CN114040987B - Electrolytic smelting furnace - Google Patents

Abstract

The electrolytic smelting furnace is provided with: a furnace main body into which iron ore is introduced; a furnace bottom electrode provided at the furnace bottom in the furnace main body; and a plurality of upper electrodes provided above the hearth electrode in the furnace body and having an electrode body for electrowinning the molten iron ore. At least one of the upper electrodes is a melting electrode having a heating portion for heating and melting iron ore to obtain molten iron ore inside the electrode body. This enables smooth start of operation of the electrolytic smelting furnace.

Description

Electrolytic smelting furnace

technical field

The invention relates to an electrolytic smelting furnace.

This application claims priority based on Japanese Patent Application No. 2019-115566 filed in Japan on June 21, 2019, and uses the content thereof here.

Background technique

As a technique for refining, for example, iron ore, heat treatment in a blast furnace or a converter has been widely used so far. In this method, iron ore as a metal material and coke as a reducing material are burned in a furnace. In the furnace, carbon contained in coke deprives iron of oxygen to generate heat, carbon monoxide, and carbon dioxide. The heat of reaction melts the iron ore to produce pig iron. After that, oxygen and impurities are removed from the pig iron to obtain pure iron.

Here, since the above-mentioned method requires a large amount of carbon including coke, the amount of generation of carbon monoxide and carbon dioxide increases. With the tightening of air pollution measures in recent years, refining techniques for suppressing the generation of these carbon-containing gases have been sought. As an example of such a technique, the electrolytic smelting method described in the following patent document 1 is mentioned.

In the electrolytic smelting method, a voltage is applied inside a furnace having a planar furnace bottom with molten iron ore interposed between a furnace bottom electrode and an upper electrode. As a result, molten electrolyte including slag components is deposited on the upper electrode side, and molten iron (pure iron) is deposited on the furnace bottom electrode side. As the upper electrode, for example, metal materials including iron, chromium, vanadium, and tantalum are used. As shown in FIG. 21 , conventionally, the upper electrodes T are generally in the shape of rods extending in the vertical direction, and are arranged in a grid pattern at intervals in the horizontal plane. As the bottom electrode, a metal material made of molybdenum is used as an example.

prior art literature

patent documents

Patent Document 1: Specification of US Patent No. 8764962

Contents of the invention

The problem to be solved by the invention

However, in the above-mentioned electrolytic smelting method, the amount of heat radiation passing through the wall surface of the furnace becomes large. In addition, since iron ore before melting is not electrified, electrodes for electrolytic smelting cannot be used. Therefore, it may be difficult to uniformly melt the iron ore charged into the furnace when refining is started. As a result, the smooth operation of the electrolytic smelting furnace began to be hindered.

This invention was made in order to solve the said subject, and it aims at providing the electrolytic smelting furnace which can start operation smoothly.

Solution to the problem

An electrolytic smelting furnace according to one aspect of the present invention includes: a furnace main body into which iron ore is introduced; a furnace bottom electrode provided on the bottom of the furnace main body; and a plurality of upper electrodes provided on the furnace main body. Above the bottom electrode in the furnace, at least one of the upper electrodes is an electrode for melting with an electrode for electrolytic smelting and a heating part, and the electrode for electrolytic smelting is energized with the bottom electrode to melt The iron ore is subjected to electrolytic smelting, and the heating unit is provided inside the electrode for electrolytic smelting to heat and melt the iron ore to obtain the molten iron ore.

According to the above configuration, the iron ore can be heated and melted by the heating portion of the melting electrode before electrolytic smelting. Thereby, molten iron ore can be produced|generated easily. Furthermore, since the heating portion is provided inside the electrode for electrolytic smelting, the size of the electrode for melting can also be suppressed to be small. Accordingly, it is possible to further increase the degree of freedom in the arrangement of the upper electrode.

In the above-mentioned electrolytic smelting furnace, the heating unit may include: a cylindrical torch body disposed on the inner peripheral surface of a through hole formed in the electrolytic smelting electrode; and a plasma torch electrode inserted through The iron ore is melted by a plasma stream formed by passing electricity between the torch body and the plasma torch electrode in a state before the iron ore is melted on the inner peripheral side of the torch body. .

According to the above configuration, the plasma flow is formed by passing electricity between the torch main body and the plasma torch electrode in the state before the iron ore is melted. Iron ore can be efficiently melted by this plasma flow.

In the above-mentioned electrolytic smelting furnace, the heating unit may be heated by a plasma stream formed by passing electricity between the plasma torch electrode and the furnace bottom electrode in a state where the iron ore has started to melt. The molten iron ore is heated.

According to the above configuration, the plasma flow is formed by passing electricity between the plasma torch electrode and the furnace bottom electrode in a state where the iron ore has started to melt. The iron ore that has started to melt can be further melted by this plasma flow, thereby achieving high temperature and homogenization. In addition, even when the molten iron ore is solidified due to the interruption of work, for example, it can be melted again by the heating unit. Accordingly, the electrolytic smelting operation can be restarted immediately.

In the electrolytic smelting furnace described above, the electrolytic smelting furnace may further include: a power supply unit for refining, which applies a voltage between the furnace bottom electrode and the upper electrode; The refining power supply unit is provided independently, and applies a voltage between the furnace bottom electrode and the plasma torch electrode.

Here, the voltage required at the start of operation (that is, when iron ore is melted) is larger than that at the time of refining. According to the above configuration, the power supply unit for refining and the power supply unit for starting are provided independently. Therefore, for example, compared with a configuration in which the refining power supply unit and the starting power supply unit are not independent, fluctuations in the voltage generated by each power supply unit can be suppressed. Accordingly, the electrolytic smelting furnace can be operated more stably.

In the above electrolytic smelting furnace, the heating unit may melt the iron ore with a flame of a mixed gas containing hydrogen in a state before the iron ore is melted.

According to the above configuration, the molten ore can be heated easily and rapidly by supplying the combustion gas containing hydrogen from the cylindrical pipe and forming a flame from the combustion gas.

In the above-mentioned electrolytic smelting furnace, the heating unit may supply a mixed gas containing hydrogen to the molten iron ore by extinguishing the flame in the state where the iron ore has started to melt, thereby heating the Molten iron ore is stirred.

According to the above configuration, the molten iron ore can be stirred by supplying the mixed gas for melting the iron ore to the molten iron ore in a flame-extinguished state. Thereby, molten iron ore can be homogenized. In addition, since there is no need to provide a dedicated device for stirring, the structure of the device can be simplified. Thereby, manufacturing cost and operating cost can be reduced.

