JPH0873921A - Method for measuring refining temperature of electric furnace and method for controlling refining - Google Patents

Abstract

PURPOSE: To shorten the operational time and to reduce the loss of energy by efficiently executing an oxygen blowing work and a temp. measuring and sampling work in the operation of an electric furnace. CONSTITUTION: In the electric furnace 11, nitrogen gas or inert gas is bottom- blown from bottom-blowing nozzles 11f, and while sufficiently stirring molten metal 14, oxygen is blown to the surface, on which the new molten metal is always circulated, from an oxygen lance 18. A supporting rod 22 for the temp. measurement and the sampling can slidably be displaced along the oxygen lance 18 and a temp. measuring probe 23 is fitted to the tip part of the supporting rod 22 so as to make freely attachable/detachable. A thermocouple is arranged at the tip part of the temp. measuring probe 23 and dipped into the molten metal 14, and the temp. can be measured. In the temp. measuring probe 23, a sample box is arranged and the molten metal 14 is taken out and the sample for analyzing the components can be taken.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric furnace that mainly melts and melts metals and the like (hereinafter sometimes referred to simply as "melting") while measuring the temperature and melting the metal while performing oxygen blowing. The present invention relates to a refining temperature measuring method and a refining control method of an electric furnace for performing component analysis and control of melting itself.

[0002]

2. Description of the Related Art Conventionally, for example, an electric furnace 1 constructed as shown in FIG. 20 has been used to melt and melt a main auxiliary material mainly containing metals and the like by heat energy generated by arc discharge of an electrode 2. There is. Examples of the main raw material include various metal scraps (scraps), alloys such as ferrochrome and ferro-nickel, metals such as nickel, ores such as chrome ores containing host rock, metal pellets including metals and metal oxides. Metal briquettes (solid metal and metal oxide raw materials) and the like. As auxiliary materials, there are quicklime for desulfurization refining and basicity adjustment, coke and pulverized coal (coal) as a carburizing source, and fluorspar. In any case, such a main auxiliary material is such that the metal melt to be secured has no problem in terms of composition component, quality, temperature, production yield, efficiency and productivity, economically, etc. Appropriately blended, melted and melted, and further refined. Therefore, slag (slag) is generated in addition to the molten metal.

For the purpose of decarburizing and refining a metal, shortening the melting time, reducing the energy consumption rate, etc., during the operation of the electric furnace 1, the metal melt is blown by blowing oxygen gas. When oxygen is blown in, it reacts especially with carbon and silicon contained in the main raw material, or reacts with carbon of pulverized coal which is recarburized with coke and carbonaceous materials that have been previously carburized. To generate heat. Blow-in of oxygen further reduces the amount of carbon and silicon in the molten metal melt as described above (decarburization, desiliconization), or agitates the melt to accelerate each of these reactions, It also contributes to making the composition components uniform.

Although some of the main and auxiliary raw materials charged and melted in the electric furnace 1 are also supplied from the raw material charging device 3, most of the main and auxiliary raw materials are supplied from the electric furnace 1 in the preheating device 4. After being sufficiently dehydrated and preheated by the high-temperature exhaust gas, it is charged into the electric furnace 1. The metal melt melted in the electric furnace 1 is transferred to the next step by the piggy carrier 5. Since the surroundings of the electric furnace 1 are in a high temperature environment and also in a poor environment in which dust generated in and around the furnace 1 is diffused, the furnace chamber 6 is provided in order to improve the surrounding environment. To isolate the surroundings.

On the other hand, the preheating device 4 is supplied with the main and auxiliary raw materials which have been premixed and charged from the basket 8 which is conveyed by the crane 7. The exhaust gas used in the preheating device 4 is cooled and cleaned by the dust collector 9 and then discharged. A nozzle 10 is provided at the bottom of the electric furnace 1 as described above, and nitrogen gas or an inert gas is blown into the molten metal in the furnace 1 to stir the molten metal to accelerate the respective reactions and to improve the composition components and The molten metal temperature is made uniform.

[0006]

The molten metal melted in the electric furnace 1 needs to be adjusted to have a temperature and components within a predetermined range when the molten metal is discharged from the electric furnace 1.
For this reason, during the operation of the electric furnace 1, it is necessary to measure the temperature of the molten metal and perform sampling for the analysis of the components of the molten metal at a considerable frequency between the meltdown of the charged main and auxiliary raw materials and the discharge of the molten metal. is there.

