JPH1136021A - Metal recovering apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal recovering apparatus capable of efficiently crushing residual sag and electric balls and efficiently and rapidly separating the residual slag and molten metal. SOLUTION: This apparatus has a rotating furnace 2 which is housed in a housing 3 freely rotatably disposed in a supporting base 4, a rotary driving mechanism which rotates this rotating furnace 2 at a high speed, an agitating vane member 14 which is inserted along the central axis of the rotating furnace 2 and plural pieces of agitating balls 13 which are fed into the furnace. This rotary driving mechanism has a driving motor 10, an engaging shaft 11a formed in the output part of this driving motor 10 and an engaging hole 12a projectingly disposed in the central part at the bottom of the rotating furnace 2. The engaging hole 12a and the engaging shaft 11a are so constituted as to be tightly fitted relatively nonrotatably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal recovery apparatus and a metal recovery method. More specifically, the present invention relates to a method for efficiently recovering aluminum from scraps of metal products, particularly aluminum cans, aluminum sashes, and the like containing aluminum as a main material, and an apparatus suitably used in this method.

[0002]

2. Description of the Related Art Conventionally, the operation of recovering metal from scrap metal such as aluminum has been performed in two stages.

That is, in the first stage, metal scrap is put into a furnace, and the scrap is melted by heating with a burner or the like while rotating the furnace body in a tilted state. Then, the furnace is turned over to take out the molten metal. Residues (also referred to as residual ash, slag, etc.) remain in the furnace, but the residuals still contain a large amount of metal.

[0004] In the second step, the residue left in the furnace is transferred to the furnace or the residue is transferred to another furnace, and a heating agent is charged into the furnace. By rotating, the metal content contained in the residue is melted. Then, the furnace is turned over to take out the molten metal. This second stage of work is also referred to as ashing within the industry.

A furnace for ashing (hereinafter referred to as an ashing machine) provided separately from the furnace for melting the scrap is disclosed in, for example, JP-A-50-141507 and Japanese Utility Model Publication No. 60-32110. What was done is known. In this method, the residue placed in a furnace for ash extraction is heated, and a stirring blade installed in the furnace is rotated to separate molten metal from the residue.

[0006] Also, a method is known in which a plurality of massive refractory stirring balls are charged into a furnace without using a stirring blade, and the furnace is rotated to stir the residue in the furnace.
No. 6,086,045. This is to separate the residue and the molten metal by centrifugal force, and to crush the residue and the metal ball by thermite reaction by the stirring ball.
The rotation mechanism engages a pinion with a rack engraved around the furnace, and rotates the pinion by a motor.

Further, Japanese Utility Model Laid-Open No. 6-56694 discloses a sprocket formed around the bottom of the furnace, an endless chain is engaged with the sprocket, and the endless chain is rotated by a motor. I have.

[0008]

However, in the case of using a rotary stirring blade, a mechanism for vertically moving the stirring blade above the furnace is required. This is because the stirring blade is inserted into the furnace only at the time of stirring, and the stirring blade is retracted upward at the time of adding the residue and removing the molten metal. Further, a mechanism for rotating the stirring blade is required. Further, in the case of aluminum which usually accounts for about 60 to 65% by weight of the first ash, the metal recovery rate in the first ash is about 50 to 60% of the contained aluminum. Requires a long working time. Further, the stirring blade may be damaged.

On the other hand, in the case of a rotary furnace system not using a stirring blade, the furnace is rotated by using a rack and pinion or an endless chain, so that the rotation speed is as low as about 15 rpm at the maximum. Therefore, the centrifugal separation effect is not as expected, and as a result, the metal recovery rate of the first ash is 5%.
It is only about 0%.

[0010] The present invention has been made to solve the above-mentioned problem, and the centrifugal separation effect is improved by providing a mechanism capable of rotating the furnace at a high speed. Further, by inserting a stirring blade at the center of the furnace. An object of the present invention is to provide a metal recovery device having an improved stirring effect.

