KR101346726B1 - Method for refining molten iron - Google Patents

Abstract

An upper lance for refining, having a main hole nozzle 11 and a sub hole nozzle 12 in a vertical downward or inclined direction at a lance tip, and a side portion of the lance at a position isolated upward from the tip. And a secondary combustion nozzle 13 in a horizontal or oblique downward direction, and inside the upper lance, a powder different from the solid oxygen source is supplied together with the oxygen-containing gas for blowing through the main hole nozzle; Or a first supply path for supplying an oxygen-containing gas for blowing through the main hole nozzle, a second supply path for supplying an oxygen-containing gas for secondary combustion through the secondary combustion nozzle; Having a third supply path for supplying a powder-like solid oxygen source together with a carrier gas through the hole hole, efficient oxidation refining is possible in oxidizing molten iron or molten steel. At the same time, it provides a phase lance for efficiently dissolving the attached skull of the converter type refining vessel.

Description

METHOD FOR REFINING MOLTEN IRON}

The present invention relates to a top lance for refining suitable for performing oxidation refining, such as dephosphorization treatment, to hot metal or molten steel in a converter type refining vessel. The present invention also relates to a method for refining molten iron using the phase lance. In the phase lance of the present invention, since the supply path of the oxygen containing gas and the supply path of the solid oxygen source such as iron oxide are separated, the oxygen-containing gas and the solid oxygen source are separated from these paths. It can be supplied independently to the molten iron in the converter type refining vessel or to the bath surface of molten steel. In addition, the phase lance of the present invention is capable of supplying powdery materials other than a solid oxygen source together with an oxygen-containing gas. In addition, the upper lance of the invention can supply the oxygen-containing gas for secondary combustion to the space in the furnace of the converter type refining vessel from the side of the lance separated from the lance tip.

In a steelmaking process using a blast furnace molten iron, molten iron is oxidized to remove most of the phosphorus (P) contained in the molten iron using oxygen gas or solid iron oxide before decarburizing blowing in the converter. Dephosphorization pretreatment is generally performed. In particular, in recent years, the quality demands required of steel products have become more stringent than before, and reduction of the phosphorus concentration more than ever has been required. In order to meet this quality demand, it is necessary to increase the molten iron amount which performs dephosphorization process more than before, and to stably lower the phosphorus concentration after dephosphorization process.

On the other hand, in order to respond to the request for the reduction of the impact on the environment represented by global warming these days, the reduction of slag emission in a steelmaking process becomes essential. In order to reduce the discharge amount of slag in the preliminary dephosphorization treatment of the molten iron, molten by an oxide (P ₂ O _5), that the slag (referred to as "for dephosphorization refining slag") functioning as a refiner (refining agent) for the absorption, deionized It is necessary to reduce the amount of the refining agent (hereinafter referred to as "refining agent for dephosphorization"). The main agent of the dephosphorizing refiner in the preliminary dephosphorization of molten iron is lime. Therefore, in order to meet the above quality requirements and to reduce slag emissions, a technique for maintaining the required dephosphorization amount while reducing the amount of lime used, that is, a technique for efficiently dephosphorizing with a small amount of lime is required.

In the preliminary dephosphorization treatment of molten iron, since lime which does not liquefy (slag) does not contribute to the dephosphorization reaction, in order to reduce the amount of lime used, it is important to promote the calcification of the added lime. . Conventionally, fluorite (fluorite: ore mainly composed of calcium fluoride) is known as a solvent for promoting sintering (fluxing agent: fluxing agent) excellent in sintering of slag and other slag, and fluorspar is also used for dephosphorization treatment. Has been. In recent years, however, with the tightening of environmental regulations, the use of fluorine-containing solvents has been restricted. Therefore, the means for promoting the dephosphorization reaction by lime even without using fluorite has been studied, and a number of proposals have been made.

As one of them, the technique of supplying the lime-based dephosphorization refiner to the same place or near the place where oxygen source, such as an oxygen containing gas and iron oxide, is supplied is proposed. This technique promotes sedimentation of the lime-based dephosphorizing refiner, and tries to dephosphorize efficiently with a little lime-based dephosphorizing refiner.

For example, Patent Literature 1 proposes a preliminary dephosphorization treatment method for molten iron, which is performed by adding a lime-based phosphorus refining agent and a heat absorbing substance to a place where oxygen gas is supplied. Patent Literature 2 discloses a phase lance suitable for adding a lime-based dephosphoring refiner to a fire spot (hot spot) region formed on a molten iron surface by supply of oxygen gas. The upper lance has a quadruple tube structure in which a powder blowing nozzle for supplying a lime-based dephosphorizing refining agent is disposed at an axial center portion, and a plurality of nozzles for supplying oxygen gas are arranged around it. have. In addition, Patent Literature 3 separates a supply path for supplying a lime-based phosphorus refining agent together with an oxygen-containing gas and a supply path for iron oxide, and from these paths, the oxygen-containing gas, the lime-based phosphorus refiner and iron oxide are used as molten iron baths. A phase lance for refining of a quintet tube structure has been proposed for supplying oxidative refining such as dephosphorization treatment to molten iron. This patent document 3 also proposes detecting the hole of a iron oxide supply path by providing a buffer space around an iron oxide supply path.

By the way, since the dephosphorization reaction in molten iron is more advantageous in temperature, the dephosphorization process is performed at the stage of molten iron | metal about 1300-1400 degreeC. For example, in patent document 1 and patent document 2, implementation temperature of less than 1300 degreeC-about 1350 degreeC is disclosed. Moreover, in recent years, since the free board (space other than the stationary hot metal which occupies in stationary hot metal) is large and steel stirring is possible, the preliminary dephosphorization process of molten iron | metal is a converter type. It is common to be done with a refining vessel. However, because of the low temperature, the molten iron scattered during the dephosphorization treatment adheres to and solidifies on the sidewall of the converter type refining vessel, the inlet to the furnace, and the scull is deposited, resulting in a decrease in the molten iron yield and the productivity of the scull removal operation. It was causing a drop.

This problem of scull adhesion is not limited to the preliminary dephosphorization treatment of molten iron, but is also a problem in decarburization and refining of molten iron in converters. That is, in decarburization and refining of the molten iron in the converter, the skull is deposited on the inner wall of the converter or the entrance of the furnace by scull scattering (called "spitting") or slag ejection (called "slopping") during the blowing. Problems arise, such as impedement of the molten iron into the furnace and the loading of iron scrap.

