WO2007099941A1 - Melting furnace and process for producing molten metal therewith - Google Patents

Abstract

The level of slag in a main body of melting furnace is controlled by carrying out periodic opening and closing of a batch slag discharge port, detecting at least either any quantitative change of pressure within the main body of melting furnace or any quantitative change of temperature of gas emitted from the main body of melting furnace at that time and, when the detected quantitative change is below a predetermined set value, opening the batch slag discharge port for a given period of time to thereby discharge slag from the the main body of melting furnace and lower the slag level within the main body of melting furnace, while, when the detected quantitative change is the predetermined set value or above, closing the batch slag discharge port for a given period of time to thereby maintain or increase the slag level within the main body of melting furnace.

Description

 Specification

 Melting furnace and molten metal manufacturing method using the same

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a melting furnace for continuously producing a molten metal such as molten iron by melting a solid reduced metal such as solid reduced iron, and a molten metal production method using the same. It is related with the grasp and control technology of the slag level inside.

 Background art

 [0002] In a molten iron production process in which a rotary hearth furnace and a melting furnace are connected, the applicant of the present application heat-reduced a compact containing iron oxide and a carbonaceous reducing agent in the rotary hearth furnace to obtain a metallization rate of 60. After reducing the solid reduced iron to not less than 50%, this solid reduced iron is sent to the melting furnace, and the carbon material supplied as fuel is burned with oxygen to control the secondary combustion rate in the melting furnace to 40% or less. , Developed a method for producing molten iron by melting the solid reduced iron to obtain a molten iron (see Patent Document 1)

) o

 [0003] However, as for the means for taking out the molten iron and slag generated by melting the solid reduced iron in the melting furnace, the applicant only provides a tap hole on the side wall of the melting furnace. No disclosure of specific means of retrieval o

 [0004] Of course, as with conventional blast furnaces, the melting furnace also uses molten iron and slag by means of repeatedly opening the tap holes and taking out the molten iron and slag and then closing the tap holes with mud at regular intervals. Can be taken out.

[0005] On the other hand, in Patent Document 2, a smelting reduction furnace in which an iron raw material, a charcoal material, and a slagging agent are charged as raw fuel into a melting furnace body, oxygen is blown, and the iron raw material is melted and reduced to directly produce molten iron In addition, on the left and right outside of the lower part of the melting furnace body, there are provided a hot metal reservoir and a slag reservoir communicating with the melting furnace main body through siphon ports, respectively, and the outlet is located at the tip of the hot metal reservoir. The one provided with a tap is disclosed. Patent Document 2 describes that the hot metal and slag in the melting furnace body are discharged out of the furnace from the hot metal reservoir and the slag reservoir through the outlet and outlet through the siphon port, respectively.ヽ The

 [0006] According to the smelting reduction furnace described in Patent Document 2, molten iron and slag can be continuously taken out of the furnace.

 [0007] Even though the intermittent removal method similar to that of the blast furnace or the continuous extraction method described in Patent Document 2 is employed, the deviation of the raw fuel component is not detected. In addition to fluctuations in the amount of injection and raw fuel input, the amount of molten iron and slag generated and the situation fluctuate due to the fact that an unsteady reaction takes place in the furnace.

 [0008] However, since the melting furnace is high temperature and a large amount of molten dust is generated, it is practically impossible to constantly monitor the slag level. It was very difficult to control to maintain the level.

 [0009] For this reason, even when the slag level rises abnormally, it is very difficult to detect and control the slag level, so high-temperature slag is ejected from the furnace seal part or the like, or water cooling of the furnace cover seal part is performed. There was a danger that high-temperature slag would come into contact with the water-cooled duct connected to the top of the furnace and the coolant would leak, causing a steam explosion.

 Patent Document 1: Japanese Patent Application Laid-Open No. 2004-176170

 Patent Document 2: JP-A-11 310814

 Disclosure of the invention

 [0010] Therefore, an object of the present invention is to easily and surely grasp the slag level in a furnace for melting a solid reduced metal such as solid reduced iron to produce a molten metal such as molten iron. A melting furnace that can be controlled simultaneously and a method for producing a molten metal using the same.

