The present invention, the molten slag or solidified slag lumps are produced in the steel making process, directly from the slag transport container, or through the inclined trough from the slag transport container, an electric furnace used in the process of reduction and injected into an electric furnace on.
　This application, on December 16, 2016, claiming priority on Japanese Patent Application No. 2016-244502 filed in Japan, the contents of which are incorporated herein.
BACKGROUND
[0002]
　In recent years, the demand for recycling of resources increases, desulfurization with converter or the like in the steel making process, along with separating and recovering valuable materials such as Fe and P from dephosphorization or slag generated by decarburization refining (steel slag) , be re-used by reforming steel slag to the high quality of the slag is desired.
[0003]
　For example, Patent Document 1, adding steel slag to steel melt melting furnace, heat and while modified steel slag by adding a reducing material, denatured slag is shifted Fe in the slag, Mn and P in the molten metal a first step of obtaining a, Mn and P in the molten metal is oxidized to shift sequentially modified slag, high Mn slag, second sequentially taking out the high P slag, slag processing method and a third step is disclosed there.
[0004]
　Patent Document 2, the carbon contained in the steel bath below the carbon content of 1.5 wt%, since the charged iron oxide content of 5 wt% greater than steel slag, carbonized steel bath by the introduction of carbon or carbon carriers to obtain the rate 2.0 wt% greater than steel bath, after which a method for reducing the oxides in the steel slag is disclosed. In this method, in order to suppress the foaming of slag accompanying the violent reaction between the steel bath ejected from (slag forming) and the furnace (overflow) when the slag-up, reduce the carbon content of the steel bath before the slag-on to relax the reaction rate at the time the slag is turned by placing is performed to a reduction treatment of the slag then raised the carbon content.
[0005]
　Patent Document 3, the process of continuously performing charged to reduction treatment molten slag from the transfer ladle into a reaction vessel having a molten iron layer and 溶滓 layer is described.
[0006]
　Molten slag of high temperature having flowability in Patent Document 4, temporarily held in the slag holding furnace, the molten slag layer to the molten iron layer in an electric furnace after having formed as a buffer zone, slag held in the molten slag layer injecting molten slag from the furnace, slag - it is described that supplies of carbon as a reducing material to the metal surface.
[0007]
　Structure of Patent Document 4, since the use of an electric furnace, the reduction reaction, the slag - than the reaction between the molten iron, the reaction of iron in slag (FeO) carbon content (C) and becomes dominant. Therefore, even if the C concentration in the molten iron is as low as 1.5 wt%, without carburization, it is possible to perform the reduction treatment of the slag, it is superior in that it can improve work efficiency .
[0008]
　Furthermore, the structure of Patent Document 4, rather than directly fed to the molten slag in the electric furnace, temporarily held in the slag holding furnace disposed adjacent to the electric furnace, buffer the molten slag layer on the molten iron layer in an electric furnace on which is formed as a band, while adjusting the injection amount, because it gradually injecting molten slag, that can facilitate control of the atmosphere sealed in the furnace, and can suppress the slag foaming during slag-on It is superior in point.
CITATION
Patent Document
[0009]
Patent Document 1: Japanese Sho 52-033897 Patent Publication
Patent Document 2: Japanese Kohyo 2003-520899 JP
Patent Document 3: Japanese Kohyo 2006-528732 JP
Patent Document 4: Japanese Patent No. 5522320 Publication
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　The slag treatment method described in Patent Document 1, because a reduction treatment using a converter, the molten metal and slag is strongly stirred. Therefore, when the high carbon concentration of the molten metal at the time the slag is turned, by the slag in contact with molten metal, the forming takes place the reaction is promoted. To avoid this, after turning the slag to a low melt carbon concentration, to promote the reduction reaction, to increase the carbon concentration of the molten metal by introducing carbon, and a number of times of the slag reduction treatment, Mn, it is necessary to repeat the oxidation and extraction process P, work efficiency and productivity are concerned decreases.
[0011]
　In slag reduction method described in Patent Document 2, because a reduction treatment using a converter, in order to perform the reduction treatment of the slag by increasing or decreasing the concentration of carbon in molten iron, decarburization Noborinetsu and carburized reduction will repeat the process of working efficiency and productivity are concerned decreases.
[0012]
　Since the upper end of the slag reduction method reaction vessel described in Patent Document 3 is open, it is not possible to control the atmosphere in the reaction vessel, the slag reduction is concerned that would be inhibited.
[0013]
　Due to the use of slag reduction method holding furnace described in Patent Document 4, in addition to the electric furnace requires holding furnace as slag reduction treatment apparatus, there is a problem that device becomes bulky. Further, since the contact area is increased between the use and the molten slag holding vessel surface holding furnace, there is a problem that heat radiation loss is increased.
　Further, the molten slag which may partially during the injection into the conveying or electric furnace is then solidified solidified slag. The solidified slag is preferably performed to a reduction treatment in terms of recycling.
　However, the slag reduction method described in Patent Document 4 due to the use of the holding furnace, there is a problem that can not be turned coagulation slag. Further, even if the coagulation slag were charged, it can cause slag foaming in contact with molten iron layer penetrate the molten slag layer and charged into the electric furnace by the size and weight, the molten slag layer functions as a buffer zone there is a problem that hard is.
