CN116790839A - Method for controlling rising operation of converter bottom - Google Patents

Abstract

The invention discloses a method for controlling the rising operation of a converter bottom, which belongs to the technical field of steelmaking converter smelting and comprises the following steps: s1, optimizing a converter loading system: loading standard when each production condition is normal; s2, optimizing an oxygen supply system: the invention has the advantages of low cost, simple operation, safer and more reliable effect, effectively reduces the rising phenomenon of the furnace bottom, reduces the consumption of steel and iron materials, ensures the bottom blowing effect, effectively improves the double blowing rate and improves the production efficiency and the product quality; the invention ensures the quality of light burning and lime through a slagging system, ensures the smooth slag forming operation, and particularly specifies that the addition amount of the light burning magnesium balls and the lime adopts different slag forming operation processes according to different steel types and molten iron components, so that the final slag has good fluidity, and the slag is prevented from being too thin and causing the bottom of the furnace to be lowered.

Description

Method for controlling rising operation of converter bottom

Technical Field

The invention belongs to the technical field of steelmaking converter smelting, and particularly relates to a method for controlling rising operation of a converter bottom.

Background

In the blowing process, the slag structure is adjusted, the occurrence of back drying is avoided, the physical properties and components of slag are guaranteed, the blowing operation is facilitated, a furnace lining is not corroded, the slag splashing furnace protection requirement is met, if the alkalinity of slag for slag splashing is too high, the magnesium oxide content reaches or exceeds a saturation value, the temperature of a hearth is reduced after pouring steel, magnesium oxide crystals are separated out, high-melting-point minerals C2S, C S are separated out simultaneously, the minerals are concentrated and left at the bottom of the furnace, the minerals are combined with magnesia carbon brick periclase crystals at the bottom of the furnace to cause rising, a series of problems are brought to the whole smelting operation after the rising of the bottom of the furnace, the smelting operation is not easy to control, and production or safety accidents can be caused. The rising or falling of the furnace bottom can cause the increase of splashing, reduce the metal recovery rate, increase the consumption of steel materials, in addition, when the splashing is serious, safety accidents or equipment accidents are easy to cause, the too low position of the gun operated by the falling of the furnace bottom can cause serious dry-back phenomenon in the blowing process, after the spray head is corroded, the oxygen utilization rate is low, in addition, after the gun is seriously stuck, the nitrogen seal can be pulled out when the gun is lifted, even the nitrogen seal cannot be lifted out by the oxygen gun, and the production heat is stopped.

Disclosure of Invention

To solve the problems set forth in the background art. The invention provides a method for controlling the rising operation of the converter bottom, which has the characteristics of low cost, simple and convenient operation, safer and more reliable effect, reduced operation safety risk and production accident of post personnel and improved working efficiency.

In order to achieve the above purpose, the present invention provides the following technical solutions: a method of controlling converter hearth up-scaling operation, the method comprising the steps of:

s1, optimizing a converter loading system: loading standard when each production condition is normal;

s2, optimizing an oxygen supply system: reasonable oxygen supply to the molten pool so as to obtain the optimal smelting condition, which is also called oxygen supply system in production, comprises two aspects: according to raw materials and tonnage of the furnace, a designed oxygen lance is designed; a reasonable oxygen lance operating regime is formulated, so that after an oxygen lance is selected, the oxygen supply regime is determined by only formulating the reasonable oxygen lance operating regime, which comprises: determining proper oxygen supply intensity, determining oxygen supply pressure, determining reasonable gun positions and adjusting the gun positions in the converting process;

s3, adjusting a slag structure:

(1) in order to reduce the FeO content in the terminal slag, adopting a terminal gun-lowering and oxygen-lifting measure in actual production, reducing the terminal gun position from a normal converting gun position (oxygen gun scale zero position) to-100 mm, and simultaneously increasing the working oxygen pressure from 0.85MPa to 0.90-0.95 MPa; strictly controlling the primary pouring hit rate, adopting measures such as adding ore and cooling in the later period of the strictly forbidden converting, adopting a fine material policy to reduce the slag quantity, striving to improve the quality of the raw materials fed into the furnace on the basis of further perfecting the slag-leaving splash of the converter and the application of a slag operation process, adopting high-grade lime, adopting light-burned magnesium balls for slagging, reasonably adjusting the slag-forming material consumption according to the Si and S content conditions of molten iron, and properly reducing the lime quantity consumption under the condition of ensuring the production requirement;

(2) the silicon and manganese contents in the molten iron are low, desulfurization is not needed, the slag making mechanism and the dynamic characteristics are changed, because the lime consumption is reduced, the slag quantity is reduced, the slag alkalinity and the oxidation degree are increased, the occurrence of back drying is avoided, the physical properties and components of the slag are ensured to be beneficial to blowing operation, the furnace lining is not eroded, the slag splashing furnace protection requirement is met, if the slag alkalinity of the slag splashed by slag is too high, the magnesium oxide content reaches or exceeds the saturation value, the temperature of a hearth is reduced after pouring steel, magnesium oxide is crystallized and separated out, high-melting-point minerals C2S, C S are also separated out simultaneously and are concentrated at the bottom of the furnace and are combined with magnesia carbon brick periclase crystals at the bottom of the furnace to cause rising;

s4, controlling the temperature in the smelting process:

(1) when the scrap steel is not matched in place, an iron cooling material can be used for adjusting the temperature, the scrap steel is added along with the head batch, the addition amount of the iron cooling material is not more than 800kg each time, and the over-splashing and the slag overflow are controlled;

(2) according to the requirements of molten iron conditions and slag end point components, various bulk materials are reasonably added, and when the process temperature is too high, on the premise of ensuring the requirements of the furnace burden end point components, iron cooling materials are used for cooling as much as possible, so that the slag is prevented from being excessively sticky;

