JPS59162286A - Electrolytic cell using ion exchange membrane process - Google Patents

Abstract

PURPOSE:To form a caustic alkali having high purity and high concn. by housing the finger-shaped cathodes of a diaphragm process electrolytic cell into bag- shaped molding bodies consisting of cation exchange membranes, and grasping the base end parts thereof by the sealing materials in the spaces formed of adjacent cathode base parts and cathode mounting plates and elastic bodies in tight contact therewith. CONSTITUTION:Finger-shaped cathodes 9 of a conventional finger type electrolytic cell are housed in bag-shaped moldings 27 consisting of cation exchange membranes. The base ends of such moldings 27 are grasped by the sealing materials 19 which are formed of adjacent base parts of the cathodes 9 and cathode mounting plates 12 and are installed in the space and elastic bodies 26 adhered tightly to the materials 19. The diaphragm process electrolytic cell is thus converted to an electrolytic cell using ion exchange membrane process having an excellent structure while making effective use of the respective members of the diaphragm process electrolytic cell.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion-exchange removal electrolytic cell having finger-shaped electrodes, which makes it possible to produce high-purity, high-concentration caustic alkali.

As shown in FIG. 1, the conventional finger-shaped electrolytic cell has a plurality of finger-shaped cathodes A fixed to a cathode mounting plate and a plurality of finger-shaped anodes B fixed to an anode mounting plate. Finger-shaped anode B whose tips are adjacent to each other
The finger-shaped anode B is housed in a unit electrolytic cell C so that the tip of the finger-shaped anode B is located close to the base end of the adjacent finger-shaped cathode A.
It is divided into an anode chamber and a cathode chamber by a porous neutral diaphragm made of asbestos or the like coated on the surface of the chamber.

Then, an aqueous alkali halide solution is supplied to the anode chamber of the electrolytic cell, so that chlorine is obtained in the anode chamber, and caustic alkali and hydrogen are obtained in the cathode chamber.

However, in this conventional finger-type electrolytic cell, the porous neutral diaphragm that separates the anode and cathode chambers cannot prevent the back diffusion of chlorine ions from the anode chamber to the cathode chamber, so chlorine ions are generated in the cathode chamber. The drawback is that alkali chloride is mixed into the caustic alkali, reducing product purity.

The present invention aims to provide an electrolytic cell having a structure suitable for modifying a diaphragm method finger-type electrolytic cell that has been used in a conventional manner to create an ion exchange membrane method electrolytic cell partitioned by a cation exchange membrane. This invention provides an electrolytic cell with an excellent structure that can effectively utilize the equipment of a diaphragm finger type electrolytic cell and produce high-purity, high-concentration caustic alkali.

That is, in the present invention, a plurality of finger-shaped cathodes fixed to a cathode mounting plate and a plurality of finger-shaped anodes fixed to an anode mounting plate are arranged so that the tips of the finger-shaped cathodes are close to the proximal ends of the adjacent finger-shaped anodes. In an electrolytic cell in which the finger-like anode is housed in a unit electrolytic cell so that the tip of the finger-like anode is located near the proximal end of the adjacent finger-like cathode, the finger-like cathode is placed in a bag-like shape made of a cation exchange membrane. A sealing material housed in the molded body and placed in the outer surface space of the adjacent finger-shaped cathode base in parallel with the cathode mounting plate, and an elastic body brought into close contact with the sealing material. This is an ion-exchange dehydration electrolytic cell that is clamped and fixed by

The present invention will be described below according to embodiments shown in the drawings.

FIG. 2 is a partially cutaway longitudinal cross-sectional view showing an embodiment of the ion exchange dehydration electrolyzer according to the present invention, and FIG. 5 is the nl of FIG.
-1-line cross-sectional view; Figure 4 is a cross-sectional view of the main part of Figure 3;
Figure 5 is a cross-sectional view of the V-V fiber in Figure 6;
Figure 7 is an exploded perspective view showing the state in which the cation exchange membrane has been removed from the finger-shaped cathode, and Figure 8 shows the flow state of the circulating caustic alkaline solution in the lower part of the cathode chamber. FIG. 2 is a partially cutaway perspective view.

