JP2000292069A - Manufacture of reducing metal from metal content and movable furnace hearth for manufacturing reducing metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reducing metal of high quality having small content of a gangue or an ash content and little pores by heating to reduce a raw material deposited on a hearth of a movable furnace and simultaneously melting at least once the material in the case of charging the raw material containing metal and a solid reducing agent in the hearth of the furnace, heating it, and manufacturing the reducing metal. SOLUTION: In the case of manufacturing the reducing metal, first a solid reducing agent layer 1 is formed on a hearth 11, and a plurality of recesses 1a are formed on the layer 1. Then, a raw material 2 is charged in the layer 1, heated, metal in the material 2 is reduced by a solid reducing agent, a reduced product 3 containing a gangue is generated, and a slag containing an ash content of the agent as a main body is generated. Then, the raw material is melted, separated into a metal 4 and a slag 5, they are dispersed and fed in the respective recesses 1a. Thereafter, they are cooled, and solidified metal and slag 5 are separated from the hearth 11 by the solid agent, and easily discharged out of the furnace as individual small lumps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing reduced metal from metal-containing material and a movable hearth furnace for producing reduced metal, and more particularly to a method for producing metal containing reduced metal on a hearth moving horizontally in a furnace to be heated. More specifically, the present invention relates to a movable hearth furnace used for continuously producing reduced metal by heating and reducing the metal-containing material while the hearth moves while the hearth moves.

[0002]

2. Description of the Related Art Steel is generally manufactured in a converter or an electric furnace. Among these, the electric furnace method heats and melts scrap and reduced iron using electric energy and, in some cases, further refines it to steel.
However, in recent years, there has been a tendency to use reduced iron instead of scrap due to the tight supply and demand of scrap and the increasing demand for higher quality steel.

[0003] As one of the reduced iron production processes developed to meet such demands, iron ore and a solid reducing agent are charged on a horizontally moving hearth, and the iron ore is transferred from above by radiant heat transfer. A moving hearth furnace method for producing reduced iron by heating and reducing is known (see,
63-108188). The movable hearth furnace used in carrying out this method is, as shown, a furnace capable of heating the charged material in the process of moving the hearth horizontally. It usually takes the form of an annular (swirl) movement as shown in FIG. 1, and this type of movable hearth furnace is usually called a rotary hearth furnace.

Conventionally, as shown in FIG. 1 (a), this rotary hearth furnace is pre-tropical from the supply side of the raw material to the discharge side.
It has an annular furnace body 10 partitioned into 10a, a reduction zone 10b, and a cooling zone 10d, in which an annular hearth 11 is supported so as to rotate. As shown in FIG. 1 (b), a raw material 2 made of a mixture of, for example, iron ore and a solid reducing agent is charged onto the rotating hearth 11. As the raw material, carbonaceous material interior pellets are suitably used. In addition,
The hearth 11 has a refractory applied to the surface, but may be, for example, a granular refractory deposited thereon. A burner 13 is provided on the upper part of the furnace body 10, and a metal-containing oxide such as iron ore deposited on the furnace floor 11 is heated using the burner 13 as a heat source under a reducing agent. To reduce iron. In FIG. 1, reference numeral 14 denotes a charging device for charging the raw material onto the hearth, and reference numeral 15 denotes a discharge device for discharging the reduced product.

[0005] In the operation of the above-mentioned movable hearth furnace, it is preferable that the atmospheric temperature in the furnace body 10 is usually about 1300 ° C. Then, the reduction product after the completion of the reduction treatment is cooled in a cooling zone 10d on the rotating hearth 11 and discharged outside the furnace in order to prevent oxidation outside the furnace and facilitate handling. .

A conventional moving hearth furnace method (Japanese Patent Laid-Open No.
In the operation of No. 108188), the reduction proceeds by a reduction reaction occurring between the iron ore and the solid reducing agent,
The productivity is improved by reducing the thickness of the raw material layer and increasing the moving speed of the hearth.

[0007]

By the way, general metal-containing materials, such as iron ore, contain many gangue components, though depending on the place of production, and on the other hand, coal and coal char as solid reducing agents. However, coke contains a lot of ash. Therefore, if it is attempted to produce reduced iron only by a reduction reaction, it is inevitable that many gangues remain in the product reduced iron, and furthermore, the ash in the reducing agent also adheres to this reduced iron. There was a problem of mixing.

If reduced iron containing a large amount of gangue and ash is charged into an electric furnace, the amount of lime used for adjusting the basicity of slag for dephosphorization and desulfurization increases, resulting in only an increase in cost. However, there has been a problem that the amount of power consumption must be increased due to an increase in the amount of heat required for lime slag formation. Furthermore, the reduced iron obtained only by the reduction reaction usually has many pores, and therefore, when stored in the air, the ratio of reoxidation is high. There was even a risk of a fire from the heat generated during oxidation. In addition, such reduced iron has a small apparent density due to the presence of pores, and floats on slag when used in an electric furnace, so that melting and refining may not be performed smoothly. In addition, if the obtained reduced iron is too large, it takes a long time to dissolve it in an electric furnace, which lowers the productivity of the electric furnace.

Accordingly, in the operation of the conventional movable hearth furnace,
It has been required to use a high-grade iron ore having as little gangue component as possible and to use a reducing agent having a low ash content. However, the fact is that there is a shortage of high-quality iron ore and high-quality coal resources, and in reality, low-grade iron ore must be used.

[0010] From such a background, in the operation of the movable hearth furnace method, it has become necessary to establish a method for effectively separating and recovering the metal component and the gangue component. That is, in order to completely separate the metal component and the gangue component, it is effective to melt and separate the reduced iron, the gangue and the ash during the reduction operation. In other words, it can be seen that in this reduction operation, the molten metal and the molten slag may be generated.

A main object of the present invention is to produce a high-quality reduced metal of a suitable size having a small content of gangue and ash and a small amount of pores. Another object of the present invention is to establish a technology for easily producing low-quality reduced-metals easily at low cost without increasing the refractory unit consumption and electric energy. Still another object of the present invention is to produce a reduced metal which is excellent in storability of a product and convenient for handling.

[0012]

As a method for solving the above-mentioned problems in the prior art, the present invention firstly moves a raw material containing a metal-containing material and a solid reducing agent horizontally in a movable hearth furnace. In order to obtain the reduced metal by heating the raw material while charging the hearth while moving the furnace hearth, the raw material charged and deposited on the hearth is reduced at least once. A method for producing a reduced metal from a metal-containing material, which is characterized by leading to a molten state, is proposed.

