JP2009203538A - Method for refining molten pig iron - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for desiliconizing or dephosphorizing a molten pig iron with the use of a container having a small free board such as a hot-metal ladle and a torpedo car, while inhibiting an outburst of slag, shortening the treatment period of time, and enhancing the productivity even without arranging a cylindrical body for securing the free board. <P>SOLUTION: This method for refining the molten pig iron includes: top-blowing and supplying a gaseous oxygen source from one supply system provided on a top-blow lance 7; at the same time, top-blowing and supplying at least one part of a solid oxygen source 4 from another supply system provided on the top-blow lance, onto the same place as a place to which the gaseous oxygen source has been supplied or the surface of a molten pig iron bath in the vicinity of the place, by using a carrier gas; and controlling the respective amounts of the oxygen sources to be supplied so that a ratio V/F<SB>O2</SB>(kg/Nm<SP>3</SP>) of a supply rate of the gaseous oxygen source F<SB>O2</SB>(Nm<SP>3</SP>/min×t) to a supply rate of the solid oxygen source V (kg/min×t) is in a range of 0.60 to 6.0, when desiliconizing or dephosphorizing the molten pig iron 2 housed in the hot-metal ladle 5 or the torpedo car by adding the oxygen source and a CaO-based flux 3 to the molten pig iron. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hot metal refining method in which a gaseous oxygen source and a solid oxygen source are supplied from a top blowing lance to hot metal contained in a small freeboard container such as a hot metal ladle or a kneading car. The gas oxygen source and the solid oxygen source supplied from the lance are supplied by separate supply systems, and the ratio of the gas oxygen source supply rate and the solid oxygen source supply rate is controlled within an optimum range, so that the slag The present invention relates to a refining method that suppresses jetting of iron to shorten the processing time and efficiently performs desiliconization or dephosphorization of hot metal.

  In recent years, desiliconization treatment or dephosphorization treatment (referred to as “hot metal preliminary treatment”) is performed in advance in the hot metal stage, and after removing a certain amount of silicon and phosphorus in the hot metal, the hot metal is charged into a converter and converted. Steelmaking methods that perform decarburization refining in a furnace have been developed. In this desiliconization treatment and dephosphorization treatment, an oxygen source such as oxygen gas and solid iron oxide and a CaO-based medium solvent were added to the hot metal, and silicon and phosphorus were oxidized with the oxygen source to control to an appropriate composition. This is done by incorporating silicon oxide or phosphorous oxide into the slag. A gaseous oxygen source containing oxygen such as oxygen gas or air is called a gaseous oxygen source, and a solid oxygen source containing iron oxide such as iron ore or scale is called a solid oxygen source.

  These desiliconization and dephosphorization processes are generally performed in a converter, a hot metal ladle (also referred to as a “blast furnace pan”), and a kneading car (also referred to as a “torpedo car”). Among these, the method using a converter has the advantage that the treatment can be completed in a short time because the free board is large and oxygen gas can be sprayed onto the molten iron at a high flow rate. However, in response to the recent increase in demand for steel materials, it is a fact that each steelworks has no room for existing converter capacity, and a large capital investment is required to increase the number of converters for hot metal pretreatment. Is required. On the other hand, the method using a hot metal ladle or a kneading car has the advantage that it can enjoy the advantages of hot metal pretreatment even if there is not enough room for the converter capacity because the process uses existing hot metal transfer containers and the equipment cost is low. Have.

  However, in the method using a hot metal ladle or a kneading car, since the free board is small, the generated slag is likely to be ejected from the container. For this reason, it is difficult to increase the oxygen source supply rate (referred to as “acid feed rate”). There is a problem that productivity is low. In view of this, several refining methods have been proposed that allow high-speed processing even in containers with a small free board such as a hot metal ladle or a kneading car.