Many means for solving this scull adhesion are also proposed. For example, in patent document 4, the secondary combustion nozzle of a horizontal or downward direction is arrange | positioned at the side surface of the upper lance which has predetermined space | interval from the front end of the upper lance which has a main hole nozzle in the front end, and the said main hole A refinement method is proposed in which oxygen gas is supplied from a nozzle to oxidize molten iron or molten steel in the converter, and oxygen gas is supplied from the secondary combustion nozzle to dissolve the skull attached to the converter.

Japanese Laid-Open Patent Publication No. 2003-328021 Japanese Laid-Open Patent Publication No. 2006-336033 Japanese Laid-Open Patent Publication No. 2008-208407 Japanese Laid-Open Patent Publication No. 2008-138271

At present, in the steelmaking step, the preliminary dephosphorization treatment of molten iron is started, and as an oxygen source, oxidation of a gaseous oxygen source, such as an oxygen-containing gas, and a solid oxygen source, such as iron oxide, is combined and added to the same or adjacent points. Refining methods are mainstream. In addition, in that case, the said gaseous oxygen source is used as a conveying gas, and the flux, such as a dephosphorization refine | purifier, is conveyed with a gaseous oxygen source (refer patent document 3), and the flux is accordingly The refining method to put into an addition position is also performed. Moreover, even when such refining is carried out, dissolving the sculls attached to the inner wall of the converter type refining vessel and the inlet of the furnace by the gas oxygen source supplied from the secondary combustion nozzle on the upper lance side can reduce the iron yield and productivity. It is very important to secure.

As the phase lance for performing such refining, any phase lance cannot be employed if the conventional phase lance has been verified. Moreover, even if the said conventional phase lance is combined, it cannot become a satisfactory phase lance. For example, even if it connects to the oxygen-containing gas supply path of the phase lance proposed by patent document 3, and installs the nozzle for secondary combustion proposed by patent document 4, a flux is carried out with an oxygen-containing gas via an oxygen-containing gas supply path. When conveying, a problem arises that the nozzle for secondary combustion will block | close by this flux.

The present invention has been made in view of the above circumstances, and an object thereof is to achieve efficient oxidation and refining in oxidizing and refining molten iron or molten steel in a converter type refining vessel, such as preliminary dephosphorization of molten iron. It is to provide a phase lance for refining that can dissolve the skull attached to the mold refining vessel efficiently. An object of the present invention is also to provide a method for refining molten iron using the refining phase lance.

The gist of the present invention to solve the above problems is as follows.

(1) A refining phase lance for use in oxidation refining of molten iron or molten steel contained in a converter refining vessel, incorporating a main hole nozzle and a solid oxygen source for blowing in a vertical downward or oblique downward direction at the tip of the upper lance; It has a sub hole nozzle, and has a secondary combustion nozzle in a horizontal or obliquely downward direction at the side surface of the upper lance at a position isolated upward from the tip portion, and inside the upper lance, a solid A first supply path for supplying a powder different from an oxygen source together with the oxygen-containing gas for blowing through the main hole nozzle, or for supplying the oxygen-containing gas for blowing through the main hole nozzle; A second supply path for supplying an oxygen-containing gas through the secondary combustion nozzle and a solid oxygen source in a powder form together with a carrier gas through the sub-hole nozzle. A refining phase lance having a third supply path for feeding.

That is, the first supply path includes a refining flux inlet which introduces a powder different from the solid oxygen source (hereinafter also referred to as "refining flux") to the path, and an oxygen-containing gas for introducing the oxygen-containing gas into the path. Has an introduction. The refining flux inlet may be an inlet for introducing the refining flux together with the carrier gas, and the carrier gas is also preferably an oxygen-containing gas. Needless to say, the refining flux and the oxygen-containing gas are introduced from the same inlet (i.e., the pre-mixing of the refining flux and the oxygen-containing gas through the main hole nozzle is introduced from the inlet). It is good also as a structure. In operation, the introduction of the refining flux may be stopped, and only oxygen-containing gas may be introduced into the first supply path from the oxygen-containing gas introduction unit.

Moreover, the 2nd supply path has an oxygen containing gas introduction part which introduces an oxygen containing gas into the said path. The third supply path also has a solid oxygen source introduction portion for introducing a solid oxygen source into the path along with the carrier gas. In operation, the supply of the solid oxygen source may be stopped, and only the carrier gas may be introduced into the third supply path from the introduction portion.

Here, the first supply path and the second supply path may share the oxygen-containing gas introduction portion. In that case, it is supposed to provide a partition structure for preventing the refining flux from entering the second supply path.

(2) The end of the second supply path is blocked, so that the oxygen-containing gas supplied from the second supply path is configured not to join the first supply path and the third supply path, (1) Refining phase lance described in.

In addition, the distal end of a 2nd supply path means the part of the said path ahead of the secondary combustion nozzle which is closest to the lance front end (the lance front end side).

(3) The method described in (2) above, wherein the second supply path is configured to supply any one or two or more of a reducing gas, a carbon dioxide gas, a non-oxidizing gas, and a rare gas. Refining phase lance.

That is, the 2nd supply path has an introduction part which introduce | transduces any 1 type, or 2 or more types of gas in the said path. Needless to say, these gases may be introduced from the same introduction portion as the oxygen-containing gas.

(4) A buffer space in which any one or two or more of air, a reducing gas, a carbon dioxide gas, a non-oxidizing gas, and a rare gas exists in the vicinity of the third supply path is provided, and the gas exists in the buffer space. The phase lance for refining according to any one of (1) to (3) above, wherein the hole in the third supply path is detected based on a change in pressure or flow rate.

(5) The refining phase lance according to any one of (1) to (4), wherein the first supply path, the second supply path, and the third supply path are arranged on concentric circles.

(6) The lime-based dephosphorizing refiner is added to the molten iron contained in the converter refining vessel, and the added dephosphorizing refiner is sintered to form slag, and the oxidation refining of the molten iron is carried out in the above-mentioned (1) to ( Using the refining phase lance according to any one of 5), the oxygen gas for blowing is supplied to the molten iron bath surface from the first supply path, and the oxygen gas for drilling is supplied from the third supply path. Oxidation refining is supplied to the molten iron bath surface near the place where it is supplied together with the carrier gas, and the secondary combustion oxygen gas is supplied into the furnace space of the converter type refining vessel from the second supply path. , The method of refining the molten iron.

Moreover, it is preferable to supply at least one part of the said lime system dephosphorization refiner to the said molten iron from a 1st supply path | route.

