JP2000026987A - Bipolar electrolytic cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bipolar electrolytic cell consisting of unit electrolytic cells which ensure the easy and fail-proof conduction of welding work, are free from the occurrence of crack and distortion and are excellent in cost effectiveness. SOLUTION: Bent parts 3a and 13a are formed at least one end of the anode ribs and cathode ribs of the electrolytic cell having the anode ribs 3 and anode pans 2 forming anode chambers, the cathode ribs 13 and anode pans 12 forming cathode chambers and clad plates 9 disposed between the anode pans and the cathode pans. The anode ribs and the anode pans, the anode pans and the clad plates, the clad plates and the cathode pans and the cathode pans and the cathode ribs are respectively joined by spot welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bipolar electrolytic cell for producing chlorine and an alkali metal hydroxide by electrolyzing an aqueous alkali metal chloride solution.

[0002]

2. Description of the Related Art Various types of electrolytic cells have been developed and proposed as ion exchange membrane type electrolytic cells for electrolyzing an aqueous solution of an alkali metal chloride, for example, a saline solution.
FIG. 3 is a schematic cross-sectional view schematically showing almost the upper half of a unit electrolytic cell constituting a typical bipolar electrolytic cell conventionally employed, and FIG. 4 is an anode in a conventional unit electrolytic cell. FIG. 3 is a schematic plan view showing the vicinity of a cathode. 3 and 4
, (1) is an anode, (11) is a cathode, (2) is an anode pan, (12) is a cathode pan, (3) is an anode rib, and (13) is a cathode rib. Also, anode ribs (3)
The cathode ribs (13) are provided with a plurality of openings (7) serving as passages for the electrolytic solution and the electrolytic product.

The anode (1) and the anode pan (2) are welded to each other through an anode rib (3) to form an anode chamber (4). Similarly, the cathode (11) and the cathode pan (12) are The cathode chambers (1) are welded through the cathode ribs (13), respectively.
4) is formed. The upper and lower ends of the anode (1) and the cathode (11) are fixed by gaskets (5), respectively, and the upper and lower ends of the anode pan (2) and the cathode pan (12) are upper (lower) frames (6).
Respectively. An anode pan (2) and an anode rib (3) forming an anode chamber (4) on the anode side where chlorine gas is generated are made of, for example, a titanium material having excellent corrosion resistance, and a cathode that generates sodium hydroxide and hydrogen. Pan (12) and cathode rib (1) forming a cathode chamber (14) on the side
3) is made of, for example, a nickel material having excellent alkali resistance.

[0004] (9) is a clad plate obtained by processing nickel and titanium or stainless steel and titanium by an explosion compression method, and the clad plate (9) is located at a predetermined position between the anode pan (2) and the cathode pan (12). The titanium side of the cladding plate (9) is welded to the anode pan (2), and the nickel side or stainless side is welded to the cathode pan (12). (8) The anode pan (2) and the cathode pan (1)
This is an expanded metal provided above and below the cladding plate (9) between the metal plates 2). Reference numeral (10) denotes an ion exchange membrane sandwiched between a cathode (11) and an anode (1) as a diaphragm, and upper and lower ends of the ion exchange membrane (10) are fixed by gaskets (5).

An electrolytic cell having a large number of unit electrolytic cells sandwiching the above-described ion exchange membrane (10) arranged in parallel, and having only an anode chamber provided with a terminal for flowing a current at one end;
An electrolytic cell having only a cathode chamber provided with a terminal for allowing a current to flow at the other end is arranged, and the frame is tightened with a hydraulic press or the like to prevent leakage of the liquid, thereby obtaining a bipolar electrolytic cell.
The anode rib (3) and the cathode rib (13) of the unit electrolytic cell constituting such a bipolar electrolytic cell are plate-shaped, and the anode rib (3) is an anode pan (2) and a cathode rib (13). Are arranged orthogonally to the cathode pan (12), respectively, and weld the anode rib (3) and the anode pan (2), weld the cathode rib (13) to the cathode pan (12), or The welding of the pan (2) and the clad plate (9) and the welding of the cathode pan (12) and the clad plate (9) are all performed by Tig.
It was generally done manually by welding (FIG. 4).

