JP2006213940A - Lance used for both blowing and in-furnace skull melting, and operation method of top-bottom-blown converter type refining furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently remove a skull while avoiding the care of securing the time needed for melting the skull, suppressing the erosion of refractory in a converter and reducing the frequency of water leakage from a lance. <P>SOLUTION: In the top/bottom-blown converter type refining furnace 8, the lance 7 which is used for the blowing and also the in-furnace skull melting, is provided with a tip part injecting hole 1 arranged at the tip part and injecting oxygen for blowing, and a side surface injecting holes 2 arranged on the side surface upward the tip part injecting hole 1 and injecting the oxygen for melting the skull, and is rotatable around the axis, is used to perform the blowing while melting the in-furnace skull 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for operating a smelting lance and melting ingot in a furnace, and an operation method of an upper bottom blowing converter type smelting furnace. The present invention relates to a lance that can be used for both blowing and in-furnace metal melting, and a method for operating an upper-bottom converter type refining furnace that uses this smelting and lance for melting metal in the furnace.

  Ingots and slag scattered during blowing in the converter adhere to the upper part of the inner wall of the converter. Adhered bullion and slag (hereinafter referred to as “adhered bullion”) grows each time the blowing is repeated, and becomes larger than a certain size and becomes an obstacle to pouring into the converter and charging scrap. . For this reason, it is necessary to remove adhering metal efficiently in blowing in a converter.

  It is known to remove the adhering metal mechanically by rubbing or hitting the scrap chute against the adhering metal as a means of removing the adhering metal, mainly the vicinity of the converter furnace. ing. However, this means can remove only the adhering metal in the vicinity of the furnace opening, and it takes a considerable time to remove the adhering metal that has grown to a certain size. In particular, this method is not efficient in converter blowing, in which the deposited metal in the furnace is likely to grow due to converter-type hot metal dephosphorization or the like. As described above, the method of mechanically removing the attached metal that has adhered to the converter furnace has a limit in the amount of attached metal that can be removed, and the time required for the removal is long.

  Patent Document 1 discloses an invention for dissolving and removing adhering ingots using non-steel melting lances during non-steeling after the completion of blowing, and Patent Document 2 further discloses an invention for rotating the bullion melting dedicated lances. Are each disclosed. However, in these inventions, it is necessary to secure time for dissolving the adhered metal because non-steel making is performed by dissolving and removing the adhered metal, and the temperature of the hot metal dephosphorization is low. Below, since the surface temperature of the adherence metal also decreases, even if oxygen is blown onto the adherence metal, it does not ignite (high temperature oxidation reaction), and the dissolution efficiency of the adherence metal tends to deteriorate. Thus, the method of spraying oxygen from a lance dedicated for melting metal during non-steeling to dissolve the deposited metal requires time for melting the deposited metal and is not efficient.

Therefore, in Patent Document 3, using a blowing lance and a furnace port metal melting lance equipped with both a nozzle for blowing and a furnace port metal melting, the adhesion metal is dissolved and removed simultaneously with blowing. The invention is disclosed. According to the present invention, it is efficient because it is not necessary to secure time for dissolving the adhered metal, and even when the temperature of the hot metal dephosphorization is low, the dissolved metal is efficiently dissolved and removed. It can be carried out.
Japanese Patent Laid-Open No. 1-136923 JP-A-6-25729 JP-A-8-127812

  In the invention disclosed in Patent Document 3, the nozzle for melting the furnace mouth metal is fixed and its position is unchanged. For this reason, the adhesion metal which exists in the direction to which the nozzle for melting the furnace mouth metal is directed is preferentially melted over the adhesion metal which exists in other directions. Therefore, if you continue to use this lance until the adherent metal in the whole furnace, including the attached metal in other orientations, melts, the refractory in the orientation that the nozzle for melting the furnace mouth metal points to Will damage it. In addition, the situation is the same when the adhered metal grows unevenly in the inner circumferential direction of the furnace, and the refractory with the less adhered metal is damaged.

