Flash smelting furnace, method for operating flash smelting furnace, and metal smelting method

Abstract

The present invention reduces risk when there is an increase in the charging ratio of a recycled raw material mainly composed of metal. This flash smelting furnace is for separating a high-temperature melt produced by reacting a raw material with oxygen in a reaction shaft 2 into a matte layer 3a containing matte, which is a sulfide of a prescribed metal, and a slag layer 3b existing above said matte layer on a furnace bed of a settler 3. The flash smelting furnace comprises: a prescribed slope area S2 provided on the furnace bed S to guide a molten metal, which is the molten product of the prescribed metal that has remained at the bottom of the matte layer without undergoing sulfurization, to the side of a furnace wall 3W of the settler; and metal tap holes Hc, Hc formed in the furnace wall to extract the molten metal stored at the bottom of the slope area out of the furnace.

Description

Autogenous Furnace, Operating Method of Autogenous Furnace, and Metal Smelting Method

[0001] The present invention relates to an autogenous furnace used for metal smelting such as copper, an operating method of the autogenous furnace, and a metal smelting method.

[0002] For example, as shown in FIG. 7 of Patent Document 1, an autogenous furnace in metal smelting such as copper includes a reaction shaft (2), a settler (3), and an uptake (4), and a concentrate burner 7 is provided at the top of the reaction shaft (2). The raw material containing concentrate is blown into the furnace by the concentrate burner 7 together with oxygen-enriched air or hot high-temperature air to instantaneously cause a chemical reaction, and is separated on the hearth of the settler 3 into a matte layer (6) containing matte, which is a sulfide of copper, and a slag layer (5) above the matte layer (6) (the numbers in parentheses are the reference numerals in Patent Document 1. The same applies hereinafter).

[0003] The matte in the matte layer (6) is withdrawn from a matte tap hole provided in the furnace wall arranged along the longitudinal direction of the settler (3), and the slag in the slag layer (5) is withdrawn from a slag tap hole provided in the furnace wall arranged on the uptake (4) side along the short-side direction of the settler (3). The slag withdrawn from the slag tap hole is smelted in a reverberatory furnace, and the copper mixed in the slag is recovered. The recovered copper is processed in a converter together with the matte withdrawn from the matte tap hole, and then becomes higher-grade electrolytic copper by electrolytic refining.

[0004] JP-A-2011-075183 JP-A-2012-057905 JP-A-2017-155260 JP-A-2017-155260

[0005] In recent years, the proportion of recycled materials, primarily composed of copper metal, has been increasing in the raw materials, leading to a tendency for the proportion of copper metal that does not sulfurize in the furnace to rise. If this copper metal accumulates in the round-bottomed hearth of the self-smelting furnace and is left to stagnate for a long period, the impurity elements contained in the copper metal will concentrate, resulting in a low melting point state. This increases the risk of the copper metal penetrating into the joints of the furnace bottom bricks or impregnating the furnace bottom bricks themselves, leading to a loss of the furnace bottom brick's insulating function and an increased risk of molten metal leaking from the furnace bottom. Furthermore, if the surface level of the accumulated copper metal reaches the level of the mat tap holes, and the copper metal mixes with the mat extracted from these mat tap holes, there is an increased risk of, for example, the melting and damage of copper mat troughs. There is also an increased risk of unintentionally supplying highly impurity metal to the converter and the melting and damage of the copper water-cooling jacket that makes up the furnace wall of the self-smelting furnace. To mitigate these risks, conventional self-smelting furnaces can only process copper-metal-based recycled materials within a range where copper metal is not generated or where the amount generated is negligible. This has resulted in the problem that the processing efficiency of such recycled materials cannot be increased beyond a certain point.

[0006] Therefore, in view of the above problems, the present invention aims to provide a self-smelting furnace, a method for operating a self-smelting furnace, and a metal smelting method that have a configuration capable of reducing the risks when the input ratio of metal-based recycled raw materials increases.

[0007] A self-smelting furnace according to the present invention separates a high-temperature molten material produced by reacting raw materials with oxygen in a reaction shaft into a mat layer containing a mat, which is a sulfide of a predetermined metal, and a slag layer present on the mat layer on the hearth of a settler, and is characterized by comprising: a predetermined slope area provided on the hearth to guide the molten metal, which is the molten material of the predetermined metal that remains at the bottom of the mat layer without sulfidation, toward the side of the furnace wall of the settler; and a metal tap hole formed in the furnace wall to extract the molten metal stored at the bottom of the slope area to the outside of the furnace.

[0008] In any self-melting furnace according to the present invention, the range in which the slope area is formed may be a predetermined range below the reaction shaft.

[0009] In any self-smelting furnace according to the present invention, the hearth of the setter is the upper end surface of a brick array with a round bottom shape and an inverted arch cross-section, and the cross-sectional shape of the slope area of ​​the hearth may be an inverted arch tilted such that the height position of the settling support on the metal tap hole side is lower than the height position of the settling support on the opposite side of the metal tap hole.

[0010] In any self-smelting furnace according to the present invention, the cross-sectional shape of the non-slope area of ​​the hearth may be an inverted arch shape in which the height position of one smelting support portion and the height position of the other smelting support portion are the same.

[0011] In any self-smelting furnace according to the present invention, the height position of the bottom of the slope area of ​​the hearth may be lower than the height position of the bottom of the non-sloping area of ​​the hearth.

[0012] In any self-smelting furnace according to the present invention, the height position of the mat tap hole in the furnace wall may be set to the height position of the serration receiving portion in the non-slope area, and the height position of the metal tap hole in the furnace wall may be set to the height position of the serration receiving portion on the metal tap hole side of the slope area.

[0013] In any self-smelting furnace according to the present invention, the horizontal position of the metal tap hole in the furnace wall may be adjusted so as not to be the same as the horizontal position of the mat tap hole in the furnace wall.

[0014] In any self-smelting furnace according to the present invention, a gas cooling mechanism may be further provided for cooling the bottom of the settler in areas of the bottom of the furnace.

[0015] In any self-smelting furnace according to the present invention, a means for measuring the amount of heat removed by the gas cooling mechanism may be further provided for each area of ​​the furnace bottom.

[0016] A self-smelting furnace according to the present invention may further include a temperature measuring means for measuring the temperature of the furnace bottom of the setter for each area of ​​the furnace bottom.

[0017] The method for operating a self-melting furnace according to the present invention is a method for operating a self-melting furnace according to any of the present invention, characterized in that when the surface level of the molten metal reaches the level of the mat tap hole, or when this is predicted, the operation of removing the molten metal from the metal tap hole in the furnace wall is initiated.

[0018] In any method of operating a self-melting furnace according to the present invention, whether or not the surface level of the molten metal has reached the level of the mat tap hole may be determined by whether or not the molten metal has begun to be mixed into the mat that is pulled out from the mat tap hole of the furnace wall.

[0019] In any method of operating a self-melting furnace according to the present invention, whether or not the surface level of the molten metal has reached the level of the mat tap hole may be determined by whether or not the area to which the molten metal adheres to the measuring rod inserted through the measuring hole of the setter has reached the level corresponding to the mat tap hole level.

[0020] In any self-melting furnace operation method according to the present invention, the operation of extracting the molten metal from the metal tap hole may be stopped when the surface level of the molten metal falls to a second level lower than the mat tap hole level, or when this is predicted.

[0021] In any method of operating a self-melting furnace according to the present invention, whether or not the surface level of the molten metal has decreased to the second level can be determined by whether or not the area to which the molten metal adheres to the measuring rod inserted through the measuring hole of the setter has decreased to the level corresponding to the second level.

[0022] In any self-melting furnace operation method according to the present invention, when the operation of removing the molten metal from the metal tap hole is started, the operation of removing the mat from the mat tap hole in the furnace wall may be stopped, and when the operation of removing the mat from the mat tap hole in the furnace wall is started, the operation of removing the molten metal from the metal tap hole may be stopped.

[0023] In any method of operating a self-melting furnace according to the present invention, the operation of removing all molten metal, including the molten metal, the mat, and the slag, from the metal tap hole may be performed as needed.

[0024] In any of the self-melting furnace operating methods according to the present invention, if there is an area where the heat load estimated from the amount of heat removed or the temperature exceeds a predetermined range, the flow rate of the cooling gas to that area may be increased.

[0025] In any method of operating a self-melting furnace according to the present invention, if there is an area where the heat load estimated from the amount of heat removed or the temperature falls below the predetermined range, the flow rate of the cooling gas to that area may be reduced.

[0026] A metal smelting method according to the present invention is a metal smelting method using any of the self-smelting furnaces according to the present invention, characterized in that molten metal extracted from the metal tap hole of the self-smelting furnace is supplied to a first downstream furnace together with the self-smelting furnace mat extracted from the mat tap hole of the self-smelting furnace.

