JPWO2008153001A1 - Metal recovery device - Google Patents

Abstract

As a device used for recovering metals from metal-containing solutions by electrolysis, a metal that can save space and reduce equipment load compared to conventional recovery devices, and can recover metals in a short time An apparatus with extremely excellent recovery efficiency is provided. The apparatus includes a columnar or cylindrical rotating cathode that rotates about an axis, an anode disposed so as to face the rotating cathode, and a net-like or porous conductor, and faces the anode. What is necessary is just to comprise at least one part of the surface of the said rotating cathode covered with the said conductor. In addition, the apparatus includes a columnar or cylindrical rotating cathode that rotates about an axis, and an anode disposed to face the rotating cathode, and at least a surface of the rotating cathode facing the anode A part may be processed by uneven processing.

Description

  The present invention relates to a metal recovery apparatus that recovers metal from a solution containing metal by electrolysis.

  Some waste liquids (for example, treatment liquids) discharged from factories contain metals such as Au, Ag, Cu, and platinum group elements. These metals are recovered from the waste liquid and recycled. Used. An electrolysis method is known as a method for recovering metal from waste liquid.

  As a metal recovery device using an electrolysis method, for example, in Patent Document 1, a cylindrical inner electrode is provided as a cathode, and an outer electrode is provided around the inner electrode as an anode, and the cathode is configured to be rotatable. In the vicinity of the surface of the cathode on which the metal is deposited, there has been proposed a collection device provided with a plastic collection plate in contact with or close to the metal deposited on the surface of the cathode. According to the method of Patent Document 1, it is described that metal deposited on the cathode surface is scraped off using a plastic recovery plate and deposited below the cathode without being attached to the electrode, and then the metal can be recovered.

  By the way, in order to recover metals from waste liquid industrially, it is desired to increase the recovery efficiency so that the metals can be recovered in as short a time as possible. However, the recovery apparatus disclosed in Patent Document 1 has a poor metal recovery efficiency and takes a long time to recover the metal. Moreover, in the said patent document 1, since the metal electrodeposited on the cathode surface was scraped off using a plastic recovery plate, and the metal was deposited under the cathode and collect | recovered, the collection | recovery apparatus was not able to save space. . Further, depending on the type of waste liquid, the metal deposited under the cathode may be redissolved in the waste liquid, and the metal cannot be sufficiently recovered from the waste liquid.

  As a method for improving the metal recovery efficiency, for example, Patent Document 2 and Patent Document 3 propose a method using a cathode disk.

  Patent Document 2 describes that electrolysis is performed while rotating a disk-shaped cathode, thereby improving the contact efficiency between the cathode and the electrolyte and improving the metal recovery efficiency. In addition, in Patent Document 3, in order to improve the metal recovery efficiency by efficiently stirring the solution in the electrolytic cell, an aspect including a rotation drive mechanism that rotates either the anode or the cathode, A mode in which stirring blades are provided on the anode or the cathode is described.

  However, when the cathode disk is used as in Patent Document 2, it is necessary to excessively increase the number of rotations of the cathode in order to increase the metal recovery efficiency, and there is a problem that the equipment load increases.

  On the other hand, although it is not a technique proposed to increase the metal recovery efficiency, Patent Document 4 includes a pipe-shaped anode and a cylindrical cathode, and is electrically connected to the cathode on the inner periphery of the cathode. There has been proposed a metal recovery device in which a net-like or lath-like cylinder is arranged.

  In the collection device of Patent Document 4, the net-like or lath-like cylinder disposed on the inner periphery of the cathode is formed by the electrodeposition metal and the anode when electrolysis proceeds and the metal electrodeposited on the cathode peels from the cathode. It is arranged to prevent the occurrence of short circuit due to contact. According to FIG. 1 of Patent Document 4, the net-like or lath-like cylinders are arranged with spaces (spaces) without being in close contact with the cathode. Further, a part of the metal electrodeposited on the cathode surface is peeled off from the cathode and deposited below the cathode.

Patent Document 1: Japanese Patent Laid-Open No. 61-104096 Patent Document 2: Japanese Patent Laid-Open No. 2006-70364 Patent Document 3: Japanese Patent Laid-Open No. 2005-314742 Patent Document 4: Japanese Patent Laid-Open No. 2006-28555

  An object of the present invention is an apparatus used for recovering metal from a metal-containing solution by electrolysis, which can realize space saving and reduction in equipment load, and can recover metal in a short time. It is to provide an extremely excellent device.

  The metal recovery apparatus according to the present invention that has solved the above problems is an apparatus that recovers metal by electrolyzing a metal-containing solution, and the apparatus rotates in a columnar or cylindrical shape that rotates about an axis. A cathode, an anode arranged to face the rotating cathode, and a mesh-like or porous conductor, and at least a part of the surface of the rotating cathode facing the anode is The point is that it is covered with a conductor.

  In the metal recovery apparatus of the present invention, for example, a noble metal can be recovered from a noble metal-containing aqueous solution.

  As the conductor, for example, a metal net having an average aperture of 0.5 to 3 mm or a metal net having an average wire diameter of 0.3 to 0.5 mm is preferably used. More preferably, it is desirable to use a metal net having an average aperture of 0.5 to 3 mm and an average wire diameter of 0.3 to 0.5 mm. In addition, it is also preferable to use the porous body which has an opening part equivalent to the average opening and average wire diameter of the said range as said conductor.

  Another metal recovery apparatus of the present invention includes a columnar or cylindrical rotating cathode that rotates about an axis, and an anode disposed so as to face the rotating cathode, and the rotating cathode facing the anode. At least a part of the surface has a gist in that it is processed into irregularities. Moreover, it is preferable that at least a part of the surface of the rotating cathode facing the anode is covered with a net-like or porous conductor.

According to the present invention, at least a part of the surface of the rotating cathode facing the anode is covered and covered with a net-like / porous conductor, or the rotating cathode itself is processed to have irregularities on the surface. Therefore, in addition to the effect of improving the metal recovery efficiency by adopting the rotating cathode, the following effects are remarkably exhibited.
(1) The surface area of the cathode is increased, and the metal recovery efficiency is dramatically improved.
(2) Since the electrodeposition property of the metal on the cathode is improved, the metal once electrodeposited on the cathode can be prevented from peeling. Therefore, it is not necessary to separately provide a special mechanism for collecting the metal peeled off from the cathode, and the space saving of the collecting device can be realized.
(3) If a cathode that has been processed per se is used, the durability can be improved because there is no problem of deterioration or peeling of the conductor due to repeated use, as compared to the case where the cathode is coated with the conductor.

