, and 27000Nm³ / h is preferred in this embodiment. The composition of the added semi-steel can be within the range of C: 2.90%~3.70%, Si: 0.02%~0.06%, Mn: 0.02%~0.07%, P: 0.08%~0.16%, S: 0.02%~0.15%, V: 0.02%~0.06%, and is preferred in this embodiment: C: 3.02%, Si: 0.025%, Mn: 0.028%, P: 0.111%, S: 0.148%, V: 0.047%, with the remainder being Fe.

[0037] Step 2: When starting the oxygen lance, the position of the lance can be within the range of 1900mm~2000mm, and in this embodiment, 1977mm is preferred; Step 3: Blowing for ≤4 minutes, lowering the lance position to within the range of 1600mm~1800mm, preferably 1742mm in this embodiment. Add the first batch of slag-forming materials, including 500kg of dolomite and 950kg of lime. Continue lowering the lance position, which can be within the range of 1500mm~1700mm, preferably 1642mm in this embodiment. Add the second batch of slag-forming materials, including 200kg of magnesium balls, 600kg of lime, and 830kg of dolomite. Subsequently, the lance position can be further dynamically adjusted to within the range of 1200mm~1400mm, preferably 1367mm in this embodiment. The total amount of dolomite added can be within the range of 13kg / t~18kg / t, and the total amount of lime added can be within the range of 16kg / t~22kg / t; preferably 1830kg of dolomite and 2300kg of lime in this embodiment.

[0038] Step 4: Blow for 4-8 minutes, raising the gun position to a range of 1750mm-1850mm. In this embodiment, 1755mm is preferred. Add the third batch of slag-forming materials, including 500kg of dolomite and 750kg of lime.

[0039] Step 5: Blow for 8-12 minutes, then lower the gun position again to within the range of 1300mm-1400mm. In this embodiment, 1360mm is preferred, and maintain this gun position until the end of the blowing process.

[0040] Following the above steps, the HRB400E smelting process in the converter is stable. The final temperature of the converter smelting can be in the range of 1560℃ to 1660℃, with 1577℃ being preferred in this embodiment; the slag basicity can be in the range of 3.0 to 6.0, with 3.80 being preferred in this embodiment; the FeO mass fraction in the slag can be in the range of 15% to 30%, with 23.65% being preferred in this embodiment.

[0041] In the above embodiments, the splashing situation was observed and recorded visually at the furnace mouth throughout the blowing process; the final temperature was obtained by sub-lance temperature measurement, and the slag basicity and FeO mass fraction in the slag were obtained by slag sample analysis. The main process parameters and smelting results of Examples 1-3 are summarized in Table 1.

[0042] Table 1

[0043] As shown in Table 1, the DRI addition amounts in Examples 1-3 were 62 kg / t, 80 kg / t, and 90 kg / t, respectively, covering the low, medium, and high levels of DRI addition in this invention. No significant splashing occurred during the smelting process in any of the three examples, and the process was stable. This indicates that the invention, through the coupling of the lance position trend of "high lance position at the start of blowing → gradually lowering the lance in the early stage of blowing → raising the lance in the middle stage of blowing → lowering the lance again in the later stage of blowing and maintaining it until the end of blowing" with the addition of slag-forming material in three batches, has a stable inhibitory effect on foamy slag splashing in DRI furnaces. Meanwhile, the converter endpoint temperatures in Examples 1-3 were 1660℃, 1639℃, and 1577℃, respectively; the slag basicity was 5.6, 4.0, and 3.80, respectively; and the FeO mass fraction in the endpoint slag was 19.23%, 22.43%, and 23.65%, respectively, all within the target control range. This indicates that the invention, while inhibiting splashing, maintains stable endpoint control, and keeps the slag basicity and oxidizing properties within a suitable range, providing favorable conditions for dephosphorization during the smelting process.

[0044] The embodiments described above are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; any equivalent substitutions made by those skilled in the art within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for suppressing splashing during the DRI process in converter smelting, characterized in that, The method includes the following steps: Step 1: First, add DRI into the converter, then add semi-steel, and then lower the oxygen lance for top-blown smelting. Step 2: Start the blowing process. The oxygen lance position at the start of the blowing process is the highest position of the lance throughout the entire blowing process. Step 3: In the early stage of blowing, the slag-forming material is added in batches, and the oxygen lance position is gradually lowered; Step 4: In the middle stage of refining, raise the oxygen lance position to a higher level than the lance position at the end of the early stage of refining; Step 5: In the later stage of the forging process, lower the gun position again to a level comparable to the gun position at the end of the early stage of the forging process, and maintain this gun position until the end of the forging process.

2. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, In step two, the oxygen lance position during the initial blowing is controlled between 1850mm and 2050mm; in step three, the oxygen lance position is first lowered to between 1500mm and 1850mm, and then dynamically adjusted to between 1150mm and 1450mm; in step four, the oxygen lance position is raised to between 1700mm and 1900mm; in step five, the oxygen lance position is lowered to between 1250mm and 1450mm and maintained at this position until the blowing end point.

3. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, The semi-steel composition in step one is: C: 2.90% to 3.70%, Si: 0.02% to 0.06%, Mn: 0.02% to 0.07%, P: 0.08% to 0.16%, S: 0.02% to 0.15%, V: 0.02% to 0.06%, with the remainder being Fe.

4. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, The amount of DRI added in step one is ≤90kg / t.

5. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, The flow rate of top-blown oxygen mentioned in step one is 26,000 Nm³ / h to 28,000 Nm³ / h during the blowing stage.

6. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, The slag-forming material consists of lime, dolomite, and magnesium spheres, and is added in three batches: In the first batch, when the gun position was lowered to 1600mm to 1800mm in the early stage of smelting, dolomite and lime were added; In the second batch, when the gun position is lowered to 1500mm to 1700mm in the early stage of blowing, magnesium balls, dolomite and lime are added; In the third batch, when the gun position is raised to 1750mm to 1850mm during the mid-stage of the blowing process, the remaining dolomite and lime are added.

7. The method for suppressing splashing during the DRI process in converter smelting according to claim 6, characterized in that, The total amount of dolomite added is 13 kg / t to 18 kg / t, and the total amount of lime added is 16 kg / t to 22 kg / t.

8. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, The method is applied to the process route of BOF+Ar station+LF+CC or BOF+Ar station+CC.

9. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, The final temperature of the converter smelting is controlled at 1560℃ to 1660℃, the slag basicity is controlled at 3.0 to 6.0, and the FeO mass fraction in the slag is controlled at 15% to 30%.

10. The method for suppressing splashing during the DRI process in converter smelting according to claim 1, characterized in that, The early stage of refining is from the start of refining to 4 minutes of refining, the middle stage of refining is from 4 minutes to 8 minutes of refining, and the late stage of refining is from 8 minutes of refining to the end of refining.

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