JP2002004095A - Insoluble anode and its power supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide insoluble anodes which are capable of manufacturing uniform metallic films at the same current density over the entire part of the electrode surfaces of the insoluble anodes and are uniform in the consumption of the electrode active surfaces without unevenness and a power feeding method for the same. SOLUTION: Constant currents are passed respectively independently from a plurality of power sources 4 to respective terminals 3 for anode power feeding, a plurality of which are joined to the cathode rear surface side of the insoluble anodes arranged at specified intervals along the curved surface of a cylindrical cathode in such a manner that the entire part of the electrode surfaces attains the same current density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insoluble anode used for continuous plating by high current electrolysis, production of metal foil, and the like, and a power supply method thereof.

[0002]

2. Description of the Related Art In the field of continuous plating by electrolysis and in the field of metal foil production by electrolysis, reductions in the distance between electrodes, higher speed, and higher current density are progressing due to technological advances. On the other hand, in the production of metal foil, stricter uniformity and thinner metal foil are required.

In general, in a continuous metal foil producing apparatus by electrolysis, an electrolytic solution containing metal ions is caused to flow between a cylindrical cathode and an anode arranged at regular intervals along a curved surface of the cylindrical cathode to perform electrolysis. Although a method of depositing a metal foil on the cathode surface has been adopted, since the metal ion concentration is lower at the electrolyte outlet than at the electrolyte inlet, a current density distribution occurs at the same anode, so that a uniform There is a problem that the metal foil cannot be formed, and the consumption of the electrode active surface of the anode becomes non-uniform.
In addition, since the current density is concentrated on the peripheral edge of the anode due to the edge effect, the thickness of the metal foil near the peripheral edge of the anode increases, and the consumption of the electrode active surface of the peripheral edge of the anode increases. Have. .

In order to solve the above problems, Japanese Patent Laid-Open Publication No.
Japanese Patent No. 225991 discloses that a linear insoluble metal electrode is arranged on an electrode substrate, the interval between the linear insoluble metal electrodes is increased in a portion where the current density is concentrated, and the linear insoluble metal electrode is arranged in a portion where the current density is small. An electrode for electrolysis in which the distance between metal electrodes is made small is disclosed. Japanese Patent Application Laid-Open No. 7-41980 discloses an electrode for electrolysis in which an insoluble metal electrode having an opening on the surface of an electrode substrate and an insoluble metal electrode whose opening ratio is changed according to current density are arranged. ing.

[0005] However, these methods can cope with uniformity of the current density to some extent, but are not suitable for a new apparatus in which the current density distribution cannot be predicted, a change in the operation condition, or an operation condition due to the formation condition of the metal foil. In the case where feedback is given to a group, it is insufficient and there are still points to be resolved.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal foil having a uniform thickness without unevenness by freely controlling each part of an electrode surface to an optimum current density.
Another object of the present invention is to provide an insoluble anode in which an electrode active surface is not consumed unevenly and a power supply method therefor.

[0007]

As a result of intensive studies, the present inventors have joined a plurality of anode power supply terminals to the cathode back side of the insoluble anode, and provided a plurality of anode power supply terminals to each of the anode power supply terminals. It has been found that the above-mentioned problems can be solved by supplying a constant current to each of the power supplies independently, and the present invention has been completed.

That is, the present invention is characterized in that, in an insoluble anode arranged at regular intervals along the curved surface of a cylindrical cathode, a plurality of anode power supply terminals are joined to the cathode back side of the insoluble anode. The present invention also provides a plurality of anode power supply terminals joined to a plurality of insoluble anodes arranged on the cathode back side arranged at regular intervals along the curved surface of the cylindrical cathode. From the power supply
This is a power supply method characterized by supplying a constant current independently.

Hereinafter, the present invention will be described in detail with reference to FIG.

FIG. 1 is an example of a schematic view showing the outline of the insoluble anode of the present invention. In addition, this invention is not limited at all by FIG.

FIG. 1 shows a structure in which a plurality of anode power supply terminals 3 are joined to the back surface side of a cathode of an insoluble anode composed of an electrode base 2 having an electrode active surface 1 processed in accordance with the curved surface shape of a cylindrical cathode. 5 shows that the plurality of power supplies 4 and the anode power supply terminals 3 are independently connected.

The insoluble anode of the present invention is produced by the following method.