It is another object of the present invention to provide a metal recovery apparatus in which the centrifugal separation effect is improved by providing a mechanism capable of rotating the furnace at high speed, and the centrifugal separation effect and the stirring effect are improved by employing a stirring ball.

The present invention also provides a method for recovering metal using the above apparatus.

As a result, the metal recovery rate can be greatly improved.

[0014]

According to a first aspect of the present invention, there is provided a metal recovery apparatus comprising: a rotary furnace rotatably disposed on a machine frame; a rotary drive mechanism for rotating the rotary furnace at a high speed; A stirring blade member that can be charged along the central axis of the furnace.

Accordingly, in the furnace, the residue and the molten metal are effectively separated in a short time by the high-speed rotation of the furnace (which can be rotated up to about 120 rpm). Also, in this case,
Since the stirring blade member stirs the residue generally collected in the central portion in the furnace due to the difference in mass, the separation effect is further improved. In addition, the high-speed rotation means about 120 rpm.

The rotation drive mechanism includes a drive motor and a connection mechanism for connecting an output section of the drive motor to the center of the rotary furnace bottom. The connection mechanism includes an output section of the drive motor. And an engagement hole formed in one of the rotary furnace bottom center portion, and an engagement shaft formed in the other, so that the engagement hole and the engagement shaft cannot be relatively rotated. In a metal recovery device that can be fitted tightly, it is possible to rotate the furnace by a direct drive method, so that it is possible to rotate the furnace at high speed that could not be realized by the conventional rack pinion method or endless chain method . Further, a mechanism such as a rack or a chain is not required, and maintenance is facilitated. In addition, the structure is extremely simple, the separation of the rotary furnace and the rotating mechanism is easy, and the degree of freedom of design is improved because the engagement hole and the engagement shaft can be changed and set according to the size of the rotary furnace.

Another metal recovery apparatus of the present invention comprises a rotary furnace rotatably disposed on a machine frame, a rotary drive mechanism for rotating the rotary furnace, and a plurality of stirring balls put into the furnace. Wherein the rotation drive mechanism includes a drive motor, an engagement hole formed in one of an output portion of the drive motor and a central portion of the rotary furnace bottom, and an engagement shaft formed in the other. And the engagement hole and the engagement shaft can be closely fitted so that they cannot rotate relative to each other.

Therefore, the rotary furnace can be rotated at a high speed, and the effect of separating the residue and the molten metal is improved. further,
The plurality of stirring balls improve the effect of crushing the residue when the rotary furnace is rotated and crushing the electric ball by thermite reaction, and as a result, the separation efficiency between the residue and the molten metal is further improved.

Further, in the above-mentioned metal recovery apparatus, a blade shaft disposed on the machine frame so as to be able to advance and retreat along the central axis of the rotary furnace, and is fixed substantially radially around the blade shaft. In the apparatus provided with the stirring blade member having a plurality of short stirring blades, the introduction of the residue and the removal of the molten metal by the tilt furnace (tilting the rotary furnace about a substantially horizontal axis) are performed. It is preferable because it becomes easy. In addition, since the stirring blade is short, the residue at the center of the furnace is stirred, and interference between the stirring ball and the stirring blade is prevented, which is preferable.

[0020] The metal recovery apparatus according to the second aspect of the present invention comprises:
A rotary furnace rotatably disposed on a machine frame, a stirring blade member that can be inserted along a central axis of the rotary furnace, and a rotating direction of the rotary furnace while rotating the rotary furnace. And a rotating drive mechanism for rotating the bevel gear in a direction opposite to the direction in which the bevel gears coaxially oppose each other, and a bevel gear for driving meshing with the pair of bevel gears from the lateral direction. The rotation of the drive bevel gear causes the pair of bevel gears to rotate in opposite directions, so that the rotary furnace and the stirring blade member rotate in opposite directions.