 In order to achieve the above object, in the melting furnace according to the present invention, a batch type discharge port is provided at a position higher than the discharge port for discharging the slag in the main body of the melting furnace body. At least one of the amount of change in the pressure in the main body and the amount of change in the temperature of the exhaust gas exhausted by opening and closing the push-type exhaust pipe is detected.

[0012] According to this configuration, the change in the pressure in the main body detected when the notch type exhaust valve is opened and closed. The slag level in the furnace can be easily and reliably grasped and controlled based on the amount of gasification or the temperature change of the exhaust gas. As a result, it is possible to manufacture molten metal by melting solid reduced metal while reliably preventing serious accidents such as slag jetting and steam explosions with melting furnace power.

 Brief Description of Drawings

 FIG. 1 is a front sectional view showing a melting furnace according to an embodiment of the present invention.

 FIG. 2 is a plan view showing a melting furnace according to an embodiment of the present invention.

 [FIG. 3] (a) is a sectional view showing a continuous discharge port, and (b) is a cross-sectional view showing a continuous molten iron discharge port.

 [FIG. 4] FIG. 4 is a flow diagram illustrating a method of controlling the slag level by detecting the amount of pressure change in the main body.

 FIG. 5 is a flowchart for explaining a slag level control method based on detection of an ID fan damper opening change amount, which is a modification of the embodiment of the present invention.

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described in more detail with reference to the drawings illustrating embodiments of the present invention. The case where solid reduced iron is used as the solid reduced metal and molten iron is produced as the molten metal is selected as a representative example, and the case where the molten iron and slag are continuously taken out will be explained. First, the structure of the melting furnace will be described.

 [Configuration of melting furnace]

 1 is a front sectional view showing a melting furnace according to an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 (a) is a sectional view showing a continuous discharge port, and FIG. 3 (b) is continuous molten iron. It is sectional drawing which shows a discharge port.

 [0016] As shown in Fig. 1, the melting furnace includes a main body la for melting solid reduced iron therein to obtain a molten metal containing molten iron M and slag S, and an outer side of a lower portion of the main body la. A melting furnace main body 1 having a molten metal reservoir portion lb provided in.

[0017] The main body (hereinafter also referred to simply as "furnace", for example, "inside the furnace" means "inside the main body of the melting furnace body".) The la ceiling has solid reduced iron R, carbonaceous material, Raw material input 2 for supplying raw fuel made of ironmaking agent or the like into the main body la and charcoal material in slag and carbon in Z or molten iron as a heat source for melting solid reduced iron R At the same time, an oxygen blowing lance 3 for secondary combustion of the gas generated in the furnace and exhaust gas after secondary combustion from the main body la An exhaust gas duct 4 is provided.

 [0018] The molten metal reservoir lb has an internal space communicating with the inside of the main body la through the siphon 5, and the molten metal reservoir lb has a continuous exhaust for continuously discharging slag S. There are provided an outlet (corresponding to the outlet of the present invention) 7 and a continuous molten iron outlet (continuous molten metal outlet) 8 for continuously discharging molten iron M. The continuous discharge port 7 and the continuous molten iron discharge port 8 have a groove shape extending in the vertical direction in FIG. 2, and the continuous discharge port 7 and the continuous molten iron discharge port 8 form the inside of the molten metal reservoir lb. The space is open upward and horizontally. In addition, in order to prevent the slag S from entering the recovered molten iron M as much as possible, the continuous waste pipe 7 is provided upstream of the continuous molten iron outlet 8 (that is, the side closer to the main body la). (See Fig. 2), its height position (ie, the lowest point position of the continuous discharge port 7) HA is the height position of the continuous molten iron discharge port 8 (ie, the lowest point of the continuous molten iron discharge port 8) (Point position) It should be higher than HB (see Fig. 3).