(3) the feeding and cooling operation before tapping must be performed with point blowing, firstly, excessive feeding is avoided, and when the feeding floats on the surface of slag, the feeding cannot be thoroughly melted and the cooling effect cannot be truly achieved; secondly, the phenomenon that the slag is too thick when the slag is splashed due to the fact that the cooling material floats on the surface of the slag is avoided, a good slag splashing effect cannot be achieved, and meanwhile the furnace bottom is easy to rise;

s5, optimizing a slag splashing furnace protection process:

(1) the method combines with the field practice to study the slag splashing process, improves the operation process parameters, improves the working pressure of nitrogen slag splashing from original 0.70-0.90 MPa to 0.95-1.05 MPa, combines the conditions of slag temperature reduction, viscosity increase and the like in the slag splashing process, adjusts the slag splashing gun position from 700-1700 mm to 600-1400 mm, adjusts the distribution time of the slag splashing gun position, prolongs the proportion of slag splashing time of 50-500 mm at the low gun position and ensures that the minimum gun position time reaches 30S according to the characteristic that the proportion of medium-high carbon steel is high, and the problems of rising furnace bottom and corrosion loss of furnace caps are more prominent;

(2) the slag splashing gun position is reduced, the low gun position time is prolonged, the slag splashing effect is ensured, the slag which is not easy to splash and accumulated on the furnace bottom originally is effectively splashed and adhered on the furnace lining, particularly, the slag splashing effect on the furnace cap part is more ideal, the problems of rising of the furnace bottom and insufficient slag splashing capacity on the upper part of the furnace body are effectively solved, the slag splashing time proportion of the middle gun position is unchanged, the slag splashing requirement of the furnace lining at the trunnion part can be met, the slag splashing pressure and gun position are adjusted, the slag is uniformly coated on the furnace lining after slag splashing, and brick lining cannot be observed by naked eyes;

(3) the proper slag amount is ensured to influence the quality of slag splashing effect, the rising or not of the furnace bottom is directly influenced, the slag is too little, the temperature of the slag is reduced too fast by the injected nitrogen, the slag is caked and left at the furnace bottom when not splashed, the slag amount is too great, the temperature of the slag is reduced by the injected nitrogen in a certain time, and the slag cannot be thickened and adhered to the furnace wall;

s6, slag splashing furnace protection and spray repair: the slag splashing effect is guaranteed to be a precondition that the furnace lining is reasonably maintained, the slag structure is required to be improved, physical properties and components of slag meet the slag splashing furnace protection requirement, the furnace lining is reasonably maintained by combining spray repair, the furnace repair times are reduced, the volume of the molten pool is not changed, molten metal in the molten pool is better participated in circulation as much as possible, a stagnation area is increased, and the possibility of the slag viscous furnace bottom is increased;

s7, accurately grasping the furnace bottom height: the furnace bottom and the gun position are measured every shift, the furnace bottom and the gun position are continuously eroded along with lining bricks for furnace repair, the radius of a molten pool is increased, in order to clearly show the erosion degree of the furnace lining and the rising condition of the furnace bottom, the furnace bottom and the gun position are measured every shift, the gun position of an oxygen gun is dynamically adjusted or the oxygen supply pressure is adjusted according to the erosion condition of the furnace lining and the rising condition of the furnace bottom, and the oxygen supply pressure is adjusted so that large splashing, furnace bottom erosion, furnace leakage and furnace bottom rising are avoided.

Further, the optimized converter loading schedule is as follows:

(1) in the production process, the influence of the change of the molten iron condition on the heat of the converter is considered according to corresponding numerical values:

(2) every 0.10% of Si content of molten iron changes, and the terminal temperature is affected to 25 ℃;

(3) when the temperature of molten iron changes by 10 ℃, the end point temperature is affected by 7 ℃;

(4) when the molten iron condition changes to lead the end temperature to be reduced to be less than or equal to 55 ℃, the molten iron is filled in the converter without adjustment, slag retaining operation is adopted in the converter smelting process, and light burned magnesium balls replace light burned dolomite or iron block adding measures are taken to make up the heat which is lacking;

(5) when the molten iron condition changes to cause the end temperature to drop by more than 40 ℃, adopting measures of adjusting and loading to solve the problem of heat deficiency;

(6) the thermal effect of molten iron, scrap steel, pig iron, slag steel and smelting steel changes during integral filling;

(7) when the heat is deficient due to the change of the molten iron conditions, increasing 1 ton of molten iron and reducing 1 ton of scrap steel can increase the final temperature by 15 ℃ +15 ℃ =30 ℃;

(8) when the heat deficiency needs to be adjusted, the adjustment is performed according to the heat effect in the table 2 by increasing the molten iron amount and simultaneously reducing the scrap steel amount;

(9) the total loading amount of the converter is strictly controlled according to 128+/-1 ton, the proportion of molten iron and scrap steel is properly adjusted according to actual conditions, the total loading amount is ensured to be unchanged, and an assistant transmits the adjustment information to the converter length to correspondingly adjust, so that the stability of the loading amount of the converter for steelmaking is ensured.

Further, the optimized oxygen supply system comprises the following steps:

(1) oxygen supply intensity:

the oxygen supply intensity is the amount of oxygen in a standard state supplied to each ton of metal per unit time, that is: oxygen supply intensity (m < mu >/(t.min))=oxygen demand per ton metal (m < mu >/t)/supply time (min);

(2) oxygen supply pressure:

the pressure of oxygen is an important parameter of oxygen supply operation in converter steelmaking, for the same oxygen lance, the oxygen supply strength can be increased by increasing the oxygen pressure, and the smelting time is shortened, but when the lance position is fixed, serious splashing can be caused by excessively increasing the oxygen pressure, meanwhile, the impact depth of oxygen jet flow on a molten pool can be increased, so that the danger of erosion of the bottom of the furnace exists, and the whole oxygen supply pressure of the converter is strictly controlled between 0.85 and 0.90 Mpa; gun position control: the method is characterized in that a variable-pressure gun-changing operation mode is adopted, a low-high-low three-section operation method is adopted in the whole gun position, fluctuation of the gun position in the blowing process cannot exceed 200mm each time, impact force of blowing reduction of a converter is increased aiming at the radius of a molten pool after furnace repair each time, and the situation that molten metal is correspondingly reduced is solved by adopting a Mach number reduction method, if the molten pool is sufficiently stirred, impact depth is required to be reduced, the molten metal at the bottom of the molten pool participates in circulation, and the viscous furnace bottom is increased;