According to the present invention, the phase lance is supplied with a powder different from a solid oxygen source, such as a lime-based dephosphorization refining agent, through a main hole nozzle together with an oxygen-containing gas for blowing, or oxygen for blowing. The first supply path for supplying the containing gas through the main hole nozzle, the second supply path for supplying the oxygen-containing gas for secondary combustion through the secondary combustion nozzle, and the solid oxygen source in the form of powder And a third supply path for supplying with the gas through the hole hole nozzle. Therefore, even when powder is supplied from the first supply path and the third supply path, only the oxygen-containing gas is injected from the secondary combustion nozzle, and the secondary combustion nozzle is stably maintained for a long time without being blocked. Inject oxygen-containing gas for secondary combustion. As a result, scull adhesion of the converter refining vessel is suppressed, and the detriment associated with scull adhesion is prevented in advance, thereby improving the iron yield and improving the productivity. In addition, since fluxes such as an oxygen-containing gas, a solid oxygen source, and a lime-based dephosphorization refining agent can be supplied to the same location or in the vicinity thereof, it is possible to efficiently carry out oxidation refining of molten iron and molten steel.

1 is a schematic cross-sectional view showing an example of a phase lance for refining according to the present invention.
2 is a view showing a supply path of a buffer gas to a buffer space in the refining phase lance according to the present invention.
3 is a schematic cross-sectional view showing another example of the refining phase lance according to the present invention.

(Mode for carrying out the invention)

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, although the lance illustrated below is a typical example, the shape, dimension, number, position, etc. of each site | part (nozzle, a path | route, etc.) are not limited to this. That is, in order to implement | achieve the objective of each site | part suitably, a structure can be designed according to a well-known technique according to a real use environment.

1 is a schematic cross-sectional view showing one example of a phase lance for refining according to the present invention. As shown in FIG. 1, the upper lance 1 which concerns on this invention is the lance nozzle 3 connected to the cylindrical lance main body 2 and the lower end of this lance main body 2 by welding etc. And a lance top portion 4 serving as an upper end portion of the lance main body 2, which is an introduction portion of the gas, powder, and cooling water (connection portion of the lance main body 2 with the respective supply facilities). The lance body 2 has a concentric circular shape of the outermost tube 5, the outer tube 6, the intermediate pipe 7, the partition tube 8, the inner tube 9, and the innermost tube 10. It consists of a species of steel pipe, or sextuple pipe. The copper lance nozzle 3 is provided with the subhole nozzle 12 of the perpendicular downward direction at the axial center part, and the several main hole nozzle which makes the discharge direction vertically obliquely downward around this subhole nozzle 12. (11) is provided. In addition, in the side part of the lance main body 2, the several secondary combustion nozzle 13 which makes a discharge direction horizontal or obliquely downward in the position isolated upward from the front end of the lance nozzle 3 is a lance main body. It is provided at substantially equal intervals in the circumferential direction of (2). In FIG. 1, although it is two steps in a perpendicular direction, you may be one step or three or more steps. Further, the provision of the secondary combustion nozzle 13 in the horizontal direction or obliquely downward direction at the side of the position separated upward from the distal end of the upper lance 1 indicates that the injection direction from the secondary combustion nozzle is It means to select the position and direction (angle) on the lance side part to face the furnace wall. In addition, the distance from the tip of the lance of the secondary combustion nozzle 13 closest to the lance tip is considered in consideration of design constraints such as cooling water passage in the general converter top lance nozzle 3. It is preferable to be 300 mm or more from the tip.

The main hole nozzle 11 is an oxygen-containing gas which is a blowing gas, or powders such as flux other than a solid oxygen source ("refining flux"), that is, the oxygen-containing gas as an oxygen-containing gas as a carrier gas. It is a nozzle for blowing powders, such as a refiner for accounting dephosphorization, into the inside of refining containers (not shown), such as a converter. The hole hole 12 is a nozzle for blowing solid oxygen sources such as iron ore and mill scale into the refining vessel together with the carrier gas. The secondary combustion nozzle 13 is a nozzle for blowing the oxygen-containing gas for secondary combustion into the internal space of the refining vessel. As shown in FIG. 1, the main nozzle 11 employ | adopts the shape of what is called a Laval nozzle in which a cross section expands so that it becomes a tip part. On the other hand, although the hollow hole nozzle 12 and the secondary combustion nozzle 13 are a straight shape, the hollow hole nozzle 12 and the secondary combustion nozzle 13 may also adopt the shape of a Laval nozzle. The upper lance 1 is supported by a support device (not shown) above the scouring vessel so as to be able to be lifted and lowered inside the scouring vessel.

In the case of the lance of FIG. 1, there are no restrictions such as the number of holes or the size of the holes provided in the main hole nozzle 11, but from the oxygen-containing gas supply amount required by the supply gas pressure to the upper lance 1. Inevitably, the number and aperture of the mounting holes are determined, and therefore, they are set within a range satisfying them. The secondary combustion nozzle 13 is also not particularly limited in the number and size of the mounting holes, but is set in an arrangement suitable for dissolution of the attached skull depending on the shape of the furnace. Here, the oxygen-containing gas is oxygen gas (oxygen gas), oxygen enriched air, mixed gas of oxygen gas and rare gas, and the concentration of oxygen gas is higher than that of air. As the solid oxygen source blown from the hole hole 12, sintered ore, mill scale, dust collecting dust, iron sand, iron ore, manganese ore and the like of iron ore can be used. Here, the dust collector is defined as the blast furnace, a converter, the dust containing, FeO or Fe ₂ O ₃ that is recovered from the exhaust gas in the sintering process.

In the present invention, flux such as quicklime, which is one kind of lime-based dephosphorization refining agent, blows oxygen-containing gas from the main hole nozzle 11 as a conveying gas, but similarly to the solid oxygen source from the sub-hole nozzle 12. In addition, you may blow flux, such as quicklime. Naturally, the flow rate ejected from the hole hole 12 and the flow rate ejected from the main hole nozzle 11 are each independently controlled by a separate flow meter (not shown).

A gap between the outermost tube 5 and the outer tube 6 and a gap between the outer tube 6 and the middle tube 7 serve as a flow path of cooling water for cooling the upper lance 1. The coolant supplied from a water supply pipe (not shown) installed in the lance government 4 passes through the gap between the exterior 6 and the heavy pipe 7 to reach the site of the lance nozzle 3, and the lance nozzle 3. Inverted at the portion of, it passes through a gap between the outermost tube 5 and the exterior 6 and is discharged from a drain pipe (not shown) installed in the lance government 4. The path of the water supply and drainage may be reversed.