Therefore, since the rotary furnace and the stirring blade member rotate in the opposite directions by a simple mechanism, the relative rotation between the two becomes high even if they are not rotated at a very high speed, so that the stirring effect is improved. Further, since the residue is prevented from rotating together with the stirring blade member, the stirring effect is improved.

In this metal recovery apparatus, the stirring blade member includes a blade shaft arranged to be able to advance and retreat along the central axis of the rotary furnace, and a plurality of blades fixed substantially radially around the blade shaft. The stirring blade having the annular frame shape is preferable in that the stirring effect is further improved. Note that the annular frame shape is not particularly limited to a circular shape or a semicircular shape, but also means a shape including a rectangular shape along the inner peripheral surface of the rotary furnace. Therefore, if the annular frame-shaped outer portion of the stirring blade is formed along the inner surface of the rotary furnace, an action of scraping off the residue adhered and retained on the inner surface of the rotary furnace is generated, and the stirring effect is improved.

Further, in the above-described metal recovery apparatus, in the case where the machine frame is configured to be tiltable about a substantially horizontal axis, the tilt furnace is enabled.

According to the metal recovery method of the present invention, a plurality of churning stirring balls made of a refractory are charged into a rotatable rotary furnace, and fixed stirring blade members are charged into the rotary furnace along a central axis thereof. Then, by rotating the rotary furnace at a high speed, the residue containing the molten metal in the furnace is stirred, and thereafter, a desired metal is recovered.

Therefore, the function and effect of the above-described metal recovery device are exhibited.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a metal recovery apparatus according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a partially sectional front view showing an embodiment of the metal recovery apparatus of the present invention, FIG. 2 is a plan view of the metal recovery apparatus of FIG. 1, and FIG. 3 shows the tilting operation of the metal recovery apparatus of FIG. FIG. 4 is a schematic perspective view of the metal recovery apparatus of FIG. 1, FIG. 5 is a front sectional view showing another embodiment of the metal recovery apparatus of the present invention,
6 is a front sectional view showing still another embodiment of the metal recovery apparatus of the present invention, FIG. 7 is an enlarged view of a portion VII in FIG. 6, and FIG. 8 is a main part of still another embodiment of the metal recovery apparatus of the present invention. FIG.

As shown in FIGS. 1 to 4, the metal recovery apparatus 1 of this embodiment has a hemispherical (so-called bowl-shaped) rotary furnace 2.
Are housed in a rectangular housing 3, and the housing 3 is rotatably supported by a pair of support bases 4. This support 4 is one form of a machine frame referred to in the claims. And, the tilting furnace motor 5 installed on one support base 4
Thus, the rotary furnace 2 can be rotated around its horizontal support shaft 6 (see FIG. 3).

The housing 3 is formed of a steel plate or the like, and has reinforcing ribs 3a made of so-called channel steel, angle steel, or the like.
Is fixed. A door 7 that opens upward is attached to an upper end surface of the housing 3 by a hinge 8. This door 7
Is opened, the residue is put into the rotary furnace 2 from above, and the door 7 is opened.
The housing 3 is tilted in a state where is opened to take out the molten metal. In addition, 9 is a chimney.

The rotary furnace 2 is made of cast iron or cast steel, but the material is not particularly limited as long as it has necessary heat resistance and strength. The rotary furnace 2 is rotated by a drive motor 10 disposed below the rotary furnace. The rotation speed of the drive motor 10 can be controlled by, for example, inverter control or the like. In the present embodiment, since the drive motor 10 is installed horizontally, it is connected to the center of the bottom of the rotary furnace 2 via a pair of bevel gears (hereinafter, bevel gear mechanism) 11. The output portion of the bevel gear mechanism 11 is an engagement shaft 1 having a hexagonal cross section.
1a. On the other hand, in the center of the bottom of the rotary furnace 2, an engagement hole 12 having a hexagonal cross section to which the engagement shaft 11a can be tightly fitted.
A boss 12 having a is protruded. Such an engagement shaft 1
The rotation of the drive motor 10 is transmitted to the rotary furnace by the 1a and the engagement hole 12a. The engagement shaft 11a may be protruded from the bottom of the rotary furnace 2 and the boss 12 may be formed on the bevel gear mechanism 11. Further, the engaging shaft 11a and the engaging hole 12a are not particularly limited to a hexagonal section, but may be a polygonal section such as a square. A well-known key may be used after having a circular cross section. In short, what is necessary is just to make the relative rotation between the rotary furnace and the drive motor output unit impossible.