[0013] Second, a raw material containing a metal-containing substance and a solid reducing agent is charged on a horizontally moving hearth of a movable hearth furnace, and the raw material is moved while the hearth moves in the furnace. Upon obtaining the reduced metal by heating the raw material, a solid reducing agent layer is formed on the hearth, and the raw material is charged and deposited on the solid reducing agent layer to reduce by heating, and at least once in a molten state A method for producing a reduced metal from a metal-containing material, which is characterized by being led, is proposed.

[0014] Thirdly, a raw material containing a metal-containing substance and a solid reducing agent is charged onto a horizontally moving hearth of a movable hearth furnace, and the raw material is moved while the hearth moves in the furnace. Upon obtaining the reduced metal by heating the raw material, a solid reducing agent layer is formed on the hearth, and the raw material is charged and deposited on the solid reducing agent layer to reduce by heating, and at least once in a molten state The present invention proposes a method for producing reduced metal from a metal-containing material, wherein the method is characterized in that the molten metal particles are cooled while being dispersed on the surface of a solid reducing agent layer.

[0015] Fourth, the present invention is characterized in that a raw material containing a metal-containing substance and a solid reducing agent is charged onto a horizontally moving hearth of a movable hearth furnace, and the raw material is moved while the hearth moves in the furnace. In obtaining the reduced metal by heating the raw material, a solid reducing agent layer is formed on the hearth, and when charging the raw material onto the solid reducing agent layer, a number of irregularities are formed on the surface of the solid reducing agent layer. A metal-containing material, which is deposited so as to be formed, and then reduced by heating, at the same time, is brought into a molten state at least once, and the obtained melt particles are cooled while being dispersed on the surface of the solid reducing agent layer. We propose a method for producing reduced metals from methane.

[0015] Fifthly, the present invention is characterized in that a raw material containing a metal-containing substance and a solid reducing agent is charged onto a horizontally moving hearth of a movable hearth furnace, and while the hearth moves in the furnace, Upon obtaining the reduced metal by heating the raw material, a solid reducing agent layer is formed on the hearth, a large number of recesses are formed on the surface of the solid reducing agent layer, and the raw material is formed on the upper surface of the solid reducing agent layer. And reducing by heating, and introducing the raw material into a molten state at least once on a hearth floor, and cooling the obtained molten particles by keeping the obtained molten particles scattered on the surface of the solid reducing agent layer. A method for producing reduced metals from metal inclusions is proposed.

In the present invention, it is preferable to mix or scatter flux in or on the surface of the solid reducing agent layer covering the hearth. In the present invention, it is preferable to provide an unsoftened molten layer on at least the side of the solid reducing agent layer covering the hearth surface, which is in contact with the hearth. In the present invention,
The layer thickness of the solid reducing agent covering the hearth is preferably 5 mm or more. In the present invention, when the above raw materials are charged and deposited on the solid reducing agent layer, it is preferable that different types of raw materials are stacked to form a deposited layer. In the present invention, it is preferable that all or a part of the powdery recovered material under the sieve obtained by sieving the lump metal and the lump slag among the reduction products is mixed with the above-mentioned raw materials and reused. In the present invention, the raw material preferably contains Zn and / or Pb in the metal-containing material. In the present invention, it is preferable that the atmosphere in the movable hearth furnace has a reducing property at least in a region where the raw material is melted. In the present invention, all or a part of the raw material other than the solid reducing agent is preheated outside the moving hearth furnace, and then mixed with the solid reducing agent and charged into the moving hearth furnace. Is preferred.

Regarding the raw materials used in the present invention, examples of the metal-containing materials include iron ore, Ni or Cr, such as iron ore, Cr ore, Ni ore, iron sand, reduced iron powder, iron making dust, stainless smelting dust, and iron making sludge. Is used. Further, as the solid reducing agent, coal char, coke, steam coal, anthracite, and the like can be used. Each of these metal-containing substances and solid reducing agents may be used alone or in combination of two or more. Such a metal-containing material and a solid reducing agent are mixed to form a charge. The amount of the solid reducing agent in the charge is preferably 50% by weight or less. This is because if the solid reducing agent is mixed at a maximum of about 50% by weight, ordinary reduction of metal-containing substances can be sufficiently achieved. Also, if the solid reducing agent is excessively mixed, the aggregation of the metal or slag is inhibited when the charged raw material is melted, and the generated particles may have a small particle size. If it is desired, the weight ratio of the solid reducing agent in the charge is more preferably 30% by weight or less. In addition, an auxiliary material may be added to this raw material in order to facilitate the melting of the reduced metal and ash during melting. Steelmaking slag, limestone, fluorite, serpentine, dolomite, and the like can be used as auxiliary materials. Further, as this raw material, powder having a size of about 8 mm or less or agglomerated materials such as briquettes and pellets can be used.

On the other hand, the solid reducing agent layer used in the form of being laid on the hearth may use the same reducing agent as that mixed in the raw materials, or may use another kind of solid reducing agent. . The particle size of the solid reducing agent may be adjusted to such a size that the molten material does not penetrate the solid reducing agent layer and reach the hearth refractory. For this purpose the following powders of 8 mm can be used. More preferably, it may be adjusted to about 5 mm or less.

The raw material charged on the hearth or on the solid reducing agent layer formed thereon is heated and reduced and melted to generate metal and slag. At this time, it is preferable to charge the raw materials uniformly on almost the entire surface on the hearth in consideration of the heat transfer efficiency. Then, when the raw material is heated and melted and separated into metal and slag, the metal and slag are agglomerated respectively, and maintain a state in which they are dispersed and dispersed on the surface of the solid reducing agent layer due to their own surface tension. I do. In order to surely realize the scatter of the metal slag, in the present invention, preferably, by forming a concave portion on the surface of the solid reducing agent layer and collecting the concave portion, the scattered metal and the slag are separated and stored. Realize.

The amount of the raw material charged on the hearth is considered as follows. Usually, the volume of the molten metal or slag shrinks to about 10 to 60 vol% with respect to the volume of the raw material. Therefore, the raw material can be charged in an amount up to about 10 times the total volume of the internal space of the concave portion formed on the surface of the solid reducing agent layer. Desirably, the amount of the raw material charged into the furnace is limited to the extent that the molten metal and the slag fill the concave portion if the concave portion is formed on the surface of the solid reducing agent layer.