[0006]

However, in the conventional manual Tig welding, the welding frequency is high, so that the assembling time of the electrolytic cell is lengthened, the productivity is low, the processing accuracy is reduced, and the operator is not allowed to work. It is difficult to control welding conditions due to the skill level of welding, and uneven welding may occur, resulting in insufficient strength and variation in electrical resistance.Also, cracks may easily occur due to the amount of heat generated during welding, which may cause electrolyte leakage. There is a fear that the ion exchange membrane may be damaged or the chamber frame may be distorted. In addition, when joining the plate-shaped rib and the pan, there still remains a problem that a troublesome welding operation is involved. Further, using a clad plate of nickel and titanium increases the cost, and using a clad plate of stainless steel and titanium has a problem that the electric resistance value is high.

Accordingly, the present invention has been made to solve the above-mentioned various problems, and is an economical unit which can perform welding work easily and reliably and does not cause cracks or distortion. An object of the present invention is to obtain a bipolar electrolytic cell comprising an electrolytic cell.

[0008]

SUMMARY OF THE INVENTION The present invention provides the following bipolar electrolytic cell in order to achieve the above objects. That is, an anode rib and an anode pan forming an anode chamber, a cathode rib and a cathode pan forming a cathode chamber, and an electrolytic cell having a clad plate disposed between the anode pan and the cathode pan, A bipolar electrolytic cell characterized in that an anode pan, an anode pan and a clad plate, a clad plate and a cathode pan, and a cathode pan and a cathode rib are respectively joined by spot welding. The anode rib has a bent portion in contact with at least one of the anode and the anode pan, and the cathode rib is formed into a shape having a bent portion in contact with at least one of the cathode and the cathode pan. The clad plate further comprises titanium having a thickness of 0.7 mm or less;
It is characterized by being constituted by a rolled steel material for general structure of 0 mm or more.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 is a schematic plan view showing the periphery of an anode and a cathode in a unit electrolytic cell constituting a bipolar electrolytic cell according to the present invention, and FIG. 2 is a schematic plan view showing another embodiment of an anode rib and a cathode rib. is there. 1 and 2, the same or equivalent members as those in FIGS. 3 and 4 are denoted by the same reference numerals.

As described above, the anode chamber (4) is formed by the anode (1), the anode pan (2) and the anode rib (3),
The cathode chamber (14) is formed of a cathode (11), a cathode pan (12) and a cathode rib (13), and the members are joined so as to be conductive. The clad plate (9)
The anode pan (2) is made by processing titanium and inexpensive, low-resistance electrical steel (Structural Steel) for general structural use (hereinafter referred to as SS material) by an explosion compression method.
Is the titanium side of the clad plate (9) and the cathode pan (1
2) is joined to the SS material side of the clad plate (9), respectively.

At this time, the anode rib (3) and the anode pan (2), the anode pan (2) and the clad plate (9), the clad plate (9) and the cathode pan (12), and the cathode pan ( 12) and the cathode rib (13) are respectively joined by spot welding. The anode pan (2) and the cathode pan (1
The thickness of 2) is preferably about 1.0 mm, and the thickness of the anode rib (3) and the cathode rib (13) is preferably about 1.5 mm. The thickness of titanium of the clad plate (9) is preferably 0.7 mm or less from the viewpoint of cost, and the thickness of the SS material is 2.0 mm to prevent generation of intermetallic compounds and cracks.
mm or more is preferable.