The electrolytic cell body 1 is composed of a plurality of unit electrolytic cells 2, and each unit electrolytic cell 2 is composed of side plates 3, a bottom plate 4, and a top plate 5. Each unit electrolytic cell 2 is provided with a partition plate 7 whose edges are in close contact with both side plates 3, a bottom plate 4, and a top plate 5, and in which a large number of circular holes 6 are bored. It is divided into 2 and the same number of electrolysis chambers. A cylindrical connecting tube 8 is fitted into the circular hole B of the partition plate 7, and one end (the right end in FIG. 3) of the connecting tube 8 is connected to the base end of a finger-shaped cathode 9 made of an integral bag-shaped mesh. It is fixed to the inner part of the vicinity by welding or the like. The base end of each finger-shaped cathode 9 has a circular hole 10 through which the connecting cylinder 8 passes, and an elongated hole 11 for smoothing the flow of catholyte at a location corresponding to each finger-shaped cathode 9.
are attached to a cathode mounting plate 12 made of a mesh plate with holes vertically perforated alternately, connecting each finger-shaped cathode 9. In addition, 13 is a reinforcing plate interposed between the partition plate 7 and the cathode mounting plate 12, and 14 is a finger-shaped cathode 9.
This is a reinforcement installed inside.

An anode mounting plate 15 made of a mesh plate is fixed to the other end (left end in FIG. 6) of the connecting tube 8 by welding or the like. A plurality of finger-shaped anodes 16 are fixed by welding or the like. The finger-shaped anode 16 is arranged in the electrolytic cell so that its tip is located between the base ends of adjacent finger-shaped cathodes 9, and the tip of the finker-shaped cathode 9 is located between the base ends of adjacent finger-shaped anodes 16. It is installed inside the main body 1.

The base end portion of the finker-shaped cathode 9 has semi-elliptic holes 17 on both sides with a diameter slightly larger than that of the finger-shaped cathode 9, and the edge of the semi-elliptic hole 17 is located at the tip of the finger-shaped cathode 9. A sealing material 19 having a bent portion 18 tapered in the direction is attached, and by bringing the side ends of the two sealing materials 19 into contact, an oblong hole having a larger diameter than the finger-shaped cathode 9 is formed. 20 is formed. The sealing material 19 has an elongated hole 21 having a larger diameter than the elongated hole 20 at a location corresponding to the elongated hole 20 of the sealing material 19 from the right side (FIG. 3).
A separating plate 22 having a perforated hole is adjacent to the separating plate 22, and a vertically elongated portion between adjacent oblong holes 21 of the separating plate 22 is located between adjacent bent portions 18 of the sealing material 19, and is fixed with a bolt 23. The elongated hole 2 of the separation plate 22 is provided in the vertically long part of the separation plate 22.
1, the peripheral edge of the oval hole 24 is bent in the direction of the sealing material 19 to form a bent part 25, and the outer surface thereof is tapered and deviates. The bent portions 25 of the adjacent oblong holes 24 of the body 26 are elastically fitted from the outside.

The finger-shaped cathode 9 is housed in a bag-like molded body 27 made of a cation exchange membrane, and the bag-like molded body 27 has its proximal end connected to the inside of the bent part 18 of the sealing material 19 and the folded part of the elastic body 26. It is fixed by being sandwiched between the outer sides of the curved portion 25. The unit electrolytic cell 2 is divided into an anode chamber and a cathode chamber by this bag-shaped molded body 27.

The top plate 5 of the unit electrolytic cell 2 is bent upward near the side edge of the anode chamber, and an alkali chloride aqueous solution supply port 28 is formed. An alkali chloride aqueous solution supply pipe 29 whose upper end is open in the shape of a funnel is installed in the supply port 28 , and the lower end of the supply pipe 29 reaches near the bottom plate 4 of the unit electrolytic cell 2 . A gas take-off pipe 60 is provided in an upward direction on the top plate 5 of the unit electrolytic cell 2 at a location opposite to the supply port 28, and is adapted to take out chlorine generated in the anode chamber.
An auxiliary pipe 61 is connected to the side plate 6.

An auxiliary pipe 36 facing in the same direction as the auxiliary pipe 30 is connected below the anolyte liquid level 32 of the side plate 3 on the side of the gas extraction pipe 30 of the unit electrolytic cell 2, and both auxiliary pipes 31, 33, An anolyte extraction tube 34 whose upper and lower ends are once bent in the same direction.
are connected to each other. Anolyte liquid level 6 of anolyte extraction pipe 34
2, there is an anolyte outlet 35 facing outward.
The anolyte is taken out from the anolyte outlet 65 and recycled as necessary.

