Abstract:
The present invention relates to facilities for feeding shredder dusts to a reverberatory furnace in which shredder dusts is fed to a reverberatory furnace for non-ferrous smelting, and in particular, to facilities for feeding shredder dusts to a reverberatory furnace in which a feeding chute that passes to the inside of the reverberatory furnace is fitted to the ceiling of the reverberatory furnace and shredder dusts can be fed from this feeding chute, and which also allows oxygen enriched air to be supplied to the feeding chute and fed to the inside of the reverberatory furnace. Further, the present invention relates to a reverberatory furnace for non-ferrous smelting in which a burner is able to be installed in a wall portion of one end side thereof, and in particular, to a reverberatory furnace for non-ferrous smelting in which a plurality of feeding ports to which are connected the feeding chutes of the shredder dusts feeding facilities are provided at the one end side in the ceiling portion thereof forming a plurality of staggered rows facing the other end side.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a feeding facilities for shredder dusts for performing an incinerating process by burning shredder dusts comprising various shredded waste materials by feeding the shredder dusts to a reverberatory furnace for non-ferrous smelting and to a reverberatory furnace provided with this feeding facilities.  
           [0003]    2. Description of the Related Art  
           [0004]    In recent years the processing of industrial waste materials has become a problem for society. Currently, the landfilling of waste materials is severely restricted and incineration methods are also regulated so as to prevent dioxin from being generated. In this situation, in order to recover various metals such as copper, gold, silver, and palladium without generating dioxin, the inventors of the present invention attempted the processing of automobile shredder dusts in a reverberatory furnace. Here, the term shredder dusts is used to refer generally to fluff materials coming out when scrapped vehicles are crushed in order to recover steel and aluminum. Shredder dusts is more easily burnt than chipped tires and also contains valuable metals; therefore, the processing ratio of such attempts is continually improving.  
           [0005]    A schematic flow chart of the processing of automobile shredder dusts in a reverberatory furnace is shown in FIG. 9. In this flow chart, the reverberatory furnace  1  is a green charge type (wet charge type) reverberatory furnace used for non-ferrous smelting and in particular for smelting copper concentrates. Industrial waste materials such as automobile shredder dusts are stored in the stockyard  2 , then transported to the reverberatory furnace  1  by conveyors  4  from the feed hopper  3  and fed into the inside of the reverberatory furnace  1  by a feeding chute composed by such as a steel pipe. The industrial waste materials are then processing in the reverberatory furnace  1  together with copper concentrates. Oxygen enriched air is also supplied to the reverberatory furnace  1  from an oxygen plant  5 .  
           [0006]    Moreover, the off-gas from the reverberatory furnace  1  is cooled through a waste heat boiler  6  for recovering heat and, then the dust in the off-gas has been collected by an electrostatic precipitator  7 , SO 2  in the gas is fixed as gypsum by a gypsum plant  8 . Note that the steam generated in the waste heat boiler  6  is used to electrical power in a turbine generator  9 , however, the amount of generated power corresponds to approximately half of the total amount of power consumption at the smelter. On the other hand, in the period when the converter is operating, dried copper concentrates and oxygen from the oxygen plant  5  are fed into the converter  10  and the off-gas is fed to the sulfuric acid plant  13  via the boiler  11  and the electrostatic precipitator  12 . Moreover, an anode produced from the converter  10  via an anode furnace  14  is changed to electrolytic copper in a tank house (electro-refining plant)  15 . In this tank house  15 , gold, silver, and palladium are collected as anode slime.  
           [0007]    As the present inventors were continuing the above described attempts, they noticed that there were several problems that needed to be resolved arising from the burning of shredder dusts in the reverberatory furnace  1  in the above described manner. One of these problems was that the amount of shredder dusts to be processed in the reverberatory furnace  1  was limited by the volume of off-gas expelled from the reverberatory furnace  1 . Namely, if the atmosphere inside the reverberatory furnace  1  becomes insufficient in oxygen due to the off-gas generated in the burning of the shredder dusts previously supplied or to the burning off-gases caused by fuel directly fed from the burner into the reverberatory furnace  1  and burnt therein, then even if new shredder dusts is fed into the reverberatory furnace  1 , this cannot be easily burnt and simply accumulates in an unprocessed state inside the reverberatory furnace  1 .  