FIG. 1 is a schematic explanatory view showing a cross section of the metal recovery apparatus of the first embodiment. FIG. 2 is a graph showing a change in the Au concentration (mg / L) of the treatment liquid with respect to the electrolysis time (hr). FIG. 3 is a graph showing a change in Au concentration (mg / L) of the treatment liquid with respect to electrolysis time (hr). FIG. 4A is a perspective view showing a cylindrical rotating cathode used in the metal recovery apparatus of the second embodiment, and FIG. 4B is a cross-sectional view of the surface of the cylindrical rotating cathode shown in FIG. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolysis tank 2 Anode 3 Rotating shaft 4 Cylindrical rotating cathode 5 Motor 6 Circulating tank 7 Pump 8 Conductor (titanium net)

  The inventors of the present invention have been intensively studied to provide a recovery device that can save the space of the device and reduce the equipment load and is excellent in metal recovery efficiency. As a result, in order to increase the surface area of the rotating cathode, at least a part of the surface of the rotating cathode facing the anode is coated with a net-like or porous conductor, or the surface of the rotating cathode facing the anode is covered. If at least a part is processed into irregularities, the electrodeposition property of the metal electrodeposited on the rotating cathode can be improved, and peeling of the metal once electrodeposited on the rotating cathode can be effectively prevented. The inventors found that the efficiency was remarkably improved and completed the present invention.

  Hereinafter, for convenience of explanation, a recovery device using a rotating cathode in which at least a part of the surface facing the anode is coated with a net-like or porous conductor is referred to as “first embodiment”, the surface facing the anode. A recovery device using a rotating cathode in which at least a part of the surface is processed to be uneven may be referred to as a “second embodiment”.

  The first embodiment and the second embodiment are common in that the surface area of the rotating cathode is preferably increased by 3.0 times or more to increase the metal recovery efficiency. In addition, since all the embodiments result in unevenness on the surface of the rotating cathode, they are common in that the electrodeposition property and peeling resistance of the metal are improved. However, the specific means of both are different, and in the first embodiment, the “external means” for covering the rotating cathode with a conductor is applied, whereas in the second embodiment, the rotating means is rotated. The difference is that “internal means” for forming irregularities on the surface by processing the cathode itself is applied. However, the recovery device of the present invention is not limited to these embodiments, and it is of course possible to change the design within a range that does not impair the gist of the present invention.

First embodiment
The metal recovery apparatus according to the present embodiment includes a columnar or cylindrical rotating cathode that rotates about an axis, an anode disposed so as to face the rotating cathode, a net-like or porous conductor, And at least a part of the surface of the rotating cathode facing the anode is covered with the conductor.

  First, a “network-like or porous conductor” that characterizes this embodiment most will be described. The shape of the conductor used in the present embodiment is a net shape (including a lattice shape) or a porous shape (hereinafter, sometimes referred to as “net-like / porous shape”). The net-like or grid-like form is not particularly limited, and may be a form in which the wires extending in the vertical direction and the horizontal direction intersect, or a form in which the wires extending in the oblique direction with respect to the vertical direction intersect. There may be. There is no particular limitation on the interval between the mesh-like or grid-like openings, and the conductors are configured so that one direction is dense and the other is sparse so that the shape of the openings is rectangular. Alternatively, the shape of the mesh-like or lattice-like opening may be a rhombus or a square. Further, a porous shape having a plurality of holes passing therethrough such as punching metal and expanded metal is also used.

  In addition, the “conductor” needs to be insoluble so as to be electrolyzed and not to be dissolved in a metal-containing solution (that is, an electrolytic solution) and to be eluted during electrolysis. Specifically, for example, titanium or stainless steel, or the metal itself to be collected may be used.

  The “network-like or porous conductor” is coated so as to cover at least a part of the rotating cathode, and the coated rotating cathode surface is disposed so as to face the anode. There is no space in the portion where the conductor and the rotating cathode are in contact as in Patent Document 4 described above. In this way, a part of the surface of the rotating cathode facing the anode is covered with a net-like or porous conductor without gaps, so that the surface of the rotating cathode is uneven, and metal is electrodeposited on the uneven surface. Thus, the electrodeposited metal is remarkably improved because it is difficult to peel off from the surface of the rotating cathode. Moreover, since the surface area of a rotating cathode increases by employ | adopting the said structure, electrolysis efficiency improves and the collection | recovery efficiency of a metal is raised.

  The conductor does not need to be provided on the entire surface of the rotating cathode facing the anode, and is provided on at least a part of the rotating cathode as long as the electrolytic efficiency is reduced and the metal recovery efficiency is not hindered. Just do it.

  When the mesh-like or porous conductor is a metal mesh, it is preferable that the average aperture is 0.5 to 3 mm or the average wire diameter is 0.3 to 0.5 mm. In addition, an average is the value calculated | required by measuring the opening and wire diameter in several places of a metal net | network, and averaging this.

  If the average opening of the metal mesh is less than 0.5 mm, the eyes are clogged too much, and if the average opening exceeds 3 mm, the eyes are too coarse, so that the stirring effect of the treatment liquid is reduced, or the rotating cathode Therefore, the effect of increasing the electrolysis efficiency and improving the metal recovery efficiency is hardly exhibited.

  When the average wire diameter of the wire constituting the metal net is less than 0.3 mm, the wire diameter is too small, and when the average wire diameter exceeds 0.5 mm, the wire diameter is too large, so that the stirring effect of the treatment liquid is reduced. In addition, the area of the rotating cathode cannot be increased, and the effect of improving electrolysis efficiency and improving metal recovery efficiency is hardly exhibited.

  In particular, the metal mesh preferably has an average opening of 0.5 to 3 mm and an average wire diameter of 0.3 to 0.5 mm.

  When the mesh-like or porous conductor is a porous body, a porous body having openings corresponding to the average openings and average wire diameters in the above range should be used. preferable.

  The metal mesh is preferably attached to the surface of the rotating cathode so as to be two to four layers. By setting the number of windings of the metal net to two or more turns, the area of the rotating cathode can be sufficiently increased, and the metal recovery efficiency can be further increased. However, even if the metal mesh is wound more than four times, the effect of attaching the metal mesh is saturated and the recovery efficiency of the metal hardly changes. Therefore, the number of turns of the metal mesh is preferably four or less. .

  A method for coating the surface of the rotating cathode with a mesh-like or porous conductor is not particularly defined. Fix it so that there is no gap.

<< Second Embodiment >>
The metal recovery apparatus according to the present embodiment includes a columnar or cylindrical rotary cathode that rotates about an axis, and an anode that is disposed so as to face the rotary cathode, and the rotation that faces the anode. It is characterized in that at least a part of the surface of the cathode is processed into irregularities. By providing irregularities on the surface of the rotating cathode itself to increase the surface area of the rotating cathode, it is possible to increase the metal recovery efficiency, and it is possible to repeatedly use the rotating cathode over a long period of time. That is, in the configuration in which the conductor is coated on the surface of the rotating cathode as in the first embodiment, the conductor coated on the surface is separated from the surface of the rotating cathode by using the rotating cathode for a long time. There is a fear. This is because, when used for a long period of time, the wire diameter of the conductor is reduced, the mesh is loosened, and the welded part may come off. On the other hand, in the second embodiment, since the surface area is increased without processing the rotating cathode itself and using the conductor, the above-described problem caused by the conductor does not occur. Therefore, stable operation over a long period of time is possible.

  The unevenness may be provided on at least a part of the surface of the rotating cathode, and is not necessarily provided on the entire surface. This is because, as described above, in this embodiment, it is sufficient that the unevenness is formed so that the surface area after processing into the unevenness is approximately 3.0 times or more compared to before processing. Further, the shape of the unevenness formed on the surface can be changed by a processing means to be described later, for example, fine unevenness is formed by shot blasting, and recesses of grooves and holes are formed by cutting. . Alternatively, it may be processed into a skin pattern or the like by special processing. Moreover, although the preferable range of the uneven | corrugated average space | interval and the average height of unevenness (difference between a convex part and a recessed part) changes with shapes, sizes, etc. of the rotating cathode to be used, all are 0.5 mm or more in general. It is preferable that A preferred form of the recess will be described in detail using the apparatus shown in FIG.