First, an anode power supply terminal 3 also made of a valve metal is placed on the back side of the cathode of an electrode base 2 made of a valve metal processed according to the curved surface shape of a cylindrical cathode.
Are joined together.

The valve metals used as the electrode substrate 2 and the anode power supply terminal 3 include titanium, niobium, and the like.
Tantalum, zirconium and the like can be mentioned, and titanium is preferable because it is inexpensive and easy to process.

The anode power supply terminal 3 is joined to the electrode base 2 by welding or screwing.

In the case of screwing, a female screw is cut into the electrode base 2 in advance, and a male screw is cut into a portion of the anode power supply terminal 3 to be attached to the electrode base 2, and the anode power supply terminal 3 is screwed into the electrode base 2. Join. Joining by screwing is troublesome in drilling a hole in the electrode base 2, and the threaded portion may be loosened, increasing the contact resistance. Therefore, joining by welding is preferred.

The anode power supply terminal 3 has an electrode area of 0.1 mm.
It is joined to the electrode base 2 at a rate of one piece per 5 to 5.0 dm ² . When the electrode area is less than 0.5 dm ² , the number of anode power supply terminals 3 is extremely large, which is not economical. If it exceeds 5.0 dm ² , the control of the current density distribution becomes insufficient, which is inconvenient.

After the plurality of anode power supply terminals 3 are joined to the electrode substrate 2 as described above, the electrode active layer 1 of a platinum group metal or its oxide is placed on the cathode side of the electrode substrate 2. Cover.

As the platinum group metal or its oxide as the electrode active layer 1 to be coated on the electrode substrate 2, there may be mentioned known ones such as platinum, platinum oxide, tantalum, tantalum oxide and iridium oxide. The main component of the electrode active layer 1 is preferably iridium oxide, and may contain platinum, tantalum, palladium, or ruthenium.

The electrode active layer 1 is coated on the electrode substrate 2 by a known method such as a baking method, and the insoluble anode of the present invention is produced.

The insoluble anode produced as described above is
After being installed in an electrolytic facility such as a continuous copper foil manufacturing apparatus, the anode power supply terminal 3 and the plurality of power supplies 4
The anode power supply terminals 3 are independently connected to each other, and are operated by supplying a constant current to the anode power supply terminals 3 independently.

A constant current is supplied to the anode power supply terminal 3 independently from the plurality of power supplies 4 to control the constant current, so that the current density over the entire electrode surface of the insoluble anode is the same. be able to.

When the change in current density is small,
The anode power supply terminal 3 may be divided into several blocks, each block may be connected to a power source independently, and a constant current may be supplied independently for each block. .

According to the above-described power supply method, the entire electrode surface of the insoluble anode has the same current density, a uniform metal foil can be manufactured, and the consumption of the electrode active surface of the insoluble anode becomes uniform. In addition, efficient operation can be performed, operation can be performed at low running cost, and economic efficiency is excellent.

[0025]

The continuous metal foil manufacturing apparatus is capable of flowing an electrolytic solution containing metal ions between a cylindrical cathode and an anode arranged at a constant interval along the curved surface of the metal foil, and electrolyzing the metal foil on the cathode surface. At the electrolyte outlet, the metal ion concentration is lower than at the electrolyte inlet, so the current density near the electrolyte inlet is higher, the metal foil is thicker near the electrolyte inlet, and near the electrolyte outlet. The thin metal foil makes it difficult to obtain a uniform metal foil, and in areas where the current density is high, the electrode active surface is quickly consumed, and the electrode active surface is not uniformly consumed. In this case, the current density becomes higher than that of the central part of the electrode due to the edge effect, so that the metal foil becomes non-uniform, and at the same time, the consumption of the electrode active surface becomes non-uniform.

A power supply method is used in which a plurality of power supplies 4 independently supply a constant current to each of the insoluble anodes having a plurality of anode power supply terminals 3 joined to the cathode back side of the insoluble anode. Therefore, when electrolysis is performed, the optimal constant current control is performed independently for each part of the electrode surface, so that the electrolyte inlet and the electrode periphery, where the current density tends to be high, and the current density The same constant current can be applied to the electrolyte outlet and the center of the electrode, which tend to be low, and the current density on the entire electrode surface can be the same, so that a uniform metal foil can be manufactured and the electrode active surface is consumed. Can be made uniform.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail based on examples. Note that the present invention is not limited to these Examples.