  For example, in Patent Document 1 and Patent Document 2, when refining the hot metal by blowing a gaseous oxygen source and a solid oxygen source into the hot metal, a cylindrical body having a size surrounding the rising range of the bath surface of the blown gas, It has been proposed that the lower end of the slag is disposed so as to be in contact with the bath surface or immersed in the hot metal to prevent the slag formed by the cylindrical body from being ejected.

By arranging such a cylindrical body for securing a free board in the container, it becomes possible to treat the slag ejection without paying attention, but because the cylindrical body is installed, the refractory cost If the metal rises, or if metal or slag adheres or accumulates inside the cylindrical body, the production process will be hindered because work to remove them or replace the cylindrical body itself occurs. There is a problem.
JP 58-213812 A JP 61-104014 A

  The present invention has been made in view of the above circumstances, and the object of the present invention is to use a freeboard when performing desiliconization or dephosphorization of hot metal using a small freeboard container such as a hot metal pan or a kneading car. It is an object to provide a hot metal refining method capable of suppressing the slag jetting, shortening the processing time, and improving the productivity without arranging a cylindrical body or the like.

The hot metal refining method according to the first aspect of the present invention for solving the above-described problem is a desiliconization process or a desiliconization process for a hot metal by adding an oxygen source and a CaO-based solvent to the hot metal contained in a hot metal ladle or a kneading car. In performing the phosphorous treatment, a gaseous oxygen source is supplied from one supply system provided in the upper blowing lance to the hot metal bath surface, and at least a part of the oxygen supply is provided from another supply system provided in the upper blowing lance. The solid oxygen source is blown up using a carrier gas to the hot metal bath surface at or near the same location where the gaseous oxygen source is supplied, and the gaseous oxygen source supply rate F _O2 (Nm ³ / min · t) and the ratio V / F _O2 (kg / Nm ³ ) of the solid oxygen source supply rate V (kg / min · t) to be in the range of 0.60 to 6.0. , Each supply amount is controlled.

  In the hot metal refining method according to the second invention, in the first invention, the solid oxygen source is one or two of sintered ore, mill scale, dust and iron ore having a particle size of 1 mm or less. It is the above, It is characterized by the above.

  The hot metal dephosphorization method according to a third aspect of the present invention is the method according to the first or second aspect, wherein the solid oxygen source is supplied to the hot metal from the center hole of the top blowing lance, and the gaseous oxygen source is supplied to the periphery of the top blowing lance. The hot metal is supplied from the hole to the hot metal.

  According to the present invention, a small freeboard container such as a hot metal ladle or a kneading vehicle is used, and a hot oxygen degassing process or a dephosphorizing process is performed by blowing a gaseous oxygen source and a solid oxygen source on the molten metal accommodated in the container. In performing the above, the solid oxygen source is sprayed together with the carrier gas within the range of the addition rate appropriate to the addition rate of the gaseous oxygen source on the hot metal bath surface at or near the location where the gaseous oxygen source is supplied. Therefore, a gas escape route is formed in the generated slag, and the CO gas generated by reaction with FeO is discharged out of the system through this escape route, thereby reducing slag foaming and suppressing slag ejection. Is done. As a result, it is possible to improve the acid feed rate, and it is possible to shorten the refining time and improve the productivity. Further, since the hot spot and the temperature in the vicinity of the hot spot can be lowered, it is an advantageous condition for performing the dephosphorization treatment of the hot metal.

  The present invention will be specifically described below.

  The hot metal oxidation refining process using a relatively small freeboard transfer container such as a hot metal ladle or a kneading car as a reaction container, that is, desiliconization and dephosphorization of hot metal is generally performed using a gas such as oxygen gas. An element to be removed is oxidized by an oxygen source and a solid oxygen source such as iron ore, and the generated oxide is taken into a slag formed from a CaO-based medium solvent and removed. At this time, it is desirable to supply a gaseous oxygen source from the viewpoint of thermal margin, but there is a problem that the more the gaseous oxygen source is supplied, the easier the slag forming occurs. If the slag is ejected out of the reaction vessel due to slag forming and adheres to the track of the transport carriage, the carriage cannot be moved and production may be hindered. It was forced to decline. The gaseous oxygen source and the solid oxygen source are collectively referred to as an oxygen source.

