JPS60110890A - Finger anode in bipolar alkaline chloride electrolyzer assembly unit - Google Patents

Abstract

PURPOSE:To prevent the increase in electrolytic cell voltage and decrease in current efficiency by attaching anode supports to the inside of U-shaped fingers of finger anodes to reinforce the fingers against external pressure. CONSTITUTION:The top end of each finger anode 4 is cut by a mechanical cutting method, etc. and the anode plate 4 of the anode 4 is bent outward in the position 9 at the prescribed length from the pat 8 to be joind to a power feed body 3. Two sheets of the plates 4 facing each other are expanded in such a way that the space from finger cathodes 6 seated opposite thereto is maintained within the prescribed adequate range in the case of using a cation exchange membrane 12 as a diaphragm. Anode supports 10 having approximately the same length as the overall length in the longitudinal direction of the plates 4 are welded longitudinally to the inside of the plates 4, 4. The top ends of the plates 4 are finally fixed at the prescribed space maintained therebetween via a bringing plate 11. The increase in the electrolytic cell voltage and the decrease in current density occuring in the depression of the hollow anodes 4 on receiving of pressure from the cathode chamber side via the membranes 12 on account of a difference in the specific gravity of liquid under electrolytic conditions are thus prevented.

Description

[Detailed Description of the Invention] Unexploded [Jj is an electrolytic cell assembly unit suitable for operating at a low cell voltage when using a cation exchange membrane in place of an asbestos diaphragm in an existing bipolar diaphragm electrolytic cell. Regarding finger anodes in.

A method for obtaining caustic alkali by dissolving alkali chloride in '11 From the viewpoint of pollution prevention, the mercury method was replaced by the diaphragm method using an asbestos diaphragm.Currently, this diaphragm method is used as the electrolytic method for aqueous alkali chloride solutions. It has become mainstream.

This diaphragm method electrolytic cell uses a large number of electrolytic cell units that are assembled and assembled together, and each electrolytic cell unit is connected to one end of the power supply rod that is connected to the partition wall through a cathode pack screen. The legs of a number of finger cathodes having a U-shape are welded to the other end of the electrode rod, and the legs of a number of finger anodes having a U-shape in horizontal cross section are welded to the other end of the electrode rod via a power supply body. ing. When the electrolytic cell units are joined and assembled together, the finger cathodes and finger anodes of adjacent units are inserted in a staggered manner to form a bipolar electrolytic cell (hereinafter referred to as one finger cell). Further, an asbestos diaphragm is attached and formed in a layer on the finger cathode. Note that the end unit of the electrolytic cell is provided with only either a finger anode or a finger cathode, and is assembled with the finger cathode or finger anode of the adjacent intermediate unit.

The finger 11 is made by bending a titanium plate formed into an expanded metal sheet so that its horizontal section forms a U-shape, and its both legs are welded to one power supply.The finger cathode is made of a mild steel wire. IJI'11
Is the department 1 entertainment back screen and salary? l'i',
-*i, '+ of 4'j'' is connected to VCC. NM
and said power supply rod i11.11. , Angle γb''/unit pasting IF, (through 9J1 to the anode box side, front 1
．． [Selected to be the power supply to which Schiffer is connected.]
λ, has been.

The hollow interior of the fingers 1i''54'pi formed across the asbestos 1'1°1~membrane and the wall gap between the partition wall and the cathode pack screen γ-1-8 J: Yin 4i; constitutes %j, The external side of the asbestos diaphragm, ie the side on which the finger anodes are located, constitutes the anode chamber Z).

Diaphragm method 1 using the existing asbestos constructed as above as a diaphragm → The caustic alkali obtained from tank decomposition has a low concentration and contains a large amount of alkali chloride as an impurity, so it is directly used for the rayon industry etc. It's hard to do that. On the other hand, it does not contain alkali chloride and K l
An ion exchange membrane method using a cation exchange membrane has been developed as an electrolytic method that can directly obtain a caustic alkali having an A1 degree.

Therefore, it is necessary to use the existing asbestos diaphragm method electrolytic cell and attach a cation exchange membrane to the finger cathode in place of the asbestos diaphragm. , it is possible to convert to ion exchange electrolysis without a large investment in equipment related to electrolyzers, and the industrial advantage is very large.

However, according to the studies conducted by the present inventors, when electrolyzing alkali chloride was carried out by attaching a cation exchange membrane to the cathode in place of the asbestos diaphragm to one of the fins in the single finger tank described above, the following results were obtained. I encountered a problem.

That is, despite the use of an ion exchange membrane, the cell voltage is very high, and therefore the current efficiency of the caustic alkali obtained from the cathode chamber is extremely low.

