Method of producing cathode

Abstract

To provide a method of producing a cathode, capable of producing a cathode using a starting sheet suitably removed of the internal stress.SOLUTION: The method of producing a cathode C comprising a starting sheet S using a cathode finishing machine 1, comprises a weight measurement step of measuring the weight of the starting sheet S to be carried into the cathode finishing machine 1, and an internal stress removal step of feeding the starting sheet S whose weight has been measured in the weight measurement step to a leveler unit 3 comprising work rollers 4 disposed above and below the cathode finishing machine 1, and bending the starting sheet S in the thickness direction while conveying the starting sheet S held between the upper and lower work rollers 4 of the leveler unit 3 to remove the internal stress of the starting sheet S. A clearance adjustment step of adjusting the gaps between the upper and lower work rollers 4 of the leveler unit 3 is carried out according to the weight of the starting sheet S measured in the weight measurement step prior to feeding of the starting sheet S whose weight has been measured in the weight measurement step to the leveler unit 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a cathode. More specifically, the present invention relates to a method for manufacturing a cathode that suppresses distortion of the cathode used in an electrolysis process such as non-ferrous metals.

Background Art

[0002] In the electrolysis process of non-ferrous metal refining, an anode (crude metal plate) and a cathode are alternately arranged in a state of being suspended in an electrolytic cell and immersed in the electrolytic solution of the electrolytic cell, and electricity is passed between the anode and the cathode in that state to electrodeposit a high-purity metal on the surface of the cathode to produce a product.

[0003] The electric power used in such an electrolysis process is greatly affected by the distance between the anode and the cathode, that is, the interval between the anode and the cathode. For example, if the interval between the anode and the cathode is narrowed, the electric resistance of the electrolytic solution can be reduced, so the electric power used in the electrolysis process can be reduced. However, if the interval between the anode and the cathode is narrowed too much, there is a possibility that the metal electrodeposited on the cathode may come into contact with the anode as electrodeposition progresses. If such contact (short circuit) occurs, current will flow directly from the anode to the cathode and the electric power will be wasted. On the other hand, if the interval between the anode and the cathode is widened, although contact between the anode and the cathode can be avoided, the electric resistance of the electrolytic solution will increase and a large amount of electric power will be required. Therefore, it is desirable to make the interval between the anode and the cathode as narrow as possible within a range where no short circuit occurs.

[0004] In addition, in the electrolysis process, a plurality of anodes and a plurality of cathodes are alternately arranged. If there is variation in the interval between the anode and the cathode, variation will occur in the current flowing between the anode and the cathode in the electrolytic cell. Then, variation will occur in the state of the metal electrodeposited on the cathode, and variation may also occur in the quality of the product. Therefore, it is necessary to make the interval between the anode and the cathode uniform.

[0005] However, if the anode or cathode has bends or twists, even when the anode and cathode are arranged so that the spacing between them is uniform, the spacing between the anode and cathode will become narrower or wider at the bent or twisted portions. Then, at the locations where the spacing becomes narrower, even if the current concentrates and the anode and cathode were not initially in contact, there is a possibility of a short circuit occurring due to the progress of electrodeposition. On the other hand, at the locations where the spacing becomes wider, there is a possibility that sufficient electrodeposition cannot occur on the cathode. Therefore, in order to make the spacing between the anode and cathode uniform, it is desirable that the anode and cathode have a shape with few bends and twists and a well - formed shape (such as flatness), that is, a shape with high verticality in the state of being suspended in the electrolytic cell.

[0006] The cathode used for metal electrolysis is manufactured by the following process using a cathode finishing machine (see Patent Documents 1 - 3).

[0007] First, a thin electrolytic copper (hereinafter referred to as the seed plate) refined in seed plate electrolysis is produced, and the produced seed plate is transported to a cathode finishing machine. The seed plate transported to the cathode finishing machine is supplied to a roller leveler having a large number of work rollers arranged in an upper and lower staggered pattern. In the roller leveler, the seed plate is repeatedly bent by being sandwiched between a large number of work rollers. Then, the internal stress of the seed plate is removed, and it is processed so that the warp and the uneven width become smaller. The seed plate processed by the roller leveler is supplied between an upper grooving roller and a lower grooving roller, and a groove - shaped deformation is applied along the leading edge to the trailing edge of the seed plate. Then, a hanging handle formed by bending a strip - shaped metal plate into a U - shape is attached to the upper part of the seed plate with the groove - shaped deformation, and the cathode is completed by inserting a cathode beam into this hanging handle.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