           [0008]    Moreover, as described above, the shredder dusts is stored the stockyard  2  of the smelter, transported by the conveyor  4  from the feed hopper  3 , then fed to the inside of the reverberatory furnace  1  via a feeding chute. However, for example, if the feeding chute is simply installed in the ceiling of the reverberatory furnace  1  and the shredder dusts simply fed into this chute, the off-gases increase and in cases in which it is not possible to maintain a sufficient negative draft inside the reverberatory furnace  1 , there is the concern that the off-gas inside the furnace and the gas from the burning will leak out by the feeding chute. Since the sealing needs to be so secure that the gas inside the furnace does not leak even when the shredder dusts is being fed, it is necessary to provide a double damper, for example, which results, of course, in the operation of feeding the shredder dusts becoming complicated, but also means that continuous feeding is difficult. The ultimate result is that restrictions are placed on the amount of shredder dusts that can be processed.  
           [0009]    Another problem is that if shredder dusts remains as unburnt condition when the shredder dusts is charged to the reverberatory furnace  1 , this unburnt shredder dusts piles up in the reverberatory furnace  1  forming small hills (piles) in the furnace. If the dimension of these piles increases, the clearance between them and the ceiling of the reverberating furnace  1  becomes smaller. As a result, when new shredder dusts is fed to the top of the pile, the hot-gas goes out of the reverberatory furnace  1  through the feeding chute positioned directly above the flames, creating the concern that the conveyor belt used for transporting the shredder dusts may be burnt. Moreover, particularly if these large piles are formed nearby the burners inside the reverberatory furnace  1 , then the burning condition of the burners is disturbed which naturally results in the burning of the shredder dusts not being possible, and also results in the burner combustion heat not being able to be used effectively for the melting of the copper concentrates.  
           [0010]    The present invention was achieved on the basis of these circumstances and it is an object thereof to provide an facilities for feeding shredder dusts to a reverberatory furnace capable of securing the sealing of a feeding chute when shredder dusts is fed to a reverberatory furnace used for non-ferrous smelting as described above and for ensuring that the shredder dusts is burnt properly and thereby achieving an increase in the amount of this processing that can be performed.  
           [0011]    In addition, a further aim of the present invention is to provide a reverberatory furnace in which the formation of large piles the reverberatory furnace caused by unburnt of shredder dusts is prevented, and in which the blocking of the propagation of burning heat from the burner is prevented, and also in which hot gas is prevented from leaking from inside the furnace.  
         SUMMARY OF THE INVENTION  
         [0012]    In order to solve the above problems and achieve these objects, the structure described below has been employed in the present invention. Namely, the present invention relates to facilities for feeding shredder dusts to a reverberatory furnace in which shredder dusts is fed to a reverberatory furnace for non-ferrous smelting, and in particular, to facilities for feeding shredder dusts to a reverberatory furnace in which a feeding chute that passes to the inside of the reverberatory furnace is fitted to the ceiling of the reverberatory furnace and shredder dusts can be fed from this feeding chute, and which also allows oxygen enriched air to be supplied to the feeding chute and fed to the inside of the reverberatory furnace.  
           [0013]    In this case, the feeding chute is branched partway along its length and it is desirable that the shredder dusts is fed from one end thereof while the oxygen enriched air is supplied in from the other end thereof.  
           [0014]    It is also desirable that an air supply nozzle that has a smaller diameter than the feeding chute is inserted in the other end of the branched feeding pipe and the distal end of the air supply nozzle is positioned adjacent to the branched portion of the feeding chute and that the oxygen enriched air is supplied in from the air supply nozzle.  
           [0015]    Furthermore, the present invention relates to a reverberatory furnace for non-ferrous smelting provided with the shredder dust feeding facilities, and in particular, to a reverberatory furnace for non-ferrous smelting in which a burner is able to be installed in a wall portion of one end side thereof and a plurality of feeding ports to which are connected the feeding chutes of the shredder dusts feeding facilities are provided at the one end side at a ceiling portion forming a plurality of staggered rows facing another end side.  
           [0016]    In this case, it is desirable that, in the ceiling portion, the one end side where the feeding ports are provided is raised above the other end side.  
           [0017]    Moreover, it is desirable that a feeding chute of the feeding facilities is connected to each one of the plurality of feeding ports and the positions at which shredder dusts is fed to the feeding hoppers are arranged in a single row. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is a plan view showing the schematic structure of a reverberatory furnace according to the present invention.  
         [0019]    [0019]FIG. 2 is a side view as seen from the direction of the arrow A in FIG. 1 showing the schematic structure of the feeding facilities according to the present invention.  