The inventors of the present invention conducted extensive studies to solve this problem, and as a result, it became clear that the cause of this problem lies in the anode structure. Under electrolytic conditions, the hollow finger anode receives pressure from the cathode chamber side through the liquid specific gravity cation exchange membrane. The distance is 2-3 compared to when the liquid is not filled.
The supply of alkali chloride into the anode chamber formed by the individual finger anodes, which are doubled in size and narrowed at the same time, becomes insufficient, leading to uneven alkali chloride concentration in the anode chamber of the electrolytic cell. It was found that this caused an increase in battery voltage and a decrease in current efficiency.

An object of the present invention is to solve the above problems and provide a finger anode that can maintain a stable and narrow anode-cathode distance during electrolysis and maintain a uniform alkali chloride concentration in the anode chamber. In particular, the finger anode L2 can be used by adding a simple modification to an existing one.

That is, the first invention has a structure of a finger positive plate that achieves the above-mentioned object, and has a large number of U-shaped water droplets at one end of the feed tilt frame connected to the partition wall through a cathode bank screen. Add the foot part of the finger cathode,
At the other end of the power supply rod, legs of a number of finger anodes having a U-shaped horizontal section are attached via a power supply body.
, in a unit for assembling a bipolar alkali chloride electrolytic cell, in which the finger cathode is equipped with a cation exchange membrane,
The anode having one fin is characterized in that a columnar anode support is vertically attached inside the U-shaped finger to reinforce against external pressure.

In addition, the second invention has a finger anode structure that is even more effective than the first invention, and has a U-shaped horizontal section at one end of the power supply rod connected to the partition wall through a cathode pack screen. The legs of a large number of finger cathodes are added to the other end of the power supply body, and the leg parts of a large number of finger anodes whose horizontal cross section is U-shaped are added to the other end of the power supply body. In a bipolar alkaline chloride electrolyzer assembly unit equipped with an ion exchange membrane, the tip of the finger 15III$p is cut in the longitudinal direction to form two anode plates, each of which is made up of two anode plates. The fin is bent outward at a position 10 to 5 Qmm from the mounting leg to the power supply body to enlarge it, and then the fin is attached at one place between the tip of the anode and the leg or v
Hollow anodes are placed vertically inside the finger so that the pinch is within 200 mm at several points. ), and is characterized in that the tips of the two monopolar plates are fixed together via a bridging plate.

To explain the embodiment of the present invention, the finger anode is formed by bending a titanium plate formed on an expanded mesh so that each horizontal side forms a ``1'' shape, and the legs of the finger anode are welded to the power supply body. ing. A column-shaped anode support i is added vertically to 1111 of this hollow finger threshold electrode, and the anode support is attached to both the tip of the finger 1 and the attachment part to the power supply body. mr
When inserting r (y, can be removed. Take two or more separated anode supports) on the inside of the finger so that the distance between adjacent anode supports is within 2 (JOmm), It can be seen inside the finger anode.

According to the study by Kinoe Machina et al., the /l-A of the finger anode
l11 +'llr JT-+-2+'Buddha Dawn t/J-+
-x4qc eight points: ++ Har-I-1t", y return If the distance to the m heating port is within 200mm, the dent in the anode plate will be 1.0 even against the pressure from the cathode chamber side. It becomes possible to press within the key.

This anode (sp) avoids problems such as the finger anode being dented inward by the pressure from the cathode chamber side through the cation exchange membrane, increasing the battery cell voltage, and insufficient supply of alkali chloride, and causing a low battery voltage. It becomes possible to operate at high cell voltage and high current efficiency.

Anode installed 7+? -The object of the present invention can be achieved even if the object is a hollow body such as a prism, a perforated plate, or an eclipse. A hollow columnar object with a diameter of 100 mm is preferable for lh.

In the case of this pipe, when attaching it to the finger anode, it is preferable to perform multiple joints by, for example, spot welding or TIG welding so that it is a point joint rather than a surface joint.

By making the anode support hollow, it can function as a downcomer that promotes the circulation of the electrolyte within the finger anode, helping to equalize the alkali chloride concentration within the electrolytic cell. Operation with high current efficiency becomes easy.

At this time, it promotes the downward flow of the electrolyte and further exerts its function as a downcomer.
It is preferable that there are no four colors.

Also, It? In order to narrow the distance rp;
The electrode finger is attached to the root D Vli: The finger 194 pole from the junction with the body to the position 10 to 5 otmn is expanded outward, that is, toward the cathode side, and the width is 1"14, and the support is cut into two pieces. When several anodes are placed between the anode plates, it is impossible to maintain the distance to the cathode with extreme precision.
Furthermore, it is preferable because the battery voltage can be reduced.

Next, a finger anode according to the present invention obtained by modifying an existing finger anode will be described with reference to the drawings.

FIG. 1 is a partial sectional view of a conventional bipolar diaphragm electrolytic cell taken horizontally and viewed from above. FIG. 2 is a perspective view of one of the many finger anodes.

