JPS6026689A - Method and device for producing metallic foil by electrodeposition - Google Patents

Abstract

PURPOSE:To produce efficiently metallic foil with a high current density without inducing corrosion of equipment by performing electrodeposition by using an electrolytic cell in which a rotary drum cathode and an insoluble anode are disposed separately in a way as to face each other via an anion exchange membrane. CONSTITUTION:A drum-shaped electrolytic cell 2 is separated and segmented to an anode chamber 4 and a cathode chamber 5 by an anion exchange membrane 3 with a device 1 for producing metallic foil by electrodeposition. A rotary drum 10 constituting a cathode is provided in the chamber 5 and an electrolyte 11 which is a catholyte is filled therein and is passed between an inlet and outlet 12, 13. An insoluble anode 9 is concentrically provided outward along the drum 10 in the chamber 4 and an anolyte 7 is filled therein and is passed through an inlet 6 to an outlet 8. A roll seal 14 is further provided in a cathode chamber 11 to seal the chamber. While the drum 10 is rotated, electrolytic current is impressed on both electrodes 9 and 10 and the metallic foil electrodeposited on the drum 10 is stripped by a roll 15 and is taken up on a take-up roll 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing metal foil by electrodeposition, and particularly to a method and apparatus for producing Fe-based metal foil by electrodeposition using an insoluble anode.

Metal foils, particularly Fe-based metal foils, are manufactured by electrolytic methods or rolling methods, and most of them are manufactured by electrolytic methods because they are easy to manufacture. However, the above electrolytic method has conventionally been carried out using a soluble anode, and therefore has the following drawbacks.

(1) Since the anode is a soluble anode, the anode wears out, and as a result, the distance between the anode and the drum, which is the cathode, increases.

(2) As a result, the interelectrode voltage increases, resulting in an increase in power cost, and there is a limit to the ability to increase current density.

(3) Therefore, the high current density could not be removed, and the manufacturing speed was slow.

(4) It was necessary to replace the anode that was consumed during electrolysis.

(5) Furthermore, in order to uniformly dissolve the Fe anode, which is a soluble anode, it is necessary to use a highly corrosive chloride bath, resulting in equipment corrosion problems.

On the other hand, when an insoluble anode is used, instead of dissolving Fe from the anode, a reaction occurs in which Fe2+ ions in the electrolytic bath are oxidized to Fe3+ ions, and an increase in Fe3+ ions in the electrolytic bath is unavoidable. The current efficiency of Fe deposition is reduced, and gas generation occurs simultaneously with the production of Fe3+ ions, resulting in an increase in voltage. Therefore, the efficiency of the entire electrolytic operation is significantly reduced.

An object of the present invention is to provide a method and apparatus for manufacturing metal foil by an electrolytic method using a drum-type electrolytic cell, which eliminates the drawbacks of the prior art as described above. be.

Therefore, the present inventors focused on the advantages of insoluble anodes,
As we continued our research and development efforts to utilize this technology, we discovered that in order to suppress the oxidative production of Fe3+ ions in the electrolytic bath, which is a drawback when using an insoluble anode, an anion ion exchange membrane was The inventors discovered that it is necessary to provide an insoluble anode in the anode chamber separated and partitioned, and that this can effectively prevent the production of Fe 34 ions, and have completed the present invention.

That is, the gist of the present invention is as follows: (1) In a method for producing metal foil by electrodeposition using a drum-type electrolytic cell, an anion exchange membrane separates and partitions a metal foil from a rotating drum constituting a cathode. An insoluble anode is provided in the anode chamber, and the insoluble anode is placed opposite to the outer peripheral surface of the rotating drum via the anion ion exchange membrane,
(2) a method for producing metal foil by electrodeposition, characterized in that metal is electrodeposited on the rotating drum in a state where the anolyte and the catholyte containing metal ions are separated by the anion ion exchange membrane; and (2) a cathode. a rotating drum constituting the rotating drum, one or more anode chambers spaced apart from the rotating drum, a cathode chamber formed between the anode chamber and the outer surface of the rotating drum, and an anolyte supply to the anode chamber. The anode chamber is composed of an insoluble anode and an anion ion exchange membrane spaced apart from the insoluble anode, and the anion ion exchange membrane is This is an apparatus for producing metal foil by electrodeposition, which is in contact with the cathode chamber through the membrane and is separated and partitioned from the cathode chamber by the anion ion exchange membrane.