         [0020]    [0020]FIG. 3 is a side cross sectional view showing in detail a portion of the reverberatory furnace according to the present invention.  
         [0021]    [0021]FIG. 4 is a horizontal cross sectional view of the reverberatory furnace shown in FIG. 3 (wherein below the center line O shows the cross section along the line B-B in FIG. 3).  
         [0022]    [0022]FIG. 5 is a half sectional view taken along the line C-C in FIG. 3.  
         [0023]    [0023]FIG. 6 is a plan view showing in detail a portion of the feeding facilities according to the present invention.  
         [0024]    [0024]FIG. 7 is a cross sectional view taken along the line D-D in FIG. 6.  
         [0025]    [0025]FIG. 8 is a cross sectional view taken along the line E-E in FIG. 6.  
         [0026]    [0026]FIG. 9 is a flow chart for when shredder dusts is fed to a reverberatory furnace used for smelting copper concentrates. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    [0027]FIGS. 1 through 8 show an embodiment of the present invention. In this embodiment, the present invention is applied to a green charge type (wet charge type) of reverberatory furnace  21  used for smelting copper concentrates. In the present embodiment, as is shown in FIG. 1, reverberatory furnaces  21  and  21  are provided in parallel and eight feeding ports  22  . . . are provided in each ceiling portion  21   a  of the reverberatory furnaces  21  and  21 . As is shown in FIG. 2, a shredder dusts feeding facilities  23  is provided for each of the feeding ports  22  . . . As is shown in FIG. 1 and in FIGS.  3  to  5 , as seen in plan view, the reverberatory furnaces  21  are formed in a substantially elongated schematic box shape and one end side in the longitudinal direction thereof (i.e. the bottom side in FIG. 1 and the right side in FIGS. 3 and 4) is the side where the burner is provided. A plurality of window portions  21   c  for burner installation are formed in the wall portion  21   b  of the one end side in the longitudinal direction, and two waste heat boilers  24  and  24  are connected to each reverberatory furnace  21  at the wall portion  21   d  of the other end side in the longitudinal direction (i.e. at the top side in FIG. 1 and the left side in FIGS. 3 and 4). Note that a plurality of unillustrated hoppers used for inserting copper concentrates are provided at the burner side of the ceiling portions  21   a  of the reverberatory furnaces  21  in a line along the wall portions  21   e  and  21   e  that extend in the longitudinal direction of the reverberatory furnace  21 .  
         [0028]    Approximately half of each ceiling portion  21   a  of the reverberatory furnaces  21  at the one end side in the longitudinal direction where the burner is situated is formed slightly raised above the other end side, as is shown in FIG. 3, and the above eight feeding ports  22  . . . are provided at this raised portion at the one end side. These feeding ports  22  . . . are arranged in two rows as seen in plan view in the vicinity of the center line O in the transverse direction of the reverberatory furnace  21  (i.e. in the horizontal direction in FIGS. 1 and 5 and in the vertical direction in FIG. 4) such that the same number (four) thereof are placed on either side of this center line O and in rows parallel thereto. In addition, the distance from each row of feeding ports  22 A . . . and  22 B . . . to the center line O is equal.  
         [0029]    In addition, the four feeding ports  22 A . . . and  22 B . . . in each row are arranged equidistantly in the direction of the center line O, namely, in the aforementioned longitudinal direction. Moreover, the distance between adjacent feeding ports  22  and  22  in the direction of the center line O is set equal to each other in the same row. In addition, the feeding ports of the other row are positioned at the center of adjacent feeding ports  22  and  22  in the direction of the center line of one row. Namely, the feeding ports  22 A and the feeding ports  22 B are arranged so as to alternate in a staggered (i.e. zigzag) pattern along the direction of the center line O. Note that the portion of the ceiling portion  21   a  where these feeding ports  22  . . . are provided is constructed as a water cooled copper jacket.  