A power supply body 3 is welded to a power supply rod 2 which is joined to a partition wall 1 made of mild steel whose inner surface on the side of the anode chamber is lined with titanium.
The power supply body 3 is provided with a finger-shaped anode 4 made of titanium expanded metal coated with an anode active material and processed into a U-shape.
The legs are welded. On the other hand, on the cathode side, the partition wall 1
A finger cathode 6 made of a net made of woven mild steel wire is welded to the cathode back screen 5 and the power supply rod 2 passing through the back screen 5 at a distance from the finger cathode 6 .

Usually, in the diaphragm method using asbestos as a diaphragm, the bag-shaped finger cathode 6 is covered with an asbestos diaphragm formed by digitizing asbestos slurry.

FIG. 3 is a sectional view showing an example of an anode obtained by modifying the U-shaped finger anode shown in FIGS. 1 and 2 according to the present invention, and FIG. 4 is a perspective view thereof.

In the present invention, first, the tip portion 7 of the finger anode is cut by a known method such as a mechanical cutting method or a gas cutting method. Next, the homopolar plate 4 of the cut finger anode as shown in FIG. The width of the two homopolar plates is widened so that the distance between the opposing finger holes falls within an appropriate predetermined range when a cation exchange membrane is used as a diaphragm. Next, an anode support 10 is placed inside the two anode plates 4, which have been cut 11yi at the tip and widened.
Take a few. The anode support 10 has approximately the same length as the entire length of the anode plate 4 in the vertical direction, and has several points or lines of contact with the anode plate, for example, by spot welding or TIG welding.

11', The three-pole Zaport 10 is a hollow cylindrical body as shown in Figs. 3 to 6 in order to promote the circulation of the liquid.
In addition, any material can be used as long as it has a 1 lul property for the anode chamber product. Among these, titanium, which is the same as , is preferred.

It is desirable that the inner surface of this j) 4-way, middle vertical part) is not coated with an anode active material. This is because no bubbles are generated on the inside of the cylinder, and the downcomer functions more effectively.

The anode support 10 attached to the inside of the anode plate 4 is placed within 200 mm from both the tip 7 of the finger anode and the joint 8 with the power supply body in order to prevent denting due to pressure from the cathode chamber side. At least 1 on the inside of the anode plate
More than one can be installed.

If the distance between the tip 7 of the finger anode and the joint 8 with the power supply body is within 400 degrees, it is preferable to attach the anode support 10 at a location corresponding to half the length of the finger anode. When two or more finger anodes are attached, it is preferable to attach them at positions that equally divide the length of the finger anodes.

Finally, the opposing anode plate 4 with the tip 7 cut off.
The tips of the cathode chambers 4 are fixed at a predetermined distance through a bridging plate 11 so that pressure from the cathode chamber side can be applied.

The bridge plate 11 is not particularly limited to a perforated plate or a flat plate,
Alternatively, it may be made of titanium exotic metal coated with anode active coating and having the same specifications as the anode. Also, is this part a current? [Because of its low strength, a frame made of chlorine-resistant resin may be used instead of metal. Gift exchange lxt
2 to the finger IQ 4/li 6 in advance and when assembling the finger-shaped anode and the electrolytic cell:
If you use a pre-plated gold plate or a frame made of Teflon or other plastic as a bridging board, you will be able to exchange ions! This is preferable because the chemical 1'l'r column can be assembled without damaging the 1j.:.

When alkali chloride is decomposed using a cation exchange membrane using a bipolar diaphragm method (tt'V) having the structure modified in this way, 19 steps are carried out through ion exchange. The distance between the anode and cathode was
It is much narrower than when using a membrane, and the fins are
The distance between the poles between the roots can also be made uniform, and a low 'tB 4Vi voltage can be achieved. In addition, several anode supports 11 are placed inside the finger anodes to prevent the finger anodes from being dented due to pressure from the cathode chamber side through the cation exchange membrane, and to maintain a predetermined distance of 41 cm. At the same time, by making the anode support hollow, it acts as a downcomer that promotes the circulation of the electrolyte in the finger anode, which helps to equalize the alkali chloride concentration in the anode chamber of the electrolytic cell, and allows operation with high current efficiency. It becomes possible.

Example Finger-shaped anode The tip of a finger-shaped anode made of 1/2-inch mesh titanium extract gundo metal coated with ruthenium oxide and has a U-shaped cross section with a side surface size of 1220 mm in height and 335 mm in length. was cut using a gas cutting machine, and a hJi curve was formed outward at a position 25 mm away from the joint of the anode plate welded to the power supply body. The cross-sectional size is 335 mm long.

