JP5426988B2 - Molten metal production equipment - Google Patents

Description

  The present invention relates to a molten metal production apparatus for producing a molten metal by reducing and melting a bulk metal raw material such as a carbonaceous material-incorporated metal oxide agglomerate directly in an electric heating melting furnace such as arc heating without preliminary reduction. Regarding improvements.

  As a new iron-making method that replaces the conventional blast furnace method and smelting reduction method, the carbonized metal oxide agglomerates are pre-reduced in a rotary hearth furnace to form a solid reduced metal, which is then used as an arc furnace or submerged arc furnace. Various molten metal manufacturing processes for obtaining molten metal by melting in an electric furnace such as the above have been proposed (for example, see Patent Documents 1 to 4).

  However, these processes require a structure comprising two steps of a preliminary reduction step using a rotary hearth furnace and a melting step using a melting furnace, and require a means for transferring solid reduced metal from the rotary hearth furnace to the melting furnace. In addition to increasing the equipment cost as a total process due to the need for two exhaust gas treatment systems, there is a problem that heat loss is large and the energy intensity cannot be sufficiently reduced.

  Therefore, the present inventor has made various studies on specific methods for producing molten metal by reducing and melting carbonaceous material-containing metal oxide agglomerates using only an electric heating furnace without using a rotary hearth furnace. As a result of the implementation, the following invention has been completed, and a patent application has already been filed (Japanese Patent Application No. 2009-105397; hereinafter, the invention according to this patent application will be referred to as “prior application invention”).

  As shown in FIG. 3, the molten metal production apparatus according to the above-mentioned prior application invention is a flat furnace in which the raw material charging chutes 4 and 4 are disposed at both ends 2 and 2 of the furnace width, the electrode 5 is disposed at the center of the furnace width. Stationary non-tilting electric heating furnace with a secondary combustion burner 6 installed on the ceiling 1. Here, an arc furnace is used, and the charcoal material A is previously charged from the chutes 4, 4 and descends below the electrode 5. A carbonaceous material packed bed (corresponding to the “raw material packed layer” of the present invention) 12 having a slope is formed, and then a carbonaceous material-containing metal oxide agglomerated material B is charged to lump the carbonaceous material packed layer 12 on the slope. An agglomerate layer (corresponding to the “bulk metal raw material layer” of the present invention) 13 is formed, and thereafter, the electrode 5 is subjected to arc heating to sequentially melt the lower end of the agglomerate layer 13 and the molten metal layer 14 is placed in the furnace. And the molten slag layer 15 are formed, and the agglomerated layer 13 is lowered along the slope of the carbonaceous material packed layer 12 The CO-containing gas generated from the agglomerate layer 13 is combusted with the oxygen-containing gas C blown from the secondary combustion burner 6 and the agglomerate layer 13 is heated by the radiant heat. Is.

  According to the prior invention, the CO-containing gas generated from the agglomerate layer is moved to the secondary combustion burner while moving the agglomerate layer toward the electrode along the slope of the raw material packed layer formed in the furnace. It burns with the oxygen-containing gas blown from, heats the agglomerate layer itself with its radiant heat, preliminarily reduces, and this prereduced agglomerate layer is reduced and melted by arc heating near the electrode to melt Since it is made of metal, molten metal can be obtained directly from the carbonized metal oxide agglomerate in a single process, and both the equipment cost and the energy intensity can be greatly reduced compared to the conventional method.

  However, the molten metal production apparatus according to the invention of the prior application is a mixed state of the CO-containing gas generated in the furnace and the oxygen-containing gas C blown from the secondary combustion burner 6 installed in the flat furnace ceiling 1. Therefore, there has been a demand for further improvement of secondary combustion efficiency and further improvement of energy efficiency.

  Further, when a large amount of oxygen-containing gas C is blown from the flat furnace ceiling 1, the gas comes into contact with the electrode 5, and the consumption of the electrode 5 is remarkably reduced. Although the partition wall 9 is provided between them, the consumption of the electrode 5 is suppressed by the partition wall 9, but the problem that the partition wall 9 is damaged remains.

  On the other hand, the introduction of the oxygen-containing gas C from the furnace width end 2 is difficult because the carbon material packed bed 12 exists. In addition, the introduction of the oxygen-containing gas C from the end portion in the longitudinal direction of the furnace is possible because it can be blown away while avoiding the carbon material packed bed 12, but it is difficult to spread the oxygen-containing gas C throughout the longitudinal direction of the furnace. Therefore, there is a problem that the secondary combustion efficiency is lowered.

Special table 2000-513411 gazette JP-T-2001-515138 JP-T-2001-525487 JP 2003-105415 A

  Therefore, the present invention is an apparatus for producing a molten metal by reducing and melting a bulk metal raw material such as a carbonaceous material-incorporated metal oxide agglomerate directly in an electric heating melting furnace without preliminary reduction. It aims at providing the molten metal manufacturing apparatus which can improve combustion efficiency further.