[0009] Here, the seed plates supplied to the cathode finishing machine are produced at a rate of 4,000 to 5,000 per day by seed plate electrolysis and stored in a dedicated container (so-called pallet) with about 100 to 150 stacked. Then, the seed plates are supplied to the cathode finishing machine (see Fig. 1(A)) in the form of pallets, and the seed plates are supplied one by one from the pallets to the cathode finishing machine. However, the seed plates have a certain variation in thickness within a certain range. For this reason, if the operation is carried out with the interval between the upper and lower work rolls of the roller leveler fixed, there is a possibility that the seed plates cannot be sufficiently corrected according to the plate thickness. For example, when the interval between the upper and lower work rolls is fixed, if the plate thickness is the same, a certain force can be applied to the seed plate to perform equivalent correction. On the other hand, when the plate thickness of the seed plate changes, the strength of the seed plate changes. Therefore, when the interval between the upper and lower work rolls is constant, there is a possibility that all the seed plates cannot be sufficiently corrected. In particular, in the case of a seed plate with a thickness thinner than other seed plates, the bending stress by the work roll becomes too small, resulting in insufficient correction of the seed plate and the problem that the internal stress cannot be sufficiently removed.

[0010] In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a cathode capable of manufacturing a cathode using a seed plate with appropriately removed internal stress.

[0011] The manufacturing method of the cathode of the first invention is a method for manufacturing a cathode having a seed plate by a cathode finishing machine, comprising a weight measurement step of measuring the weight of the seed plate carried into the cathode finishing machine, a clearance adjustment step of adjusting the clearance between the work rollers disposed above and below the leveling part of the cathode finishing machine based on the weight of the seed plate measured in the weight measurement step, and an internal stress removal step of removing the internal stress of the seed plate while conveying the seed plate sandwiched between the work rollers above and below the leveling part of the cathode finishing machine. The manufacturing method of the cathode of the second invention is, in the first invention, in the weight measurement step, measuring the total weight which is the weight of a plurality of the seed plates, calculating the weight per seed plate using the total weight measured in the weight measurement step, setting the clearance between the work rollers above and below the leveling part which is set when the preset reference weight is equal to the weight per seed plate as the reference clearance, and in the clearance adjustment step, when the calculated weight per seed plate is heavier than the reference weight, widening the clearance between the work rollers above and below the leveling part by the clearance adjustment part of the leveling part to be wider than the reference clearance, and when the calculated weight per seed plate is lighter than the reference weight, narrowing the clearance between the work rollers above and below the leveling part by the clearance adjustment part of the leveling part to be narrower than the reference clearance. The manufacturing method of the cathode of the third invention is, in the first invention, in the weight measurement step, measuring the total weight which is the weight of a plurality of the seed plates, calculating the weight per seed plate using the total weight measured in the weight measurement step, and in the clearance adjustment step, adjusting the clearance between the work rollers above and below the leveling part according to the calculated weight per seed plate based on the relationship between the weight per seed plate resulting in a predetermined cathode strain and the clearance between the work rollers above and below the leveling part. The manufacturing method of the cathode of the fourth invention is, in the third invention, characterized by adjusting the clearance on the side where the seed plate is supplied in the work rollers above and below the leveling part based on the following polynomial curve. y = -0.30×x2 +4.94×x - 21.38 y: Gap between work rollers x: Calculated weight per seed plate

Advantages of the Invention

[0012] Since the gap is adjusted according to the weight of the seed plate, a cathode using a seed plate with appropriately removed internal stress can be manufactured.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0014] The method for manufacturing a cathode according to the present embodiment is a method for manufacturing a cathode provided with a seed plate by a cathode finishing machine, and is characterized in that the distortion of the cathode can be suppressed based on the weight of the seed plate.

[0015] The method for manufacturing a cathode according to the present embodiment is suitable for preventing deformation of a cathode used in the production of electrolytically refined electrolytic copper, but the cathode manufactured by the method for manufacturing a cathode according to the present embodiment is not limited to such a cathode. For example, the manufacturing method of the cathode of the present embodiment can be used for manufacturing a cathode that requires prevention of deformation, such as a cathode used for manufacturing electrolytic nickel by electrolytic nickel refining.

[0016] <Cathode C> The outline of the cathode C produced by the manufacturing method of the cathode of the present embodiment will be described. As shown in FIG. 3, the cathode C is obtained by suspending the seed plate S from the cathode beam B with the suspension handle sh. The seed plate S is, for example, a metal plate with a vertical width of about 1000 to 1150 mm, a horizontal width of about 1000 to 1150 mm, and a thickness of about 0.5 to 1.0 mm. When used for manufacturing electrolytic copper, electrolytic copper with a purity of 99.99% is used for the seed plate S.

[0017] In the cathode finishing machine 1 described later, a container P (hereinafter referred to as the seed plate pallet P. See FIG. 1) in which a plurality of seed plates S obtained from an electrolysis process of the seed plate (hereinafter referred to as the seed plate electrolysis process) not shown are stacked and accommodated is transferred to the supply port of the cathode finishing machine 1 described later, and finally, the cathode C with the suspension handle sh and the cathode beam B attached to the seed plate S is manufactured.