The distance between the anode plates was widened so that the distance to the U-shaped bag-shaped finger cathode, which had a width of 16 mm at the tip and a width of 25 mm at the base, was 2.5 M. The inside of the central part of this anode plate has a length of 1220 mm and an inner diameter of 28 mm.

A titanium tube with an outer diameter of 31 mm was attached by TIG welding, and then the tips of the two cut anode plates were attached to a titanium plate with a thickness of 1.5 m and the surface smoothed in advance. They were fixed by TIG welding via a bridge plate with a length of 1220 mm that was manufactured by bending.

A bipolar diaphragm electrolytic cell with 44 finger cathodes and a modified anode as described above was equipped with a cation exchange membrane having a carboxyl acid group, and a 5-square box of saline solution was added. r
I did this.

World: The ion exchanger trq is formed into a bag shape in advance, and is placed over the bag-shaped finger cathode to form a cathode chamber.
At a vacuum of +1,120°C, the cathode chamber frame was assembled into the frame. Then, electrolysis of saline water is carried out under the following conditions.

1L37 force (t; ; 72kA Temperature; 90C Outlet 1"ηf1 soda i! 53 degrees; 32W% output [1
Ground water: 41 degrees: 200ft As a result, the electrical voltage is 3.37. It was stable for a long time at f-rut. In addition, the caustic acid 5+ obtained from the cathode chamber side
The efficiency was also stable at 95.5%.

Comparative Example 1 Prefecture / 7'' 1 ~ 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 2000 x 100 x 100 x 100 x 100 x 100 x 200 x 100 x 200 for hrN Version

As a result, the electric wire voltage gradually increased after the start of operation, and the electric wire voltage stabilized at 3.63 z. In addition, the current efficiency of caustic soda from the cathode chamber side is as low as 92.5%, and the concentration of oxygen in chlorine obtained from the anode chamber is also lower than in the example.
It showed a value higher than Vol'%.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view of an existing bipolar diaphragm electrolytic cell. FIG. 2 is a perspective explanatory view of an existing anode structure. FIG. 3 is a cross-sectional explanatory diagram of a finger anode according to the present invention. FIG. 4 is a perspective explanatory view of the finger anode. FIG. 5 shows the anode 4 in the present invention. - FIG. FIG. 6 is an explanatory cross-sectional view of a bipolar diaphragm electrolytic cell in which the cation exchange membrane of the present invention is set. 1: Partition wall 2: Power supply rod 3: Power supply body 4: Anode 5: Cathode back screen 6: Fingani cathode 7: Finger anode tip 8: Anode end and joint with power supply body 9: Anode plate widened part lO: Anode support 11: Crosslinked plate 12: Cation exchange membrane. I Figure 1 Ii> 2nd Figure 3 1゛j 4 Figure-A

Claims (1)

[Claims] 1. A multi-finger cathode leg portion having a U-shaped horizontal cross section is attached to one end of the power feeder joined to the partition wall through a cathode pack screen, and the legs of a multi-finger cathode having a U-shaped horizontal section are attached to the other end of the power feed rod. This is a detachable type electrode control system, in which the legs of a number of finger anodes, each of which has a U-shaped horizontal cross section, are attached via a power supply body, and a type 1 ion exchange membrane is attached to the finger cathodes. In the assembly unit, the finger It!
The pole is a columnar anode inside the U-shaped finger. −
This finger anode is characterized by several lengthwise edges that are reinforced against external pressure. 2. Claim 1, characterized in that the 1X electrode support is attached at one or more locations between the tip and leg of the finger anode, and the pitch is within 200 m18. Finger anodes as described in Section. 4. The finger anode according to claim 3, wherein the hollow inner surface of the hollow anode support is made of a material having no anode activity. 5. The finger anode according to claim 1.2.3 or 4, wherein the finger anode is widened outward at a position 10 to 50 fi from the mounting leg for the power supply body. . 6. At one end of the power supply rod connected to the bulkhead, a large number of fins with a U-shaped horizontal section are attached to one cathode leg through a cathode pack screen, and at the other end of the power supply rod, a power supply body is attached. In the unit for assembling a bipolar alkali chloride electrolytic cell, the leg portions of a number of finger anodes having a U-shaped horizontal cross section are taken through the same, and a cation exchange membrane is attached to the finger cathodes. The tip of the finger anode is cut vertically to form two anode plates, and each anode plate is separated from the mounting leg to the power supply body by 10 to 59 m.
The width of the anode is expanded by bending it outward at the position m, and then a hollow anode is formed in the longitudinal direction inside the finger so that the pitch is within 200 at one or more places between the tip and the leg of the finger anode. Attach the support and place the tips of the two anode plates together! A finger anode characterized in that it is fixed through an l plate. 7. The finger anode according to claim 6, wherein the hollow inner surface of the hollow anode support is made of a chlorine-resistant material η having no anode activity.