As shown in FIG. 1, an anode rib (3)
Is formed into a shape having a bent portion (3a) in contact with at least one of the surfaces of the anode (1) and the anode pan (2), and the cathode rib (13) is similarly formed with the cathode (11) or the cathode rib (13). The cathode pan (12) is formed in a shape having a bent portion (13a) in contact with at least one surface. As described above, at least one end of the anode rib (3) and the cathode rib (13) according to the present invention includes:
A bent portion (3a) and a bent portion (13a) are formed, respectively. The shapes of the anode rib (3) and the cathode rib (13) are, for example, those shown in FIGS.
The shape may be an L shape, a U shape, a substantially Z shape, a substantially O shape, or the like as shown in FIG. In any case, the shapes of the anode rib (3) and the cathode rib (13) are not limited to those shown in the figures, and the anode (1) or the anode pan (2), or the cathode (11) or the cathode pan What is necessary is just to have a bent part which comes in contact with at least one of (12).

Next, the spot welding of each member will be described with reference to specific numerical examples.
The bent portion (13a) and the cathode pan (12) of
In the KA.5 cycle, joining was performed by direct spot welding (first welding), and further, at the same position as the first welding, a current 13 was applied to the SS member side of the cathode pan (12) and the clad plate (9).
Joining was performed by direct spot welding (second welding) in KA · 6 cycles. Subsequently, regarding the joining between the titanium side of the clad plate (9) and the anode pan (2), the titanium has a high electric resistance, and the current of 9 KA-7
In the cycle, joined by series spot welding (third welding), and at the same position as the third welding, the anode pan (2)
The bent portion (3a) of the anode rib (3) was joined by series spot welding (fourth welding) at a current of 8 KA for three cycles for the same reason as the third welding. Finally the anode (1)
And the anode rib (3) were joined by series spot welding at a current of 3 KA and 3 cycles, and the cathode (11) and the cathode rib (1) were joined.
3) was joined by series spot welding at a current of 6 KA for 3 cycles. The current and cycle, which are the welding conditions for the spot welding described above, are not particularly limited because they vary depending on the material and thickness of each member. Further, the third welding and the fourth welding can be performed simultaneously.

[0014]

As described above, in the unit electrolytic cell constituting the bipolar electrolytic cell according to the present invention, each member is joined by spot welding via a rib having a bent portion at at least one end. This ensures that welding can be performed uniformly under the same conditions in a short period of time, so there is no variation in electrical resistance and the amount of heat generated during welding is low. Never worry about the distortion. Therefore, the productivity of the assembly and processing of the electrolytic cell is improved, and a high-quality unit electrolytic cell, that is, a bipolar electrolytic cell can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing the periphery of an anode and a cathode in a unit electrolytic cell according to the present invention.

FIG. 2 is a schematic plan view showing another embodiment of an anode rib and a cathode rib.

FIG. 3 is a schematic cross-sectional view schematically showing almost the upper half of a conventional unit electrolytic cell.

FIG. 4 is a schematic plan view showing the periphery of an anode and a cathode in a conventional unit electrolytic cell.

[Explanation of symbols]

 Reference Signs List 1 anode 2 anode pan 3 anode rib 3a bent portion 4 anode chamber 5 gasket 6 upper (lower) frame 7 opening 8 expanded metal 9 clad plate 10 ion exchange membrane 11 cathode 12 cathode pan 13 cathode rib 13a bent portion 14 cathode chamber

Claims (3)

[Claims] 1. An electrolytic cell comprising: an anode rib and an anode pan forming an anode chamber; a cathode rib and a cathode pan forming a cathode chamber; and a clad plate disposed between the anode pan and the cathode pan. A bipolar electrolytic cell characterized in that an anode rib and an anode pan, an anode pan and a clad plate, a clad plate and a cathode pan, and a cathode pan and a cathode rib are respectively joined by spot welding. 2. A shape in which the anode rib has a bent portion in contact with at least one of an anode and an anode pan, and the cathode rib has a bent portion in contact with at least one of a cathode and a cathode pan. 2. The bipolar electrolytic cell according to claim 1, wherein the electrolytic cell is formed in the shape of a cell. 3. The method according to claim 1, wherein the clad plate is made of titanium having a thickness of 0.7 mm or less and rolled steel material for general structure having a thickness of 2.0 mm or more. Bipolar electrolytic cell.