According to the first aspect of the present invention, an exhaust gas duct and a raw material charging chute are connected to an upper portion of a stationary non-tilting electric furnace having electric heating means, and the raw material charging chute is at one end of the furnace width. On the other hand, the electric heating means is installed so that an electric heating region heated by the electric heating means exists at the other end of the furnace width, and a secondary combustion burner is installed at the upper part of the furnace. A raw material packed bed having a downward slope from one end of the furnace width to the electric heating region, with a predetermined amount of carbonaceous material and / or bulk metal raw material being charged into the furnace in advance from the raw material charging chute Then, a bulk metal raw material is continuously or intermittently charged from the raw material charging chute to form a bulk metal raw material layer on the slope of the raw material packed layer, and then the electric heating Electric heating by means By sequentially melting the massive metal raw material in the vicinity of the lower end of the massive metal raw material layer, a molten metal layer and a molten slag layer are formed in the furnace, and the massive metal raw material layer is formed along the slope of the raw material packed layer. While lowering, oxygen-containing gas is blown from the secondary combustion burner into the space in the furnace above the massive metal material layer to burn the CO-containing gas generated from the massive metal material layer, A molten metal production apparatus for producing a molten metal by heating and reducing a massive metal raw material layer, wherein a furnace ceiling portion of the stationary non-tilting electric furnace is connected to the other of the furnace width from one end of the furnace width. An apparatus for producing molten metal, comprising an inclined ceiling portion having a downward slope as a whole toward an end portion.
Here, the “ inclined ceiling part having a downward slope as a whole” means that the part of the inclined ceiling part is not inclined downward such as a horizontal part or a vertical part when viewed locally, and these parts are On average, it means a downward slope (same below).

According to the second aspect of the present invention, the exhaust gas duct and the raw material charging chute are connected to the upper part of the stationary non-tilting electric furnace having the electric heating means, and the raw material charging chute is connected to both ends of the furnace width. While being installed respectively, the electric heating means is installed so that an electric heating region heated by the electric heating means exists in the center of the furnace width, and a secondary combustion burner is installed in the upper part of the furnace, A predetermined amount of charcoal and / or massive metal raw material is charged into the furnace in advance from the raw material charging chutes installed at both ends of the furnace width, and a downward gradient from the both ends of the furnace width toward the electric heating region A raw material packed bed having a slope of the above is formed, and then a bulk metal raw material is charged continuously or intermittently from the raw material charging chutes installed at both ends of the furnace width, and the slope of the raw material packed layer is A bulk metal material layer is formed on top Thereafter, by performing electric heating with the electric heating means, and sequentially melting the massive metal raw material near the lower end of the massive metal raw material layer, a molten metal layer and a molten slag layer are formed in the furnace, and While lowering the massive metal raw material layer along the slope of the raw material packed layer, an oxygen-containing gas is blown from the secondary combustion burner into the space in the furnace above the massive metal raw material layer, and from the massive metal raw material layer A molten metal production apparatus for producing a molten metal by combusting a generated CO-containing gas and heating the massive metal raw material layer with its radiant heat, wherein a furnace ceiling portion of the stationary non-tilting electric furnace is It is a molten metal manufacturing apparatus characterized by comprising two inclined ceiling portions having a downward slope as a whole from both end portions of the furnace width toward the center portion of the furnace width.

  The invention according to claim 3 is the molten metal manufacturing apparatus according to claim 1 or 2, wherein the inclined ceiling portion has a slope shape.

  The invention according to claim 4 is the molten metal manufacturing apparatus according to claim 1 or 2, wherein the inclined ceiling portion is stepped.

In the invention according to claim 5, the inclination angle of the inclined ceiling portion is set within a range of [collapse angle of the massive metal material −15 °] or more and [static repose angle of the massive metal material + 15 °] or less. Item 5. The molten metal production apparatus according to any one of Items 1 to 4.

  The invention according to claim 6 is characterized in that the electric heating means is an electrode inserted into the furnace from the furnace ceiling, and the mounting angle of the secondary combustion burner to the furnace ceiling is The molten metal production apparatus according to any one of claims 1 to 5, wherein the flow of the oxygen-containing gas blown from the secondary combustion burner is at an angle that moves away from the electrode.

  The invention according to claim 7 is such that the structure of the gas blowing portion of the secondary combustion burner is such that the oxygen-containing gas blown by the secondary combustion burner swirls around the axis of the secondary combustion burner. It is a molten metal manufacturing apparatus of any one of Claims 1-6 comprised so that it might become.

  The invention according to claim 8 includes, as the bulk metal raw material, a carbonaceous material-incorporated metal oxide agglomerated material, metal scrap, reduced metal, metal oxide ingot ore, carbonaceous material-incorporated metal chloride agglomerated material, and metal oxide agglomerated mineral. It is 1 or more types selected from the group which consists of. It is a molten metal manufacturing apparatus of any one of Claims 1-7.