[0014]
　The present invention has been made in view of the above problems, while maintaining the furnace atmosphere at a constant, large slag foaming and molten iron layer of molten slag or solidified slag lumps and electric furnace immediately after turned is vigorously mixed It prevents generating a, and an object thereof is to provide an electric furnace can be increased reducing processing efficiency.
Means for Solving the Problems
[0015]
　That is, it is an aspect of the present invention is as follows.
(1) One aspect of the present invention includes a cylindrical furnace wall, and the furnace lid provided at the upper end of the furnace wall, provided at a lower end of the furnace wall, and a deep bottom portion, for the deepest portion of the deep bottom portion height 150mm or more, the shallow bottom portion are the following regions 500 mm, an electric furnace having a furnace bottom, a having, wherein the electric furnace, directly from the slag transfer vessel, or inclined trough from the slag transport container slag charging port is provided which is capable of introducing molten slag or solidified slag lumps through, having said slag charging port is overlapped with the shallow bottom and plan view, in plan view of the shallow bottom portion to the furnace bottom area ratio of 5% or more, 40% or less.
(2) an electric furnace described in the above (1), the furnace lid or provided on both of the furnace lid and the furnace wall, and reducing material injection nozzle to inject reducing agent into the furnace, the furnace lid, it may have an exhaust duct provided in the.
(3) In the electric furnace described in the above (1) or (2), said slag charging port is provided in the furnace lid, it may be covered with slag-on door closure.
(4) above (1) to an electric furnace as claimed in any one of (3), of the furnace wall, which is positioned higher than the highest height of the shallow bottom part, tapping for discharging molten slag and mouth, of the furnace wall, wherein provided at a position lower than the shallow bottom portion may have a tap hole for discharging molten iron, wherein the electric furnace may be a stationary type.
(5) above (1) to an electric furnace as claimed in any one of (3) has a tilting unit for tilting the electric furnace, the furnace wall, at a position higher than the highest height of the shallow bottom portion provided, a tapping port for discharging the molten slag, provided on the extension of the deep bottom portion may have a furnace bottom tapping port for discharging the molten iron, the.
(6) The electric furnace according to (5), the furnace lid may be moveable between a side of the upper end and the furnace wall of the furnace wall, said slag charging port is the furnace lid may be open portion in a state that has moved laterally is formed above the furnace wall of the furnace wall.
Effect of the invention
[0016]
　According to the electric furnace mentioned above, without the use of slag holding furnace as disclosed in Patent Document 4, molten slag or solidified slag lumps are generated in steel making process directly from slag transport container, or slag transport container from be injected into the electric furnace through the inclined trough, it is possible to prevent the molten iron layer of molten slag and electric furnace immediately after being injected is mixed vigorously. Therefore, it is possible to the molten slag and the molten iron layer while preventing the thus generates a large slag foaming rapidly react, increasing the reduction treatment efficiency by keeping the furnace atmosphere non-oxidizing.
　Further, by introducing directly into an electric furnace hot solidified slag, and at the same time it is possible to recover the sensible heat of solidification slag, a process such as crushing, magnetic separation aging coagulation slag required in normal processes omitted, all the target slag becomes possible to smelting reduction. Furthermore not stationary electric furnace only, generally in tilting electric furnace which is widely used as a source of iron dissolution, since it becomes possible object can be achieved utilizing the present invention by adding small modification, existing facilities there is an advantage that the diversion is facilitated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
It is a process diagram showing the FIG. 1 slag treatment process.
FIG. 2 is a longitudinal sectional view showing an electric furnace according to the first embodiment.
3 is a cross-sectional view at the height 150mm from the furnace bottom of FIG.
4 is a schematic diagram showing a case to inject molten slag in an electric furnace.
5 is a schematic diagram showing a case to inject solidified slag lumps into an electric furnace.
6 is a longitudinal sectional view showing an electric furnace according to the second embodiment.
7 is a longitudinal sectional view showing an electric furnace according to the third embodiment.
8 is a diagram showing a simulation result of molten slag poured into the electric furnace.
9 is a diagram for explaining operation patterns in Examples 1 and 3 of the present invention.
Is a diagram for explaining operation pattern in Example 2 of FIG. 10 the present invention.
DESCRIPTION OF THE INVENTION
[0018]
　Preferred embodiments of the present invention with reference to the accompanying drawings.
　First, referring to FIG. 1, an outline of the slag treatment process using an electric furnace according to an embodiment of the present invention.
[0019]
　As shown in FIG. 1, molten pig iron is produced using a blast furnace in ironmaking step (S1), pig iron is refined to steel by using a converter or the like in the steel making process (S2). The steel making process (S2), the sulfur in the hot metal, phosphorus, desulfurization to remove carbon and the like, dephosphorization, and each step of the decarburization, removed to component adjustment gases and sulfur such as hydrogen remaining in the molten steel a secondary refining step of performing (S6), and a continuous casting step of casting the molten steel in a continuous casting machine (S7).
[0020]
　Of steel making process (S2), mainly dephosphorization (S4), decarburization (S5) is performed in the converter. In a converter furnace, molten iron is refined by using a flux composed mainly of calcium oxide. In this case, C in the molten iron by oxygen blown into the converter furnace, Si, P, Mn and the like are oxidized, the oxide is calcium oxide and ties slag. Furthermore, desulfurization, the dephosphorization, the step of decarburization (S3, S4, S5), components of different slag each (desulfurization slag, dephosphorization slag, decarburized slag) is generated.
