CN108060288B - Pre-deoxidation method and device for blowing carbon powder into converter steel tapping hole - Google Patents
Pre-deoxidation method and device for blowing carbon powder into converter steel tapping hole Download PDFInfo
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- CN108060288B CN108060288B CN201810038548.3A CN201810038548A CN108060288B CN 108060288 B CN108060288 B CN 108060288B CN 201810038548 A CN201810038548 A CN 201810038548A CN 108060288 B CN108060288 B CN 108060288B
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- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
- C21C7/0043—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material into the falling stream of molten metal
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Abstract
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a pre-deoxidation method and a pre-deoxidation device for blowing carbon powder into a converter steel tapping hole. A plurality of groups of carbon powder spray pipes are arranged in a tubular refractory material of a steel tapping hole of the converter, carbon powder is sprayed into steel tapping flow through the carbon powder spray pipes in the steel tapping process of the converter, and the carbon powder reacts with dissolved oxygen [ O ] in molten steel to generate CO. Carbon powder is injected into the steel tapping flow through a carbon powder injection pipe in the steel tapping hole to perform deoxidation, the deoxidation product is CO, gaseous CO escapes from the steel tapping flow and is discharged to the atmosphere, impurities cannot be left in molten steel, and the quality of steel cannot be damaged. The carbon powder has larger deoxidation space and strong deoxidation capability, and can remove more than 40 percent of dissolved oxygen in molten steel. Compared with aluminum deoxidation, the adoption of the carbon powder can save about 90% of deoxidation cost; compared with deoxidation by using silicon, the deoxidation cost can be saved by about 80% by using carbon powder.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a pre-deoxidation method and a pre-deoxidation device for blowing carbon powder into a converter steel tapping hole.
Background
The converter has strong capacity of removing C and P, and deep P removing operation is carried out in most converter smelting of steel plants along with the improvement of the quality requirement of customers on steel, the P is controlled to be less than or equal to 0.015% at the smelting end point of the converter, oxygen supply is increased to carry out oxidation dephosphorization for controlling the lower content of phosphorus, and oxygen in molten steel is controlled to be 400-600 ppm, so that the molten steel is seriously oxidized. In order to achieve the effect of deep dephosphorization, a converter generally adopts a method of blowing excessive oxygen, and besides ultra-low carbon steel, carbon in molten steel at the smelting end point of the converter is far less than that in target components of steel.
At present, most steel mills remove dissolved oxygen by adding strong deoxidizers into steel ladles in the tapping process of converters, wherein the deoxidizers are generally substances containing Al, si, mn, ca and Mg and have strong deoxidizing capacity, but Al can be generated after the deoxidizers react with oxygen 2 O 3 、SiO 2 Inclusions such as MnO, caO, mgO, etc., which are harmful to steel, need to be removed through a subsequent argon blowing or refining process, and the production cost is increased by blowing argon and refining for a long time.
And part of steel works add part of carbon powder to the steel ladle for pre-deoxidation in the first 1/2-1/3 period of the converter tapping process, add aluminum strong deoxidizer to the steel ladle for deep deoxidation in the later period of the converter tapping process, and add alloy to adjust the components of molten steel. Although the method can achieve the effect of deoxidizing by replacing part of aluminum deoxidizers with carbon powder in the early stage of the converter tapping process, the aluminum deoxidizers and the alloys with strong deoxidizing capacity are added in the middle and later stages of the converter tapping process, so that the aluminum deoxidizers and the alloys with strong deoxidizing capacity play the main deoxidizing role, and the carbon powder cannot achieve the deoxidizing effect. And because the density of the carbon powder is small, the carbon powder which is not dissolved in the molten steel can float to the surface of the molten steel after being added into the ladle, and the deoxidation kinetic condition is poor.
Disclosure of Invention
In order to solve the problems, the invention provides a pre-deoxidation method and a pre-deoxidation device for blowing carbon powder into a steel tapping hole of a converter.