The anode chamber may be composed of 11 [1i1 anode chambers] in a semi-cylindrical shape surrounding the rotating drum, or may be constructed entirely or partially by arranging two or more anode chambers in the same manner. Alternatively, the anode chamber may surround the rotating drum in a semi-cylindrical manner. Preferably, the insoluble anode is also arranged concentrically with respect to the rotating drum.

When a plurality of anode chambers are provided, each may be provided with an anolyte supply/discharge mechanism, for example, a supply port and a discharge port. On the other hand, a catholyte supply mechanism, that is, a catholyte jetting nozzle, is installed at an appropriate position in the cathode chamber, preferably between one anode chamber and an adjacent anode chamber, so that one or both ends of the cathode chamber are open ends. The catholyte may overflow and flow out from there.

Furthermore, when a plurality of anode chambers are used, the anion ion exchange membrane may be provided in a planar manner in each anode chamber. Even in that case, each insoluble anode is preferably arranged concentrically with respect to the rear surface of the rotating drum.

Adjust the flow relationship of the can liquid so that the flow direction of the catholyte is countercurrent to the moving direction of the metal foil to be electrodeposited, and the flow direction of the anolyte is countercurrent to the flow direction of the catholyte. It is preferable to do so.

Therefore, according to the present invention, since the insoluble anode is used, the distance between the electrodes and the cathode can always be kept constant and accurate, and the distance between the electrodes can also be shortened, thereby reducing power costs. It is also possible to improve the efficiency of current utilization by reducing the current density and increasing the current density. Moreover, since the cathode and anode are completely separated from each other due to the movement of metal ions, if the elution of metal ions is limited to the cathode drum side, that is, the cathode chamber, it will have a negative effect on Fe precipitation on the cathode drum. The generation of Fea+ ions can be completely suppressed, and this also makes it possible to improve the efficiency of plating operations.

As already mentioned, the present invention uses an insoluble anode as an anode in the production of metal foil using a drum-type electrolytic cell, particularly in the production of FeM, and separates and partitions this from the cathode drum using an anion ion exchange membrane. It is. Anion exchange membranes allow anions to pass through, but do not allow cations such as Fe2+ ions to pass through. Therefore, by separating and partitioning the anode with an anion exchange membrane, F
E2+ ions can be prevented from coming into contact with the anode, and therefore, oxidation of Fe2+ ions, that is, oxidation generation of Fe3+ ions, is suppressed.

Anion exchange membranes are already known, and there are no particular limitations as long as they can prevent the movement of metal ions as described above.
Commercially available products can be used as appropriate. An example is Neocepta (trade name, Tokuyama Soda).

Examples of anions include halogen ions, sulfate ions, sulfamine ions, and sulfone ions, and are not particularly limited, but sulfate ions are preferably used.

In the case of sulfate ions, when electrodeposition is carried out using an aqueous ferrous sulfate solution in the electrolytic bath, S○42- ions, which are anions, are collected in the anode chamber. In this case, sulfuric acid will eventually be produced in the anode chamber, and this sulfuric acid will be taken out of the system.

In addition, when using sulfate ions, either the consumed Fe2+ ions are replenished into the system in the form of ferrous sulfate at the cathode, or the Fe2+ ions are replenished with sulfuric acid taken out of the system as described above. Either method may be used, such as melting the liquid and circulating it in the electrolytic cell. However, the former method has the advantage that ferrous sulfate, which is industrially inexpensive, can be used.

The insoluble anode material should be selected depending on the type of electrolytic bath used, but generally includes Pb, alloys thereof, Pt group metals, carbon, ferrite, and the like.

Note that the production of metal foil according to the present invention is not necessarily limited to Fe foils, and can in principle be applied to the production of multivalent ionic metal foils whose ionic valence changes due to an oxidation reaction at the anode. Examples include Fe alloy foil, CO or 00 alloy foil, Sn or Sn alloy foil, and the like.

The invention will now be further described in connection with the accompanying drawings. In addition, although Fe foil is taken as an example of the metal foil in the following description, it is clear from the above description that the present invention is not limited to this. Note that in each figure, the same members are indicated by the same symbols.