The temperature measurement and sampling of the molten metal are carried out separately from the oxygen blowing. However, if the oxygen blowing and the temperature measurement or sampling are performed as separate works according to the operation management conditions by manual work or a simple jig or device, the oxygen blowing device, the temperature measuring device, or the sampling device is individually operated in the electric furnace 1. It is necessary to move them in and out, and the time required for moving them in and out makes the overall operation time of the electric furnace 1 longer. Furthermore, when individually inserting the oxygen lance, the temperature measuring device or the sampling device into the electric furnace 1 and pulling out,
The heat energy in the electric furnace 1 escapes to the outside via the slag outlet (working port) and the like, which lowers the energy efficiency of the electric furnace 1 and further increases the melting energy, as well as the ambient temperature. It is easy to raise the work environment and worsen the working environment.

An object of the present invention is to improve the efficiency of oxygen sparging, temperature measurement and sampling work to improve workability by eliminating manual work, while ensuring safety, shortening work time and saving energy. An object of the present invention is to provide a refining temperature measuring method and a refining control method for an electric furnace which can be remotely operated or automated.

[0009]

SUMMARY OF THE INVENTION According to the present invention, an oxygen lance is inserted into a furnace while a molten metal such as a metal charged and melted in an electric furnace is bottom-blown and stirred, and the tip of the oxygen lance is inserted. Oxygen gas is blown toward the surface of the molten metal from a nozzle provided in the vicinity to blow oxygen, and the temperature measuring means provided on the oxygen lance is fed along the oxygen lance to be immersed in the molten metal. It is a refining measurement method for an electric furnace, which is characterized by performing measurement. Further, the present invention is characterized in that the oxygen lance is water-cooled, the nozzle at the tip is replaceable, and the oxygen lance is inserted into the furnace after the melting of the raw material such as metal is almost completed. Further, the present invention is characterized in that the temperature measuring means is provided with a sample chamber for collecting a molten metal during immersion, and an oxygen lance is drawn out of the furnace to collect a metal sample solidified in the sample chamber. Further, according to the present invention, the molten metal such as a metal that is charged and melted in the electric furnace is bottom-blown and agitated, an oxygen lance is inserted into the furnace, and the inside of the furnace is monitored by an ITV camera to unmelt. While avoiding the part, oxygen gas is blown toward the surface of the molten metal from a nozzle provided near the tip of the oxygen lance to blow oxygen, and the temperature measuring means provided on the oxygen lance is fed out along the oxygen lance. It is a refining control method for an electric furnace, which is characterized in that it is immersed in a molten metal and the temperature of the molten metal is measured to control the power supply amount.

[0010]

According to the present invention, the nozzle provided near the tip of the oxygen lance inserted into the furnace while bottom-blown and stirring the molten metal or the like charged and melted in the electric furnace. Oxygen is blown from to blow oxygen. A gas is blown into the molten metal from the bottom blowing nozzle provided in the bottom of the electric furnace to stir the molten metal sufficiently, and a portion of new molten metal is constantly circulated on the surface of the molten metal in the furnace from near the tip of the oxygen lance. By vigorously blowing oxygen gas, it is possible to sufficiently react with the molten metal while stirring it more sufficiently, and to perform decarburization and desiliconization refining of the molten metal. Further, sufficient desulfurization refining can be performed by sufficient stirring of the molten metal. Then, along with the oxygen lance, the temperature measuring means provided in the oxygen lance is fed out and immersed in the molten metal to measure the temperature of the molten metal. Therefore, the oxygen lance is electrically operated as a separate operation for measuring the temperature of the molten metal. There is no need to pull out from the furnace and insert and pull out the temperature measuring means again, in any case, shorten the operating time and prevent the loss of heat energy, further aiming at remote control or automation of each work without manual work. be able to.

Further, according to the present invention, since the oxygen lance is a water-cooled type, the temperature measuring means provided in the oxygen lance is fed out and immersed in the molten metal to measure the temperature of the molten metal. It can sufficiently withstand the high temperature inside, and the temperature measuring means can be sufficiently immersed in the molten metal to perform accurate temperature measurement. Further, since the nozzle at the tip of the oxygen lance can be replaced, it is easy to properly and accurately adjust the angle and spread angle of the oxygen gas. Therefore, even if the unmelted portion of the raw material such as metal remains in the furnace, it is possible to blow oxygen gas to the portion to accelerate the melting of the raw material.