The gap between the heavy pipe 7 and the partition pipe 8 serves as a second supply path for supplying the oxygen-containing gas to the secondary combustion nozzle 13. The oxygen-containing gas introduced into the inside of the heavy pipe 7 from the oxygen-containing gas supply pipe 14 communicating with the heavy pipe 7 installed in the lance government 4 passes through the second supply path and is secondary. It reaches | attains the combustion nozzle 13, and is made to eject from the secondary combustion nozzle 13. However, the upper end part of the partition tube 8 did not reach the installation site (introduction part of oxygen containing gas) of the oxygen containing gas supply pipe 14. That is, the oxygen-containing gas introduced into the inside of the heavy pipe 7 from the oxygen-containing gas supply pipe 14 is a gap between the partition tube 8 and the inner tube 9 (as will be described later) and the partition tube 8 and the inner tube. The gap with (9) also flows into the first supply path, and passes through the gap to be ejected to the main hole nozzle 11. In addition, the lower end part of the partition tube 8 did not reach to the site | part of the lance nozzle 3. That is, the oxygen-containing gas that has passed through the gap between the heavy pipe 7 and the partition pipe 8, that is, the second supply path, but is not ejected from the secondary combustion nozzle 13, joins the first supply path. Thus, the nozzle is ejected from the main hole nozzle 11.

The gap between the partition tube 8 and the inner tube 9 is an oxygen-containing gas for blowing, or a powder ("refining flux") different from solid oxygen together with the oxygen-containing gas, for example, lime-based degassing. It is a 1st supply path for supplying powders, such as a citric refiner, to the main hole nozzle 11. As shown in FIG. That is, in the lance part 4, the powder supply pipe 15 for supplying the refining flux as an oxygen-containing gas as the conveying gas (the installation site of the supply pipe becomes the flux introduction section for refining) is a partition tube 8 ), And as described above, an oxygen-containing gas supply pipe 14 (the installation site of the supply pipe becomes an oxygen-containing gas introduction portion) is provided in communication with the central pipe 7.

In the case where the refining flux is blown together with the blowing oxygen-containing gas from the main hole nozzle 11, the oxygen-containing gas supplied from the oxygen-containing gas supply pipe 14 and the powder and oxygen-containing gas supplied from the powder supply pipe 15. The gases are joined to pass through the first supply path. In this case, since the lower end position of the partition tube 8 is lower than the installation position of the secondary combustion nozzle 13, the powder which passes through the 1st supply path | route does not flow into the secondary combustion nozzle 13. . That is, the partition tube 8 functions as a partition structure for preventing the said refining flux from mixing in a 2nd supply path | route.

In the case where only the blowing oxygen-containing gas is blown from the main hole nozzle 11, the powder supply pipe 15 may be stopped or only the oxygen-containing gas may be supplied from the powder supply pipe 15.

As the refining flux, i.e., a powder different from the solid oxygen source, any known (or foreseeable) solid substance introduced for efficiently refining other than the solid oxygen source can be applied. For example, in addition to the above-mentioned lime-based dephosphorizing refining agent (quick lime (CaO), limestone (CaCO ₃ ), or dolomite (CaCO ₃ · MgCO ₃ ), decarburized slag, secondary refining slag, etc. Examples thereof include silica (SiO ₂ ), brick debris containing magnesium oxide, and the like, and sintering accelerators (including fluorite, titanium oxide, aluminum oxide, and the like), and the like. In general, at least a lime-based dephosphorizing refining agent is supplied as the refining flux.

The interior of the innermost tube 10 serves as a third supply path for supplying the solid oxygen source to the sub-hole nozzle 12 together with the carrier gas. That is, the solid oxygen source supplied to the inside of the innermost tube 10 with the conveying gas from the supply pipe (not shown) which communicates with the innermost tube 10 installed in the lance government 4 is the innermost tube 10. It passes through the inside of the nozzle hole 12, and it blows out from the hole hole 12. As shown in FIG. Here, the installation part (not shown) of the said supply pipe becomes a solid oxygen source introduction part. As a gas for conveyance which conveys a solid oxygen source, the gas whose oxygen content is less than air is suitable, It is especially preferable to use any 1 type, or 2 or more types of gas of air, a reducing gas, a carbon dioxide gas, a non-oxidizing gas, a rare gas. Do.

The reason for using air, a reducing gas, a carbon dioxide gas, a non-oxidizing gas, and a rare gas as a gas for conveyance of a solid oxygen source is as follows. Air has less oxygen gas content than the oxygen-containing gas blown from the main hole nozzle 11, and the reducing gas, the carbon dioxide gas, the non-oxidizing gas, and the rare gas do not substantially contain the oxygen gas. Therefore, it is possible to prevent the combustion during the conveyance of the trace amount of metallic iron contained in the solid oxygen source, and to prevent the flame generated by the contact between the solid oxygen source and the innermost tube 10 during the conveyance. Combustion of the innermost pipe 10 can be prevented. Here, the reducing gas is hydrocarbon gas and CO gas such as propane gas, and the non-oxidizing gas is gas having no oxidation capability such as nitrogen gas, and the rare gas is inert gas such as Ar gas or He gas. .

The gap between the inner tube 9 and the innermost tube 10 is sealed at a portion of the lance nozzle 3 at the distal end portion and becomes a dead end, and is supplied from the buffer gas supply pipe 16 provided in the lance part 4. It becomes a buffer space in which any 1 type, or 2 or more types of gas of air, a reducing gas, a carbon dioxide gas, a non-oxidizing gas, and a rare gas exist. In this invention, the gas which exists in a buffer space is called "buffer gas."

The supply path of the buffer gas to this buffer space is shown in FIG. As shown in FIG. 2, a detector 20, a remote control valve 21, a flexible hose 22, and a plurality of manual shut-off valves are provided in the buffer gas supply pipe 16 provided in the lance 4. The gas introduction device 19 for a buffer provided with 23 is connected. The buffer gas is supplied to the buffer space through the buffer gas introduction device 19. As the detector 20, a pressure gauge or a flowmeter, or both a pressure gauge and a flowmeter are provided. As a method of introducing the buffer gas into the buffer space, the remote control valve 21 may be shut off to seal the buffer gas in the buffer space, and the remote control valve 21 may be opened to open the buffer gas into the buffer space. Pressure may be applied at all times. In the example of FIG. 2, any operation is comprised. In addition, the flexible hose 22 is a margin when the upper lance 1 moves up and down. In addition, in the example of FIG. 2, although the detector 20 is provided in the side closer to the upper lance 1 than the flexible hose 22, you may install in the supply side rather than the flexible hose 22, and what site the detector 20 is It may be installed in. However, when detecting a hole based on the measured value of the pressure fluctuation of the buffer space, it is necessary to arrange the detector 20 on the side of the upper lance 1 rather than the remote control valve 21. Therefore, it is preferable to arrange | position the detector 20 on the side of the upper lance 1 rather than the remote control valve 21 from a viewpoint of the flexibility of operation.