In this embodiment, a bevel gear mechanism is used as the transmission mechanism. However, when the drive motor 10 is installed vertically, a spur gear mechanism or the like may be used, or the motor shaft may be directly connected to the rotary furnace 2. Good.

As described above, since the motor is rotated by a direct drive without using an endless chain or rack, high-speed rotation is possible, and the efficiency of separating the residue and the molten metal is improved. Further, if the rotary furnace 2 is lifted upward by a forklift, a crane, or the like, the rotary furnace 2 can be easily separated from the bevel gear mechanism. As described above, the metal recovery apparatus 1 of the present embodiment normally puts the residue into the rotary furnace 2 and takes out the molten metal in a state of being housed in the housing 3.
If an engaging flange or the like is formed on the upper edge of the rotary furnace, the rotary furnace 2 can be moved to a desired place by a forklift, a crane, or the like. Therefore, it is also possible to input the residue and take out the molten metal at another place. In this case, the door 7 is not shown in the drawing, but has a size that can form an opening through which the rotary furnace 2 can enter and exit.

At the start of the ashing operation, a plurality of stirring balls 13
Into the residue in the rotary furnace 2. The stirring ball 13 is formed of cast iron or the like, and is generally spherical with a diameter of about 5 cm, but the shape is not particularly limited. By introducing the stirring balls 13, the effect of stirring and crushing the residue when the rotary furnace is rotated is improved. Also,
For example, aluminum may cause a thermite reaction at a high temperature to form a lump containing molten aluminum (this may be referred to as an electric ball in the art). This makes it easier to take out the molten aluminum. Therefore,
The separation efficiency between the residue and the molten metal, which is improved by the high-speed rotation, is further improved.

As shown in FIGS. 1 and 4, a stirring blade member 14 is inserted from above along the central axis of the rotary furnace 2. The stirring blade member 14 in this embodiment is made of cast iron, and short stirring blades 16 are formed radially around the blade shaft 15. The length of the stirring blade 16 is set to the rotary furnace 2 of the present embodiment.
The upper wings are longer and the lower wings are shorter to accommodate the inner shape of the wing. Therefore, if the rotary furnace has, for example, a vertically long cylindrical shape, it is preferable that the stirring blades 16 have the same length from the upper part to the lower part of the blade axis. In addition, stirring blade 1
The reason for shortening the length 6 is to avoid contact with the stirring balls 13 that move upward along the inner peripheral surface of the rotary furnace 2 due to the rotation of the rotary furnace 2. Further, the stirring blade member 14 plays the role of stirring and crushing the residue in the central portion where the stirring and crushing is not promoted by the stirring ball 13 as compared with the vicinity of the inner wall of the rotary furnace 2. Although the stirring blade member 14 is fixed without rotating, the residue in the furnace rotates, so that the residue is relatively stirred. The stirring blade member 14 further improves the metal recovery rate. Of course, a known rotating mechanism may be provided to rotate the stirring blade member 14 around its blade axis 15. In that case, rotation in the same direction as the rotation direction of the rotary furnace 2 may be performed, or rotation in the opposite direction may be performed. Further, the rotation speed may be automatically changed according to the rotation speed of the rotary furnace 2.