  According to the present invention, the furnace ceiling portion is formed so as to have a downward slope as a whole from the furnace width end portion toward the electric heating means, so that the space in the furnace above the massive metal raw material layer (free The volume of the space) is smaller than that of the prior invention, and the mixing of the CO-containing gas generated in the furnace and the oxygen-containing gas blown from the secondary combustion burner installed in the furnace ceiling is promoted. Combustion efficiency is improved and energy efficiency of the entire process is improved.

  In addition, if the furnace ceiling is viewed from the electrode side, it is formed so that it has a part that rises as a whole toward the furnace width end. The oxygen-containing gas blown from the secondary combustion burner can easily flow in the direction opposite to the electrode without providing a partition wall between the secondary combustion burner and the electrode, and the consumption of the electrode can be suppressed.

It is a figure which shows schematic structure of the molten metal manufacturing apparatus which concerns on embodiment of this invention, (a) is a longitudinal cross-sectional view, (b) is a top view. It is a figure which shows schematic structure of the molten metal manufacturing apparatus which concerns on another embodiment of this invention, (a) is a longitudinal cross-sectional view, (b) is a top view. It is a figure which shows schematic structure of the molten metal manufacturing apparatus which concerns on a prior application invention, (a) is a longitudinal cross-sectional view, (b) is a top view.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Embodiment]
[Device configuration]
In FIG. 1, schematic structure of the molten metal manufacturing apparatus which concerns on one Embodiment of this invention is shown. The apparatus according to the present embodiment uses an arc furnace (hereinafter sometimes simply referred to as “furnace”) as a type of electric furnace of a stationary non-tilting electric furnace, and the horizontal cross-sectional shape of the furnace is substantially rectangular. Thus, the furnace ceiling part 1 has a portion (inclined ceiling part) 1 ′ that becomes a downward gradient from the furnace width end part 2 toward the center part of the furnace width. In the present embodiment, a furnace will be described in which the inclined ceiling portion 1 ′ is formed in a staircase shape (a broken line portion connecting points PQRS in this example). An exhaust gas duct 3 and a plurality of raw material charging chutes 4 are connected to the furnace upper part (furnace ceiling part 1 in this example), and a plurality of electric heating means are provided in the furnace via the furnace ceiling part 1. The electrode 5 is inserted. The raw material charging chute 4 is installed at both ends 2 and 2 of the furnace width, while the electrode 5 is installed at the center of the furnace width. Further, a plurality of secondary combustion burners 6 are provided on the rising portion 1 a of the stepped portion of the furnace ceiling portion 1.

  The exhaust gas duct 3 is preferably installed on the side closer to the raw material charging chute 4 than the electrode 5. This is to prevent the oxidizing exhaust gas after the secondary combustion from flowing toward the electrode 5 and damaging the electrode 5.

  In this embodiment, when the furnace ceiling part 1 is viewed from the electrode 5 side, that is, from the center part side of the furnace width, the furnace ceiling part 1 has a part (inclined ceiling part) 1 'that is ascending toward the furnace width end part 2 as a whole. By forming in this way, the oxidizing exhaust gas after the secondary combustion has an upward gradient as a whole toward the furnace width end portion 2 formed between the inclined ceiling portion 1 ′ and the massive metal raw material layer 13. Since it flows to the exhaust gas duct 3 through the space (free space), contact with the electrode 5 is more reliably prevented, and wear of the electrode 5 is suppressed.

  In the molten metal production apparatus according to the invention of the prior application, as shown in FIG. 3, in order to prevent the oxidizing exhaust gas after the secondary combustion from contacting the electrode 5, the secondary combustion with the electrode 5 is performed. Although it has been recommended to provide the partition wall 9 that hangs down in the furnace between the burner 6, in this embodiment, the installation of the partition wall 9 can be omitted due to the above-described effects.

  Moreover, in the said prior-application invention, in order to prevent the exhaust gas after secondary combustion from short-circuiting to the exhaust gas duct 3 and to secure a sufficient amount of radiant heat transfer to the massive metal raw material layer 13, as shown in FIG. Although it was recommended that the partition wall 10 be provided between the secondary combustion burner 6 and the exhaust gas duct 3, in the present embodiment, as shown in FIG. The portion 1 can be brought close to the surface of the massive metal material layer 13, so that the exhaust gas after the secondary combustion passes near the surface of the massive metal material layer 13 and is emitted to the massive metal material layer 13. Since a sufficient amount of heat transfer can be ensured, the installation of the partition wall 10 can be omitted.

  In addition, in order to prevent the raw material charging chute 4 from being overheated and damaged by the high temperature exhaust gas, as shown in FIG. It is recommended to provide the partition 11 (however, not shown in FIG. 1).

  As described above, in the present embodiment, since at least the installation of the partition walls 9 and 10 can be omitted, troubles caused by damage to the partition walls can be reduced.