The reason for using air, a reducing gas, a carbon dioxide gas, a non-oxidizing gas, and a rare gas as the buffer gas is the same as the reason for using these gas species as the carrier gas for the solid oxygen source. That is, even when a hole is generated in the innermost tube 10 which is the supply path of the solid oxygen source, that is, the third supply path by the return of the solid oxygen source, the buffer gas and the solid oxygen source are in contact with each other to buffer these gas species. This is because the combustion of the metal iron in the solid oxygen source and the combustion of the innermost pipe 10 due to the spark generated by the contact between the solid oxygen source and the innermost pipe 10 can be prevented as long as it is used as the gas. Therefore, in addition to the above, if the oxygen content is a gas of air or less, it can be used as a buffer gas.

Detection of the hole in the refining of the innermost tube 10 can be performed as follows. That is, when a pore occurs in the innermost tube 10 during refining, the buffer space and the interior of the innermost tube 10 communicate with each other so that the pressure in the buffer space changes or the flow rate of the buffer gas supplied to the buffer space changes. Therefore, the pore is detected based on the change. As a specific detection method, the following two methods can be employ | adopted. In one method, as a detector 20, a pressure gauge or both a pressure gauge and a flowmeter are provided, a buffer gas is introduced into a buffer space, and then the remote control valve 21 is shut off to provide a buffer gas to the buffer space. It is a method of enclosing and measuring the pressure in the buffer space during the refining by the detector 20, and detecting a pore. In another method, a flowmeter is provided as the detector 20, the remote control valve 21 is opened to move the pressure of the buffer gas at all times in the buffer space, and the flow rate is measured by the detector 20 in this state. It is a method of detecting a hole from the flow rate change in one case.

Hereinafter, the example which performs preliminary dephosphorization of molten iron | metal in a converter using the phase lance 1 which concerns on this invention comprised in this way is demonstrated.

The upper lance 1 according to the present invention is disposed at a predetermined position above the molten iron in the converter, and oxygen gas is blown from the main hole nozzle 11 as the oxygen-containing gas toward the molten iron bath surface. At the same time, any one or two or more gases of air, reducing gas, carbon dioxide gas, non-oxidizing gas, and rare gas are blown from the hollow hole nozzle 12 as a carrier gas toward the molten iron bath surface. The solid oxygen source blown out from the hole hole 12 is supplied to or near the molten iron bath surface at the same place where the oxygen gas is supplied. In the dephosphorization treatment, a slag for dephosphorization refining for absorbing phosphorus oxide (P ₂ O ₅ ) generated by the dephosphorization reaction is required, and a lime-based dephosphorizing refiner, which becomes this dephosphorization refining slag, is added.

There is no restriction | limiting in particular in content of CaO as long as it contains CaO and can carry out the dephosphorization treatment which this design intends as a lime-based dephosphorization refiner. Usually, it consists of CaO alone, or contains 50 mass% or more of CaO, and contains other components as needed. As a specific example, quicklime (CaO), limestone (CaCO ₃ ), or dolomite (CaCO ₃ · MgCO ₃ ) can be used, and a substance containing titanium oxide, aluminum oxide, and magnesium oxide as an sintering accelerator in these materials. It is also possible to use a mixture of these. In addition, decarburization slag, ladle refining slag, and the like also contain CaO as a main component and have a low phosphorus content, and thus can be sufficiently used as a lime-based dephosphorizer.

In the molten iron bath surface, the place where oxygen gas collides with the molten iron bath surface (called a "flaming point") has a high temperature due to the reaction of oxygen gas with carbon in the molten iron, and is a solid oxygen source supplied near the firing point or the firing point. Is melted quickly, increasing the FeO component in the slag. As a result, the oxygen potential of the slag rises, that is, the slag optimum for the dephosphorization reaction is quickly formed, and the dephosphorization treatment can be performed even at a small slag amount or at a high temperature. Further, by introducing the lime-based dephosphorizing refiner into the vicinity of a fire or a fire, the sedimentation of the lime-based dephosphorizing refiner is promoted, and the dephosphorization refining slag is formed early, and the dephosphorization reaction is further promoted. Therefore, it is preferable to inject the lime-based dephosphorizing refiner into the vicinity of the fire point or the fire point through the main hole nozzle 11 or the main hole nozzle 11 and the sub hole nozzle 12.

At this blow, oxygen gas for secondary combustion is supplied from the secondary combustion nozzle 13 to dissolve the adhesion skull of the furnace body in parallel with dephosphorization refining or to prevent the adhesion of the skull. As a result, the detriment associated with scull adhesion is prevented in advance, so that the iron yield and the productivity are improved.

Supply (Q) of the oxygen gas from the case, the second nozzle (13) for primary combustion is preferably in the range of 5 to 30% of the oxygen gas supply amount (Q _O) critical path from the nozzle 11. 100Q / the Q _O is less than 5%, the oxygen gas is too small for the secondary combustion, and secondary combustion heating value is low, it is not possible to dissolve the skull attachment. On the other hand, if the 100Q / Q _O exceeds 30%, the secondary combustion exothermic heat is excessive, the melting (erosion) of the refractory furnace body is promoted.

In addition, when the flow rate of the oxygen gas from the secondary combustion nozzle 13 becomes too fast, and the oxygen gas from the secondary combustion nozzle 13 directly reaches the furnace wall, not only the attached skull dissolves locally, Roche refractories are locally dissolved. Therefore, in the period until the oxygen gas fractionation from the secondary combustion nozzle 13 reaches the furnace wall, the oxygen gas fractionation is reacted with CO gas generated in the furnace to uniformly disperse the secondary combustion heat into the furnace. It is important.

As disclosed in Patent Document 4, when the flow rate of the oxygen gas from the secondary combustion nozzle 13 is attenuated to 30 m / sec, the in-house generated CO gas and the oxygen gas from the secondary combustion nozzle 13 Is reacted, and it is known that a secondary combustion reaction occurs. The distance (X (m)) from the nozzle outlet of the secondary combustion nozzle 13, in which the flow rate of oxygen gas supplied from the secondary combustion nozzle 13 becomes 30 m / sec, is expressed by the following equation (1). Is given.