Example 1 An electrode substrate 2 was made of a titanium plate (20 m thick) as a valve metal.
m) is cut to a width of 1.5 m and a quarter cylindrical shape (2 m in diameter)
After processing into φ), an anode power supply terminal 3 made of titanium was welded to the convex surface (cathode back surface) side at a rate of one per 3 dm ^{2 of} electrode area.

After degreasing the above electrode substrate, it was immersed in 10% oxalic acid at a temperature of 80 ° C. for 5 hours to roughen the surface. Then, a coating solution comprising iridium chloride and tantalum chloride in a ratio of iridium: tantalum of 6: 4 (molar ratio) was applied to the concave side (cathode side) of the electrode substrate, and baked at a temperature of 500 ° C. for 30 minutes. This operation was repeated 20 times to produce an insoluble anode.

The insoluble anode prepared above was placed at a distance of 10 mm between the electrodes so as to surround the lower half of the cylindrical cathode of the electrolytic device for producing a continuous metal foil. Each independently from the wiring 5
And the constant current flowing through each anode power supply terminal 3 can be independently controlled.

An electrolytic solution consisting of 200 g / L of copper sulfate and 100 g / L of sulfuric acid was circulated from the lower part of the electrolytic cell to the upper part at a rate of 30 cm / min by a pump in the above-mentioned electrolytic apparatus. Constant current electrolysis at a density of 50 A / dm ² was continuously performed for 1000 hours to produce a copper foil having a thickness of 20 μm.

The thickness error of the manufactured copper foil is ± 1.0.
%Met. Also, the thickness of the electrode active layer of the insoluble anode,
It was observed that it was uniformly reduced without unevenness.

Comparative Example 1 A 20-μm thick copper was prepared in the same manner as in Example 1 except that one anode power supply terminal 3 was welded only to the center portion of the electrode substrate 2 on the cathode back side. A foil was produced.

The thickness difference between the copper foil near the electrolyte inlet and the copper foil near the electrolyte outlet is about 20%, and the difference between the thickness of the copper foil at the center of the electrode and the thickness of the copper foil at the periphery is about 20%. Was about 15%.
Further, it was observed that the thickness of the electrode active layer of the insoluble anode was reduced by about 10% or more at the electrolyte inlet portion than at the electrolyte outlet portion.

[0035]

A power supply method in which a plurality of power supplies 4 independently supply a constant current to each of the insoluble anodes having a plurality of anode power supply terminals 3 joined to the cathode back side of the insoluble anode. When the electrolysis is performed using an electrode, the optimal constant current control is performed independently for each part of the electrode surface, so that the electrolyte inlet and the electrode peripheral portion where the current density tends to be high, and the current density The same constant current can flow to the electrolyte outlet and the center of the electrode, which tend to be low, and the current density on the entire electrode surface can be the same. The wear can be made uniform.

Also, since the consumption of the electrode active layer can be made uniform, the electrode replacement time can be extended, which is very economical.

[Brief description of the drawings]

FIG. 1 is an example of a schematic view schematically showing an insoluble anode of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrode active layer 2 electrode substrate 3 anode power supply terminal 4 power supply 5 wiring

Claims (5)

[Claims] 1. An insoluble anode, comprising a plurality of insoluble anodes arranged at regular intervals along a curved surface of a cylindrical cathode, wherein a plurality of anode power supply terminals are joined to the cathode back side of the insoluble anode. 2. The insoluble anode according to claim 1, wherein the anode power supply terminal is joined by welding or screwing. 3. An anode power supply terminal having an electrode area of 0.
2. The insoluble anode according to claim 1, wherein one is bonded at a rate of 5 to 5.0 dm < ² >. 4. A constant current is supplied by a plurality of power supplies to each of a plurality of anode power supply terminals joined to the cathode back side of insoluble anodes arranged at regular intervals along the curved surface of the cylindrical cathode. A power supply method characterized in that power is supplied independently of each other. 5. An anode power supply terminal joined to a plurality of insoluble anodes, which are arranged at regular intervals along the curved surface of a cylindrical cathode, and are joined to at least two blocks or more, are divided into at least two blocks or more. Depending on the power supply,
A power supply method characterized in that power is supplied independently of each other.