  In addition, a space formed between the furnace ceiling portion 1 and the massive metal raw material layer 13 so that the oxygen-containing gas C blown from the secondary combustion burner 6 does not shortcut to the exhaust gas duct 3 along the furnace ceiling portion 1. It is desirable that the height of the part be as constant as possible in the furnace width direction. Therefore, the inclination angle of the inclined ceiling portion 1 ′ is preferably as close as possible to the inclination angle of the surface of the massive metal raw material layer 13. Since the inclination angle of the surface of the massive metal material layer 13 is an angle between the collapse angle of the massive metal material B and the rest angle of repose, the inclination angle of the inclined ceiling portion 1 ′ is [the collapse angle of the massive metal material B− 15 ° (further −10 °, particularly −5 °)] or more and [static rest angle of the bulk metal raw material B + 15 ° (more + 10 °, particularly + 5 °)] or less. Here, the inclination angle of the staircase-shaped inclined ceiling portion 1 ′ is defined by the inclination angle (θ in FIG. 1) of a straight line connecting the furnace inner end portions (1 b and 1 b in FIG. 1) of each step of the staircase. Shall be.

  Further, the oxygen-containing gas C blown from the secondary combustion burner 6 and the CO-containing gas generated from the massive metal raw material layer 13 are turbulent due to the step shape of the inclined ceiling portion 1, so that mixing of these gases is not performed. Further promoted.

  Next, the angle at which the secondary combustion burner 6 is attached to the inclined ceiling portion 1 ′ is preferably set so that the flow of the oxygen-containing gas C blown from the secondary combustion burner 6 is away from the electrode 5. Thereby, it can further suppress that the exhaust gas after secondary combustion contacts the electrode 5. The direction in which the oxygen-containing gas C is blown from the secondary combustion burner 6 may be adjusted within a range of 10 to 135 ° on the side opposite to the electrode 5 with the vertical downward direction being the reference (0 °). If it is less than 10 °, the flow toward the electrode 5 cannot be sufficiently suppressed, and if it exceeds 135 °, there is a high possibility that the lining refractory of the step portion 1c in the stepped portion is damaged. More preferably, it is 30 to 120 °, particularly preferably 45 to 105 °.

  In the present embodiment, the secondary combustion burner 6 is attached at a right angle to the rising portion 1a of the stepped portion, so that the oxygen-containing gas C is blown in the direction opposite to the electrode 5 (90 ° with respect to the vertical downward direction as a reference). Direction).

  Further, the structure of the gas blowing portion of the secondary combustion burner 6 is configured such that the oxygen-containing gas C blown by the secondary combustion burner 6 becomes a swirl flow swirling around the axis of the secondary combustion burner 6. It is preferable to do this. Thereby, the secondary combustion of CO containing gas is further accelerated | stimulated. As the secondary combustion burner 6 that can obtain a swirling flow around the burner axis, for example, a swirl nozzle type burner having a plurality of blowout holes eccentric in the ejection direction, a burner having a spiral groove at the tip, or the like is used. Can do.

  In the lower part of the furnace, the raw material charging chute 4 is not provided (that is, the raw material packed layer 12 is not formed in the furnace). Are preferably provided. This is for facilitating the hole opening operation at the time of tapping.

  Further, a well-known heat exchanger (not shown) may be installed on the downstream side of the exhaust gas duct 3, thereby recovering sensible heat of the high-temperature exhaust gas discharged from the furnace, and from the secondary combustion burner 6. It can be effectively used as energy for preheating the oxygen-containing gas C to be blown in, generating electric power for arc, drying the pellet B, or the like.

  As the electrode 5, for example, a three-phase alternating current type that is excellent in thermal efficiency and is commonly used in an arc electric furnace for steelmaking is recommended. And, for example, it is recommended to adopt a configuration in which six electrodes are made from three sets of single-phase electrodes formed by combinations of two phases of three-phase electrodes.

  The electrode 5 is preferably subjected to a melting operation while its tip is positioned (immersed) in the bulk metal raw material layer 13 or the molten slag layer 15. As a result, the effects of radiant heating and resistance heating by the arc can coexist, melting can be further promoted, and damage to the inner surface of the furnace wall not protected by the raw material packed bed 12 can be suppressed. .

  Hereinafter, using this stationary non-tilting arc furnace, coal is used as a packed bed forming raw material for forming a raw material packed bed in the furnace, and a carbon material interior is used as a bulk metal raw material to be laminated on the raw material packed bed A case where molten iron is produced as a molten metal using only carbonaceous material-containing iron oxide pellets that are metal oxide agglomerates will be described as an example.

[Method for producing molten metal]
In advance, a predetermined amount of coal A as a packed bed forming raw material is charged into the furnace from the raw material charging chutes 4 and 4 installed at both ends 2 and 2 of the furnace width, From 2 and 2, a raw material packed bed 12 having a slope 12a having a downward slope directed to “below the lower end of the electrode 5”, which is an electric heating region heated by the electrode 5 as an electric heating means, is formed of coal A. deep. Here, the particle size of the coal A may be adjusted according to the particle size of the carbonaceous material-containing iron oxide pellets B so that the carbonaceous material-containing iron oxide pellets B described later do not sink into the voids of the raw material packed bed 12.