The pre-deoxidation device for injecting carbon powder in a steel tapping hole of a converter is characterized in that a main channel for injecting carbon powder is arranged in a direction parallel to the steel tapping hole, the main channel for injecting carbon powder is connected with a powder injection system, 2-8 groups of annular carbon powder channels are arranged around the steel tapping hole, all the annular carbon powder channels 3 are connected with the main channel for injecting carbon powder, and 2-8 carbon powder spray pipes embedded in refractory materials of the steel tapping hole are connected to each group of carbon powder channels.
More preferably, the pre-deoxidation device for blowing the carbon powder into the steel tapping hole of the converter further comprises a valve; the main channel for blowing the carbon powder is connected with a powder spraying system through a valve.
More preferably, the pre-deoxidation device for blowing the carbon powder in the steel tapping hole of the converter further comprises a flow meter and/or a pressure gauge; the main channel for blowing the carbon powder is connected with a powder spraying system through a flowmeter and/or a pressure gauge.
More preferably, the pre-deoxidation device for blowing the carbon powder in the steel tapping hole of the converter further comprises a buffer gas tank; the main channel for blowing the carbon powder is connected with a powder spraying system through one or more of a flowmeter, a pressure gauge, a buffer gas tank and/or a valve.
Preferably, the inner diameter of the total channel for blowing the carbon powder is phi 20-30 mm, and the material is steel.
Preferably, the inner diameter of the circular carbon powder channel is phi 10-15 mm, and the material is steel.
Preferably, the carbon powder spray pipe has an inner diameter of phi 4-9 mm and is made of steel.
When the steel tapping hole needs to be replaced, the steel tapping hole provided with the carbon powder spray pipe is arranged on the converter, a total channel exposed outside the steel tapping hole and used for spraying carbon powder and an annular carbon powder channel are wrapped by refractory mortar, and the converter can perform normal smelting operation after the refractory mortar is dried by the waste heat of the converter.
The invention provides a pre-deoxidation method for blowing carbon powder into a converter steel tapping hole, which comprises the following steps: a plurality of groups of carbon powder spray pipes are arranged in a tubular refractory material of a steel tapping hole of the converter, carbon powder is sprayed into steel tapping flow through the carbon powder spray pipes in the steel tapping process of the converter, and the carbon powder reacts with dissolved oxygen [ O ] in molten steel to generate CO.
The reaction of carbon powder and dissolved oxygen [ O ] in molten steel to generate CO is shown as formula (1), and the calculation formula of the reaction equilibrium constant of formula (1) is shown as formula (2).
[C]+[O]→CO ①
K＝a [C] ×a [O] /P CO ②
By examining the handbook of thermodynamics, the equilibrium constant K of equation 1 is 2.3X 10 at 1600 deg.C -3 。
In the actual production process, at the smelting end point of a converter, the content of carbon and oxygen in molten steel is detected through a sublance, the amount of injected carbon powder is determined according to the carbon content in a target component of the molten steel, carbon powder is injected into the molten steel through a carbon powder injection pipe arranged in a tubular refractory material of a steel outlet of the converter for pre-deoxidation, and according to a reaction formula (2), if the carbon content in the target component of the molten steel is 0.1-0.2%, the oxygen in the molten steel can be deoxidized to 115-230 ppm, more than 40% of dissolved oxygen in the molten steel can be removed, so that the consumption of aluminum deoxidizers and the generation amount of deoxidized inclusions can be reduced.
After the smelting of the converter is finished, detecting the carbon content and the oxygen content in molten steel at the smelting end point of the converter by using a sublance, tapping after the components and the temperature of the molten steel are qualified, rocking a converter body of the converter, supplying argon only by a powder spraying system, namely introducing the argon into a main channel, keeping the pressure of the argon in a spray pipe at 2-3 atmospheric pressures, achieving the effect of preventing the molten steel from flowing backwards to a carbon powder spray pipe embedded in a refractory material layer of a tap hole, supplying a mixture of the argon and the carbon powder by the powder spraying system after the molten steel flows, determining the spraying amount of the carbon powder according to the content of [ C ], [ O ] in the molten steel at the smelting end point of the converter and the carbon content in target components of the molten steel, and keeping the pressure of the argon in the spray pipe 4 at 2-3 atmospheric pressures in the process of spraying the carbon powder, so that the carbon powder reacts with dissolved oxygen [ O ] in the molten steel to generate CO.
