High-silicon high-manganese molten iron converter double-slag automatic control smelting method

Abstract

This invention belongs to the field of iron and steel smelting technology, specifically disclosing an automatic control smelting method for high-silicon and high-manganese molten iron converters with dual slag. The method includes: S1: preparing molten iron with the following conditions: temperature 1220-1400℃, silicon content 0.70%-0.99%, manganese content ≥0.60%, and the molten iron ratio controlled below 74%; S2: using a five-hole oxygen lance for blowing, with the lance lowered in stages during the initial blowing and ignition phases and the rapid oxidation period of silicon and manganese; S3: calculating the timing for slag removal based on the silicon content of the molten iron entering the furnace, and performing slag removal when the preset oxygen consumption is reached, discharging the highly oxidizing slag generated under high-silicon and high-manganese conditions; S4: a second lance lowering, using a phased mode for subsequent smelting; S5: throughout the blowing process, slag-forming raw materials lime, magnesium balls, and sintered ore are added in batches according to set nodes. This method achieves precise control of the slag removal timing through quantitative calculation, stabilizing the residual silicon content within the target range.

Description

Technical Field

[0001] This invention relates to the field of iron and steel smelting technology, specifically to an automatic control smelting method for dual-slag in a high-silicon, high-manganese molten iron converter. Background Technology

[0002] In the process of the steel industry moving towards high-quality development, blast furnaces, in order to further reduce production costs, have successively produced molten iron with fluctuating compositions, such as medium- and high-silicon and high-manganese. The steelmaking process needs to handle this type of molten iron to maximize efficiency. As the core raw material for converter steelmaking, the silicon and manganese content of molten iron directly affects the heat balance, slag-forming efficiency, and steel quality in the smelting process. Although high-silicon and high-manganese molten iron can provide sufficient smelting heat, it also brings problems such as large slag volume, violent reactions, and difficulty in process control, placing higher demands on the stability and controllability of converter smelting.

[0003] Existing technologies have been explored to some extent for optimizing the smelting of high-silicon or high-manganese molten iron. For example, methods such as low-lance position enhanced stirring and staged slag formation using a dual-slag method can alleviate problems such as large slag volume and rapid temperature rise in high-silicon molten iron, and slag overflow in high-manganese molten iron, ensuring smooth smelting of molten iron with abnormal single compositions. However, when molten iron exhibits both high silicon and high manganese characteristics, existing single control methods are insufficient to address the combined effects of silicon and manganese oxidation reactions. This can easily lead to risks such as increased slag overflow in the early stages, decreased dephosphorization capacity, metal splashing in the middle stages, and slag drying and sticking to the lance, failing to meet the actual needs of Baosteel Company's steelmaking plant for the efficient and stable smelting of this type of molten iron.

[0004] Currently, there are still significant limitations in the smelting methods for molten iron with "high silicon and high manganese" composite characteristics. Traditional experience-based steelmaking methods are difficult to accurately match complex reaction processes, while existing automatic control schemes are mostly designed for molten iron with single abnormal components. They lack targeted control over the combined effects of high silicon and high manganese characteristics, resulting in frequent splashing and slag overflow during the smelting process, high oxygen consumption, and insufficient precision in endpoint control. This makes it impossible to achieve efficient and smooth production of this type of molten iron, which restricts enterprises from reducing costs, increasing efficiency, and improving product quality. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic control smelting method for high-silicon and high-manganese molten iron converters with dual slags, in order to solve the problems that traditional experience-based steelmaking methods and existing automatic control schemes cannot accurately match complex reaction processes, resulting in frequent splashing and slag overflow during the smelting process, high oxygen consumption, and insufficient precision in endpoint control.