  The form of the unevenness processed on the surface of the rotating cathode is not particularly limited. For example, the recess may be a recess formed intermittently shallowly (hereinafter may be referred to as a hole) or a groove formed continuously along the cathode surface. Or you may form an unevenness | corrugation in the surface of a rotating cathode by combining a hole and a groove | channel suitably.

  The cross-sectional shape of the concavo-convex portion is not particularly limited, and the shape when the cross-section perpendicular to the cathode surface is observed is any of, for example, a rectangle, a polygon, a U shape, a V shape, a W shape, and a waveform. May be.

  The appearance of the concavo-convex part is not particularly limited, and may be, for example, a linear shape, a curved shape, a rectangular shape, a polygonal shape, a circular shape, or a skin-like pattern. Moreover, you may form an unevenness | corrugation in the surface of a rotating cathode combining these suitably.

  The processing method of the unevenness is not particularly limited, and the unevenness may be formed by performing a known roughening treatment on the surface of the rotating cathode. Examples of the roughening treatment include cutting, blasting, electric discharge machining, laser machining, and etching. Alternatively, a plate as a material for the rotating cathode may be press-molded and processed so that the cross-sectional shape is, for example, V-shaped, W-shaped, corrugated, and the like, and this may be rounded into a cylindrical shape to form a rotating cathode. Moreover, as a metal used as the material of the rotating cathode, for example, a material obtained by sintering sponge-like Ti having a large void by powder metallurgy may be used as the rotating cathode.

  In the second embodiment, the surface of the rotating cathode having irregularities may be further coated with the above-described net-like or porous conductor. By covering the conductor, the surface area of the rotating cathode can be further increased. For example, Experimental Example 23 to be described later is an example in which a titanium mesh is wound around the surface of the grooved rotary cathode shown in FIG. 4, but the titanium mesh is 1 on the surface of the grooveless rotary cathode shown in FIG. The surface area increased as compared with Experimental Example 9 wound around, and the metal could be recovered in a short time. In the embodiment in which the conductor is coated on the surface of the rotating cathode provided with the groove, the surface area of the rotating cathode can be increased in combination with the effect of increasing the surface area by providing irregularities on the surface of the rotating cathode even if the conductor is wound once. it can. As a result, the metal can be recovered in a short time.

  The surface area of the rotating cathode used in the first embodiment and the second embodiment is about 3.0 times or more of the surface area of the rotating cathode before coating with a conductor or before processing the unevenness. Is preferred. More preferably, it is 3.3 times or more, and further preferably 3.5 times or more. The surface area of the rotating cathode is preferably as large as possible. However, if a mesh-like or porous conductor is wound too much, the rotating cathode becomes too heavy and the rotation is overloaded, and the increase in surface area due to the unevenness forming means is limited. Therefore, even if many estimates are made, the upper limit is about 10 times. More preferably, it is 8 times or less, More preferably, it is 6 times or less.

  The rotating cathode used in the first embodiment and the second embodiment is a columnar or cylindrical rotating cathode that rotates about an axis. By using such a rotating cathode, the electrolysis efficiency is improved and the metal recovery efficiency is further enhanced. In the present invention, compared with the case where the disk-shaped rotating cathode as in Patent Document 2 and Patent Document 3 is used, the electrolytic solution can be sufficiently stirred at a lower number of revolutions, so that the equipment load can be reduced.

  Here, “columnar” means a solid body or a shape that internally holds a space that does not communicate with the outside, and “tubular” refers to a hollow body that internally possesses a space that communicates with the outside. Means. In the present invention, any aspect is preferably used. The rotating cathode used in the present invention is typically substantially columnar or cylindrical. The cross-sectional shape of the rotating cathode is not limited to a circle, and may be, for example, a “polygonal” form extremely close to a circle. However, if the cross-sectional shape of the rotating cathode is a rectangle (for example, a square), the resistance received from the solution when the cathode is rotated increases, so a load is applied to the power of the motor or the like provided to rotate the cathode. Since it may take too much or the electrolytic solution may scatter, it may be selected appropriately in consideration of equipment load.

  The material of the rotating cathode may be insoluble so long as it has electroconductivity to the extent that it can be electrolyzed and does not dissolve in the metal-containing solution (that is, the electrolytic solution) and does not dissolve during electrolysis. Specifically, for example, titanium or stainless steel, or the metal itself to be collected may be used.

  The rotating cathode and the anode can be arranged as follows.

  First, when a columnar rotating cathode is used, the anode is disposed outside (outer periphery) of the columnar rotating cathode. The shape of the anode arranged around the columnar rotating cathode is not particularly limited, and those commonly used in metal recovery devices can be employed. Accordingly, either a plate-like or cylindrical anode can be used. Specifically, a plate-like or cylindrical anode may be disposed so as to surround the periphery (outer periphery) of the columnar rotating cathode. When a plate-like anode is used, the plate-like anode is disposed so as to face the surface of the columnar rotary cathode coated with a net-like or porous conductor or the surface of the columnar rotary cathode provided with irregularities. A plurality of such plate-like anodes may be arranged so as to surround the periphery of the columnar rotary cathode.

  On the other hand, when a cylindrical rotating cathode is used, the anode may be disposed outside the cylindrical rotating cathode or may be disposed inside the cylindrical rotating cathode.

  The shape and arrangement method of the anode arranged around (outside / inside) the cylindrical rotating cathode is substantially the same as when the above-described columnar rotating cathode is used.

  When the anode is disposed inside the cylindrical cathode, in the first embodiment, the above-described network / porous conductor may be provided on at least the inner surface of the cylindrical rotating cathode, and if necessary. In addition, it may be provided on the outer surface of the cylindrical rotating cathode. Moreover, in 2nd embodiment, what is necessary is just to provide an unevenness | corrugation in the at least inner surface of a cylindrical rotating cathode, and you may provide an unevenness | corrugation also in the outer surface of a cylindrical rotating cathode as needed. Further, the anode may be arranged near the central axis of the cylindrical rotating cathode, or may be arranged avoiding the vicinity of the central axis of the cylindrical rotating cathode.

  In the present invention, a rotary cathode is used in which a columnar or cylindrical cathode is configured to be rotatable around the axis of the cathode. By performing the electrolysis while rotating the cathode, the solution (electrolyte) in the electrolytic cell is agitated, so that the contact between the solution and the cathode is effectively performed, the metal recovery efficiency is improved, and the time is shortened. The metal can be recovered.

  The rotating cathode can be connected to power such as a motor installed in the apparatus and rotated. The peripheral speed (rotational speed) of the rotating cathode varies depending on the size of the electrolytic cell to be used, the amount of solution supplied to the electrolytic cell, or the type of metal to be collected, but it is difficult to uniquely determine it. For example, when recovering precious metals, it is preferable to generally control the peripheral speed within a range of 0.5 to 1.8 m / sec.