In the above-mentioned electrolytic smelting furnace, at least one of the upper electrodes may be formed with a charging hole, and the charging hole penetrates the upper electrode in the vertical direction to introduce the iron ore into the furnace main body. stone.

According to the above configuration, iron ore can be smoothly charged into the furnace main body through the charging hole. In addition, since the input hole is formed in a part of the upper electrode, the number of upper electrodes and the density of installation can be increased compared to the case where an input port for inputting iron ore is separately provided.

In the above-mentioned electrolytic smelting furnace, the furnace main body may further include: a discharge recess that is further recessed downward from the furnace bottom; a discharge path that communicates the discharge recess with the outside; and an opening and closing part, which opens and closes the discharge passage.

According to the above configuration, molten iron produced by electrolytic smelting can be easily taken out of the furnace main body through the discharge recess and the discharge path. In particular, since the opening and closing part is provided in the discharge path, the molten iron can be taken out more easily only by opening the opening and closing part.

In the above-mentioned electrolytic smelting furnace, the discharge passage may be provided above the bottom surface of the discharge recess, and a part of the discharge recess below the discharge passage may be provided with a The outer peripheral heating device covers the lower part.

According to the above configuration, since the discharge path is provided above the bottom surface of the discharge recess, components containing impurities settle on the bottom surface side, and only components not containing impurities can be taken out through the discharge path. And, the part below the discharge path is covered from the outside by the peripheral heating device. Therefore, for example, the component solidified in the discharge recess when the work is interrupted can be immediately melted when the work is resumed. Thereby, the electrolytic smelting furnace can be operated more smoothly.

In the above-mentioned electrolytic smelting furnace, the electrolytic smelting furnace may further include a discharge passage heating unit, the discharge passage heating unit is provided in the discharge passage, and the molten iron ore circulating in the discharge passage Stone, or a conductive refractory material that forms a flow path, is heated to change the viscosity.

According to the above configuration, the viscosity of the molten iron ore is changed by heating the molten iron ore flowing through the discharge path or the conductive refractory material forming the flow path by the discharge path heating unit. Accordingly, the fluidity of the molten iron ore changes, and the flow rate can be adjusted to a desired value.

In the above-mentioned electrolytic smelting furnace, the electrolytic smelting furnace may also include: a slag discharge passage, which penetrates the side wall of the furnace main body; and a slag discharge passage heating part, which is arranged on the The slag flowing through the slag discharge path or the conductive refractory material forming the flow path is heated to change the viscosity.

According to the above configuration, the viscosity of the slag is changed by heating the slag flowing through the slag discharge passage or the conductive refractory material forming the flow passage by the slag discharge passage heating unit. Accordingly, the fluidity of the slag changes, and the flow rate can be adjusted to a desired value.

In the above-mentioned electrolytic smelting furnace, the furnace main body may further include an input portion for introducing the iron ore input from the outside into the furnace main body, and the furnace bottom may From the input portion to the discharge recess, the height position changes downward.

According to the above configuration, the height position of the furnace bottom changes downward from the input portion toward the discharge concave portion. Thereby, molten iron ore and reduced molten iron can be made to flow naturally toward the discharge recessed part. As a result, molten iron can be taken out more easily.

In the above-mentioned electrolytic smelting furnace, the discharge path may be provided on the bottom surface of the discharge recess, and the furnace main body may further include a stirring gas supply part, and the stirring gas supply part may be directed upward from the bottom surface. Gas is supplied to the molten iron ore.

According to the above configuration, the molten iron ore and the reduced molten iron in the discharge recess can be stirred by the stirring gas supply unit. Thereby, molten iron ore and molten iron can be further homogenized.

In the above-mentioned electrolytic smelting furnace, the electrolytic smelting furnace may further include an auxiliary heating part, the auxiliary heating part is provided at least one of the upper part and the lower part of the main body of the furnace, and the molten iron ore Keep warm.

According to the above configuration, by providing the auxiliary heating portion, the molten iron ore in the furnace main body can be maintained in a molten state without being solidified.

In the electrolytic smelting furnace described above, the electrolytic smelting furnace may further include: a separation distance detection unit that detects the separation distance between the upper electrode and the upper surface of the molten iron ore; and an electrode moving unit , which moves the upper electrode vertically so that the separation distance becomes a predetermined constant value.

Here, in order to stably perform electrolytic smelting, it is necessary to keep the voltage applied between the upper electrode and the upper surface of the molten iron ore as constant as possible. On the other hand, as the electrolytic smelting proceeds, the reduced molten iron increases, and the upper surface of the molten iron ore moves upward. In addition, the voltage between the upper electrode and the upper surface of the molten iron ore depends on the separation distance between the two. According to the above configuration, the upper electrode can be moved by the electrode moving part so that the separation distance between the upper electrode and the upper surface of the molten iron ore becomes constant. Accordingly, the voltage applied between the upper electrode and the molten iron ore can be kept constant. As a result, electrolytic smelting can be performed more stably.

It is also possible that the above-mentioned electrolytic smelting furnace further includes: a chamber, which forms a space inside; and a vacuum pump, which makes the space into a vacuum state, and is formed on the upper electrode to penetrate the upper electrode in the vertical direction, and A through hole communicating with the space.

According to the above configuration, the slag can be sucked into the chamber in a vacuum state through the through-hole formed in the upper electrode. Thereby, slag and molten iron can be separated more easily.

In the above-mentioned electrolytic smelting furnace, the electrolytic smelting furnace may further include a downgas supply unit that supplies gas between the upper electrodes from above to make the upper electrodes The iron ores floating among each other settle.

Here, it is known that during electrolytic smelting, iron ore gradually becomes finer along with melting and floats near the liquid surface. According to the above configuration, the iron ore floating between the upper electrodes can be settled by the settling gas supply unit. Thereby, molten iron ore can be further homogenized.

In the above-mentioned electrolytic smelting furnace, the electrolytic smelting furnace may further include a sinking mechanism part, and the sinking mechanism part is provided between the upper electrodes and moves forward and backward toward the inside of the furnace body, so that The iron ore floating between the upper electrodes settles.

Here, it is known that during electrolytic smelting, iron ore gradually becomes finer along with melting and floats near the liquid surface. According to the above configuration, the iron ore floating between the upper electrodes can be settled by the settling mechanism part. Thereby, molten iron ore can be further homogenized.

In the above-mentioned electrolytic smelting furnace, at least one of the electrodes for melting may be formed with a peripheral input portion for introducing the iron ore into the peripheral portion of the furnace main body, and the electrolytic smelting furnace may further include a settling mechanism part, which is provided between the upper electrodes and moves forward and backward toward the inside of the furnace body to settle the iron ore floating between the upper electrodes. The peripheral heating part is provided separately from the furnace bottom electrode and the upper electrode, and heats and melts the iron ore introduced from the peripheral input part.