In the present invention, in carrying out the method for producing reduced metal, it is effective to use a movable hearth furnace having the following structure. That is, the movable hearth furnace is
A horizontally moving hearth, a furnace body covering the hearth, a charging device for charging a metal-containing material, a solid reducing agent and the like onto the hearth, and a charging device on the hearth A mobile hearth furnace having a heating means for heating a charge, a cooling means for cooling a reduction product and slag generated by heating the charge, and a discharge means for discharging the cooled reduction product and slag In the furnace body from the charging device to the discharge device, a pre-tropical zone for preheating the charged material, a reduction zone for reducing the charged material, a melting zone for melting and reducing the charged material, and This is a movable hearth furnace for reducing metal production, which is provided with a cooling zone for cooling a molten reduction product and slag.

In particular, in this movable hearth furnace, it is preferable that both the upper surface of the hearth and the inner surface of the furnace body are formed of refractory material and have a structure that can withstand a high furnace temperature. This furnace is provided with a heating means, for example, by arranging a combustion burner such as fuel gas or liquid fuel above the hearth in the furnace to heat the charge directly by the heat of combustion, or Preferably, the wall is heated to heat the charge with its radiant heat. As an example, a method of heating with an electric heater provided on a hearth or a furnace wall may be used. The above-mentioned pre-tropical zone, reduction zone, melting zone, and cooling zone may be realized by appropriately adjusting the temperature in the furnace without providing a physical partition or the like. By arranging partitions on the furnace body at each boundary with the band,
It is effective to easily maintain the high temperature in the molten zone.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention supplies a raw material containing a metal-containing substance and a solid reducing agent onto a rotating hearth of a movable hearth furnace, and while the hearth rotates in the furnace. By heating and reducing, and further melting at least once,
This is a method for producing a reduced metal, in which a reduced product (reduction product) of a metal-containing substance is generated, and at the same time, a metal component in the reduction product and a slag composed of gangue and ash are separated. Further, the present invention is a method for producing a reduced metal, in which the shape of the generated metal is made to have an appropriate size, thereby facilitating discharge and subsequent handling. Hereinafter, the present invention will be described in more detail.

In the present invention, a raw material containing a metal-containing material and a solid reducing agent is charged on a hearth, the raw material is reduced by heating, and is melted at least once.
The metal in the reduction product can be obtained in a state separated from the slag. Therefore, when this metal is used as a raw material for an electric furnace or the like, since slag is not mixed, the amount of lime for adjusting slag basicity for performing dephosphorization or desulfurization in electric furnace operation can be reduced. Further, in the present invention, the solid reducing agent particles are supplied so as to be spread on the hearth to form a solid reducing agent layer, and the raw material is deposited on the solid reducing agent layer. Even after the solid reducing agent is completely consumed by the reduction reaction, a carbon source can always be supplied from the solid reducing agent layer on the hearth to the metal-containing material in the raw material, particularly to the molten metal. Maintains posture and does not reoxidize reduced products (metals). This means that, even if the oxidizing gas stays in the upper part of the furnace, a reducing atmosphere is always present immediately above the raw material layer and the reduction product layer. In this way, the reduced metal can always be stably produced even if the reduction and melting operations vary. In addition, even when the raw material has segregation and the amount of the solid reducing agent in the raw material is insufficient locally, the solid reducing agent layer immediately below the raw material deposition layer can supplement the carbon content, so that the reduction reaction occurs smoothly. Can be done. Furthermore, the presence of this solid reducing agent layer prevents the molten metal, which is a reduction product, from directly contacting the hearth, and is effective in preventing the erosion of the hearth by the molten metal.

Further, what is important in the present invention is that the reduced product is dispersed in the form of islands (dots) of an appropriate size on the hearth. That is, even after the molten reduction product is re-solidified on the hearth, the coagulated material is maintained in a dispersed state, and the size of each solid is small and the weight is small, so-called outside the furnace. When discharging, make it easy to discharge.
Also, when the solidified material is discharged outside the furnace, an impact is applied to the hearth, but if each solidified material is small and the weight is small, the impact force is reduced, and the chance of damaging the hearth is reduced. Become. The furnace body has at least a discharge port having a size equal to or larger than the size of the solidified metal or slag to discharge the solidified matter to the outside of the furnace, or an opening for providing a discharge device for discharging the solidified matter. If necessary, if the coagulated material is small, these can be made small, and the inside and outside of the furnace can be easily sealed.

In the present invention, it is effective to form a large number of recesses on the surface of the solid reducing agent layer in order to make the above-mentioned reduction products dotted. That is, the raw material charged and deposited on the solid reducing agent layer formed on the hearth is reduced by heating and further melted to form metal and slag, but the metal and slag are agglomerated respectively. The surface of the solid reducing agent layer is moved into each concave portion by the surface tension, is settled as if buried, and is dispersed in an island shape.

In the raw material charged and deposited on the hearth or on the solid reducing agent layer, the volatile components contained in the raw material are transferred to the exhaust gas during the heating-reduction process, and are contained in the metal oxide. The oxygen content is also reduced by the solid reducing agent and moves into the exhaust gas. Therefore, what remains on the hearth is a molten metal component, a gangue component such as SiO ₂ and Al ₂ O _3, and a solid reducing agent.

Next, a preferred embodiment of the reduced iron production process of the present invention will be described with reference to the drawings. First, prior to charging the raw material, a solid reducing agent layer is formed by spraying and depositing a granular solid reducing agent on the rotating hearth. This solid reductant layer formed on the hearth is basically a collection of reductants, but hardly changes except for the loss of volatiles during operation because it does not contain any metal content. Usually, the solid reducing agent contains about 10% of ash, but the remainder is mostly carbonaceous material,
The solid state is maintained even at a high temperature. Therefore, the solid reducing agent layer itself does not adhere to the refractory on the upper surface of the moving hearth. In this sense, the solid reducing agent layer functions as a protective layer for the refractory on the hearth.

On the solid reducing agent layer formed on the hearth, a mixture of a metal-containing material and a solid reducing agent or a mixture of a metal-containing material, a solid reducing agent and an auxiliary material is charged and deposited. Then, while the hearth rotates and moves inside the furnace, it is heated and reduced, and at the same time, the generated reduced product is held until further melting, and the reduced product (metal, slag) generated at this time Shall be in a state of being scattered in an island shape.
This means that reduced metal sized to an appropriate size can be continuously produced.