Further, according to the present invention, the temperature measuring means is provided with a sample chamber for collecting the molten metal, and the oxygen lance can be drawn out of the furnace to collect the metal sample solidified in the sample chamber. Since oxygen sparging with an oxygen lance and temperature measurement and sampling of the molten metal can be performed as a series of operations or as separate operations, work time can be shortened and energy can be saved, while the operation of the molten metal can be performed manually. The temperature and components can be measured frequently and accurately, and the molten metal components can be stabilized early.

Further, according to the present invention, by monitoring the inside of the furnace with an ITV camera, oxygen is blown while avoiding the unmelted portion, or oxygen is blown in order to quickly dissolve the unmelted portion, Temperature measurement to control the amount of electricity,
Efficient melting and refining control can be performed.

[0014]

1 and 2 show the basic constitution of an embodiment of the present invention, and FIGS. 3 to 10 show the concrete constitution of each part constituting the embodiment of FIGS. Shown in Figure 1
1 to 14 show operating states of the embodiment shown in FIGS. 1 and 2, FIG. 15 shows a simplified electrical configuration for controlling the embodiment shown in FIGS. 1 and 2, and FIG. FIG. 17 shows a temperature measuring sampling step, and FIG.
Shows the change over time in the amount of electric power in the examples of FIGS. 1 and 2, and FIG. 19 shows the relationship between the lance height and the depression depth during oxygen sparging.

1 and 2, FIG. 1 shows an electric furnace 1.
1 is a vertical cross-sectional view of FIG. 1, and FIG. 2 is a sectional line II-II of FIG.
The cross-sectional view seen from is shown. The electric furnace 11 includes a furnace bottom 11a made of refractory material, a water-cooled furnace wall 11b, a water-cooled furnace lid 11c, and a small ceiling 11d made of refractory material. An electrode 12 for arc discharge that is vertically movable and rotatable is inserted into the small ceiling 11d. When using three-phase alternating current, three electrodes 12 are inserted, and when using direct current, for example, one electrode 12 is inserted. A hot water outlet 11e is formed on one side of the electric furnace 11, and a slag outlet 13 is provided on the side facing the hot water outlet 11e. The slag outlet 13 can be opened and closed by a door 13a. Above the furnace bottom 11a,
A molten metal 14 melted by arc discharge by the electrode 12 is stored, and a slag 14a floats above it. The furnace bottom 11a is provided with a bottom blowing nozzle 11f such as one or a plurality of porous plugs, and nitrogen gas or an inert gas is blown from outside the furnace 11 to stir the molten metal 14. For a large amount of molten metal 14, a plurality of bottom blowing nozzles 1
It is preferable to provide 1f.

A revolving device 15 is provided outside the electric furnace 11, an oxygen lance 18 for oxygen blowing is attached to an engaging node 17 at the tip of the revolving arm 16, and the electric furnace 11 is discharged from the slag outlet 13. Can be inserted inside. An ITV camera 19 is also provided to monitor the internal state of the electric furnace 11 from the slag outlet 13. The engaging node 17 is provided with a frame 20,
The support rod 22 can be slidably displaced in parallel with the axial direction of the oxygen lance 18 by the sliding device 21. The support rod 22 extends in the axial direction of the oxygen lance 18, and a temperature measuring probe 23 is detachably attached to the tip of the support rod 22 substantially perpendicularly to the axial direction. The support rod 22 can be angularly displaced around the axis, and the tip of the temperature measuring probe 23 is vertically displaced from the horizontal direction or the diagonal direction, which is the longitudinal direction of the slag outlet 13, which is substantially rectangular, in accordance with the angular displacement of the support rod 22. You can turn downwards. Therefore, if the tip of the temperature measuring probe 23 is directed vertically downward during temperature measurement by inserting the waste outlet 13 in the horizontal or diagonal direction, it is possible to easily insert from the narrow waste outlet 13, and conversely. Can be pulled out. Engagement node 17
Together with the link arm 24 and the swing arm 16,
Form two parallel sides of a parallelogram link. Since the oxygen lance 18 and the support rod 22 are one of the other two sides forming the parallelogram link, the swivel arm 1
Even if 6 turns a little, oxygen lance 18 and support rod 22
The direction of is almost unchanged. That is, the oxygen lance 18 and the support rod 22 can be moved substantially in the axial direction near the slag outlet 13.