 [0019] Further, a notch type exhaust rod 9 configured to be openable and closable separately from the continuous exhaust rod 7 is provided on the side wall of the main body la. The height position of the Notch type exhaust rod 9 (that is, the position of the lowest point of the portion of the Notch type exhaust rod 9 that penetrates the side wall of the main body la) HC is from the height position HA of the continuous exhaust port 7 It ’s too expensive. For example, if a slide gate system is used as the open / close mechanism of the batch type outlet 9,

 [0020] Further, the melting furnace body 1 is for detecting the amount of change in the pressure in the main body la (hereinafter, also simply referred to as "furnace pressure") when the notch type exhaust rod 9 is opened and closed. A pressure gauge 11 is provided, and the exhaust gas duct 4 is provided with a thermometer 12 for detecting the amount of change in exhaust gas temperature when the batch type exhaust port 9 is opened and closed. The pressure gauge 11 for detecting the amount of change in pressure may be provided in the exhaust gas treatment facility (including the exhaust gas duct) for treating the exhaust gas from the melting furnace body 1 in addition to the melting furnace body 1. .

As shown in FIG. 1, for example, the siphon 5 may be configured by a gap between the bottom of the melting furnace body 1 and the partition wall 10 suspended from the ceiling of the melting furnace body 1. The siphon 5 may be provided in the molten metal reservoir lb. The partition wall 10 can be moved up and down, and the upper end height position HD of the siphon 5 can be adjusted by adjusting the immersion depth of the partition wall 10 in the molten metal (slag + molten iron). Is preferred. [0022] In the main body la of the melting furnace body 1, a raw material made of solid reduced iron R or the like is dissolved and separated into slag and molten iron, and a slag layer S is formed on the molten iron layer M! .

 [0023] The raw material charged from the raw material inlet 2 is submerged in the slag layer S and dissolved by the combustion heat of the gas generated in the carbonaceous material furnace by the oxygen blown by the oxygen blowing lance 3 or oxygen-enriched air. Is done. The melted raw material is separated into slag and molten iron and moves into the slag layer S and the molten iron layer M, respectively, and both the molten iron level ML and the slag level SL in the main body la rise. As a result, a hydraulic pressure difference occurs between the inside and outside of the main body la, and the increased amount of slag and molten iron passes through the siphon 5 and moves to the molten metal reservoir lb, and continuously from the continuous discharge port 7 and the continuous molten iron discharge port 8 respectively. Are exhausted.

 [0024] It should be noted that the upper end height position HD of the siphon 5 is set so that the exhaust gas in the main body la does not blow out of the furnace or the outside air does not leak into the main body la. It is necessary to keep the partition wall 10 lower than the bell SL, that is, to immerse the partition wall 10 in at least the molten metal. However, when the upper end height position HD of the siphon 5 is made lower than the molten iron level ML, that is, when the partition wall 10 is immersed into the molten iron layer M, the slag S in the main body la can pass through the siphon 5. Since the slag S cannot be discharged from the inside of the main body la, the upper end height position of the siphon 5 must be in the range of the slag layer S, that is, the partition wall 10 should be kept immersed in the slag layer S. .

 [0025] If the generation rate of slag and molten iron in the main body la of the melting furnace main body 1 and the discharge rate from the molten metal reservoir lb are balanced! SL is kept constant, and continuous molten iron can be produced.

[0026] However, the reduction rate of solid reduced iron obtained in the reduction furnace, particularly in the process of manufacturing molten iron by connecting the rotary hearth furnace (reduction furnace) and melting furnace described in Patent Document 1 above. The components such as the carbon content and the carbon content vary, the discharge rate of the reduction furnace fluctuates, the amount of raw fuel input to the main body la of the melting furnace body 1 fluctuates, the variation of these components, the fluctuation of the input amount, etc. If an unsteady reaction occurs in the main body la due to the occurrence of a slag, the balance between the generation rate of slag and molten iron in the main body 1a and the discharge rate from the molten metal reservoir lb is lost. Thus, the slag level SL in the main body la may vary greatly. However, a large amount of high-temperature and molten dust is generated in the main body la during oxygen blowing. Therefore, it is practically impossible to constantly monitor the slag level SL. In order to measure the slag level SL, it may be possible to use a means of interrupting the injection of oxygen or the like and charging the sub lance into the furnace, but this increases the equipment cost and increases the productivity due to the interruption of operation. There is a problem of decline, and practically it cannot be adopted.