  In addition, in order to melt | dissolve the adhesion | attachment metal in the whole furnace inside also including the adhesion | attachment metal | metal existing in the other direction except the direction which the nozzle for melting | dissolving a furnace mouth metal | bulb directs, the blowing disclosed by patent document 3 is carried out. In addition, it may be considered that a large number of nozzles for melting the furnace mouth metal in the lance for melting and melting the furnace mouth metal should be arranged on a concentric circle of the lance cross section (horizontal plane). However, if a large number of nozzles for melting the furnace mouth metal are arranged concentrically, the lance cooling water channel inside the lance inevitably decreases and the cooling capacity is insufficient, so that water leakage from the lance is induced. On the other hand, if the nozzles for melting the furnace mouth metal are arranged sparsely in a concentric manner, water leakage from the lance can be prevented, but the range in which the attached metal can be dissolved is narrowed.

  The present invention has a tip injection port arranged at the tip for injecting oxygen for blowing, and a side injection port arranged on the side surface above the tip injection port for injecting oxygen for melting ingot in the furnace. And a lance for both melting and ingot melting in the furnace, characterized in that it can rotate around its axis.

  Further, the present invention provides a tip injection port that is arranged at the tip and injects oxygen for blowing, and a side surface that is arranged on a side surface above the tip injection port and injects oxygen for melting the ingot in the furnace. Blasting and melting of in-furnace ingots, characterized in that the side injection port has 12 or less injection ports arranged concentrically in a lance cross section and is rotatable about its axis. It is a combined lance.

  From another point of view, the present invention is a top bottom blowing converter type smelting furnace, which performs blowing while melting the ingot in the furnace using the above-described lance for both melting and ingot melting in the furnace. It is the operating method of the top bottom blowing converter type refining furnace characterized by this.

  In the operation method of the top bottom blowing converter type smelting furnace according to the present invention, melting of the ingot in the furnace is performed while the blowing and lance for melting ingot in the furnace are rotated during non-blowing and the blowing is performed. It is desirable to carry out the smelting and melting of the ingot in the furnace without rotating the lance.

  In the operation method of the top bottom blowing converter type refining furnace according to the present invention, it is desirable that the top bottom blowing converter type refining furnace performs hot metal dephosphorization.

  According to the present invention, in the top bottom blowing converter type smelting furnace, the smelting lance having a rotating function and the in-furnace metal melting lance are used. Can be efficiently removed. Moreover, the molten metal of the refractory of a converter can be suppressed, and adhesion metal can be removed, reducing the frequency of occurrence of water leakage from the lance.

The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory view showing the structure of the lance 7 for both blowing and melting in-furnace of the present embodiment, FIG. 1 (a) is an overall view, and FIG. It is a cross-sectional view of a part, and is an AA cross-sectional view in FIG.

  As shown in FIG. 1 (a) and FIG. 1 (b), the lance 7 for both blowing and ingot melting is composed of a triple pipe, and the innermost inner cylinder 5a is used as the oxygen supply pipe 3 at the tip thereof. There is a nozzle 1 for blowing out oxygen for blowing.

  In the blow lance and in-furnace metal melting lance 7, a cooling water supply pipe 4 a is disposed so as to cover the oxygen supply pipe 3, and a cooling water drain pipe 4 b is further disposed so as to cover the cooling water supply pipe 4 a. The water is folded from the inner cylinder 5a side to the outer cylinder 5c side at the lowermost part of the intermediate cylinder 5b.

  Further, a metal melting nozzle 2 for ejecting oxygen for melting metal is arranged at a position above the lance side surface that is separated from the blowing nozzle 1 by a predetermined distance in the vertical direction. The metal melting nozzle 2 has an oxygen passage 2a communicating with the oxygen supply pipe 3, and the oxygen passage 2a is provided through the cooling water supply pipe 4a and the cooling water drain pipe 4b.

  In the present embodiment, the number of the metal melting nozzles 2 is four in the lance cross section, but is not limited to this, and if it is 12 or less on the concentric circle of the lance cross section, Good.