[0021]
　In the description herein, collectively slag generated in the steel making process and steel slag, the steel slag is a concept including desulfurization slag, dephosphorization slag, decarburized slag. Also refers to the steelmaking slag in the high temperature molten state and the molten slag, similarly, the desulfurization slag in the molten state, respectively dephosphorization slag, decarburized slag, molten desulfurization slag, molten dephosphorization slag, and molten decarburization slag It referred to.
[0022]
　In slag treatment step (S10), the molten slag generated in the steelmaking process (S2), and transported to the electric furnace from the converter remain in the molten state, by continuously reducing melt modified with an electric furnace , recovered valuable materials in the molten slag (Fe, valuable elements such as P) in the molten iron layer is a layer of molten slag layer. In this case, in the electric furnace, Fe in the molten slag, the reduction processing of oxides of P, and the like, the processing for separating the granulated metallic iron (the iron) from the slag, as maintaining the basicity of the slag is carried out.
[0023]
　As a result, the high phosphorous molten iron is recovered containing phosphorus content or the like which is separated from the molten slag, and a steel slag molten slag is reformed reducing Kai, high-quality reduction slag substantial blast furnace slag is recovered . This reduction slag, FeO compared with the previous reduction, P 2 O 5 because of the low content of such can be recycled to the cement material, ceramic products and the like. Further, since the low expansion by adjusting the components such basicity of the molten slag is lowered, it can be used as roadbed material or aggregate.
[0024]
　Furthermore, dephosphorization for high phosphorous molten iron, which is the recovery by performing (S11), by shifting by oxidizing the P in the molten iron in the slag, separating high phosphorous molten iron in a high phosphoric slag and molten iron It is. High phosphate slag, can be recycled as a phosphate fertilizers and phosphoric acid raw materials. Further, the molten iron is recycled to the steel making process (S2), it is charged into the converter or the like.
[0025]
　Above was an overview of the slag treatment process according to the present embodiment. The process of the various molten slag produced in the steel making process (S2), it is preferable to be processed molten dephosphorization slag. Melting dephosphorization slag is a lower temperature than the melting decarburization slag contains a large amount of granulated metallic iron and phosphoric acid. Therefore, the molten dephosphorization slag, rather than oxidation treatment, by melting modified by reduction treatment, recovery efficiency of valuable elements by the process (Fe, P, etc.) is increased. Therefore, in the following description, as a molten slag to be processed, an example of using mainly molten dephosphorization slag. However, as the molten slag of the present invention is not limited to molten dephosphorization slag, it is possible to use molten desulfurization slag, melt decarburization slag, etc., any steelmaking slag generated in the steelmaking process.
[0026]
　Subsequently, with reference to FIGS. 2-7, an electrical furnace 1 is described for use in the slag treatment process (S10) in the slag treatment process.
　In the electric furnace 1 is S10, a furnace to form a molten slag layer 5 and the molten iron layer 6 therein.
　Electric furnace 1 has a furnace bottom 11, a cylindrical furnace wall 12, and a furnace roof 13. Furnace bottom 11, each of the inner surface of the furnace wall 12, and furnace roof 13, refractories are lined.
[0027]
　In the first embodiment and the second embodiment shown in FIGS. 2 to 6, the slag charging port 14 is formed in the furnace roof 13. Slag inlet 14 is covered with slag-on door 14a of the movable retractable in a direction A in FIG. Electric furnace 1 is sealed with the exception of the slag charging port 14, it can be kept in the furnace. Slag inlet 14 can be turned directly or by way of the inclined trough from the slag transport container molten slag 4 or coagulation slag lumps 4a from the slag transport container.
　In the third embodiment shown in FIG. 7, in a state where the furnace roof 13 is moved to the side of the furnace wall 12, an open part is formed above the furnace wall 12, this opening is the slag charging port 14.
　Further, a direct current furnace stationary type as an electric furnace 1 in FIG. 2 to FIG. 5, but illustrates a direct current furnace of FIG. 6 and FIG. 7, the tilting type, may be used alternating current furnace.
[0028]
　First, 2 to 5, illustrating a direct current furnace stationary type according to the first embodiment.
　In the center of the electric furnace 1, the upper electrode 15 and the furnace bottom electrode 16 are opposed vertically. A DC voltage is applied to the upper electrode 15 and the furnace bottom electrode 16, by generating an arc discharge between the upper electrode 15 and the furnace bottom electrode 16, the energy required to reduce the molten slag 4 is supplied.
　It is formed reducing material injection nozzle 33 in the furnace wall 12. Reducing agent injection nozzle 33 is a device for supplying auxiliary raw materials such as reduction material and reforming material necessary for the reduction treatment of the slag 4. Reducing material, coke powder anthracite powder, powdered carbonaceous material such as graphite powder are used. Reducing material is also a suppression means when the slag foaming occurs. Modifier mainly SiO in the slag 2 or Al, 2 O 3 is intended to adjust the concentration, silica sand, fly ash, and the like waste refractory powders can be used. Reducing agent injection nozzle 33 is also the suppression means when the slag foaming occurs. Reducing agent injection nozzle 33 may be formed on both the furnace wall 12 and furnace cover 13.