  Next, a carbonaceous iron-incorporated iron oxide pellet (hereinafter simply referred to as “pellet”) that is an agglomerated carbonaceous metal oxide agglomerated as a bulk metal raw material from raw material charging chutes 4 and 4 installed at both ends 2 and 2 of the furnace width. Also, only B is charged continuously or intermittently to form a pellet layer 13 as a bulk metal raw material layer on the slope 12a of the raw material packed layer 12. The blending amount of the interior carbon material in the pellet B may be determined by adding the target C concentration of molten iron to the theoretical C amount necessary for reducing iron oxide to metallic iron. The pellet B is preferably dried in advance so as not to burst (bursting) when entering the furnace interior.

  As described above, the height of the electrode 5 is preferably adjusted in advance so that the lower end of the electrode 5 is immersed in the pellet layer 13.

  Thereafter, the electrode is energized and subjected to arc heating, whereby the pellet B in the vicinity of the lower end of the pellet layer 13 is rapidly heated and sequentially reduced and melted, and separated into molten iron and molten slag as molten metal, The molten iron layer 14 and the molten slag layer 15 are formed in the lower part. In order to adjust the basicity of the molten slag layer 15, it is preferable to add a CaO source such as limestone or dolomite or an MgO source in advance to the pellet B.

  As described above, when the pellet B is sequentially melted from the vicinity of the lower end portion of the pellet layer 13, the pellet layer 13 itself moves toward the lower end portion of the electrode 5 along the slope of the raw material filling layer 12 by its own weight. It will descend in the furnace sequentially. Even if a part of the pellet B in the pellet layer 13 sinks into the gap of the raw material packed layer 12, a part of the pellet B stays in the furnace for a long time, so it is heated or reduced or heated before long. There is no problem because it is melted or melted, separated into molten iron and molten slag, and dropped into the molten iron layer 14 and molten slag layer 15 in the lower part of the furnace through the gap of the raw material packed layer 12.

  And when the pellet B in the pellet layer 13 approaches the electrode 5, it is efficiently heated by the radiant heat and resistance heating by the arc from the electrode 5, and the iron oxide in the pellet B is preliminarily turned into solid metallic iron by the interior carbon material. While being reduced, a CO-containing gas (combustible gas) is generated. When a carbon material containing volatile components such as coal is used as the interior carbon material, the volatile components devolatilized from the interior carbon material by heating are also added to the CO-containing gas.

  This CO-containing gas is combusted by, for example, oxygen gas as the oxygen-containing gas C blown in the horizontal direction from the secondary combustion burner 6 provided at each rising portion 1a of the stepped portion of the inclined ceiling portion 1 '. Next combustion) is promoted, and the pellet layer 13 is heated by the radiant heat. Thus, the pellet layer 13 heated by radiant heat preliminarily reduces the iron oxide in the pellet B to solid metal iron and CO-containing gas as in the case of radiant heating and resistance heating by the arc from the electrode 5. Therefore, the radiant heating by the secondary combustion is further promoted.

  As described above, the pellet B charged into the furnace from the raw material supply chute 4 is radiated by the secondary combustion (hereinafter referred to as “secondary combustion” while descending on the slope 12a of the raw material packed bed 12. It is also preliminarily reduced to a high metallization rate in a solid state by heat, and then melted by arc heating and resistance heating in the vicinity of the lower end portion of the electrode 5 to be separated into molten iron and molten slag.

  Therefore, the iron oxide concentration in the molten slag generated in the vicinity of the lower end portion of the electrode 5 is sufficiently low, and wear of the electrode 5 can be suppressed.

  The molten iron separated from the molten slag dissolves the carbonaceous material remaining in the pellet B to become a molten iron having a target C concentration.

  The molten iron and molten slag generated in this way can be discharged intermittently from the tap hole 7 and the tap hole 8 provided in the lower part of the furnace, for example, in the same manner as in the blast furnace.

  On the other hand, the raw material packed bed 12 formed by initially charging the coal A into the furnace is gradually heated in the furnace to remove the volatile components, and eventually becomes char or coke. The removed volatile matter is combusted by the oxygen-containing gas blown from the secondary combustion burner 6 together with the CO-containing gas generated from the pellet layer 13 and is effectively used as the radiant heating energy of the pellet layer 13. As described above, since the internal iron material C in the pellet B covers the reduction of the internal iron oxide and the carburization to the molten iron, the charred or coked raw material packed bed 12 is theoretically not consumed. In actual operation, it is gradually consumed during long-term operation due to direct reduction reaction with the pellet B submerged in the raw material packed bed 12 or carburization reaction to molten iron. Therefore, for example, in a state where the supply of the pellets B from the raw material charging chute 4 is stopped every certain operation period, at least arc heating is continued for a certain time, and the pellet layer 13 in the furnace is almost completely melted. After cutting and exposing the slope 12a of the raw material packed layer 12, the raw material filling is performed by charging a predetermined amount of coal (carbon material) A from the raw material charging chute 4 with the arc heating and secondary combustion interrupted. The furnace charge of layer 12 can be maintained.