Figures 5 and 6 are cross-sectional views of the cathode chamber, showing the unit electrolytic cell 2.
A gas extraction pipe 66 is connected to the side edge of the top plate 5 to extract hydrogen gas generated in the cathode chamber.

A catholyte outlet 38 is connected to a portion slightly below the gas outlet pipe 56 and corresponding to the catholyte level 37, and is adapted to take out the caustic aqueous solution produced in the cathode chamber.

Cathode chamber compartment! A conduit 39 for circulating a caustic alkali solution, one end of which passes through the side plate 3 and reaches the outside of the unit electrolytic cell 2, is installed in the lower part of the space between the cathode mounting plate 12 and the conduit 59. Oval hole 1 of the cathode mounting plate 12 on the top surface
A small hole 40 is bored at a location corresponding to 1. A base end portion of a guide plate 41 whose upper part is curved toward the cathode mounting plate 12 side is fixed to the cathode side surface of the partition plate 7 corresponding to the lowermost oblong hole 11 of the cathode mounting plate 12. The tip of the guide grate 41 is fixed to the upper edge of the lowermost oblong hole 11 of the cathode mounting plate 12 .

When an alkali chloride water bath solution is supplied to the anode chamber of the ion-exchange deprocessing electrolytic cell of this embodiment having such a configuration through the supply pipe 29, the cathode chamber is filled with water or a dilute aqueous alkaline solution, and electricity is applied from the anode side. The alkali metal ions in the anode chamber pass through the bag-shaped molded body 27 made of a cation exchange membrane and move to the cathode chamber to produce a caustic alkaline aqueous solution, which is taken out from the catholyte outlet 68. In this case, a cation exchange membrane that does not allow anions to pass through is used as a diaphragm, so chlorine ions will not be mixed into the produced solution.
The purity of the caustic alkali in the produced solution is improved. This produced solution may be used as a product as it is, but as shown in Figures 5 and 8.
The concentration of caustic alkali may be improved by circulating a part or all of the electricity shown in the figure through the circulation conduit 39. In this case, the caustic aqueous solution supplied to the lower part of the cathode chamber is passed through the finger It is fed into the shaped cathode 9 and mixed with the dilute solution to form a uniform height fl.
k rl An aqueous caustic solution can be obtained.

Further, from below the anolyte liquid level 32 in the anode chamber, an auxiliary pipe 36
Since the anolyte is taken out by the anolyte take-out pipe 34, the anolyte is not taken out in a gas-liquid mixed state, and chlorine is not mixed into the taken out liquid.

In the above example, an anode with an open tip was used, but when attaching this anode to the electrolytic cell, the tips of the anodes are tied together with a thread or the like to close the opening, and then the anode is attached with a thread or the like. In order to protect the cation exchange membrane, it is desirable to cut it or to electrolyze it as it is to dissolve the thread etc. in the anolyte to obtain the state as in the above embodiment. Note that the anode and cathode used in the present invention are not limited to the above embodiments; for example, various types such as a bag-shaped anode, a cathode with open top and bottom ends and a cathode, and electrodes other than Metsushi may be used. Can be done.

The cation exchange membrane used in the present invention can be made of any material as long as it has resistance to a highly concentrated caustic alkali aqueous solution and selectively allows only cations to pass therethrough. It is preferable to use perfluorocarbon polymers having sulfonic acid groups and sulfonic acid groups. Also,
In the above embodiment, the bag-shaped molded bodies 27 in the same number as the finger-shaped cathodes 9 were attached to the electrolytic cell without being connected to each other. It may also be an ion exchange membrane.

Further, the sealing material 19 and the elastic body 26 that seal the base end of the bag-shaped molded body 27 may be any material as long as they can prevent mixing of the anolyte and the catholyte, and the above-described implementation is performed as a material that fulfills the role of the elastic body. For example, the elastic body 26 and separation plate 23 may be used in combination, or the elastic body may be used alone.