　The furnace lid 13 duct 32 is provided an exhaust duct.
[0029]
　Furnace bottom 11 has a deep bottom 11d, a bottom shallow shallow bottom 11a than the deep bottom 11d.
　Shallow portion 11a, when charging a molten slag 4 or coagulation slag mass 4a to the electric furnace 1, assuming that they are exposed from the surface of the molten iron layer 6, are placed closer to the furnace wall 12 there. During slag processing, in addition to sometimes molten iron or molten steel is charged into an electric furnace together with the molten slag, for hot metal is produced with the slag reducing the height of the molten iron layer 6 is increased. When thickened is molten iron layer beyond a certain, as it reduces the height of the molten iron layer 6 by opening the tap hole 18 for discharging molten iron, the period after the reduction by exposing the shallow bottom 11a from the molten iron layer 6, It is assumed to be charged with molten slag and then reduction treatment in this state to the electric furnace 1. However, shallow portion 11a when not exposed from the molten iron layer 6, not can not be charged with molten slag, if lower to some extent than the upper height of the shallow bottom part 11a of the molten iron layer, it was charged since vigorous mixing is suppressed between the molten slag 4 and molten iron layer 6, it is possible to achieve the object of the present invention.
[0030]
　In the first embodiment, as shown in FIGS. 2-5, an electric furnace 1 will be described with a circular cross-section. Shallow portion 11a, when charging a molten slag 4 or coagulation slag mass 4a to the electric furnace 1, assuming that the furnace bottom 11 is above the thickness of the molten iron layer 6 in the raised portion There, a region having an overlap with the slag charging port 14 in plan view, the furnace bottom 11 is partially raised portion. In other words, in a plan view, the existence region of the existence region and slag inlet 14 of the shallow bottom portion 11a is partially or entirely overlap. Without a slag holding furnace, molten slag 4 or coagulation slag mass 4a is generated by the steel making process, the injection from the slag-carrying container 21 directly, or via an inclined gutter 23 from the slag-carrying container 21 into an electric furnace 1 It is. Molten slag 4 or coagulation slag mass 4a, since flows through the slag charging port 14, the molten slag flowing from the spout would fall toward the shallow bottom portion 11a. That is, the shallow bottom portion 11a flows down from the slag charging port 14 will include a falling position of the molten slag 4 or coagulation slag lumps 4a.
　Shallow bottom 11a is formed, for example, by the furnace bottom 11 is shallower stepwise. Shallow bottom 11a is constituted by refractory similar to the inner surface of the other portions of the furnace bottom 11. The furnace lid 13 slag inlet 14 is formed.
[0031]
　Although FIGS. 2-5 in the hearth 11 is shallow bottom 11a by going one step shallower formed, the shallow portion 11a is not limited to this shape. For example, by the furnace bottom 11 becomes shallow over two or more stages, to shallow portion 11a may be formed, not a stepwise, by shallower form a continuous slope, shallow bottom 11a is formed it may be. Further, the shallow portion 11a may not necessarily have a horizontal surface as shown in FIG. Shallow bottom part 11a below the slag charging port 14, height 150mm or more for the deepest portion of the deep portion 11d, a following areas 500 mm, the area ratio in plan view of the shallow bottom part 11a against the bottom of the furnace 11 is less than 5% , as long as you meet the 40% or less, the total shallow portion 11a may be a stepped shape or slope shape. However, if the shallow portion 11a has a horizontal surface, without decreasing the furnace capacity than necessary, preferable in that it can secure an area ratio in a plan view of the shallow bottom part 11a against the bottom of the furnace 11 at least 5%.
[0032]
　Figure 4 As shown in 1-6, the basic assumptions, molten slag 4 or coagulation slag lumps 4a is inserted through the slag-carrying container 21 or slug transport container 21, through the inclined trough 23 into an electric furnace 1 If it is, molten slag 4 is turned from the slag charging port 14, it flows down into the molten slag layer 5. Although the molten slag layer 5 by flowing down molten slag 4 is disturbed, run down and the place has a shallow bottom 11a, since the molten iron layer 6 is not present in the lower layer of the molten slag layer 5 in this location, immediately turned molten slag 4 is not contact the molten iron layer 6. Therefore, molten slag 4 immediately after the injection, due to rapidly react with the molten iron layer 6, slag foaming is prevented.
[0033]
　As shown in FIG. 2, the shallow bottom portion 11a, the height H is 150mm or more for the deepest portion of the deep portion 11d, which is less area 500 mm. This, if there is 150mm or more height, newly molten slag 4 which is charged is effective to alleviate the situation in which vigorous mixing with molten iron layer 6 with the original is because expected. The reason why the height with respect to the deepest portion of the deep portion 11d is 500mm or less, while not meaning to be 500mm greater, because the so high that adverse furnace capacity decreases are concerned.
[0034]
　As shown in FIG. 3, S the area in plan view of the deep bottom 11d 1 , an area in plan view of the shallow bottom part 11a S 2 When the area ratio in plan view of the shallow bottom part 11a against the bottom of the furnace 11 ((S 2 / (S 1 + S 2 )) × 100) is more than 5%, is preferably 40% or less. By area ratio is 5% or more, can be the ratio of molten slag 4 or coagulation slag lumps 4a enjoy mixing relaxation effect is ensured, suppressing severe forming generation as a whole slag. If the area ratio is 40 percent, whereas it is hardly effect of suppressing the forming product is increased, and the molten iron capacity of the molten iron layer 6, the interfacial area between the molten iron layer 6 and the molten slag layer 5 becomes smaller , it is caused concern that the reduction efficiency is reduced. Moreover, since the shallow portion 11a exceeds 40% contained in the high current density region of the furnace bottom 11, the shallow bottom portion 11a is easily depleted.