[0018] Here, the seed plate electrolysis process means, for example, a process of obtaining a seed plate of electrolytic copper with a purity of 99.99% when manufacturing electrolytic copper. For example, in the electrolytic refining of copper, the crude copper obtained in the copper smelting process is used as the anode, and a thin seed plate of electrolytic copper with a thickness of about 0.6 mm is used as the cathode for electrolysis. Copper is electrodeposited on the electrodeposited surface of this thin seed plate to refine electrolytic copper, and the seed plate S is also manufactured by the same electrolysis process as this electrolytic copper. In this seed plate electrolysis process, an anode (positive electrode) made of crude copper with a purity of about 98% and a mother plate (negative electrode) made of stainless steel or titanium are alternately immersed in an electrolytic cell filled with an electrolytic solution. In this state, while supplying the electrolytic solution to the electrolytic cell, for example, a current density of 250 A / m 2A current is supplied between the two electrodes to such an extent. Then, copper is deposited on the electroplating surface of the mother board. After energization, if the deposited copper on the electroplating surface of the mother board is peeled off from the mother board, a seed plate of electrolytic copper with a purity of 99.99% can be obtained. The electrolytic solution used in this seed plate electrolysis process is not particularly limited, but for example, a sulfuric acid solution of copper sulfate added with glue, abitone, etc. is preferable.

[0019] On the seed plate S of the cathode C, a plurality of grooves extending along its vertical direction (the direction that becomes the vertical direction when the cathode C is suspended, the vertical direction in FIG. 3. Hereinafter, when simply referring to the vertical direction, this direction may be meant.) are formed. These plurality of grooves are formed by the cathode finishing machine 1 described below. By forming these plurality of grooves, the unevenness and bending of the seed plate S in the vertical direction of the seed plate S of the cathode C are reduced, and cathode distortion can be suppressed. For this reason, if the cathode C with a plurality of grooves formed is used, it becomes easier to make the distance between the anode and the cathode uniform when immersed in the electrolytic cell, and the consumption of the amount of electric power in the energization process can be suppressed, so the production efficiency of electrolytic purification can be improved.

[0020] In addition, in this specification, cathode distortion means the thickness in the depth direction which is the direction orthogonal to the vertical direction and the width direction in the cathode C, that is, the distance in the front-back direction of the seed plate S in the cathode C (see X in FIG. 3). For example, when the cathode C is placed on a flat floor with the back surface (the right surface in FIG. 3) facing down (that is, when placed so that the back surface contacts the surface of the flat floor), the cathode distortion can be grasped by the distance (vertical height) from the surface of the floor to the part farthest from the surface of the floor on the back surface side (the lower right end of the seed plate S in FIG. 3).

[0021] <Cathode Finishing Machine 1> Next, an example of the cathode finishing machine 1 for creating the above-described cathode C will be described according to the method for manufacturing a cathode of this embodiment.

[0022] As shown in FIG. 1(A), the cathode finishing machine 1 includes an internal stress removing unit 2, a grooving unit 10, a handle forming unit, and a cathode beam mounting unit, similar to a general cathode finishing machine. Further, the cathode finishing machine 1 includes a seed plate supply unit D that supplies a seed plate pallet P on which a plurality of seed plates S are stacked and supplies the seed plate S to the internal stress removing unit 2.

[0023] In FIG. 1(A), the description of the handle forming unit for attaching the handle sh to the seed plate S and the cathode beam mounting unit for attaching the cathode beam B to the handle sh is omitted. In addition to the above functions, the cathode finishing machine 1 may have a thickness measuring unit that measures the thickness of the seed plate S supplied to the internal stress removing unit 2. Furthermore, when the cathode finishing machine 1 has an internal stress removing unit 2, the grooving unit 10 does not necessarily have to be provided.

[0024] <Seed plate supply unit D> The seed plate supply unit D has a function of sequentially supplying the seed plate S to the internal stress removing unit 2. In the cathode finishing machine 1 used in the manufacturing method of the cathode of the present embodiment, since a plurality of seed plates S are supplied in a stacked state on the pallet P, the seed plate supply unit D has a function of sequentially supplying the seed plate S from the pallet P to the internal stress removing unit 2. Note that the method of supplying the seed plate S on the pallet P to the internal stress removing unit 2 in the seed plate supply unit D is not particularly limited. For example, a method of feeding out the seed plates S one by one from the pallet P by a pusher or the like on a table that conveys the seed plate S toward the internal stress removing unit 2, or a method of holding the seed plates S on the pallet P and transferring them onto the table can be adopted.