         [0030]    As is shown in FIG. 2, the bottom ends of the feeding facilities  23  provided for each of the feeding ports  22  . . . arranged in this way are connected to the feeding ports  22  and open onto the inside of the reverberatory furnace  21 . In addition, the feeding facilities  23  are provided with feeding chute  25  that are provided at the ceiling portion  21   a  so as to extend vertically upwards. More specifically, as is shown in FIGS.  6  to  8 , branch pipes  26  having the same diameter as the feeding chute  25  branch out extending in a diagonally upward direction from partway along the vertically extending feeding chutes  25 . In addition, air supply nozzles  27  having a smaller diameter than the feeding chutes  25  are inserted coaxially with the feeding chutes  25  into the feeding chutes  25  from the top end thereof. Hoppers  28  are provided via a freely removable insertion damper at the top end portion of the branch pipes  26 , namely, at the position where shredder dusts is fed to the feeding chutes  25 . At the top end portion of the feeding chutes  25  into which the air supply nozzles  27  are inserted, the peripheries of the air supply nozzles  27  are sealed by lid bodies  29 . An observation window  29   a  manufactured from heat resistant glass and an inspection opening  29   b  that is normally closed are provided in each lid body  29 .  
         [0031]    Here, as is shown in FIG. 7, in the feeding facilities  23 A . . . attached to the four feeding ports  22 A . . . forming the aforementioned one row from out of the feeding facilities  23  attached to the feeding ports  22  . . . , short branch pipes  26  branch from a position in the upper end portion of the feeding chutes  25  diagonally upwards in a direction away from the center line O along a plane that intersects the center line O. In contrast, as is shown in FIG. 8, in the feeding facilities  23 B . . . attached to the feeding ports  22 B . . . forming the other row and positioned on the opposite side of the center line O from the one row of feeding ports  22 A . . . , long branch pipes  26  branch from a position in the bottom end portion of the feeding chutes  25  diagonally upwards at a sloping angle equal to that of the above branch pipes  26  of the feeding facilities  23 A along a plane that intersects the center line O. Furthermore, as seen in plan view, these branch pipes  26  extend beyond the center line O to the side of the one feeding facilities  23 A . . . (note that, for this description, in FIG. 2, the sloping angles of the branch pipes  26  in both feeding facilities  23 A and  23 B are shown as being different).  
         [0032]    By making the length and the positions where the branch pipes  26  branch from the feeding chutes  25  different, regardless of whether or not the positions of the feeding ports  22 A and  22 B in the transverse direction in the feeding facilities  23 A . . . and  23 B . . . are different, namely, regardless of whether or not the positions of the feeding chutes  25  are different, the hoppers  28  are provided on a straight line parallel with the center line O such that the positions of the hoppers  28 , namely, the positions at which the shredder dust is fed to the feeding chutes  25 , have the same height and match each other in the transverse direction, as is shown in FIG. 6. Furthermore, a shuttle conveyor  30  is provided extending parallel to the center line O directly above the hoppers  28  . . . of the feeding facilities  23 A . . . and  23 B . . . arranged thus in a straight line. As a result, when the insertion dampers are removed to the branch pipes  26 , as is shown in FIG. 1, by loading the shredder dust that has been transported via the conveyor belt  32  (corresponding to the conveyor belt  4  in FIG. 9) from the feed hopper  31  (corresponding to the feed hopper  3  in FIG. 9) into the hoppers  28  of each feed facilities  23  . . . from the shuttle conveyor  30 , it is possible to feed the shredder dust into the reverberatory furnace  21  through the feed chutes  25  via the branch pipes  26 .  
         [0033]    The bottom ends of the air supply nozzles  27  that are inserted into the feed chutes  25  through the lid portions  29  from the top end portion of the feeding chutes  25  reach as far as the branch portion of the branch pipes  26  with the feeding chutes  25 . Accordingly, in the feeding facilities  23 A in which the branch pipes  26  branch from the top end portion of the feeding chutes  25 , while the insertion depth of the air supply nozzles  27  from the top end portion of the feeding chutes  25  is shallow, in the feeding facilities  23   b  in which the branch pipes  26  branch from the bottom end portion of the feeding chutes  25 , the insertion depth of the air supply nozzles  27  is deep. In this case, the bottom ends of all of the air supply nozzles  27  are positioned substantially in the center in the vertical direction of the opening formed at the branch portion of the branch pipes  26  with the feeding chutes  25 . In contrast, the top end portion of the air supply nozzles  27  of each feeding facilities  23 A . . . and  23 B . . . are bent in a horizontal direction at the point where they protrude from the lid bodies  29  and are then connected with larger diameter air supply pipes  33 . Each air supply pipe  33  is connected to an unillustrated oxygen enriched air supply source such as, for example, the oxygen plant  5  shown in FIG. 9. Oxygen enriched air having a predetermined density and pressure is expelled from the air supply nozzles via the air supply pipes  33  and is able to be supplied into the reverberatory furnace  21  together with shredder dust fed through the branch pipes  26 . Note that an operation floor  34  is placed at a distance above the ceiling portion  21   a  of the reverberatory furnace  21 . In the present embodiment, the operation floor  34  is provided with a water cooled plate to insulate it from the heat from the reverberatory furnace  21  and the top end portions of the feeding chutes  25  and the branch pipes  26  protrude above this operation floor  34 .  
