JPH0437905Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a metal extraction device that can control the fluctuation in the height of the electrolyte due to the gas generated near the electrode when metals such as copper, nickel, and cobalt are electrowinning. It is something. [Prior art] When extracting metals such as copper, nickel, and cobalt by electrowinning, a large number of anode plates and cathode plates are arranged alternately in a long and narrow electrolytic tank, and electrolysis is performed to collect metals such as copper, nickel, and cobalt. The desired metal is deposited on the electrolytic bath, and when the desired thickness is reached, it is taken out from the electrolytic bath and used as a product. In this case, in the electrolytic treatment method using an insoluble anode, gas is generated on the anode plate, and this gas not only diffuses into the air from the electrolyte surface, but also solid particles floating in the electrolyte. It also accompanies it and scatters it into the air. Therefore, if the electrolytic solution is, for example, a chloride solution, the gas generated is chlorine gas, which is harmful, and cannot be left as it is for other purposes. Various control means and recovery means have been proposed. Among these, there is a means for enclosing most or all of the insoluble anode plate in an almost airtight manner and storing it in an insulating box with a diaphragm on the side, and sucking and recovering gas generated from the anode during electrolysis. have been proposed (for example, Utility Model Publication No. 51-22855,
Special Publication No. 57-15674). In other words, the device of Special Publication No. 57-15674 is
As shown in Fig. 5, an insoluble anode plate 1
is placed in an anode box 2 on which a diaphragm 4 is stretched so as to have an appropriate distance between it and the outer surface thereof, and is suspended from a crossbar 6 electrically connected to a busbar 5, and a cathode plate 9 They are placed alternately in the electrolytic cell 8 so as to face each other parallel to each other. moreover,
The anode box 2 is provided with an exhaust branch pipe 12 for discharging generated gas accumulated in the anode box.
An exhaust suction line 10 is formed which is connected to a main exhaust pipe 11 that collects the exhaust gas from each anode box 2. A siphon-shaped drain line 13 is formed by connecting drain branch pipes 15 extending upward from the bottom of the drain pipes 2 .
Therefore, when performing the electrolytic operation while supplying a certain amount of electrolyte, the generated gas is exhausted by suctioning through the exhaust suction line 10 so that the pressure inside each anode box 2 is slightly lower than atmospheric pressure. At the same time, the electrolytic solution enters the anode box 2 through the diaphragm 4, and the electrolytic solution subjected to the electrolytic treatment is discharged to the outside through the drain line 13, and metal is deposited on the cathode plate 9. . [Problems to be solved by the invention] However, in the case of such a conventional device, as mentioned above, the air is sucked and exhausted through the exhaust suction line to maintain the pressure inside the anode box slightly lower than atmospheric pressure. At this time, each time the pressure inside the anode box fluctuates due to blockage of the exhaust suction line with electrolyte, etc., the height of the liquid inside the anode box fluctuates, and this effect causes the liquid level on the cathode side, that is, the electrolytic cell, to rise. As a result, the liquid level in the electrolytic cell sometimes becomes below the lower end of the upper frame of the anode box, and the state continues in which air near the anode box installation position is sucked through the diaphragm surface provided on the anode box. Sometimes. In this case, if the recovered gas is, for example, chlorine gas and is used as an oxidizing agent, the concentration of the recovered chlorine gas will decrease, and the product being processed will be affected by the uneven concentration. It will also have a negative impact. In addition, when the electrolyte level is returned to the top of the upper frame of the anode box after atmospheric air has been sucked in, a circulation occurs in which the solution containing gases generated in the anode box, such as chlorine gas, flows back toward the electrolytic cell. When this phenomenon occurs, a large amount of gas is released from the liquid level of the electrolytic cell whose top is open, contaminating the working environment, and the unstable liquid level of the electrolytic cell causes electrodeposit to form on the