Regarding the distance between both ends of the stirring blade, for example,
In the case of the illustrated rotary furnace 2, since the inner diameter is 1140 mm, the distance between both ends of the uppermost stirring blade 16 is set to about 150 mm. This distance may be changed according to the number of the stirring balls 13, the maximum number of rotations of the rotary furnace 2, and the like. Also, in this case,
The diameter of the blade shaft 15 is about 60 mm.

As shown in FIG. 1, the stirring blade member 14 is configured to be moved up and down so as to be charged into the rotary furnace 2 and withdrawn upward. A well-known mechanism may be used for the mechanism for moving up and down. In the present embodiment, a beam 17 fixed to the upper end of the stirring blade member 14, a pair of rack members 18 erected on both support bases 4, and a pair of upper and lower And a drive motor 20. The two vertical drive motors 20 are arranged on the beam 17 and are operated synchronously with each other. 20a is a casing of the motor 20. However, in the present invention, it is not limited to the rack and pinion, for example, a screw rod is erected instead of the rack member,
Instead of the pinion, an inner screw ring whose axial movement is prohibited may be provided, and the beam 17 may be moved up and down by rotating the inner screw ring by a motor or the like. Further, it may be driven by a chain.

A stopper (not shown) is provided on the support 4, the housing 3, or the beam 17, and when the beam 17 is lowered together with the stirring blade member 14 to a predetermined position, the stopper is manually or automatically operated by the stopper. Beam 17
Are fixed to the support 4 or the housing 3.

A heat insulating plate 21 is provided in the housing 3 between the rotary furnace 2, the drive motor 10 and the bevel gear mechanism 11, so that the drive motor 10 and the like are protected from the heat of the rotary furnace 2 at high temperature. ing. This heat insulating plate 21 is formed of, for example, asbestos.

According to the present metal recovery apparatus 1, it is possible to recover almost 90% or more of the metal contained in the first ash by one operation. Further, the processing time is about 5 minutes, which is significantly shorter than that of the conventional apparatus.

In the above embodiment, the short stirring blades 16 were employed in order to put the stirring balls 13 into the furnace. However, the present invention is not limited to this. For example, the metal recovery device shown in FIG. Like FIG. 22, a stirring blade member 24 having a long stirring blade 23 may be provided without using the stirring ball 13. In the case of the illustrated metal recovery device 22, the distance between both ends of the longest one (the uppermost blade) of the stirring blades 23 is set to be ２ of the inner diameter of the rotary furnace 2. Specifically, the rotary furnace 2
Is 1140 mm, and the distance between both ends of the stirring blade 23 is 760 mm.

In this case, the door 7 is disposed on both sides of the beam 17 so that an opening having a size through which the stirring blade member 24 can pass can be formed. Therefore, the door is opened when the stirring blade member 24 moves up and down.

FIG. 6 shows another embodiment. The metal recovery device 25 includes a rotary furnace 26 and a stirring blade member 27.
Rotate in opposite directions about the same axis.

The rotation drive mechanism includes a pair of bevel gears 28,
The drive-side bevel gear 30 meshes with both of the pair of bevel gears 28 and 29 from the lateral direction. The drive-side bevel gear 30 is rotated by a drive motor 34 via a pulley 31, an endless belt 32, and a reduction gear mechanism 33, whereby the pair of bevel gears 28 and 29 rotate in opposite directions.

The shaft 28a of the upper bevel gear 28 of the pair of bevel gears is detachably connected to the blade shaft 35 of the stirring blade member 27 by a known connecting pin 35a.
The shaft 29a of the lower bevel gear 29 is detachably connected to a support beam 36 fixed to the rotary furnace 26 by a known mounting bolt 37.

As shown, the shaft 28a of the upper bevel gear 28 and the shaft 29a of the lower bevel gear 29 have a double structure without interfering with each other. In this embodiment, the shaft 29a penetrates the inside of the shaft 29a.