However, in formula (1), V ₀ : flow rate of oxygen gas jet (m / sec) at the outlet of the secondary combustion nozzle, de: outlet diameter of the secondary combustion nozzle (mm) ), C = 0.016 + 0.19 / (P ₀ -P _e ), P ₀ : oxygen back pressure (kgf / cm 2) of absolute pressure indication of secondary combustion nozzle, P _e : atmospheric pressure of absolute pressure indication in converter type refining vessel (kgf / cm 2).

If the distance X does not reach the furnace wall, the design of the phase lance and the control of the blowing conditions can be avoided, so that local skull melting and melting of the furnace wall refractory can be avoided, and the secondary combustion reaction heat is transferred into the furnace. It can disperse uniformly.

In addition, in the upper lance 1 shown in FIG. 1, the lower end part of the partition tube 8 does not reach the site | part of the lance nozzle 3, and the 2nd supply path is opened in the 1st supply path. For this reason, the flow rate of the oxygen-containing gas blown out from the secondary combustion nozzle 13 depends on the ratio between the total cross-sectional area of the main hole nozzle 11 and the total cross-sectional area of the secondary combustion nozzle 13, and thus the secondary flow rate. The ejection amount from the combustion nozzle 13 cannot be controlled independently. That is, the total amount of the oxygen-containing gas supplied from the oxygen-containing gas supply pipe 14 and the powder supply pipe 15 is distributed according to the ratio of the total cross-sectional areas of both. In order to improve this and to carry out high precision blow control, you may make it control independently the flow rate of the oxygen containing gas for secondary combustion. In this case, however, it is necessary to replace the internal structure of the phase lance with the phase lance 1 shown in FIG.

3, the example of the phase lance which can control the flow volume of the oxygen containing gas for secondary combustion independently of the blowing oxygen containing gas is shown.

In the upper lance 1A shown in FIG. 3, the lower end of the partition tube 8 reaches to the site of the lance nozzle 3, and at the site of the lance nozzle 3, the heavy pipe 7 and the partition pipe 8 are separated from each other. In other words, the second supply path is sealed. In addition, in the lance part 4, the upper end of the partition tube 8 is located above the upper end position of the middle tube 7, and the sealing material for sealing is provided between the middle tube 7 and the partition tube 8. And the second supply path is sealed. The oxygen-containing gas supply pipe 18 communicates with the middle pipe 7 (the installation portion of the supply pipe becomes the oxygen-containing gas introduction portion). That is, the oxygen-containing gas supplied from the oxygen-containing gas supply pipe 18 to the inside of the heavy pipe 7 passes through the gap between the heavy pipe 7 and the partition pipe 8, that is, the second supply path, and is used for secondary combustion. It ejects from the nozzle 13.

On the other hand, in the lance part 4, the oxygen-containing gas and powder supply pipe 17 communicate with the partition tube 8 (the installation part of this supply pipe becomes a refinery flux introduction part and oxygen-containing gas introduction part). Then, the oxygen-containing gas for blowing supplied from the oxygen-containing gas / powder supply pipe 17 into the partition tube 8 or the refining flux using the oxygen-containing gas as the conveying gas is the partition tube 8. It passes through the clearance gap with the inner pipe 9, ie, a 1st supply path | route, and blows out from the main-hole nozzle 11. When only the oxygen-containing gas is blown from the main hole nozzle 11, only the oxygen-containing gas is supplied from the oxygen-containing gas / powder supply pipe 17, and the powder containing the oxygen-containing gas as the conveying gas is blown from the main hole nozzle 11. In this case, the powder is supplied from the oxygen-containing gas and powder supply pipe 17 together with the oxygen-containing gas. The other structure of the upper lance 1A has the same structure as the upper lance 1 shown in FIG. 1, the same part is represented by the same code | symbol, and the description is abbreviate | omitted. The preliminary dephosphorization treatment of the molten iron using the phase lance 1A may also be performed in accordance with the case where the phase lance 1 is used.

In addition, depending on the situation of blowing, it may not be necessary to blow out oxygen gas from the secondary combustion nozzle 13 via a 2nd supply path. In this case, in the phase lance 1A shown in FIG. 3, in order to prevent the blockage of the secondary combustion nozzle 13, any one of reducing gas, carbon dioxide gas, non-oxidizing gas, and rare gas from the second supply path or It is comprised so that 2 or more types of gas can be supplied.

As described above, according to the present invention, the upper lances 1 and 1A have a main powder nozzle 11 having a powder different from a solid oxygen source such as a lime dephosphorizing refiner together with an oxygen-containing gas for blowing. Or a first supply path for supplying an oxygen-containing gas for blowing through the main hole nozzle 11 and an oxygen-containing gas for secondary combustion through the secondary combustion nozzle 13. And a third supply path for supplying the solid oxygen source in the form of powder together with the carrier gas through the sub-hole nozzle 12, so that powder is removed from the first supply path and the third supply path. Even if supplied, only the oxygen-containing gas is injected from the secondary combustion nozzle 13, and the secondary combustion nozzle 13 injects the secondary combustion oxygen-containing gas stably over a long period of time without being blocked. . Thereby, scull adhesion of the converter refining container is suppressed, and the damage accompanying scull adhesion is prevented beforehand.

[Example]

Example 1

The molten iron from the blast furnace is desiliconized into a blast furnace casthouse, if necessary, and then returned to a 300-ton converter, which is then preliminarily removed four times using the phase lance shown in FIG. The process was performed (Invention Examples 1-4). In addition, four hole nozzles were made into the uniform arrangement on concentric circles. In addition, the secondary combustion nozzles are arranged on the circumference in eight equally up and down directions, and the angle (θ (°)) between the secondary combustion nozzle and the upper lance is determined by the oxygen fractionation from the secondary combustion nozzle. The distance (X (m)) from the nozzle outlet of the secondary combustion nozzle 13, which has a flow rate of 30 m / second, was made to satisfy the following formula (2).

Here, X is the distance m from the nozzle outlet of the secondary combustion nozzle determined from the formula (1), and H is the distance m in the horizontal direction from the center of the phase lance to the converter wall. Incidentally, the angle θ is an angle formed by the center line of the secondary combustion nozzle and the center line of the phase lance, and the vertical direction is set as a reference (= 0 °) (0 ° <θ ≦ 90 °). Therefore, Xsin (theta) has shown the fractionation reach | attainment distance m of the horizontal direction from the nozzle for secondary combustion.

The phosphorus concentration of the molten iron before the dephosphorization was unified to 0.12 mass%, and the phosphorus concentration of the molten iron after the dephosphorization was aimed at 0.020 mass% or more. The iron yield (η) is the mass of the molten iron that has been removed after dephosphorization treatment with respect to the total mass (W ₀ + W _S ) between the mass (W ₀ ) of the molten iron charged into the converter and the mass (W _S ) of the iron scrap. (W) shown by the percentage _{(η = 100W / (W O} + W S)) is a value.