[0027] In any metal smelting method according to the present invention, the self-smelting furnace slag extracted from the slag tap hole of the self-smelting furnace may be supplied to a second downstream furnace to separate it into a second mat containing the metal and a second slag present on the second mat, and the second mat may be supplied to the first downstream furnace.

[0028] In any metal smelting method according to the present invention, at least one of the following steps may be performed during the operation of the second downstream furnace: reduction of the second slag, heating of the second slag, supply of additives for modifying the second slag, oxidation of the second slag, oxidation of the second matte, heating of the second matte, or oxidation of the molten metal.

[0029] In any metal smelting method according to the present invention, molten metal may be mixed into the self-smelting furnace mat, and the self-smelting furnace mat mixed with the molten metal may be supplied to the first downstream furnace.

[0030] In any metal smelting method according to the present invention, the mixing of molten metal into the self-smelting furnace slag is permitted, the self-smelting furnace slag mixed with the molten metal is supplied to the second downstream furnace, the molten metal is allowed to settle on the hearth of the second downstream furnace, and the settled molten metal is supplied to the first downstream furnace together with the second mat.

[0031] In any metal smelting method according to the present invention, the raw materials include recycled materials, and the weight ratio of particulate materials and granular materials in the recycled materials may be adjusted in order to adjust the balance between the amount of molten metal extracted from the second downstream furnace and the amount of molten metal extracted from the self-smelting furnace.

[0032] In any metal smelting method according to the present invention, the pretreatment conditions of the recycled raw materials may be adjusted to adjust the weight ratio.

[0033] The self-smelting furnace according to the present invention includes a slope area that guides molten metal accumulated at the bottom of the mat layer without sulfidation toward the furnace wall of the setter, and a metal tap hole at the bottom of the slope area that allows the molten metal stored therein to be removed from the furnace. This allows the molten metal to be removed in a timely and smooth manner. Therefore, the following risks can be reduced or avoided: (1) the risk of molten metal accumulated in the center of the hearth of the self-smelting furnace leaking from the bottom of the furnace; (2) the risk of molten metal reaching the mat tap hole level damaging the copper mat trough; (3) the risk of high-impurity metal being unintentionally supplied to the converter; and (4) the risk of damaging the copper water-cooling jacket that constitutes the furnace wall of the self-smelting furnace. Accordingly, the self-smelting furnace and its operating method according to the present invention have the effect of reducing the risks when the input ratio of metal-based recycled materials increases. The metal smelting method using the self-smelting furnace according to the present invention has the effect of safely processing recycled materials because it uses the self-smelting furnace according to the present invention.

[0034] This is a schematic front cross-sectional view of a self-smelting furnace according to an embodiment. This is a schematic perspective view of the shape of the hearth of the setter. This is a schematic cross-sectional view of the inside of the front furnace wall of the setter. This is a cross-sectional view taken along the line X-X in Figure 1. This is a cross-sectional view taken along the line Y-Y in Figure 1. This is an explanatory diagram illustrating the configuration of the air cooling mechanism located below the bottom of the furnace. This is an explanatory diagram illustrating the layout of the temperature measuring means in the cross-sectional view taken along the line X-X in Figure 1. This is an explanatory diagram illustrating the layout of the temperature measuring means in the cross-sectional view taken along the line Y-Y in Figure 1. This is a schematic diagram illustrating the flow of a conventional copper smelting method. This is a schematic diagram illustrating the flow of an embodiment of the copper smelting method. This is a schematic diagram illustrating the flow of a second embodiment of the copper smelting method.

[0035] 1. Embodiments The embodiments of the self-smelting furnace and its operating method according to the present invention will be described below. Here, copper is particularly assumed as the predetermined metal, and the self-smelting furnace and its operating method used in copper smelting will be given as an example, but the present invention is also applicable to self-smelting furnaces and their operating methods used in the smelting of metals other than copper.

[0036] 1-1. Configuration of the Self-Smelting Furnace The configuration of the self-smelting furnace will be described below. Figure 1 is a schematic front cross-sectional view of the self-smelting furnace according to this embodiment. Note that in Figure 1, the uneven shape of the hearth S is exaggerated more than it actually is. As shown in Figure 1, the self-smelting furnace 1 according to this embodiment comprises a settler 3 which is roughly rectangular in plan view, a roughly cylindrical reaction shaft 2 which is projected from the ceiling near one end of the settler 3, and an uptake 4 which is projected from the ceiling near the other end of the settler 3. The entire furnace body of the self-smelting furnace 1 is made of a shell (boiler body) made of a metal material such as steel. A concentrate burner 7 is located at the top of the reaction shaft 2, and an oxygen-enriched air supply unit 8 is provided in the concentrate burner 7. When oxygen-enriched air or high-temperature hot air is blown into the reaction shaft 2 via the supply unit 8, a chemical reaction occurs instantaneously. Due to the difference in specific gravity, the reacted raw materials are separated on the surface of the hearth 1a of the settler 3 (hereinafter referred to as "hearth S") into a matt layer 3a containing matt, which is copper sulfide, and a slag layer 3b located above the matt layer 3a. The copper content (by weight) of the matt layer 3a is, for example, 65%, and the slag layer 3b contains iron oxide, silica, etc. The exhaust gas from the top of the slag layer 3b is then guided to a waste heat boiler (not shown) via an uptake 4, and the exhaust gas cooled in the waste heat boiler is sent to the sulfuric acid plant.

[0037] 1-2. Hearth Shape The following describes the general shape of the hearth S of the settler 3. Figure 2 is a schematic perspective view of the hearth shape of the settler. Note that the grid lines in Figure 2 are drawn to make the shape of the hearth S easier to understand and do not necessarily indicate the boundaries of the hearth bricks. Also, although the front hearth wall 3W, side hearth wall 3W', and rear hearth wall 3W'' in Figure 2 are all drawn as vertical surfaces, they are actually inclined surfaces. As shown in Figure 2, the hearth bottom 1a of the settler 3 is composed of hearth brick arrays with an inverted arch cross-section assembled in a round bottom shape, and the upper end surface of these hearth brick arrays is used as the hearth S. Of this hearth S, the predetermined range below the reaction shaft 2 in which mat particles and slag particles are suspended is a predetermined slope area S2. Here, the "predetermined range" refers to a predetermined length range that can be created by dividing the hearth S in the longitudinal direction as shown in Figure 2, and in particular refers to a rectangular area in plan view that encompasses the projected area of ​​the reaction shaft 2. Alternatively, the "predetermined range" refers to a rectangular area in plan view that is created by extending the rectangular area encompassing the projection region of the reaction shaft 2 in the direction of the side furnace wall 3W'. A smooth slope is provided in the slope area S2 of this predetermined range. Therefore, the molten metal, which is the molten material of a predetermined metal (copper in this case) supplied from the concentrate burner 7 and which has settled and accumulated at the bottom of the matte layer 3a (Figure 1) without sulfidation, is guided by the slope of the slope area S2 and accumulates on the side of the front furnace wall 3W (hereinafter referred to as "front furnace wall 3W") which is arranged along the longitudinal direction of the settler 3. The low melting point state of the molten metal that causes the aforementioned risks is due to the concentration of impurity elements that have migrated from the matte to the molten metal over time. In this specification, "molten metal" may contain not only the elements of the predetermined metal (copper in this case) but also impurity elements such as iron, tin, and lead. The lowest part of the slope area S2, the bottom S2-b, is the part that is in contact with the front furnace wall 3W. The height of this bottom S2-b is lower than the height of the bottom S1-b of the non-slope area S1, and corresponds to the metal tap hole level Lc. The metal tap hole level Lc is the height of the metal tap hole Hc, which will be described later.The highest point of the non-slope area S1, the top S1-u, is the portion of the non-slope area S1 that is in contact with the front furnace wall 3W and the furnace wall opposite the front furnace wall 3W (hereinafter referred to as the "rear furnace wall 3W"). The height of this top S1-u corresponds to the mat tap hole level La. The mat tap hole level La is the height of the mat tap hole Ha, which will be described later. Since the boundary between the slope area S2 and the non-slope area S1 is smoothly continuous, the hearth S as a whole has a smooth curved surface.