The bevel gears 28 and 29 are prevented from approaching or separating from each other by a spacer or the like (not shown).

The stirring blade member 27 is composed of the blade shaft 35 and a plurality of annular frame-shaped stirring blades 38 projecting radially around the blade shaft 35. The inner circumferential side portion of the stirring blade 38 is formed along the inner circumference of the rotary furnace. As shown in the figure, adjacent stirring blades 38 are arranged so as to be shifted in the blade axis direction. This is because the stirring effect is improved. Note that the number of stirring blades is not limited to two in the figure, and may be three or more.

In the present metal recovery apparatus 25, the molten metal pouring port 39 is perforated at the bottom of the rotary furnace 26. During the operation of the metal recovery device 25, the blade shaft 3 of the stirring blade member 27 is
5 is inserted so that the molten metal does not flow out. When the molten metal is poured, the stirring blade member 27 is raised together with the blade shaft 35 by the elevating mechanism 40 so that the spout 3
9 is opened.

The details of the spout 39 are shown in FIG.
A conical hole is drilled in the bottom of the rotary furnace 26, and a liner member 41 having a conical outer shape and having a cylindrical hole 41a drilled therein is detachably (replaceably) screwed. A small diameter portion 35b at the lower end of the blade shaft 35 is fitted into the cylindrical hole 41a. The blade shaft 3 is provided on the upper end surface of the liner member 41.
Since the step 35c of No. 5 is pressed by gravity, sealing against the molten metal is performed. Reference numeral 42 denotes a thrust member that rotatably supports the center of the bottom of the rotary furnace 26 and is attached to the housing 3.

The elevating mechanism 40 is constituted by rack teeth 28b formed around a shaft 28a of the upper bevel gear 28 and a pinion 43a fixed to the operation handle shaft 43. Thereby, the shaft 2 of the upper bevel gear 28
The stirring blade member 27 is moved up and down together with 8a.

In FIG. 6, reference numeral 44 denotes a bucket for charging the residue into the rotary furnace 26, and reference numeral 45 denotes a gear cover.

When discharging the residue after the molten metal has been poured out, the metal recovery apparatus 1 (FIGS. 1-4), 22
As in (FIG. 5), the rotary furnace 26 is tilted by the tilt furnace motor 5.

It is preferable to use a well-known continuously variable motor for the drive motors 10 and 34.

FIG. 8 shows another example of the bevel gear mechanism of the metal recovery device 25 shown in FIG. That is, this is a bevel gear mechanism that changes the rotation speed of the stirring blade member 27 and the rotation speed of the rotary furnace 26. The drive-side bevel gear has a multi-tooth gear 30 and a minor-tooth gear 30a coaxially mounted thereon, and bevel gears 28 and 29b having different numbers of teeth mesh with the respective gears 30 and 30a. In the present embodiment, the rotation speed of the stirring blade member 27 is set to ４ of the rotation speed of the rotary furnace 26. This ratio is not particularly limited.

[0055]

According to the present invention, the residue and the molten metal are effectively separated in a short time by the high-speed rotation of the furnace.
In this case, since the stirring blade member stirs the residue that generally collects in the central portion of the furnace due to the mass difference, the separation effect is further improved.

Further, according to the present invention, the effect of separating the residue and the molten metal is improved, and the residue is crushed when the rotary furnace is rotated by a plurality of stirring balls, and the electric ball is formed by thermite reaction. The effect of crushing is improved, and as a result, the separation efficiency between the residue and the molten metal is further improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view showing an embodiment of a metal recovery device of the present invention.

FIG. 2 is a plan view of the metal recovery device of FIG.

FIG. 3 is a side view showing a tilting operation of the metal recovery device of FIG. 1;

FIG. 4 is a schematic perspective view of the metal recovery device of FIG.

FIG. 5 is a front sectional view showing another embodiment of the metal recovery device of the present invention.

FIG. 6 is a front sectional view showing still another embodiment of the metal recovery apparatus of the present invention.