FIG. 3 shows in more detail the construction associated with the swivel device 15 and the engagement node 17 of FIG. Swivel arm 1
A swivel cylinder 25 is provided for swiveling the 6 and the link arm 24. The turning cylinder 25 is pivotally supported by the turning device 15 by the trunnion 26, and when the rod is shortened, the turning arm 16 is moved to a position where the oxygen lance 18 and the support rod 22 are inserted into the electric furnace 11 as shown by a solid line. , When the rod is extended, the swivel arm 1
6 can be swiveled to the standby position as shown by the chain double-dashed line. The turning angle θ is, for example, 105 ° at maximum. This angle is detected by an encoder 29 that meshes with outer peripheral teeth 28 provided on the outer periphery of the swivel column 27. In the turning device 15, the trunnion 26 and the turning column 27 are used.
Are supported on the swivel base 30.

The periphery of the electric furnace 11 is isolated from the surrounding environment as a furnace chamber 31, and a furnace front door 32 is provided in front of the slag outlet 13. A turning device 15 as a moving means and a furnace front door 32
And the door 13a of the slag outlet 13 operates in conjunction with each other, and when the revolving arm 16 is in the state shown by the solid line in FIG. 3, the furnace front door 32 and the door 13a of the slag outlet 13 are opened, and the revolving arm 16 is rotated. Is swiveled as shown by the chain double-dashed line in FIG. 3, and when the oxygen lance 18 and the like are retracted, the furnace front door 32 and the door 13a of the slag outlet 13 are closed.
The link arm 24 is provided with a swing cylinder 33 for changing the length of the link arm 24 and causing swing displacement of the oxygen lance 18.

FIG. 4 shows a side view of the structure relating to the swivel device 15 and the engaging node 17 of FIG. Figure 5
Shows the swivel device 15 and the engaging node 17 in a further enlarged manner. The turning device 15 can be raised and lowered by the lifting cylinder 34. Engagement node 17
Is composed of a heat shield 35 and a base plate 36. The heat shield 35 receives the heat transmitted from the oxygen lance 18 inserted into the electric furnace 11 and rotates the swirl device 1.
Prevent turning around 5. A frame 20 for slidingly displacing the support rod 22, a sliding device 21, a swing cylinder 37, a swing bearing 38, a tilt cylinder 39, a tilt bearing 40, and the like are attached to the base plate 36.
The sliding device 21 is provided with a cover 41, inside of which the driving force is applied by the driving wheels 42.
3 is hooked between the tension bolt 45 and the connecting portion 46 via the pulley 44. When the drive wheel 42 is angularly displaced in one direction, the roller chain 43 is displaced corresponding to the displacement of the drive wheel 42 in the circumferential direction. Roller chain 4
Both ends of 3 are tension bolts 45 at the base of the support rod 22.
And is connected to the connecting portion 46 near the intermediate portion of the support rod 22. If the roller chain 43 is driven in one direction,
The support rod 22 also moves in conjunction with the roller chain 43.
The final position on the side where the support rod 22 is retracted is the stopper 47.
Is adjustable by. An angular displacement cylinder 48 is provided for angularly displacing the support rod 22 around the axis. A holder 49 is provided at the tip of the support rod 22, and the temperature measuring probe 23 can be attached and detached.

FIG. 6 shows the internal structure of the oxygen lance 18. A metal tip 50 is welded to the tip of the oxygen lance 18. A nozzle 51 is attached to the tip of the tip hardware 50 in the inclined direction. The nozzle 51 is attached to the tip hardware 50 by the screw portion 52. Oxygen lance 1
The main part of 8 has a triple pipe structure composed of an innermost oxygen gas pipe 53, an outer drainage pipe 54 and an outermost peripheral water supply pipe 55. Oxygen gas pipe 53, drain pipe 54
Between the water supply pipe 55 and the tip metal fitting 50, the welded portion 5
6a, 56b and 56c are joined respectively. The positions of the welded portions 56a, 56b, 56c are formed at positions displaced with respect to the axial direction of the oxygen lance 18. In particular, as shown in FIG. 6, the innermost oxygen gas pipe 5
3 and the metal fitting 50 are welded first, and then the drain pipe 54
This is convenient when the welding of the tip metal piece 50 is performed, and finally, the outermost water supply pipe 55 and the tip metal piece 50 are welded.