[0038] 1-3. Configuration of the Tap Holes Figure 3 is a schematic cross-sectional view of the inside of the front furnace wall of the settler. As shown in Figure 3 and Figure 2 above, the self-smelting furnace 1 of this embodiment is provided with a plurality of (in this case, six) mat tap holes Ha, Ha, Ha, Ha, Ha, Ha for extracting the mat from the mat layer 3a to the outside of the furnace, a plurality of (in this case, two) slag tap holes Hb, Hb (see Figure 2) for extracting the slag from the slag layer 3b to the outside of the furnace, and a plurality of (in this case, two) metal tap holes Hc, Hc for extracting the molten metal that remains at the bottom of the mat 3a without sulfidation in the furnace to the outside of the furnace. Incidentally, the structure of the metal tap holes Hc is similar to, for example, the structure of the mat tap holes Ha. The six mat tap holes Ha, Ha, Ha, Ha, Ha, Ha are formed in the front furnace wall 3W. In this front furnace wall 3W, the six mat tap holes Ha, Ha, Ha, Ha, Ha, Ha are arranged horizontally. The two slag tap holes Hb, Hb are formed in a predetermined furnace wall 3W' (hereinafter referred to as "side furnace wall 3W'") located near the uptake 4 along the short side of the settler 3. In this side furnace wall 3W', the two slag tap holes Hb, Hb are arranged horizontally. The two metal tap holes Hc, Hc are formed in the same location as the six mat tap holes Ha, Ha, Ha, Ha, Ha, Ha, Ha, Ha, in the front furnace wall 3W. By making the location of the two metal tap holes Hc, Hc the same location as the location of the six mat tap holes Ha, Ha, Ha, Ha, Ha, Ha, Ha, in this way, access to the two types of tap holes, metal tap hole Hc and mat tap hole Ha, can be made easier. Here, the horizontal position of the metal tap hole Hc is adjusted so that it does not coincide with the horizontal position of the mat tap hole Ha. This is because if the mat tap hole Ha were located directly above the metal tap hole Hc, it would cause problems with the layout of the metal trough connected to the metal tap hole Hc and the mat trough connected to the mat tap hole Ha. In the self-melting furnace 1 described above, the molten metal (slag) extracted from at least one of the two slag tap holes Hb, Hb is transferred to a smelting furnace (not shown) where the matt contained in the molten metal is recovered.The recovered matte is processed in a converter along with molten metal (matte) extracted from at least one of the six matte tap holes Ha, Ha, Ha, Ha, Ha, Ha, and then further refined into higher-grade electrolytic copper. Meanwhile, the molten metal extracted from at least one of the two metal tap holes Hc, Hc is processed in either the slag generation phase or the crude copper generation phase of the converter, depending on at least one of its copper grade or impurity grade. Alternatively, the molten metal extracted from at least one of the metal tap holes Hc, Hc is processed outside the system.

[0039] 1-4. Structure of the furnace bottom The structure of the furnace bottom 1a of the settler 3 will be described below. Figure 4 is a cross-sectional view taken along the line X-X in Figure 1, and Figure 5 is a cross-sectional view taken along the line Y-Y in Figure 1. The X-X cross-section is a cross-section near the center of the non-slope area S1 on the uptake 4 side, and the Y-Y cross-section is a cross-section that intersects with the bottom S2-b of the slope area S2. As shown in Figures 4 and 5, the front furnace wall 3W and the rear furnace wall 3W' of the settler 3 are each composed of a plurality of water-cooled jackets 10, 10, ... connected in a horizontal direction, and the furnace bottom 1a of the settler 3 has a plate-shaped iron shell 1ab, a filled brick area Bi, a lower furnace bottom brick area Bb, and an upper furnace bottom brick area Bu arranged in order from the lower layer, with the upper end surface of the upper furnace bottom brick area Bu used as the hearth S. At both ends of the shorter side of the upper hearth brick area Bb, support sections Bu-e, Bu-e are provided, and at both ends of the shorter side of the lower hearth brick area Bb, support sections Bb-e, Bb-e are provided. Multiple upper hearth bricks with an arch-rise structure are arranged in the upper hearth brick area Bu, multiple lower hearth bricks with an arch-rise structure are arranged in the lower hearth brick area Bb, multiple hearth filling bricks are filled in the filling brick area Bi, multiple or one support bricks are placed in each of the support sections Bu-e, Bu-e, Bb-e, Bb-e, and amorphous refractory material is filled in the gap between the lower hearth brick area Bb and the filling brick area Bi. Note that "support brick" refers to a brick that supports one or the other end of the arch-rise structure.

[0040] 1-5. Details of the Non-Slope Area The details of the non-slope area S1 will be described below with reference to Figure 4. As shown in Figure 4, below the non-slope area S1, multiple upper hearth bricks constituting the upper hearth brick area Bu are assembled in an arch-rise structure, and multiple lower hearth bricks constituting the lower hearth brick area Bb are also assembled in an arch-rise structure, so the cross-sectional shape of the non-slope area S1 is an inverted arch. Furthermore, below the non-slope area S1, the orientation of the upper hearth brick area Bu and the lower hearth brick area Bb is symmetrical with respect to a vertical plane containing the center line extending in the longitudinal direction of the setter 3, and the height position of the upper end of the setter receiving portion Bu-e at one end and the height position of the upper end of the setter receiving portion Bu-e at the other end are the same. Note that in Figure 4, the height position of the upper end of the setter receiving portion Bu-e corresponds to the mat tap hole level La mentioned above.

[0041] 1-6. Details of the Slope Area The details of the slope area S2 will be described below with reference to Figure 5. As shown in Figure 5, below the slope area S2, multiple upper hearth bricks constituting the upper hearth brick area Bu are assembled in an arch-rise structure, and multiple lower hearth bricks constituting the lower hearth brick area Bb are also assembled in an arch-rise structure, so the cross-sectional shape of the slope area S2 is an inverted arch. However, below the slope area S2, the upper hearth brick area Bu and the lower hearth brick area Bb are tilted, and the height position of the upper end of the settling support portion Bu-e on the metal tap hole Hc side (the side of the predetermined furnace wall 3W) is lower than the height position of the upper end of the settling support portion Bu-e on the opposite side of the metal tap hole Hc (the opposite side of the predetermined furnace wall 3W). Moreover, the degree of tilt (amount of tilt) of the slope area S2 depends on the longitudinal position of the settling support 3. Specifically, as shown in Figure 2, in the slope area S1, the tilt amount is set to zero at the boundary line LB with the non-slope area S1, and in the strip-shaped area AB including the bottom S2-b, the tilt amount is set to the maximum, and the tilt amount gradually increases from the boundary line LB to the strip-shaped area AB. In order to secure an appropriate amount of tilt, the thickness of the upper hearth brick area Bu and / or the lower hearth brick area Bb may be thinned as needed in the area of ​​the hearth bottom 1a corresponding to the area below the slope area S2 (especially below the strip-shaped area AB). Also, in the area of ​​the hearth bottom 1a corresponding to the area below the slope area S2, the shapes of the striking support portions Bu-e and Bb-e at both ends of the upper hearth brick area Bu and the lower hearth brick area Bb, and the shapes of the side walls for restraining the striking support portions Bu-e and Bb-e are set to appropriate shapes according to the amount of tilt. In Figure 5, the height of the upper end of the serration receiving portion Bu-e on the metal tap hole Hc side (front furnace wall 3W side) corresponds to the metal tap hole level Lc. The metal tap hole level Lc is approximately 400 mm to 600 mm lower than the metal tap hole level La.

[0042] 1-7. Air Cooling Mechanism Configuration The air cooling mechanism will be described below. Figure 6 is an explanatory diagram illustrating the configuration of the air cooling mechanism located below the furnace bottom. Here, air is assumed as the cooling gas, but the type of gas is not limited to air. As shown in Figure 6, the self-smelting furnace 1 of this embodiment is equipped with an air cooling mechanism 100 as a gas cooling mechanism for cooling the furnace bottom 1a of the settler 3. This air cooling mechanism 100 air cools the furnace bottom 1a for each of the 12 divided areas created by dividing the furnace bottom 1a in the longitudinal direction. The air cooling mechanism 100 includes a metal pipe 101 made of iron or the like, laid directly below the iron shell 1ab of the furnace bottom 1a. This pipe 101 has 12 U-shaped flow paths Fp1, Fp2, ..., Fp12 in plan view, and these 12 flow paths Fp1, Fp2, ..., Fp12 are individually arranged below the 12 divided areas. The inlet sides of these 12 flow paths Fpi (i=1 to 12) are connected to a common manifold duct, and flow rate regulating slide gate dampers 104, 104, ..., 104 are positioned at the inlets of the 12 flow paths Fpi (i=1 to 12). An outlet thermometer 102, an outlet flow meter 103, and a fan 105 are positioned in that order at the outlet side of each of the 12 flow paths Fp1, Fp2, ..., Fp12. Alternatively, instead of connecting the inlet sides of flow paths Fp1 to Fp12 to a common manifold duct, the structure may be modified to directly take in outside air. Furthermore, by connecting the outlets of flow paths Fp1 to Fp12 downstream of the outlet flow meter 103 to a common manifold duct, a single fan 105 may be used for multiple flow paths Fp1 to Fp12.