Now, FIGS. 2 (a), (b), (c) and (d)
It is a figure explaining the example of the raw material laminated structure on the hearth in the said movable hearth furnace, and the process until reduction and melting. As described above, prior to charging the raw materials, the solid reducing agent layer 1 is formed by first spreading the solid reducing agent on the moving hearth 11, and a plurality of solid reducing agent layers are preferably formed on the solid reducing agent layer 1. The recess 1a is formed (FIG. 3). Next, the raw material 2 is charged and deposited on the solid reducing agent layer 1 thus formed. After that, it is heated and reduced using the burner 13 from above the furnace body. As a result, as shown in FIG. 2 (c), the metal-containing material in the raw material 2 is reduced by the action of the solid reducing agent (interior carbonaceous material) mixed together, and the reduction product 3 containing gangue is reduced.
And a slag mainly composed of ash of a solid reducing agent used as a reducing agent contained in the raw material. In addition, the method of compounding the raw materials and the metal-containing materials used,
Although it differs depending on the solid reducing agent, the volume of the gangue-containing reduced product and ash (reduction product 3) is smaller than that of the raw material because the solid reducing agent in the raw material is consumed by the reduction reaction.

Here, the auxiliary material added to the main material is
It is added for facilitating melting when the reduced product or ash is melted, and is preferably steelmaking slag, limestone, fluorite, serpentine, dolomite, or the like. Although these undergo evaporation of crystallization water and some decomposition reactions (for example, CaCO _3, which is the main component of limestone, is thermally decomposed into CaO) before melting, they remain in a solid state I have.

Then, as the heating of the raw material proceeds, the raw material and the auxiliary raw material are not limited to being simply reduced, and further start melting, and as shown in FIG. Melt and separate. At this time, the raw material composed of the metal-containing material and the solid reducing agent, or the raw material obtained by mixing the metal-containing material, the solid reducing agent and the auxiliary raw material is scattered on the solid reducing agent layer 1, so that the metal 4 and the slag are mixed. 5 is formed on the solid reducing agent layer 1. At this time, as shown in FIG. 2 (d), if the concave portion 1a is formed on the surface of the solid reducing agent layer 1, the metal 4 and the slag 5, which are reduction products, cause the surface tension of the molten material and the gravity. By the action, it naturally moves and fits in any of the concave portions 1a of the solid reducing agent layer 1, and the solid reducing agent layer 1 is divided into units of the concave portions 1a. So-called lumps of metal and slag are scattered in islands.

As described above, when the reduction products are dispersed in the concave portions 1a provided in the solid reducing agent layer, the metal and the slag have an appropriate size divided for each concave portion 1a. Moreover, since the volume of the generated metal and slag is only about 10 to 60% of the raw material, the metal and slag are scattered as if buried in the solid reducing agent layer, and they do not contact each other. Since the specific gravity of the metal and the slag is larger than that of the solid reducing agent layer 1, it is expected that they will enter under the solid reducing agent layer 1, but in reality, each metal and slag becomes a small lump, In addition, due to the action of the surface tension, the state of being held on the surface of the solid reducing agent layer is maintained.

The slag and metal generated in such a state on the rotating hearth reach the cooling zone and are cooled.
In short, the solidified metal and slag are separated from the hearth due to the presence of the solid reducing agent layer, and each of them becomes small lumps, so that they can be easily discharged outside the furnace. If the surface of the solid reducing agent layer is flattened without providing recesses, the metal and slag after cooling will not be divided into small pieces, and sometimes large lumps will be formed. A crusher for crushing metal and slag on the hearth may be required. Therefore, it is recommended to form a recess on the surface of the solid reducing agent layer.

This was confirmed by experiments conducted by the inventors on the surface shape of the solid reducing agent layer. That is,
In this experiment, iron ore powder, coke powder, and limestone powder having a particle size of 8 mm or less were mixed at a weight ratio of 7: 3: 1 to prepare a mixed powder as a raw material. Then, based on the raw material lamination conditions 1 as shown in FIG. 4, irregularities are formed on the surface of the solid reducing agent layer 1 formed of coke powder, and the mixed powder 2 is stacked thereon,
This is placed in an experimental device as shown in FIG.
And melted to produce metal and slag. Table 1 shows the experimental results at this time. In addition, FIG.
This shows a heating furnace used in this experiment, and shows a structural example in which a hearth 11 ′ is raised and lowered by a lifting device 16 and set in a furnace body 10 ′. The solid reducing agent layer 1 and the raw material deposition layer 2a formed on this 11 'are heated by the burner 13' and receive the same heat history as described above to reduce,
Is melted. The shape of the concave portion formed in the solid reducing agent layer 1 is a square shape as shown in FIG.
An experiment was also performed on circular combinations having different sizes (raw material lamination conditions 3) as shown in FIG. In Table 1, the shape of the hole means the shape and size of the concave portion formed in the solid reducing agent layer 1. L in the table represents the diameter of a circle (circle equivalent diameter) corresponding to the same area as the shape of the hole. When a variety of shapes are formed as in the raw material lamination condition 3, the maximum value is shown. 4, 6, and 7
(A) is the cross-sectional shape of the concave portion 1a formed on the surface of the solid reducing agent layer 1, and the thickest layer thickness L _{1 of the} raw material powder
And the thinnest layer thickness L ₂ of the raw material powder at the convex portion on the layer surface of the solid reducing agent alone. In addition, as shown in Table 1, the metal after the experiment was obtained by being dispersed in each concave portion.

[0037]

[Table 1]

As a method of forming the above-described solid reducing agent layer on the hearth, a number of recesses are formed on the surface of the solid reducing agent layer in which particles of the solid reducing agent are laid so as to have a constant thickness. The method is fundamental. This forming method can reliably form the concave portion, can easily change the shape, and is effective when the periodicity of the concave portion is required. As a means for forming the concave portion, a means for pressing a roller or stamp having a convex portion on the surface against the surface of the solid reducing agent layer can be appropriately employed.

As another method, first, solid reducing agent particles are laid on the hearth so as to have a constant layer thickness, and a bulk material such as a briquette-shaped material mass is dropped from the upper portion, and the concave portion is formed by the impact. There is a method of forming a depressed deposited layer having a constant thickness by forming another briquette and further charging another metal-containing material and a solid reducing agent between the briquettes. Alternatively, it is also effective to drop the bulk raw material together with other powdery raw materials and charge them.

Still another method is to spread a solid reducing agent in advance in the lower layer and charge and deposit the raw material on the surface of the obtained solid reducing agent layer having a constant thickness. It may be a method of stacking such that unevenness is generated. That is, this method is a method in which the recessed portion 1a is provided in the solid reducing agent layer 1 on the hearth, and the unevenness is controlled by controlling the deposited layer of the charged material. By melting the deposited layer formed by this method in the furnace, the metal generated in the portion where the convex portion is formed, the slag generated around the slag, and the metal gather due to surface tension, so the slag and metal after melting A state in which particles are scattered and held on the surface of the solid reducing agent layer is obtained, and substantially the same operation and effect can be realized. Further, substantially the same function and effect can be realized by charging and depositing a massive raw material in a dispersed state on the surface of the solid reducing agent layer.