Here, in the peripheral portion inside the furnace main body, since heat diffuses to the outside through the wall surface of the furnace main body, melting of iron ore may be difficult to progress in comparison with other regions. According to the said structure, iron ore can be supplied to the peripheral edge part in a furnace main body through a peripheral edge input part. Furthermore, the iron ore can be heated and melted by the peripheral heating portion. Thereby, homogenization of molten iron ore in a furnace main body can be further promoted.

An electrolytic smelting furnace according to one aspect of the present invention includes: a furnace main body into which iron ore is introduced; a furnace bottom electrode provided on the bottom of the furnace main body; and a plurality of upper electrodes provided on the furnace main body. Above the inner furnace bottom electrode, the furnace main body is provided with: a discharge recess, which is further recessed downward from the furnace bottom; a discharge path, which communicates the discharge recess with the outside; and an opening and closing part, which The discharge path is opened and closed.

According to the above configuration, molten iron produced by electrolytic smelting can be easily taken out of the furnace main body through the discharge recess and the discharge path. In particular, since the opening and closing section is provided in the discharge path, molten iron can be taken out more easily just by opening the opening and closing section.

Invention effect

According to the present invention, it is possible to provide an electrolytic smelting furnace capable of smoothly starting operation.

Description of drawings

FIG. 1 is a cross-sectional view showing the structure of an electrolytic smelting furnace according to a first embodiment of the present invention.

Fig. 2 is a plan view showing the structure of the electrolytic smelting furnace according to the first embodiment of the present invention.

Fig. 3 is a cross-sectional view showing the structure of the plasma torch according to the first embodiment of the present invention, showing a state before iron ore is melted.

4 is a cross-sectional view showing the structure of the plasma torch according to the first embodiment of the present invention, and shows a state where iron ore has started to melt.

5 is an enlarged cross-sectional view of a melting electrode according to a second embodiment of the present invention, showing a state before iron ore is melted.

6 is an enlarged cross-sectional view of a melting electrode according to a second embodiment of the present invention, showing a state where iron ore has started to melt.

7 is an enlarged cross-sectional view of a melting electrode according to a third embodiment of the present invention.

8 is an enlarged cross-sectional view of a melting electrode according to a fourth embodiment of the present invention.

Fig. 9 is a cross-sectional view showing the structure of a furnace main body according to a fifth embodiment of the present invention.

Fig. 10 is an explanatory diagram showing the configuration and power system of an electrolytic smelting furnace according to a sixth embodiment of the present invention.

Fig. 11 is a cross-sectional view showing the structure of an electrolytic smelting furnace according to a seventh embodiment of the present invention.

12 is a cross-sectional view showing a modified example of the electrolytic smelting furnace according to the seventh embodiment of the present invention.

13 is a cross-sectional view showing the structure of an electrolytic smelting furnace according to an eighth embodiment of the present invention.

14 is a cross-sectional view showing the configuration of a discharge passage heating unit and a slag discharge passage heating unit according to an eighth embodiment of the present invention.

15 is an enlarged cross-sectional view of main parts showing the structure of an electrolytic smelting furnace according to a ninth embodiment of the present invention.

16 is an enlarged cross-sectional view of main parts showing the structure of a melting electrode according to a tenth embodiment of the present invention.

17 is an enlarged cross-sectional view of main parts showing a modified example of the melting electrode according to the tenth embodiment of the present invention.

Fig. 18 is a cross-sectional view showing the structure of an electrolytic smelting furnace according to an eleventh embodiment of the present invention.

Fig. 19 is an explanatory diagram showing the configuration and power system of an electrolytic smelting furnace according to a twelfth embodiment of the present invention.

Fig. 20 is an explanatory view showing a modified example of the electrolytic smelting furnace according to the twelfth embodiment of the present invention.

FIG. 21 is a plan view showing an example of a conventional upper electrode arrangement.

Detailed ways

[first embodiment]

A first embodiment of the present invention will be described with reference to FIGS. 1 to 4 . In the present embodiment, the electrolytic smelting furnace 100 is a device for melting iron ore and refining the molten iron ore by electrolytic reaction. It should be noted that the ore to be refined is not limited to iron ore, and any mineral resource can be applied to the electrolytic smelting furnace 100 as long as it is an ore that can be refined by an electrolytic reaction. In addition, instead of iron ore, iron scrap may be used as a target for smelting.

As shown in FIG. 1 , the electrolytic smelting furnace 100 has a furnace main body 10 , a furnace bottom electrode 11 , an upper electrode 12 , a collector electrode 13 , and a casing 14 .

The furnace main body 10 is a container having a bottom 10B extending in a horizontal plane. Iron ore is introduced into the furnace main body 10 . Iron ore is melted and heated in the furnace main body 10 to become molten ore Wm. The temperature of the molten ore Wm is determined based on the melting point of the material itself. As an example, the temperature of molten ore Wm is 1200-2000 degreeC. More preferably, the temperature is 1400 to 1700°C. Most preferably, the temperature of the molten ore Wm is 1500 to 1600°C.

A furnace bottom electrode 11 is provided on the bottom 10B of the furnace main body 10 . As an example, the furnace bottom electrode 11 has a plate shape integrally formed of a metal material mainly composed of molybdenum.

A plurality of upper electrodes 12 are arranged inside the furnace main body 10 and above the furnace bottom electrode 11 . As shown in FIG. 2 , the plurality of upper electrodes 12 are arranged at equal intervals in the horizontal direction in a grid pattern. As an example, the upper electrode 12 is formed as a cylindrical electrode body integrally formed of a metal material including iron, chromium, vanadium, and tantalum.

All the upper electrodes 12 and the furnace bottom electrodes 11 are energized, thereby performing electrolytic smelting of the molten iron ore. At least one of these upper electrodes 12 has a plasma torch 20 (heating unit) built into the upper electrode 12 , that is, the electrode main body, and serves as a melting electrode 12A capable of melting iron ore. In the example of FIG. 2 , among the upper electrodes 12 , a plurality of melting electrodes 12A are arranged at intervals in the horizontal direction. It should be noted that the arrangement of the upper electrode 12 is not limited to this, and may be appropriately changed according to design and specifications.

As shown again in FIG. 1 , a collector electrode 13 is embedded in the bottom portion 10B of the furnace main body 10 and below the furnace bottom electrode 11 . The collector electrode 13 is formed of a conductive material, and one end thereof is electrically connected to the furnace bottom electrode 11 . It should be noted that, in the example of FIG. 1 , an example in which two collector electrodes 13 are provided is shown, but the number of collector electrodes 13 is not limited to two.