  FIG. 2 shows the number of bullion melting nozzles 2 provided on concentric circles in the cross section of the lance 7 for both blowing and melting in-furnace (the number of azimuths), and the frequency of lance water leakage troubles (life of the squirting nozzle 1). It is a graph which shows an example of the relationship with the frequency (%) which the nozzle 2 for metal melt | dissolution previously leaks.

For example, as shown in FIGS. 1B and 2, if the metal melting nozzles 2 are arranged sparsely in about four directions on the concentric circle of the lance cross section, the lance water leakage trouble does not actually occur.
However, as shown in the graph of FIG. 2, when the number of the metal melting nozzles 2 is 14 or more, the cooling water supply pipe 4a and the cooling water drain pipe 4b cannot be secured with sufficient inner diameter. Since the water channels are inevitably reduced and the cooling capacity is insufficient, water leakage troubles of the lance occur frequently and become a major operational problem. It is desirable to do. By setting the number of the metal melting nozzles 2 to 12 orientations or less, it is possible to melt the adhered metal in the entire furnace area without causing a water leakage trouble.

  Further, as shown in FIG. 1 (a), the lance 7 for both blowing and ingot melting in the present embodiment is provided with a known swivel pipe joint 6a and a lance rotation motor 6b at the upper portion. Via the pipe joint 6a, the interior of the oxygen supply pipe 3 and the inner cylinder 5a, the space between the cooling water supply pipe 4a and the inner cylinder 5a to the intermediate cylinder 5b, and further the cooling water drain pipe 4b and the intermediate cylinder 5b to the outside A space between the cylinders 5c is communicated. Thereby, the inside of the oxygen supply pipe 3 and the inner cylinder 5a, the space between the cooling water supply pipe 4a and the inner cylinder 5a to the intermediate cylinder 5b, and further between the cooling water drain pipe 4b and the intermediate cylinder 5b to the outer cylinder 5c. Are connected to the oxygen supply pipe 3, the cooling water supply pipe 4a and the cooling water drain pipe 4b in the inner cylinder 5a, the space between the inner cylinder 5a and the intermediate cylinder 5b, and the middle. The space between the cylinder 5b and the outer cylinder 5c can rotate. In other words, the portion below the swivel pipe joint 6a can be rotated about the lance center (vertical direction) as an axis.

  The blow lance and in-furnace metal melt melting lance 7 of the present embodiment is configured as described above. Next, a situation in which blowing is performed while melting and removing the metal attached to the inside of the furnace using the blowing and melting metal lance 7 will be described.

  FIG. 3 shows that the lance 7 for blowing and melting in-furnace metal of the present embodiment is disposed inside the top bottom blowing converter type refining furnace 8 to dissolve and remove the ingot 10 adhering to the furnace. It is explanatory drawing which shows the condition which blows. In the present embodiment, the top bottom blowing converter type refining furnace 8 performs hot metal dephosphorization.

  First, after inserting the lance 7 for both melting and ingot melting into the inside of the upper bottom blowing converter type refining furnace 8, the blowing is performed. At this time, oxygen for refining is injected from the blowing nozzle 1 of the lance 7 for both blowing and melting in-furnace metal to the hot metal 9 to perform blowing. On the other hand, from the nozzle 2 for melting the bullion, oxygen for melting the bullion is jetted toward the deposited metal 10 to melt the adhered metal.

  4 is an explanatory view showing a BB cross section in FIG. 3, FIG. 4 (a) shows a case where the lance 7 combined with blowing and ingot melting is not rotated, and FIG. 4 (b) shows blowing and A case where the in-furnace metal melting and lance 7 is rotated is shown.

  As shown in FIG. 4A, when the lance 7 for blowing and melting the ingot in the furnace is not rotated, the adhesion of the ingot 10 is preferentially proceeded from the direction in which the nozzle 2 for melting the ingot is directed. When there are four metal melting nozzles 2 as in this embodiment, the dissolution of the attached metal 10 proceeds from these four directions.