FIG. 7 shows a support rod 22 and a temperature measuring probe 23.
8 shows a configuration relating to FIG.
-VIII shows the sectional view seen from FIG. 9, and FIG. 9 shows the enlarged sectional view of the temperature measuring probe 23. The support rod 22 is an outer cylinder 57.
Inside, sliding displacement in the axial direction and angular displacement around the axial line are possible. A probe socket 58 is provided at the tip of the support rod 22, and can be easily attached to and detached from the temperature measuring probe 23. The rod 60 of the angular displacement cylinder 48 attached from the outer cylinder 57 via the bracket 59 angularly displaces the support rod 22 about the axis via the arm 61.

A thermocouple 62 is attached to the tip of the temperature measuring probe 23.
Is arranged, and the main part of the temperature measuring probe 23 is composed of a paper tube 63. The temperature measuring probe 23 is used for the molten metal 1 in the electric furnace 11.
It is dipped in 4 and eventually burned out. A sample chamber 64 is formed in the paper tube 63 and is lined with a refractory layer 65. When the temperature measuring probe 23 is immersed in the molten metal 14,
A part of the molten metal 14 flows into the sample chamber 64 and is solidified, so that a sample for component analysis can be collected.
The inner wall of the paper tube 63 is protected by a ceramic 66.
Replace the following parts as consumables.

FIG. 10 shows a door 13 provided at the slag outlet 13.
The structure of a is shown. The door 13a is vertically displaceable along the guide 67. It is the wire 69 driven by the lifting shaft 68 that raises the door 13a.
0 opens and closes the door 13a.

FIG. 11 shows a state in which the oxygen lance 18 is kept away from the waste port 13 of the electric furnace 11 and is on standby. FIG. 12 shows a state in which the oxygen lance 18 is inserted into the electric furnace 11 by the turning device 15. The tip of the oxygen lance 18 can be swung and displaced within a range of about 9 ° from the central axis according to the expansion and contraction of the swing cylinder 33. Further, by adjusting the turning cylinder 37, it is possible to adjust the position in the axial direction in which oxygen is blown. Temperature probe 23
Is waiting outside the electric furnace 11.

FIG. 13 shows a state in which the oxygen lance 18 is swung to the standby position by the swivel device 15, and the support rod 22 is swung to replace the temperature measuring probe 23 or take out the sample taken.

FIG. 14 shows a state in which temperature measurement is performed in the electric furnace 11. When performing temperature measurement, the temperature measurement probe 23 at the tip of the support rod 22 is projected further forward than the tip of the oxygen lance 18, and the tilting cylinder 39 and the swivel cylinder 37 are used to measure the temperature of the tip of the temperature measurement probe 23. Adjust the position.

FIG. 15 shows an electrical configuration for automatically controlling the embodiment shown in FIGS. 1 and 2. The control device 71 realized by computer control includes a cooling water pump 72,
The oxygen valve 73 and the hydraulic unit 74 are connected to the swing cylinder 25, the door 13a, the furnace front door 32, the swing cylinder 3
3, the lifting cylinder 34, the swing cylinder 37, the tilting cylinder 39, the drive wheel 42, the angular displacement cylinder 48, and the like can be controlled to perform the series of operations described above fully automatically.

FIG. 16 shows the operation contents of the oxygen sparging process. First, as preparation for operation, in steps a1 and a2, the operations of the cooling water pump 72 and the hydraulic unit 74 are started. At steps a3 and a4, the furnace front door 32 is unlocked and opened. At step a5, the waste outlet 13
Open the door 13a.

Next, as the charging process of the oxygen lance 18, the operations of steps a6 to a9 are performed. At a6, the elevating cylinder 34 is raised, and at a7, the swiveling cylinder 25 swivels the oxygen lance 18 to the standby position shown in FIG. It is loaded into the furnace at a8 and swung to the blowing position shown in FIG. The ejaculation is started at a9, and the elevating cylinder 34 is lowered while keeping the oxygen lance 18 horizontal at a10.