In the dephosphorization treatment, oxygen gas is supplied from the oxygen-containing gas supply pipe 14, oxygen oxide gas is supplied from the powder supply pipe 15 as a gas for transport, and quicklime powder (average particle diameter of 1 mm or less) is supplied to the third inner tube. Nitrogen gas was supplied from the supply path as a solid gas source of powder as a conveying gas. In this case, the first supply path is a supply path of oxygen gas and quicklime powder, and the second supply path is a supply path of oxygen gas.

Apart from the phase lance, the lump shaped quicklime was also introduced into the furnace from the hopper installed on the furnace (the amount of quicklime from the top lance: the amount of quicklime from the furnace phase hopper = 8: 2). However, a de-cited refiner, fluorine compounds such as CaF ₂ was treated without the use of dephosphorization. In addition, nitrogen gas was blown from the tuyeres at the bottom of the furnace as a stirring gas at a flow rate of 0.03 to 0.30 Nm 3 / min per ton of molten iron.

The oxygen gas flow rate supplied from the main hole nozzle and the secondary combustion nozzle was 0.6 to 2.5 Nm 3 / min per ton of molten iron. The unit consumption of oxygen gas was 12 Nm <3> / t except the oxygen gas required for desulfurization. Oxygen gas flow rate (Q) from a nozzle for secondary combustion of the oxygen gas flow rate (Q _O) of the critical path from the nozzle, that is, 100Q / Q _O was 6%. Examples of the solid oxygen source include any one of powdery iron ore (average particle size of 50 µm), iron sand (average particle size of 100 µm), mill scale (average particle size of 500 µm), and sintered ore of iron ore (average particle size of 100 µm). Was attached from the hole hole nozzle.

The presence or absence of the pore in the innermost tube and the inner tube was monitored by a method of detecting the change in the gas flow rate for buffering, but no special pore occurred.

Moreover, as a comparative example, the dephosphorization process which did not supply the oxygen combustion gas of secondary combustion to the inside space of the furnace and mechanically closed the nozzle of the phase lance shown in FIG. 1 was also performed (comparative example 1). Other dephosphorization treatment conditions of a comparative example were performed according to the example of this invention. In Table 1, the molten iron component and operating conditions before and after the dephosphorization treatment in this invention example and a comparative example are shown. CaO raw unit and solid oxygen source usage-amount in Table 1 are quantity per ton of molten iron | metal.

As shown in Table 1, in all the examples of the invention in which a solid oxygen source was supplied near the mounting surface of the oxygen gas from the phase lance, the phosphorus concentration in the molten iron after the dephosphorization treatment was 0.020% by mass or less, and iron The yield was 98% or more. In contrast, in Comparative Example 1, the phosphorus concentration in the molten iron after the dephosphorization was 0.020% by mass or less, but the iron yield was less than 98%. That is, the loss of the molten iron in the dephosphorization treatment was 1.2 to 1.7% in the example of the present invention relative to 2.1% of the comparative example, and was remarkably improved.

[Example 2]

After degreasing the molten iron out of the blast furnace into the blast furnace column, if necessary, it is returned to the converter having a capacity of 300 tons, and the preliminary dephosphorization treatment is performed twice in total using the phase lance shown in FIG. Honor 5-6).

As a result of constant control of the oxygen gas flow rate from the secondary combustion nozzle during the dephosphorization treatment, the oxygen gas flow rate Q from the secondary combustion nozzle to the oxygen gas flow rate Q _O from the main hole nozzle, 100Q / Q _O was 12%. Also in this case, it was confirmed that Xsinθ was in a range satisfying the formula (2). Other dephosphorization treatment conditions were made into the same conditions as Example 1. Table 2 shows molten iron components and operating conditions before and after the dephosphorization treatment. The CaO raw unit and solid oxygen source used in Table 2 are the quantity per ton of molten iron | metal, and the definition of iron yield is the same as that of Example 1.

As shown in Table 2, since the oxygen gas flow rate from the secondary combustion nozzle increased in comparison with Example 1, the secondary combustion calorific value increased, skull adhesion was further suppressed, and the iron yield in the dephosphorization treatment. Silver was almost 99% (that is, molten iron loss was almost 1%), and it was confirmed that the higher was obtained.

[Example 3]

After degreasing the molten iron from the blast furnace to the blast furnace column, if necessary, it is returned to the 350-ton capacity converter and preliminary dephosphorization treatment is performed using the phase lances shown in Figs. Honor 7-8).

Oxygen gas was blown from the tuyeres at the bottom of the furnace as a gas for stirring at a flow rate of 0.3 Nm 3 / min per ton of molten iron. The blower at the bottom of the furnace had a double pipe structure, and oxygen gas was blown from the inner tube and propane gas was blown from the outer tube as the cooling gas according to the flow rate of the oxygen gas. As a solid oxygen source, 6 kg of sintered ore (average particle size 100 micrometers) of iron ore was used per 6 ton of molten iron, and it mounted from the upper lance nozzle. The conditions of oxygen fractionation from a secondary combustion nozzle were made into the range which satisfy | fills said Formula (2). Other dephosphorization treatment conditions were made into the same conditions as Example 1.

In addition, as a comparative example, the secondary combustion nozzle of the phase lance shown in FIG. 1 was mechanically blocked, and the dephosphorization process which does not supply the oxygen gas for secondary combustion to the furnace space was also performed (comparative example 2). Other dephosphorization treatment conditions of a comparative example were performed according to the example of this invention.

Table 3 shows molten iron components and operating conditions before and after the dephosphorization treatment. The oxygen gas flow rate Q from the secondary combustion nozzle to the oxygen gas flow rate Q _O from the main hole nozzle during the dephosphorization treatment, that is, 100 Q / Q _O, was also shown. CaO raw unit in Table 3 is the quantity per ton of molten iron | metal, and definition of iron yield is the same as that of Example 1.

As shown in Table 3, even in the steel stirring condition in which oxygen gas is blown from the bottom blow tuyeres, sclerosis is further suppressed by the increase in the secondary combustion calorific value, and the iron yield in the dephosphorization treatment is increased. I could confirm that I became more senior.

Example 4

The molten iron drawn out from the blast furnace was conveyed to a converter having a capacity of 300 tons, and decarburization dephosphorization treatment was performed using the phase lance shown in FIG. In decarburization and refining of molten iron | metal, a dephosphorization reaction also arises in parallel by raising the basicity of the slag in the furnace to produce | generate.