[0006] To achieve the above objectives, the basic solution provided by this invention is: an automatic control smelting method for dual-slag in a high-silicon, high-manganese molten iron converter, comprising the following steps: S1: Prepare molten iron. The conditions for molten iron are: temperature between 1220-1400℃, silicon content between 0.70%-0.99%, manganese content ≥0.60%, and the molten iron ratio controlled below 74%. S2: Five-hole oxygen lances are used for blowing. During the initial blowing and ignition stage and the rapid oxidation period of ferrosilicon and manganese, high oxygen supply intensity is used in combination with staged lance reduction to promote rapid slag formation in the early stage. S3: Calculate the timing of slag removal based on the silicon content of the molten iron entering the furnace. When the blowing reaches the preset oxygen consumption, perform the slag removal operation to discharge the highly oxidizing slag generated under high silicon and high manganese conditions out of the furnace. S4: After the slag is removed, the gun is lowered a second time. The subsequent smelting is carried out in a phased mode of "low oxygen supply intensity - gradually increasing intensity - step-by-step gun lowering" until the blowing end point. S5: Throughout the blowing process, the slag-forming raw materials, lime, magnesium balls, and sinter, are added in batches according to the set nodes.

[0007] The working principle of this invention is as follows: Addressing the characteristics of high-silicon, high-manganese molten iron with intense silicon and manganese oxidation and large slag volume in the early stages, this invention mitigates the risk of slag overflow by controlling the iron-to-metal ratio to balance heat release from the source. In the early stages of blowing, a high oxygen supply intensity is used in conjunction with phased lance lowering to accelerate slag formation. Based on a model corresponding to silicon content and oxygen consumption, the timing of slag removal is precisely calculated to discharge highly oxidizing slag from the furnace. After the second lance lowering, a phased mode of "low oxygen supply intensity for arc initiation - gradually increasing intensity - step-by-step lance lowering" is adopted, along with precise batch feeding, to achieve stable control of the secondary blowing process and accurate endpoint targeting.

[0008] The beneficial effects of this invention are as follows: This method achieves precise control of the slag dumping timing through quantitative calculation, solving the problem of reliance on experience in traditional dual-slag operation and stabilizing the residual silicon content within the target range. The staged control mode of secondary blowing effectively avoids splashing and re-drying, improving smelting stability. Precise batch feeding ensures dephosphorization efficiency while reducing auxiliary material consumption, upgrading the dual-slag process to a data-driven automatic control mode, significantly improving the smelting safety and economy under complex high-silicon and high-manganese molten iron conditions.

[0009] Option 2, which is the preferred option of the basic option, involves the following specific control method for rapid slag formation in the early stage of step S2: When starting oxygenation, maintain a concentration between 0% and 3%, lower the oxygen lance to 1800mm above the liquid surface, and control the oxygen supply intensity at 3.2m. 3 / t·h; When the oxygen content reaches 8%, the oxygen lance is lowered to 1600mm, and 1000kg of sinter is added simultaneously, maintaining the oxygen supply intensity at 3.2m. 3 / t·h; Oxygen levels should be maintained between 8% and 33%, with the oxygen supply point held at 1600mm and the oxygen supply intensity at 3.2m. 3The constant parameter operation of / t·h promotes slag foaming.

[0010] By using a phased lance reduction operation combined with constant oxygen supply intensity in the early stage, the oxidation of ferrosilicon and manganese into slag is accelerated while the sinter is cooled down, which achieves rapid generation and stable foaming of slag in the early stage, laying a stable molten pool foundation for the subsequent double slag dumping process.

[0011] Option 3, which is the preferred option of Option 2, is based on the following calculation for the timing of slag removal in step S3: establishing a model corresponding to the silicon content and oxygen consumption in molten iron, ensuring that the residual silicon content in the molten iron is controlled at around 0.3% after slag removal, the slag removal angle is ≤83°, and the slag discharge angle is controlled at 76°, as detailed below: A silicon content of 0.7% corresponds to an oxygen consumption of 1272 m³. 3 A silicon content of 0.75% corresponds to an oxygen consumption of 1359 m³ / h. 3 A silicon content of 0.8% corresponds to an oxygen consumption of 1443 m³. 3 A silicon content of 0.85% corresponds to an oxygen consumption of 1521 m³. 3 A silicon content of 0.9% corresponds to an oxygen consumption of 1595 m³ / h. 3 A silicon content of 0.95% corresponds to an oxygen consumption of 1665 m³ / h. 3 A silicon content of 0.99% corresponds to an oxygen consumption of 1718 m³. 3 .