[0027] In view of this, a method for grasping the slag level SL in the main body la without using the melting furnace having the above-described constituent power without stopping the operation will be described below.

[0028] [Method of grasping slag level]

 Open and close the notch type exhaust rod 9 periodically, and detect the amount of pressure change in the main body la and the change in temperature of Z or exhaust gas at that time, and grasp the ladder level SL in the main body la be able to.

[0029] First, a method for grasping the slag level SL by detecting the amount of change in pressure in the main body la will be described in detail.

 [0030] That is, when the batch type discharge port 9 is opened from the closed state for a certain time (for example, 5 seconds), if the slag level SL in the main body la is below the notch type discharge port 9, When the furnace is operated at a positive pressure, gas is rapidly ejected from the inside of the furnace, while when the melting furnace is operated at a negative pressure, the atmosphere rapidly enters from the outside of the furnace. 1 The pressure in a changes greatly (pressure decreases in positive pressure operation, and pressure increases / increases in negative pressure operation).

 [0031] On the other hand, when the slag level SL in the main body la is higher than the batch type exhaust port 9, the slag exists at the front side of the notch type exhaust port 9 inside the furnace, so that the melting furnace has a positive pressure. If the furnace is being operated in the furnace, the slag will also flow out of the furnace first, and the gas power ^, will not be blown out suddenly. The amount of intrusion is small V, and the degree of pressure drop in the main body la is small even when there is a slippage.

[0032] Therefore, by leaving the batch type discharge port 9 open for a certain period of time, if the degree of change (change amount) in the main body la at that time is large, the slag level SL is set to the batch type discharge port. The degree of pressure change in the main body 1a! / ヽ (change amount) Force S is small, and in this case, the slag level SL should be above the batch type outlet 9 I understand. [0033] It should be noted that the amount of change in the pressure in the main body la can be measured using a pressure gauge 11 installed in the melting furnace main body 1 (or in the exhaust gas treatment facility).

[0034] Next, a method for grasping the slag level SL from the amount of change in the temperature of the exhaust gas will be described in detail.

 [0035] That is, when the batch type discharge port 9 is opened from the closed state for a certain time (for example, 5 seconds), if the slag level SL in the main body la is below the notch type discharge port 9, When the furnace is operated at a positive pressure, high-temperature gas is rapidly ejected from the power inside the furnace, while when the melting furnace is operated at a negative pressure, the external power is cooled, the atmosphere rapidly enters, V, Even in the case of deviation, the temperature of the exhaust gas greatly decreases.

 [0036] On the other hand, when the slag level SL in the main body la is above the batch-type exhaust port 9, the slag exists on the front surface inside the furnace of the batch-type exhaust port 9, so the melting furnace is at a positive pressure. If the furnace is operated at low pressure, the slag will also flow out first, causing high-temperature gas power ^, while it will not blow out suddenly. The amount of intrusion into the atmosphere is small, and the degree of decrease in exhaust gas temperature is small even in the case of deviation.

 [0037] Therefore, by leaving the batch type exhaust port 9 open for a certain period of time, the degree of change in the temperature of the exhaust gas at that time (the amount of change) is large. In this case, the slag level SL is set to the batch type exhaust port. It exists below port 9 and the degree of change in exhaust gas temperature! / ヽ (change) is small! In this case, it can be seen that the slag level SL exists above the batch type outlet 9.

 [0038] The amount of change in the temperature of the exhaust gas can be measured using a thermometer 12 installed in the exhaust gas duct 4.

 [0039] Then, the batch type exhaust port 9 is opened and closed periodically (for example, at intervals of 5 min), and the degree of change (change amount) in the pressure in the main body la and the temperature of Z or exhaust gas is changed. By detecting it, it is possible to always know whether or not the slag level SL has exceeded the height position of the batch type slag 9 and quickly and accurately detect abnormal increases in the slag level SL. And can prevent serious accidents.

 [0040] [Sladder level control method by detecting the amount of pressure change in the main body when the batch type exhaust port is opened and closed]

By grasping the slag level SL as described above, serious accidents can be avoided in advance. However, we will not only grasp the slag level SL, but also explain in detail how to control the slag level to maintain it at a constant level.