　Incidentally, the shallow bottom portion 11a in the present invention "height H to the deepest portion of the deep portion 11d is 150mm or more, 500 mm or less in the region" because it is defined as, S 1 and S 2 the boundaries of the deepest portion of the deep portion 11d the height H to is the position of 150 mm.
[0035]
　Further, 4 and 5, the shallow bottom portion 11a, although Chinsen the molten slag layer 5 while exposed from molten iron layer 6 may be exposed from the molten slag layer 5. In this case, molten slag 4 or coagulation slag lumps 4a injected from the slag charging port 14, after impinging on the surface of the shallow bottom portion 11a, flows into the molten slag layer 5 flows down the surface of the shallow bottom portion 11a. By molten slag 4 collides with the surface of the shallow bottom part 11a, since the kinetic energy is attenuated, from the shallow bottom portion 11a, it is not the molten slag 4 or coagulation slag mass 4a to molten iron layer 6 is mixed vigorously. Accordingly, it is suppressed that the molten slag 4 or coagulation slag lumps 4a and molten iron is rapidly reacted, slag foaming is suppressed.
[0036]
　Here, when the solidified slag lumps 4a was charged, as shown in FIG. 5, have to be deposited on the first shallow bottom part on 11a is assumed, when in a state of being immersed in the molten slag layer 5 in the since the solidified slag lumps 4a to move from first dissolved in the molten slag layer 5 to the upper portion of the molten iron layer 6, it never solidified slag lumps 4a is mixed directly with the molten iron layer 6, contained in the coagulation slag mass 4a FeO, etc. to be found because it is avoided that react violently with C in the molten iron, thereby preventing slag foaming.
　Furthermore, by having a shallow bottom 11a, as compared with the structure having no shallow bottom 11a, since it is possible to quickly put rate of the molten slag 4 or coagulation slag lumps 4a, it can shorten the time to open the furnace during the slag on. Therefore, time is also longer capable of maintaining a reducing atmosphere in a sealed state in the furnace, there is also an effect that is raised reduction rate.
[0037]
　Depending shallow bottom part 11a of the furnace bottom 11, the mixing of the molten iron layer 6 in the molten slag 4 and the electric furnace 1, even if they are suppressed by the molten slag layer 5 (T.Fe) to increase slag at the interface of the molten slag layer 5 and the molten iron layer 6 is reacted with C in the molten iron to generate CO gas, there is a case where it induces slag foaming. By placing the carbonaceous material powder from the reduction material injection nozzle 33 in which case, through the defoaming and reduction of forming slag, the forming can be sedated.
[0038]
　In addition, the furnace wall 12, preferably a tapping port 17 for discharging the reducing slag, a tap hole 18 for discharging molten iron is provided. Dekasuguchi 17, the position corresponding to the molten slag layer 5, specifically formed at a position higher than the highest height of the shallow bottom portion 11a, the tap hole 18 is formed at a position corresponding to the molten iron layer 6.
[0039]
　Next, a second embodiment will be described with reference to FIG.
　The second embodiment differs from the first embodiment in that the electric furnace was tilted furnace.
　In the second embodiment, elements having the same functions as those of the first embodiment are denoted by the same numerals, and a description will be given mainly the differences from the first embodiment.
[0040]
　As shown in FIG. 6, an electric furnace 1a according to the second embodiment is tilting furnace.
　Electric furnace 1a includes a tilt (not shown) to tilt the electric furnace 1a portion of the furnace wall 12, which is positioned higher than the deep bottom 11d, a tapping port 17 for discharging molten slag 4 by tilting, Dekasuguchi in the position facing the 17, provided on the extension of the deep bottom 11d, having a furnace bottom tap hole 18a for discharging the molten iron in the molten iron layer 6 by tilting.
　Thus, the electric furnace 1 may be a tilting furnace.
[0041]
　Next, a third embodiment will be described with reference to FIG.
　The third embodiment, in the second embodiment in that the furnace lid 13, and movable between the side of the upper end and the furnace wall 12 of the furnace wall 12.
　In the third embodiment, elements having the same functions as those of the first embodiment are denoted by the same numerals, will be described mainly the differences from the first embodiment.
[0042]
　As shown in FIG. 7, an electric furnace 1a according to the third embodiment, between the side of the upper end and the furnace wall 12 of the furnace wall 12 furnace lid 13 is movable in the direction B in FIG. 7 . The movement locus of the furnace roof 13 may be linear, may be arcuate. Moving track arcuate furnace lid 13 is a so-called swivel furnace lid.
　In a state where the furnace roof 13 is located at the upper end of the furnace wall 12, the interior of the electric furnace 1 as in FIG 2 is sealed.
　In a state where the furnace roof 13 is moved to the side of the furnace wall 12, an open part is formed above the furnace wall 12 as shown in FIG. 7, the opening portion serves as slag inlet 14.