[0043] 1-8. Heat Removal Measurement Means The heat removal measurement means of the air cooling mechanism 100 will be described below. The air cooling mechanism 100 of this embodiment is equipped with a heat removal measurement means (not shown). The heat removal measurement means measures the amount of heat removed from the furnace bottom 1a for each divided area based on the output of the outlet thermometer 102, the output of the outlet flow meter 103, the temperature of the air on the manifold duct side (for example, assumed to be at room temperature), and known data such as the specific heat of the air. The control unit (not shown) of the air cooling mechanism 100 monitors the amount of heat removed for each divided area measured by the heat removal measurement means, and if there is a divided area where the heat load estimated from the amount of heat removed exceeds a predetermined safety range, the flow rate of cooling air to that divided area is increased by increasing the opening of the slide gate damper 104 corresponding to that divided area. Therefore, it is possible to avoid a situation in which the heat load on a part of the furnace bottom 1a becomes significantly high, and as a result the integrity of the furnace bottom 1a is maintained. On the other hand, the control unit (not shown) of the air cooling mechanism 100 monitors the amount of heat removed from each divided area measured by the heat removal amount measuring means, and if there is a divided area in which the heat load of the furnace bottom 1a estimated from the amount of heat removed falls below the safety range, it reduces the flow rate of cooling air to that divided area by decreasing the opening of the slide gate damper 104 corresponding to that divided area. As a result, it is possible to avoid a situation in which a part of the furnace bottom 1a is supercooled, and as a result, it is possible to prevent the furnace bottom 1a from becoming clogged (a decrease in the furnace volume).

[0044] 1-9. Temperature Measurement Means The temperature measurement means of the air cooling mechanism 100 will be described below. The air cooling mechanism 100 of this embodiment may be equipped with temperature measurement means for measuring the temperature of the furnace bottom 1a in each divided area. Figure 7 is an explanatory diagram illustrating the layout of the temperature measurement means in the X-X cross section of Figure 1, and Figure 8 is an explanatory diagram illustrating the layout of the temperature measurement means in the Y-Y cross section of Figure 1. The X-X cross section is a cross section near the center of the non-slope area S1 on the uptake 4 side, and the Y-Y cross section is a cross section that intersects the bottom S2-b of the slope area S2. As shown in Figures 7 and 8, six thermocouples A, B, C, D, E, and F are attached to each of the twelve divided areas described above, in order from the rear furnace wall 3W'' side, to serve as sensors for the temperature measurement means. The tip (sensor part) of each of the six thermocouples A, B, C, D, E, and F is inserted from below the iron shell 1ab toward the depth of the furnace bottom 1a. The positional relationship of thermocouples B and C is set to be symmetrical with respect to the vertical plane to which the center line extending in the longitudinal direction of the settler 3 belongs, the positional relationship of thermocouples A and D is set to be symmetrical with respect to the same vertical plane, and thermocouples E and F are arranged side by side closer to the front furnace wall 3W''. Of these, the horizontal positions of thermocouples A and B are close together, the horizontal positions of thermocouples C and D are close together, and the horizontal positions of thermocouples E and F are close together. The height of the sensor parts of thermocouples B and C is set to be the same as that of the iron shell 1ab, the height of the sensor part (tip) of thermocouple E is set to be slightly higher than the upper end of the iron shell 1ab, and the height of the sensor parts of thermocouples A, D, and F are all set to be deep within the filled brick area Bi. However, there is a difference in height between the sensor parts of thermocouples A, D, and F that follows the inverted arch shape of the lower furnace bottom brick area Bi. Therefore, the temperature measuring means of this embodiment can measure the temperature of the furnace bottom 1a for each of the 12 divided areas, and can also measure the temperature in detail, especially in the part close to the front furnace wall 3W, even within the same divided area. For example, in the X-X cross section shown in Figure 7, the heights of the sensor parts of thermocouples A to F are set as follows. The following values ​​are the heights of the sensor parts relative to the height of the iron shell 1ab.Thermocouples A and D: 160 mm Thermocouples B and C: 0 mm Thermocouple E: 100 mm Thermocouple F: 225 mm Also, for example, in the Y - Y cross - section shown in FIG. 8, the height positions of the sensor parts of thermocouples A to F are set as follows. The following values are the height positions of the sensor parts based on the height position of the iron sheet 1ab. Thermocouple A: 300 mm Thermocouples D and F: 20 mm Thermocouples B and C: 0 mm Thermocouple E: 100 mm Here, the height position of the sensor part of the thermocouple is set as the deep part of the filled brick area Bi, but it is also possible to set it at other positions such as the lower end of the upper hearth bottom brick area Bu, the inside of the lower hearth bottom brick area Bb, and the lower end of the lower hearth bottom brick area Bb. And the control part of the air - cooling mechanism 100 monitors the temperature of each divided area measured by the temperature - measuring means. When there is a divided area where the heat load of the hearth bottom 1a estimated from that temperature exceeds a predetermined safe range, the opening degree of the slide - gate damper 104 corresponding to that divided area is increased, thereby increasing the flow rate of the cooling air to that divided area. Therefore, it is possible to avoid a situation where the heat load of a part of the hearth bottom 1a becomes extremely high, and as a result, the soundness of the hearth bottom 1a is maintained. On the other hand, the control part of the air - cooling mechanism 100 monitors the temperature of each divided area measured by the temperature - measuring means. When there is a divided area where the heat load of the hearth bottom 1a estimated from that temperature is below the safe range, the opening degree of the slide - gate damper 104 corresponding to that divided area is decreased, thereby decreasing the flow rate of the cooling air to that divided area. Therefore, it is possible to avoid a situation where a part of the hearth bottom 1a is over - cooled, and as a result, it is possible to prevent the filling of the hearth bottom 1a (reduction of the furnace volume).

[0045] 1-10. Slag Tapping The following describes the process of removing slag from the self-smelting furnace 1 of the above-described embodiment (slag tapping). Here, we assume that the self-smelting furnace 1 is in continuous operation. The manager of the self-smelting furnace 1 in this embodiment performs slag tapping, which removes slag from the slag tap hole Hb, almost continuously, and pauses the tapping at a frequency of once every 2 to 3 hours. For example, if the amount of slag produced is approximately 2800 t / d and the slag tapping time is 21 hours out of a day, the slag discharge rate is 130 t / h. By discharging the slag almost continuously at an appropriate rate in this way, it is possible to avoid the surface level of the slag layer 3b exceeding the allowable level for holding molten metal in the furnace.

[0046] 1-11. Mat Tapping The following describes the process of removing mat from the self-smelting furnace 1 of the above-described embodiment (mat tapping). Here again, we assume that the operation of the self-smelting furnace 1 is carried out continuously. The manager of the self-smelting furnace 1 of this embodiment performs mat tapping, which involves removing mat from the mat tap holes Ha, at a frequency of, for example, once every hour. In one mat tapping operation, simultaneous discharge from three of the six mat tap holes Ha takes place over a period of approximately 30 minutes. For example, if the amount of mat produced is approximately 1700 t / d and the mat tapping time is 24 times × 30 minutes per day, the mat discharge rate is 140 t / h (47 t / h per mat tap hole). If the height position of the slag tap hole level Lb is, for example, 800 mm relative to the height position of the mat tap hole level La, the mat molten depth can be kept to, for example, 750 mm or less by the mat tapping of this embodiment. Therefore, the surface level of the mat layer 3a rises, preventing the mat from being discharged from the slag tap hole Hb, and thus preventing a decrease in the copper (Cu) recovery rate.