(3) gun position and control thereof:

the four-hole Laval type oxygen lance is used for changing the form of the flow strand, because the included angle between the holes is unreasonable, a stagnation area is arranged at the center part of the bottom of the molten pool, molten metal in the stagnation area does not participate in circulation, the reduction of the stagnation area can be realized by increasing the included angle of spray holes, when normal converting is performed in standardized operation, the lance position is adjusted to 1350-1450 mm from the liquid level, when slag splashing is performed in 1200-1300 mm during carbon drawing, the lance position is adjusted to 1400mm from the bottom of the furnace before slag splashing, and then the lance position is gradually reduced to 600mm.

Further, the slag splashing protection and gunning operation steps are as follows:

(1) and (3) supplementing:

the viscosity of the final slag is properly larger than that of the previous furnace with the large surface, the final slag cannot be too thin, after tapping of the previous furnace with the large surface, a converter worker shakes the furnace to enable the large furnace mouth of the converter to be downward, residual steel and residues in the furnace are dumped, and the furnace is shaken to a working position required by the furnace repairing;

(2) furnace bottom

Shaking the furnace to a scrap adding position, filling a repairing material into the furnace by using a scrap hopper, wherein the repairing material amount is generally 1-2 t, shaking the furnace back and forth, generally not less than 3 times, rotating at an angle of 5-60 degrees or a range of a furnace mouth shaking out of a smoke hood, and lowering a gun for baking;

(3) supplementing facets:

when obvious pits or partial pits appear on the facet and the steel tapping hole is higher than the furnace lining to cause incomplete steel production, the operation of repairing the facet is carried out, the repairing material is shaken to a pre-repairing position to be paved after entering the furnace, and after the steel tapping hole is not blocked by the repairing material, the requirement of repairing the facet is 1t repairing material less than 40min and 2t repairing material less than 50min;

(4) gunning up

If the parts such as the furnace cap, the trunnion slag line and the like are sunken or fall off, a permanent layer is seen, gunning is carried out according to the situation, the gunning part is required to be smooth and has no obvious steps, the sintering time is ensured to be 5-10 min after gunning, and the gunning operation is carried out according to specific operation rules.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention has low cost, simple operation, safer and more reliable effect, reduces the operation safety risk of post personnel and the occurrence of production accidents, improves the working efficiency, has great significance on stable production, effectively reduces the rising phenomenon of the furnace bottom, reduces the consumption of steel and iron materials, ensures the bottom blowing effect, effectively improves the re-blowing rate, saves the production cost and improves the production efficiency and the product quality;

2. the quality of light burning and lime is ensured by a slagging system, the slagging operation is ensured to be carried out smoothly, and the addition amount of the light burning magnesium balls and the lime is especially regulated to adopt different slagging operation processes according to different steel types and molten iron components, so that the final slag has good fluidity, and the phenomenon that the slag is too thin and the bottom of a furnace is lowered is avoided;

3. according to the invention, the temperature is adjusted through the iron cooling material, the iron cooling material is added along with the head batch, the material is fed quantitatively each time, the over-blowing splashing and slag overflow are controlled, and the lowering of the furnace bottom is prevented;

4. according to the invention, various bulk materials are reasonably added according to the molten iron conditions and the requirements of slag end point components, and when the process temperature is too high, on the premise of ensuring the requirements of furnace charge end point components, iron cooling materials are used for cooling as much as possible, so that the furnace bottom is prevented from being lowered due to too thin slag;

5. the invention has the advantages that the charging and cooling operation must be performed before tapping, firstly, excessive charging is avoided, and when the charging material floats on the surface of slag, the charging material cannot be thoroughly melted but cannot really perform the cooling function; secondly, the phenomenon that the cooling material floats on the surface of slag to cause excessive dilution of slag during slag splashing can be avoided, a good slag splashing effect can not be achieved, and meanwhile, the furnace bottom is easy to descend.

Drawings

FIG. 1 is a flow chart of a method for controlling the rising operation of the converter bottom according to the invention

FIG. 2 is a table showing the loading criteria when the production conditions of the method for controlling the rising operation of the converter bottom of the present invention are normal.

FIG. 3 is a table showing the variation of the thermal effect of the method for controlling the rising operation of the converter bottom according to the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Referring to fig. 1-3, the present invention provides the following technical solutions: a method for controlling the rising operation of the converter bottom comprises the following steps:

s1, optimizing a converter loading system: loading standard when each production condition is normal;

s2, optimizing an oxygen supply system: reasonable oxygen supply to the molten pool so as to obtain the optimal smelting condition, which is also called oxygen supply system in production, comprises two aspects: according to raw materials and tonnage of the furnace, a designed oxygen lance is designed; a reasonable oxygen lance operating regime is formulated, so that after an oxygen lance is selected, the oxygen supply regime is determined by only formulating the reasonable oxygen lance operating regime, which comprises: determining proper oxygen supply intensity, determining oxygen supply pressure, determining reasonable gun positions and adjusting the gun positions in the converting process;

s3, adjusting a slag structure:

(1) in order to reduce the FeO content in the terminal slag, adopting a terminal gun-lowering and oxygen-lifting measure in actual production, reducing the terminal gun position from a normal converting gun position (oxygen gun scale zero position) to-100 mm, and simultaneously increasing the working oxygen pressure from 0.85MPa to 0.90-0.95 MPa; strictly controlling the primary pouring hit rate, adopting measures such as adding ore and cooling in the later period of the strictly forbidden converting, adopting a fine material policy to reduce the slag quantity, striving to improve the quality of the raw materials fed into the furnace on the basis of further perfecting the slag-leaving splash of the converter and the application of a slag operation process, adopting high-grade lime, adopting light-burned magnesium balls for slagging, reasonably adjusting the slag-forming material consumption according to the Si and S content conditions of molten iron, and properly reducing the lime quantity consumption under the condition of ensuring the production requirement;