  This is because if the peripheral speed of the cathode is less than 0.5 m / sec, the treatment liquid in the electrolytic cell is not stirred and the treatment liquid stays in the vicinity of the surface of the rotating cathode, and it is difficult to increase the electrolysis efficiency. Therefore, the peripheral speed of the cathode is preferably 0.5 m / sec or more. More preferably, it is 0.7 m / sec or more.

  However, if the peripheral speed of the cathode exceeds 1.8 m / sec, bubbling occurs in the treatment liquid, the electrolysis reaction at the rotating cathode is inhibited, and the electrolysis efficiency is lowered. Further, if the peripheral speed of the cathode is increased too much, the processing solution will be rippled and the processing solution will overflow from the electrolytic cell, resulting in poor safety. Therefore, the peripheral speed of the cathode is preferably 1.8 m / sec or less. More preferably, it is 1.6 m / sec or less, More preferably, it is 1.5 m / sec or less.

  Examples of metal elements that can be recovered by applying the apparatus of the present invention include noble metal elements, Cu, Ni, and the like. Examples of the noble metal element include Au and Ag, or platinum group elements (Pd, Pt, Ir, Ru, and Rh). In particular, if the recovery device of the present invention is used, an expensive noble metal element such as Au can be recovered in a shorter time and at a lower cost than conventional ones. Therefore, the recovery device of the present invention is a precious metal recovery device from a solution. As extremely useful.

  The metal-containing solution used in the present invention is only required to contain the above-mentioned metal, and typically includes plating waste liquid, photographic development waste liquid, liquid obtained by washing a plated product, stripping liquid waste liquid, and the like. .

  The electrolysis conditions for electrolyzing the metal-containing solution using the recovery device are not particularly limited. For example, the voltage may be 1 to 10 V and the current may be about 10 to 25 A.

  After electrolysis and electrodeposition of the metal from the metal-containing solution onto the cathode surface, the cathode is taken out of the recovery device, and the cathode is immersed in a solution in which the metal to be recovered is dissolved to elute the metal and recover it. do it.

  Next, the metal recovery apparatus of the present invention will be described more specifically with reference to the drawings.

  FIG. 1 is a sectional view of a metal recovery apparatus according to a first embodiment of the present invention. FIG. 6 is a cross-sectional view of a recovery device in which a cylindrical rotating cathode 4 coated so that a net-like or porous conductor 8 is in close contact with the surface and the anode 2 is disposed so as to surround the outer side of the rotating cathode 4. is there. In FIG. 1, 1 is an electrolytic cell, 3 is a rotating shaft, 5 is a motor, 6 is a circulation tank, and 7 is a pump. Note that the metal recovery apparatus shown in FIG. 1 is an embodiment showing an example of the present invention, and is not intended to be limited to this.

  The metal recovery apparatus shown in FIG. 1 includes a cylindrical rotating cathode 4 that rotates about an axis, four plate-like anodes 2 disposed so as to face the cylindrical rotating cathode 4, and a net-like or porous material. And an electric conductor (titanium net) 8. At least a part of the surface of the rotating cathode 4 facing the plate-like anode 2 is covered with a titanium mesh 8. In Experimental Examples 1 to 20 to be described later, experiments were performed using this recovery apparatus.

  FIG. 4A is a perspective view showing a cylindrical rotating cathode 4a used in the second embodiment of the metal recovery apparatus according to the present invention. FIG. 4B is an enlarged view of a portion surrounded by a square of the cylindrical rotating cathode 4a shown in FIG. On the surface of the cylindrical rotating cathode 4a shown in (A), concave portions (grooves) having a fixed shape are regularly provided on the entire surface. As shown in (B), the groove has a width x, a groove-to-groove interval y, and a groove depth z.

  The grooves may be formed in the horizontal direction along the circumference of the rotating cathode, or may be formed in the vertical direction so as to be parallel to the axis of the rotating cathode. A lattice shape in which grooves are formed in both the vertical direction and the horizontal direction may be used, or a groove may be formed in a diagonal direction with respect to the vertical direction to form a rhombus lattice shape.

  The size x of the recess is preferably 0.5 mm or more, more preferably 1 mm or more, and still more preferably 1.5 mm or more. The size of the recess means the width of the groove when the recess is a groove, and the equivalent circle diameter of the opening when the recess is a hole. The width of the groove may be the maximum value when the distance between the wall surfaces in the horizontal direction is measured when a cross section perpendicular to the cathode surface is observed.

  The interval y between the recesses is preferably 0.5 mm or more, more preferably 1 mm or more, and further preferably 1.5 mm or more. In addition, the space | interval of a recessed part means the space | interval of a groove | channel, a space | interval of a hole, a space | interval of a groove | channel, and a space | interval of a groove | channel.

  The depth z of the concavo-convex portion is preferably 0.5 mm or more, more preferably 1 mm or more, and further preferably 1.5 mm or more. The depth of the concavo-convex portion means the maximum value when the distance in the vertical direction from the opening is measured when a cross section perpendicular to the cathode surface is observed.

  In Experimental Examples 21 to 24 to be described later, experiments were performed using a metal recovery apparatus to which the cylindrical rotating cathode 4a illustrated in FIG. 4 was attached. In Experimental Example 23 to be described later, an experiment was performed using a cylindrical rotating cathode (not shown) in which the surface of the cylindrical rotating cathode 4a in which the groove was formed was further covered with a titanium mesh.

  Hereinafter, the present invention will be described in more detail with reference to experimental examples, but the following experimental examples are not intended to limit the present invention, and may be implemented with appropriate modifications within a range that can meet the purpose described above and below. These are all possible and are within the scope of the present invention.

(Experimental example 1)
Experimental Example 1 and Experimental Examples 2 to 10 described later were performed in order to examine the recovery efficiency when Au was recovered from the Au-containing cyan plating product washing water.

  In Experimental Example 1, Au was recovered as follows using the metal recovery apparatus shown in FIG. 1 described above.

  A cylindrical rotating cathode 4 is attached to a rotating shaft 3 disposed at the center of the electrolytic cell 1 (capacity is 10 L). The cylindrical rotating cathode 4 operates the motor 5 to operate the rotating shaft 3. It can be rotated in the circumferential direction as the center.

  The cylindrical rotating cathode 4 is made of titanium and has a cylindrical shape having a diameter of 160 mm and a length of 200 mm. The outer surface has an average opening of 1 mm and an average wire diameter of 0.3 mm (20 mesh) as the conductor 8. Titanium mesh is wound twice. The titanium mesh is attached by spot welding so as to be in close contact with the surface of the cylindrical rotating cathode 4.

  When the surface area is calculated without considering the portion where the cylindrical rotating cathode 4 and the titanium mesh contact, the surface area when the titanium mesh is attached to the surface of the cylindrical rotating cathode 4 is titanium. The surface area of the cylindrical rotating cathode 4 not attached to the net increased by about 3.9 times.

  The inner wall surface of the electrolytic cell 1 is provided with a total of four plate-like insoluble anodes (100 mm × 250 mm) on each wall surface.