[0047] 1-12. Metal Tapping The following describes the process of extracting molten metal from the self-smelting furnace 1 of the above-described embodiment (metal tapping). Here again, we assume that the operation of the self-smelting furnace 1 is carried out continuously. 1-12-1. Start Control The manager of the self-smelting furnace 1 of this embodiment starts the process of extracting molten metal from the metal tap hole Hc in the front furnace wall 3W when the surface level of the molten metal reaches the mat tap hole level Ha. For example, the manager of the self-smelting furnace 1 can determine whether the surface level of the molten metal has reached the mat tap hole level Ha by whether or not molten metal has started to be mixed into the mat being extracted from the mat tap hole Ha in the front furnace wall 3W. Alternatively, the operator of the self-smelting furnace 1 can insert a measuring rod through a measuring hole provided in the ceiling of the setter 3 toward the hearth S, and bring the tip of the measuring rod into contact with the hearth S. By determining whether the area of ​​molten metal adhering to the measuring rod reaches the level corresponding to the mat tap hole level Ha, the operator can determine whether the surface level of the molten metal has reached the mat tap hole level Ha. Here, the condition for starting the operation of extracting molten metal from the metal tap hole Hc is defined as "when the surface level of the molten metal reaches the mat tap hole level Ha," but it may also be defined as "when it is predicted that the surface level of the molten metal has reached the mat tap hole level Ha." Such a prediction can be made, for example, based on the composition of raw materials actually fed into the self-smelting furnace 1 and the processing capacity of the self-smelting furnace 1. 1-12-2. Stop Control In this embodiment, the operator of the self-smelting furnace 1 stops the operation of extracting molten metal from the metal tap hole Hc when the surface level of the molten metal drops to a second level lower than the mat tap hole level Ha. For example, the manager of the self-melting furnace 1 can insert a measuring rod through a measuring hole provided in the ceiling of the setter 3 toward the hearth S, and determine whether the surface level of the molten metal has fallen to a second level lower than the mat tap hole level Ha by checking whether the area to which the molten metal adheres to the measuring rod has fallen to a level corresponding to the second level.However, when the operator of the autogenous furnace 1 starts the operation of extracting molten metal from the metal tap hole Hc on the front furnace wall 3W, the operation of extracting the matte from the matte tap hole Ha on the front furnace wall 3W (matte tapping) is stopped. When starting the operation of extracting the matte from the matte tap hole Ha on the front furnace wall 3W, the operation of extracting molten metal from the metal tap hole Hc on the front furnace wall 3W (metal tapping) is stopped. Here, the condition for stopping the operation of extracting molten metal from the metal tap hole Hc is set as "when the surface level of the molten metal has dropped to a second level lower than the matte tap hole level Ha", but it may also be set as "when it is predicted that the surface level of the molten metal has dropped to a second level lower than the matte tap hole level Ha". Such prediction can be made based on, for example, the raw material composition actually charged into the autogenous furnace 1 and the throughput of the autogenous furnace 1.

[0048] 1-13. Other Tapping In addition, the operator of the autogenous furnace 1 of the present embodiment may, for example, perform the operation of extracting all the molten metal, including molten metal, matte, and slag, from the metal tap hole Hc as needed, such as before a long-term shutdown of the autogenous furnace or before renewing the furnace bottom refractory. By extracting the molten metal from the metal tap hole Hc provided at a position lower than the matte tap hole Ha, the residual molten metal in the furnace can be surely removed, so that the melting time of the solidified matter in the furnace at the restart of the operation of the autogenous furnace 1 can be reduced, or the labor for disassembling the solidified matter of the residual molten metal in the furnace before renewing the furnace bottom refractory can be reduced.

[0049] 1-14. Effects of the Embodiment As described above, the self-smelting furnace 1 according to this embodiment is equipped with a slope area S2 that guides molten metal that has accumulated in the lower part of the mat layer 3a without sulfidation toward the front furnace wall 3W, and a metal tap hole Hc that extracts molten metal stored in the bottom S2-b of the slope area S2 to the outside of the furnace, so that the molten metal can be extracted in a timely and smooth manner. Therefore, the following risks can be reduced: (1) the risk of molten metal accumulated in the center of the hearth S of the self-smelting furnace 1 leaking from the bottom 1a of the furnace, (2) the risk of molten metal that has reached the mat tap hole level La melting the copper mat trough, (3) the risk of high-impurity metal being unintentionally supplied to the converter, and (4) the risk of melting the copper water-cooling jacket that constitutes the furnace wall of the self-smelting furnace 1. Furthermore, since the self-smelting furnace 1 of this embodiment is equipped with an air-cooling mechanism 100, even if molten metal accumulates at the bottom S2-b of the slope area S2 for a certain period of time, an appropriate temperature distribution is formed in the height direction of the furnace bottom 1a, thereby reducing the risk of molten metal penetrating into the joints of the furnace bottom bricks and impregnating the furnace bottom bricks. Therefore, molten metal can be stably retained in the furnace of the self-smelting furnace 1. The amount of molten metal retained and the rate at which its retention increases will vary depending on the raw material composition and operating rate of the self-smelting furnace 1. For example, by checking or estimating the amount of molten metal retained once every two hours and discharging the molten metal when the retention amount reaches a certain level, the retention time of the molten metal at the bottom S2-b of the slope area S2 can be kept within a safe range. For example, if the rate of increase of the amount of molten metal remaining in the bottom S2-b is 2 t / h, the molten metal can be discharged from the furnace before the melting point decreases by either discharging the molten metal every 12 hours (when the amount reaches approximately 24 t, which is half a day's worth) or by discharging the molten metal when it is measured to have reached a depth of 100 mm. As a result, the risk of penetration into the joints of the furnace bottom bricks and the risk of impregnation into the furnace bottom bricks can be reduced.Furthermore, the air cooling mechanism 100 of this embodiment adjusts the air cooling intensity for each divided area of ​​the furnace bottom 1a, so that a portion of the divided area where molten metal accumulates (below the slope area S2) can be concentrated with air cooling. Therefore, the heat load of each of the 12 divided areas of the furnace bottom 1a can be kept within a safe range, achieving both the maintenance of the integrity of the furnace bottom 1a and the prevention of volume reduction due to supercooling. Moreover, the self-smelting furnace 1 of this embodiment can be easily realized by simply modifying the arch rise structure and smelting support structure of the furnace bottom of a conventional self-smelting furnace. In addition, the self-smelting furnace 1 of this embodiment can tap molten metal horizontally from the metal tap hole Hc, so it is safer compared to the case where molten metal is tapped from the bottom. Furthermore, the self-smelting furnace 1 of this embodiment can be operated in the same way as a conventional self-smelting furnace when the proportion of recycled material mainly consisting of metal is small.

[0050] 2. Modifications of the Self-Smelting Furnace and its Operating Method 2-1. Regarding the Handling of Casting In the above-described embodiment, if the operation of the self-smelting furnace 1 is continued, a magnetite-based casting may form at the bottom of the slope area S2, potentially reducing the volume available for storing molten metal at the bottom (recess) of the slope area S2. In such cases, the self-smelting furnace 1 may be operated under conditions in which molten metal is not generated (for example, under conditions in which recycled raw materials mainly composed of copper metal are not introduced), thereby allowing the mat to accumulate at the bottom of the slope area S2. At the same time, a reducing agent such as iron particles (Fe particles) may be introduced into the furnace to reduce the magnetite and restore the volume at the bottom (recess) of the slope area S2.

[0051] 2-2. Regarding metal tap holes: In the above embodiment or modified example, the number of metal tap holes Hc is set to 2, but a number other than 2 may be used.

[0052] 2-3. Regarding the divided areas, in the above embodiment or modified example, the number of divided areas in the furnace bottom 1a was set to 12, but a number other than 12 may be used.

[0053] 2-4. Regarding the air cooling mechanism In the above embodiment or modified example, the control unit of the air cooling mechanism 100 controlled the temperature of each divided area of ​​the furnace bottom 1a based on either the amount of heat removed measured by the heat removal amount measuring means or the temperature measured by the temperature measuring means, but it may also be based on both. For example, the control unit of the air cooling mechanism 100 may improve the accuracy of the amount of heat removed measured by the heat removal amount measuring means based on the temperature measured by the temperature measuring means, and control the temperature of each divided area based on the more accurate amount of heat removed. For example, the control unit of the air cooling mechanism 100 may determine whether or not it is necessary to open or close the slide gate damper 104 corresponding to a certain divided area based on the amount of heat removed measured from that divided area, and determine the degree of opening of the slide gate damper 104 corresponding to that divided area based on the temperature measured from that divided area.

[0054] 2-5. Operating Conditions of the Self-Smelting Furnace In the embodiments or modifications of the self-smelting furnace operating method described above, the operating conditions of the self-smelting furnace 1 may be set so that the partial pressure of oxygen (atm) inside the self-smelting furnace 1 during operation falls within the range of 10 to the power of -10 to the power of -6. For example, the partial pressure of oxygen (atm) inside the reaction shaft 2 is about 10 to the power of -8, and in the case of free air entering the furnace, the operating conditions of the self-smelting furnace 1 are set so that the partial pressure of oxygen (atm) inside the setter 3 is about 10 to the power of -7.

[0055] Furthermore, in the embodiments or modifications of the self-smelting furnace operation method described above, the operating conditions of the self-smelting furnace 1 may be set so that the copper content (weight %) of the mat extracted from the self-smelting furnace 1 (self-smelting furnace mat) is in the range of 50% to 70%. For example, in order to make the copper content (weight %) of the self-smelting furnace mat extracted from the self-smelting furnace 1 65%, the operating conditions of the self-smelting furnace 1 are set so that the copper content (weight %) of the mat generated in the furnace of the reaction shaft 2 is slightly lower (for example, 59%) than the target value (65% in this case).