(2) the silicon and manganese contents in the molten iron are low, desulfurization is not needed, the slag making mechanism and the dynamic characteristics are changed, because the lime consumption is reduced, the slag quantity is reduced, the slag alkalinity and the oxidation degree are increased, the occurrence of back drying is avoided, the physical properties and components of the slag are ensured to be beneficial to blowing operation, the furnace lining is not eroded, the slag splashing furnace protection requirement is met, if the slag alkalinity of the slag splashed by slag is too high, the magnesium oxide content reaches or exceeds the saturation value, the temperature of a hearth is reduced after pouring steel, magnesium oxide is crystallized and separated out, high-melting-point minerals C2S, C S are also separated out simultaneously and are concentrated at the bottom of the furnace and are combined with magnesia carbon brick periclase crystals at the bottom of the furnace to cause rising;

s4, controlling the temperature in the smelting process:

(1) when the scrap steel is not matched in place, an iron cooling material can be used for adjusting the temperature, the scrap steel is added along with the head batch, the addition amount of the iron cooling material is not more than 800kg each time, and the over-splashing and the slag overflow are controlled;

(2) according to the requirements of molten iron conditions and slag end point components, various bulk materials are reasonably added, and when the process temperature is too high, on the premise of ensuring the requirements of the furnace burden end point components, iron cooling materials are used for cooling as much as possible, so that the slag is prevented from being excessively sticky;

(3) the feeding and cooling operation before tapping must be performed with point blowing, firstly, excessive feeding is avoided, and when the feeding floats on the surface of slag, the feeding cannot be thoroughly melted and the cooling effect cannot be truly achieved; secondly, the phenomenon that the slag is too thick when the slag is splashed due to the fact that the cooling material floats on the surface of the slag is avoided, a good slag splashing effect cannot be achieved, and meanwhile the furnace bottom is easy to rise;

s5, optimizing a slag splashing furnace protection process:

(1) the method combines with the field practice to study the slag splashing process, improves the operation process parameters, improves the working pressure of nitrogen slag splashing from original 0.70-0.90 MPa to 0.95-1.05 MPa, combines the conditions of slag temperature reduction, viscosity increase and the like in the slag splashing process, adjusts the slag splashing gun position from 700-1700 mm to 600-1400 mm, adjusts the distribution time of the slag splashing gun position, prolongs the proportion of slag splashing time of 50-500 mm at the low gun position and ensures that the minimum gun position time reaches 30S according to the characteristic that the proportion of medium-high carbon steel is high, and the problems of rising furnace bottom and corrosion loss of furnace caps are more prominent;

(2) the slag splashing gun position is reduced, the low gun position time is prolonged, the slag splashing effect is ensured, the slag which is not easy to splash and accumulated on the furnace bottom originally is effectively splashed and adhered on the furnace lining, particularly, the slag splashing effect on the furnace cap part is more ideal, the problems of rising of the furnace bottom and insufficient slag splashing capacity on the upper part of the furnace body are effectively solved, the slag splashing time proportion of the middle gun position is unchanged, the slag splashing requirement of the furnace lining at the trunnion part can be met, the slag splashing pressure and gun position are adjusted, the slag is uniformly coated on the furnace lining after slag splashing, and brick lining cannot be observed by naked eyes;

(3) the proper slag amount is ensured to influence the quality of slag splashing effect, the rising or not of the furnace bottom is directly influenced, the slag is too little, the temperature of the slag is reduced too fast by the injected nitrogen, the slag is caked and left at the furnace bottom when not splashed, the slag amount is too great, the temperature of the slag is reduced by the injected nitrogen in a certain time, and the slag cannot be thickened and adhered to the furnace wall;

s6, slag splashing furnace protection and spray repair: the slag splashing effect is guaranteed to be a precondition that the furnace lining is reasonably maintained, the slag structure is required to be improved, physical properties and components of slag meet the slag splashing furnace protection requirement, the furnace lining is reasonably maintained by combining spray repair, the furnace repair times are reduced, the volume of the molten pool is not changed, molten metal in the molten pool is better participated in circulation as much as possible, a stagnation area is increased, and the possibility of the slag viscous furnace bottom is increased;

s7, accurately grasping the furnace bottom height: the furnace bottom and the gun position are measured every shift, the furnace bottom and the gun position are continuously eroded along with lining bricks for furnace repair, the radius of a molten pool is increased, in order to clearly show the erosion degree of the furnace lining and the rising condition of the furnace bottom, the furnace bottom and the gun position are measured every shift, the gun position of an oxygen gun is dynamically adjusted or the oxygen supply pressure is adjusted according to the erosion condition of the furnace lining and the rising condition of the furnace bottom, and the oxygen supply pressure is adjusted so that large splashing, furnace bottom erosion, furnace leakage and furnace bottom rising are avoided.

In the invention, the converter loading system is optimized as follows:

(1) the method is characterized in that the method is carried out in the production process, and based on the table 1, the influence of the change of the molten iron condition on the heat of the converter is considered according to corresponding numerical values:

(2) every 0.10% of Si content of molten iron changes, and the terminal temperature is affected to 25 ℃;

(3) when the temperature of molten iron changes by 10 ℃, the end point temperature is affected by 7 ℃;

(4) when the molten iron condition changes to lead the end temperature to be reduced to be less than or equal to 55 ℃, the molten iron is filled in the converter without adjustment, slag retaining operation is adopted in the converter smelting process, and light burned magnesium balls replace light burned dolomite or iron block adding measures are taken to make up the heat which is lacking;

(5) when the molten iron condition changes to cause the end temperature to drop by more than 40 ℃, adopting measures of adjusting and loading to solve the problem of heat deficiency;

(6) the change of the heat effect of molten iron, scrap steel, pig iron, slag steel and smelted steel during the integral charging is referred to table 2;

(7) when the heat is deficient due to the change of the molten iron conditions, increasing 1 ton of molten iron and reducing 1 ton of scrap steel can increase the final temperature by 15 ℃ +15 ℃ =30 ℃;

(8) when the heat deficiency needs to be adjusted, the adjustment is performed according to the heat effect in the table 2 by increasing the molten iron amount and simultaneously reducing the scrap steel amount;

(9) the total loading amount of the converter is strictly controlled according to 128+/-1 ton, the proportion of molten iron and scrap steel is properly adjusted according to actual conditions, the total loading amount is ensured to be unchanged, and an assistant transmits the adjustment information to the converter length to correspondingly adjust, so that the stability of the loading amount of the converter for steelmaking is ensured.