In the actual production process, because CO is difficult to dissolve in the molten steel, CO generated by carbon-oxygen reaction can float up to the interface of the molten steel and air and can be burnt in a high-temperature environment, and the CO poisoning phenomenon cannot occur.
The carbon powder spray pipe is arranged in a tubular refractory material of a steel-tapping hole of the converter, during the steel tapping process, when molten steel flows through a steel-tapping hole channel, the deoxidation reaction of the carbon powder and [ O ] is generated, the deoxidized molten steel flows into a steel ladle, and the sprayed carbon powder is used for removing dissolved oxygen in the molten steel which flows out of the converter but does not flow into the steel ladle. The molten steel in the converter can not generate deoxidation phenomenon, and the 'rephosphorization phenomenon' that the phosphorus in the slag is transferred to the molten steel can not occur. The aluminum strong deoxidizer and the alloy added into the steel ladle can not influence the deoxidation reaction of the carbon powder, and the carbon powder can continuously exert the deoxidation effect in the whole tapping process.
The reaction product CO escapes from the steel flow in a gas state and is discharged to the atmosphere, so that inclusions cannot be left in the molten steel, and the quality of the steel cannot be damaged.
THE ADVANTAGES OF THE PRESENT INVENTION
1. Carbon powder is injected into the steel tapping flow through a carbon powder injection pipe in the steel tapping hole to deoxidize, the deoxidized product is CO, gaseous CO escapes from the steel tapping flow and is discharged to the atmosphere, impurities cannot be left in molten steel, and the quality of steel cannot be damaged.
2. Except for ultra-low carbon steel, carbon in molten steel at the smelting end point of the converter is far less than that in target components of steel, and carbon powder has a large deoxidation space and strong deoxidation capability and can remove more than 40% of dissolved oxygen in the molten steel.
3. The carbon powder is cheap, and compared with aluminum for deoxidation, the adoption of the carbon powder can save about 90% of the deoxidation cost; compared with deoxidation by using silicon, the deoxidation cost can be saved by about 80% by using carbon powder.
4. The method for deoxidizing by blowing carbon powder into the steel flow through the carbon powder spray pipe in the steel tapping hole is to deoxidize the molten steel which does not flow into the steel ladle, the strong deoxidizer added into the steel ladle does not influence the deoxidizing behavior of the carbon powder, and the carbon powder has the deoxidizing effect in the whole converter steel tapping process; and in the later period of converter tapping, the carbon powder added into the steel ladle has no deoxidation effect, the main deoxidation effect is still an aluminum deoxidizer and an alloy with stronger deoxidation capability, and the method for deoxidizing by blowing the carbon powder into the tapping steel flow through the carbon powder spray pipe in the tapping hole has the effect obviously superior to the method for deoxidizing the carbon powder added into the steel ladle.
Description of the drawings:
FIG. 1 is a schematic view of a carbon powder nozzle arranged on a converter tap hole.
FIG. 2 isbase:Sub>A cross-sectional view of the A-A surface ofbase:Sub>A steel tapping hole ofbase:Sub>A converter afterbase:Sub>A carbon powder nozzle is arranged on the steel tapping hole.
FIG. 3 is a B-B surface cross-sectional view after a carbon powder spray pipe is arranged on a converter steel tapping hole.
Wherein: 1: a steel flow channel within the tap hole; 2: a refractory layer on the tap hole; 3: a circular ring-shaped carbon powder channel arranged around the steel tapping hole; 4: the carbon powder spray pipe is embedded in the steel tapping hole refractory layer; 5: a main passage for supplying carbon powder; 6: a flow meter; 7: a pressure gauge; 8: a buffer gas tank; 9: a valve; 10: powder spraying system.