　Thus, the slag charging port 14 is not necessarily provided in the furnace lid 13, by moving the furnace lid 13 relative to the furnace wall 12 may be formed an opening and the slag charging port 14.
Example
[0043]
　Hereinafter, a detailed explanation of the present invention based on examples, the present invention is not limited to the examples.
[0044]
　(Simulation)
　using first universal fluid analysis software FLUENT (R), by injecting a molten slag 4 in an electric furnace of the following conditions to observe its behavior from the axial sectional direction of the furnace.
　Furnace volume: 13.8 m 3
　reactor bottom area (S 1 + S 2 ): 7.5 m 2
　furnace slag viscosity: 0.25 Pa · s
　injection Slag Viscosity: 1.0 Pa · s
　Molten viscosity: 0.006 Pa · s
　Shallow the height of the bottom (H): 250 mm
　area of the shallow bottom portion (S 2 ): 1.1 m 2
　or hot water: 1.4 m 3
　injection slug flow width: 500 mm
　slag infusion rate: 1t / min, 5t / min , 10t / min, 20t / min
[0045]
　The results are shown in Figure 8.
　As shown in FIG. 8, if the slag infusion rate of 1t / min, does not reach the molten iron layer 6 mostly molten slag 4 which is injected even when the shallow portion 11a is not provided, injected slag and molten iron layer and the reaction was only slightly observed.
　Slag infusion rate is 5t / min, in the case of 10t / min, 20t / min, when there is no shallow bottom 11a was injected molten slag 4 reaches the molten iron layer 6, partially plunged into molten iron layer as to react with C in the molten iron is foreseen. In particular 10t / min, 20t / min, the reaction is violent, was found scattered mixed and the molten slag and molten iron.
　On the other hand, if there is shallow bottom 11a, slug injection rate even 10t / min, injected molten slag 4 is hardly react with molten iron layer 6, thus the molten iron and the mixture of molten slag 4 splashing also It was considered to be no.
　From this result, by providing the shallow bottom portion 11a, which is injected molten slag 4 is mixed with molten iron layer 6 it was found to be prevented from being violently react.
[0046]
(Example 1)
　Next, as the reducing reformer, an electric furnace 1 shown in FIGS. 2 to 5 were actual operation under the conditions shown in FIG. The specific procedure is as follows.
　First, as an electric furnace 1, a direct current electric furnace of the sealed stationary type furnace inner diameter of 6 m, a part of the water-cooled furnace lid, for introduction of molten slag 4 and the coagulation slag lumps 4a, the slug-on door 14a of the openable comprising, we were prepared which has a slag inlet 14.
　The electric furnace 1, directly under the slag charging port 14, the height from the hearth deepest portion is provided in the refractory of 450 mm, the shallow bottom portion 11a. The shape of the shallow portion 11a is in contact at one end to the furnace wall 12, furnace is refractory steel blocks rectangular. Area ratio in plan view of the shallow bottom part 11a against the furnace bottom was 10%. The furnace cover 13 is provided a duct 32 for exhaust gas discharge, and connecting the duct 32 to the combustible gas combustion cooling precipitator.
　The lower end of the tap hole 18 is at a height of 250mm from the furnace bottom innermost portion and the lower end of the tapping opening 17 was set to a height of 450mm from the hearth deepest portion.
　The point furnace residue (before slag on) are, [C] and 2.6% of molten iron 54 t, were molten slag 25t which is reduced to 1% (T.Fe).
[0047]
　Then, opening the slag-on door 14a, the molten slag 20t conveyed from the converter 4 ((T.Fe) 18% is) via a movable slag trough, into the furnace slag transport container 21 in 10 minutes, it was continuously charged into the electric furnace 1. Thus infusion rate becomes 2t / min on average. Slag is turned achieving suppression of reduction in response input power to 2MW, it was returned to 20MW after turning completion.
[0048]
　Before introduction of the molten slag 4, the level of the molten slag layer 5 that was the height of 630mm from the furnace bottom 11, in turned, but rose to the level of more than 1200 mm, though the slag on with short time of 10 minutes not, without causing bumping by mixing with molten iron layer 6, it was possible to complete the stably charged.
　From the start of feeding of the molten slag 4, it supplies the coke powder with 60 kg / min through a reducing agent injection nozzle 33 of the furnace lid 13 to complete the supply of coke powder 3.0t in 50 minutes from the feeding start of the molten slag 4.
[0049]
　After introduction of the molten slag 4, once it closed slag poured door 14a, 5t coagulation slag lumps 4a reopened after 5 minutes, were charged at once. Solidified slag lumps 4a is a slag solidified adhering to the slag-carrying container 21 at the time of turn-on of molten slag 4, maintained a 950 ° C.. Charged coagulation slag mass 4a is not in contact with the molten iron layer 6 is deposited on the shallow bottom portion 11a of the molten slag layer 5 in the furnace, it began to dissolve in the molten slag layer 5 over time.
　After introduction of coagulated slag mass 4a is quickly closed the slug-on door 14a, to ensure the sealing of the furnace was carried out slag reduction treatment with coke powder charged in a reducing gas atmosphere.
[0050]
　Through sedation time 10 minutes coke powder turned completed, the slag (T.Fe) after 60 minutes from the start slag charged could be reduced to 1% or less. It performs slag charged in a short time, then since a sealed furnace, it is possible to keep the furnace in a reducing atmosphere during reduction, presumably because reduction has progressed.