The furnace main body 10 , the furnace bottom electrode 11 , the upper electrode 12 , and the collector electrode 13 are covered by a casing 14 from the outside.

Next, the configuration of the melting electrode 12A provided with the plasma torch 20 for melting iron ore will be described with reference to FIGS. 3 and 4 . As shown in FIG. 3 , the melting electrode 12A has a cylindrical shape extending in the vertical direction. That is, the through-hole 12S extending in the vertical direction is formed inside (inner peripheral side) of the melting electrode 12A. The plasma torch 20 as a heating part for heating and melting the iron ore introduced into the furnace main body 10 is provided in the through hole 12S. The plasma torch 20 has a cylindrical torch main body 21 arranged on the inner peripheral surface of the through hole 12S, and a plasma torch electrode 22 inserted through the inner peripheral side of the torch main body 21 .

The torch main body 21 has a large-diameter portion 21L located on the side away from the furnace bottom electrode 11 (that is, the upper side), a small-diameter portion 21S coaxial with the large-diameter portion 21L and located below, and the large-diameter portion 21L and the small-diameter portion 21S. The connection part 21C connected in the up-down direction. The inner diameter of the large-diameter portion 21L is larger than the inner diameter of the small-diameter portion 21S. In addition, the inner diameter of the connecting portion 21C gradually decreases from above to below.

The plasma torch electrode 22 is arranged on the inner peripheral side of the large-diameter portion 21L. The plasma torch electrode 22 is formed in a rod shape having an outer diameter smaller than an inner diameter of the large-diameter portion 21L. Therefore, a gap as a flow path F is formed between the outer peripheral surface of the plasma torch electrode 22 and the inner peripheral surface of the large-diameter portion 21L. In this flow path F, the working gas supplied from the outside flows from above to below. The working gas is usually Ar, N2, etc., but a flammable gas (such as hydrogen) can also be preferably used. And, between the torch main body 21 and the plasma torch electrode 22, a voltage is applied by a power source. Based on such a voltage, electricity is passed between the torch main body 21 and the plasma torch electrode 22 to ionize the working gas to form a high-temperature plasma flow J1. The plasma stream J1 is ejected from below the plasma torch 20 toward the furnace bottom electrode 11 side.

In the electrolytic smelting furnace 100 configured as described above, first, the iron ore M is charged into the furnace main body 10 . This iron ore M needs to be melted before electrolytic smelting. Therefore, in the present embodiment, in the state before the iron ore M is melted, electricity is passed between the above-mentioned torch main body 21 and the plasma torch electrode 22 to form the plasma flow J1. Under the effect of the thermal energy of the plasma flow 11, the iron ore M starts to be heated and melted.

In the state where the iron ore M starts to melt, the operation of the above-mentioned plasma torch 20 is changed. Specifically, as shown in FIG. 4 , in this state, electricity is passed between the plasma torch electrode 22 and the furnace bottom electrode 11 . Thereby, a plasma flow J2 is formed between the torch main body 21 and the furnace bottom electrode 11 . The whole iron ore M which started to melt is melted by the heat energy of this plasma flow J2, and molten iron ore Wm is formed.

Next, electrolytic smelting is performed on the molten iron ore Wm. Specifically, a DC voltage is applied such that the upper electrode 12 is on the positive side and the collector electrode 13 is on the negative side. Electrolysis reaction (reduction reaction) proceeds by this voltage, and ferric oxide (Fe ₂ O ₃ ) contained in the molten ore Wm is reduced. As the reduction reaction progresses, molten iron Wf (pure iron) precipitates, and the molten iron Wf precipitates toward the furnace bottom electrode 11 side due to its own weight. Due to the increase in the amount of precipitation of the molten iron Wf, the molten iron Wf itself functions as a cathode-side terminal in addition to the furnace bottom electrode 11 .

On the other hand, oxygen is generated on the upper electrode 12 side.

As described above, according to the above configuration, the iron ore M can be heated and melted by the plasma torch 20 of the melting electrode 12A before electrolytic smelting. Thereby, molten iron ore Wm can be produced|generated easily. Thereby, the operation start of the electrolytic smelting furnace 100 can be started smoothly.

Furthermore, since the plasma torch 20 is provided inside the melting electrode 12A, the size of the melting electrode 12A can be kept small. Accordingly, it is possible to further increase the degree of freedom in the arrangement of the upper electrode 12 including the melting electrode 12A.

And, according to the above-mentioned structure, in the state before the iron ore M is melted, the plasma flow J1 is formed by passing electricity between the torch main body 21 and the plasma torch electrode 22 . The iron ore M can be efficiently melted by this plasma flow J1.

Moreover, according to the said structure, another plasma flow J2 is formed by energizing between the plasma torch electrode 22 and the furnace bottom electrode 11 in the state which melted the iron ore M. The iron ore M which has started to melt can be more efficiently melted and homogenized by this plasma flow J2. In addition, even when the molten iron ore Wm is solidified due to, for example, interruption of work, it can be melted again by the plasma torch 20 . Accordingly, the electrolytic smelting operation can be restarted immediately.

The first embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Second Embodiment]

Next, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6 . In addition, the same code|symbol is attached|subjected to the same structure as said 1st Embodiment, and detailed description is abbreviate|omitted. As shown in Fig. 5, in this embodiment, the structure of the heating unit 20' is different from that of the first embodiment described above. The burner 20' serving as a heating portion ejects gas (mixed gas Gh) into the furnace main body 10 through the through-hole 12S formed in the above-mentioned melting electrode 12A. As the mixed gas Gh, specifically, a gas containing hydrogen and an inert gas (hydrogen as an example) is used. The mixed gas Gh is supplied from the hydrogen supply unit 23 provided outside the furnace main body 10 to the above-mentioned through hole 12S. Furthermore, in the present embodiment, an ignition device 12I for igniting the air-fuel mixture is provided on the inner peripheral surface of the through hole 12S. In addition, as the inert gas, a rare gas other than the above-mentioned hydrogen can be appropriately selected and used.

The burner 20' ignites the above-mentioned mixed gas Gh in a state before the iron ore M is melted to form a flame Fh extending toward the furnace bottom electrode 11 (that is, extending downward from the through hole 12S). Under the action of the flame Fh, the iron ore M starts to melt.