The specific implementation mode is as follows:
according to the drawing shown in the drawing 1, the drawing 2 and the drawing 3, a main channel 5 for injecting carbon powder is arranged in the direction parallel to the steel tapping hole, the inner diameter of the main channel 5 for injecting carbon powder is phi 20-30 mm, the material is steel, the main channel 5 for injecting carbon powder is connected with a powder spraying system 10 through a flowmeter 6, a pressure gauge 7, a buffer gas tank 8 and a valve 9, 2-8 groups of annular carbon powder channels 3 are arranged around the steel tapping hole, the inner diameter of each annular carbon powder channel 3 is phi 10-15 mm, the material is steel, all the annular carbon powder channels 3 are connected with the main channel 5 for injecting carbon powder, 2-8 carbon powder spray pipes 4 embedded in refractory materials 2 of the steel tapping hole are connected on each group of the carbon powder channels 3, the inner diameter of each carbon powder spray pipe 4 is phi 4-9 mm, and the material is steel.
When the steel tapping hole needs to be replaced, the steel tapping hole with the carbon powder spray pipe is arranged on the converter, the main channel 5 for spraying carbon powder and the annular carbon powder channel 3 which are exposed outside the steel tapping hole are wrapped by refractory clay, and the converter can perform normal smelting operation after the refractory clay is dried by the waste heat of the converter.
After the smelting of the converter is finished, detecting the carbon content and the oxygen content in molten steel at the smelting end point of the converter by using a sublance, tapping after the components and the temperature of the molten steel are qualified, rocking a converter body of the converter, supplying argon only by a powder injection system 10, namely introducing argon into a main channel 5, keeping the pressure of the argon in a spray pipe 4 at 2-3 atmospheric pressures, achieving the effect of preventing the molten steel from flowing backwards to a carbon powder spray pipe 4 embedded in a steel tapping hole refractory material layer, after the molten steel shows the molten steel, supplying a mixture of the argon and carbon powder by the powder injection system 10, determining the injection amount of the carbon powder according to the contents of [ C ], [ O ] in the molten steel at the smelting end point of the converter and the carbon content in the target components of the molten steel, wherein the injection amount of the carbon powder is calculated according to the following formula (3), keeping the pressure of the argon in the spray pipe 4 at 2-3 atmospheric pressures, and reacting the carbon powder with dissolved oxygen [ O ] in the molten steel to generate CO.
W C ＝(W O -0.0023/W C target )×(12/16)×W Molten steel ×10+(W C target -W C converter )×W Molten steel ×10 ③
W in formula (3) C Comprises the following steps: amount of carbon powder blown (kg), W O Comprises the following steps: converter smelting end point oxygen content (%), W C target Comprises the following steps: end point carbon content (%) in converter smelting, W Molten steel Comprises the following steps: nominal capacity (ton), W, of converter C target Comprises the following steps: carbon content (%) in the molten steel target components.
The reaction of carbon powder and dissolved oxygen [ O ] in molten steel to generate CO is shown as formula (1), and the calculation formula of the reaction equilibrium constant of formula (1) is shown as formula (2).
[C]+[O]→CO ①
K＝a [C] ×a [O] /P CO ②
By examining the handbook of thermodynamics, the equilibrium constant K of equation 1 is 2.3X 10 at 1600 deg.C -3 。
The molten steel is pre-deoxidized by blowing carbon powder into the molten steel through a carbon powder nozzle installed in a tubular refractory material of a steel outlet of a converter, and according to the reaction formula (2), if the carbon content in the target component of the molten steel is 0.1-0.2%, oxygen in the molten steel can be removed to 115-230 ppm, and more than 40% of dissolved oxygen in the molten steel can be removed.
In the actual production process, because CO is difficult to dissolve in the molten steel, CO generated by carbon-oxygen reaction can float up to the interface of the molten steel and air and can be burnt in a high-temperature environment, and the CO poisoning phenomenon cannot occur.