  As a result of investigating and examining hot metal desiliconization treatment and dephosphorization treatment under various conditions, the present inventors have found that on the hot metal bath surface at or near the same location where the gaseous oxygen source is supplied, It has been found that the formation of slag is suppressed by supplying the solid oxygen source together with the carrier gas.

  Hereinafter, this phenomenon will be described in principle. The CO gas produced by the reaction between the oxygen source and the carbon in the hot metal is the cause of forming. Naturally, a large amount of CO gas is considered to be generated in the vicinity of the fire point where the gaseous oxygen source is blown and in the vicinity of the fire point. It is considered that the slag swells and forms when the CO gas generated at and near the fire point accumulates in the slag and cannot be discharged out of the system.

  When only the gaseous oxygen source is supplied from the top blowing lance, the hot spot and the slag near the hot spot are expected to be hot. Since the slag having a high temperature melts relatively uniformly, there is no gas escape route, and the generated CO gas is accumulated in the slag to cause a forming phenomenon. On the other hand, when the solid oxygen source is supplied at or near the supply location of the gaseous oxygen source, the solid oxygen source functions as a coolant because of its large decomposition endotherm, and the temperature of the slag near the fire point and the fire point Reduce. Due to the temperature drop of the slag, the slag does not become a uniform liquid phase, but a solid phase is deposited in part, and a gas escape passage is formed. Since the CO gas generated in large quantities near the fire point and near the fire point can escape from the system through the escape route, the gas does not accumulate in the slag, and slag forming is suppressed. In addition, since the reaction temperature near the fire point and the vicinity of the fire point is lowered, a condition advantageous in thermodynamics is created when performing the dephosphorization treatment.

After grasping the above phenomenon, the present inventors conducted further investigation and investigation. As a result, in order to suppress the formation of slag and at the same time obtain a smooth refining reaction, the supply rate F _O2 (Nm ³ / min · t) of the top blowing oxygen gas is the same as or the same as the supply location of the gaseous oxygen source. It has been found that there is an optimum range for the ratio V / F _O2 (kg / Nm ³ ) to the supply rate V (kg / min · t) of the solid oxygen source supplied in the vicinity.

That is, when the ratio V / F _O2 (kg / Nm ³ ) is smaller than 0.60, the supply rate of the solid oxygen source is too small with respect to the supply rate of the gaseous oxygen source. It was found that the slag cooling effect could not be sufficiently obtained and slag forming could not be suppressed. In this case, the acid delivery rate cannot be increased and the treatment time cannot be shortened. On the other hand, when the ratio V / F _O2 (kg / Nm ³ ) is greater than 6.0, the supply rate of the solid oxygen source is too large relative to the supply rate of the gaseous oxygen source. It was found that the slag liquid phase ratio was lowered by cooling too much, resulting in poor refining. Accordingly, the supply rate F _O2 (Nm ³ / min · t) of the top blown oxygen and the supply rate V (kg / min · t) of the solid oxygen source supplied at or near the supply location of the gaseous oxygen source The ratio V / F _O2 (kg / Nm ³ ) was found to be optimal in the range of 0.60 to 6.0.