The role of the solid reducing agent layer spread on the hearth is to supply a carburizing source to the molten metal and a carbon component to the molten metal,
An object of the present invention is to complement a reduction reaction of a raw material, and to prevent direct contact between a melt and a hearth and prevent erosion of the hearth by the melt. Therefore, the solid reducing agent layer may be mixed with other substances in addition to the carbonaceous material as long as such an effect can be substantially ensured. For example, in the solid reducing agent layer, the flux is uniformly mixed, or mixed so that the concentration becomes non-uniform, or the flux is laminated only on the surface layer of the solid reducing agent layer. You may. The mixed flux is a component that effectively works to reduce S in the molten metal by absorbing S in the solid reducing agent layer.

As the constituent components of the solid reducing agent layer, coal char, coke, steam coal, caking coal, anthracite, and the like can be used. All of these contain carbon and serve as a source of carburization to the molten metal, supply the carbon to the molten metal, and complement the reduction. Some of the solid reducing agents soften and melt when heated, such as caking coal. These may subsequently shrink and crack macroscopically, creating the possibility of the melt on the solid reductant layer penetrating the crack. However, if at least the portion of the solid reducing agent layer laid on the hearth that is in contact with the hearth is formed as an unsoftened molten layer, it is possible to prevent the melt and the hearth from directly contacting each other. Erosion can be reliably prevented. In addition, since the softening and melting behavior of the solid reducing agent changes with the type of the solid reducing agent depending on how the heating pattern is applied,
The layer thickness and the type of carbon material to be laminated are appropriately selected depending on the operating conditions and the solid reducing agent used.

Such a solid reducing agent layer has the above-described effects, but if the amount of the solid reducing agent layer laid on the hearth is small,
In some cases, it cannot function due to consumption by carburization and reduction. Even if not consumed, the vibrations of the furnace may cause the solid reducing agent layer laid down on the hearth to partially disappear. Therefore, in order to prevent the melt from directly contacting the hearth and to more reliably prevent the hearth from being eroded by the melt, in the present invention, the layer thickness of the solid reducing agent laid on the hearth is reduced. It is desirable that the thickness be 5 mm or more, preferably 10 mm or more.

In the present invention, when a raw material containing a metal-containing substance and a solid reducing agent is charged and deposited on a solid reducing agent layer, not only a single type of raw material is stacked to a certain layer thickness, but also different types of raw materials are removed. They may be stacked in multiple stages. For example, on the surface of the solid reducing agent layer, a raw material in which the mixing ratio of the solid reducing agent is reduced is laminated on a metal-containing material that has been considerably reduced, and a raw material composed of a different metal-containing material and a solid reducing agent is further formed thereon. Can be obtained without any problem. According to such a charging method, in the case of a metal-containing material whose reduction has progressed considerably, the reduction proceeds faster than usual, and correspondingly, the molten carburization is faster, and the reduction of the upper layer is performed by using it as a starting point of melting. Will promote melting,
This helps the effects of the present invention. In addition, in charging the raw material, the raw material is intentionally segregated by utilizing the percolation function of the particles, the raw material deposition layer is deposited, for example, a large particle is deposited below, and the raw material of small particles is distributed on the upper. You may charge so that it may be made. Here, in the case of stacking different kinds of raw materials in multiple stages, not only the one in which the mixing ratio of the metal-containing material and the solid reducing agent is changed, but also, for example, blast furnace dry dust collection dust on the upper layer side, lower layer A method of changing the type of the metal-containing material and the solid reducing agent, such as laminating a raw material containing the iron ore and the solid reducing agent on the side, may be used.

The cooled metal and slag may be pulverized in a furnace so that the metal and slag can be easily discharged by a discharge device. At this time, fine powder of metal and slag is generated. Further, even small lumps of metal and slag obtained by cooling while holding the melt particles scattered on the surface of the solid reducing agent are pulverized during the handling process outside the furnace. Further, depending on the method of recovery from the furnace, the solid reducing agent spread on the hearth is discharged together with the furnace. As described above, the simplest way to collect lump metal as a metal raw material and lump slag as a by-product is to sieve outside of the furnace. A mixture of slag and solid reducing agent powder is obtained. Therefore, in the present invention, the powdery metal and powdery slag generated under the sieve, a mixture of the residual solid reducing agent powder, these are collected and added to the charged raw material, and supplied to the furnace again, Completely recycle metal, slag and solid reducing agents. By performing such an operation, it is possible to improve the recovery rate of the metal component and to reduce the unit consumption of the solid reducing agent.
In addition, when charging the under-sieved recovered powder as the raw material on the solid reducing agent layer, it can be applied to the above-described technique of stacking in multiple stages as one of the different raw materials.

As another preferred embodiment of the present invention, it is particularly effective to include a highly volatile metal element such as Zn or Pb in the charge. That is, these Zn and Pb contained in the raw material are very easily vaporized by heating and are transferred into exhaust gas. Therefore, by adding quenching treatment such as water spray to the Zn and Pb vapor-containing exhaust gas, Zn, Pb
It is possible to effectively collect the amount. If iron, Cr, Ni, etc. are contained in the raw materials, these will remain on the hearth, so that the (Zn, Pb) and (Fe, Cr, Ni) components can be naturally separated. Become. Therefore, when such a raw material is used, a high-quality raw material for producing Zn and Pb or a raw material for producing Fe, Cr and Ni can be obtained. Depending on the temperature of the exhaust gas and the oxygen partial pressure, the Zn and Pb may be re-oxidized to a solid state, but this has a very small particle size, and in any case, the particles get on the exhaust gas and go outside the furnace. Is discharged.

In the furnace operation under the method of the present invention, when the raw material charged and deposited on the hearth is melted, if the atmosphere there is reduced, the oxygen partial pressure is reduced, and the solid reducing agent spread on the hearth is reduced. Carburizing from steel to metal can be performed quickly. Further, when the atmosphere adjustment is performed using a gas containing carbon, carburization from the atmosphere gas can also be performed.
This lowers the melting point of the metal and promotes melting,
Productivity is improved. Further, the oxygen partial pressure is reduced, which affects the distribution of sulfur between the slag and the metal, and effectively reduces the sulfur content in the metal.

What is important in the method of the present invention is to make the atmosphere in the furnace reducible. In other words, the same effect can be obtained by supplying a reducing gas so as to cover the raw material layer deposited on the hearth, and in particular, by making at least the melting zone be reducing. When the method of heating by burner combustion is employed, not only the atmosphere in the entire furnace can be made reducible by combustion control of the burner, but also a reducing gas may be introduced into the vicinity of the surface of the raw material layer through another route.