  Since the inner surfaces of both side walls of the furnace width are covered with the raw material filling layer 12, the wear of the refractory in these portions is greatly suppressed. Therefore, a high-quality refractory and water-cooled structure excellent in corrosion resistance may be employed only on both side walls in the longitudinal direction that are not covered with the raw material packed layer 12, and the equipment cost can be greatly reduced.

(Modification)
In the said embodiment, although the example which forms the part (inclined ceiling part) 1 'used as a downward gradient as a whole in the furnace ceiling part 1 at step shape was shown, this invention is not limited to this, For example, FIG. As shown in FIG. In this case, as shown in the figure, the secondary combustion burner 6 is attached, for example, at a right angle to the portion of the down slope 1d of the furnace ceiling 1 so that the flow of the injected oxygen-containing gas C is kept away from the electrode 5. be able to. However, from the viewpoint of promoting the secondary combustion, as already described in the description of the above embodiment, the stepwise formation facilitates the turbulent flow of the gas, and the mixing is further promoted. The improvement effect is great. In addition, in this modification, the inclination angle of the part which becomes the downward slope as a whole of the furnace ceiling part 1 shall be defined by the inclination angle of the downward slope 1d.

In the above embodiment, regarding the arrangement of the raw material charging chute 4 and the electrode 5, the raw material charging chute 4 is installed at both ends 2 and 2 of the furnace width, while the electrode 5 is installed at the center of the furnace width of the furnace ceiling 1. Although the example which installs was shown, you may make it install the electrode 5 in the other end part 2 of a furnace width, while installing the raw material charging chute 4 in the one end part 2 of a furnace width. When this modification is adopted, since the slope of the raw material packed layer 12 formed in the furnace is only on one side, it is disadvantageous from the viewpoint of refractory protection compared to the above embodiment, but the furnace width is reduced. There is an advantage that the equipment can be made compact.
In the above embodiment, as an example of installing the electrode 5 in the center of the furnace width, an example in which the electrode 5 is installed on the center line of the furnace width has been shown. It is not limited to this, and it is allowed to be installed by shifting from the center line of the furnace width toward either end of the furnace width.

  In the above embodiment, the exhaust gas duct 3 and the raw material charging chute 4 are both connected to the furnace ceiling portion 1. However, the present invention is not limited to this, and either or both of them are connected to the furnace side wall. You may make it connect to the upper part of. When the raw material charging chute 4 is connected to the upper portion of the furnace side wall, the raw material charging chute 4 is automatically installed at the end of the furnace width.

  Moreover, in the said embodiment, although the substantially rectangular thing was illustrated as a horizontal cross-sectional shape of a stationary non-tilting type arc furnace, it is not limited to this, For example, the thing of a substantially ellipse or a perfect circle is used. May be. In this case, you may comprise so that three electrodes may be produced using each phase of a three-phase power supply instead of a single phase electrode. However, when a substantially rectangular one is used, there is an advantage that scale-up can be easily performed by extending the furnace longitudinal direction (direction perpendicular to the furnace width direction) while keeping the furnace width constant.

  Moreover, in the said embodiment, although the arc furnace was illustrated as a form of the electric furnace used for a stationary non-tilting type electric furnace, it is not limited to this, It is not limited to this, but by electric energy, such as a submerged arc furnace and an electromagnetic induction heating furnace. Any type of furnace may be used as long as it is a heating furnace. In addition, when using a submerged arc furnace, an electrode can be used as an electric heating means similarly to the said embodiment, and when using an electromagnetic induction heating furnace, a solenoid type heating coil can be used as an electric heating means.

  Moreover, in the said embodiment, although the pellet was illustrated as a form of the carbonaceous material interior metal oxide agglomerate B, you may employ | adopt a briquette. The briquette has a larger angle of repose than the spherical pellet, so in order to ensure the residence time on the inclined surface 12a of the raw material packed bed 12, it is necessary to increase the furnace height compared to the case of using the pellet, There is an advantage that the furnace width can be reduced.

  Moreover, in the said embodiment, although the example using only a carbonaceous material interior metal oxide agglomerate (carbon material interior iron oxide pellet) was shown as a lump metal raw material, a carbon material interior metal oxide agglomerate (carbon material interior iron oxide) was shown. Charcoal interior containing metal scrap (iron scrap), reduced metal (reduced iron [DRI, HBI]), bulk metal oxide ore (bulk iron ore), metal chloride instead of pellets and charcoal interior iron oxide briquettes Metal chloride agglomerates and metal oxide agglomerates (calcined iron oxide pellets, cold bond iron oxide pellets, iron oxide sinter) may be used, carbonaceous material interior metal oxide agglomerates, metal scrap, reduced metal One or more selected from the group consisting of a massive metal oxide ore, a carbonaceous material-incorporated metal chloride agglomerated material, and a metal oxide agglomerated mineral may be used.