         [0034]    In the facilities  23  for feeding shredder dusts to the reverberatory furnace  21  having the structure described above, in order to feed shredder dust that is inserted via the branch pipes  26  from the feeding chutes installed via the feeding ports  22  in the ceiling portion  21   a  of the reverberatory furnace  21  together with oxygen enriched air supplied in through the air supply nozzles  27  to the reverberatory furnace  21 , the shredder dusts is inserted into the reverberatory furnace  21  while being burnt by the oxygen enriched air that is supplied together with it. Accordingly, even if the atmosphere inside the reverberatory furnace  21  becomes insufficient in oxygen, it is possible to ensure that the fed shredder dust is incinerated at a high temperature. The result of this is that shredder dust from scrapped automobiles and the like can be reliably processed without generating harmful materials such as dioxin, and also that the heat from the combustion can be used effectively for the smelting of (for example copper concentrates). Moreover, it is possible to suppress the actual formation of the aforementioned piles caused by unburnt shredder dust.  
         [0035]    In addition, by feeding shredder dust together with oxygen enriched air to the inside of the reverberatory furnace  21  in this way, the feeding chutes  25  and the feeding ports  22  in the ceiling  21   a  of the reverberatory furnace  21  to which the shredder dusts is fed can be sealed by the pressure of the supplying of the oxygen enriched air. Accordingly, even if the furnace pressure inside the reverberatory furnace  21  changes and a sufficient negative pressure state cannot be maintained inside the reverberatory furnace  21 , it is possible to prevent the high temperature gas inside the reverberatory furnace  21  from leaking from the feeding ports  22  through the feeding chutes  25 . As a result, without providing a double damper as in a conventional chute pipe, for example, it is possible to prevent a state in which the conveyor belt of the shuttle conveyor  30  is burned from occurring, and a continuous feed of the shredder dusts becomes possible. Namely, according to the feeding facilities  23  having the above described structure, the sealing performance is secured and it is possible to reliably burn the shredder dusts and stable, efficient processing of shredder dust can be promoted.  
         [0036]    It should be noted that if oxygen enriched air and shredder dusts are fed in this way via the feeding chutes  25  to the interior of the reverberatory furnace  21 , it is also possible to consider, for example, a means in which the branch pipes  26  as they are in the present embodiment are not provided, and shredder dusts is fed to a single feed pipe and is then pressure supplied by oxygen enriched air. However, in a means such as this, the risk of the shredder dusts becoming blocked inside this single feed pipe and the supply of the oxygen enriched air being obstructed and the oxygen enriched air then damaging the sealing performance described above must be considered. In contrast to this, in the feeding facilities  23  of the present embodiment, the branch pipes  26  are provided branching off from partway along the feeding chutes  25  and shredder dusts is fed from these branch pipes  26  while oxygen enriched air is supplied from the top end portion of the feeding chutes  25 . Accordingly, even if the shredder dusts becomes blocked inside the branch pipes  26 , the supply of the oxygen enriched air is not cut off and, at the least, the sealing performance can be ensured due to the oxygen enriched air and it is possible to reliably prevent high temperature gas from leaking from inside the reverberatory furnace  21 .  
         [0037]    Furthermore, in the feeding facilities  23  of the present embodiment, when oxygen enriched air is supplied from the top end portion of the feeding chutes  25 , the small diameter air supply nozzles  27  are inserted into the feeding chutes  25  and the distal end (i.e. the bottom end) thereof is positioned at the connecting portion of the branch pipes  26  with the feeding chutes  25 , and oxygen enriched air is supplied from the air supply nozzles  27  at a predetermined pressure into the feeding chutes  25  and fed into the reverberatory furnace  21 . Accordingly, because the portions inside the branch pipes  26  where they connect to the feeding chutes  25  are placed in a negative pressure condition by the oxygen enriched air supplied in via the air supply nozzles  27 , the shredder dusts inserted into the branch pipes  26  from the hoppers  28  is fed by being sucked into the feeding chutes  25 . As a result, it is possible to prevent the shredder dusts from becoming blocked and to achieve a reliable and smooth feed of shredder dusts.  