FIG. 1 is a schematic explanatory diagram showing a partial cross section of an apparatus 1 for producing metal foil by electrodeposition according to the present invention. The drum type electrolytic cell 2 is separated into an anode chamber 4 and a cathode chamber 5 by an anion ion exchange membrane 3. The anode chamber 4 is filled with an anolyte 7 from an anolyte reservoir 6 by a pump (not shown). The anion-concentrated anolyte is taken out from the anolyte outlet 8. In the illustrated example, a single anode chamber is provided. In the anode chamber 4, an insoluble anode 9 is installed concentrically outward along the cathode drum 10 and separated and partitioned from the cathode drum. On the other hand, an electrolyte 11, which is a catholyte for electrodepositing Fe, is supplied from an electrolyte outlet 12 and discharged from an electrolyte outlet 13. In the illustrated example, the cathode chamber 5 is sealed by a seal roll 14 . The electrolytic solution 11 is always fully filled in the cathode chamber 5, and metal is electrodeposited as the cathode drum 10 rotates. The Fe deposited on the cathode drum 1° in this manner is peeled off from the cathode drum by an appropriate means (not shown) such as a scraper, passes through a guide roll 15, and is wound as an electrolytic Fe foil on a winding roll 16. taken.

FIG. 2 schematically shows an example in which a plurality of anode chambers 4 are provided around the outside of the cathode drum 10. Each anode chamber (shown in side view in the figure) 4 has an anolyte supply port 17. On the other hand, the catholyte 11 is blown into the cathode chamber 5 by a jet nozzle 19 installed between the anode chambers, and a part of the catholyte is blown from the catholyte outlet 13. , and the others overflow from both end edges and are discharged, respectively. The anion ion exchange membrane 3 is arranged concentrically with the outer surface of the cathode drum 10. In order to keep the inter-electrode distance constant, each insoluble anode (not shown) is also arranged concentrically.

In addition, in the case of the illustrated example, faster processing can be performed compared to the apparatus shown in FIG.

FIG. 3 schematically shows a case in which a plurality of anode chambers 4 are similarly provided, and the anode chamber is shown in a side view.

In the illustrated example, a plurality of catholyte injection nozzles 20 are provided in place of the catholyte injection nozzle, so that the catholyte ejected in the same direction overflows from one edge and is discharged. In this case, the anion ion exchange membrane 3 is arranged in a planar manner in each anode chamber, and therefore the installation of the ion exchange membrane is much easier than in the case of FIGS. 1 and 2.

FIG. 4 shows a flowchart of the electrolyte when the apparatus shown in FIG. 1 is used and ferrous sulfate is used as the Fe foil raw material.

In this case, the electrolytic bath consists of an aqueous ferrous sulfate solution.

Since Fe2+ ions in the electrolytic bath are reduced by electrodeposition,
Line 2 is pumped from the electrolyte tank 21 using appropriate pumps.
2, Fe2+ ions are supplied to the cathode chamber 5 in the form of ferrous sulfate. The electrolytic solution discharged from the electrolytic cell is returned to the electrolytic solution tank 21 via a line 23. Replenishment ferrous sulfate is supplied via line 24. On the other hand, 3 from ferrous sulfate
042'' is transferred to the anode chamber 4 through the anion ion exchange membrane 3 as a diaphragm.The anode chamber 4 has a sulfuric acid water tank 25.
Therefore, sulfuric acid is circulated through line 26 using appropriate pumps. Therefore, as the electrolysis continues, the amount of sulfuric acid in the anode chamber increases, and the increased amount is taken out of the system through the sulfuric acid water line 28, which is taken out through the line 27.

In the case of the apparatus shown in Fig. 4, the diameter of the cathode drum is 500 mm, the anode is a PB anode, and the distance between the electrodes is 5.
~10mm, electrolyte supply amount 2000 N/m
Fe foil production was carried out at a current density of 40 to 100 A/dm2, with an anolyte supply of 1 t5001/min and a current density of 40 to 100 A/dm2.

The current efficiency at that time was 60 to 80%. Neosepta (product name, Tokuyama Soda) is an anion ion exchange membrane.
I used

In this example, the Fe3+ production rate in the cathode chamber was measured using a current density of 100 A/dm2 and a catholyte of Fe2+IM/β as the electrolyte. For comparison, similar experiments were conducted using a conventional apparatus using an insoluble anode but no anion exchange membrane.

The results are summarized in a graph in FIG. According to the present invention, it can be seen that the production rate of Fe3+ in the electrolytic bath is almost substantially zero. In the figure, . indicates an example of the present invention, and .largecircle. indicates a conventional example.