[0012] By establishing a quantitative correlation model between silicon content and oxygen consumption in molten iron and coordinating precise angle control, the timing of double slag dumping is transformed from experience-based judgment to data-driven, ensuring that the residual silicon content is stably controlled at around 0.3%. This maximizes the removal of highly oxidizing slag generated under high silicon and high manganese conditions, while creating stable molten pool conditions for secondary lance blowing.

[0013] Option 4, which is the preferred option of Option 3, includes the following three parts in the smelting control mode after the second firing in step S4: Stable transition period: oxygen supply rate 33%-35%, gun position maintained at 1600mm, oxygen supply intensity reduced to 2.9m. 3 / t·h; During the recovery period: oxygen level reaches 35%-38%, the nozzle position is lowered to 1450mm, and the oxygen supply intensity is increased to 3.08m. 3 / t·h; During normal smelting: oxygen step 38%-50%, gradually lower the lance position to 1250mm at a rate of 100mm decrease for every 3%-5% increase in oxygen step, restoring the oxygen supply intensity to 3.2m. 3 / t·h.

[0014] The phased progressive control strategy of "smooth transition at low oxygen supply intensity - medium intensity activity recovery - stepwise lance lowering to enhance stirring" after the second lance lowering effectively avoids splashing and back-drying caused by a sudden reduction in slag volume after the double slag process, and achieves a smooth connection and rapid recovery of the molten pool reaction.

[0015] Option 5, which is the preferred option of Option 4, involves adding materials in batches in step S5 as follows: Initial slag formation: When the oxygen content is 6%, add 30% of the total amount of lime to ensure that the initial alkalinity is controlled at around 0.8; Secondary slag formation: After the slag is poured out, the remaining lime is calculated and replenished according to the residual silicon content so that the slag alkalinity during the secondary smelting period meets the dephosphorization requirements.

[0016] The oxygen step precisely controls the initial alkalinity at 6% and uses a batch-based synergistic feeding mode that dynamically replenishes lime based on residual silicon after slag dumping. This ensures the alkalinity required for dephosphorization at each stage while avoiding slag waste, achieving a dual optimization of slag-making costs and smelting quality.

[0017] Option 6, which is the preferred option of Option 5, involves implementing the following operations during the endpoint control phase: When the oxygen consumption is 800m from the finish line 3 At this time, raise the oxygen lance to 1300mm to concentrate ferrous oxide to help with slag formation; When the oxygen consumption is 500m away from the finish line 3 At that time, the oxygen lance was lowered to 1000mm, while the oxygen supply intensity was increased to 3.45m. 3 / t·h, to enhance final mixing and final residue adjustment.

[0018] The timing sequence of "lifting the lance to melt the slag first, then lowering the lance to stir" in the final stage ensures that the slag is fully melted to cover the surface of the molten steel while strengthening the stirring of the molten pool, effectively solving the dual problems of difficult decarburization at the final stage and poor final slag adjustment.

[0019] Option 7, an optimal choice from Option 6, maintains the molten pool temperature between 1580℃ and 1680℃ throughout the blowing process, and controls the carbon content of the molten steel at the final stage between 0.06% and 0.12%. By controlling the molten pool temperature and the final carbon content, the thermodynamic conditions for dephosphorization and decarburization reactions are synergistically optimized with the endpoint hit, ensuring the purity of the molten steel while avoiding over-burning of the furnace lining, thus significantly improving the stability of smelting quality.