Next, as a sprinkling process by the oxygen lance 18, the swing cylinder 33 is operated in step a11,
The position of the surface of the molten metal 14 onto which the oxygen gas is blown from the nozzle 51 is changed. The inside of the electric furnace 11 is an ITV camera 1.
9 and avoid undissolved parts.
Alternatively, oxygen gas may be blown to the undissolved portion to promote the dissolution of the raw material.

Next, as a step of retracting the oxygen lance 18, steps a12 to a18 are performed. In a12,
The swing cylinder 33 is actuated to stop the oxygen lance 18 at a central position of swing, that is, at an angle of about 4 ° to the left with respect to the insertion and withdrawal directions at the slag outlet 13. At a13, the elevating cylinder 34 is raised. a
At 14, the swing cylinder 25 is operated to operate the oxygen lance 1.
8 is rotated to the ejaculation position, the ejaculation is stopped at a15, and a
At 16 the electric furnace 11 is pulled out of the furnace and swung to the standby position near the furnace front door 32. Oxygen lance 1 at a17
8 is rotated to a storage position away from the furnace front door 32, and a1
Lower with 8.

Next, as a process of stopping the operation, step a1
9, a20, door 13a of slag outlet 13 and furnace front door 32
To close. At step a21, the furnace front door 32 is locked. In steps a22 and a23, the hydraulic unit 74 and the cooling water pump 72 are stopped, respectively.

FIG. 17 shows the operation when the temperature measurement sampling step is carried out subsequent to the oxygen sparging step. After step a10 in FIG. 16, the pre-processes of steps b1 to b6 are performed. At b1, the supporting rod 2 is rotated by the swing cylinder 37.
Swivel 2 to change from a storage angle of about 10 ° to the left to an insertion angle of about 4 ° to the left. In b2, the support cylinder 22 is tilted by the tilting cylinder 39 and lowered to the vertical insertion position of about + 6.5 ° to about -4 °. At b3, the nitrogen gas for N ₂ purge is started to flow. In b4,
The support rod 22 is advanced relative to the oxygen lance 18 and inserted into the electric furnace 11. In b5, the support rod 22 is angularly displaced around the axis by the angular displacement cylinder 48, and the direction of the temperature measuring probe 23 is changed from a substantially horizontal direction or a diagonal direction of the slag outlet 13 to a downward direction. At b6, the temperature measuring probe 23 is lowered by the tilting cylinder 39, the tip is immersed in the molten metal 14, and the temperature is measured.

The sampling step of step b7 is performed simultaneously with the temperature measurement. When the temperature measuring probe 23 is immersed in the molten metal 14, part of the molten metal 14 is taken into the sample chamber 64 and collected as a sample for component analysis.

In the subsequent step, in step b8, the tilting cylinder 39 raises the support rod 22 to the vertical insertion position of about -4 °. In step b9, the angular displacement cylinder 48
The orientation of the temperature measuring probe 23 is changed from downward to horizontal. In step b10, the support rod 22 is retracted and pulled out of the electric furnace 11. In step b11,
Stop purging with nitrogen gas. In step b12,
The tilting cylinder 39 raises the support rod 22 from about -4 ° to a vertical standby position of about + 6.5 °. In step b13, the support rod 22 is rotated by the rotation cylinder 37 from a storage angle of about 4 ° left to about 10 ° left. Hereinafter, with respect to the oxygen lance 18, the above step a13-
The operation of a18 is performed.

Next, as the probe replacement work, the operations of steps b14 to b24 are performed. In b14 to b16,
The support rod 22 is swung by the swivel cylinder 37 to the probe replacement angle shown in FIG. 14 by about 35 °, and is lowered by the tilting cylinder 39 from about + 6.5 ° to about 0 ° to be horizontal, and is slid by the sliding device 21. Advance 1000 mm. At b17, the direction of the temperature measuring probe 23 is changed from horizontal to downward, and at b18, the temperature measuring probe 23 is further advanced by about 2200 mm. b
At 19, the temperature probe 23 is replaced. The sample of the molten metal 14 taken into the sample chamber 64 has been solidified by the time of replacement.