  The electrolytic bath 1 is filled with 30 L of an Au-containing cyan plating product washing water having an Au concentration of 97 mg / L as a treatment liquid, and the treatment liquid overflowing from the electrolytic tank 1 is stored in the circulation tank 6. The pump 7 was supplied from the circulation tank 6 to the vicinity of the bottom of the electrolytic cell 1 and circulated in the electrolytic cell 1.

  The amount of liquid circulating in the electrolytic cell 1 was 10 L / min, the voltage was 4 to 6 V, the current was 12 A, and the peripheral speed of the cylindrical rotating cathode 4 was 1.0 m / sec (rotation speed 120 rpm). .

  Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. Further, the change in Au concentration (mg / L) of the treatment liquid with respect to the electrolysis time (hr) is shown by ▪ in FIG.

  As is apparent from Table 1 below, when the electrolysis was performed for 3 hours, the Au concentration of the treatment liquid decreased to 1 mg / L, and the Au in the treatment liquid was electrodeposited on the surface of the cylindrical rotating cathode 4.

(Experimental example 2)
In Experimental Example 2, the influence of the titanium mesh on Au recovery efficiency was examined. Specifically, in Example 1 above, except that the cylindrical rotating cathode 4 having a diameter of 160 mm and a length of 200 mm in which the surface of the cylindrical rotating cathode 4 is not provided with a titanium mesh is used, The treatment solution was electrolyzed under the same conditions. Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. Further, the change in Au concentration (mg / L) of the treatment liquid with respect to the electrolysis time (hr) is shown by ♦ in FIG.

  As apparent from Table 1 below, it took 15 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  Comparing the results of Experimental Example 2 with the results of Experimental Example 1, the result of Experimental Example 2 shows that the time required to reduce the Au concentration of the treatment liquid to 1 mg / L is about five times. Therefore, it can be seen that the recovery efficiency of Au can be improved by about 5 times only by providing a titanium mesh on the surface of the cylindrical rotating cathode 4 to increase the surface area by about 3.9 times.

(Experimental example 3)
In Experimental Example 3, the influence of the peripheral speed of the rotating cathode on the Au recovery efficiency was examined.

  In Experimental Example 2, the treatment liquid was electrolyzed under the same conditions as in Experimental Example 2 except that the peripheral speed of the cylindrical rotating cathode 4 was increased to 2.0 m / sec (rotational speed 240 rpm). Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. Further, the change in Au concentration (mg / L) of the treatment liquid with respect to the electrolysis time (hr) is shown by ▲ in FIG.

  As apparent from Table 1 below, it took 12 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  Comparing the results of Experimental Example 3 with the results of Experimental Example 2 above, even if the peripheral speed of the cylindrical rotating cathode 4 is doubled, the electrolysis time can be shortened by 3 hours, and the Au recovery efficiency is only about 20%. It did not improve.

  The peripheral speed of the cylindrical rotating cathode 4 is limited to about 2.0 m / sec (rotation speed 240 rpm). If the peripheral speed is increased beyond this, the spilling of the treatment liquid increases, and safe operation cannot be performed.

  As can be seen from FIG. 2, by providing a titanium mesh on the surface of the cylindrical rotating cathode 4 rather than providing a titanium mesh on the surface of the cylindrical rotating cathode 4 (♦ and ▲ in FIG. 2). (■ in FIG. 2), it can be seen that the electrolysis time is remarkably shortened, and the Au recovery efficiency is remarkably improved.

(Experimental example 4)
Experimental Example 4 and Experimental Example 5 described later are other experiments in which the influence of the peripheral speed of the rotating cathode on the Au recovery efficiency was examined.

  In the above experimental example 1, the treatment liquid was electrolyzed under the same conditions as in the above experimental example 1 except that the peripheral speed of the cylindrical rotating cathode 4 was reduced to 1/3, 0.3 m / sec (rotation speed 40 rpm). . Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As apparent from Table 1 below, it took 6 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  Comparing the results of Experimental Example 4 with the results of Experimental Example 1, it was found that if the peripheral speed of the cylindrical rotating cathode 4 is made too small, the electrolysis time becomes longer and the Au recovery efficiency cannot be improved much. . The reason why the recovery efficiency cannot be improved is thought to be due to insufficient stirring of the treatment liquid, and it is considered that the electrolysis reaction has become difficult to proceed.

(Experimental example 5)
In Experimental Example 1, the treatment liquid was electrolyzed under the same conditions as in Experimental Example 1 except that the peripheral speed of the cylindrical rotating cathode 4 was increased to 2.0 m / sec (rotational speed 240 rpm). Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As apparent from Table 1 below, it took 5 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  Comparing the result of Experimental Example 5 with the result of Experimental Example 1, the result of Experimental Example 5 shows that the time required to reduce the Au concentration of the treatment liquid to 1 mg / L is about 1.7 times, and is cylindrical. It has been found that when the peripheral speed of the rotating cathode 4 is too high, the Au recovery efficiency deteriorates. The recovery efficiency of Au deteriorated because the peripheral speed was too high, the bubbling of the processing liquid was generated, and the contact area between the cylindrical rotating cathode 4 and the processing liquid was reduced by the generated bubbles, resulting in an electrolysis reaction. This is thought to be because it became difficult to proceed.

  As is clear from Table 1 below, the Au recovery time becomes longer than the result of Experimental Example 1 and the Au recovery efficiency, regardless of whether the peripheral speed of the cylindrical rotating cathode 4 is too small or too high. It turns out that there is not much improvement.

(Experimental example 6)
Experimental Example 6 and Experimental Examples 7 and 8 to be described later are experiments in which the influence of the titanium mesh opening and wire diameter on Au recovery efficiency was examined.

  In Experimental Example 1, the treatment solution was electrolyzed under the same conditions as in Experimental Example 1 except that a mesh having an average opening of 5 mm and an average wire diameter of 1 mm (4 mesh) was used as the titanium mesh. When the surface area is calculated without considering the portion where the cylindrical rotating cathode 4 and the titanium mesh contact, the surface area when the titanium mesh is attached to the surface of the cylindrical rotating cathode 4 is titanium. The increase was about 3.1 times the surface area of the cylindrical rotating cathode 4 not attached to the net.

  Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As apparent from Table 1 below, it took 6 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  Comparing the results of Experimental Example 6 with the results of Experimental Example 1 described above, it was found that when a mesh with too coarse mesh was used as the titanium mesh, it took time to recover Au and the recovery efficiency of Au was not improved much. It was.

(Experimental example 7)
In Experimental Example 1, the treatment liquid was electrolyzed under the same conditions as in Experimental Example 1 except that a mesh having an average opening of 2 mm and an average wire diameter of 0.5 mm (10 mesh) was used as the titanium mesh. did. When the surface area is calculated without considering the portion where the cylindrical rotating cathode 4 and the titanium mesh contact, the surface area when the titanium mesh is attached to the surface of the cylindrical rotating cathode 4 is titanium. The increase was about 3.5 times the surface area of the cylindrical rotating cathode 4 that was not attached to the net.

  Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As is apparent from Table 1 below, when the electrolysis was performed for 4 hours, the Au concentration of the treatment liquid decreased to less than 1 mg / L.

  Comparing the results of Experimental Example 7 with the results of Experimental Example 1 above, the time required for the Au concentration of the processing solution to reach about 1 mg / L is almost the same regardless of whether the titanium mesh is 10 mesh or 20 mesh. The efficiency was almost the same.