In the state where the iron ore M starts to melt, the operation of the above-mentioned burner 20' is changed. Specifically, as shown in FIG. 6 , in this state, the burner 20' extinguishes the above-mentioned flame Fh to spray only the mixed gas Gh toward the molten iron ore Wm. Thereby, molten iron ore Wm is stirred. It should be noted that the extinguishment of the flame Fh is performed by changing the condition of the hydrogen mixture gas, changing to Ar gas, or the like. In addition, in a state where the burner 20' is turned off, additional iron ore may be added through the through hole 12S. And, when stirring, the upper electrode 12 is in a state of being in contact with the liquid surface of the molten iron ore Wm or being immersed below the liquid surface.

According to the above configuration, the iron ore M can be heated and melted easily and rapidly by the flame Fh of the mixed gas Gh containing hydrogen.

Furthermore, according to the above configuration, the molten iron ore Wm can be stirred by supplying the mixed gas Gh for melting the iron ore M to the molten iron ore Wm in a flame-off state. Thereby, molten iron ore Wm can be homogenized. In addition, since there is no need to provide a dedicated device for stirring, the structure of the device can be simplified. Thereby, manufacturing cost and operating cost can be reduced.

The second embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Third Embodiment]

Next, a third embodiment of the present invention will be described with reference to FIG. 7 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 7 , in this embodiment, in addition to the structure described in the above-mentioned first embodiment, a power supply unit (power supply unit 31 for refining) that applies a voltage between the furnace bottom electrode 11 and the upper electrode 12 , and a power supply unit (power supply unit 32 for starting) that applies a voltage between the furnace bottom electrode 11 and the plasma torch electrode 22 are electrically independent from each other.

The refining power supply unit 31 has a refining wire 31L electrically connecting the furnace bottom electrode 11 and the melting electrode 12A, and a DC power supply P1 and a switch 31S provided on the refining wire 31L. The supply state of the electric power supplied from the DC power supply P1 is switched by opening and closing the switch 31S.

The starting power supply unit 32 has a starting wire 32L electrically connecting the furnace bottom electrode 11 and the plasma torch electrode 22 , and a power supply P2 and a switch 32S provided on the starting wire 32L. The supply state of the electric power supplied from the power supply P2 is switched by opening and closing the switch 32S.

Here, the voltage required at the start of operation (that is, when starting to melt the iron ore) is larger than that at the time of refining. According to the above configuration, the refining power supply unit 31 and the starting power supply unit 32 are provided independently. Therefore, compared with, for example, a configuration in which the refining power supply unit 31 and the starting power supply unit 32 are not independent of each other, fluctuations in voltage generated by each power supply unit can be suppressed. Thereby, the electrolytic smelting furnace 100 can be operated more stably.

The third embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Fourth embodiment]

Next, a fourth embodiment of the present invention will be described with reference to FIG. 8 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 8 , in this embodiment, an input hole 12H for inputting iron ore before melting is formed on an input electrode 12 ′ other than the above-mentioned melting electrode 12A in the upper electrode 12 . . The input hole portion 12H penetrates the input electrode 12' in the vertical direction. Devices (not shown), such as a hopper and a screw feeder, are provided above the injection hole part 12H. Iron ore before melting is introduced into the input hole portion 12H from the outside by these means, and is injected into the furnace main body 10 .

In addition, the input electrode 12' is provided with either one of the plasma torch 20 and the burner 20' as the heating portion described in the above-mentioned embodiments. That is, the above-mentioned injection hole portion 12H also serves as a flow path for gas used in these plasma torches 20 and burners 20'.

According to the above configuration, iron ore can be smoothly charged into the furnace main body 10 through the charging hole portion 12H. In addition, since the input hole portion 12H is formed in a part of the upper electrode 12, the number and density of the upper electrodes 12 can be increased compared to the case where an input port for inputting iron ore is separately provided. As a result, refining can be performed more stably.

The fourth embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention. For example, in the fourth embodiment described above, an example has been described in which all the upper electrodes 12 except the melting electrode 12A are the input electrodes 12'. However, only a part of the upper electrode 12 other than the melting electrode 12A may be used as the input electrode 12'.

[Fifth Embodiment]

Next, a fifth embodiment of the present invention will be described with reference to FIG. 9 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 9 , the electrolytic smelting furnace 200 of the present embodiment is further provided with a heater H as an auxiliary heating part in addition to the respective structures described in the above-mentioned first embodiment. The heater H is provided to keep the molten iron ore Wm stored in the furnace main body 10 warm and to maintain a molten state. The heater H is installed on at least one of the upper side and the lower side of the furnace main body 10 . In the example of FIG. 9, the structure which provided the 1st heater H1 above and provided the 2nd heater H2 below is shown.

More specifically, the first heater H1 has a plate shape that is opposed to each other at a distance above the furnace main body 10 . A plurality of openings h through which the above-mentioned upper electrode 12 is inserted are formed in the first heater H1. The second heater H2 is buried below the collector electrode 13 in the bottom portion 10B of the furnace main body 10 . The second heater H2 also has a plate shape similarly to the first heater H1.

According to the above configuration, by providing the heater H as the auxiliary heating portion, the molten iron ore in the furnace main body 10 can be maintained in a molten state without being solidified. Thereby, electrolytic smelting can be performed more stably.

The fifth embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Sixth embodiment]

Next, a sixth embodiment of the present invention will be described with reference to FIG. 10 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 10 , the electrolytic smelting furnace 300 of the present embodiment further includes a separation distance for detecting the separation distance L between the bottom surface of the upper electrode 12 (electrode bottom surface 12B) and the upper surface of the molten iron Wf (the molten iron surface Sw). The detection unit 41 and the electrode moving unit 42 move the upper electrode 12 in the vertical direction based on the value of the separation distance.

The separation distance detector 41 measures the current and voltage flowing between the upper electrode 12 and the furnace bottom electrode 11, and calculates the separation distance L based on the current characteristics and voltage characteristics. In addition, as mentioned above, separation distance L concerns the upper surface of molten iron Wf. In other words, the separation distance L is the thickness of the molten iron ore Wm located on the upper layer of the molten iron Wf. Here, when the separation distance L increases, the resistance increases due to the increase in the separation distance L. Therefore, as the separation distance L increases, the amount of current flowing between the upper electrode 12 and the furnace bottom electrode 11 decreases. That is, a change in the separation distance L can be detected by measuring the amount of current at a certain voltage value.

When a change in the separation distance L is detected by the separation distance detection unit 41 , the electrode moving unit 42 moves the upper electrode 12 vertically to adjust the separation distance L to a predetermined constant value. In addition, as the electrode moving part 42, various actuators, a motor, etc. are preferably used.