  Moreover, in the said embodiment, although what contained only iron which is a non-volatile metal element was illustrated as carbonaceous material interior metal oxide agglomerate B, a volatile metal other than a non-volatile metal element was illustrated. It may contain elements such as Zn and Pb. That is, as the carbonaceous material-incorporated metal oxide agglomerate B, steel mill dust containing a volatile metal element can be used as the metal oxide raw material. The volatile metal element is heated in the furnace and volatilized and removed from the carbonaceous material-containing metal oxide agglomerate B. By adopting the method of the present invention, the temperature of the upper part of the furnace is increased by the combustion heat from the secondary combustion burner 6. Since it can be kept sufficiently high, the volatile metal element that has been volatilized and removed is reliably prevented from re-condensing in the upper part of the furnace, and the volatile metal element is efficiently recovered from the exhaust gas discharged from the furnace. Can do.

In the present specification, the volatile metal element means a metal element having a melting point at 1 atm of a metal simple substance or a salt thereof or the like at 1 atm or less. Examples of the metal simple substance include zinc and lead. Examples of the volatile metal element compound include sodium chloride and potassium chloride. Volatile metals in the volatile metal element compound are reduced to metals in an electric furnace (for example, an arc furnace, a submerged arc furnace), and a part or all of them are in a gaseous state in the furnace. In addition, the chloride of the volatile metal element is heated in the electric furnace, and a part or all of the chloride exists in the gaseous state in the furnace. On the other hand, the non-volatile metal element means a metal element having a melting point at 1 atm of a single metal or a compound such as an oxide thereof exceeding 1100 ° C. Examples of the metal simple substance include iron, nickel, cobalt, chromium, and titanium. Examples of the non-volatile metal oxide include CaO, SiO ₂ , and Al ₂ O ₃ . When using an arc furnace or submerged arc furnace as an electric furnace, a non-volatile metal element compound is used as a reduced metal element or as a non-reduced compound by heating or reduction reaction in the furnace. Although it can exist in a gas state in the (arc temperature region), it exists in a liquid or solid state away from the arc.

  Moreover, in the said embodiment, although only iron (Fe) was illustrated as a metal element which comprises the carbonaceous material interior metal oxide agglomerate B as a lump metal raw material, and the molten metal 14, Ni, Mn, Cr other than Fe Nonferrous metals such as may be contained.

  Moreover, in the said embodiment, although the means which adds a CaO source and a MgO source previously to carbonaceous material interior metal oxide agglomerate B was illustrated as a basicity adjustment means of molten slag, it replaced with or added to this means The raw material charging chute 4 may be charged with limestone or dolomite together with the carbonaceous material-incorporated metal oxide agglomerate B, or separately from the carbonaceous material-incorporated metal oxide agglomerate B with a separately provided chute. You may make it enter.

  Moreover, in the said embodiment, although coal was illustrated as a carbon material which forms the raw material packed bed 12, coke may be used. When coke is used, it has already been dry-distilled and no volatile matter is generated in the furnace, so the contribution to secondary combustion is reduced, but it is less pulverized than coal, so there is an advantage that the amount of scattering loss can be reduced. .

  Furthermore, a bulk metal raw material may be used as a filling layer forming raw material for forming the raw material filling layer 12 instead of or in addition to a carbonaceous material such as coal or coke. Even if a bulk metal raw material is used as a raw material for forming the raw material packed layer 12, reduction, melting, or carburizing / dissolving proceeds at the contact portion with the molten iron, but heat is generated at a portion away from the contact portion with the molten iron. Since it is difficult to transmit and the bulk metal raw material is maintained in a solid state, the raw material packed layer 12 once formed is maintained in a packed layer state for a long period of time. Moreover, since the temperature in the raw material packed bed 12 decreases as the distance from the contact portion with the molten iron increases and approaches the furnace wall, damage to the refractory due to the formation of molten FeO is not a problem.

  Further, in the above embodiment, the example in which the tap hole 7 and the drain hole 8 are separately installed on the opposite side walls has been described, but both may be installed on the same side wall, or the exhaust holes 7 and the drain holes 8 may be installed. It is also possible to omit the dredging hole 8 and install only the dredging hole 7 and discharge the molten iron and molten slag from the dredging hole 7.