The electrolytic cell according to the present invention houses the finger-shaped cathode of a conventional finger-type electrolytic cell in a bag-like molded body made of a cation exchange membrane, and the base end of the bag-like molded body is connected to the adjacent cathode base. A sealing material installed in the space formed by the and cathode mounting plate, and an elastic body tightly attached to the sealing material,
It is suitable for converting conventionally used diaphragm method electrolyzers into ion exchange farming electrolyzers. That is, in a conventional diaphragm electrolytic cell using an asbestos-based neutral diaphragm, a bag-shaped cathode is covered with an asbestos-based diaphragm to form a cathode chamber inside. It is possible to convert the diaphragm method electrolytic cell into an ion exchange farming electrolytic cell with an excellent structure while effectively utilizing each member.

In addition, since the base end of the bag-shaped molded body is firmly sealed with a sealing material and an elastic body, there is no leakage of the anode chamber solution and cathode chamber solution, and a high-purity caustic alkaline solution can be reliably produced. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an example of a conventional finger-type electrolytic cell, FIG. 2 is a partially cutaway longitudinal sectional view showing an example of an ion exchange farming electrolytic cell according to the present invention, and FIG. The diagram is
Fig. 4 is a cross-sectional view of the main part of Fig. 3, Fig. 5 is a vertical sectional view taken along line v-M of Fig.
The figure is a vertical sectional view taken along the line Vl-M in Figure 5, Figure 7 is an exploded perspective view showing the bag-shaped molded body removed from the finger-shaped cathode, and Figure 8 is the circulation in the lower part of the cathode chamber. FIG. 2 is a partially cutaway perspective view showing the state of flow of caustic solution. 1... Electrolytic cell body 2... Unit electrolytic cell 7... Division plate 9... Finger-shaped cathode 12... Cathode mounting plate 15... Anode mounting plate 16... Finger-shaped anode 19. ... Seal material 26 ... Separation plate 26 ... Elastic body 27 ... Bag-shaped molded body Fig. 1

Claims (10)

[Claims] (1) A plurality of finger-shaped cathodes fixed to a cathode mounting plate and a plurality of finger-shaped anodes fixed to an anode mounting plate are arranged such that the tips of the finger-shaped cathodes are located near the base ends of adjacent finger-shaped anodes. In an electrolytic cell in which the finger-shaped anode is housed in a unit cell so that the tip of the finger-shaped anode is located near the base ends of adjacent finker-shaped cathodes, the finger-shaped cathode is placed in a bag-shaped molded body made of a cation exchange membrane. The proximal end of the bag-like molded body is held between a sealing material installed parallel to the cathode mounting plate in the outer space of the adjacent finger-shaped cathode base and an elastic body in close contact with the sealing material. An ion-exchange dehydration electrolytic cell that is characterized by the following. (2) The ion-exchange removal electrolytic cell according to claim (1), wherein the finker-like cathode is hollow mesh-like. (3) The ion exchange deprocessing electrolytic cell according to claim (1) or (2), wherein the finger-shaped anode has a mesh-like shape with an open tip. (4) Claims (1) to (2) in which holes are formed in the cathode mounting plate at the base end of the finger-shaped cathode.
The ion-exchange membrane method decomposition tank according to any one of 5). (5) Claim (1) wherein the elastic body and the sealing material are plates each having an oblong hole, and the peripheral edges of both the oblong holes are provided with bent portions facing each other. The ion exchange dehydration electrolytic cell according to any one of paragraphs to paragraphs (4). (6) The sealing material is a combination of a plurality of unit members having semi-elliptical holes on the left and right sides.
5) The ion exchange dehydration electrolytic cell described in item 5). (7) Any one of claims 1 to 6, wherein the elastic body and the sealing material are fixed by bolts screwed together from the cathode mounting plate side of the sealing material. The ion exchange dehydration electrolytic cell described in . (8) The proximal end of the bag-shaped molded body is sandwiched between the inner surface of the bent portion of the sealing material and the outer surface of the bent portion of the elastic body. 7) The ion exchange dehydration electrolytic cell according to any one of items up to 7). (9) Claim (8) wherein the outer surface of the bent portion of the elastic body and the sealing material are tapered, and the proximal end of the bag-shaped molded body is sandwiched between a portion of both tapers. The ion exchange dehydration electrolytic cell described in . (10) The ion-exchange deprocessing electrolytic cell according to any one of claims (1) to (9), wherein the base ends of each bag-shaped molded body are connected to each other and are integrated.