The carbon powder spray pipe is arranged in the tubular refractory material of the steel tapping hole of the converter, and during the steel tapping process, when molten steel flows through the steel tapping hole channel, the deoxidation reaction of the carbon powder and the [ O ] is generated, the deoxidized molten steel flows into a steel ladle, and the sprayed carbon powder is used for removing dissolved oxygen in the molten steel which flows out of the converter but does not flow into the steel ladle. The molten steel in the converter can not generate deoxidation phenomenon, and the 'rephosphorization phenomenon' that the phosphorus in the slag is transferred to the molten steel can not occur. The aluminum strong deoxidizer and the alloy added into the steel ladle can not influence the deoxidation reaction of the carbon powder, and the carbon powder can continuously exert the deoxidation effect in the whole tapping process.
The reaction product CO escapes from the steel flow in a gas state and is discharged to the atmosphere, so that inclusions cannot be left in the molten steel, and the quality of the steel cannot be damaged.
Examples 1,
According to the drawings of 1, 2 and 3, a total channel 5 for injecting carbon powder is arranged in the direction parallel to a steel tapping hole, the inner diameter of the total channel 5 for injecting carbon powder is phi 30mm, the material is steel, the total channel 5 for injecting carbon powder is connected with a powder spraying system 10 through a flowmeter 6, a pressure gauge 7, a buffer gas tank 8 and a valve 9, 4 groups of circular carbon powder channels 3 are arranged around the steel tapping hole, the inner diameter of each circular carbon powder channel 3 is phi 15mm, the material is steel, all the circular carbon powder channels 3 are connected with the total channel 5 for injecting carbon powder, 8 carbon powder spray pipes 4 embedded in steel tapping hole refractory materials 2 are connected to each group of carbon powder channels 3, the inner diameter of each carbon powder spray pipe 4 is phi 5mm, and the material is steel.
When the steel tapping hole needs to be replaced, the steel tapping hole with the carbon powder spray pipe is arranged on the converter, the main channel 5 for spraying carbon powder and the annular carbon powder channel 3 which are exposed outside the steel tapping hole are wrapped by refractory clay, and the converter can perform normal smelting operation after the refractory clay is dried by the waste heat of the converter.
After the smelting of the converter is finished, detecting the carbon content and the oxygen content in molten steel at the smelting end point of the converter by using a sublance, tapping after the components and the temperature of the molten steel are qualified, rocking a converter body, supplying argon only by a powder spraying system 10, namely introducing the argon into a main channel 5, keeping the argon pressure in a spray pipe 4 at 2 atm to achieve the effect of preventing the molten steel from flowing backwards to a carbon powder spray pipe 4 embedded in a refractory material layer of a tap hole, after the molten steel flows out, supplying a mixture of the argon and carbon powder by the powder spraying system 10, determining the spraying amount of the carbon powder according to the content of [ C ] and [ O ] in the molten steel at the smelting end point of the converter and the carbon content in the target components of the molten steel, and calculating the carbon powder spraying amount according to the following formula (3).
W C ＝(W O -0.0023/W C target )×(12/16)×W Molten steel ×10+(W C target -W C converter )×W Molten steel ×10 ③
W in formula (3) C Comprises the following steps: amount of carbon powder blown (kg), W O Comprises the following steps: converter smelting end point oxygen content (%), W C target Comprises the following steps: end point carbon content (%) of converter smelting, W Molten steel Comprises the following steps: nominal capacity (ton) of converter, W C target Comprises the following steps: carbon content (%) in the molten steel target components.
The nominal capacity of a converter is 120 tons, the carbon content in the molten steel at the smelting end point of the converter of the molten steel is 0.06%, the oxygen content is 0.042, the carbon content in the target component of the molten steel is 0.17%, the carbon powder injection amount is 157kg according to the formula (3), the tapping time of the converter is 5 minutes, the carbon powder injection speed is 32kg/min through calculation, and the carbon powder blanking speed in the powder injection system 10 is 32kg/min.
The reaction of carbon powder and dissolved oxygen [ O ] in molten steel to generate CO is shown as formula (1), and the calculation formula of the reaction equilibrium constant of formula (1) is shown as formula (2).