　During this time, the slag basicity ((CaO) / (SiO 2 a)), in order to reduce to 1.2 proper levels were 6.5t supplied sand from the reducing material injection nozzle 33.
　After a total process is completed, open the tapping port with an opening machine, a reduction slag 23t discharged outside of the furnace, and closed porosity in Maddogan.
[0051]
　Meanwhile, after charged with molten slag 4 into an electric furnace 1 at 10 min, where the solidification slag lumps 4a adhered to the slag-carrying container 21 is discharged to the earth floor, and weighed placed in slag lumps turned chute, about 6t met It was. The solidified slag lumps 4a while maintaining a high temperature, and it turned into an electric furnace 1 using a chute immediately after the next introduction of molten slag 4.
[0052]
　Repeat 5 times the operation, where the input amount of the molten slag 4 solidified slag lumps 4a reaches total 120t, and 27t discharging molten iron open the tap hole 18, leaving a Molten 54t in the furnace. Estimating the height of the tapping before the molten iron layer 6 was 440mm from the hearth 11, but after discharge was reduced to 300 mm.
[0053]
　From the above results, by using the electric furnace 1 having a shallow bottom 11a, without also causing the forming in a short time of slag on, since the reduction in a reducing atmosphere to seal the furnace after completion slag on, molten slag 4 and it was found that it is using the coagulation slag lumps 4a reducing modification.
[0054]
(Example 2)
　as a reducing reformer, using an electric furnace 1 shown in FIGS. 2-5, as shown in FIG. 10, was operated at different conditions as in Example 1. The specific procedure is as follows.
[0055]
　The 20t molten slag 4 of the first embodiment, while the continuously charged into an electric furnace 1 at 10 min, in the second embodiment, the 20t molten slag 4 continuously to the electric furnace 1 at 5 min input was. Therefore, the input speed is twice the first embodiment, the input time is half the first embodiment.
[0056]
　Before introduction of the molten slag 4, furnace slag level was at a height of about 630mm from the furnace bottom 11, turned end, due to rapidly increased to 1500mm or more levels, reduced material provided in two places of the furnace wall 12 from injection nozzle 33, yelling blown at 100 kg / min coke powder in the vicinity of the hot metal flow. As a result, the slag level began to descend, thereafter, since it was possible to complete the stable turned discontinued coke powder blown from the reducing agent injection nozzle 33 after 4 minutes.
[0057]
　Charged condition of coke powder from furnace lid 13, the input conditions for the solidification slag mass 4a is the same as in Example 1.
[0058]
　Through sedation time 15 minutes coke powder turned completed, the slag (T.Fe) after 60 minutes from the start of feeding of the molten slag 4 could be reduced to 1% or less. During this time, the slag basicity ((CaO) / (SiO 2 a)), in order to reduce to 1.2 proper levels were 6.5t supplied sand from the reducing material injection nozzle 33.
[0059]
　After a total process is completed, open the tapping port 17 with an opening machine, a reduction slag 23t discharged outside of the furnace, and closed porosity in Maddogan.
[0060]
　Meanwhile, after charged into the electric furnace 1 the molten slag 4 in 5 minutes, where the solidification slag lumps 4a adhered to the slag-carrying container 21 is discharged to the earth floor, and weighed placed in slag lumps turned chute, at about 6t there were. The solidified slag lumps 4a while maintaining a high temperature, and it turned into an electric furnace 1 using a chute immediately after the next molten slag on.
[0061]
　Repeat 5 times the operation, where the input amount of the molten slag 4 solidified slag lumps 4a reaches total 120t, and 27t discharging molten iron open the tap hole 18, leaving a Molten 54t in the furnace. Estimating the height of the tapping before the metal level was 440mm from the hearth 11, but after discharge was reduced to 300 mm.
[0062]
　From the above results, by using the electric furnace 1 having a shallow bottom 11a and reducing material injection nozzle 33, despite the slag on with as little as 5 minutes, while suppressing the forming, molten slag 4 and the coagulation slag it has been found that it is reducing reformed using a mass 4a.
[0063]
(Example 3)
　as the reducing reformer, as shown in FIG. 9 by using an electric furnace 1a shown in FIG. 6, was operated under the same conditions as in Example 1. The specific procedure is as follows.
[0064]
　First, provided as an electric furnace 1a, a direct current electric furnace of closed type tilting type furnace inner diameter of 6 m, a part of the water-cooled furnace lid, for molten slag 4 and the coagulation slag lumps 4a turned slag poured door 14a of the openable It was prepared what you are.
　The electric furnace 1a, directly under the slag charging port 14, provided with the shallow bottom part 11a of the refractory height 450mm from hearth deepest portion. The shape of the shallow portion 11a is in contact at one end to the furnace wall 12, furnace is refractory steel blocks rectangular. Area ratio in plan view of the shallow bottom part 11a against the furnace bottom 11 was 10%. Also the furnace cover 13 to duct 32 for exhaust gas discharge provided in addition to the slag charging port 14 was connected to a combustible gas fired cooling precipitator.