The present invention has been made on the basis of these findings, and it is necessary to add a source of oxygen and a CaO-based medium solvent to hot metal contained in a hot metal ladle or a kneading car to perform desiliconization treatment or dephosphorization treatment on the hot metal. In addition, while supplying the gaseous oxygen source from one supply system provided in the upper blowing lance toward the hot metal bath surface, at least a part of the solid oxygen source is supplied from the other supply system provided in the upper blowing lance. The hot oxygen is supplied to the hot metal bath surface near or at the same location as the location where the gaseous oxygen source is supplied using a carrier gas, and the gaseous oxygen source supply rate F _O2 (Nm ³ / min · t ) And the supply rate V (kg / min · t) of the solid oxygen source, the respective supply amounts so that the ratio V / F _O2 (kg / Nm ³ ) is in the range of 0.60 to 6.0 It is characterized by controlling. The “hot metal bath surface in the vicinity of the place where the gaseous oxygen source is supplied” as used in the present invention means a portion near the fire point and having a temperature higher than the average temperature of the entire hot metal.

In hot metal desiliconization and dephosphorization, a CaO-based solvent is usually added to the hot metal. In particular, during the dephosphorization treatment, the slag formed by melting the CaO-based solvent traps the phosphor oxide formed by the reaction between the phosphorus in the hot metal and the supplied oxygen source in the slag. Since the dephosphorylation reaction proceeds, the addition of a CaO-based medium solvent is essential. During the desiliconization treatment, it plays a role of adjusting the basicity (CaO / SiO ₂ ) of the slag produced by the desiliconization reaction.

  In the present invention, the addition method of the CaO-based solvent need not be specified, and it may be added to the hot metal together with the conveying gas using an injection lance or a blowing nozzle, and placed on the hot metal bath surface from a chute or the like. It may be added, or it may be added by spraying onto the hot metal bath surface together with the carrier gas from the top blowing lance. Furthermore, a part may be added with an injection lance, and the rest may be added on top or added by top blowing. However, in the case where the CaO-based solvent is blown into the hot metal along with the carrier gas through the injection lance, the CaO-based solvent is heated by being blown into the hot metal, so that the hatching is promoted and the dephosphorization reaction is performed. Has the effect of promoting. In this case, since the CaO-based solvent is not directly added to the fire point and the vicinity thereof, the slag thickness at the fire point and the vicinity thereof is reduced, and the slag is added to the slag by the solid oxygen source added together with the carrier gas. Since a gas escape passage is easily formed, the generated CO gas is discharged out of the system through this escape passage, thereby further reducing the formation of slag and further suppressing the slag ejection.

  As the gaseous oxygen source used in the present invention, oxygen gas (including industrial pure oxygen), air, oxygen-enriched air, a mixed gas of oxygen gas and inert gas, and the like can be used. Usually, it is preferable to use oxygen gas because the reaction rate is faster than when other gases are used. When using a mixed gas, the oxygen concentration is preferably higher than that of air in order to ensure the reaction rate.

  The CaO-based solvent used in the present invention is not particularly limited as long as it contains CaO and can be refined as intended. Usually, it consists of CaO alone, or contains 50 mass% or more of CaO, and contains other components as necessary. As other components, hatching accelerators are generally used. As the hatching accelerator, a substance containing titanium oxide or aluminum oxide having an action of promoting the hatching by lowering the melting point of CaO can be mentioned, and these are preferably used. Fluorine-containing materials such as fluorite can also be used as hatching accelerators. However, when the slag is disposed of or the like, it is preferable not to use the fluorine-containing substance as a hatching accelerator from the viewpoint of protecting the environment by suppressing the amount of fluorine eluted from the slag. A substance in which fluorine is inevitably mixed as an impurity may be used. As a specific example of the CaO-based solvent, it is preferable to use quick lime or limestone because it is inexpensive. Further, light-burning dolomite or converter slag generated when decarburizing and refining in a converter can also be used as a CaO-based solvent.

