JP2014214352A - Stainless base sheet and method of producing starting sheet for copper electrolytic refining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stainless base sheet which does not cause natural peeling during electrodeposition or breaking or wrinkling during stripping after electrodeposition, reduces the frequency of re-grinding, and has a long lifetime, and a method of producing a starting sheet for copper electrolytic refining using the stainless base sheet.SOLUTION: A stainless base sheet 1 is used in production of a starting sheet for copper electrolytic refining includes, in an electrolysis surface 1a, a plurality of polishing marks in a direction nearly perpendicular to the vertical direction when suspended in an electrolytic tank, and has a surface roughness of the electrolytic surface 1a of 3.0 μm or more and 5.0 μm or less in terms of the average of ten-point average roughness (Rz) in nine regions formed by dividing one side of the electrolytic surface 1a and the other sides perpendicular to the one side into three equal parts. A release agent is applied to the electrolytic surface 1a.

Description

  The present invention relates to a stainless steel mother plate used when producing a seed plate for electrolytic purification of copper, and a method for producing a seed plate for copper electrolytic purification using the stainless steel mother plate.

  In the electrolytic refining of copper, electrolysis is performed using crude copper obtained in the copper smelting process as an anode and a thin electrocopper seed plate having a thickness of about 0.6 mm as a cathode, and copper is applied to the electrodeposition surface of the thin seed plate. The electrolytic copper is refined by putting it on. In addition, the seed plate used for electrolytic purification of copper is also produced by electrolytic purification in the same way as electrolytic copper. The anode at that time is crude copper as described above, but the cathode is made of copper such as titanium or stainless steel. Different metals are used as the mother board.

  Specifically, when producing an electrolytic copper seed plate for copper electrolytic refining, copper is electrodeposited on a cathode base plate to a thickness of about 0.6 mm using crude copper as an anode, and then the copper is peeled off. A seed plate is made. If the electrodeposition force between the mother plate and the seed plate is too high at the time of peeling, the thin seed plate is broken or wrinkled. On the other hand, if the electrodeposition force is too low, the seed plate will spontaneously peel from the mother plate during electrodeposition. The electrodeposition force of the seed plate and the mother plate varies depending on the surface state of the mother plate, and the surface roughness is most influenced by the surface state.

  As a kind of mother board, titanium and stainless steel are generally used in many cases. The titanium base plate has good corrosion resistance, and there is little change in the surface roughness of the electrodeposited surface even if it is continuously used. However, since it is expensive, there is a problem that the production cost increases. On the other hand, stainless steel base plates have come to be widely used because they are inexpensive, but they are not as corrosion-resistant as titanium, and it is difficult to manage the surface roughness of the electrodeposition surface. However, there is a problem that the seed plate is naturally peeled off or the seed plate is torn or wrinkled at the time of peeling.

  In order to eliminate such natural peeling and facilitate the peeling of the seed plate after electrodeposition, Patent Document 1 discloses a copper seed plate electrolysis in order to solve such a problem in the stainless steel copper electrolytic purification seed plate. As a stainless steel base plate, it has a surface roughness with a center line average roughness (Ra) of 0.15-0.6 μm and a ten-point average roughness (Rz) of 0.7-2.5 μm, and a fine turtle-shaped pattern. It has been proposed to use a cold-rolled stainless steel plate.

  Further, Patent Document 2 discloses a stainless steel mother whose main surface (electrodeposition surface) is substantially rectangular in order to prevent natural separation of the seed plate during electrodeposition and to ensure the peelability of the seed plate after electrodeposition. It is described that the surface roughness obtained by averaging the ten-point average roughness (Rz) of each region obtained by dividing the electrodeposited surface of the plate into nine equal parts is 3.0 μm or more.

  According to the method described in Patent Document 1 or Patent Document 2 described above, it is possible to prevent natural peeling of the seed plate and to improve the peelability of the seed plate after electrodeposition to some extent. Since it cannot be said, further improvement is required.

Japanese Patent Laid-Open No. 06-346269 JP 2011-032564 A

  As described above, in the production of a seed plate for copper electrolytic purification, if the electrodeposition force between the seed plate and the stainless steel mother plate is low, the seed plate is easily peeled off naturally from the stainless steel mother plate during electrodeposition. When the electrodeposition power of the stainless steel base plate was high, the seed plate was easily torn or wrinkled during peeling. However, there has been no stainless steel base plate that can withstand repeated use without causing the seed plate to be broken or wrinkled during such natural peeling and peeling of the seed plate.