After the temperature measuring probe 23 is replaced, b
The support rod 22 is retracted by about 2200 mm at 20 and the temperature measuring probe 23 is returned from the downward direction to the horizontal direction at b21.
In step 2, it is further retracted by about 1000 mm. At b23, the tilting cylinder 39 moves the support rod 22 from about 0 ° to about +
Raise to 6.5 °. In b26, swing cylinder 37
The support bar 22 is swung up to the storage angle by. Hereinafter, operation stop operation is performed in steps a19 to a23.

FIG. 18 shows an operation pattern of this embodiment. (A) is a case where Ni-based stainless steel or the like is used for charging the solid raw material twice, and (b) is a case of Cr-based stainless steel or the like.
This is the case where the solid raw material is charged twice. In FIG. 18A, the first charge is melted from time t1 to time t2, the molten raw material is charged at time t2, and the material is heated from time t3 to time t4. The second charging is performed at time t5, and the operation preparation of the oxygen lance 18 is started at time t6. Time t
Oxygen is blown from 7 to t8, and temperature is measured and sampled from time t8 to t9. At time t10,
Dissolve one charge. In FIG. 18B, the first charging is started from time t11, the molten raw material is charged from time t12, and the first time is melted from time t13 to t14, the second charging is performed from time t15 to t16. Dissolve the raw materials charged in. At time t16 to 17, the third charging is performed, and at time t18, the operation preparation of the oxygen lance 18 is started. Oxygen is blown from time t19 to time t20, temperature is measured and sampling is performed until time t21, melting is performed until time t22, and melting for one charge is completed. At this time, if abnormalities in temperature and components are found with respect to the reference in the temperature measurement and sampling at t21, t2
Make adjustments for dissolution up to 2.

FIG. 19 shows the relationship between the lance height and the depression depth during oxygen sparging. Depth of molten metal 14 is L0
(M), depression depth L (m), lance height h
(M) and the flow rate of the oxygen-sending acid is I (Nm ³ ), the following first equation is established.

[0040]

[Equation 1]

Where ζ = 1.57 × 10 ⁻³ × Tr +
0.529, Tr is the temperature in the furnace, here 170
Set to 0 ° K. ρ is the density of the molten metal 14, which is 7,000 for molten stainless steel.

In order to perform a stable operation of oxygen blowing,
It is important that there is no (small) forming, that there is no (small) splash, and that the reaction efficiency is high, and it is necessary to set an appropriate L / L0 ratio and an appropriate oxygen transfer rate. In this embodiment, the operation is performed under the conditions shown in Table 1 below.

[0043]

[Table 1]

The amount of acid transfer is 800, 1000, 15
The four patterns of 00 and 2000 Nm ³ / Hr are set to be constant. In addition, the amount of solid oxide reduction due to oxygen sparging is
It is as shown in Table 2 below.

[0045]

[Table 2]

[0046]

As described above, according to the present invention, oxygen is blown to the surface while bottom-blowing a molten metal or the like, and decarburization or desiliconization by oxygen gas is performed while sufficiently circulating a new molten metal on the surface. It is possible to cause a reaction and perform efficient oxygen sparging. Since oxygen sparging and temperature measurement can be performed without extra work in and out, operating time can be shortened, heat energy loss can be reduced, and energy can be saved, and further remote operation or automation can be achieved.

Further, according to the present invention, since the oxygen lance is a water-cooled type, it can be inserted into a high temperature electric furnace and repeatedly used in the operations from oxygen blowing to temperature measurement sampling, thus reducing the running cost. can do. In addition, since insertion into the electric furnace is performed after the melting of the molten metal is almost completed, the heat energy required for melting is not lost to the oxygen lance for water cooling, and after the oxygen lance is inserted. Since the heat that contributes to the melting is generated by the oxygen blowing, it is possible to save energy as a whole. Since the tip nozzle of the oxygen lance is replaceable, it is possible to replace only the vicinity of the nozzle and continue the operation under the optimum blowing condition.

According to the present invention, the temperature measuring means is provided with a sample chamber for collecting the molten metal, the molten metal is sampled at the same time as the temperature measurement, and the oxygen lance is drawn out of the electric furnace to solidify the molten metal in the sample chamber. Since the metal sample is collected from, the temperature and components of the molten metal can be quickly grasped and it can be judged whether or not the temperature and components are adjusted to desired temperatures.