[C]+[O]→CO ①
K＝a [C] ×a [O] /P CO ②
By examining the handbook of thermodynamics, the equilibrium constant K of equation 1 is 2.3X 10 at 1600 deg.C -3 。
Carbon powder is blown to molten steel through a carbon powder nozzle installed in a tubular refractory material of a steel outlet of the converter for pre-deoxidation, and according to the reaction formula (2), if the carbon content in the target component of the molten steel is 0.17%, oxygen in the molten steel can be deoxidized to 135ppm, and 68% of dissolved oxygen in the molten steel of the converter can be deoxidized. The consumption of aluminum is reduced by 25kg, the production cost is reduced by 300 yuan/furnace, and Al in molten steel is reduced 2 O 3 The quantity of the inclusions is reduced, and the total oxygen content in the casting blank is reduced by 3ppm.
In the production process, because CO is difficult to dissolve in the molten steel, the CO generated by the carbon-oxygen reaction can float up to the interface of the molten steel and air and can be burnt in a high-temperature environment, and the CO poisoning phenomenon can not occur.
The carbon powder spray pipe is arranged in the tubular refractory material of the steel tapping hole of the converter, and during the steel tapping process, when molten steel flows through the steel tapping hole channel, the deoxidation reaction of the carbon powder and the [ O ] is generated, the deoxidized molten steel flows into a steel ladle, and the sprayed carbon powder is used for removing dissolved oxygen in the molten steel which flows out of the converter but does not flow into the steel ladle. The deoxidation phenomenon of the molten steel in the converter can not occur, and the rephosphorization phenomenon that the phosphorus in the slag is transferred to the molten steel can not occur. The aluminum strong deoxidizer and the alloy added into the steel ladle can not influence the deoxidation reaction of the carbon powder, and the carbon powder can continuously exert the deoxidation effect in the whole tapping process.
The reaction product CO escapes from the steel flow in a gas state and is discharged to the atmosphere, so that inclusions cannot be left in the molten steel, and the quality of the steel cannot be damaged.
Examples 2,
According to the drawings of 1, 2 and 3, a main channel 5 for injecting carbon powder is arranged in the direction parallel to a steel tapping hole, the inner diameter of the main channel 5 for injecting carbon powder is phi 20mm, the material is steel, the main channel 5 for injecting carbon powder is connected with a powder spraying system 10 through a flowmeter 6, a pressure gauge 7, a buffer gas tank 8 and a valve 9, 2 groups of circular carbon powder channels 3 are arranged around the steel tapping hole, the inner diameter of each circular carbon powder channel 3 is phi 13mm, the material is steel, all the circular carbon powder channels 3 are connected with the main channel 5 for injecting carbon powder, 5 carbon powder spray pipes 4 embedded in steel tapping hole refractory materials 2 are connected to each group of carbon powder channels 3, the inner diameter of each carbon powder spray pipe 4 is phi 6mm, and the material is steel.
When the steel tapping hole needs to be replaced, the steel tapping hole with the carbon powder spray pipe is arranged on the converter, the main channel 5 for spraying carbon powder and the annular carbon powder channel 3 which are exposed outside the steel tapping hole are wrapped by refractory clay, and the converter can perform normal smelting operation after the refractory clay is dried by the waste heat of the converter.
After the smelting of the converter is finished, detecting the carbon content and the oxygen content in molten steel at the smelting end point of the converter by using a sublance, tapping after the components and the temperature of the molten steel are qualified, rocking a converter body, supplying argon only by a powder spraying system 10, namely introducing the argon into a main channel 5, keeping the argon pressure in a spray pipe 4 at 3 atmospheric pressures, and achieving the effect of preventing the molten steel from flowing backwards to a carbon powder spray pipe 4 embedded in a refractory material layer of a tap hole.
W C ＝(W O -0.0023/W C target )×(12/16)×W Molten steel ×10+(W C target -W C converter )×W Molten steel ×10 ③
W in formula (3) C Comprises the following steps: amount of carbon powder (kg), W, blown O Comprises the following steps: converter smelting end point oxygen content (%), W C target Comprises the following steps: end point carbon content (%) of converter smelting, W Molten steel Comprises the following steps: nominal capacity (ton) of converter, W C target Comprises the following steps: carbon content (%) in the molten steel target components.