[0025] <Internal stress removing unit 2> The internal stress removal unit 2 has a function of removing the internal stress of the seed plate S by sandwiching the seed plate S with rollers. Specifically, the internal stress removal unit 2 includes a leveller unit 3 that applies an appropriate force to the seed plate S by sandwiching the seed plate S with rollers, and a clearance adjustment unit that adjusts the clearance in the vertical direction of the leveller unit 3. This clearance adjustment unit has a function of adjusting the clearance in the vertical direction of the leveller unit 3 based on the weight of the seed plate S supplied to the internal stress removal unit 2 as described later. In this internal stress removal unit 2, the "internal stress removal process" referred to in the claims is performed, and in the clearance adjustment unit of the internal stress removal unit 2, the "clearance adjustment process" referred to in the claims is performed. Hereinafter, the configuration of the internal stress removal unit 2 will be described in order.

[0026] <Leveller unit 3> As shown in FIG. 1(B), the leveller unit 3 includes a plurality of work rollers 4 that come into direct contact with the seed plate S. Specifically, the leveller unit 3 has an upper roller group 3A and a lower roller group 3B, and each roller group 3A, 3B has a plurality of work rollers 4 arranged along the conveyance direction of the seed plate S. For example, as shown in FIG. 1(B), in the roller groups 3A, 3B, the rotation axes of the work rollers 4 of each roller group 3A, 3B are parallel to each other along the conveyance direction of the seed plate S, and the work rollers 4 of the roller group 3A and the work rollers 4 of the roller group 3A are arranged with a predetermined interval (gap) in the vertical direction. That is, the lines connecting the rotation axes of the upper and lower work rollers 4 provided at corresponding positions in the conveyance direction are arranged substantially orthogonal to the conveyance direction of the seed plate S. In other words, the corresponding upper and lower work rollers 4 are arranged such that the positions in the conveyance direction of the seed plate S are the same in order from the entrance side in the conveyance direction. Note that the work rollers 4 of the roller group 3A and the work rollers 4 of the roller group 3A may be arranged in a staggered pattern along the conveyance direction of the seed plate S. This staggered arrangement means a state in which the positions of the corresponding upper and lower work rollers 4 in the conveyance direction of the seed plate S are shifted.

[0027] In addition, as shown in FIG. 1(B), the leveler section 3 may have a structure in which the upper roller group 3A includes a backup roller 5 that supports the work roller 4 above the work roller 4. The backup roller 5 is provided such that its rotation axis is parallel to the rotation axis of the work roller 4 and its surface contacts the surface of the work roller 4. Similarly, the lower roller group 3B may have a structure in which a backup roller 5 that supports the work roller 4 is provided below the work roller 4. The backup roller 5 is provided such that its rotation axis is parallel to the rotation axis of the work roller 4 and its surface contacts the surface of the work roller 4.

[0028] Since the internal stress removing section 2 has the above-described leveler section 3, the warp and unevenness width of the seed plate S can be reduced. That is, when the seed plate S is fed between the work roller 4 of the upper roller group 3A, the work roller 4 of the lower roller group 3B, the warp and unevenness width of the seed plate S in the conveyance direction can be reduced because the seed plate S is repeatedly bent in the plate thickness direction by the multiple work rollers 4. Further, since the surface of the work roller 4 is in surface contact with the surface of the seed plate S, the seed plate S is also straightened in the direction perpendicular to the conveyance direction. Note that the seed plate S is supplied to the internal stress removing section 2 such that the vertical direction thereof coincides with the conveyance direction of the seed plate S in the leveler section 3 of the internal stress removing section 2.

[0029] In addition, the leveler section 3 may have a structure in which the same pressure is applied from the upper and lower roller groups 3A and 3B to the seed plate S that has been conveyed in the conveyance direction from the side (entrance side) where the seed plate S is supplied to the leveler section 3 to the side (exit side) where the seed plate S is discharged from the leveler section 3. Further, the leveler section 3 may have a structure in which the pressure applied to the seed plate S on the exit side in the conveyance direction of the seed plate S can be set to be lower than the pressure applied to the seed plate S on the entrance side. In particular, with the latter structure, there is an advantage that a cathode having a shape close to flat can be obtained because the bending of the seed plate is reduced on the exit side.

[0030] <Clearance Adjustment Unit> The clearance adjustment unit has a function of adjusting the clearance of the leveler unit 3 (that is, the gap between the upper and lower work rollers 4, 4 in the vertical direction) based on the weight per seed plate in the pallet supplied to the cathode finisher 1. Specifically, when the total weight of the pallet becomes the reference total weight, that is, when the average weight of a plurality of seed plates S stacked on the pallet P (hereinafter sometimes simply referred to as the weight per seed plate) becomes the reference weight, the clearance adjustment unit is based on the difference between the weight per seed plate and the reference weight. It has a function of adjusting the gap between the upper and lower work rollers (hereinafter sometimes referred to as clearance). Specifically, when the weight per seed plate is heavier than the reference weight, the clearance adjustment unit widens the clearance more than the reference clearance, and when the weight per seed plate is lighter than the reference weight, the clearance adjustment unit narrows the clearance more than the reference clearance. The reference clearance here means the gap between the upper and lower work rollers at which appropriate correction can be performed on the seed plate S when the weight per seed plate is the reference weight.