DESCRIPTION OF SYMBOLS 1 ... Furnace ceiling part 1 '... Inclined ceiling part 1a ... Rising part 1b ... Protruding edge part 1c ... Step part 1d ... Down slope 2 ... End part of furnace width 3 ... Exhaust gas duct 4 ... Raw material charging chute 5 ... Electrode 6 ... Two Next combustion burner 7 ... Studded hole 8 ... Studded hole 9, 10, 11 ... Partition 12 ... Raw material packed layer 12a ... Slope 13 ... Bulk metal raw material layer (pellet layer)
14 ... Molten metal layer (molten iron layer)
15 ... Molten slag layer A ... Carbonaceous material (coal)
B ... Bulk metal raw material (carbon material-incorporated metal oxide agglomerates, carbon-inner iron oxide pellets)
C ... Oxygen-containing gas (oxygen)

Claims (8)

An exhaust gas duct and a raw material charging chute are connected to the upper part of a stationary non-tilting electric furnace having electric heating means,
The raw material charging chute is installed at one end of the furnace width, while the electric heating means is installed so that an electric heating region heated by the electric heating means exists at the other end of the furnace width. A secondary combustion burner is installed at the top of the furnace,
A raw material packed layer having a slope inclined downward from one end of the furnace width toward the electric heating region is charged in advance with a predetermined amount of carbonaceous material and / or massive metal raw material from the raw material charging chute. Formed,
Then, a bulk metal raw material is charged continuously or intermittently from the raw material charging chute to form a bulk metal raw material layer on the slope of the raw material packed layer,
Thereafter, by performing electric heating with the electric heating means, and sequentially melting the massive metal raw material near the lower end of the massive metal raw material layer, a molten metal layer and a molten slag layer are formed in the furnace, and While lowering the massive metal raw material layer along the slope of the raw material packed layer, an oxygen-containing gas is blown from the secondary combustion burner into the space in the furnace above the massive metal raw material layer, and from the massive metal raw material layer A molten metal production apparatus for producing a molten metal by burning a generated CO-containing gas and heating and reducing the massive metal raw material layer with its radiant heat,
Molten metal production characterized in that the furnace ceiling part of the stationary non-tilting electric furnace is composed of an inclined ceiling part that has a downward slope as a whole from one end part of the furnace width toward the other end part of the furnace width. apparatus. While connecting the exhaust gas duct and the raw material charging chute to the upper part of the stationary non-tilting electric furnace having electric heating means,
While the raw material charging chutes are respectively installed at both ends of the furnace width, the electric heating means is installed so that the electric heating region heated by the electric heating means exists in the central part of the furnace width. A secondary combustion burner is installed at the top of the furnace,
A predetermined amount of charcoal and / or massive metal raw material is charged into the furnace in advance from the raw material charging chutes installed at both ends of the furnace width, and a downward gradient from the both ends of the furnace width toward the electric heating region A raw material packed layer having a slope of
Next, a bulk metal raw material is charged continuously or intermittently from the raw material charging chutes installed at both ends of the furnace width to form a bulk metal raw material layer on the slope of the raw material packed layer,
Thereafter, by performing electric heating with the electric heating means, and sequentially melting the massive metal raw material near the lower end of the massive metal raw material layer, a molten metal layer and a molten slag layer are formed in the furnace, and While lowering the massive metal raw material layer along the slope of the raw material packed layer, an oxygen-containing gas is blown from the secondary combustion burner into the space in the furnace above the massive metal raw material layer, and from the massive metal raw material layer A molten metal production apparatus for producing a molten metal by burning a generated CO-containing gas and heating the massive metal raw material layer with its radiant heat,
The molten metal, wherein the furnace ceiling part of the stationary non-tilting electric furnace is composed of two inclined ceiling parts that are downwardly inclined as a whole from both ends of the furnace width toward the center part of the furnace width. manufacturing device.   The molten metal manufacturing apparatus according to claim 1, wherein the inclined ceiling portion has a slope shape.   The molten metal manufacturing apparatus according to claim 1, wherein the inclined ceiling portion has a step shape. Wherein the inclination angle of the inclined ceiling, any one of claims 1 to 4 within the scope of the following [static angle of repose + 15 ° of the bulk metal material] or [collapse angle -15 ° of the bulk metal material] The molten metal manufacturing apparatus described in 1.   The electric heating means is an electrode inserted into the furnace from the furnace ceiling part, and the angle of attachment of the secondary combustion burner to the inclined ceiling part is oxygen blown from the secondary combustion burner The molten metal manufacturing apparatus according to any one of claims 1 to 5, wherein the flow of the contained gas is at an angle such that the gas flows away from the electrode.   The structure of the gas blowing portion of the secondary combustion burner is configured such that the oxygen-containing gas blown by the secondary combustion burner becomes a swirl flow swirling around the axis of the secondary combustion burner. The molten metal manufacturing apparatus of any one of -6.   One or more selected from the group consisting of carbonaceous material-incorporated metal oxide agglomerates, metal scraps, reduced metals, metal oxide agglomerates, carbonaceous material-incorporated metal chloride agglomerates and metal oxide agglomerated minerals as the bulk metal raw material The molten metal manufacturing apparatus according to any one of claims 1 to 7.

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