  On the other hand, when the blow lance and the in-furnace ingot melting lance 7 are rotated, as shown in FIG. 4 (b), the adhering ingot 10 in the entire furnace can be uniformly dissolved and removed. The rotation of the lance 7 for both blowing and in-furnace melting may be during blowing or during non-steel making. However, in order to rotate the lance 7 for both blowing and melting in-furnace during blowing, there is an increasing demand for stress on the lance base and the sealing performance of the swivel pipe joint 6 and the equipment load increases. On the other hand, if the blow lance and the in-furnace ingot melting lance 7 are rotated during non-steel making, a relatively simple facility can be used, so that an increase in facility load can be suppressed. From this point of view, it is desirable to remove the adhering ingot 10 while rotating the lance 7 for melting and melting in-furnace in-furnace during non-steel making.

  Also, if the lance 7 for both blowing and melting the ingot in the furnace is rotated intermittently for each heat, the damage to the converter refractory is further suppressed, and the adhered ingot 10 in the entire furnace area is dissolved and removed. can do.

  As described above, according to the present embodiment, since the lance 7 for both blowing and melting the ingot in the furnace is used, it is not necessary to secure time for melting the adhering ingot 10, and the adhering ingot 10 efficiently Can be dissolved and removed.

  Moreover, in this Embodiment, the space between the inside of the oxygen supply pipe 3 and the inner cylinder 5a, the cooling water supply pipe 4a and the inner cylinder 5a to the intermediate cylinder 5b using, for example, the swivel pipe joint 6, and the cooling water In the state where the space between the drain pipe 4b and the intermediate cylinder 5b to the outer cylinder 5c is in communication, the inside of the inner cylinder 5a, the inside of the inner cylinder 5a with respect to the oxygen supply pipe 3, the cooling water supply pipe 4a, and the cooling water drain pipe 4b. By configuring the space between the cylinder 5a to the intermediate cylinder 5b and the space between the intermediate cylinder 5b to the outer cylinder 5c to be able to rotate, the lance 7 for blowing and melting the ingot in the furnace is centered. Since it rotates about the axis (vertical axis), it becomes possible to blow acid from the metal melting nozzle 2 in any direction, so that the adhering metal 10 can be uniformly dissolved and removed throughout the furnace. In addition, partial damage to the converter refractory can be suppressed.

  Furthermore, the upper bottom blowing converter type refining furnace 8 of the present embodiment performs hot metal dephosphorization. As described above, the tapping temperature of the converter type hot metal dephosphorization is lower than the tapping temperature of decarburization blowing. Due to this, the amount of metal that adheres in the converter-type hot metal dephosphorization furnace is large, and the speed of deposition is fast. Furthermore, in the converter type hot metal dephosphorization, the temperature of the molten metal is low, so that the surface temperature of the adhered metal falls in a short time after the completion of the molten metal, and it is difficult to dissolve the adhered metal with oxygen during non-steel making.

  On the other hand, in the present embodiment, since the rotating function is imparted to the lance 7 for both blowing and melting in-furnace metal, even in the converter type hot metal dephosphorization furnace 8, the adhering ingot 10 Can be dissolved.

  Thus, according to the present embodiment, it is possible to efficiently remove the adhering metal 10 in the furnace while avoiding securing the melting time of the adhering metal 10. Moreover, the adhesion metal 10 can be removed while suppressing the melting loss of the refractory in the converter 8 and reducing the occurrence frequency of water leakage from the lance 7 for both melting and melting in the furnace.

Furthermore, the present invention will be specifically described with reference to examples.
In this embodiment, the present invention is applied to converter type hot metal dephosphorization. The conditions of this converter type hot metal dephosphorization are the case where the temperature in the pan after pouring is 1250 to 1400 ° C., and the [C] content after pouring is 3.0 to 4.0 mass%.

  In the lance 7 for blowing and melting in-furnace metal according to the present invention shown in FIG. 1, four laval nozzles having a diameter of 46 mm and an inclination angle of 15 ° are formed as the nozzle 1 for blowing, and the diameter 2 mm as the nozzle 2 for melting metal. The straight nozzles were formed in three positions at a pitch of 500 mm above the blowing nozzle 1 and at four locations on concentric circles of each height.