 [0041] Hereinafter, a method using detection of the amount of change in the pressure in the main body la when the melting furnace is operated at a negative pressure will be described as a representative example and described with reference to FIG.

 [0042] As shown in Fig. 4, in order to start control of slag level SL, automatic control of furnace pressure is released.

 (OFF) and fix the damper opening of the ID fan that sucks exhaust gas (see S1). As a result, the amount of change in the pressure in the main body la due to the opening and closing of the notch type exhaust rod 9 can be detected with high sensitivity.

 [0043] Then, the batch type discharge rod 9 is opened for a predetermined time (for example, 5 seconds) (see S2). At this time, the pressure change amount ΔP in the main body la is compared with a predetermined set value ΔPs (see S3).

 [0044] And, in the case of Δ Ρ APS (that is, when the pressure in the main body la is almost the same before and after the batch type exhaust 9 is opened), the slag level SL is higher than the batch type exhaust 9 Since the batch type outlet 9 is kept open for a predetermined time (for example, 5 seconds), a certain amount of slag is discharged from the batch type outlet 9 and the slag level is determined. (See S2). Then, Δ Ρ and A Ps are compared again, and this loop (S2 → S3 → S) until Δ Ρ≥ A Ps (that is, until the slag level SL becomes lower than the batch-type discharge rod 9). Repeat 4 → S2).

 [0045] On the other hand, in the case of Δ Ρ≥Δ Ρ3 (that is, when the pressure in the main body la largely changes due to the opening of the batch type exhaust 9), the slag level SL is lower than the batch type exhaust 9 Since it is determined that the operation is successful (refer to S5), the batch type exhaust 9 is closed (refer to S6), and the internal pressure control is returned to ON (ON) and the damper opening of the ID fan is automatically controlled. Return (see S7). As a result, the melting furnace returns to normal operation and the slag level SL is maintained or raised. Then, after a predetermined time (for example, 5 min) has elapsed (see S8), the process returns to S1 again and the same control flow is repeated, and the slag level SL is maintained at a position lower than the batch type exhaust port 9. The

Note that the set value A Ps may be determined as follows, for example. That is, in the past operation, ΔP when the batch type outlet 9 was opened and the slurry from the batch type outlet 9 If there is no slag outflow from the batch outlet 9, set the upper limit of Δ P to Δ Ps!

[Method of maintaining slag level using elevating partition wall]

 Normally, the force that can maintain the slag level SL as described above If the slag level SL rises or falls excessively, it is necessary to return the slag level to the proper position more quickly.

 [0048] In such a case, it is preferable to use the partition wall 10 configured to be able to move up and down.

That is, when the slag level SL rises excessively, the partition wall 10 is raised, the immersion depth in the slag layer S is decreased, and the opening area of the siphon 5 is increased. The discharge rate of slag from the body la can be increased.

[0050] On the other hand, when the slag level SL is excessively lowered, the partition wall 10 is lowered, the immersion depth in the slag layer S is increased, and the opening area of the siphon 5 is reduced. The discharge rate of slag from within la can be reduced. Alternatively, the partition wall 10 is immersed in the molten iron layer M to prevent the slag in the main body la from flowing out of the siphon 5.

 [0051] The opening area can be manipulated only by the raising / lowering operation of the partition wall 10, but the slurry level cannot be controlled. If the partition wall 10 is immersed in the slag for a long period of time, it will be eroded and the immersion depth will change, resulting in poor accuracy. ! It is desirable that the partition wall 10 is moved up and down only when the slag level is continuously high or low.

 [Modification]

In the above embodiment, when the molten iron and slag are continuously taken out from the main body la of the melting furnace main body 1 by the combination of the siphon 5, the continuous discharge port 7, and the continuous molten iron discharge port 8, Although an application example has been shown, the present invention can naturally be applied to the case where the molten iron and the slag taken out from the main body of the melting furnace body are intermittently taken out by a tap hole similar to the blast furnace. That is, in the said embodiment, although the discharge port for discharging | emitting slag from the main-body part la is comprised by the continuous type discharge port 7, you may comprise the said discharge port by a tap hole. In this case, the batch type outlet should be located higher than the tap hole. [0053] In the above embodiment, an example in which both the pressure gauge 11 for detecting the amount of change in pressure in the main body la and the thermometer 12 for detecting the amount of change in exhaust gas temperature are installed. The indicated force When maintaining the slag level using only one of the amount of change in pressure in the main body la or the amount of change in exhaust gas temperature, it is not necessary to install both.