[0056] Furthermore, in the embodiments or modifications of the self-smelting furnace operation method described above, the operating conditions of the self-smelting furnace 1 may be set such that the copper content (weight %) in the molten metal inside the furnace is in the range of 50% to 100%, and the concentration of impurity elements (iron, tin, lead) in the molten metal is in the range of 0% to 50%. For example, the operating conditions of the self-smelting furnace 1 may be set such that the copper content (weight %) in the molten metal is in the range of 70% to 90%.

[0057] Furthermore, operating conditions that can be adjusted to keep the copper grade of the self-smelting furnace mat extracted from the mat tap hole Ha of the self-smelting furnace 1 within an appropriate range, and the copper grade of the molten metal extracted from the metal tap hole Hc of the self-smelting furnace 1 within an appropriate range, include, for example, the composition of the raw materials supplied to the self-smelting furnace 1. Since the raw materials supplied to the self-smelting furnace 1 as described above include at least metal-based recycled materials (hereinafter simply referred to as "recycled materials") and copper concentrate, the composition of the raw materials can be adjusted by adjusting the weight ratio of the recycled materials, the types of recycled materials, the combination of types of recycled materials, the weight ratio of each type of recycled material, etc.

[0058] Furthermore, if the weight ratio of recycled materials supplied to the self-smelting furnace 1 is high and the molten metal temperature inside the furnace of the self-smelting furnace 1 decreases due to insufficient heat of reaction, the molten metal temperature inside the furnace may be increased by heat supplementation using fossil fuels, hydrogen, electrodes, or a combination thereof. In addition, the heat balance inside the furnace may be adjusted by increasing the oxygen concentration of the reaction gas blown into the self-smelting furnace 1 or by decreasing the amount of non-exothermic substances supplied to the self-smelting furnace 1.

[0059] Furthermore, the recycled material supplied to the self-melting furnace 1 may include at least one of the following (1) to (5): (1) Particulate material that has been incinerated and finely ground, ranging in size from several micrometers to several hundred micrometers (2) Particulate material that has been finely ground without being incinerated, ranging in size from several micrometers to several hundred micrometers (3) Granular material that has been ground in the fine grinding process, ranging in size from several millimeters to tens of millimeters (4) Granular material that has not undergone the fine grinding process, ranging in size from several millimeters to tens of millimeters (5) Particulate material that has been ground in the fine grinding process, ranging in size from several micrometers to several hundred micrometers. In this specification, micrometer-sized material is referred to as "particulate material," and millimeter-sized material is referred to as "granular material."

[0060] Furthermore, during the operation of the self-smelting furnace 1, the pretreatment conditions of the recycled raw material (e.g., the degree and presence or absence of pulverization treatment) may be adjusted according to the content of impurity elements in the recycled raw material. If this adjustment is performed appropriately, the oxidation of impurities (tin, lead, chromium, etc.) in the recycled raw material can be promoted in both the process of passing through the slag layer of the self-smelting furnace 1 and the process of passing through the intermediate layer at the boundary between the slag layer and the mat layer, making it easier for impurities (tin, lead, chromium, etc.) to be incorporated into the self-smelting furnace slag. As a result, it becomes possible to efficiently remove impurities from the system in the self-smelting furnace 1.

[0061] 3. The copper smelting method will now be described in the following section, which will be an embodiment of the copper smelting method using the embodiment or modified version of the self-smelting furnace operation method described above. According to the copper smelting method of this embodiment, it is possible to stably process recycled raw materials that contain an amount of metal components exceeding the self-smelting furnace 1's ability to mattify the metal components.

[0062] 3-1. Conventional Copper Smelting Method First, for comparison, we will explain the conventional copper smelting method. Figure 9 is a schematic diagram illustrating the flow of the conventional copper smelting method. As shown in Figure 9, the conventional copper smelting method uses a conventional self-smelting furnace 201, a converter 203, a slag smelting furnace 202, etc. The raw materials supplied to the self-smelting furnace 201 are, for example, a combination of copper concentrate and recycled raw materials, and the weight ratio of recycled raw materials in the total raw materials supplied to the self-smelting furnace 201 is about 8 to 10 wt%. The converter 203 is the first downstream furnace that processes the self-smelting furnace mat, which is the mat extracted from the mat tap hole of the conventional self-smelting furnace 201. The slag smelting furnace 202 is the second downstream furnace that processes the self-smelting furnace slag, which is the slag extracted from the slag tap hole of the conventional self-smelting furnace 201. Incidentally, this slag smelting furnace 202 is sometimes called a "slag cleaning furnace". The self-smelting furnace slag supplied to the smelting furnace 202 is separated within the furnace into a copper-containing mat, known as the smelting furnace mat (an example of the second mat), and smelting furnace slag (an example of the second slag) present on top of the smelting furnace mat. The separated smelting furnace slag is discharged from the system, and the smelting furnace mat is supplied to the converter 203. The self-smelting furnace mat and smelting furnace mat supplied to the converter 203 are oxidized within the converter 203, separating them into crude copper from which impurities have been removed and converter slag containing impurities. The crude copper from which impurities have been removed is purified in a refining furnace (not shown) and then sent to a subsequent electrolytic refining process to produce electrolytic copper, a copper product. In this conventional copper smelting method, there is a limit to the amount of recycled material that can be processed in the self-smelting furnace 201, so the processing shown by the thick black arrow in Figure 9 (hereinafter referred to as the "repeated route") is carried out. In this repeating route, for example, a portion of the recycled raw materials to be processed in the copper smelting process is supplied to the converter 203. After the converter slag generated in the converter 203 is solidified and crushed, it is separated into an Fe-rich phase and a Cu-rich phase by flotation. The Cu-rich phase is returned to the self-smelting furnace 201, while the Fe-rich phase is discharged from the system. In this repeating route, it is also possible to return the converter slag generated in the converter 203 to the self-smelting furnace 201 as molten metal (without going through the solidification, crushing, and flotation processes).Incidentally, converter slag processed through this repeated route is sometimes called "recycled slag."

[0063] 3-2. Embodiment of the Copper Smelting Method Next, an embodiment of the copper smelting method will be described. Figure 10 is a schematic diagram illustrating the flow of an embodiment of the copper smelting method. Here, we will mainly explain the differences from the conventional smelting method shown in Figure 9, and omit the explanation of the common points. In the copper smelting method of this embodiment, as shown in Figure 10, a self-smelting furnace 1 according to the above-described embodiment or modified example is used. The raw materials supplied to this self-smelting furnace 1 are also a combination of copper concentrate and recycled raw materials. However, in the copper smelting method of this embodiment, it is assumed that the weight ratio of recycled raw materials in the total raw materials supplied to the self-smelting furnace 1 is, for example, 10 to 35 wt%, and the weight ratio of particulate raw materials to particulate raw materials in the recycled raw materials is greater than "1" (there are more granular raw materials than particulate raw materials). With such a weight ratio, the molten metal derived from recycled raw materials tends to settle in the furnace of the self-smelting furnace 1, so a large amount of molten metal can be recovered from the metal tap hole Hc. The molten metal extracted from the metal tap hole Hc of the self-smelting furnace 1, along with the self-smelting furnace mat extracted from the mat tap hole Ha of the self-smelting furnace 1, is supplied to the converter 203, which acts as the first downstream furnace. Therefore, the copper contained in the molten metal, along with the copper contained in the self-smelting furnace mat, is recovered as crude copper in the converter 203 (see the recovery route indicated by the thick white arrow in Figure 10). The converter slag generated in the converter 203 is processed using the same repeating route as in the conventional method (the thick black arrow in Figure 10). Thus, according to the copper smelting method of this embodiment, the route for transferring the molten metal in the self-smelting furnace 1 to the converter 203 (the thick white arrow in Figure 10) is utilized, making it possible to increase the amount of recycled material supplied to the self-smelting furnace 1 while ensuring the safety of the self-smelting furnace 1. Furthermore, according to the copper smelting method of this embodiment, impurities in the self-smelting furnace 1 can be efficiently transferred to the self-smelting furnace slag side, thereby reducing the amount of impurities mixed into the self-smelting furnace mat side. As a result, the amount of impurities in the crude copper produced in the converter 203 and the amount of impurities in the converter slag are both reduced. Meanwhile, the self-smelting furnace slag extracted from the slag tap hole Hb of the self-smelting furnace 1 is supplied to the smelting furnace 202. The self-smelting furnace slag supplied to the smelting furnace 202 is separated into a smelting furnace mat containing copper (an example of a second mat) and smelting furnace slag present on top of the smelting furnace mat (an example of a second slag).The separated furnace slag is discharged outside the system, and the separated furnace mat is supplied to the converter 203. However, if a large amount of recycled material is supplied to the self-smelting furnace 1, the concentration of impurities such as Al and Cr in the self-smelting furnace slag will increase, which may lead to a deterioration in the fluidity of the self-smelting furnace slag and a deterioration in operability. Therefore, in the copper smelting method of this embodiment, when separating the self-smelting furnace slag into furnace mat and furnace slag by the furnace 202 (or slag cleaning furnace), at least one of the following steps may be performed: (1) reduction of the furnace slag, (2) heating of the furnace slag, or (3) supply of additives to modify the furnace slag. At least one of these steps can improve the fluidity of the furnace slag. In addition, in the copper smelting method of this embodiment, a ladle, a trough, or a combination thereof can be used to transfer the molten metal from the self-smelting furnace 1 to the converter 203. Furthermore, when transferring the molten metal with a ladle, its storability and ease of transfer may be improved by solidifying the molten metal in the ladle before supplying it to the converter 203.