[0020] Option 8, an optimal choice of Option 7, involves a six-hole annular arrangement of bottom-blowing elements. The working gas is switched between nitrogen and argon depending on the smelting stage. By combining the six-hole annular arrangement with a segmented nitrogen-argon switching bottom-blowing mode, the stirring intensity requirements of each smelting stage are dynamically matched. In the early stage, nitrogen is used to enhance the uniformity of the molten pool and reduce production costs, while in the later stage, switching to argon avoids nitrogen addition and improves the purity of the molten steel. Attached Figure Description

[0021] Figure 1 This is a blowing lance position diagram of an automatic control smelting method for dual slag in a high-silicon and high-manganese molten iron converter according to the present invention. Detailed Implementation

[0022] The present invention will be further described in detail below through specific embodiments: like Figure 1 The following is an example of an automated control smelting method for high-silicon, high-manganese molten iron converter using dual slag, comprising the following steps: S1: Prepare molten iron. The conditions for molten iron are: temperature between 1220-1400℃, silicon content between 0.70%-0.99%, manganese content ≥0.60%, and the molten iron ratio controlled below 74%. S2: Five-hole oxygen lances are used for blowing. During the initial blowing and ignition stage and the rapid oxidation period of ferrosilicon and manganese, high oxygen supply intensity is combined with staged lance lowering to promote rapid slag formation in the early stage. The specific control method for rapid slag formation in the early stage is as follows: When starting oxygenation, maintain a concentration between 0% and 3%, lower the oxygen lance to 1800mm above the liquid surface, and control the oxygen supply intensity at 3.2m. 3 / t·h; When the oxygen content reaches 8%, the oxygen lance is lowered to 1600mm, and 1000kg of sinter is added simultaneously, maintaining the oxygen supply intensity at 3.2m. 3 / t·h; Oxygen levels should be maintained between 8% and 33%, with the oxygen supply point held at 1600mm and the oxygen supply intensity at 3.2m. 3 Constant parameter operation at / t·h promotes slag foaming; S3: Calculate the slag removal timing based on the silicon content of the molten iron. When the pre-set oxygen consumption is reached during blowing, perform the slag removal operation to discharge the highly oxidizing slag generated under high silicon and high manganese conditions. The calculation basis for the slag removal timing is: establish a corresponding model between the silicon content of molten iron and the oxygen consumption to ensure that the residual silicon content in the molten iron after slag removal is controlled at around 0.3%, the slag removal angle is ≤83°, and the slag discharge angle is controlled at 76°, as detailed below: A silicon content of 0.7% corresponds to an oxygen consumption of 1272 m³. 3 A silicon content of 0.75% corresponds to an oxygen consumption of 1359 m³ / h. 3 A silicon content of 0.8% corresponds to an oxygen consumption of 1443 m³. 3 A silicon content of 0.85% corresponds to an oxygen consumption of 1521 m³. 3 A silicon content of 0.9% corresponds to an oxygen consumption of 1595 m³ / h. 3 A silicon content of 0.95% corresponds to an oxygen consumption of 1665 m³ / h. 3 A silicon content of 0.99% corresponds to an oxygen consumption of 1718 m³. 3 ; S4: After the slag removal is completed, the lance is lowered a second time. The subsequent smelting is carried out in a phased mode of "low oxygen supply intensity - gradually increasing intensity - step-by-step lance lowering" until the blowing end. The smelting control mode after the second lance lowering includes the following three parts: Stable transition period: oxygen supply rate 33%-35%, gun position maintained at 1600mm, oxygen supply intensity reduced to 2.9m. 3 / t·h; During the recovery period: oxygen level reaches 35%-38%, the nozzle position is lowered to 1450mm, and the oxygen supply intensity is increased to 3.08m. 3 / t·h; During normal smelting: oxygen step 38%-50%, gradually lower the lance position to 1250mm at a rate of 100mm decrease for every 3%-5% increase in oxygen step, restoring the oxygen supply intensity to 3.2m. 3 / t·h; S5: Throughout the blowing process, the slag-forming raw materials, lime, magnesium pellets, and sinter, are added in batches according to the set milestones. The specific method for batch feeding is as follows: Initial slag formation: When the oxygen content is 6%, add 30% of the total amount of lime to ensure that the initial alkalinity is controlled at around 0.8; Secondary slag formation: After the slag is poured out, the remaining lime is calculated and replenished according to the residual silicon content so that the slag alkalinity during the secondary smelting period meets the dephosphorization requirements.