 For example, when only the thermometer 12 is installed, in the flowchart shown in FIG. 4, the change amount ΔT of the exhaust gas temperature is compared with a predetermined set value ΔTs in step S3. Then, on condition that Δ AT≥ATs, that is, when the exhaust gas temperature changes greatly due to the opening of the notch type exhaust 9, the batch type exhaust 9 is closed (see S6) Don't maintain SL and raise it.

 [0055] In the above embodiment, the partition wall 10 can be raised and lowered. However, the slag can be moved by the elevating partition wall 10 as described in the section of [Method of maintaining the slag level using the elevating partition wall]. If it is necessary to maintain the level, it can be fixed.

 [0056] In the above embodiment, one siphon 5 and one molten metal reservoir lb are installed one by one, and both the continuous discharge port and the continuous molten iron discharge port are provided in this one molten metal reservoir. As shown, two siphons may be provided, one with a slag reservoir, the other with a molten iron reservoir, and the former with a continuous drain and the latter with a molten iron outlet. .

 In the above embodiment, the oxygen blowing lance 3 is exemplified as the heat source supply means for dissolving the raw material, but an electrode may be used.

 [0058] In the above embodiment, solid reduced iron is exemplified as the solid reduced metal, and molten iron is exemplified as the molten metal, but as the metal element contained in the solid reduced metal and the molten metal, in addition to Fe, Mn, Ni, It may contain non-ferrous metals such as Cr, Mo and Ti.

[0059] In the above embodiment has illustrated a method of securing the Danba opening of release and ID fans furnace pressure automatic control for detecting the amount of change in the pressure within the main body 1 _a, shown in FIG. 5 As described above, the change amount of the damper opening may be detected instead of the change amount of the pressure in the main body la without releasing the automatic control of the furnace pressure and the automatic control of the damper opening of the ID fan.

[0060] Alternatively, the amount of change in the temperature of the exhaust gas may be detected based on a method for detecting the amount of change in the pressure in the main body la. In this way, the slag level can be determined more accurately. Can be gripped.

 [0061] [Summary]

 As described above, the melting furnace according to the present invention is a melting furnace that melts a solid reduced metal to produce a molten metal, and melts the solid reduced metal therein to contain a molten metal and slag. A main body part for obtaining the slag, a discharge outlet for discharging the slag, and a batch-type discharger provided at a position higher than the discharge port on the side wall of the main body part and configured to be openable and closable A melting furnace main body having a mouth, a pressure gauge for detecting a change in pressure in the main body when the batch type discharge port is opened and closed, and the main body when the batch type discharge port is opened and closed It is characterized by comprising at least one of thermometers for detecting the amount of change in the temperature of exhaust gas discharged from the component force.

 [0062] Further, after the melting furnace, the discharge port is constituted by a continuous discharge port for continuously discharging the slag from the main body part through a siphon, The furnace main body may be configured to further include a continuous molten metal discharge port for continuously discharging the molten metal via the main body part force siphon.

 [0063] Alternatively, after the melting furnace, the discharge port is configured by a tap hole for intermittently discharging the slag and the molten metal from the main body. .

 [0064] Further, the siphon may be configured by a gap between a bottom portion of the main body portion and a partition wall that is suspended from the ceiling portion of the main body portion so as to be lifted and lowered.

[0065] On the other hand, a first molten metal production method according to the present invention is a method of producing a molten metal using the melting furnace, in which the batch type waste gas is periodically opened and closed. Detecting a change in pressure in the main body or a change in temperature of the exhaust gas, and grasping and controlling a slag level in the main body based on the detected change. .