  As the solid oxygen source used in the present invention, iron ore sintered ore, mill scale, dust (dust collection dust), iron sand, iron ore and the like can be used. Dust collection dust is dust containing iron that is recovered from exhaust gas in processes such as blast furnaces, converters, and sintering. From the viewpoint of increasing the reaction interface area of the solid oxygen source to increase the slag cooling efficiency and handling, the solid oxygen source is preferably a fine powder having a particle diameter of 1 mm or less. When the particle diameter exceeds 1 mm, not only the slag cooling effect due to the decomposition reaction of iron oxide is not obtained, but also there is a possibility of clogging in the conveying pipe. Here, the particle size of 1 mm or less means that the particle size passes through a sieving machine having an opening size of 1 mm. As long as the particle size passes through a sieving machine having an opening size of 1 mm, it is a spindle type whose major axis exceeds 1 mm. It does not matter. If the particle size is too fine, it may be sucked by the dust collection exhaust system and the yield may be lowered. Therefore, the particle size is preferably 1 μm or more.

  As a preferred embodiment of the present invention, the carrier gas for the solid oxygen source is any one of air, a non-oxidizing gas, a rare gas, a reducing gas, and a carbon dioxide gas that is a weak oxidizing gas close to the non-oxidizing gas. One or more gases are used. Here, the reducing gas is a hydrocarbon gas such as propane gas and CO gas, the non-oxidizing gas is a gas having no oxidizing ability such as nitrogen gas, and the rare gas is Ar gas or He gas. Inert gas such as.

  In the present invention, the effect can be obtained even if the carrier gas of the solid oxygen source is a gas containing a certain amount of oxygen such as air. However, some solid oxygen sources contain a small amount of metallic iron, which may burn in a pure oxygen stream and cause damage to equipment. Transporting the solid oxygen source with a transport gas having a lower oxygen concentration than air is also preferable from the industrial viewpoint of avoiding accidents.

  In the present invention, it is necessary to supply the solid oxygen source to the hot metal bath surface at or near the same location where the gaseous oxygen source is supplied, and also from the viewpoint of avoiding the complexity of incidental facilities. The supply system for the gaseous oxygen source and the supply system for the solid oxygen source are provided in the same upper blowing lance, although they are separate from each other. This can be achieved, for example, by making the upper blowing lance at least a double-pipe structure, with one being a flow path for a gaseous oxygen source and the other being a flow path for a solid oxygen source and a carrier gas. At this time, a gaseous oxygen source is supplied from a plurality of nozzle holes (referred to as “circumferential holes”) arranged concentrically around the center axis of the lance, and nozzle holes (“center hole”) arranged on the center axis of the lance. From the viewpoint of improving the yield of the solid oxygen source, the carrier gas and the solid oxygen source pass through the inside of the gaseous oxygen source and are sprayed on the hot metal. It is also preferable from the viewpoint that the solid oxygen source can surely reach the supply location of the gaseous oxygen source.

  In the present invention, it is not necessary to supply all of the solid oxygen source to be supplied to the hot metal bath surface at or near the same location where the gaseous oxygen source is supplied, and only a part of the solid oxygen source is gaseous oxygen. You may supply to the hot metal bath surface of the same place as the place where the source is supplied, or its vicinity. What is necessary is just to supply the solid oxygen source supplied to places other than the hot metal bath surface in the same place as the place where the gaseous oxygen source is supplied, or an appropriate method such as addition by blowing or blowing. In this case, in order to prevent the solid oxygen source from being sucked into the exhaust system, it is preferable to use a granular or lump of several mm to several tens mm.

  When a gaseous oxygen source is used, the hot metal temperature rises due to the oxidation reaction heat. On the other hand, when a solid oxygen source is used, the sensible heat, latent heat and decomposition heat of the solid oxygen source itself are oxidized reaction heat. Is larger than that, the hot metal temperature drops. Therefore, the use ratio of the gaseous oxygen source and the solid oxygen source is set according to the temperature before and after the hot metal treatment. That is, what is necessary is just to set from the hot metal temperature before a process, and the target hot metal temperature after a process. Moreover, in order to perform a refining reaction efficiently, it is preferable to stir the hot metal. Therefore, it is preferable to arrange an injection lance and a bottom blowing nozzle and blow a stirring gas into the hot metal.