In the decarburization dephosphorization treatment, oxygen gas is supplied from the oxygen-containing gas supply pipe 18, oxygen oxide gas is supplied from the oxygen-containing gas and powder supply pipe 17 as a conveying gas, and quicklime powder (average particle diameter 1 mm or less) is supplied to the innermost pipe. Argon gas was supplied as a conveying gas from the 3rd supply path which is inside of the solid oxygen source of powder.

Apart from the phase lance, lump shaped quicklime was also introduced into the furnace from the hopper installed on the converter furnace. However, decarbonation dephosphorization treatment was carried out without using a fluorine compound such as CaF ₂ as a refining agent. In addition, argon gas was blown in from the tuyeres at the bottom of the converter as a gas for stirring at a flow rate of 0.15 Nm 3 / min per ton of molten iron.

The oxygen gas flow rate supplied from the main hole nozzle was 3.2 Nm3 / min per ton of molten iron. From the nozzle for secondary combustion, oxygen gas was supplied in the first half of the time from the start of blowing to completion, and Ar gas was supplied in the second half. The oxygen gas flow rate Q from the secondary combustion nozzle with respect to the oxygen gas flow rate Q _O from the main hole nozzle was 5%. It was confirmed that the condition of oxygen fractionation from the secondary combustion nozzle was in a range satisfying the above formula (2). As a solid oxygen source, 6 kg per ton of molten iron was used for sintered ore (average particle size of 100 micrometers) of iron ore, and it was blow-off from the hole nozzle.

Moreover, as a comparative example, the dephosphorization process which does not supply the oxygen gas for secondary combustion to the in-furnace space by mechanically blocking the nozzle for secondary combustion of the phase lance shown in FIG. 3 was also performed (comparative example 3). Other decarburization dephosphorization treatment conditions of a comparative example were performed according to the example of this invention.

In Table 4, the molten iron component and operating conditions before and after the dephosphorization treatment in an example of this invention and a comparative example are shown. CaO raw unit and solid oxygen source usage-amount in Table 4 are the quantity per 1 ton of molten iron | metal. Iron yield (η) is the mass (W ₀ ) of the molten steel that was tapped after the decarburization dephosphorization treatment with respect to the total mass (W ₀ + W _S ) between the mass (W ₀ ) of the molten iron charged into the converter and the mass (W _S ) of the iron scrap. _I ) is expressed as a percentage (η = 100W _I / (W ₀ + W _S )).

As shown in Table 4, the iron yield of Inventive Example 9 was slightly superior to Comparative Example 3. That is, even if there are few conditions of a scull adhesion as a high temperature process, a yield can be improved by using secondary combustion partially.

According to the present invention, even when the powder is supplied from the first supply path and the third supply path, only the oxygen-containing gas is injected from the secondary combustion nozzle, and the secondary combustion nozzle is not blocked. The oxygen-containing gas for secondary combustion is injected stably over a long period of time. As a result, scull adhesion of the converter type refining vessel is suppressed, and the detriment associated with scull adhesion is prevented in advance, thereby improving the iron yield and improving the productivity. In addition, since fluxes such as an oxygen-containing gas, a solid oxygen source, and a lime-based dephosphorization refining agent can be supplied to the same location or in the vicinity thereof, it is possible to efficiently carry out oxidation refining of molten iron and molten steel.

1: phase lance
1A: Sang Lance
2: lance body
3: lance nozzle
4: lance government
5: outermost view
6: appearance
7: Zhongguan
8: partition tube
9: inner tube
10: Choi Ingwan
11: hole nozzle
12: hole hole nozzle
13: nozzle for secondary combustion
14: oxygen-containing gas supply pipe
15: powder supply pipe
16: buffer gas supply pipe
17: oxygen-containing gas and powder supply pipe
18: oxygen-containing gas supply pipe
19: gas introduction device for the buffer
20: detector
21: remote control valve
22: flexible hose
23: manual shut off valve

Claims (10)

In the lime-based dephosphorizing refiner is added to the molten iron contained in the converter type refining vessel, the added dephosphorizing refiner is made into slag by oxidizing the added dephosphorizing refiner, and the oxidation refining of the molten iron is carried out.
A top lance for refining used for oxidation refining of molten iron or molten steel contained in a converter type refining vessel,
At the tip of the upper lance, there is a main hole nozzle for blowing in a vertical downward or oblique downward direction and a sub hole nozzle for blowing solid oxygen source,
Has a secondary combustion nozzle in a horizontal or obliquely downward direction at a side portion of the upper lance at a position isolated upward from the tip portion,
And inside the phase lance,
A first supply path for supplying a powder different from a solid oxygen source together with the oxygen-containing gas for blowing through the main hole nozzle, or for supplying the oxygen-containing gas for blowing through the main hole nozzle;
A second supply path for supplying an oxygen-containing gas for secondary combustion through the secondary combustion nozzle;
Supplying the oxygen gas for blowing to the molten iron bath surface from the said 1st supply path using the refinery phase lance which has a 3rd supply path for supplying a powder-shaped solid oxygen source with a conveying gas through the said hole hole nozzle. At the same time, the solid oxygen source is supplied from the third supply path together with the carrier gas to the molten iron bath near the place where the oxygen gas for blowing is supplied, and further, the secondary combustion oxygen is supplied from the second supply path. A method of refining molten iron for supplying gas into the furnace space of a converter type refining vessel to perform oxidative refining to suppress the adherence of the skull to the converter type refining vessel and to prevent the detriment associated with the skull attachment. The method of claim 1,
The distal end of the second supply path is blocked, so that the oxygen-containing gas supplied from the second supply path is configured not to join the first supply path and the third supply path. 3. The method of claim 2,
The refinery | melting method of the molten iron | metal which is comprised so that any 1 type, or 2 or more types of gas of a reducing gas, a carbon dioxide gas, a non-oxidizing gas, a noble gas may be supplied to the said 2nd supply path. 4. The method according to any one of claims 1 to 3,
A buffer space in which any one or two or more of air, reducing gas, carbon dioxide gas, non-oxidizing gas, and rare gas is present is provided around the third supply path, and the pressure of the gas present in the buffer space or A method of refining molten iron, wherein broken holes are detected in a third supply path based on a change in flow rate. 4. The method according to any one of claims 1 to 3,
The first supply path, the second supply path, and the third supply path are arranged on concentric circles. 5. The method of claim 4,
And the first supply path, the second supply path, and the third supply path are disposed on concentric circles. delete delete delete delete

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