[0065]
　Furnace bottom tap hole 18a are tap holes for eccentric furnace bottom tapping (EBT, Eccentric Bottom Tapping). That is, in the hole of the electric furnace overhang portion bottom is immersed in molten iron at an electric furnace tilting, after tilting, starts tapping by opening the lid of the hole bottom. Following the metal emissions to closed by promptly stopper when the slag outflow is started. Then close the lid with the bottom of the hole, filling the filling sand furnace bottom tap hole 18a.
[0066]
　On the other hand, Dekasuguchi 17 is a furnace bottom tap hole 18a are on opposite sides, are provided with a Suragudoa not shown maintain the sealing property. Open Suragudoa during tapping, to discharge the molten slag 4 from the opening by tilting the electric furnace 1a.
[0067]
　The lower end of the tap hole 18 is at a height of 250mm from the furnace bottom level and the lower end of the tapping opening 17 was set from the furnace bottom to a height of 500 mm.
　The point furnace residue (before slag on) are, [C] and 2.6% of molten iron 54 t, were molten slag 25t which is reduced to 1% (T.Fe).
　Then, opening the slag-on door 14a of the furnace lid 13, was charged with molten slag 4 of 20t conveyed from the converter to the electric furnace 1a. Composition of the input conditions and slag were the same as in Example 1.
[0068]
　Before introduction of the molten slag 4, furnace slag level was from hearth deepest portion to the height of 630mm during on, it has been increased to a level in excess of 1200 mm, bumping by mixing with the molten slag 4 and molten iron layer 6 without also cause, it could be completed in a stable manner on.
　From the start of feeding of the molten slag 4, introduction of coke under the same conditions as in Example 1 through the reducing agent injection nozzle 33 of the furnace lid 13, introduction of coagulated slag lumps 4a, it was supplied quartz sand.
　Through sedation time 10 minutes coke powder turned completed, the slag (T.Fe) after 60 minutes from the molten slag charging start could be reduced to 1% or less.
　When the input amount of molten slag 4 and the coagulation slag lumps 4a reaches total 120t, the molten iron and 27t discharged by opening the furnace bottom outflow 18a, leaving Molten 54t in the furnace. Estimating the height of the tapping before the metal level was 450mm from the hearth 11, but after discharge was reduced to 300 mm.
[0069]
　From the above results, by using an electric furnace 1a having a shallow bottom 11a, also a tilting furnace, without causing slag foaming, it found that it is reduced reforming with molten slag 4 and the coagulation slag lumps 4a It was.
Industrial Applicability
[0070]
　According to the present invention, while maintaining the furnace atmosphere at a constant, to prevent generating a large slag foaming is mixed vigorously and molten iron layer of molten slag or solidified slag lumps and electric furnace immediately after turned on, the reduction it is possible to provide an electric furnace capable of high performance.
DESCRIPTION OF SYMBOLS
[0071]
1: Electric furnace
1a: electric furnace
4: molten slag
4a: solidification slag lumps
5: molten slag layer
6: molten iron layer
11: the furnace bottom
11a: shallow bottom
11d: deep bottom
12: furnace wall
13: furnace roof
14: Slag turned mouth
14a: slag-on door
15: upper electrode
16: furnace bottom electrode
17: Dekasuguchi
18: outflow
18a: tap hole
21: slag-carrying container
23: inclined gutter
32: duct
33: reducing agent injection nozzle

WE claims

A cylindrical furnace wall,
and the furnace lid provided at the upper end of the furnace wall,
　provided at a lower end of the furnace wall, and a deep bottom portion, the height relative to the deepest portion of the deep bottom 150mm or more, 500 mm or less in the region and the furnace bottom, having a shallow bottom is a
　an electric furnace having,
　wherein the electric furnace, directly from slag transport container, or the molten slag or solidified slag lumps through the inclined trough from the slag transport container slag charging port is provided which can be introduced,
　it said slag charging port has the overlap with the shallow bottom and plan view,
　the area ratio in plan view of the shallow bottom portion to the furnace bottom 5% or more, 40% or less and characterized in that an electric furnace.
[Requested item 2]
　The furnace lid or provided on both of the furnace lid and the furnace wall, and a reducing agent injection nozzle to inject reducing agent into the furnace,
　characterized in that it has an exhaust duct provided in the furnace lid, wherein electric furnace according to claim 1.
[Requested item 3]
　Said slag charging port is provided in the furnace lid, characterized in that it is covered with slag-on door closure, electric furnace according to claim 1 or claim 2.
[Requested item 4]
　Of the furnace wall, wherein provided at a position higher than the highest height of the shallow bottom part, and a tapping port for discharging the molten slag,
　the furnace wall, provided at a position lower than the shallow bottom part, out for discharging the molten iron and sprue,
　have,
　wherein the electric furnace is a stationary type, an electric furnace according to any one of claims 1 to 3.
[Requested item 5]
　A tilting unit for tilting the electric furnace,
　the furnace wall, which is positioned higher than the highest height of the shallow bottom part, and a tapping port for discharging the molten slag,
　provided on the extension of the deep bottom, molten iron a furnace bottom tap hole for discharging
　and having an electric furnace according to any one of claims 1 to 3.
[Requested item 6]
　The furnace lid is movable between the side of the upper end and the furnace wall of the furnace wall,
　said slag charging port is above the furnace wall while moving said furnace cover at the side of the furnace wall It characterized in that an open portion formed in an electric furnace according to claim 5.