[0023] In summary, the molten pool temperature is controlled at 1580℃-1680℃ throughout the blowing process, and the carbon content of the molten steel at the final stage is controlled at 0.06%-0.12%. The bottom blowing elements are arranged in a six-hole ring, and the working gas is switched between nitrogen and argon according to the smelting stage. The following operations are implemented in the final control stage: When the oxygen consumption is 800m from the finish line 3 At this point, raise the oxygen lance to 1300mm to concentrate ferrous oxide and aid in slag formation; when the oxygen consumption is 500m from the endpoint... 3 At that time, the oxygen lance was lowered to 1000mm, while the oxygen supply intensity was increased to 3.45m. 3 / t·h, to enhance final mixing and final residue adjustment.

[0024] The implementation method of this embodiment is as follows: The converter used in this embodiment has a nominal capacity of 120 tons, the oxygen lance adopts a five-hole nozzle structure, the oxygen lance diameter is 273mm, the bottom blowing element is arranged in a six-hole ring, and the working gas is switched between nitrogen and argon according to the smelting stage.

[0025] Before smelting, the composition and temperature of the molten iron entering the furnace are tested to ensure that the conditions meet the process parameters set in this invention: the molten iron temperature is controlled within the range of 1220-1400℃, the silicon content is 0.70%-0.99%, and the manganese content is ≥0.60%. In this furnace, the molten iron temperature is 1260℃, the silicon content is 0.85%, and the manganese content is 0.92%. Based on the molten iron conditions, the molten iron ratio is controlled below 74%. In this furnace, the molten iron ratio is controlled at 72%, meaning the molten iron charge is 86.4 tons, and the scrap steel charge is 33.6 tons. High-quality crushed scrap and self-produced cut ends are used to ensure a stable charging process.

[0026] The blowing process is divided into multiple control stages according to the oxygen step. The oxygen lance position, oxygen supply intensity, and bottom blowing flow rate are dynamically adjusted according to preset rules. The oxygen step-lance position correspondence table shown in the figure is the core control basis of this embodiment. The specific implementation process is as follows: (a) The initial rapid slag-forming stage, during which the oxygen content ranges from 0% to 33%: When the oxygen level reaches 0%, the oxygen lance begins to descend. Within the oxygen level range of 0%-3%, the oxygen lance is lowered to a position 1800mm above the molten metal surface, while the oxygen supply intensity is set to 3.2m. 3 / t·h。 The operator observed that the oxygen lance ignited successfully on the first attempt, and the flame at the furnace mouth was stable.

[0027] When the oxygen level reaches 6%, the first batch of slag is added. According to the feeding information corresponding to 6% oxygen level in the image, 30% of the total lime (approximately 2.1 tons) is added at this time to ensure that the slag basicity is controlled at around 0.8 in the early stage, creating conditions for the subsequent rapid oxidation of ferrosilicon and manganese.

[0028] When the oxygen level reaches 8%, the oxygen lance position is lowered to 1600mm from the molten metal surface, while the oxygen supply intensity remains at 3.2m. 3 / t·h, and at the same time, 1000kg of sintered ore is added to balance the temperature of the molten pool and suppress the excessive oxidation reaction of silicon and manganese in the early stage. The picture shows that from the oxygen step of 8% to the oxygen step of 20%, the lance position is stable at around 1600mm, specifically 1600mm at oxygen step of 8%, 1600mm at oxygen step of 15%, and returns to normal after a brief change due to lance lifting operation at oxygen step of 20%.