In the invention, the oxygen supply system is optimized as follows:

(1) oxygen supply intensity:

the oxygen supply intensity is the amount of oxygen in a standard state supplied to each ton of metal per unit time, that is: oxygen supply intensity (m < mu >/(t.min))=oxygen demand per ton metal (m < mu >/t)/supply time (min);

(2) oxygen supply pressure:

the pressure of oxygen is an important parameter of oxygen supply operation in converter steelmaking, for the same oxygen lance, the oxygen supply strength can be increased by increasing the oxygen pressure, and the smelting time is shortened, but when the lance position is fixed, serious splashing can be caused by excessively increasing the oxygen pressure, meanwhile, the impact depth of oxygen jet flow on a molten pool can be increased, so that the danger of erosion of the bottom of the furnace exists, and the whole oxygen supply pressure of the converter is strictly controlled between 0.85 and 0.90 Mpa; gun position control: the method is characterized in that a variable-pressure gun-changing operation mode is adopted, a low-high-low three-section operation method is adopted in the whole gun position, fluctuation of the gun position in the blowing process cannot exceed 200mm each time, impact force of blowing reduction of a converter is increased aiming at the radius of a molten pool after furnace repair each time, and the situation that molten metal is correspondingly reduced is solved by adopting a Mach number reduction method, if the molten pool is sufficiently stirred, impact depth is required to be reduced, the molten metal at the bottom of the molten pool participates in circulation, and the viscous furnace bottom is increased;

(3) gun position and control thereof:

the four-hole Laval type oxygen lance is used for changing the form of the flow strand, because the included angle between the holes is unreasonable, a stagnation area is arranged at the center part of the bottom of the molten pool, molten metal in the stagnation area does not participate in circulation, the reduction of the stagnation area can be realized by increasing the included angle of spray holes, when normal converting is performed in standardized operation, the lance position is adjusted to 1350-1450 mm from the liquid level, when slag splashing is performed in 1200-1300 mm during carbon drawing, the lance position is adjusted to 1400mm from the bottom of the furnace before slag splashing, and then the lance position is gradually reduced to 600mm.

In the invention, the slag splashing furnace protection and spray repair operation steps are as follows:

(1) and (3) supplementing:

the viscosity of the final slag is properly larger than that of the previous furnace with the large surface, the final slag cannot be too thin, after tapping of the previous furnace with the large surface, a converter worker shakes the furnace to enable the large furnace mouth of the converter to be downward, residual steel and residues in the furnace are dumped, and the furnace is shaken to a working position required by the furnace repairing;

(2) furnace bottom

Shaking the furnace to a scrap adding position, filling a repairing material into the furnace by using a scrap hopper, wherein the repairing material amount is generally 1-2 t, shaking the furnace back and forth, generally not less than 3 times, rotating at an angle of 5-60 degrees or a range of a furnace mouth shaking out of a smoke hood, and lowering a gun for baking;

(3) supplementing facets:

when obvious pits or partial pits appear on the facet and the steel tapping hole is higher than the furnace lining to cause incomplete steel production, the operation of repairing the facet is carried out, the repairing material is shaken to a pre-repairing position to be paved after entering the furnace, and after the steel tapping hole is not blocked by the repairing material, the requirement of repairing the facet is 1t repairing material less than 40min and 2t repairing material less than 50min;

(4) gunning up

If the parts such as the furnace cap, the trunnion slag line and the like are sunken or fall off, a permanent layer is seen, gunning is carried out according to the situation, the gunning part is required to be smooth and has no obvious steps, the sintering time is ensured to be 5-10 min after gunning, and the gunning operation is carried out according to specific operation rules.