  In addition, when the seed plate is electrodeposited and peeled off, the surface of the stainless steel mother board increases in surface roughness due to corrosion by the electrolyte and defects due to peeling off the seed board, so the mother board is used repeatedly. Along with this, it was difficult to peel off the seed plate. In such a case, in order to recover the peelability of the seed plate, the surface of the stainless steel base plate must be re-polished frequently, resulting in an increase in the number of polishing steps, and deterioration due to polishing. There was a problem that the life of the mother board was shortened.

  The present invention solves such a conventional problem, and in addition to natural peeling at the time of electrodeposition and tearing or wrinkling at the time of peeling off the seed plate after electrodeposition, the frequency of re-polishing the surface is low. An object of the present invention is to provide a stainless steel base plate having a long life and a method for producing a seed plate for copper electrolytic purification using the stainless steel base plate.

  As a result of intensive studies on the above-described conventional problems, the inventors did not experience spontaneous peeling of the seed plate during electrodeposition and had excellent peelability of the seed plate after electrodeposition, Even if the stainless steel base plate has the same surface roughness, the polishing direction of the electrodeposition surface is set to a direction substantially perpendicular to the vertical direction when suspended in the electrolytic cell during electrodeposition, and a release agent is applied to the electrodeposition surface. Sometimes, it has been found that the peelability of the seed plate after electrodeposition is further improved.

  Based on this knowledge, further investigations were conducted, and when a release agent was applied to the electrodeposition surface of the stainless steel mother board, the applied release agent flowed along the hairline-shaped polishing scratches caused by polishing. When the polishing direction is set to a direction substantially perpendicular to the vertical direction when hung from the electrolytic cell during electrodeposition, the release agent is held by the grooves in the lateral polishing scratches, so that the release agent does not sag drastically. It has been found that the amount of release agent remaining on the contact surface is increased, and therefore the peelability of the seed plate after electrodeposition is improved, leading to the present invention.

  That is, the stainless steel base plate provided by the present invention is a stainless steel base plate having a substantially rectangular electrodeposition surface used for the production of a copper electrorefining seed plate, and is hung on the surface of the electrodeposition surface in an electrolytic cell. 10-point average roughness (Rz) in 9 regions having a plurality of polishing flaws in a direction substantially perpendicular to the vertical direction of the electrode and dividing one side of the electrodeposition surface and the other side perpendicular to the one side into three equal parts. The average surface roughness of the electrodeposited surface is 3.0 μm or more and 5.0 μm or less, and a release agent is applied to the electrodeposited surface.

  In addition, the method for producing a seed plate for copper electrolytic purification provided by the present invention is as follows: the stainless steel mother plate according to the present invention is suspended in an electrolytic cell, and then the electrodeposited copper is electrodeposited by energization. The copper electrodeposited on the electrodeposition surface is peeled off from the stainless steel base plate to form a seed plate.

  According to the present invention, when producing a seed plate for electrolytic purification of copper, the seed plate does not spontaneously peel off from the stainless steel mother plate during electrodeposition, and after the electrodeposition, the seed plate is pulled from the stainless steel mother plate. A stainless steel mother board that can be easily peeled off can be provided. Therefore, by using the stainless steel base plate of the present invention, a seed plate free from wrinkles or tears can be easily manufactured. Moreover, since the stainless steel base plate according to the present invention can achieve a long life, it is extremely advantageous economically.

It is a top view of the stainless steel mother board by the present invention, and has shown nine fields for measuring ten point average roughness (Rz) of an electrodeposition surface.

  The first feature of the stainless steel base plate according to the present invention is that when the substantially quadrangular electrodeposition surface is polished, as shown in FIG. And polished so as to form a plurality of polishing flaws in a direction b (also referred to as a horizontal direction) substantially perpendicular to the vertical direction a (also referred to as a vertical direction), and the surface roughness of the electrodeposited surface 1a is It is adjusted to 3.0 μm or more and 5.0 μm or less. In addition, as a polishing method for the electrodeposited surface, a polishing method using a generally used surface grinder, a traveling wheel polisher, or the like can be used.

  As shown in FIG. 1, the surface roughness of the electrodeposition surface is an average of 10 points in 9 regions obtained by dividing one side of the electrodeposition surface 1a of the stainless base plate 1 and the other side orthogonal to the one side into three equal parts. Roughness (Rz) is measured, and the 10-point average roughness (Rz) obtained for every nine regions is an average value. The ten-point average roughness (Rz) in the nine regions is obtained based on JIS B0601-1994. In addition, although the roughness curve for calculating | requiring ten-point average roughness (Rz) is measured using a stylus-type roughness measuring machine, in this invention, SJ by Mitutoyo Corporation is used as a stylus-type roughness measuring machine. -201 (trade name) was used.

  The second feature of the stainless steel base plate according to the present invention is that the electrodeposited copper seed plate is formed on the electrodeposited surface in which a plurality of polishing flaws are formed in the lateral direction and polished to the specific surface roughness. The release agent is applied for smooth stripping.