Here, in order to perform electrolytic smelting stably, it is necessary to keep the voltage applied between the upper electrode 12 and the molten iron surface Sw as constant as possible. On the other hand, as the electrolytic smelting proceeds, the reduced molten iron Wf increases, and the upper surface of the molten iron Wf (the molten iron surface Sw) moves upward. In addition, the voltage between the upper electrode 12 and the molten iron surface Sw depends on the distance between them. According to the above configuration, the upper electrode 12 can be moved by the electrode moving part 42 so that the separation distance L between the upper electrode 12 and the molten iron surface Sw becomes constant. Thereby, the voltage applied between the upper electrode 12 and the molten iron Wf can be kept constant. As a result, electrolytic smelting can be performed more stably.

The sixth embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Seventh Embodiment]

Next, a seventh embodiment of the present invention will be described with reference to FIG. 11 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 11 , in the electrolytic smelting furnace 400 of this embodiment, the furnace main body 10 ′ further includes a discharge recess 10H that is further recessed downward from the furnace bottom (bottom 10B), and a discharge port that communicates the discharge recess 10H with the outside. The passage 10E, the opening and closing unit 5 that switches the communication state by opening and closing the discharge passage 10E, and the outer peripheral heating device 6 that covers the inside of the discharge recess 10H from the outside.

The discharge recess 10H has a rectangular cross-sectional shape dented downward from the bottom 10B. The discharge path 10E is provided above the bottom surface of the discharge recess 10H (the discharge recess bottom 10S). In the discharge recess 10H, a portion below the discharge path 10E is provided with a peripheral heating device 6 for heating the portion. As the peripheral heating device 6, specifically, an IH heater or the like is preferably used.

According to the above configuration, the molten iron Wf produced by electrolytic smelting can be easily taken out of the furnace main body 10 through the discharge recess 10H and the discharge path 10E. In particular, since the opening/closing portion 5 is connected to the discharge path 10E, the molten iron Wf can be taken out more easily simply by opening the opening/closing portion 5 .

Furthermore, according to the above configuration, the discharge path 10E is provided above the bottom surface of the discharge recess 10H (the discharge recess bottom 10S). A portion below the discharge path 10E is covered from the outside by the peripheral heating device 6 . Therefore, for example, the component solidified in the discharge recess 10H when the work is interrupted can be melted immediately when the work is resumed. Accordingly, the electrolytic smelting furnace 400 can be operated more smoothly.

The seventh embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention. For example, instead of the structure of the seventh embodiment described above, a discharge path 10E' may be formed on the bottom surface 10S of the discharge recess as shown in Fig. 12 . In addition, in the example shown in the drawing, a stirring gas supply unit 7 is also provided for supplying hydrogen, Ar gas, etc. for stirring the molten iron Wf from the discharge recess bottom surface 10S toward the discharge recess 10H.

According to the above configuration, the molten iron Wf can be naturally taken out to the outside by gravity through the discharge path 10E'. Furthermore, the molten iron ore Wm and the molten iron Wf in the discharge recess 10H can be stirred by the stirring gas supply part 7 . Furthermore, the molten iron ore Wm and the molten iron Wf can be stirred by the electromagnetic stirring effect obtained by induction heating. Thereby, the temperature of the molten iron ore Wm and the molten iron Wf can be further uniformized and homogenized.

[Eighth Embodiment]

Next, an eighth embodiment of the present invention will be described with reference to FIGS. 13 and 14 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 13 , the electrolytic smelting furnace 500 of this embodiment is based on the scheme described in the above-mentioned seventh embodiment, and further includes a device for taking out the slag Ws generated in the main body 10 accompanying the progress of the furnace electrolytic smelting. The slag discharge passage 10F to the outside, the slag discharge passage heating part Hs for heating the slag Ws flowing through the slag discharge passage 10F, and the heating part Hs for heating the molten iron ore Wm flowing through the discharge passage 10E Discharge path heating part Hf.

The slag discharge path 10F penetrates the side wall of the furnace main body 10 . The slag discharge path 10F is formed at a position separated upward from the furnace bottom electrode 11 . The opening and closing part 5' which changes the opening and closing state of this slag discharge passage 10F is provided in the slag discharge passage 10F. The slag discharge passage heating unit Hs changes the viscosity (decreases the viscosity.) by heating the slag Ws flowing through the slag discharge passage 10F. Thereby, the discharge flow rate of the slag Ws can be adjusted.

The discharge path heating part Hf is provided similarly to the slag discharge path heating part Hs about the discharge path 10E. The discharge passage heating unit Hf changes the viscosity (decreases the viscosity.) by heating the molten iron ore Wm (molten iron Wf) flowing in the discharge passage 10E. Thereby, the discharge flow rate of molten iron ore Wm (molten iron Wf) can be adjusted.

As a specific example of these discharge path heating part Hf and the slag discharge path heating part Hs, the structure shown in FIG. 14 is preferably used. As shown in the figure, the high-frequency coil 51 serving as the discharge passage heater Hf and the slag discharge passage heater Hs is disposed so as to cover the outer periphery of the discharge passage 10E (or slag discharge passage 10F). Moreover, you may provide the plug 50 which moves back and forth inside and outside this discharge path 10E (or 10F of slag discharge paths). The opening and closing state of the discharge path 10E (or the slag discharge path 10F) can be changed by moving the plug 50 forward and backward.

According to the above configuration, the viscosity of the molten iron ore Wm changes by heating the molten iron ore Wm flowing through the discharge path 10E by the discharge path heating unit Hf. Accordingly, the fluidity of the molten iron ore Wm changes, and the flow rate can be adjusted to a desired value.

And, according to the above configuration, the viscosity of the slag Ws changes by heating the slag Ws flowing through the slag discharge path 10F by the slag discharge path heating unit Hs. Thereby, the fluidity of the slag Ws changes, and the flow rate can be adjusted to a desired value.

The eighth embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Ninth Embodiment]

Next, a ninth embodiment of the present invention will be described with reference to FIG. 15 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 15 , the electrolytic smelting furnace 600 of this embodiment further includes a chamber 60 in which a space V communicating with the through-hole 12S of the upper electrode 12 is formed, and air is sucked from the space V in the chamber 60 . The vacuum pump 61 is made into a vacuum state. The space V communicates with the upper end of the through-hole 12S. By making the space V into a vacuum state, the slag Ws is sucked into the space V through the through-hole 12S.

According to the above configuration, the slag Ws can be sucked into the vacuum chamber 60 (space V) through the through-hole 12S formed in the upper electrode 12 . Thereby, slag Ws and molten iron Wf can be separated more easily.

The ninth embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Tenth Embodiment]

Next, a tenth embodiment of the present invention will be described with reference to FIG. 16 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 16 , the electrolytic smelting furnace 700 of this embodiment further includes a downgas supply unit 70 . The sedimentation gas supply unit 70 supplies gas between the upper electrodes 12 from above to settle the iron ore M floating between the upper electrodes 12 . In addition, the sedimentation gas supply part 70 may be inserted in molten iron ore Wm, and may supply gas into molten iron ore Wm.