[0031] Here, the reference weight means the weight per seed plate manufactured from the electrolytic cell when ideal seed plate electrolysis is performed in the electrolytic cell for performing seed plate electrolysis for manufacturing the seed plate S. When manufacturing the seed plate S by the electrolytic cell, for example, 1m 2In the case of a square seed plate, it is known that electroplating until the thickness reaches the equivalent of 6 to 10 kg, more preferably 7 to 8 kg, is easy to handle, and the seed plate is manufactured to achieve such a state. However, even when the seed plate S is manufactured in the same electrolytic cell to achieve the state described above, the total weight of the manufactured seed plate S varies depending on the energization time and the amount of electricity in coulombs that has flowed. Since this change in the total weight of the seed plate S is due to the state of the manufactured seed plate S, the difference between the total weight of the seed plate S and the reference total weight, in other words, the difference between the weight per seed plate and the reference weight, indicates differences in properties such as the thickness of the seed plate. When stacking and transporting seed plates manufactured in the same electrolytic cell on a pallet P, based on the difference between the weight per seed plate obtained from the total pallet weight and the reference weight, taking the clearance at which appropriate correction can be performed on the seed plate S as the reference clearance and adjusting the clearance based on the deviation between the weight per seed plate and the reference weight, it is possible to simply and appropriately bring the internal stress of the seed plate S into an appropriate state of removal.

[0032] For example, on a day when many 7.5 kg seed plates S are obtained, set the reference weight to 7.5 kg and adjust the clearance of the leveling part 3 so as to be suitable for the 7.5 kg seed plate S. Then, the correction of the seed plate S by the leveling part 3 can be particularly suitably performed for the seed plate S with a weight of 7.5 kg. On the other hand, for a seed plate S whose weight deviates from 7.5 kg, there is a possibility that the correction of the seed plate S cannot be suitably performed. Therefore, by adjusting the clearance based on the deviation from 7.5 kg (reference weight) of the weight per seed plate obtained from the total pallet weight, even for a seed plate S whose weight deviates from 7.5 kg, the correction of the seed plate S can be suitably performed.

[0033] In addition, in the above example, the case where the clearance adjustment part automatically adjusts the clearance when the weight per seed plate is supplied to the clearance adjustment part has been described, but the clearance can also be manually adjusted by an operator operating the clearance adjustment part.

[0034] <Grooved part 10> The grooving section 10 forms grooves (not shown) in the base plate S from which internal stress has been removed by the internal stress removal section 2. Specifically, while transporting the base plate S, a plurality of grooves parallel to the transport direction of the base plate S in the internal stress removal section 2, that is, parallel to the vertical direction of the base plate S, are formed in the base plate S. As shown in Fig. 2(A), this grooving section 10 is provided with a plurality of grooving roller pairs 11 to 13. Each of these three pairs of grooving roller pairs 11 to 13 is provided with one upper and one lower grooving roller 11A to 13B (see Fig. 2(B)).

[0035] As shown in Figs. 2(A) and (B), the grooving rollers 11A to 13B of each grooving roller pair 11 to 13 are provided with flange portions 15 to 17 at predetermined positions in the axial direction. Although the positions where the flange portions 15 to 17 are provided are different for each grooving roller pair 11 to 13, they are provided at the same position for the paired grooving rollers (for example, grooving rollers 11A, 11B) (see Fig. 2(B)). Also, for the paired grooving rollers 11A to 13B, a valley flange portion is provided on one side and a peak flange portion is provided on the other side (see Fig. 2(B)). For this reason, when the base plate S is passed between the paired grooving rollers 11A to 13B, grooves that are recessed toward the valley flange portion side are formed in the base plate S at the portions sandwiched by the flange portions 15 to 17. For example, when the flange portions 15 to 17 are provided as shown in Fig. 2(A), first, three grooves are formed in the central portion in the width direction of the base plate S by the flange portions 15a, 15b of the grooving rollers 11A, 11B that first form grooves in the base plate S. Next, a total of four grooves g, two on each outer side of the grooves formed by the grooving rollers 11A, 11B, are formed by the flange portions 16a, 16b of the grooving rollers 12A, 12B. And finally, a total of four grooves, two on each further outer side of the grooves formed by the grooving rollers 13A, 13B, are formed by the flange portions 17a, 17b of the grooving rollers 13A, 13B that finally form grooves in the base plate S.