[0064] 3-3. Second Embodiment of the Copper Smelting Method Next, a second embodiment of the copper smelting method described above will be explained. Figure 11 is a schematic diagram illustrating the flow of the second embodiment of the copper smelting method. Here, we will mainly explain the differences from the embodiment of the copper smelting method shown in Figure 10, and omit the explanation of the common points. In the copper smelting method of the second embodiment, as shown in Figure 11, a self-smelting furnace 1 is also used, but it differs from the copper smelting method of the first embodiment in that a smelting furnace 202' is used instead of a smelting furnace 202. In the copper smelting method of the second embodiment, the raw materials supplied to the self-smelting furnace 1 are a combination of copper concentrate and recycled raw materials, and the weight ratio of recycled raw materials in the total raw materials supplied to the self-smelting furnace 1 is, for example, 10 to 35 wt%. However, in the copper smelting method of the second embodiment, it is assumed that the weight ratio of granular raw materials to particulate raw materials in the recycled raw materials supplied to the self-smelting furnace 1 is less than "1" (there are fewer granular raw materials than particulate raw materials). With this weight ratio, the molten metal is less likely to settle in the furnace of the self-smelting furnace 1, so it is thought that the molten metal that does not reach the molten metal layer in the furnace of the self-smelting furnace 1 (reference numeral 3c in Figure 1) will be mixed into the self-smelting furnace mat and self-smelting furnace slag. However, in the copper smelting method of the second embodiment, the mixing of molten metal into the self-smelting furnace mat is permitted. This is because the self-smelting furnace mat mixed with molten metal is supplied to the converter 203, so the copper contained in that molten metal can be recovered (see the recovery route indicated by the thick white arrow on the left side of Figure 11). Furthermore, in the copper smelting method of the second embodiment, the mixing of molten metal into the self-smelting furnace slag is also permitted. Instead, in the copper smelting method of this embodiment, the self-smelting furnace slag mixed with molten metal is supplied to the smelting furnace 202', and sufficient time is provided when separating the self-smelting furnace slag into the smelting furnace slag and the smelting furnace mat present beneath it, thereby allowing the molten metal mixed with the self-smelting furnace slag to settle on the hearth of the smelting furnace 202'. Then, the settled molten metal is supplied to the converter 203 together with the smelting furnace mat to recover the copper contained in the molten metal (see the recovery route indicated by the thick white arrow on the right side of Figure 11).In addition, the second embodiment of the smelting furnace 202' may be provided with a metal tap hole Hf for extracting molten metal, in addition to the mat tap hole Hd for extracting the smelting furnace mat and the slag tap hole He for extracting the smelting furnace slag. This configuration of the smelting furnace 202' allows for the efficient extraction of both the molten metal settled on the hearth of the smelting furnace 202' and the smelting furnace mat present on top of it. In the copper smelting method of the second embodiment, the weight ratio of particulate material and granular material in the recycled material supplied to the self-smelting furnace 1 may be adjusted to balance the amount of molten metal extracted from the smelting furnace 202' and the amount of molten metal extracted from the self-smelting furnace 1. For example, to increase the amount of molten metal extracted from the smelting furnace 202', the weight ratio of particulate material in the recycled material supplied to the self-smelting furnace 1 may be increased, or to increase the amount of molten metal extracted from the self-smelting furnace 1, the weight ratio of particulate material in the recycled material supplied to the self-smelting furnace 1 may be decreased. As a method for adjusting the weight ratio of particulate materials in recycled materials, methods such as adjusting the pretreatment conditions of the recycled materials (e.g., the degree and presence or absence of pulverization treatment) can be employed. In addition, although a smelting furnace 202' with a metal tap hole Hf was used in the copper smelting method of the second embodiment, a smelting furnace 202 similar to the one shown in Figure 10 may be used as long as the settled molten metal and smelting furnace mat can be properly extracted. Note that if a large amount of recycled material is supplied to the self-smelting furnace 1, the concentration of impurities such as Al and Cr in the self-smelting furnace slag will increase, which may lead to a deterioration in the fluidity of the self-smelting furnace slag and a deterioration in operability, as well as a deterioration in the settling ability of the metal components suspended in the self-smelting furnace slag. Therefore, in the copper smelting method of the second embodiment, similar to the copper smelting method of the embodiment described above, when separating the self-smelting furnace slag into a furnace mat and furnace slag using the furnace 202 (or slag cleaning furnace), at least one of the following steps may be performed: (1) reduction of the furnace slag, (2) heating of the furnace slag, or (3) supply of additives to modify the furnace slag.By performing at least one of these steps, the fluidity of the furnace slag can be improved, and the suspension loss of the furnace slag (the loss of mat and metal that remain suspended in the furnace slag without being recovered) can be reduced.

[0065] 3-3-1. Modification 1 of the Second Embodiment of the Copper Smelting Method Below, Modification 1 of the second embodiment will be described. Here, the differences from the second embodiment will be mainly explained, and the explanation of the common points will be omitted. The copper smelting method according to Modification 1 includes a step of separating the self-smelting furnace slag into a furnace mat and furnace slag using a furnace smelting furnace. During this separation, at least one of the following steps is performed: (1) reduction of the furnace slag, (2) heating of the furnace slag, (3) supply of additives to modify the furnace slag, (4) oxidation of the furnace slag, (5) oxidation of the furnace mat, or (6) heating of the furnace mat. As a result, at least one of the following effects can be obtained: sedimentation separation of the mat suspended in the furnace slag, removal of impurity elements from the furnace slag, or transfer of components other than copper in the furnace mat to the furnace slag.

[0066] 3-3-2. Modification 2 of the Second Embodiment of the Copper Smelting Method Below, Modification 2 of the Second Embodiment will be described. Here, the differences from Modification 1 will be mainly explained, and the explanation of the common points will be omitted. The copper smelting method according to Modification 2 includes a step of separating the self-smelting furnace slag into furnace slag and molten metal using a smelting furnace. During this separation, at least one of the following steps is performed: (1) reduction of the furnace slag, (2) heating of the furnace slag, (3) supply of additives to modify the furnace slag, (4) oxidation of the furnace slag, or (7) oxidation of the molten metal. As a result, at least one of the following effects can be obtained: sedimentation separation of the molten metal suspended in the furnace slag, transfer of impurity elements in the furnace slag into the metal, removal of impurity elements from the furnace slag, or transfer of components other than copper in the molten metal into the furnace slag.

[0067] 3-3-3. Modification 3 of the Second Embodiment of the Copper Smelting Method Below, Modification 3 of the Second Embodiment will be described. Here, the differences from Modification 1 or Modification 2 will be mainly explained, and the explanation of the common points will be omitted. Modification 3 is a combination of Modification 1 and Modification 2, and includes a step of separating the self-smelting furnace slag into a furnace mat, furnace slag, and molten metal using a smelting furnace. During this separation, at least one of the following steps is performed: (1) reduction of furnace slag, (2) heating of furnace slag, (3) supply of additives to modify furnace slag, (4) oxidation of furnace slag, (5) oxidation of furnace mat, (6) heating of furnace mat, or (7) oxidation of molten metal. As a result, the distribution state of the components contained in the furnace mat, furnace slag, and molten metal to each phase can be controlled. Specifically, at least one of the following effects can be obtained: sedimentation separation of the furnace mat and molten metal suspended in the furnace slag; transfer of impurity elements from the furnace slag to the furnace mat and furnace metal; removal of impurity elements from the furnace slag; transfer of impurity elements from the furnace slag to the gas phase that shares an interface with the slag; or transfer of components other than copper from the furnace mat and molten metal to the furnace slag.

[0068] 3-4. Supplementary Information on the Copper Smelting Method In the embodiments or modifications of the copper smelting method described above, the following (1) to (6) shall be appropriately controlled in accordance with the operating cycle of the converter 203: (1) Timing for removing the self-smelting furnace mat, self-smelting furnace slag, and molten metal from the self-smelting furnace 1; (2) Amount of self-smelting furnace mat, self-smelting furnace slag, and molten metal removed from the self-smelting furnace 1; (3) Timing for removing the smelting furnace mat from the smelting furnace 202; (4) Amount of smelting furnace mat removed from the smelting furnace 202; (5) Timing for removing the smelting furnace mat and molten metal from the smelting furnace 202'; (6) Amount of smelting furnace mat and molten metal removed from the smelting furnace 202'.