(Experimental example 8)
In Experimental Example 1, the treatment liquid was used under the same conditions as in Experimental Example 1 except that a mesh having an average aperture of 0.3 mm and an average wire diameter of 0.1 mm (60 mesh) was used as the titanium mesh. Electrolyzed. When the surface area is calculated without considering the portion where the cylindrical rotating cathode 4 and the titanium mesh contact, the surface area when the titanium mesh is attached to the surface of the cylindrical rotating cathode 4 is titanium. The increase was about 4.1 times the surface area of the cylindrical rotating cathode 4 not attached to the net.

  Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As apparent from Table 1 below, it took 5 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  Comparing the results of Experimental Example 8 with the results of Experimental Example 1, it was found that even when a mesh with too fine mesh was used as the titanium mesh, the electrolysis time could not be shortened much and the Au recovery efficiency could not be improved.

  As apparent from Table 1 below, even if the mesh of the titanium mesh is too coarse or too fine, it takes longer to recover Au than the results of Experimental Example 1 and Experimental Example 7, It can be seen that the recovery efficiency of Au has not been improved.

(Experimental example 9)
Experimental Example 9 and Experimental Example 10 described later are experiments in which the influence of the number of turns of the titanium net on the Au recovery efficiency was examined.

  In Experimental Example 1, the treatment solution was electrolyzed under the same conditions as in Experimental Example 1 except that the number of turns of the titanium mesh wound around the surface of the cylindrical rotating cathode 4 was single. When the surface area is calculated without considering the portion where the cylindrical rotating cathode 4 and the titanium mesh contact, the surface area when the titanium mesh is attached to the surface of the cylindrical rotating cathode 4 is titanium. The increase was about 2.4 times the surface area of the cylindrical rotating cathode 4 not attached to the net.

  Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As apparent from Table 1 below, it took 5 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  Comparing the result of Experimental Example 9 with the result of Experimental Example 1 described above, if the number of turns of the titanium mesh wound around the surface of the cylindrical rotating cathode 4 is excessively reduced, it is difficult to sufficiently obtain the effect of winding the titanium mesh. Recognize.

(Experimental example 10)
In Experimental Example 1, the treatment solution was electrolyzed under the same conditions as in Experimental Example 1 except that the number of turns of the titanium mesh wound around the surface of the cylindrical rotating cathode 4 was quadrupled. When the surface area is calculated without considering the portion where the cylindrical rotating cathode 4 and the titanium mesh contact, the surface area when the titanium mesh is attached to the surface of the cylindrical rotating cathode 4 is titanium. The increase was about 6.8 times the surface area of the cylindrical rotating cathode 4 not attached to the net.

  Table 1 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As is clear from Table 1 below, when the electrolysis was performed for 3 hours, the Au concentration of the treatment liquid decreased to 1 mg / L.

  Comparing the results of Experimental Example 10 with the results of Experimental Example 1, it can be seen that the effect of winding the titanium mesh is saturated even if the number of turns of the titanium mesh wound around the surface of the cylindrical rotating cathode 4 is increased excessively.

  As is clear from Table 1 below, if the number of turns of the titanium mesh is reduced too much, the electrolysis time becomes longer than the results of Experimental Example 1 and Experimental Example 10, and it is difficult to improve the Au recovery efficiency. I understand that.

(Experimental example 11)
In Experimental Example 11 and Experimental Examples 12 and 13 to be described later, the influence of the titanium net when the Au recovery process was repeatedly performed was examined.

  In the experimental example 1, 30L of Au-containing cyan plating product washing water as a treatment liquid is filled in the metal recovery apparatus shown in FIG. 1, and electrolysis is performed until the Au concentration of the waste liquid becomes 1 mg / L, and then cylindrical. The process of filling a new Au-containing cyan plating product washing water 30 L without collecting Au electrodeposited on the rotating cathode 4 was repeated 30 times. The Au concentration of the Au-containing cyan plating product washing water is 97 mg / L. The amount of Au deposited on the bottom of the electrolytic cell 1 after the electrodeposited Au on the cylindrical rotating cathode 4 was measured. The measurement results are shown in Table 2 below.

  In addition, 900 L was used in total as the Au-containing cyan plating product washing water. The total amount of Au contained in the waste liquid was 87.3 g.

  As is clear from Table 2 below, after 30 times of electrolysis, the amount of Au electrodeposited on the cylindrical rotating cathode 4 is 86.1 g, and the amount of Au deposited on the bottom of the electrolytic cell is It was 0.3 g. Therefore, the rate of Au peeled from the cylindrical rotating cathode 4 was 0.3%.

(Experimental example 12)
In the experimental example 11, the treatment liquid was used under the same conditions as in the experimental example 11 except that the cylindrical rotating cathode 4 having a diameter of 160 mm and a length of 200 mm without a titanium mesh on the surface was used as the cylindrical rotating cathode 4. Was electrolyzed.

  As is clear from Table 2 below, after 30 times of electrolysis, the amount of Au electrodeposited on the cylindrical rotating cathode 4 is 81.3 g, and the amount of Au deposited on the bottom of the electrolytic cell is It was 5.1 g. Therefore, the Au ratio peeled from the cylindrical rotating cathode 4 was 5.8%.

(Experimental example 13)
In the experimental example 11, when the titanium mesh is wound around the surface of the cylindrical rotating cathode 4, the titanium mesh and the upper portion of the cylindrical rotating cathode are connected by a conductive wire, and the titanium mesh is the surface of the cylindrical rotating cathode 4. In order to prevent the treatment liquid from being discharged under the same conditions as in Experimental Example 11, except that a cylindrical rotating cathode 4 wound in a double space after a spacer was inserted and a gap of about 1 mm was used. Disassembled.

  As is apparent from Table 2 below, the amount of Au electrodeposited on the cylindrical rotating cathode 4 after 30 times of electrolysis was 85.0 g, and the amount of Au deposited on the bottom of the electrolytic cell was It was 1.4 g. Therefore, the rate of Au peeled from the cylindrical rotating cathode 4 was 1.6%.

  Comparing the results of the above experimental examples 11 to 13, the electrodeposition on the cylindrical rotating cathode 4 can be improved by attaching a titanium mesh to the surface of the cylindrical rotating cathode 4. It can be seen that Au can be recovered from the surface of 4 without peeling off. Therefore, it is not necessary to separately provide a special mechanism for recovering the metal peeled off from the surface of the cylindrical rotating cathode 4, and space saving of the recovery device can be realized.

(Experimental example 14)
Experimental Example 14 and Experimental Examples 15 and 16 to be described later are experiments in which the recovery efficiency when Au was recovered from the waste liquid of the Au-containing aqua repellent liquid was investigated.

  In Experimental Example 1, except that the waste liquid of Au-containing aqua repellent liquid was used as the treatment liquid, and electrolysis was performed with a voltage of 1.0 to 2.0 V and a current of 20 A, the Experimental Example 1 The treatment liquid was electrolyzed under the same conditions. The Au concentration of the waste liquid of the Au-containing aqua repellent liquid is 80 mg / L. Table 3 below shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. Further, the change in Au concentration (mg / L) of the treatment liquid with respect to the electrolysis time (hr) is shown by ■ in FIG.