[0036] <Hanging handle forming section> The hanging handle forming section attaches the hanging handle sh to the base plate S grooved by the grooving section 10. Specifically, when the seed plate S is supplied from the grooved portion 10, both ends of the strip-shaped plate processed to a predetermined size (for example, approximately 100 mm in length × approximately 300 mm in width) of the metal plate are fixed to both surfaces of the seed plate S, and the ring-shaped hanging handle sh is formed. When attaching a pair of hanging handles sh, sh, they are attached at positions as shown in FIG. 3.

[0037] <Cathode beam attachment portion> The cathode beam attachment portion is for attaching the cathode beam B to the hanging handle sh. Specifically, the cathode beam B is inserted through the ring-shaped hanging handle sh (for example, a pair of hanging handles sh, sh). In this way, when the cathode beam B is attached to the hanging handle sh, the cathode C is completed (see FIG. 3).

[0038] <Manufacturing method of the cathode of this embodiment> In the cathode finishing machine 1 as described above, the cathode C can be manufactured as follows.

[0039] First, before being carried into the cathode finishing machine 1, an operation of stacking a plurality of seed plates S on the pallet P is performed. At this time, the weight of the pallet P, that is, the weight of the pallet P including the stacked seed plates S is measured (weight measurement step). Then, when a predetermined number of seed plates S are stacked, on the seed plate S located at the top, the measured total weight of the seed plates S, that is, the weight obtained by subtracting the weight of the pallet P alone from the weight of the pallet P including the stacked seed plates S is engraved. Also, the number of the stacked seed plates S is engraved together. When the number of the seed plates S to be stacked is constant, only the total weight of the seed plates S may be engraved.

[0040] Next, when the pallet P on which a plurality of seed plates S are stacked is carried into the seed plate supply unit D of the cathode finishing machine 1, the operator calculates the weight per seed plate based on the number of the seed plates S and the total weight of the seed plates S engraved on the seed plate S, and supplies the calculated weight per seed plate of the seed plates S to the clearance adjustment unit of the internal stress removal unit 2.

[0041] When the weight per seed plate is supplied to the clearance adjustment unit, the clearance adjustment unit compares the supplied weight per seed plate with the reference weight and adjusts the clearance (clearance adjustment step). That is, when the weight per seed plate is heavier than the reference weight, the clearance is made larger than the reference gap, and when the weight per seed plate is lighter than the reference weight, the clearance is made smaller than the reference gap. Also, when the weight per seed plate is approximately the same as the reference weight, the clearance is set as the reference gap.

[0042] As described above, when the clearance is adjusted, the seed plates S are sequentially supplied from the seed plate supply unit D to the internal stress removal unit 2, and the seed plates S are corrected. The seed plates S corrected by the internal stress removal unit 2 are supplied to the grooving unit 10 (internal stress removal step).

[0043] Also, the seed plate S supplied to the grooving unit 10 is grooved by the grooving unit 10 and supplied to the handle forming unit.

[0044] Then, the seed plate S supplied to the handle forming unit has the handle sh attached in the handle forming unit and is then supplied to the cathode beam attachment unit. When the cathode beam B is attached to the handle sh in the cathode beam attachment unit, the cathode C is manufactured.

[0045] If the cathode C is manufactured by the method as described above, a cathode using the seed plate S with the internal stress appropriately removed can be manufactured. Then, a cathode C having a shape with less bending and twisting and a well - formed shape (such as flatness), that is, a shape with high verticality in the state of being suspended in the electrolytic cell can be manufactured.

[0046] <Regarding the clearance adjustment in the clearance adjustment step> As described above, in the clearance adjustment unit, the clearance of the leveler unit 3 is adjusted based on the difference between the weight per seed plate loaded on the pallet P supplied to the cathode finisher 1 and the reference weight. Regarding the adjustment amount of this clearance, that is, how much the clearance is changed from the reference gap, various methods can be adopted.

[0047] For example, in advance, in a preliminary test or preliminary operation, the difference between the weight per seed plate and the reference weight is made constant, and the cathode distortion X is measured by changing the clearance in that state. Then, the clearance that results in a predetermined cathode distortion X under this condition (the difference between the weight per seed plate and the reference weight) is obtained. Then, if the difference between the weight per seed plate and the reference weight can be grasped, by adjusting to the appropriate clearance obtained in the preliminary test or preliminary operation (that is, the clearance that results in a predetermined cathode distortion X), a seed plate S with a predetermined cathode distortion X can be manufactured.

[0048] Alternatively, the clearance may be adjusted based on a relational expression between the clearance obtained in advance in a preliminary test or preliminary operation and the weight per seed plate. That is, under conditions where the weight per seed plate is different, the clearance is changed respectively to obtain the clearance that results in a predetermined cathode distortion X. Then, from the results, a relational expression between the clearance and the weights of a plurality of seed plates per sheet is calculated, and the clearance may be adjusted based on that relational expression.