[0066] Further, a second molten metal production method according to the present invention is a method of producing a molten metal using the melting furnace, in which the batch type waste gas is periodically opened and closed. Detect the amount of change in pressure in the main body or the amount of change in temperature of the exhaust gas. When the amount of change is less than a preset value, the batch type discharge port is opened for a predetermined time to discharge slag from the main body and lower the slag level in the main body. When the amount of change is equal to or greater than the set value, the slag level in the main body is controlled by closing the batch-type evacuation valve for a predetermined time and maintaining and increasing the slag level in the main body. It is characterized by this.

 The third molten metal production method according to the present invention is a method of producing a molten metal using a melting furnace having a siphon as described above, and periodically opening and closing the batch type discharge port. At this time, the amount of change in pressure in the main body or the amount of change in temperature of the exhaust gas is detected, and when the detected amount of change falls below a predetermined set value, the batch type exhaust port is opened. The main body force slag is discharged for a predetermined time to discharge the slag level in the main body, and when the detected change is equal to or greater than the set value, the batch type outlet is closed for a predetermined time. The slag level in the main body is controlled by maintaining or increasing the slag level in the main body, and when the slag level in the main body is excessively increased or decreased, the slag level in the main body is increased into the molten metal in the main body. By adjusting the immersion depth of Kitsukamatsu cutting walls, it is characterized in that to control the slag level in the body portion.

Claims

The scope of the claims  [1] A melting furnace for melting a solid reduced metal to produce a molten metal,  A main body part for dissolving the solid reduced metal inside to obtain a molten metal containing molten metal and slag, a force of the main body part, a discharge port for discharging the slag, and the discharge on the side wall of the main body part. A melting furnace body having a batch type discharge port provided at a position higher than the outlet and configured to be openable and closable;  Pressure gauge for detecting the amount of pressure change in the main body when the batch type exhaust port is opened and closed, and change in the temperature of the exhaust gas discharged when the batch type exhaust port is opened and closed A melting furnace comprising: at least one of thermometers for detecting the amount.  [2] In the melting furnace according to claim 1,  The discharge port is configured by a continuous discharge port for continuously discharging the slag from the main body part through a siphon, and the melting furnace main body is formed from the main body part through the siphon. It is characterized by further having a continuous molten metal discharge port for continuously discharging the molten metal. [3] In the melting furnace according to claim 1,  The discharge port is constituted by a tap hole for intermittently discharging the slag and the molten metal from the main body. [4] In the melting furnace according to claim 2,  The siphon is constituted by a gap between a bottom portion of the main body portion and a partition wall that is suspended from the ceiling portion of the main body portion so as to be lifted and lowered. [5] A method for producing a molten metal using the melting furnace according to any one of claims 1 to 3,  The batch type exhaust pipe is periodically opened and closed, and a change in pressure in the main body or a change in temperature of the exhaust gas at that time is detected, and the change in the temperature in the main body is detected based on the detected change. A molten metal production method characterized by grasping and controlling a slag level. [6] A method for producing a molten metal using the melting furnace according to any one of claims 1 to 3. There,  The batch type exhaust is periodically opened and closed, and the amount of change in the pressure in the main body or the amount of change in the temperature of the exhaust gas at that time is detected, and the detected amount of change falls below a preset value. When the batch type discharge port is opened for a predetermined time and slag is discharged from the main body to lower the slag level in the main body, the detected amount of change is equal to or greater than the set value. A method for producing a molten metal, comprising: controlling a slurry level in the main body by closing a batch type exhaust rod for a predetermined time and maintaining and raising the slag level in the main body.  A method for producing a molten metal using the melting furnace according to claim 4,  The batch type exhaust is periodically opened and closed, and the amount of change in the pressure in the main body or the amount of change in the temperature of the exhaust gas at that time is detected, and the detected amount of change falls below a preset value. When the batch type discharge port is opened for a predetermined time and slag is discharged from the main body to lower the slag level in the main body, the detected amount of change is equal to or greater than the set value. The batch type exhaust rod is closed for a predetermined time to maintain and raise the slag level in the main body, thereby controlling the slurry level in the main body.  When the slag level in the main body is excessively increased or decreased, the slag level in the main body is controlled by adjusting the immersion depth of the partition wall in the molten metal in the main body. A method for producing molten metal.