         [0038]    In addition, in the reverberatory furnace  21  of the present embodiment, in the ceiling portion  21   a,  the plurality of feeding ports  22  in which the above feeding facilities  23  are provided are placed in a staggered arrangement running from the wall portion  21   b  of the reverberatory furnace  21  in which the burners are placed in the longitudinal direction of the reverberatory furnace  21 , namely, in the direction of the burning by the burners. As a result, it is possible to prevent the formation of the above described large piles inside the reverberatory furnace  21  and to prevent flames from escaping out from the feeding ports  22  . . . and the burning of the burner being obstructed. Namely, by placing the feeding ports  22  . . . in a staggered arrangement, the distance between each of the feeding ports  22  and  22  is increased compared with if, for example, they were placed in a lattice arrangement. Therefore, even if the piles are formed, they can be prevented from becoming too large. The result of this is that, as described above, the gap to the ceiling  21   a  is maintained and flames are prevented from escaping. In addition, it is possible to spread the burning of the burner over the whole interior of the reverberatory furnace  21  (i.e. as far as the other side) and to melt the copper concentrates, and also to effectively use the heat of the burning of the fed shredder dust.  
         [0039]    Furthermore, in the reverberatory furnace  21  of the present embodiment, the portion at one end side of the ceiling portion  21   a  in the longitudinal direction of the reverberatory furnace  21  where the burner is situated is formed slightly raised above the other end side, and the feeding ports  22  . . . are provided in a staggered arrangement in this raised portion. Accordingly, even if the above described piles do become formed, it is possible to ensure that a sufficient clearance is maintained between the piles and the ceiling portion  21   a , therefore, it is possible to even more reliably prevent flames from leaking.  
         [0040]    It should be noted that when the feeding ports  22  . . . are arranged in two rows in a staggered arrangement in this manner, if the feeding chutes  25  . . . of the feeding facilities  23  . . . connected to the feeding ports  22  . . . are only provided in the ceiling portion  21   a  extending vertically, then the feed positions where shredder dusts is fed to these feeding pipes  25  . . . , namely, the positions of the hoppers  28  . . . also end up being arranged in two staggered rows. Accordingly, in order to insert the shredder dusts into this type of hopper  28  . . . , it is necessary to provide two rows of shuttle conveyors for transporting the shredder dusts from the conveyor belt  32  to a single reverberatory furnace  21 .  
         [0041]    In contrast, in the case of the reverberatory furnace  21  of the present embodiment, in the feeding facilities  23 A . . . attached to the feeding ports  22 A . . . forming the one row parallel to the center line O in the reverberatory furnace  21  from out of the feeding ports  22  . . . arranged in a staggered pattern, short branch pipes  26  branch from a position in the upper end portion of the feeding pipes  25  while, in the feeding facilities  23 B . . . attached to the feeding ports  22 B . . . forming the other row, long branch pipes  26  branch from a position in the bottom end portion of the feeding chutes  25  parallel to the branch pipes  26  of the feeding facilities  23 A. Furthermore, the top end positions of the branch pipes  26  . . . to which the shredder dusts is fed match each other in height and in their positions in the transverse direction and a single row of the hoppers  28  . . . is provided at the top end thereof. Accordingly, in this reverberatory furnace  21 , there only needs to be a single row of the shuttle conveyor  30  for feeding the shredder dust from the hoppers  28  . . . to the feed chutes  25  . . . of each of the feed facilities  23 A . . . and  23 B . . . via the branch pipes  26  . . . As a result, even if there are a plurality of rows of the feeding ports  22  . . . arranged in a staggered pattern, there does not need to be a plurality of rows of shuttle conveyors  30 , which is economical as well as efficient.  
         [0042]    Note that, in this reverberatory furnace  21 , the feeding ports  22  . . . are arranged in two rows in a staggered pattern, however, it is also possible for the feeding ports  22  . . . to be arranged in three or more rows in the above staggered pattern depending on the size and the like of the reverberatory furnace  21 . Moreover, in each row of the feeding facilities  23 A . . . and  23 B . . . , instead of forming the branch pipes  26  all at an equal slope angle branching out from different positions of the feeding chutes  25 , as described above, it is possible, as is shown in FIG. 2, to provide branch pipes  26  having different slope angles and to make both the branch position and the slope angle different. In these examples, in the same way as in the present embodiment, it is also possible to make the positions (the positions of the hoppers  28  . . . in the present embodiment) from which the shredder dusts is fed to the feed chutes  25  . . . in one row.