Further, according to the present invention, the inside of the electric furnace is monitored by the ITV camera, oxygen is blown away while avoiding the unmelted portion, or oxygen is blown to the unmelted portion to accelerate the melting, which is efficient. It is possible to reduce the working time by performing the sperm and save energy.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a basic configuration of an embodiment of the present invention when viewed from the front.

FIG. 2 is a cross-sectional view taken along section line II-II in FIG.

3 is a swing device 15 and an engaging node 17 of the embodiment of FIG.
It is a top view which shows the structure relevant to.

4 is a swing device 15 and an engaging node 17 of the embodiment of FIG.
It is a partial front view which shows the structure relevant to.

5 is a partial front view showing the configuration related to the engaging node 17 of the embodiment of FIG. 1. FIG.

FIG. 6 is a partially cutaway front view showing the configuration of the oxygen lance 18 of the embodiment of FIG.

FIG. 7 is a partially cutaway front view showing a configuration related to the support rod 22 of the embodiment of FIG.

8 is a cross-sectional view taken along the section line VIII-VIII in FIG. 7.

9 is a cross-sectional view showing the configuration of the temperature measuring probe 23 of FIG.

10 is a side view showing a configuration related to a door 13a of the slag outlet 13 of the embodiment of FIG.

FIG. 11 is a simplified plan view showing the operation of the embodiment of FIG.

12 is a simplified plan view showing the operation of the embodiment of FIG.

FIG. 13 is a simplified plan view showing the operation of the embodiment of FIG.

FIG. 14 is a simplified plan view showing the operation of the embodiment of FIG.

15 is a block diagram showing an electrical configuration for control of the embodiment in FIG.

16 is a flow chart of an oxygen sparging process in the embodiment of FIG.

17 is a flowchart of a temperature measurement sampling process of the embodiment of FIG.

FIG. 18 is a time chart showing an operating state of the embodiment of FIG.

FIG. 19 is a simplified cross-sectional view showing the relationship between the height of the oxygen lance from the surface of the molten metal and the depression of the molten metal.

FIG. 20 is a simplified cross-sectional view showing an operating state of a conventional electric furnace.

[Explanation of symbols]

 11 Electric Furnace 11f Bottom Blowing Nozzle 12 Electrode 13 Slag Outlet 13a Door 14 Molten Metal 14a Slag 15 Swirling Device 18 Oxygen Lance 22 Support Rod 23 Temperature Measuring Probe 31 Furnace Chamber 32 Furnace Front Door 51 Nozzle 62 Thermocouple 64 Sample Chamber 71 Control Device

Front page continued (72) Inventor Tsutomu Okuno 4976 Nomuraminami-cho, Shinnanyo-shi, Yamaguchi Nisshin Steel Co., Ltd. Shunan Steel Works

Claims (4)

[Claims] 1. An oxygen lance is inserted into a furnace while bottom-blown and stirring a molten metal or the like which is charged and melted in an electric furnace, and the molten metal is supplied from a nozzle provided near the tip of the oxygen lance. Oxygen gas is blown toward the surface to blow oxygen, and the temperature measuring means provided in the oxygen lance is fed along the oxygen lance and immersed in the molten metal to measure the temperature of the molten metal. Refining measurement method of electric furnace. 2. The oxygen lance is water-cooled, the nozzle at the tip is replaceable, and the oxygen lance is inserted into the furnace after the raw materials such as metals are almost completely melted.
Refining temperature measurement method of the electric furnace described. 3. The temperature measuring means is provided with a sample chamber for collecting molten metal during immersion, and an oxygen lance is drawn out of the furnace to collect a solidified metal sample in the sample chamber. Item 3. A refining temperature measuring method for an electric furnace according to Item 1 or 2. 4. The molten metal such as a metal charged and melted in an electric furnace is bottom-blown and agitated, an oxygen lance is inserted into the furnace, and the inside of the furnace is monitored by an ITV camera for unmelting. While avoiding the part, oxygen gas is blown toward the surface of the molten metal from a nozzle provided near the tip of the oxygen lance to blow oxygen, and the temperature measuring means provided on the oxygen lance is extended along the oxygen lance. A refining control method for an electric furnace, comprising immersing in a molten metal, measuring the temperature of the molten metal, and controlling the power supply amount.