The nominal capacity of the converter is 100 tons, the carbon content in the molten steel at the smelting end point of the converter of the molten steel is 0.07 percent, the oxygen content is 0.035 percent, the carbon content in the target component of the molten steel is 0.12 percent, the spraying amount of the carbon powder is 64kg according to the calculation of the formula (3), the tapping time of the converter is 5 minutes, the spraying speed of the carbon powder is 13kg/min through calculation, and the blanking speed of the carbon powder in the powder spraying system 10 is 13kg/min.
The reaction of carbon powder and dissolved oxygen in molten steel to produce CO is shown in the expression (1), and the equation for calculating the reaction equilibrium constant in the expression (1) is shown in the expression (2).
[C]+[O]→CO ①
K＝a [C] ×a [O] /P CO ②
By examining the handbook of thermodynamics, the equilibrium constant K of equation 1 is 2.3X 10 at 1600 deg.C -3 。
Carbon powder is blown to molten steel through a carbon powder nozzle installed in a tubular refractory material of a steel outlet of the converter for pre-deoxidation, and according to the reaction formula (2), if the carbon content in the target component of the molten steel is 0.12%, oxygen in the molten steel can be deoxidized to 192ppm, and 45% of dissolved oxygen in the molten steel of the converter can be deoxidized. Reduce the consumption of aluminum by 14kg, reduce the production cost by 150 yuan/furnace and reduce Al in molten steel 2 O 3 The number of the inclusions is determined by the number of the inclusions,the total oxygen content in the casting blank is reduced by 2ppm.
In the production process, because CO is difficult to dissolve in the molten steel, CO generated by carbon-oxygen reaction floats up to the interface of the molten steel and air and can be burnt in a high-temperature environment, and the CO poisoning phenomenon cannot occur.
The carbon powder spray pipe is arranged in the tubular refractory material of the steel tapping hole of the converter, and during the steel tapping process, when molten steel flows through the steel tapping hole channel, the deoxidation reaction of the carbon powder and the [ O ] is generated, the deoxidized molten steel flows into a steel ladle, and the sprayed carbon powder is used for removing dissolved oxygen in the molten steel which flows out of the converter but does not flow into the steel ladle. The deoxidation phenomenon of the molten steel in the converter can not occur, and the rephosphorization phenomenon that the phosphorus in the slag is transferred to the molten steel can not occur. The aluminum strong deoxidizer and the alloy added into the ladle do not influence the deoxidation reaction of the carbon powder, and the carbon powder can continuously exert the deoxidation effect in the whole tapping process.
The reaction product CO escapes from the steel flow in a gas state and is discharged to the atmosphere, so that inclusions cannot be left in the molten steel, and the quality of the steel cannot be damaged.
Claims (5)
1. A pre-deoxidation device for blowing carbon powder in a converter steel tapping hole is characterized in that a main channel for blowing carbon powder is arranged in a direction parallel to the steel tapping hole, the main channel for blowing carbon powder is connected with a powder spraying system, 2-8 groups of circular carbon powder channels are arranged around the steel tapping hole, all the circular carbon powder channels are connected with the main channel for blowing carbon powder, and 2-8 carbon powder spray pipes embedded in refractory materials of the steel tapping hole are connected to each group of carbon powder channels;
the pre-deoxidation device for blowing the carbon powder into the converter steel tapping hole also comprises a valve; the main channel for blowing the carbon powder is connected with a powder spraying system through a valve;
the pre-deoxidation device for blowing the carbon powder into the converter steel tapping hole also comprises a flowmeter and/or a pressure gauge; the main channel for blowing the carbon powder is connected with a powder spraying system through a flowmeter and/or a pressure gauge;
the pre-deoxidation device for blowing the carbon powder into the converter steel tapping hole also comprises a buffer gas tank; the main channel for injecting the carbon powder is connected with a powder spraying system through one or more of a flowmeter, a pressure gauge, a buffer gas tank and/or a valve;
when the steel tapping hole needs to be replaced, the steel tapping hole with the carbon powder spray pipe is arranged on the converter, the main channel for spraying carbon powder and the circular ring-shaped carbon powder channel which are exposed outside the steel tapping hole are wrapped by refractory clay, and the converter performs normal smelting operation after the refractory clay is dried by the waste heat of the converter.