It is effective to preheat the raw materials used in the present invention before charging them into the furnace. In this case, when the mixed raw material is preheated outside the furnace, the coal softens and melts depending on the type of coal and the preheating temperature, and there is a risk of causing handling trouble in the preheating process. In such a case, preheating, which is a source of productivity improvement, is applied to all or a part of the raw material mainly containing metal and solid reducing agent other than the solid reducing agent outside the moving hearth furnace. The raw materials are mixed immediately before being supplied to the movable hearth furnace, agglomerated in some cases, and supplied to the movable hearth furnace, thereby improving productivity while avoiding handling troubles.

In the embodiment of the present invention, the residence time of the raw material in the furnace from the supply of the raw material to the discharge of the raw material is about several tens of minutes, although it varies depending on the method of charging the raw material, the furnace temperature, and the like. During which the raw material is heated, reduced and melted. In this sense, if the heating of the raw material can be accelerated, the productivity of the movable hearth furnace can be improved. That is, the productivity of the movable hearth furnace can be improved by preheating the raw material outside the movable hearth furnace as described above, thereby reducing the residence time in the furnace.

For heating the movable hearth furnace, a method using burner combustion can be employed. Fuel such as natural gas, coke oven gas, heavy oil, air,
An auxiliary agent such as oxygen is supplied, and this fuel or auxiliary agent is preheated by heat exchange with exhaust gas from the furnace, thereby reducing the supply of fuel to the burner, that is, reducing the unit energy used for production. It is possible.

When this burner combustion method is adopted, the temperature of the generated exhaust gas is about 1000 ° C. or higher when preheating the above raw materials.
It is preferable to use this exhaust gas for preheating the raw material outside the furnace. This not only improves the productivity of the movable hearth furnace as described above, but also eliminates the need to supply energy to the movable hearth furnace for preheating the raw materials, thereby reducing the energy consumption unit. It is possible to do.

In the present invention, the raw materials charged in the furnace are melted after reduction. For that, refractories,
The furnace body structure must be able to withstand the high temperatures. This is accompanied by increased equipment costs. The reduction of the raw material is faster as the temperature is higher, but a practical reduction rate can be ensured even if the temperature is not high enough to melt. On the other hand, if the zone for melting is shorter than necessary, the moving speed of the horizontally moving hearth of the movable hearth furnace is reduced to secure the residence time necessary for melting, and the residence time in the furnace results. Lengthens, and lowers productivity. That is, the length of the zone in which the melting is performed is appropriately selected in terms of both maintaining the productivity and suppressing the equipment cost.

The metal and slag products melted on the hearth are solidified before being discharged out of the furnace. At this time, natural gas supplied to the burner, coke oven gas, fuel such as heavy oil, and a combustion aid such as air and oxygen also play a role as a cooling medium, preheat the fuel and combustion aid, and produce energy per unit of production. Can be reduced. Also, using nitrogen, reducing gas, etc. to cool the metal and slag products melted on the hearth, thereby controlling the atmosphere of the furnace when melting preheated nitrogen, reducing gas, etc. It can also be used. When the metal and slag are discharged outside the furnace, not only the metal and slag but also all or part of the solid reducing agent layer is discharged depending on the discharge device and method. It is also possible to substantially discharge only metal and slag. When the movable hearth furnace is a rotary furnace and the solid reducing agent is partially discharged or substantially not discharged, the solid reducing agent moves to the raw material supply unit while remaining on the hearth. At this time, the raw material supply unit supplies the solid reducing agent only for the consumed amount.

[0055]

EXAMPLE 1 In this example, a rotary hearth on which an alumina-based refractory was applied was provided on the upper surface of a movable hearth having a diameter of 2.2 m, and a burner was disposed above the hearth. The following operation was performed using a rotary hearth furnace shown in FIG. 8 in which these were covered with an annular furnace body. As shown in FIG. 8, the rotary hearth is
a, a reduction zone 10b, a melting zone 10c, and a cooling zone 10d. A raw material mainly composed of an iron-containing substance and a solid reducing agent is charged and deposited on the rotary hearth to form a raw material layer 2. In this equipment, the same reference numerals as those shown in FIG. 1 indicate the same configuration. Also, reference numeral 17
Is a cooler arranged in front of the discharge port for cooling and removing reduced iron. FIG. 9 shows a schematic diagram of the vicinity of the discharge port used for this operation. After the metal was discharged by the discharge device 15, the metal and the slag were separated by a magnet. In some cases, a crusher 18 was used. Further, in this embodiment, the method of charging and depositing the raw material at the supply port of the furnace is such that the raw material such as the metal-containing material and the solid reducing agent is shown by the charging device 14 in FIGS. 10, 11, 12, and 13. Each of the four types of raw materials was deposited on the rotary hearth 11 under the conditions shown in the examples.
In this example, the concave portion formed on the surface of the solid reducing agent layer was formed by pressing a roller having a convex portion on the surface after forming the solid reducing agent layer. As the metal-containing material, iron ore having a gangue content (SiO ₂ , Al ₂ O _3, etc.) of 7% or more and having the composition shown in Table 2 is used, and the solid reducing agent contains ash content of 6 to 11%. The components having the composition shown in Table 3 were used, and the sieves thereof were adjusted to 3 mm or less. Table 4 shows the operation results of the above examples. No. 1 showing conforming examples
6 to 6 are examples of the deposition shape of FIG. Under any of the conditions, there was no damage to the refractory of the hearth, no trouble in product discharge, and a high iron recovery rate of 97.4% or more.
The ash could be recovered with almost no ash removed, and there was no significant decrease in productivity. For No. 5, 2
There was a portion where the metal and slag in each of the three concave portions were combined into a large lump, but there was no particular problem in discharging. Compatible Examples Nos. 7 and 8 are examples of the deposition shape shown in FIG. 11, but they are layered in small compartments and scattered so that the raw material does not directly contact the hearth via the solid reducing agent layer. It is. Under these lamination conditions, even if the reduced iron and ash are melted for the gangue and ash removal operation, the hearth refractory is separated by the slag and molten iron because the solid reductant layer separates it from the hearth refractory. There was no damage. But,
Since the solid reducing agent layer is exposed on the surface from the time of deposition, the use of radiant heat to this part is slightly inferior.
6 was slightly lower in productivity. Applicable example No. 9, 10
Is an example in which the solid reducing agent layer surface is deposited smoothly and the raw material mixed powder is deposited in a layered manner on the entire surface thereof under the lamination conditions of FIG. In this example, when reducing iron and ash were melted to remove gangue and ash, slag and metal both became large plates, and although there were partial cracks due to shrinkage in the cooling process, The metal and slag after cooling are in a large plate shape.
Some were connected up to around 17. Therefore, in these adaptation examples, a crusher is provided before the discharge device, and the product is crushed on the hearth before discharging the product outside the furnace.
Although there was an increase in equipment costs and running costs for the installation of the crusher, this measure enabled operation in these conforming cases and produced metal. No. 11 of conforming example
13 shows an example in which the raw material 2 is layered on the hearth refractory without the layer of the solid reducing agent under the lamination condition of FIG. In such a raw material sedimentary layer, reduced iron and ash were melted for the operation of removing gangue and ash, but since the raw material was directly loaded on the hearth refractory, the hearth refractory was melted. Suffered erosion. Also, both the slag and the metal become like a large plate, and although there are partial cracks due to shrinkage during the cooling process, the metal and the slag after cooling have a large plate shape, and the cooling shown in FIG. Some were connected to the vicinity of vessel 17. Therefore, a crusher was provided before the discharge device, and the product was crushed on the hearth before discharging the product outside the furnace. These measures have made it possible to operate equipment despite the increase in equipment costs for the installation of the crusher, running costs such as electric power for operating the crusher, and slight erosion of the hearth refractory. , The production of metal. In addition,
In this example, the solid reducing agent layer 1 in the portion in contact with the hearth did not soften and melt in the vicinity of the discharge part in any of Nos. 1 to 10.