cathode. There were problems such as making it easier to cause non-uniform defects. The present invention aims to solve the above-mentioned problems and provide a means for reducing fluctuations in the electrolytic cell liquid level. [Means for Solving the Problems] In order to solve the above problems and achieve the above objectives, the inventors of the present invention have repeatedly devised ways to connect one end of the exhaust suction line for suctioning generated gas with one end inside the electrolytic cell. Recognizing that the purpose could be achieved by connecting the other end of the water-sealed tube immersed below the gas-liquid interface so that the inside of the anode box and the liquid surface of the electrolytic cell could be simultaneously sucked, the present invention was devised. I was able to complete it. That is, the present invention provides an anode box in which an exhaust suction line for suctioning generated gas is provided in the electrolytic cell, a siphon-shaped drain line is further provided for draining the electrolyte, and an electrolyte permeable diaphragm is provided on the side surface. In an electrolysis device for metal extraction, in which a plurality of flat insoluble anode plates and a plurality of cathode plates housed in an electrolytic cell are installed facing each other alternately, the ends are immersed below the gas-liquid interface in the electrolytic cell. This is an electrolytic device for metal extraction, in which the other end of a water seal tube is connected to an exhaust suction line for suctioning generated gas. Next, a configuration example of the device of the present invention will be explained based on the attached drawings. Fig. 1 is a sectional view in the width direction showing an embodiment of the device of the present invention, Fig. 2 is a sectional view of the main part in the longitudinal direction, and Fig. 3 is a perspective view of the main part with a part cut away. be. 1 is an anode plate made of a flat insoluble material such as a metal plate or a zinc plate, and made of a corrosion-resistant electrical insulator such as fiber-reinforced plastic to have a shape almost similar to that of the anode plate 1. A window 3 is provided, which is slightly larger than the anode plate 1, and a diaphragm 4 made of a sufficiently dense material is stretched, which allows the electrolyte to pass through from the electrolytic cell, but does not allow the gas generated on the anode plate 1 to pass through. A crossbar 6 is inserted into a certain anode box 2 with an appropriate distance between the outer surface of the anode plate 1 and the inner surface of the anode box 2, and is electrically connected to a busbar 5 connected to a power source (not shown). , are fixed to the introduction support rod 7 and suspended, and arranged in the electrolytic cell 8. Reference numeral 9 denotes a cathode plate, which is made of a metal thin plate such as copper, nickel, cobalt, etc., and is electrically connected to the bus bar 5 and suspended in the electrolytic cell 8, facing parallel to the anode plate 1. It's hanging. 10
is the exhaust suction line, and each anode box 2
Exhaust main pipe 11 that collects exhaust gas from the exhaust main pipe 1
1 and an exhaust branch pipe 12 that opens into the anode box 2 and absorbs and exhausts generated gas that accumulates in the upper part of the anode box 2. Reference numeral 13 denotes a drain line, which is connected to a drain main pipe 14 arranged in the longitudinal direction of the bottom of the electrolytic cell 8, rising along the side wall, and descending beyond the side wall. The anode box 2 has a siphon-like configuration with a drainage branch pipe 15 that penetrates through the bottom of the anode box 2 and opens near the top end, and is designed to discharge the electrolyte that has undergone electrolytic treatment in the anode box 2 during electrolysis operation. . 16
is a water-sealed tube made of corrosion-resistant material such as vinyl chloride, and has one end immersed below the gas-liquid interface in the electrolytic cell 8 and the other end connected to the main exhaust pipe 11 of the exhaust suction line 10. They are formed so as to be connected and are installed between each pole. The side to be immersed in the electrolytic solution is made into a bowl shape with an inner diameter of about 50 mm at the opening, immersed face down in the electrolytic solution, and a pipe with an inner diameter of about 13 mm is connected to the main exhaust pipe 11 on the bottom side. . Therefore, it is preferable that the immersion depth when immersing the end of the water seal tube 16 in the electrolyte is set to 15 to 25 mm.