[0029] Maintain an oxygen supply level of 1600mm and an oxygen supply intensity of 3.2m within the oxygen step range of 8%-33%. 3 The constant parameter operation ( / t·h) promotes slag foaming. Operators observed that the slag gradually became more active, and the slag layer thickness increased, preparing for subsequent double-slag dumping.

[0030] When the oxygen level reaches 20%, the image shows a brief lance lifting operation (lance position 6000mm). This is actually a preparatory action before slag dumping, and the operator prepares to dump the slag according to the system prompts.

[0031] (ii) Precision slag removal stage, during which the oxygen content ranges from 20% to 33%: Based on the silicon content of 0.85% in this batch of molten iron, and referring to the model corresponding to silicon content and oxygen consumption, the oxygen consumption at the slag removal timing is determined to be 1521 m³. 3 The system calculates the cumulative oxygen consumption in real time, and automatically prompts for slag removal when the preset value is reached.

[0032] Before the slag removal operation, the oxygen level was between 20% and 33%, and the oxygen supply intensity was maintained at 3.2 m. 3 / t·h, the operators controlled the slag dumping angle to be ≤83° as required. In this furnace, the slag dumping angle was controlled at 80°, and the slag discharge angle was controlled at 76°, so as to smoothly discharge the high oxidizing slag generated in the early stage out of the furnace. After dumping the slag, the residual silicon content was tested to be 0.31%, which meets the target control requirement (target requirement is 0.3%±0.01%).

[0033] (III) The smooth transition period after the second injection, during which the oxygen intake range is 33%-35%: After slag removal, the amount of slag on the molten steel surface decreases significantly. At this point, automatic smelting is initiated a second time using the lance. During the oxygen step of 33%-35%, a stable transition period begins: the lance position is maintained at 1600mm, and the oxygen supply intensity is reduced to 2.9m. 3 / t·h. During this stage, the operators observed that the flame was more stable than before, with no obvious splashing.

[0034] (iv) Activity recovery period, during which the oxygen step ratio is between 35% and 38%: When the oxygen supply reaches 35%, the activity recovery period begins: the oxygen supply position is lowered to 1450mm, and the oxygen supply intensity is increased to 3.08m. 3 At this point, the molten pool reaction gradually becomes more active, and the slag begins to reform. Based on the flame condition, the operators determine that the secondary blowing process has proceeded smoothly.

[0035] (v) During the normal smelting period, the oxygen content ranges from 38% to 50%. When the oxygen content reaches 38%, the normal smelting period begins, and the oxygen supply intensity recovers to 3.2 m. 3 For a slag activity level of / t·h, from 38% to 50% oxygen step rate, the lance position was gradually lowered at a rate of 100mm decrease for every 3%-5% increase in oxygen step rate. The image shows the specific control points as follows: 1800mm from the molten metal surface at oxygen step rate of 38%, 40%, 45%, and 50%. Operators observed moderate slag activity and no back-drying or splashing phenomena.

[0036] Meanwhile, during the secondary slag-making stage, the required amount of lime to be added is calculated based on the residual silicon content of 0.31% after slag pouring, and the remaining lime (70% of the total lime, about 4.9 tons) is replenished to ensure that the slag alkalinity during the secondary smelting period meets the dephosphorization requirements.

[0037] (vi) Main blowing and final adjustment stage, during which the oxygen step ratio is between 50% and 100%: Within the oxygen supply range of 50%-95%, continue to control the nozzle position according to the preset parameters. At 60% oxygen supply, the nozzle position should be 1800mm from the molten metal surface; at 70% oxygen supply, the position should be 1800mm from the molten metal surface; at 80% oxygen supply, the position should be 1800mm from the molten metal surface; at 95% oxygen supply, the nozzle position should be slightly adjusted, maintaining a distance of 1800mm from the molten metal surface. Maintain an oxygen supply intensity of 3.2m. 3 / t·h, the bottom blowing gas is switched to argon in the later stage to avoid nitrogen addition to the molten steel.