[0069] 4. The present invention is not limited to each embodiment, and its components can be modified and implemented without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in each embodiment. For example, some components may be deleted from all components shown in an embodiment. Furthermore, components from different embodiments may be appropriately combined. Although embodiments relating to a self-smelting furnace as a copper smelting furnace and its operating method have been described, the present invention is also applicable to the smelting of metals other than copper. According to one embodiment of the present invention, it may contribute to Goal 9 of the United Nations Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," through contributions to technological innovation in copper smelting. Also, according to one embodiment of the present invention, it may contribute to Goal 12 of the United Nations Sustainable Development Goals (SDGs), "Ensure sustainable consumption and production patterns," through the promotion of the use of recycled materials.

[0070] 1 Self-smelting furnace 10 Water-cooled jacket 101 Piping 102 Outlet thermometer 103 Outlet flow meter 104 Slide gate damper 105 Fan 1a Furnace bottom 1a Furnace bottom 1ab Iron shell 2 Reaction shaft 3 Settler 3W Front furnace wall 3W' Side furnace wall 3W” Rear furnace wall Ha Mat tap hole 3a Mat layer 3b Slag layer 3c Molten metal layer 4 Uptake 7 Concentrate burner 8 Oxygen-enriched air supply section Bb Lower area Bb-e Slag receiving section Bi Filling area Bu Upper area Bu-e Slag receiving section Fp1-Fp12 Flow path Hb Slag tap hole Hc Metal tap hole La Mat tap hole level Lb Slag tap hole level Lc Metal tap hole level S Hearth S1 Non-slope area S1-u Top S1-b Bottom S2 Slope area S2-b Bottom 201 Self-smelting furnace (conventional self-smelting furnace) 202 Alchemy furnace (example of second-stage furnace) 202' Alchemy furnace (example of second-stage furnace) 203 Converter (example of first-stage furnace) Hd Matt tap hole He Slag tap hole Hf Metal tap hole

Claims

1. A self-smelting furnace that separates a high-temperature melt produced by reacting raw materials with oxygen in a reaction shaft into a mat layer containing a mat, which is a sulfide of a predetermined metal, and a slag layer present on the mat layer, on the hearth of a settler, characterized by comprising: a predetermined slope area provided on the hearth to guide the molten metal, which is the molten material of the predetermined metal that remains at the bottom of the mat layer without sulfidation, toward the side of the furnace wall of the settler; and a metal tap hole formed in the furnace wall to extract the molten metal stored at the bottom of the slope area to the outside of the furnace.

2. The self-smelting furnace according to claim 1, characterized in that the range in which the slope area is formed is a predetermined range below the reaction shaft.

3. A self-smelting furnace according to claim 2, wherein the hearth of the setter is the upper end surface of a brick array with a round bottom shape and an inverted arch cross-section, and the cross-sectional shape of the slope area of ​​the hearth is an inverted arch tilted such that the height position of the settling support on the metal tap hole side is lower than the height position of the settling support on the opposite side of the metal tap hole.

4. The self-smelting furnace according to claim 3, characterized in that the cross-sectional shape of the non-slope area of ​​the hearth is an inverted arch shape in which the height position of one smelting support portion and the height position of the other smelting support portion are the same.

5. A self-smelting furnace according to claim 3, characterized in that the height position of the bottom of the slope area of ​​the hearth is lower than the height position of the bottom of the non-sloping area of ​​the hearth.

6. A self-smelting furnace according to claim 3, characterized in that the height position of the mat tap hole in the furnace wall is set to the height position of the serration receiving portion in the non-slope area, and the height position of the metal tap hole in the furnace wall is set to the height position of the serration receiving portion on the metal tap hole side of the slope area.

7. A self-smelting furnace according to claim 6, characterized in that the horizontal position of the metal tap hole in the furnace wall is adjusted so as not to be the same as the horizontal position of the mat tap hole in the furnace wall.

8. A self-smelting furnace according to claim 1, further comprising a gas cooling mechanism for cooling the furnace bottom of the settler area by area.

9. A self-smelting furnace according to claim 8, further comprising a heat removal amount measuring means for measuring the amount of heat removed by the gas cooling mechanism for each area of ​​the furnace bottom.

10. A self-smelting furnace according to claim 8, further comprising a temperature measuring means for measuring the temperature of the furnace bottom of the settler for each area of ​​the furnace bottom.

11. A method for operating a self-smelting furnace according to any one of claims 1 to 10, characterized in that the operation of extracting the molten metal from the metal tap holes in the furnace wall is started when the surface level of the molten metal reaches the level of the mat tap holes or when this is predicted.

12. A method for operating a self-smelting furnace according to claim 11, characterized in that it is determined whether the surface level of the molten metal has reached the level of the mat tap hole by whether or not the molten metal has begun to be mixed into the mat that is pulled out from the mat tap hole of the furnace wall.

13. A method for operating a self-melting furnace according to claim 11, characterized in that the surface level of the molten metal reaches the mat tap hole level by determining whether the area to which the molten metal adheres to a measuring rod inserted through the measuring hole of the setter reaches the level corresponding to the mat tap hole level.

14. A method for operating a self-melting furnace according to claim 11, characterized in that the operation of extracting the molten metal from the metal tap hole is stopped when the surface level of the molten metal falls to a second level lower than the mat tap hole level, or when this is predicted.

15. A method for operating a self-melting furnace according to claim 14, characterized in that the surface level of the molten metal has decreased to the second level by determining whether the area to which the molten metal adheres to a measuring rod inserted through the measuring hole of the setter has decreased to the level corresponding to the second level.

16. A method for operating a self-smelting furnace according to claim 11, characterized in that when the operation of removing the molten metal from the metal tap hole is started, the operation of removing the mat from the mat tap hole in the furnace wall is stopped, and when the operation of removing the mat from the mat tap hole in the furnace wall is started, the operation of removing the molten metal from the metal tap hole is stopped.

17. A method for operating a self-smelting furnace according to claim 11, characterized in that, as necessary, the operation of removing all molten metal, including the molten metal, the mat, and the slag, from the metal tap hole is performed.

18. A method for operating a self-smelting furnace according to claim 9 or 10, characterized in that if there is an area where the heat load estimated from the amount of heat removed or the temperature exceeds a predetermined range, the flow rate of the cooling gas to that area is increased.

19. A method for operating a self-smelting furnace according to claim 18, characterized in that if there is an area where the heat load estimated from the amount of heat removed or the temperature falls below the predetermined range, the flow rate of the cooling gas to that area is reduced.

20. A metal smelting method using a self-smelting furnace as described in claim 1, characterized in that molten metal extracted from the metal tap hole of the self-smelting furnace is supplied to a first downstream furnace together with the self-smelting furnace mat extracted from the mat tap hole of the self-smelting furnace.

21. A metal smelting method according to claim 20, characterized in that the self-smelting furnace slag extracted from the slag tap hole of the self-smelting furnace is supplied to a second downstream furnace, thereby separating it into a second mat containing the metal and a second slag present on the second mat, and the second mat is supplied to the first downstream furnace.

22. A metal smelting method according to claim 21, characterized in that when separating the self-smelting furnace slag into the second mat and the second slag using the second downstream furnace, at least one of the following steps is performed: reduction of the second slag, heating of the second slag, or supply of an additive for modifying the second slag.

23. A metal smelting method according to claim 21, characterized in that molten metal is allowed to be mixed into the self-smelting furnace mat, and the self-smelting furnace mat mixed with the molten metal is supplied to the first downstream furnace.

24. A metal smelting method according to claim 21, characterized in that molten metal is allowed to be mixed into the self-smelting furnace slag, the self-smelting furnace slag mixed with the molten metal is supplied to the second downstream furnace, the molten metal is allowed to settle on the hearth of the second downstream furnace, and the settled molten metal is supplied to the first downstream furnace together with the second mat.

25. A metal smelting method according to claim 24, characterized in that, during the operation of the second downstream furnace, at least one of the following steps is performed: reduction of the second slag, heating of the second slag, supply of additives for modifying the second slag, oxidation of the second slag, oxidation of the second matte, heating of the second matte, or oxidation of the molten metal.

26. A metal smelting method according to claim 24, wherein the raw materials include recycled materials, and the weight ratio of particulate materials and granular materials in the recycled materials is adjusted in order to adjust the balance between the amount of molten metal extracted from the second downstream furnace and the amount of molten metal extracted from the self-smelting furnace.

27. A metal smelting method according to claim 26, characterized in that the pretreatment conditions of the recycled raw materials are adjusted in order to adjust the weight ratio.

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