Here, it is known that during electrolytic smelting, iron ore M gradually becomes finer with melting, and these finer iron ore M float near the liquid surface of molten iron ore Wm. According to the above configuration, the iron ore M floating between the upper electrodes 12 can be settled by the settling gas supply unit 70 . In addition, by supplying gas into the molten iron ore, the floating iron ore can be engulfed in the molten iron ore. Thereby, molten iron ore Wm can be further homogenized.

The tenth embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention. For example, as shown in FIG. 17 , instead of the above-mentioned downgas supply unit 70, a structure including a settling mechanism section 70' may be adopted. The settling mechanism part 70' moves forward and backward between the upper electrodes 12 in the vertical direction. When the floating iron ore M is generated as described above, the settling mechanism part 70' can be moved downward to sink the iron ore M into the molten iron ore Wm. Thereby, molten iron ore can be further homogenized.

[Eleventh Embodiment]

Next, an eleventh embodiment of the present invention will be described with reference to FIG. 18 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in Fig. 18, in the electrolytic smelting furnace 800 of this embodiment, the structure of the furnace main body 10' is different from the above-mentioned respective embodiments. The furnace bottom B of the furnace main body 10' is configured such that its height position changes stepwise downward as it goes from the input portion 80 to the discharge recess 10H in the horizontal direction. That is, the height position of the furnace bottom B decreases stepwise from the central portion of the furnace main body 10' toward the peripheral portion. The central portion refers to a region including a portion through which the central axis O extending in the vertical direction passes, as shown in FIG. 18 .

More specifically, the hearth B has a first hearth B1 , a second hearth B2 , and a third hearth B3 arranged in order from the side away from the discharge recess 10H toward the discharge recess 10H. The second furnace bottom B2 is located below the first furnace bottom B1. The third hearth B3 is located below the second hearth B2. In addition, in the present embodiment, an example in which the height of the furnace bottom B changes in three steps is shown for the sake of simplicity of description, but the furnace bottom B may be divided into four or more heights.

According to the above structure, the height position of the furnace bottom B changes downward from the input part 80 toward the discharge recessed part 10H. Thereby, molten iron ore Wm and reduced molten iron Wf can be made to flow naturally toward discharge recessed part 10H. As a result, the molten iron Wf can be taken out more easily.

The eleventh embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention.

[Twelfth Embodiment]

Next, a twelfth embodiment of the present invention will be described with reference to FIG. 19 . In addition, the same code|symbol is attached|subjected to the same structure as each above-mentioned embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 19 , in the electrolytic smelting furnace 900 of the present embodiment, in the melting electrode 12A arranged along the side wall of the furnace main body 10 as at least one of the melting electrodes 12A, a The peripheral input portion 80 ′ of the melting electrode 12A is penetrated in the vertical direction. In addition, the electrolytic smelting furnace 900 further includes a peripheral heating portion 90 for heating and melting the iron ore M introduced from the peripheral input portion 80'.

The peripheral heating unit 90 has a pair of electrode terminals 91 and 91 provided separately from the above-mentioned furnace bottom electrode 11 and upper electrode 12 . The electrode terminals 91, 91 are immersed in the molten iron ore Wm (or molten iron Wf). A voltage is applied to the electrode terminals 91 and 91 by a power supply P. Thus, a Joule heating portion is formed between the electrode terminals 91 , 91 . As a result, when new iron ore is thrown into molten iron ore Wm, this iron ore is heated by the said Joule heating part, and melt|dissolves. In addition, it is preferable to provide the stirring gas supply part 70B in the vicinity of these electrode terminals 91 and 91 . The stirring gas supply unit 70B supplies gas to the molten iron ore Wm melted by the above-mentioned peripheral edge heating unit 90 to stir it.

Here, in the peripheral portion inside the furnace main body 10 , since heat diffuses to the outside through the wall surface of the furnace main body 10 , melting of iron ore may be difficult to progress compared to other regions. According to the above configuration, the iron ore can be supplied to the peripheral portion in the furnace main body 10 through the peripheral edge input portion 80', and the iron ore can be heated and melted by the peripheral edge heating portion 90. Thereby, temperature uniformity and homogenization of the molten iron ore Wm in the furnace main body 10 can be further promoted.

The twelfth embodiment of the present invention has been described above. It should be noted that various changes and modifications can be made to the above-mentioned structures without departing from the technical idea of the present invention. For example, the upper electrode 12 and the side electrode 92 embedded in the side wall of the furnace main body 10 may be provided as the peripheral heating portion 90' as shown in FIG. 20 . By forming the above-mentioned Joule heating portion between the upper electrode 12 and the side electrode 92 , the newly charged iron ore M can be melted.

Industrial availability

In the electrolytic smelting furnace according to one aspect of the present invention, operation can be started smoothly.

Explanation of reference signs:

100, 200, 300, 400, 500, 600, 700, 800, 900: electrolytic smelting furnace;

10, 10': Furnace body;

10B: bottom;

10E: discharge path;

10F: slag discharge path;

10H, 10H': Recess for discharge;

10S: the bottom surface of the concave part for discharge;

11: Furnace bottom electrode;

12: upper electrode;

12A: electrode for melting;

12A': electrode for input;

12B: electrode bottom surface;

12S: through hole;

12H: input hole;

12I: ignition device;

14: shell;

20: plasma torch;

20': burner;

21: torch main body;

21L: large diameter part;

21S: small diameter department;

21C: connection part;

22: Plasma torch electrode;

23: Hydrogen supply department;

31: Power supply unit for refining;

31L: Refining wire;

31S, 32S: switch;

32: Power supply unit for starting;

32L: wire for starting;

41: Separation distance detection unit;

42: Electrode moving part;

5, 5': opening and closing part;

50: stopper;

51: high frequency coil;

6: peripheral heating device;

60: chamber;

61: vacuum pump;

7, 70, 70', 70B: Stirring gas supply part;

80: input department;

80': peripheral input part;

90, 90': peripheral heating part;

91: electrode terminal;

92: side electrodes;

B: Furnace bottom;

B1: the first furnace bottom;

B2: second furnace bottom;

B3: the third furnace bottom;

F: flow path;

Fh: flame;

Gh: mixed gas;

h: opening;

H: heater;

H1: first heater;

H2: second heater;

Hf: discharge heating part;

Hs: Heating part of slag discharge path;

J1, J2: plasma flow;

M: iron ore;

P1: AC power supply;

P2: DC power supply;

Sw: molten iron level;

V: space;

Wm: molten iron ore;

Wf: molten iron;

Ws: slag.