[0056]

[Table 2]

[Table 3]

[Table 4]

Example 2 The following operation was carried out using the same apparatus as in Example 1.
Raw materials were loaded at the supply port of the furnace by the loading device 14 under the laminating conditions shown in FIG. However, limestone is contained in the solid reducing agent layer 1 in a weight ratio of 5%.
% Was added. As shown in Table 5, when the operating conditions were almost the same, it was found that S in the recovered metal was lower when the limestone was distributed to the solid reducing agent layer.

[0058]

[Table 5]

Example 3 The following operation was performed using the same apparatus as in Example 1.
The loading of the raw material at the supply port of the furnace was performed by the charging device 14 under the raw material stacking conditions shown in FIG. In the figure, the raw material (lower layer) 21 and the raw material (upper layer) 22 have different compositions as shown in Table 6. In the adaptation example 16, not only the iron-containing material shown in Table 2 but also the powdered pig iron shown in Table 7 was added to the raw material (lower layer) 21 as a metal-containing material. As shown in Table 6, when the iron loading per unit area is the same and the operating conditions other than the furnace rotation speed are almost the same, the conditions in which the raw material (lower layer) 21 is mixed with powdered pig iron It was possible to produce even if the rotation speed was increased, that is, it was possible to increase the production speed. Compliance Example 17
(Upper layer) Blast furnace dry dust collection dust and raw materials shown in Table 9 in 22 (lower layer)
As 21, the same one as in Fitting Example 16 was used. Because the properties of the raw material in the upper layer are different, direct comparison of productivity is not possible, but production was possible without any problems.

[0060]

[Table 6]

[Table 7]

Example 4 The following operation was carried out using the same apparatus as in Example 1.
Raw materials at the supply port of the furnace were loaded and deposited on the hearth 11 by the loading device 14 under the lamination conditions shown in FIG. After the lump formed on the solid reducing agent layer 1 was discharged by the discharge device 15, the whole amount was sieved through a 3 mm sieve. Then, the entire under-sieve was mixed with the raw material and recycled. The recycled content in the raw material was 1.5 to 2% of the raw material. As shown in Table 8, when the operating conditions were almost the same, the metal recovery rate could be increased.

[0062]

[Table 8]

Example 5 The following operation was carried out using the same apparatus as in Example 1.
However, the exhaust gas from the furnace was sprayed with water to cool the exhaust gas, and dust in the exhaust gas was trapped and collected in water. The raw materials were stacked on the hearth 11 by the charging device 14 under the lamination conditions shown in FIG. However, the raw material is blast furnace dry dust collection dust.
Those containing n and Pb were used. The dry dust contains a part of coke charged into the blast furnace. The composition is shown in Table 9. As a result, as shown in Table 10, ZnO and metal were contained in the secondary dust trapped in water.
Pb was recovered. Here, the secondary dust contains almost no Fe component. In addition, it melts and solidifies in the furnace,
Most of the recovered metal was Fe, and there was no Zn or Pb.

[0064]

[Table 9]

[Table 10]

Example 6 Using the same apparatus as in Example 1, the following operation was carried out.
However, temperature compensation in the melting zone was performed by pure oxygen propane burner combustion, and the degree of oxidation of the exhaust gas after combustion was adjusted by controlling the air ratio. The raw material is charged by the charging device 14 in FIG.
Under the lamination conditions shown in FIG. Table 11 shows the operation results. When the operating conditions other than the degree of oxidation of the post-combustion gas, that is, the reducing property of the atmosphere, and the operating speed other than the rotation speed of the furnace were almost the same, the productivity could be slightly increased by increasing the reducing property of the atmosphere.

[0066]

[Table 11]

Example 7 Using the same apparatus as in Example 1, the following operation was carried out.
However, as shown in FIG. 15, a rotary kiln-type preheating device having an inner diameter of 1 m and a length of 3 m was used, and ore and exhaust gas from a movable hearth furnace were introduced into the device, and the ore was preheated by the exhaust gas. The exhaust gas varied from 1000 ° C to 1100 ° C, and the preheated ore was heated to around 500 ° C. The preheated ore is introduced into a mixer (1 m in diameter, 3 m in length) and mixed with a solid reducing agent at room temperature (coal in Table 12). Then, the charging device 14 shown in FIG. It was stacked on the hearth 11 of the movable hearth furnace under the conditions. Table 13 shows the operation results at this time. In operations that do not preheat ore, the energy input to burner fuel, consumed solid reductant, etc. is 7.0
Gcal / t-metal, but when using preheated ore
Reduced to 6.8 Gcal / t-metal.

[0068]

[Table 12]

[Table 13]

[0069]

As described above, according to the present invention, while using simple equipment, reduced iron containing no gangue or ash can be produced from a metal-containing substance and a solid reducing agent by using an electric furnace or the like. A highly evaluated reduced metal can be obtained as a raw material for refining. Further, by forming the solid reducing agent layer on the hearth, damage to the equipment can be avoided. Furthermore, by generating the reduced metal by scattered on the solid reducing agent layer on the hearth, the handling of the reduced metal becomes extremely easy, and a reduced metal suitable as a raw material for an electric furnace can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a movable hearth furnace.