The lance 7 for blowing and melting in-furnace metal according to the present invention is inserted into the converter 8 so that the distance between the nozzle 1 for blowing and the hot metal 9 is 2.0 m. Blowing was performed under the conditions of 0 kg / cm ² and an oxygen flow rate of 30000 NM ³ / hr. And after every heat blowing, the lance was rotated every 10 degrees during non-steel making.

In addition, as Comparative Examples 1 to 3, adhesion metal was removed under the following conditions.
Comparative example 1: Mechanical removal by scrap chute Comparative example 2: Dissolution removal using a lance dedicated for melting metal during non-steel production Comparative example 3: Using a lance for melting and melting in-furnace without a rotating function The dissolution removal results are summarized in Table 1.

  As shown in Table 1, according to the example of the present invention, it was possible to efficiently remove the adhering metal 10 in the entire furnace while avoiding the melting time of the adhering metal 10. Moreover, the adhesion | damaged metal 10 was able to be removed, suppressing the melting loss of the refractory of the converter 8, and reducing the occurrence frequency of the water leak from the lance 7 combined with blowing and melting | dissolving the metal in the furnace.

On the other hand, in Comparative Example 1, it was possible to remove the attached metal near the furnace port, but it was not possible to remove the attached metal away from the furnace port.
In Comparative Example 2, in the case of converter type hot metal dephosphorization, the surface of the attached metal was low, so the attached metal was not ignited, and the attached metal could not be removed at all.

  Furthermore, in Comparative Example 3, it was possible to efficiently remove the attached metal in the direction directed by the nozzle 2 for melting the metal, but it was not possible to remove the attached metal in the other direction.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the structure of the blow lance of embodiment and the in-furnace metal melting | dissolving lance combined, FIG. 1 (a) is a general view, FIG.1 (b) is a cross-sectional view of the nozzle for metal melting | dissolving. FIG. 2 is a cross-sectional view taken along line AA in FIG. It is a graph which shows an example of the relationship between the number of bullion melting nozzles (azimuth number) provided on the concentric circle in the cross section of the blow lance and in-furnace metal melting lance and the lance water leakage trouble frequency (%). The explanation showing the situation where the blowing lance and the in-furnace ingot melting lance of the embodiment are arranged inside the upper bottom blowing converter type refining furnace and the ingot is blown while melting and removing the ingot in the furnace. FIG. It is explanatory drawing which shows the BB cross section in FIG. 3, FIG. 4 (a) shows the case where the lance which combines blowing and in-core metal melting | dissolving is not rotated, FIG. The case where the lance is rotated is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blowing nozzle 2 Barrel melting nozzle 2a Oxygen passage 3 Oxygen supply pipe 4a Cooling water supply pipe 4b Cooling water drain pipe 5a Inner cylinder 5b Intermediate cylinder 5c Outer cylinder 6a Swivel pipe joint 6b Lance rotation motor 7 Blowing and In-furnace melting and melting lance 8 Top-bottom converter-type refining furnace 9 Hot metal 10 Adhering metal

Claims (5)

A tip injection port that is arranged at the tip and injects oxygen for blowing, and a side injection port that is arranged on a side surface above the tip injection port and injects oxygen for melting the ingot in the furnace, Blasting and furnace ingot melting lance, characterized in that it can rotate around its axis. A tip injection port that is arranged at the tip and injects oxygen for blowing, and a side injection port that is arranged on a side surface above the tip injection port and injects oxygen for melting the ingot in the furnace, The side injection port has twelve or less injection ports arranged concentrically in a cross section of the lance, and is rotatable around an axis. In the top-bottom blowing converter type refining furnace, using the blowing and the in-furnace metal melting lance described in claim 1 or 2, blowing is performed while melting the in-core metal. Operation method of top-bottom converter type refining furnace. The melting of the in-furnace ingot is performed while rotating the blowing and in-furnace ingot melting lance during non-blowing, and the blowing is performed without rotating the blowing in-furnace ingot melting lance. The operation method of the top bottom blowing converter type refining furnace according to claim 3. The operation method of the top bottom blown converter type refining furnace according to claim 3 or 4, wherein the top bottom blown converter type refining furnace performs hot metal dephosphorization.

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