Similarly, NiSO42M/E, FeSO
40,5M/ 12, pH 2, and current density 60^/
Fe-alloy plating was performed under electrolytic conditions of dm2, and the inter-electrode voltage was measured while varying the inter-electrode distance. For comparison, a similar experiment was conducted using a conventional apparatus using an insoluble anode but no anion exchange membrane. The results are summarized in a graph in FIG. In the figure, . indicates an example of the present invention, and .largecircle. indicates a conventional example. As is clear from the results shown in FIG. 7, according to the present invention, the voltage between the electrodes does not increase even if the distance between the electrodes is as close as 5 mm, whereas the conventional method using an insoluble anode By reducing the distance between the electrodes, gas bubbling at the anode becomes noticeable, and the voltage between the electrodes increases significantly.

As described above, it can be seen that according to the present invention, the distance between the electrodes can be made extremely close, and energy saving can be realized accordingly.

Next, FIG. 5 shows that F
2 is a flowchart showing a process of melting Fe and utilizing Fe2+ ions of Fe thus melted in place of Fe2+ ions as ferrous sulfate. A portion of the increased sulfuric acid is extracted from the circulation system of the anode chamber 4 through the line 31 and introduced into the iron dissolving tank 32 (here, Fe and sulfuric acid are reacted to melt the Fe and turn it into a solution of ferrous sulfate. ,
Next, the line 33 is led to the electrolytic bath tank 24, and the line 22 is led to the cathode section 5.

In the case of the apparatus shown in FIG. 5, the drum-type electrolytic cell shown in FIG.
/dm2, and when manufacturing Fe foil with a distance between poles close to 2 to 5 mm, the current efficiency at that time was 70
It was ~85%.

As described above, according to the present invention, in any embodiment, the distance between the electrodes and the electrolyte composition can be maintained constant and close for a long period of time, and Fe foil with stable quality can be manufactured. I understand.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing a partial cross section of the Fe foil manufacturing apparatus according to the present invention; FIGS. 2 and 3 are schematic explanatory diagrams showing modified examples of the present invention; FIGS. 4 and 5 The figure is a flowchart showing the supply system of the electrolyte and the anolyte; and FIGS. 6 and 7 are graphs obtained by plotting experimental data of Examples of the present invention. 2 Ni drum type electrolytic cell 3: Anion ion exchange membrane 4; Anode chamber 5: Cathode chamber 9: Insoluble anode 10: Cathode drum Applicant Sumitomo Metal Industries Co., Ltd. agent Patent attorney Akira Hirose - Pole, 7 illustrations 3 Figure 0 Fox figure 4 also figure 5

Claims (5)

[Claims] (1) In a method for manufacturing metal foil by electrodeposition using a drum-type electrolytic cell, an insoluble anode is provided in an anode chamber separated and partitioned from a rotating drum constituting the cathode by an anion ion exchange membrane, and The insoluble anode is disposed opposite to the outer peripheral surface of the rotating drum through an anion ion exchange membrane, and the metal is placed on the rotating drum with the anolyte and the metal ion-containing catholyte separated by the anion ion exchange membrane. A method for producing metal foil by electrodeposition, characterized by electrodepositing. (2) A rotating lower ram constituting a cathode, one or more anode chambers spaced apart from each other on the outside of the rotating drum, a cathode chamber formed between the anode chamber and the outer surface of the rotating drum, and the anode chamber. and a catholyte supply and discharge mechanism to the catholyte chamber, the anode chamber comprising an insoluble anode and an anion ion exchange membrane spaced and opposed to the insoluble anode, An apparatus for producing metal foil by electrodeposition, which is in contact with the cathode chamber via the anion ion exchange membrane and is separated and partitioned from the cathode chamber by the anion ion exchange membrane. (3) The anode chamber is comprised of a 1t [lil anode chamber having a semi-cylindrical shape surrounding the rotating drum, and the insoluble anode and anion ion exchange membrane are arranged concentrically with respect to the outer surface of the rotating drum. , Claim No. 2
). (4) The anode chamber is composed of two or more anode chambers that surround the rotating drum and form at least a portion of a semi-cylindrical portion as a whole, and the insoluble anode and anion ion exchange membrane are attached to the outer surface of the rotating drum. , arranged concentrically, the device according to claim (2). (5) The anion ion exchange membrane is arranged on each plane in each anode chamber,
The device described in section 4).