FIG. 2 is an explanatory diagram of a state in which raw materials are stacked on a hearth and a change when a reduction product is melted, which conforms to the present invention.

FIG. 3 is an explanatory view of a method of stacking raw materials on a moving hearth suitable for the present invention so as to be scattered so as not to directly contact the hearth via a solid reducing agent layer.

FIG. 4 is an explanatory diagram of lamination condition 1 used in an experiment.

FIG. 5 is an explanatory view of a heating furnace used in the experiment.

FIG. 6 is an explanatory diagram of lamination condition 2 used in an experiment.

FIG. 7 is an explanatory diagram of lamination condition 3 used in an experiment.

FIG. 8 is an explanatory diagram of a movable hearth furnace used in an example.

FIG. 9 is an explanatory diagram of a discharge device used in the embodiment.

FIG. 10 is an explanatory diagram of lamination conditions A of raw materials used in Examples.

FIG. 11 is an explanatory diagram of lamination conditions B of raw materials used in Examples.

FIG. 12 is an explanatory diagram of lamination conditions C of raw materials employed in Examples.

FIG. 13 is an explanatory diagram of lamination conditions D of raw materials used in Examples.

FIG. 14 is an explanatory diagram of lamination conditions of raw materials employed in Example 3.

FIG. 15 is a raw material preheating apparatus employed in Example 7.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solid reducing agent layer 1a recess 2 raw material 2a mixed powder 3 reduction product 4 metal 5 slag 10, 10 'furnace body 10a pre-tropical 10b reduction zone 10c melting zone 10d cooling zone 11, 11' hearth 13, 13 'burner 14 Loading device 15 Discharge device 16 Elevating device 17 Cooler 18 Crusher 21 Raw material (lower layer) 22 Raw material (upper layer)

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Mikiharu Takeda 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Inside the Technical Research Institute of Kawasaki Steel (72) Inventor Hiroshi Itaya 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki 4K001 AA10 BA02 GA07 GA11 GB01 GB02 HA01 4K012 DD01 DD02 DD03 DD08 DD09 4K050 AA00 BA02 CA09 CD02 CD30 CF01 CF11 CG22

Claims (14)

[Claims] 1. A raw material containing a metal-containing material and a solid reducing agent is loaded on a horizontally moving hearth of a movable hearth furnace, and the raw material is heated while the hearth moves in the furnace. A method for producing a reduced metal from a metal-containing material, wherein the reduced metal is heated and reduced at the same time as the raw material charged and deposited on the hearth to obtain a reduced metal. 2. A raw material containing a metal-containing material and a solid reducing agent is loaded on a horizontally moving hearth of a movable hearth furnace, and the raw material is heated while the hearth moves in the furnace. Upon obtaining the reduced metal by forming a solid reducing agent layer on the hearth, charging and depositing the raw material on the solid reducing agent layer, reducing by heating, and leading to a molten state at least once. For producing reduced metals from metal containing materials. 3. Loading a raw material containing a metal-containing material and a solid reducing agent onto a horizontally moving hearth of a movable hearth furnace, and heating the raw material while the hearth moves in the furnace. Upon obtaining a reduced metal by forming a solid reducing agent layer on the hearth, charging and depositing the raw material on the solid reducing agent layer and reducing by heating, at least once leading to a molten state, and obtained A method for producing reduced metal from a metal-containing material, wherein the molten particles are cooled while being dispersed on the surface of the solid reducing agent layer. 4. A raw material containing a metal-containing material and a solid reducing agent is loaded on a horizontally moving hearth of a movable hearth furnace, and the raw material is heated while the hearth moves in the furnace. In order to obtain reduced metal, a solid reducing agent layer is formed on the hearth, and when charging the raw material onto the solid reducing agent layer, the solid reducing agent layer is deposited so as to generate a number of irregularities on the surface of the solid reducing agent layer. At the same time as heating and reducing, at least once, to a molten state, and cooling the reduced metal from the metal-containing material, characterized in that the obtained molten particles are cooled by being kept dotted on the surface of the solid reducing agent layer. Production method. 5. A method of charging a raw material containing a metal-containing material and a solid reducing agent onto a horizontally moving hearth of a movable hearth furnace, and heating the raw material while the hearth moves in the furnace. In obtaining a reduced metal by forming a solid reducing agent layer on the hearth, forming a large number of recesses on the surface of the solid reducing agent layer, charging and depositing the raw material on the upper surface of the solid reducing agent layer A method for producing a reduced metal from a metal-containing material, wherein the reduced particle is cooled at least once by heating and reducing to at least one time, and the obtained molten particles are cooled while being dispersed on the surface of the solid reducing agent layer. 6. The method according to claim 2, wherein a flux is mixed or scattered in or on the surface of the solid reducing agent layer covering the hearth. 7. The method according to claim 2, wherein an unsoftened molten layer is provided on at least a side of the solid reducing agent layer covering the hearth surface, which is in contact with the hearth. 8. The method according to claim 2, wherein the layer thickness of the solid reducing agent covering the hearth is 5 mm or more. 9. The method according to claim 2, wherein when the raw materials are charged and deposited on the solid reducing agent layer, different kinds of raw materials are stacked to form a deposited layer. Production method. 10. The method according to claim 1, wherein all or a part of the powdery recovered material obtained by sieving the lump metal and lump slag among the reduction products is mixed with the raw material and reused. The method according to claim 1. 11. The method according to claim 1, wherein the raw material contains Zn and / or Pb in the metal-containing material. 12. The production method according to claim 1, wherein the atmosphere in the movable hearth furnace has a reducing property at least in a region where the raw material is melted. 13. The whole or a part of the raw material other than the solid reducing agent is preheated outside the moving hearth furnace, and then mixed with the solid reducing agent and charged into the moving hearth furnace. The manufacturing method according to claim 1, wherein: 14. A hearth that moves horizontally, a furnace body covering the hearth, and a charging device for charging a charge containing a metal-containing substance and a solid reducing agent onto the hearth. And heating means for heating the charge on the hearth, cooling means for cooling the reduction product and slag generated by heating the charge, and discharge means for discharging the cooled reduction product and slag. In a movable hearth furnace, a pre-tropical zone for preheating the charged material, a reduction zone for reducing the charged material, and a melting and reducing the charged material are provided in a furnace heading from the charging device to the discharging device. A moving hearth furnace for producing reduced metal, comprising: a melting zone; and a cooling zone for cooling the molten reduction product and slag.