FIG. 7 is an enlarged view of a portion VII in FIG. 6;

FIG. 8 is a partial cross-sectional front view showing a main part of still another embodiment of the metal recovery apparatus of the present invention.

[Explanation of symbols]

 1, 22, 25 ··· Metal recovery device 2, 26 ··· Rotary furnace 3 ··· Housing 4 ··· Support base 5 ··· Tilt furnace motor 7 ··· Door 9 ··· Chimney 10, 34 ··· Drive motor 11 ··· Bevel gear mechanism 11a ··· Engaging shaft 12 ··· Boss 12a ··· Engaging hole 13 ··· Stirring ball 14 24, 27 ... stirring blade member 15, 35 ... blade axis 16, 23, 38 ... stirring blade 17 ... beam 18 ... rack member 19 ... pinion 20 ··· Vertical drive motor 21 ··· Insulating plates 28, 29 ··· Bevel gear 30 ··· Drive side bevel gear 31 ··· Pulley 32 ··· Endless belt 33 ··· Reduction gear mechanism 36 Support beam 37 Mounting bolt 39 Spout 40 Elevating mechanism 41 Liner member 42 ... the thrust member

Claims (8)

[Claims] A rotary furnace rotatably disposed on a machine frame;
A metal recovery apparatus comprising: a rotary drive mechanism for rotating the rotary furnace at a high speed; and a stirring blade member that can be inserted along a central axis of the rotary furnace. 2. The rotary drive mechanism includes a drive motor and a connection mechanism for connecting an output of the drive motor to the center of the rotary furnace bottom, wherein the connection mechanism includes an output of the drive motor. And an engagement hole formed in one of the center part of the rotary furnace bottom and an engagement shaft formed in the other, and the engagement hole and the engagement shaft are relatively unable to rotate. The metal recovery device according to claim 1, wherein the metal recovery device is configured to be able to be closely fitted. 3. A rotary furnace rotatably disposed on a machine frame,
A rotary drive mechanism for rotating the rotary furnace; and a plurality of stirring balls to be put into the furnace. The rotary drive mechanism includes a drive motor, an output section of the drive motor, and a central portion of the rotary furnace bottom. And an engaging shaft formed in the other, so that the engaging hole and the engaging shaft can be tightly fitted to each other so that they cannot rotate relative to each other. Metal recovery device configured as follows. 4. A blade shaft disposed on the machine frame so as to be able to advance and retreat along a central axis of a rotary furnace, and a plurality of short stirring blades fixed substantially radially around the blade shaft. The metal recovery device according to any one of claims 1 to 3, further comprising a stirring blade member having: 5. A rotary furnace rotatably disposed on a machine frame,
A stirring blade member that can be inserted along the central axis of the rotary furnace, and a rotation drive mechanism that rotates the rotary furnace and rotates the stirring blade member in a direction opposite to the rotation direction of the rotary furnace. The rotation drive mechanism includes a pair of bevel gears coaxially opposed to each other, and a drive bevel gear meshing with the pair of bevel gears from the lateral direction. A metal recovery device configured such that the rotary furnace and the stirring blade member rotate in opposite directions by rotating the pair of bevel gears in opposite directions. 6. A blade shaft in which the stirring blade member is provided so as to be able to advance and retreat along a central axis of a rotary furnace, and a plurality of annular frames fixed substantially radially around the blade shaft. The metal recovery apparatus according to claim 5, further comprising a stirring blade having a shape. 7. The metal recovery apparatus according to claim 1, wherein the machine frame is configured to be tiltable about a substantially horizontal axis. 8. A plurality of churning stirring balls made of a refractory are put into a rotatable rotary furnace, and fixed stirring blade members are charged into the rotary furnace along a central axis thereof. A metal recovery method in which a residue containing a molten metal in a furnace is stirred by rotating at a high speed, and then a desired metal is recovered.