[0049] For example, as shown in FIG. 4, the weight per seed plate and the clearance on the inlet side of the leveler that results in a predetermined cathode distortion X at that weight are plotted on a graph, and an approximate polynomial is calculated. Then, based on the approximate polynomial, the clearance on the inlet side of the leveler can be determined from the weight per seed plate. If a graph as shown in FIG. 4 is obtained, when the weight per seed plate is between 7.1 kg and 8.3 kg, the following formula 1 can be used as the approximate polynomial for calculating the clearance on the inlet side of the leveler from the weight per seed plate. Formula 1 y = -0.30×x2 +4.94×x - 21.38 y: Clearance of the work roller (mm) x: Weight per seed plate (kg)

[0050] <Regarding Clearance> Clearance refers to the gap between the work rollers 4 of the upper roller group 3A and the work rollers 4 of the lower roller group 3B of the leveler section 3 (the gap between the upper and lower work rollers 4). The gap between the upper and lower work rollers 4 means the distance between the first contact surface where the work roller 4 of the upper roller group 3A contacts the seed plate S and the second contact surface where the work roller 4 of the lower roller group 3B contacts the seed plate S. And the aforementioned first contact surface refers to the surface formed by connecting the points where two or more adjacent work rollers 4 of the roller group 3A contact the seed plate S. Also, the aforementioned second contact surface refers to the surface formed by connecting the points where two or more adjacent work rollers 4 of the roller group 3B contact the seed plate S.

[0051] For example, as shown in Fig. 1(B), when the work rollers 4 of the roller groups 3A and 3B are arranged with a predetermined gap in the vertical direction along the conveying direction of the seed plate S, at the upper and lower work rollers 4 arranged at the same position in the conveying direction of the seed plate S (for example, the upper work roller 4 and the lower work roller 4 arranged on the leftmost side in Fig. 1(B)), the first contact surface includes the contact point where the upper work roller 4 contacts the seed plate S, and the second contact surface includes the contact point where the lower work roller 4 contacts the seed plate S. Therefore, the shortest distance between the two is the gap between the upper and lower work rollers 4. In other words, when the work rollers 4 of the roller groups 3A and 3B are arranged with a predetermined gap in the vertical direction along the conveying direction of the seed plate S, the shortest distance between the surfaces of the upper and lower work rollers 4 is the gap between the upper and lower work rollers 4. Also, when the work rollers 4 of the roller groups 3A and 3B are arranged in a staggered pattern, similarly, the first contact surface includes the point where the upper work roll 4 and the seed plate S come into contact, and the second contact surface includes the point where the lower work roller 4 and the seed plate S come into contact. Therefore, the shortest distance between the two becomes the gap between the upper and lower work rollers 4.

[0052] In addition, in the method for manufacturing the cathode of the present embodiment, the location for adjusting the gap between the upper and lower work rollers 4 is not particularly limited. For example, if the gap between the upper and lower work rollers 4 of a predetermined upper and lower work rollers 4 among the work rollers 4 of the roller groups 3A and 3B of the leveler section 3 is adjusted, and the structure is such that the other upper and lower work rollers 4 are set to follow this gap, then it is only necessary to adjust the gap between the predetermined upper and lower work rollers 4. On the other hand, in the case of the leveler section 3 having a pressure reduction and involute type structure that can be set so that the pressure applied to the seed plate S on the outlet side in the conveyance direction of the seed plate S is lower than the pressure applied to the seed plate S on the inlet side, among the upper and lower work rollers 4, it is preferable to adjust the gap between the upper and lower work rollers 4 located on the inlet side where the most pressure is applied (in FIG. 1(B), the upper and lower work rollers 4 located on the leftmost side) in the above-described manner. By adjusting the gap between the upper and lower work rollers 4 at such a location, the advantage of being able to more appropriately remove the internal stress of the seed plate S can be obtained.

[0053] <When measuring the weight of each individual seed plate S> In the above example, in the clearance adjustment, the case where the clearance adjustment is performed based on the weight per seed plate of the plurality of seed plates S carried in while stacked on the pallet P, in other words, the average weight of the plurality of seed plates S, was explained. On the other hand, clearance adjustment may be performed using the weight of each individually measured seed plate S, or the weight of a specific seed plate S extracted from a plurality of seed plates S (or the average weight of several specific seed plates S extracted from a plurality of seed plates S). That is, when the weight of the individually measured seed plate S or the like is greater than the reference weight, the clearance may be made larger than the reference gap, and when the weight of the individually measured seed plate S or the like is smaller than the reference weight, the clearance may be made smaller than the reference gap. Further, the clearance may be adjusted based on the weight of each individually measured seed plate S obtained in advance in a preliminary test or a preliminary operation, or a relational expression between the weight of each individually measured seed plate S and the clearance may be calculated, and the clearance may be adjusted based on the relational expression.