  As said release agent, besides a soap solution, varnish, heavy oil, etc., a commercially available release agent can also be used. Examples of commercially available release agents that can be suitably used include ELECUT (trade name) manufactured by Kitahiro Chemical Co., Ltd. These release agents are preferably adjusted to an appropriate concentration by adding water, a solvent, or the like as necessary. In addition, the adhesion amount of a release agent can be calculated | required as a difference of the weight of the mother board after apply | coating and drying a release agent, and the weight of the mother board before application | coating.

  In the stainless steel base plate of the present invention having the first and second features described above, the release agent applied to the electrodeposition surface flows along the lateral polishing scratches formed by polishing, so that the release agent droops. The amount of the release agent retained on the electrodeposition surface by being held in the grooves of the polishing scratches is small. As a result, the seed plate electrodeposited with the stainless steel mother plate of the present invention has improved peelability after electrodeposition, and can effectively suppress the generation of tears and wrinkles.

  Further, the material of the stainless steel base plate in the present invention is not particularly limited as long as it is stainless steel, but it is preferable to use any one of SUS304, SUS304L, and SUS316L from the relationship between corrosion resistance and strength.

  Next, the manufacturing method of the seed plate for copper electrolytic purification using the stainless steel mother board of this invention is demonstrated. As described above, the electrodeposited surface of the mother plate is hung in the electrolytic cell by energizing the stainless steel mother plate of the present invention, in which the electrodeposited surface is polished laterally and a release agent is applied and dried on the electrodeposited surface. Electrodeposit copper on the surface. After the electrodeposition is completed, the copper electrodeposited on the electrodeposition surface is peeled off from the stainless steel base plate to obtain a seed plate for copper electrolytic purification.

  Specifically, when the stainless steel mother board of the present invention is suspended in an electrolytic cell for electrodeposition of copper, as shown in FIG. 1, the upper edge of the stainless steel mother board 1 having a substantially square shape as shown in FIG. The beam 3 is connected to the ear plate 2 provided at three locations of the section, and power is supplied from the beam 3.

  The stainless steel base plate is inserted into the electrolytic cell as a cathode and suspended, and anodes made of crude copper are inserted and arranged at positions facing the front and back electrodeposition surfaces of the base plate. By energizing between the cathode of these stainless steel mother boards and the anode of crude copper, copper is electrodeposited on the electrodeposition surfaces on both the front and back surfaces of the stainless steel mother board. A copper sulfate solution is used as the electrolytic solution, but additives and electrolysis conditions may be selected in accordance with the electrolysis apparatus and process.

  The thickness of the seed plate formed on the electrodeposition surface of the stainless steel mother plate is about 0.6 mm. The formed seed plate is peeled off from the electrodeposition surface of the stainless steel mother board by a peeling device after the electrodeposition is completed. At that time, the seed plate in which the tear or wrinkle has occurred is detected in the inspection process and treated as a defective product.

[Example 1]
Both surfaces of a stainless steel plate made of SUS304 were polished with sandpaper of # 40 to # 240 to produce a stainless steel mother plate having a size of electrodeposition surface of 105 cm × 107 cm. At that time, the polishing direction is set to a direction substantially perpendicular to the vertical direction when suspended in the electrolytic cell (lateral direction) or substantially parallel to the vertical direction (longitudinal direction), and the surface roughness of the electrodeposition surface is changed. Thus, stainless steel mother plates of Samples 1 to 13 were obtained. The surface roughness of the electrodeposition surface is a value obtained by averaging ten-point average roughness (Rz) in nine regions obtained by dividing one side of the electrodeposition surface and the other side orthogonal to the one side into three equal parts.

Each stainless steel base plate subjected to the above-described lateral polishing or vertical polishing was immersed in a stripping solution tank, pulled out, and dried. From the difference between the weight of the stainless steel base plate after the release agent was applied and dried and the weight of the base plate before application, the amount of the release agent adhered was determined. In addition, Kitahiro Chemical Co., Ltd. ELECUT (trade name) was used as the stripping solution, and it was diluted with warm water so that its concentration was 3 kg / m ³ .

  Each of the stainless steel base plates of Samples 1 to 13 was suspended in an electrolytic bath, and electrolyzed under the electrolysis conditions shown in Table 1 below, and copper was electrodeposited on the electrodeposition surface. Thereafter, the stainless steel mother plate was pulled up from the electrolytic cell, and the copper electrodeposited on the electrodeposition surface was peeled off from the stainless steel mother plate to produce a seed plate for copper electrolytic purification.

  After the seed plate was peeled off, the stainless steel mother plate was again coated with a release agent and dried, and then placed in an electrolytic cell, and electrolysis was repeated to produce a seed plate. When a seed plate was manufactured by repeatedly using a stainless steel base plate 160 times, the recovered 160 seed plates were examined for defects and the state of defects that occurred.