[0038] When the oxygen consumption is 800m from the finish line 3 At this point, corresponding to an oxygen step of approximately 90%, the oxygen lance was raised to 1300mm to concentrate ferrous oxide and aid in slag formation. Operators observed improved slag fluidity and good slag formation results.

[0039] When the oxygen consumption is 500m away from the finish line 3 At this point, corresponding to an oxygen supply level of approximately 95%-96%, the oxygen lance is lowered to 1000mm, while the oxygen supply intensity is increased to 3.45m. 3 / t·h, to enhance endpoint stirring and final slag adjustment. At this point, the carbon-oxygen reaction enters its final stage, and low gun position with high oxygen supply intensity helps to promote endpoint decarbonization.

[0040] The blowing process ended when the oxygen content reached 100%. Testing showed the final steel temperature was 1645℃, within the target range of 1580℃-1680℃; the final carbon content was 0.09%, meeting the control requirement of 0.06%-0.12%. The slag basicity was moderate, slag formation was good, and the steel composition and temperature met the targets.

[0041] This embodiment strictly follows the preset control mode throughout the entire process. The key parameters are shown in the table below: Table 1 Key Parameter Description Table This embodiment addresses the complex hot metal conditions of high silicon (0.70%-0.99%) and high manganese (≥0.60%). Employing a 72% hot metal ratio and a five-hole oxygen lance, it achieves precise slag removal by establishing a model corresponding to silicon content and oxygen consumption. Combined with a phased control mode after the second lance lowering—a smooth transition from low oxygen supply intensity to medium-intensity activity recovery and then a stepped lance lowering for enhanced stirring—automatic smelting using the dual-slag method was successfully realized. No abnormal conditions such as early-stage slag overflow or mid-stage splashing occurred throughout the process, and the final composition and temperature accurately met the target. Compared to the conventional dual-slag method, this method transforms slag removal timing from experience-based judgment to data-driven analysis, significantly improving smelting stability and reducing auxiliary material consumption. It provides a reliable technical solution for automated steelmaking in converters under complex hot metal conditions of high silicon and high manganese.

[0042] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An automatic control smelting method for dual-slag in a high-silicon, high-manganese molten iron converter, characterized in that, Includes the following steps: S1: Prepare molten iron. The conditions for molten iron are: temperature between 1220-1400℃, silicon content between 0.70%-0.99%, manganese content ≥0.60%, and the molten iron ratio controlled below 74%. S2: Five-hole oxygen lances are used for blowing. During the initial blowing and ignition stage and the rapid oxidation period of ferrosilicon and manganese, high oxygen supply intensity is used in combination with staged lance reduction to promote rapid slag formation in the early stage. S3: Calculate the timing of slag removal based on the silicon content of the molten iron entering the furnace. When the blowing reaches the preset oxygen consumption, perform the slag removal operation to discharge the highly oxidizing slag generated under high silicon and high manganese conditions out of the furnace. S4: After the slag is removed, the gun is lowered a second time. The subsequent smelting is carried out in a phased mode of "low oxygen supply intensity - gradually increasing intensity - step-by-step gun lowering" until the blowing end point. S5: Throughout the blowing process, the slag-forming raw materials, lime, magnesium balls, and sinter, are added in batches according to the set nodes.