Example

[0054] It was confirmed that by using the method for manufacturing a cathode of the present invention, fluctuations in the distortion of the produced cathode can be suppressed, and the distortion of the cathode can be maintained at an appropriate value for a long period of time.

[0055] In the example, using a cathode finishing machine having the structure shown in Fig. 1(A), based on the weight per seed plate, the gap (clearance) between the upper and lower work rollers located on the inlet side of the leveler was adjusted, and cathodes were produced for 92 days under the condition of 2,400 pieces per day, and the average distortion of the cathodes during the entire operation period was confirmed. The weight per seed plate used for clearance adjustment was obtained by dividing the total weight of the seed plates in a pallet (corresponding to the seed plate pallet in the present embodiment) on which the seed plates were loaded by the total number of seed plates. Further, the clearance adjustment based on the weight per seed plate was performed based on the above-described formula 1. The clearance during the above period varied within a range of -0.8 mm to -1.5 mm with respect to the reference gap (0.78 mm).

[0056] In the comparative example, cathodes were manufactured under the same conditions as in the example except that the gap between the upper and lower work rollers in the leveler was fixed at the reference gap (0.78 mm), and the average distortion of the cathodes during the entire operation period was confirmed.

[0057] The seed plate used for manufacturing the cathode was electrolytic copper with a purity of 99.99%, having dimensions of 1050 mm in length × 1070 mm in width and a thickness of 0.6 to 1.0 mm. Also, the cathode hanger was a plate formed of electrolytic copper with a purity of 99.99%, having a strip shape with dimensions of 300 mm in length × 100 mm in width and a thickness of 0.6 to 1.0 mm. In addition, in the cathode finishing machine, grooving was also performed using a grooving roller, and the reference gap of the grooving roller (corresponding to CL in Fig. 2(B).) was set to 0.78 mm.

[0058] Comparing the average distortion of the cathode during the entire operation period of the example with the average distortion of the cathode during the entire operation period of the comparative example, the average distortion of the cathode in the example was 9.4 mm, and the average distortion of the cathode in the comparative example was 8.6 mm. That is, it was confirmed that in the example, the average distortion of the cathode during the entire operation period could be reduced by 0.8 mm compared to the comparative example.

[0059] From the above experimental results, it was confirmed that by adopting the method for manufacturing a cathode of the present invention, the average distortion of the cathode during the operation period can be reduced.

Industrial Applicability

[0060] The method for manufacturing a cathode of the present invention is suitable as a method for manufacturing a cathode using an apparatus for producing a cathode from a thin flat seed plate such as copper or nickel.

Explanation of Signs

[0061] 1 Cathode finishing machine 2 Internal stress removal section 3 Leveling section 4 Work roller 10 Grooving section C Cathode P Seed plate pallet S Seed plate X Cathode distortion

Claims

1. A method for manufacturing a cathode having a seed plate by a cathode finishing machine, comprising: a weight measurement step of measuring the weight of the seed plate before being carried into the cathode finishing machine; a clearance adjustment step of adjusting the clearance between the work rollers disposed above and below the leveler part of the cathode finishing machine based on the weight of the seed plate measured in the weight measurement step; an internal stress removal step of removing the internal stress of the seed plate while conveying the seed plate sandwiched between the work rollers above and below the leveler part of the cathode finishing machine. A method for manufacturing a cathode, characterized by the above.

2. In the weight measurement step, the total weight of a plurality of the seed plates is measured, the weight per seed plate is calculated using the total weight measured in the weight measurement step, the clearance between the work rollers above and below the leveler part set when a preset reference weight is equal to the weight per seed plate is defined as the reference clearance, in the clearance adjustment step, when the calculated weight per seed plate is heavier than the reference weight, the clearance between the work rollers above and below the leveler part is widened by the clearance adjustment part of the leveler part beyond the reference clearance; when the calculated weight per seed plate is lighter than the reference weight, the clearance between the work rollers above and below the leveler part is narrowed by the clearance adjustment part of the leveler part beyond the reference clearance. The method for manufacturing a cathode according to claim 1, characterized by the above.

3. In the weight measurement step, the total weight of a plurality of the seed plates is measured, the weight per seed plate is calculated using the total weight measured in the weight measurement step, in the clearance adjustment step, the clearance between the work rollers above and below the leveler part is adjusted according to the calculated weight per seed plate based on the relationship between the weight per seed plate that results in a predetermined cathode distortion and the clearance between the work rollers above and below the leveler part. The method for manufacturing a cathode according to claim 1, characterized by the above.

4. Adjusting the clearance on the side where the seed plate is supplied between the work rollers above and below the leveler part based on the following polynomial curve. The method for manufacturing a cathode according to claim 3, characterized by the above. y = -0.30 × x ２ + 4.94 × x - 21.38 y: Clearance of the work roller x: Calculated weight per seed plate

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