The working principle and the using flow of the invention are as follows: the invention optimizes the converter loading system: loading standard when each production condition is normal; optimizing an oxygen supply system: reasonable oxygen supply to the molten pool so as to obtain the optimal smelting condition, which is also called oxygen supply system in production, comprises two aspects: according to raw materials and tonnage of the furnace, a designed oxygen lance is designed; a reasonable oxygen lance operating regime is formulated, so that after an oxygen lance is selected, the oxygen supply regime is determined by only formulating the reasonable oxygen lance operating regime, which comprises: determining proper oxygen supply intensity, determining oxygen supply pressure, determining reasonable gun positions and adjusting the gun positions in the converting process; adjusting the slag structure: in order to reduce the FeO content in the terminal slag, adopting a terminal gun-lowering and oxygen-lifting measure in actual production, reducing the terminal gun position from a normal converting gun position (oxygen gun scale zero position) to-100 mm, and simultaneously increasing the working oxygen pressure from 0.85MPa to 0.90-0.95 MPa; strictly controlling the primary pouring hit rate, adopting measures such as adding ore and cooling in the later period of the strictly forbidden converting, adopting a fine material policy to reduce the slag quantity, striving to improve the quality of the raw materials fed into the furnace on the basis of further perfecting the slag-leaving splash of the converter and the application of a slag operation process, adopting high-grade lime, adopting light-burned magnesium balls for slagging, reasonably adjusting the slag-forming material consumption according to the Si and S content conditions of molten iron, and properly reducing the lime quantity consumption under the condition of ensuring the production requirement; the silicon and manganese contents in the molten iron are low, desulfurization is not needed, the slag making mechanism and the dynamic characteristics are changed, because the lime consumption is reduced, the slag quantity is reduced, the slag alkalinity and the oxidation degree are increased, the occurrence of back drying is avoided, the physical properties and components of the slag are ensured to be beneficial to blowing operation, the furnace lining is not eroded, the slag splashing furnace protection requirement is met, if the slag alkalinity of the slag splashed by slag is too high, the magnesium oxide content reaches or exceeds the saturation value, the temperature of a hearth is reduced after pouring steel, magnesium oxide is crystallized and separated out, high-melting-point minerals C2S, C S are also separated out simultaneously and are concentrated at the bottom of the furnace and are combined with magnesia carbon brick periclase crystals at the bottom of the furnace to cause rising; temperature control in the smelting process: when the scrap steel is not matched in place, an iron cooling material can be used for adjusting the temperature, the scrap steel is added along with the head batch, the addition amount of the iron cooling material is not more than 800kg each time, and the over-splashing and the slag overflow are controlled; according to the requirements of molten iron conditions and slag end point components, various bulk materials are reasonably added, and when the process temperature is too high, on the premise of ensuring the requirements of the furnace burden end point components, iron cooling materials are used for cooling as much as possible, so that the slag is prevented from being excessively sticky; the feeding and cooling operation before tapping must be performed with point blowing, firstly, excessive feeding is avoided, and when the feeding floats on the surface of slag, the feeding cannot be thoroughly melted and the cooling effect cannot be truly achieved; secondly, the phenomenon that the slag is too thick when the slag is splashed due to the fact that the cooling material floats on the surface of the slag is avoided, a good slag splashing effect cannot be achieved, and meanwhile the furnace bottom is easy to rise; optimizing a slag splashing furnace protection process: the method combines with the field practice to study the slag splashing process, improves the operation process parameters, improves the working pressure of nitrogen slag splashing from original 0.70-0.90 MPa to 0.95-1.05 MPa, combines the conditions of slag temperature reduction, viscosity increase and the like in the slag splashing process, adjusts the slag splashing gun position from 700-1700 mm to 600-1400 mm, adjusts the distribution time of the slag splashing gun position, prolongs the proportion of slag splashing time of 50-500 mm at the low gun position and ensures that the minimum gun position time reaches 30S according to the characteristic that the proportion of medium-high carbon steel is high, and the problems of rising furnace bottom and corrosion loss of furnace caps are more prominent; the slag splashing gun position is reduced, the low gun position time is prolonged, the slag splashing effect is ensured, the slag which is not easy to splash and accumulated on the furnace bottom originally is effectively splashed and adhered on the furnace lining, particularly, the slag splashing effect on the furnace cap part is more ideal, the problems of rising of the furnace bottom and insufficient slag splashing capacity on the upper part of the furnace body are effectively solved, the slag splashing time proportion of the middle gun position is unchanged, the slag splashing requirement of the furnace lining at the trunnion part can be met, the slag splashing pressure and gun position are adjusted, the slag is uniformly coated on the furnace lining after slag splashing, and brick lining cannot be observed by naked eyes; the proper slag amount is ensured to influence the quality of slag splashing effect, the rising or not of the furnace bottom is directly influenced, the slag is too little, the temperature of the slag is reduced too fast by the injected nitrogen, the slag is caked and left at the furnace bottom when not splashed, the slag amount is too great, the temperature of the slag is reduced by the injected nitrogen in a certain time, and the slag cannot be thickened and adhered to the furnace wall; slag splashing protection and spray repair: the slag splashing effect is guaranteed to be a precondition that the furnace lining is reasonably maintained, the slag structure is required to be improved, physical properties and components of slag meet the slag splashing furnace protection requirement, the furnace lining is reasonably maintained by combining spray repair, the furnace repair times are reduced, the volume of the molten pool is not changed, molten metal in the molten pool is better participated in circulation as much as possible, a stagnation area is increased, and the possibility of the slag viscous furnace bottom is increased; the viscosity of the final slag is properly larger than that of the previous furnace with the large surface, the final slag cannot be too thin, after tapping of the previous furnace with the large surface, a converter worker shakes the furnace to enable the large furnace mouth of the converter to be downward, residual steel and residues in the furnace are dumped, and the furnace is shaken to a working position required by the furnace repairing; shaking the furnace to a scrap adding position, filling a repairing material into the furnace by using a scrap hopper, wherein the repairing material amount is generally 1-2 t, shaking the furnace back and forth, generally not less than 3 times, rotating at an angle of 5-60 degrees or a range of a furnace mouth shaking out of a smoke hood, and lowering a gun for baking; when obvious pits or partial pits appear on the facet and the steel tapping hole is higher than the furnace lining to cause incomplete steel production, the operation of repairing the facet is carried out, the repairing material is shaken to a pre-repairing position to be paved after entering the furnace, and after the steel tapping hole is not blocked by the repairing material, the requirement of repairing the facet is 1t repairing material less than 40min and 2t repairing material less than 50min; if the parts such as the furnace cap, the trunnion slag line and the like are sunken or fall off, a permanent layer is seen, gunning is carried out according to the situation, the gunning part is required to be smooth and has no obvious steps, the sintering time is ensured to be 5-10 min after gunning, and the gunning operation is carried out according to specific operation rules; accurately grasp the furnace bottom height: the furnace bottom and the gun position are measured every shift, the furnace bottom and the gun position are continuously eroded along with lining bricks for furnace repair, the radius of a molten pool is increased, in order to clearly show the erosion degree of the furnace lining and the rising condition of the furnace bottom, the furnace bottom and the gun position are measured every shift, the gun position of an oxygen gun is dynamically adjusted or the oxygen supply pressure is adjusted according to the erosion condition of the furnace lining and the rising condition of the furnace bottom, and the oxygen supply pressure is adjusted so that large splashing, furnace bottom erosion, furnace leakage and furnace bottom rising are avoided.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (4)