  As is clear from Table 3 below, when the electrolysis was performed for 6 hours, the Au concentration of the treatment liquid decreased to 3 mg / L. During the lapse of 6 hours, it was not observed that Au electrodeposited on the cylindrical rotating cathode 4 was peeled off.

(Experimental example 15)
In the experimental example 14, the treatment liquid was used under the same conditions as in the experimental example 14 except that the cylindrical rotating cathode 4 having a diameter of 160 mm and a length of 200 mm was used as the cylindrical rotating cathode 4. Was electrolyzed. Table 3 below shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. Further, the change in Au concentration (mg / L) of the treatment liquid with respect to the electrolysis time (hr) is shown by ♦ in FIG.

  As is apparent from Table 3 below, when the electrolysis was performed for 12 hours, the Au concentration of the treatment liquid decreased to 10 mg / L. Thereafter, the electrodeposited Au on the cylindrical rotating cathode 4 was peeled off and re-applied. Since dissolution occurred, an increase in Au concentration was observed.

  In addition, since Au peeled from the cylindrical rotating cathode 4 was dissolved in aqua regia after a while, the amount of peeled Au could not be measured.

(Experimental example 16)
In the experimental example 14, when the titanium mesh is wound around the surface of the cylindrical rotating cathode 4, the titanium mesh and the upper part of the cylindrical rotating cathode are connected by a conductive wire, and the titanium mesh is the surface of the cylindrical rotating cathode 4 In order to prevent the treatment liquid from being discharged under the same conditions as in Experimental Example 14, except that a cylindrical rotating cathode 4 wound in a double space after a spacer is inserted and a gap of about 1 mm is used is used. Disassembled. Table 3 below shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. Further, the change in Au concentration (mg / L) of the treatment liquid with respect to the electrolysis time (hr) is shown by ▲ in FIG.

  As is apparent from Table 3 below, when the electrolysis was performed for 3 hours, Au electrodeposited on the cylindrical rotating cathode 4 was peeled off and redissolved. The Au concentration of the treatment liquid changed around 20 mg / L, and the Au concentration did not decrease any more.

  In addition, since Au peeled from the cylindrical rotating cathode 4 was dissolved in aqua regia after a while, the amount of peeled Au could not be measured.

  As is apparent from FIG. 3 in which the results of Experimental Examples 14 to 16 are plotted, even when the waste liquid of the Au-containing aqua repellent liquid is used as the processing liquid, a cylindrical shape in which a titanium net is attached to the surface It can be seen that by using the rotating cathode 4 (■ in FIG. 3), the electrolysis time can be shortened and the Au recovery efficiency is increased. Further, by using the cylindrical rotating cathode 4 having a titanium mesh attached to the surface (■ in FIG. 3), the Au concentration of the treatment liquid can be reduced to 3 mg / L.

(Experimental example 17)
In Experimental Example 17 and Experimental Example 18 described below, the recovery efficiency when Pd was recovered from the Pd-containing waste liquid was examined.

  In the experimental example 1, except that the Pd-containing waste liquid (Pd concentration is 113 mg / L, pH = 8) is used as the treatment liquid and the electrolysis is performed at a voltage of 7 to 8 V, the above experimental example 1 The treatment solution was electrolyzed under the same conditions. Table 4 shows the results of measuring the Pd concentration of the treatment liquid every several hours after the start of electrolysis.

  As is clear from Table 4 below, when the electrolysis was performed for 6 hours, the Pd concentration of the treatment liquid decreased to 1 mg / L.

(Experiment 18)
In the experimental example 17, the treatment liquid was used under the same conditions as in the experimental example 17 except that the cylindrical rotating cathode 4 having a diameter of 160 mm and a length of 200 mm without a titanium mesh on the surface was used as the cylindrical rotating cathode 4. Was electrolyzed. Table 4 shows the results of measuring the Pd concentration of the treatment liquid every several hours after the start of electrolysis.

  As apparent from Table 4 below, it took 27 hours to reduce the Pd concentration of the treatment liquid to 1 mg / L.

  Comparing the result of Experimental Example 18 with the result of Experimental Example 17, the electrolysis time of Experimental Example 18 is increased by about 4.5 times. Therefore, according to the present invention, titanium is formed on the surface of the cylindrical rotating cathode 4. It can be seen that the recovery efficiency of Pd can be improved by about 4.5 times simply by providing a net and increasing the surface area by about 3.9 times.

  As is apparent from Table 4 below, even when Pd is recovered from the Pd-containing waste liquid, titanium is formed on the surface of the cylindrical rotating cathode 4 more than when no titanium mesh is provided on the surface of the cylindrical rotating cathode 4. It can be seen that by providing the net, the electrolysis time is remarkably shortened and the recovery efficiency of Pd is increased.

(Experimental example 19)
In Experimental Example 19 and Experimental Example 20 described later, the recovery efficiency when Cu was recovered from the Cu-containing sulfuric acid waste liquid was examined.

  In the above experimental example 1, except that the Cu-containing sulfuric acid waste liquid (Cu concentration is 166 mg / L, acid concentration is 1 mol / L) is used as the treatment liquid, and the electrolysis is performed at a voltage of 3 to 4 V. The treatment liquid was electrolyzed under the same conditions as in Experimental Example 1. Table 5 below shows the results of measuring the Cu concentration of the treatment liquid every several hours after the start of electrolysis.

  As is apparent from Table 5 below, when the electrolysis is performed for 3 hours, the Cu concentration of the treatment liquid decreases to 5 mg / L, and when the electrolysis is performed for 6 hours, the Cu concentration of the treatment liquid is less than 1 mg / L. It dropped to.

(Experiment 20)
In the experimental example 19, the treatment liquid was used under the same conditions as in the experimental example 19 except that the cylindrical rotating cathode 4 having a diameter of 160 mm and a length of 200 mm was used as the cylindrical rotating cathode 4. Was electrolyzed. Table 5 below shows the results of measuring the Cu concentration of the treatment liquid every several hours after the start of electrolysis.

  As apparent from Table 5 below, it took 24 hours to reduce the Cu concentration of the treatment liquid to less than 1 mg / L.

  Comparing the results of Experimental Example 20 with the results of Experimental Example 19, in Experimental Example 20, the electrolysis time is about four times longer, and a titanium mesh is provided on the surface of the cylindrical rotating cathode 4 to provide a surface area of about 3 times. It can be seen that the Cu recovery efficiency can be improved by a factor of about 4 only by increasing it by .9 times.

  As is apparent from Table 5 below, by providing a titanium mesh on the surface of the cylindrical rotating cathode 4 than when no titanium mesh is provided on the surface of the cylindrical rotating cathode 4, the electrolysis time is significantly shortened. It can be seen that the recovery efficiency of Cu is improved.

(Experimental example 21)
Experimental Example 21 and Experimental Examples 22 to 24 to be described later use the recovery device provided with the cylindrical rotating cathode 4a shown in FIG. 4 in the metal recovery device shown in FIG. This was performed in order to examine the recovery efficiency when Au was recovered. Grooves are formed on the entire surface of the cylindrical rotating cathode 4a by cutting. The shape of the groove is regularly processed, the width x of the groove is 1 mm, the distance y between the grooves is 1 mm, and the depth z of the groove is 3 mm. The cross-sectional shape of the groove formed on the surface of the rotating cathode is rectangular, and as shown in FIG. 4, the grooves formed in the vertical direction are arranged at equal intervals in the circumferential direction.