Claims (19)

1. An electrolytic smelting furnace, wherein,

the electrolytic smelting furnace is provided with:

a furnace main body into which iron ore is introduced;

a furnace bottom electrode provided at a furnace bottom in the furnace main body;

a plurality of upper electrodes provided above the furnace bottom electrode in the furnace main body, and having an electrode main body for electrowinning molten iron ore; and

a settling gas supply unit configured to supply a gas from above to between the upper electrodes to settle the iron ores floating between the upper electrodes,

at least one of the upper electrodes is a melting electrode having a heating portion inside the electrode body, and the heating portion heats and melts the iron ore to obtain the molten iron ore.

2. An electrolytic smelting furnace, wherein,

the electrolytic smelting furnace is provided with:

a furnace main body into which iron ore is introduced;

a furnace bottom electrode provided at a furnace bottom in the furnace main body;

a plurality of upper electrodes provided above the furnace bottom electrode in the furnace main body, and having an electrode main body for electrowinning molten iron ore; and

a settling mechanism part which is provided between the upper electrodes and settles the iron ore floating between the upper electrodes by moving forward and backward in the furnace main body,

at least one of the upper electrodes is a melting electrode having a heating portion inside the electrode body, and the heating portion heats and melts the iron ore to obtain the molten iron ore.

3. The electrolytic smelting furnace according to claim 1 or 2,

the heating part has: a cylindrical torch body disposed on an inner peripheral surface of a through hole formed in the electrode body; and a plasma torch electrode inserted through an inner peripheral side of the torch body,

in a state before the iron ore is melted, the iron ore is melted by a plasma jet formed by passing electricity between the torch body and the plasma torch electrode.

4. The electrolytic smelting furnace according to claim 3,

the heating unit heats the molten iron ore by a plasma jet formed by applying electricity between the plasma torch electrode and the hearth electrode in a state where the iron ore starts to be molten.

5. The electrolytic smelting furnace according to claim 4,

the electrolytic smelting furnace further includes:

a refining power supply unit for applying a voltage between the hearth electrode and the upper electrode; and

and a starting power supply unit which is provided independently of the refining power supply unit and applies a voltage between the hearth electrode and the plasma torch electrode.

6. The electrolytic smelting furnace according to claim 1 or 2,

the heating section melts the iron ore by a flame formed of a mixed gas containing hydrogen in a state before the iron ore is melted.

7. The electrolytic smelting furnace according to claim 6,

the heating section extinguishes the hydrogen-containing mixed gas and supplies the oxygen-containing mixed gas to the molten iron ore in a state where the iron ore starts to be molten, thereby stirring the molten iron ore.

8. The electrolytic smelting furnace according to claim 1 or 2,

at least one of the upper electrodes is formed with a feed hole portion that penetrates the upper electrode in the vertical direction to introduce the iron ore into the furnace main body.

9. The electrolytic smelting furnace according to claim 1 or 2,

the furnace main body further includes:

a discharge recess that is recessed further downward from the furnace bottom;

a discharge passage that communicates the discharge recess with the outside; and

and an opening/closing unit that opens and closes the discharge path.

10. The electrowinning furnace in accordance with claim 9,

the discharge passage is provided above the bottom surface of the discharge recess, and an outer periphery heating device that covers the lower portion of the discharge recess from the outside is provided in the lower portion of the discharge passage.

11. The electrowinning furnace in accordance with claim 9,

the electrolytic smelting furnace further includes a discharge path heating unit that is provided in the discharge path and heats the molten iron ore or the electrically conductive refractory material forming the flow path, which flows through the discharge path, to change viscosity.

12. The electrolytic smelting furnace according to claim 9,

the electrolytic smelting furnace is further provided with:

a slag discharge passage that penetrates a side wall of the furnace main body; and

and a slag discharge path heating unit that is provided in the slag discharge path and changes viscosity by heating slag flowing through the slag discharge path or a refractory that has conductivity and forms a flow path.

13. The electrowinning furnace in accordance with claim 9,

the furnace main body further includes a charging portion that introduces the iron ore charged from outside into the furnace main body,

the furnace bottom changes in height downward as it goes from the input portion toward the discharge recess in the horizontal direction.

14. The electrolytic smelting furnace according to claim 9,

the discharge passage is provided on the bottom surface of the discharge recess,

the furnace main body further includes a stirring gas supply unit that supplies a gas from the bottom surface toward an upper direction of the molten iron ore.

15. The electrolytic smelting furnace according to claim 1 or 2,

the electrolytic smelting furnace is further provided with an auxiliary heating part which is arranged on at least one of the upper part and the lower part of the furnace main body and is used for preserving heat of the molten iron ore.

16. The electrolytic smelting furnace according to claim 1 or 2,

the electrolytic smelting furnace further includes:

a separation distance detecting unit that detects a separation distance between the upper electrode and an upper surface of the molten iron ore; and

and an electrode moving unit that moves the upper electrode in a vertical direction so that the separation distance is a predetermined constant value.

17. The electrowinning furnace in accordance with claim 1 or 2,

the electrolytic smelting furnace is further provided with:

a chamber having a space formed therein; and

a vacuum pump for making the space in a vacuum state,

the upper electrode is formed with a through hole penetrating the upper electrode in a vertical direction and communicating with the space.

18. An electrolytic smelting furnace, wherein,

the electrolytic smelting furnace is provided with:

a furnace main body into which iron ore is introduced;

a furnace bottom electrode provided at a furnace bottom in the furnace main body;

a plurality of upper electrodes disposed above the furnace bottom electrode in the furnace main body; and

a settling gas supply unit configured to supply a gas from above to between the upper electrodes to settle the iron ores floating between the upper electrodes,

the furnace main body is provided with:

a discharge recess which is recessed further downward from the furnace bottom;

a discharge passage for communicating the discharge recess with the outside; and

and an opening/closing unit that opens and closes the discharge path.

19. An electrolytic smelting furnace, in which,

the electrolytic smelting furnace is provided with:

a furnace main body into which iron ore is introduced;

a furnace bottom electrode provided at a furnace bottom in the furnace main body;

a plurality of upper electrodes disposed above the furnace bottom electrode in the furnace main body; and

a settling mechanism part which is provided between the upper electrodes and settles the iron ore floating between the upper electrodes by moving forward and backward in the furnace main body,

the furnace main body is provided with:

a discharge recess that is recessed further downward from the furnace bottom;

a discharge passage that communicates the discharge recess with the outside; and

an opening/closing unit that opens and closes the discharge path.

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