  By performing the hot metal refining process in this manner, slag forming is reduced, and slag ejection from the container is achieved. By suppressing the ejection of slag, it is not necessary to reduce the supply rate of the gaseous oxygen source, and it is possible to increase the acid delivery rate. As a result, the processing time is shortened and the productivity is greatly improved.

  In the dephosphorization treatment facility shown in FIG. 1, the hot metal dephosphorization treatment was carried out under various operating conditions.

  In FIG. 1, a hot metal ladle 5 containing hot metal 2 is mounted on a carriage 6 and carried into a dephosphorization processing facility 1. The dephosphorization processing equipment 1 is provided with an upper blowing lance 7 and an injection lance 8 that can move up and down in the hot metal ladle 5. From the upper blowing lance 7, oxygen gas and a storage tank 10 are accommodated. The solid oxygen source 4 is sprayed onto the hot metal 2, and the CaO-based solvent 3 contained in the storage tank 9 is blown into the hot metal 2 from the injection lance 8.

  A tip portion of the upper blowing lance 7 is shown in FIG. As shown in FIG. 2, the upper blow lance 7 is composed of a cylindrical lance body 7a and a lance tip 7b connected to the lower end of the lance body 7a by welding or the like. Consists of four types of concentric steel pipes consisting of a pipe 17, an intermediate pipe 18, an inner pipe 19, and an innermost pipe 20, that is, a quadruple pipe. The tip of the copper lance tip 7b is centered on the lance center axis. A plurality of peripheral holes 16 that are arranged on concentric circles and face in a vertically oblique downward direction, and a center hole 15 that is arranged on the center axis of the lance are installed. The inclination θ between the peripheral hole 16 and the lance center axis is called an inclination angle.

  The gap between the outer pipe 17 and the middle pipe 18 and the gap between the middle pipe 18 and the inner pipe 19 form a flow path of cooling water for cooling the upper blowing lance 7. The gap with the pipe 20 serves as a supply flow path for oxygen gas to the peripheral hole 16, and the inside of the innermost pipe 20 has a solid oxygen source 4 to the center hole 15 and a carrier gas (here, nitrogen gas). Gas) supply flow path. That is, an oxygen gas supply system and a solid oxygen source 4 supply system are installed independently.

  The dephosphorization processing facility 1 is further provided with a raw material supply facility comprising a hopper 11, a raw material transfer device 12, and a chute 13, and solid oxygen contained in the hopper 11 using this raw material supply device. The source 4 can be added to the inside of the hot metal ladle 5 and added.

  The oxygen gas used is industrial pure oxygen, quick lime is used as the CaO-based medium solvent 3, dust collection dust in the sintering process is used as the solid oxygen source 4, and the CaO-based medium solvent 3 and the solid oxygen source 4 are used. Nitrogen gas was used as the carrier gas. In the figure, reference numeral 14 denotes a dephosphorizing slag formed from the CaO-based medium 3 or the like.

  The hot metal ladle 5 containing about 150 tons of hot metal 2 discharged from the blast furnace is transported to the dephosphorization treatment equipment 1 having the above-described configuration, and oxygen gas and a solid oxygen source 4 are sprayed onto the hot metal bath surface through the upper blowing lance 7. At the same time, the CaO-based solvent 3 was blown into the hot metal via the injection lance 8, and the dephosphorization treatment was performed while adding the solid oxygen source 4 accommodated in the hopper 11.

At that time, the supply rate F _O2 (Nm ³ / min · t) of oxygen gas from the top blowing lance 7 and the supply rate V (kg / min · t) of the solid oxygen source 4 from the top blowing lance 7 The ratio V / F _O2 (kg / Nm ³ ) was variously changed. For comparison, a dephosphorization method was also performed in which only oxygen gas was supplied from the top blowing lance 7 and all the solid oxygen source 4 was added from the hopper 11. In this case, the data was processed with the ratio V / F _O2 (kg / Nm ³ ) set to zero.