  About each stainless steel mother board of samples 1-13, the result of investigating the existence of the above-mentioned defect and the state of the defect together with the polishing direction of the stainless steel mother board, the surface roughness (Rz) of the electrodeposited surface, and the amount of release agent attached are as follows. It is shown in Table 2.

  From the results of Table 2 above, the amount of the release agent attached has a correlation with the polishing direction of the stainless steel base plate and the surface roughness of the electrodeposited surface, and the polishing in the horizontal direction is relatively larger than the polishing in the vertical direction. It can be seen that the release agent remains attached.

  Specifically, spontaneous peeling occurred regardless of the polishing direction when the surface roughness was less than 3 μm, but spontaneous peeling did not occur when the surface roughness was 3 μm or more. Further, in the polishing in the vertical direction, a peeling failure occurred with a surface roughness of 4 μm or more, but in the polishing in the horizontal direction, the peeling failure did not occur up to a surface roughness of 5 μm. From this fact, it was confirmed that even if the surface roughness was almost the same, the laterally polished stainless steel base plate was less effective than the vertical polishing and was more effective.

  Further, among the 160 stainless steel base plates in which defects were not generated in the 160 seed plates produced by repeating the above-described electrolysis, the electrodeposition surfaces of the stainless base plates of Samples 2, 3, 5 and Samples 9, 10, 13 The number of times of annual use until the surface roughness of the steel sheet was increased and discharged beyond the specified range of 5 μm was examined, and the results are shown in Table 3 below.

  As can be seen from the results in Table 3, the lower the initial surface roughness by polishing, the greater the number of repeated uses. However, the stainless steel base plates of Samples 9, 10, and 13 that had been polished in the vertical direction could not be used because the surface roughness increased in about 1 to 4 months. As a result, in the case of vertical polishing base plate with a small amount of stripping solution attached, it is easy to cause corrosion due to electrolytic solution and peeling due to peeling during repeated electrodeposition and peeling of the seed plate. This suggests that the increasing speed of the surface roughness is fast.

  From the above results, the stainless steel base plate polished in the horizontal direction can hold more release agent than the base plate polished in the vertical direction, and can suppress the peeling failure of the electrodeposited seed plate. .

[Example 2]
In the same manner as in Example 1, each stainless steel base plate of Samples 14 to 17 in which the polishing direction was the horizontal direction or the vertical direction and the surface roughness of the electrodeposition surface was changed was produced. Each stainless steel base plate was coated with a release agent in the same manner as in Example 1 and dried, then suspended in an electrolytic cell, and electrolyzed under the electrolysis conditions shown in Table 1 to electrodeposit copper.

  Thereafter, the copper electrodeposited on the electrodeposition surface was peeled off from the base plate to produce a seed plate for copper electrolytic purification. With any stainless steel base plate, a seed plate could be produced without causing defects.

  The stainless steel mother plate from which the seed plate was peeled was again coated with a release agent and dried, and then inserted into the electrolytic cell, and the production of the seed plate by electrolysis was repeated. The surface roughness of the electrodeposited surface was increased, and the use range exceeded 5 μm, which was the specified range, and the number of repeated use until it was dispensed was examined. The results are shown in Table 4 below.

  As can be seen from Table 4 above, the stainless steel base plates of Samples 14 to 15 that are polished in the lateral direction and the surface roughness of the electrodeposited surface is within the scope of the present invention, even if the release agent concentration is dilute, It has been found that a seed plate is obtained that is excellent in holding a seed plate during electrolysis, does not spontaneously peel, and does not break or wrinkle due to good peelability.

1 Base plate 1a Electrodeposition surface 2 Ear plate 3 Beam

Claims (2)

  The electrodeposition surface used for the production of the copper electrorefining seed plate is a substantially rectangular stainless steel mother plate, and a plurality of the electrodeposition surfaces in a direction substantially perpendicular to the vertical direction when suspended on the electrolytic cell on the surface of the electrodeposition surface The surface roughness of the electrodeposited surface obtained by averaging the ten-point average roughness (Rz) in nine regions each having a polishing flaw and dividing one side of the electrodeposited surface and the other side orthogonal to the one side into three equal parts. A stainless steel mother board having a thickness of 0.0 μm or more and 5.0 μm or less, and a release agent applied to the electrodeposition surface.   The stainless steel base plate according to claim 1 is suspended in an electrolytic cell, and copper is electrodeposited on the electrodeposition surface by energizing, and then the copper electrodeposited on the electrodeposition surface is peeled off from the stainless steel base plate. A method for producing a seed plate for copper electrolytic purification, characterized by using a seed plate.

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