2. The automatic control smelting method for dual-slag in a high-silicon, high-manganese hot metal converter according to claim 1, characterized in that, The specific control method for rapid slag formation in the early stage of step S2 is as follows: The oxygen blowing step is in the interval of 0-3%, and the oxygen lance is lowered to 1800mm from the liquid surface, and the oxygen supply intensity is controlled at 3.2m 3 / t·h; When the oxygen level reaches 8%, the oxygen lance is lowered to 1600 mm, while 1000 kg of sinter is added, and the oxygen supply intensity is maintained at 3.2 m 3 / t·h; Oxygen step reached 8-33% range, maintain gun position 1600 mm and oxygen intensity 3.2 m 3 Constant parameter operation, promote slag foaming.

3. The automatic control smelting method for dual-slag in a high-silicon, high-manganese hot metal converter according to claim 2, characterized in that, The calculation basis for the timing of slag removal in step S3 is as follows: A corresponding model of silicon content and oxygen consumption in molten iron is established to ensure that the residual silicon content in the molten iron after slag removal is controlled at 0.3% ± 0.02%, the slag removal angle is ≤ 83°, and the slag discharge angle is controlled at 76°, as detailed below: A silicon content of 0.7% corresponds to an oxygen consumption of 1272 m³. 3 A silicon content of 0.75% corresponds to an oxygen consumption of 1359 m³ / h. 3 A silicon content of 0.8% corresponds to an oxygen consumption of 1443 m³. 3 A silicon content of 0.85% corresponds to an oxygen consumption of 1521 m³. 3 A silicon content of 0.9% corresponds to an oxygen consumption of 1595 m³ / h. 3 A silicon content of 0.95% corresponds to an oxygen consumption of 1665 m³ / h. 3 A silicon content of 0.99% corresponds to an oxygen consumption of 1718 m³. 3 .

4. The automatic control smelting method for dual-slag in a high-silicon, high-manganese hot metal converter according to claim 3, characterized in that, The smelting control mode after the second firing in step S4 includes the following three parts: Stable transition period: oxygen supply rate 33%-35%, gun position maintained at 1600mm, oxygen supply intensity reduced to 2.9m. 3 / t·h; During the recovery period: oxygen level reaches 35%-38%, the nozzle position is lowered to 1450mm, and the oxygen supply intensity is increased to 3.08m. 3 / t·h; During normal smelting: oxygen step 38%-50%, gradually lower the lance position to 1250mm at a rate of 100mm decrease for every 3%-5% increase in oxygen step, restoring the oxygen supply intensity to 3.2m. 3 / t·h.

5. The automatic control smelting method for dual-slag in a high-silicon, high-manganese hot metal converter according to claim 4, characterized in that, The specific method for batch feeding in step S5 is as follows: Initial slag formation: When the oxygen step is 6%, add 30% of the total amount of lime to ensure that the initial alkalinity is controlled at 0.8±0.05; Secondary slag formation: After the slag is poured out, the remaining lime is calculated and replenished according to the residual silicon content so that the slag alkalinity during the secondary smelting period meets the dephosphorization requirements.

6. The automatic control smelting method for dual-slag in a high-silicon, high-manganese hot metal converter according to claim 5, characterized in that, The following actions will be performed during the endpoint control phase: When the oxygen consumption is 800m from the finish line 3 At this time, raise the oxygen lance to 1300mm to concentrate ferrous oxide to help with slag formation; When the oxygen consumption is 500m away from the finish line 3 At that time, the oxygen lance was lowered to 1000mm, while the oxygen supply intensity was increased to 3.45m. 3 / t·h, to enhance final mixing and final residue adjustment.

7. The automatic control smelting method for dual-slag in a high-silicon, high-manganese hot metal converter according to claim 6, characterized in that, The molten pool temperature is controlled at 1580℃-1680℃ throughout the blowing process, and the carbon content of the final molten steel is controlled at 0.06%-0.12%.

8. The automatic control smelting method for dual-slag in a high-silicon, high-manganese molten iron converter according to claim 7, characterized in that, The bottom blowing elements are arranged in a six-hole ring, and the working gas is switched between nitrogen and argon according to the smelting stage.

Images