  The experimental conditions were the same as in Experimental Example 1 above. In addition, the surface area of the cylindrical rotating cathode 4a provided with unevenness increased by 4.0 times compared to the surface area when no unevenness was provided. The increase rate of the surface area is the same as in Experimental Example 1.

  Table 6 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis.

  As is apparent from Table 6 below, when the electrolysis was performed for 3 hours, the Au concentration of the treatment liquid decreased to 1 mg / L. Au in the treatment liquid was electrodeposited on the surface of the cylindrical rotating cathode 4a.

  As is clear from Experimental Example 21 and Experimental Example 1, Au recovery efficiency is achieved when the cylindrical rotating cathode 4a having a groove with a depth of 3 mm is used on the surface and when the surface of the cylindrical rotating cathode 4 is titanium. It was the same when the nets were double coated.

(Experimental example 22)
In Experimental Example 22, the influence of the groove depth on the Au recovery efficiency was examined. Specifically, in Example 21 above, the treatment liquid was electrolyzed under the same conditions as in Example 21 except that the cylindrical rotating cathode 4a formed with a groove depth z as shallow as 1.5 mm was used. . In addition, the surface area of the cylindrical rotating cathode 4a provided with the unevenness only increased by 2.5 times compared to the surface area when the unevenness was not provided.

  Table 6 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. As apparent from Table 6 below, it took 5 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  As is apparent from the results of Experimental Example 22 and the results of Experimental Example 21, it can be seen that the Au recovery efficiency can be improved by increasing the surface area of the rotating cathode by deepening the groove.

(Experimental example 23)
In Experimental Example 23, the effect of the conductor coated on the surface of the cylindrical rotating cathode 4a on the Au recovery efficiency was examined by combining the first embodiment and the second embodiment. Specifically, on the surface of the cylindrical rotating cathode 4a (groove depth z is 1.5 mm) used in Experimental Example 22, the conductor has an average opening of 1 mm and an average wire diameter of 0.3 mm ( The treatment solution was electrolyzed under the same conditions as in Experimental Example 21 except that a 20 mesh) titanium mesh was wound in a single layer. The titanium mesh is attached by spot welding so as to be in close contact with the surface of the cylindrical rotating cathode 4a. In addition, the surface area of the cylindrical rotating cathode 4a (unevenness formation + conductor coating) used in this experimental example was increased by 3.9 times compared to the surface area when the unevenness was not formed and the conductor was not covered with the conductor.

  Table 6 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. As apparent from Table 6 below, it took 3 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  As is clear from Experimental Example 23 and Experimental Example 22 described above, even when the depth of the recess formed on the surface of the cylindrical rotating cathode is relatively shallow and 1.5 mm, if the surface is further covered with a conductor, Since the surface area is increased, it can be seen that the Au recovery efficiency improvement effect is similar to that of Experimental Example 21 in which the concave portion is formed as deep as 3.0 mm on the surface of the cylindrical rotating cathode.

(Experimental example 24)
In Experimental Example 24, the treatment liquid was electrolyzed under the same conditions as in Experimental Example 21 except that unevenness was formed on the surface of the cylindrical rotating cathode 4a by performing blasting in Experimental Example 21. For the blast treatment, alumina particles having a particle size of about 120 μm were used. The difference in height between the convex portion and the concave portion of the cylindrical rotating cathode 4a after the blasting process was about 0.01 mm at the maximum, and the distance between the concave portion and the convex portion was about 0.05 to 0.06 mm. In addition, the surface area of the cylindrical rotating cathode 4a subjected to the blasting process was increased by about 1.1 to 1.2 times as compared with the surface area when the blasting process was not performed.

  Table 6 shows the results of measuring the Au concentration of the treatment liquid every several hours after the start of electrolysis. As apparent from Table 6 below, it took 15 hours to reduce the Au concentration of the treatment liquid to 1 mg / L.

  As is clear from Experimental Example 24 and Experimental Example 21, in the blast treatment according to Experimental Example 24, the increase in surface area did not reach the desired level, so compared with Experimental Example 21 in which the surface area was increased about four times, The time required to reduce the Au concentration of the treatment liquid to 1 mg / L has increased 5 times.

(Experimental example 25)
Experimental Example 25 and Experimental Example 26 described later were performed in order to evaluate the durability of the cylindrical rotating cathode.

  In Experimental Example 25, the cylindrical rotating cathode 4a electrodeposited with Au in the Experimental Example 21 was removed from the apparatus and immersed in 10 L of heated aqua regia for 600 hours. Aqua regia was heated to 70-90 ° C. Moreover, since a part of solvent evaporates with time and the amount of aqua regia decreases, new aqua regia was added appropriately.

  After the elapse of 600 hours, the cylindrical rotating cathode 4a was taken out from aqua regia, washed with water and dried, and then the surface of the cathode was visually observed to evaluate the shape change of the surface of the cylindrical rotating cathode 4a before and after immersion. After 600 hours, almost no change was observed in the surface shape of the cylindrical rotating cathode 4a.

(Experimental example 26)
In Experimental Example 26, the cylindrical rotating cathode 4 electrodeposited with Au in Example 1 was removed from the apparatus, and the cylindrical rotating cathode 4 was immersed in aqua regia under the same conditions as in Experimental Example 25 to evaluate the shape change. did. After 600 hours, when the shape change of the surface of the cylindrical rotating cathode 4 was visually observed, a part of the titanium mesh coated on the surface of the cylindrical rotating cathode 4 was peeled off from the surface of the cylindrical rotating cathode 4. It was.

  Comparing the results of Experimental Example 26 and Experimental Example 25, the Au recovery efficiency is comparable, but the durability of the cylindrical rotating cathode can be improved by using a grooved rotating cathode instead of a Ti net. I understand.

  According to the present invention, it is an apparatus used when recovering metal from a metal-containing solution by electrolysis, and can realize space saving and reduction of equipment load, and can recover metal in a short time. An extremely excellent device can be provided.

Claims (6)

An apparatus for recovering metal by electrolyzing a metal-containing solution,
The device
A columnar or cylindrical rotating cathode that rotates about an axis; and
An anode disposed to face the rotating cathode;
A net-like or porous conductor, and
At least a part of the surface of the rotating cathode facing the anode is covered with the conductor.   The recovery device according to claim 1, wherein the metal is a noble metal.   The recovery device according to claim 1, wherein the conductor is a metal net having an average opening of 0.5 to 3 mm.   The recovery apparatus according to claim 1, wherein the conductor is a metal net having an average wire diameter of 0.3 to 0.5 mm. An apparatus for recovering metal by electrolyzing a metal-containing solution,
The device
A columnar or cylindrical rotating cathode that rotates about an axis; and
An anode arranged to face the rotating cathode;
At least a part of the surface of the rotating cathode facing the anode is processed into a concavo-convex shape.   The recovery device according to claim 5, wherein at least a part of the surface of the rotating cathode facing the anode is coated with a net-like or porous conductor.

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