1. A method for controlling the rising operation of the converter bottom is characterized in that: the method for controlling the rising operation of the converter bottom comprises the following steps:

s1, optimizing a converter loading system: loading standard when each production condition is normal;

s2, optimizing an oxygen supply system: reasonable oxygen supply to the molten pool so as to obtain the optimal smelting condition, which is also called oxygen supply system in production, comprises two aspects: according to raw materials and tonnage of the furnace, a designed oxygen lance is designed; a reasonable oxygen lance operating regime is formulated, so that after an oxygen lance is selected, the oxygen supply regime is determined by only formulating the reasonable oxygen lance operating regime, which comprises: determining proper oxygen supply intensity, determining oxygen supply pressure, determining reasonable gun positions and adjusting the gun positions in the converting process;

s3, adjusting a slag structure:

(1) in order to reduce the FeO content in the terminal slag, adopting a terminal gun-lowering and oxygen-lifting measure in actual production, reducing the terminal gun position from a normal converting gun position (oxygen gun scale zero position) to-100 mm, and simultaneously increasing the working oxygen pressure from 0.85MPa to 0.90-0.95 MPa; strictly controlling the primary pouring hit rate, adopting measures such as adding ore and cooling in the later period of the strictly forbidden converting, adopting a fine material policy to reduce the slag quantity, striving to improve the quality of the raw materials fed into the furnace on the basis of further perfecting the slag-leaving splash of the converter and the application of a slag operation process, adopting high-grade lime, adopting light-burned magnesium balls for slagging, reasonably adjusting the slag-forming material consumption according to the Si and S content conditions of molten iron, and properly reducing the lime quantity consumption under the condition of ensuring the production requirement;

(2) the silicon and manganese contents in the molten iron are low, desulfurization is not needed, the slag making mechanism and the dynamic characteristics are changed, because the lime consumption is reduced, the slag quantity is reduced, the slag alkalinity and the oxidation degree are increased, the occurrence of back drying is avoided, the physical properties and components of the slag are ensured to be beneficial to blowing operation, the furnace lining is not eroded, the slag splashing furnace protection requirement is met, if the slag alkalinity of the slag splashed by slag is too high, the magnesium oxide content reaches or exceeds the saturation value, the temperature of a hearth is reduced after pouring steel, magnesium oxide is crystallized and separated out, high-melting-point minerals C2S, C S are also separated out simultaneously and are concentrated at the bottom of the furnace and are combined with magnesia carbon brick periclase crystals at the bottom of the furnace to cause rising;

s4, controlling the temperature in the smelting process:

(1) when the scrap steel is not matched in place, an iron cooling material can be used for adjusting the temperature, the scrap steel is added along with the head batch, the addition amount of the iron cooling material is not more than 800kg each time, and the over-splashing and the slag overflow are controlled;

(2) according to the requirements of molten iron conditions and slag end point components, various bulk materials are reasonably added, and when the process temperature is too high, on the premise of ensuring the requirements of the furnace burden end point components, iron cooling materials are used for cooling as much as possible, so that the slag is prevented from being excessively sticky;

(3) the feeding and cooling operation before tapping must be performed with point blowing, firstly, excessive feeding is avoided, and when the feeding floats on the surface of slag, the feeding cannot be thoroughly melted and the cooling effect cannot be truly achieved; secondly, the phenomenon that the slag is too thick when the slag is splashed due to the fact that the cooling material floats on the surface of the slag is avoided, a good slag splashing effect cannot be achieved, and meanwhile the furnace bottom is easy to rise;

s5, optimizing a slag splashing furnace protection process:

(1) the method combines with the field practice to study the slag splashing process, improves the operation process parameters, improves the working pressure of nitrogen slag splashing from original 0.70-0.90 MPa to 0.95-1.05 MPa, combines the conditions of slag temperature reduction, viscosity increase and the like in the slag splashing process, adjusts the slag splashing gun position from 700-1700 mm to 600-1400 mm, adjusts the distribution time of the slag splashing gun position, prolongs the proportion of slag splashing time of 50-500 mm at the low gun position and ensures that the minimum gun position time reaches 30S according to the characteristic that the proportion of medium-high carbon steel is high, and the problems of rising furnace bottom and corrosion loss of furnace caps are more prominent;

(2) the slag splashing gun position is reduced, the low gun position time is prolonged, the slag splashing effect is ensured, the slag which is not easy to splash and accumulated on the furnace bottom originally is effectively splashed and adhered on the furnace lining, particularly, the slag splashing effect on the furnace cap part is more ideal, the problems of rising of the furnace bottom and insufficient slag splashing capacity on the upper part of the furnace body are effectively solved, the slag splashing time proportion of the middle gun position is unchanged, the slag splashing requirement of the furnace lining at the trunnion part can be met, the slag splashing pressure and gun position are adjusted, the slag is uniformly coated on the furnace lining after slag splashing, and brick lining cannot be observed by naked eyes;

(3) the proper slag amount is ensured to influence the quality of slag splashing effect, the rising or not of the furnace bottom is directly influenced, the slag is too little, the temperature of the slag is reduced too fast by the injected nitrogen, the slag is caked and left at the furnace bottom when not splashed, the slag amount is too great, the temperature of the slag is reduced by the injected nitrogen in a certain time, and the slag cannot be thickened and adhered to the furnace wall;

s6, slag splashing furnace protection and spray repair: the slag splashing effect is guaranteed to be a precondition that the furnace lining is reasonably maintained, the slag structure is required to be improved, physical properties and components of slag meet the slag splashing furnace protection requirement, the furnace lining is reasonably maintained by combining spray repair, the furnace repair times are reduced, the volume of the molten pool is not changed, molten metal in the molten pool is better participated in circulation as much as possible, a stagnation area is increased, and the possibility of the slag viscous furnace bottom is increased;

s7, accurately grasping the furnace bottom height: the furnace bottom and the gun position are measured every shift, the furnace bottom and the gun position are continuously eroded along with lining bricks for furnace repair, the radius of a molten pool is increased, in order to clearly show the erosion degree of the furnace lining and the rising condition of the furnace bottom, the furnace bottom and the gun position are measured every shift, the gun position of an oxygen gun is dynamically adjusted or the oxygen supply pressure is adjusted according to the erosion condition of the furnace lining and the rising condition of the furnace bottom, and the oxygen supply pressure is adjusted so that large splashing, furnace bottom erosion, furnace leakage and furnace bottom rising are avoided.