2. The preliminary deoxidation apparatus for injecting carbon powder into the tap hole of a converter as claimed in claim 1 wherein the overall passageway for injecting carbon powder has an internal diameter of Φ 20-30 mm and is made of steel.
3. The pre-deoxidation apparatus for injecting carbon powder into the tap hole of a converter as claimed in claim 1 wherein the annular carbon powder channel has an internal diameter of Φ 10-15 mm and is made of steel.
4. The preliminary deoxidation apparatus for injecting carbon powder into the tap hole of a converter as claimed in claim 1 wherein the carbon powder lance has an internal diameter of 4 to 9mm and is made of steel.
5. A pre-deoxidation method for blowing carbon powder into a converter steel tapping hole is characterized in that: installing a plurality of groups of carbon powder spray pipes in a tubular refractory material of a converter steel tapping hole, spraying carbon powder into steel tapping flow through the carbon powder spray pipes in the converter steel tapping process, and reacting the carbon powder with dissolved oxygen [ O ] in molten steel to generate CO;
after the smelting of the converter is finished, detecting the carbon content and the oxygen content in molten steel at the smelting end point of the converter by using a sublance, tapping after the components and the temperature of the molten steel are qualified, rocking a converter body of the converter, supplying argon only by a powder spraying system, namely introducing the argon into a main channel, keeping the pressure of the argon in a spray pipe at 2-3 atmospheric pressures, achieving the effect of preventing the molten steel from flowing backwards to a carbon powder spray pipe embedded in a refractory material layer of a tap hole, supplying a mixture of the argon and the carbon powder by the powder spraying system after the molten steel flows, determining the spraying amount of the carbon powder according to the content of [ C ], [ O ] in the molten steel at the smelting end point of the converter and the carbon content in target components of the molten steel, and keeping the pressure of the argon in the spray pipe 4 at 2-3 atmospheric pressures in the process of spraying the carbon powder, so that the carbon powder reacts with dissolved oxygen [ O ] in the molten steel to generate CO.
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| CN109880965B (en) * | 2019-04-24 | 2020-08-04 | 东北大学 | Device and method for powder injection dephosphorization and simultaneous slag blocking above converter steel tapping hole |
| CN112226576B (en) * | 2020-09-27 | 2023-07-14 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Device and method for carbon spraying and deoxidizing by utilizing slag blocking system |
| CN113832286B (en) * | 2021-09-17 | 2023-01-17 | 东北大学 | Device and method for powder injection dephosphorization and slag blocking at converter steel tapping hole and composite dephosphorization agent |
| CN114012069A (en) * | 2021-10-15 | 2022-02-08 | 胡克潮 | Channel type metal solid-liquid mixing injection device and suspension casting method thereof |
| CN116103467A (en) * | 2023-04-14 | 2023-05-12 | 山西建龙实业有限公司 | Novel low-carbon aluminum-containing steel deoxidization alloying method |
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| JPH05287354A (en) * | 1992-04-15 | 1993-11-02 | Nippon Steel Corp | Method for refining molten steel at tapping and method for preventing mixture of slag at tapping steel |
| CN1192118C (en) * | 2000-04-26 | 2005-03-09 | 浦项综合制铁株式会社 | Method and apparatus for convecter tapping capable of preventing slag from flowing off |
| CN100532583C (en) * | 2006-11-02 | 2009-08-26 | 济南大学 | Oxygen top blown rotary converter air curtain slag retaining steel outlet |
| CN102559998A (en) * | 2012-02-03 | 2012-07-11 | 北京首钢国际工程技术有限公司 | Technology for online dusting desulfuration of steel ladles |
| CN106048136B (en) * | 2016-07-27 | 2017-12-08 | 北京科技大学 | One kind steel-making tapping process dusts method of deoxidation and system online |
| CN207862386U (en) * | 2018-01-13 | 2018-09-14 | 山东钢铁股份有限公司 | A kind of pre-deoxidation device being blown carbon dust in converter taphole |
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