FIG. 3 shows the relationship between the ratio V / F _O2 (kg / Nm ³ ) and the dephosphorization time (min). When the ratio V / F _O2 (kg / Nm ³ ) is less than 0.60, the processing time becomes long. On the other hand, in the present invention example in which the ratio V / F _O2 (kg / Nm ³ ) is 0.60 or more, It was confirmed that the processing time was shortened.

FIG. 4 shows the relationship between the ratio V / F _O2 (kg / Nm ³ ) and the phosphorus concentration (mass%) in the hot metal after the dephosphorization treatment. When the ratio V / F _O2 (kg / Nm ³ ) exceeded 6.0, it was confirmed that the phosphorus concentration in the hot metal after the treatment was increased and the dephosphorization reaction was deteriorated. It was found that when the ratio V / F _O2 (kg / Nm ³ ) is 6.0 or less, the dephosphorization reaction is not inhibited.

From the results of FIG. 3 and FIG. 4 described above, it was found that the ratio V / F _O2 (kg / Nm ³ ) needs to be in the range of 0.60 to 6.0.

  FIG. 5 shows the relationship between the oxygen gas supply rate and the dephosphorization time. As is apparent from FIG. 5, in the example of the present invention, the oxygen gas supply rate can be maintained high, and the dephosphorization time is shortened. Thus, by applying the present invention, it is possible to suppress slag ejection and increase the acid delivery rate, and as a result, the treatment time can be shortened.

  In addition, although the said description was performed about the dephosphorization process of hot metal, the effect similar to the above can be acquired if the desiliconization process of hot metal is implemented using the apparatus similar to FIG.

It is the schematic of the dephosphorization processing equipment which implemented this invention. It is an enlarged view of the top blowing lance shown in FIG. It is a figure which shows the relationship between dephosphorization processing time and ratio V / F _O2 . It is a figure which shows the relationship between phosphorus concentration in hot metal after dephosphorization processing, and ratio V / F _O2 . It is a figure which compares and shows the dephosphorization processing time by the example of this invention, and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dephosphorization processing equipment 2 Hot metal 3 CaO type | system | group solvent 4 Solid oxygen source 5 Hot metal ladle 6 Bogie 7 Top blowing lance 7a Lance main body 7b Lance tip 8 Injection lance 9 Storage tank 10 Storage tank 11 Hopper 12 Raw material conveyance device 13 Chute 14 Desorption Phosphorus refining slag 15 Central hole 16 Circumferential hole 17 Outer pipe 18 Middle pipe 19 Inner pipe 20 Innermost pipe

Claims (3)

When adding an oxygen source and a CaO-based solvent to hot metal contained in a hot metal ladle or kneading car and applying desiliconization or dephosphorization to the hot metal, gaseous oxygen from one supply system provided in the top blowing lance A source is supplied by blowing upward toward the hot metal bath surface, and at least a part of the solid oxygen source from the other supply system provided in the upper blowing lance is the same place as the place where the gaseous oxygen source is supplied or The hot metal bath is blown up and supplied to the hot metal bath surface in the vicinity thereof, and the supply rate F _O2 (Nm ³ / min · t) of the gaseous oxygen source and the supply rate V (kg / min of the solid oxygen source) A method for refining hot metal, characterized in that each supply amount is controlled so that a ratio V / F _O2 (kg / Nm ³ ) to t) falls within a range of 0.60 to 6.0.   2. The hot metal removal according to claim 1, wherein the solid oxygen source is one or more of sintered ore having a particle size of 1 mm or less, mill scale, dust, and iron ore. Phosphorus treatment method.   3. The hot metal according to claim 1, wherein the solid oxygen source is supplied to the hot metal from a central hole of an upper blowing lance, and the gaseous oxygen source is supplied to the hot metal from a peripheral hole of the upper blowing lance. Refining method.

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