2. A method for controlling a converter bottom up-draw operation according to claim 1, wherein: the optimized converter loading system is as follows:

(1) in the production process, the influence of the change of the molten iron condition on the heat of the converter is considered according to corresponding numerical values:

(2) every 0.10% of Si content of molten iron changes, and the terminal temperature is affected to 25 ℃;

(3) when the temperature of molten iron changes by 10 ℃, the end point temperature is affected by 7 ℃;

(4) when the molten iron condition changes to lead the end temperature to be reduced to be less than or equal to 55 ℃, the molten iron is filled in the converter without adjustment, slag retaining operation is adopted in the converter smelting process, and light burned magnesium balls replace light burned dolomite or iron block adding measures are taken to make up the heat which is lacking;

(5) when the molten iron condition changes to cause the end temperature to drop by more than 40 ℃, adopting measures of adjusting and loading to solve the problem of heat deficiency;

(6) the thermal effect of molten iron, scrap steel, pig iron, slag steel and smelting steel changes during integral filling;

(7) when the heat is deficient due to the change of the molten iron conditions, increasing 1 ton of molten iron and reducing 1 ton of scrap steel can increase the final temperature by 15 ℃ +15 ℃ =30 ℃;

(8) when the heat deficiency needs to be adjusted, the adjustment is performed according to the heat effect in the table 2 by increasing the molten iron amount and simultaneously reducing the scrap steel amount;

(9) the total loading amount of the converter is strictly controlled according to 128+/-1 ton, the proportion of molten iron and scrap steel is properly adjusted according to actual conditions, the total loading amount is ensured to be unchanged, and an assistant transmits the adjustment information to the converter length to correspondingly adjust, so that the stability of the loading amount of the converter for steelmaking is ensured.

3. A method for controlling a converter bottom up-draw operation according to claim 1, wherein: the optimized content of the oxygen supply system is as follows:

(1) oxygen supply intensity:

the oxygen supply intensity is the amount of oxygen in a standard state supplied to each ton of metal per unit time, that is: oxygen supply intensity (m) ³ /(t·min))=oxygen demand (m) per ton of metal ³ T)/time of supply (min);

(2) oxygen supply pressure:

the pressure of oxygen is an important parameter of oxygen supply operation in converter steelmaking, for the same oxygen lance, the oxygen supply strength can be increased by increasing the oxygen pressure, and the smelting time is shortened, but when the lance position is fixed, serious splashing can be caused by excessively increasing the oxygen pressure, meanwhile, the impact depth of oxygen jet flow on a molten pool can be increased, so that the danger of erosion of the bottom of the furnace exists, and the whole oxygen supply pressure of the converter is strictly controlled between 0.85 and 0.90 Mpa; gun position control: the method is characterized in that a variable-pressure gun-changing operation mode is adopted, a low-high-low three-section operation method is adopted in the whole gun position, fluctuation of the gun position in the blowing process cannot exceed 200mm each time, impact force of blowing reduction of a converter is increased aiming at the radius of a molten pool after furnace repair each time, and the situation that molten metal is correspondingly reduced is solved by adopting a Mach number reduction method, if the molten pool is sufficiently stirred, impact depth is required to be reduced, the molten metal at the bottom of the molten pool participates in circulation, and the viscous furnace bottom is increased;

(3) gun position and control thereof:

the four-hole Laval type oxygen lance is used for changing the form of the flow strand, because the included angle between the holes is unreasonable, a stagnation area is arranged at the center part of the bottom of the molten pool, molten metal in the stagnation area does not participate in circulation, the reduction of the stagnation area can be realized by increasing the included angle of spray holes, when normal converting is performed in standardized operation, the lance position is adjusted to 1350-1450 mm from the liquid level, when slag splashing is performed in 1200-1300 mm during carbon drawing, the lance position is adjusted to 1400mm from the bottom of the furnace before slag splashing, and then the lance position is gradually reduced to 600mm.

4. A method for controlling a converter bottom up-draw operation according to claim 1, wherein: the slag splashing protection and spray repair operation steps are as follows:

(1) and (3) supplementing:

the viscosity of the final slag is properly larger than that of the previous furnace with the large surface, the final slag cannot be too thin, after tapping of the previous furnace with the large surface, a converter worker shakes the furnace to enable the large furnace mouth of the converter to be downward, residual steel and residues in the furnace are dumped, and the furnace is shaken to a working position required by the furnace repairing;

(2) furnace bottom

Shaking the furnace to a scrap adding position, filling a repairing material into the furnace by using a scrap hopper, wherein the repairing material amount is generally 1-2 t, shaking the furnace back and forth, generally not less than 3 times, rotating at an angle of 5-60 degrees or a range of a furnace mouth shaking out of a smoke hood, and lowering a gun for baking;

(3) supplementing facets:

when obvious pits or partial pits appear on the facet and the steel tapping hole is higher than the furnace lining to cause incomplete steel production, the operation of repairing the facet is carried out, the repairing material is shaken to a pre-repairing position to be paved after entering the furnace, and after the steel tapping hole is not blocked by the repairing material, the requirement of repairing the facet is 1t repairing material less than 40min and 2t repairing material less than 50min;

(4) gunning up

If the parts such as the furnace cap, the trunnion slag line and the like are sunken or fall off, a permanent layer is seen, gunning is carried out according to the situation, the gunning part is required to be smooth and has no obvious steps, the sintering time is ensured to be 5-10 min after gunning, and the gunning operation is carried out according to specific operation rules.