If the immersion depth is too shallow, the water seal tube 16 will separate from the electrolyte due to fluctuations in the electrolyte level, making it ineffective. If the immersion depth is too deep, more power will be consumed than necessary for the suction force of the generated gas. It is something that makes you Since the device of the present invention is configured as described above,
In starting the electrolytic operation, first, a predetermined number of anode plates 1 and cathode plates 9 are placed alternately in the electrolytic cell 8 so as to face each other in parallel at a predetermined interval, and a water seal tube 16 is placed between each electrode. When the electrolytic solution is supplied from a supply pipe (not shown), the electrolytic solution level in the electrolytic cell 8 rises and the electrolytic solution enters the anode box 2 through the diaphragm 4, and the electrolytic solution enters the anode box 2 through the diaphragm 4. The electrolyte level also rises in the same way, and when it crosses the drainage branch pipe 15, it overflows and becomes almost the same as the electrolyte level in the electrolytic cell 8. At this time, it is desirable to provide a drain 17 at a point where the main drain pipe 14 crosses the side wall of the electrolytic cell 8 at approximately the same height as the upper end of the branch drain pipe 15. In this state, operation is started while supplying a constant amount of electrolyte, and the anode box 2 and water seal tube 1 are
When electrolysis is performed while suctioning and exhausting 6 through the exhaust suction line 10 to a pressure slightly lower than atmospheric pressure, some of the gas generated on the surface of the anode plate 1 in the anode box 2 will dissolve in the electrolyte. Most of it floats in the electrolyte and is sucked into the gas suction line 10 and discharged, collected in a buffer tank (not shown), and used for the next use. On the other hand, the electrolytic solution rises to a height commensurate with the negative pressure caused by the suction, so it overflows from the drainage branch pipe 15, and new electrolytic solution permeates through the diaphragm 4 to be supplied, and the electrolysis operation is continued. During this time, the upper part of the liquid level in the anode box 2 and the gas layer above the liquid level in the electrolytic cell 8 are being sucked in at the same time. On the other hand, in this device, there is a large difference between the liquid level height in the anode box 2 and the liquid level in the electrolytic cell 8 so that the maximum liquid level fluctuation width can be suppressed to about 25 mm. This can be prevented from occurring. [Example] Next, an example of the present invention will be described. Example: In an anode box with an electrolyte-permeable diaphragm stretched as a diaphragm, 8 anodes containing anode plates of metal base electrodes as insoluble electrodes and 7 cathode plates of nickel thin film of 800 x 1000 mm were installed as specified. volume
Using a 1700 electrolytic cell, between each electrode, a water seal tube with an inner diameter of 50 mm was connected to the main exhaust pipe of the exhaust suction line for suctioning generated gas with one end of a 13 mm inner diameter pipe made of vinyl chloride placed below the surface of the electrolyte. Immersion depth of 5mm, 15mm, 25mm
While supplying a 15wt% nickel chloride solution as the electrolyte at a rate of 590ml/min per anode box, the cathode current density was 3.3V DC.
Continuous operation was carried out for 8 days under the condition of 2.3A/ ^dm2 . During operation, fluctuations in the electrolyte level and composition of recovered gas were measured every 8 hours. These results are shown in the following table for the 2nd, 5th, and 8th days, with the liquid level fluctuation representing the maximum fluctuation value and the gas composition representing the average composition. The gas composition analysis was performed according to the JIS 2301 fuel gas Hempel analysis method, especially for chlorine content, using 300 g of KOH/solution. Comparative Example Except for not using a water seal tube, the same equipment as in the example was used, the operation was carried out under the same conditions as in the example, and the same measurements as in the example were performed. The results are also shown in the table below.

【table】

[Table] As described above, it is recognized that the device of the present invention can collect recovered gas in a stable manner with a high concentration. In contrast, in the conventional device that does not use a water seal tube, the chlorine content was 88% of the Example on the second day, 82% on the fifth day, and only 65% on the eighth day. [Effects of the invention] The present invention is equipped with a water-sealed tube that connects one end to the exhaust suction line and immerses the other end in the electrolytic solution. It is possible to extremely reduce fluctuations in the concentration of generated gas, to prevent unnecessary circulation of the electrolyte from the anode box to the electrolytic cell, and to stabilize the quality of the product collected at the cathode. It has been recognized that there are significant effects, including a significant contribution.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view in the short direction showing an embodiment of the device of the present invention, FIG. 2 is a cross-sectional view in the longitudinal direction, FIG. The figure is a sectional view in the short direction of the conventional example, and FIG.
It is also a sectional view in the longitudinal direction. 1... Anode plate, 2... Anode box, 4... Diaphragm, 8... Electrolytic cell, 9... Cathode plate, 10... Exhaust suction line, 11... Exhaust main pipe, 12... Exhaust branch pipe, 13 ... Drain line, 14 ... Drain main pipe, 1
5...Drainage branch pipe, 16...Water seal pipe.

Claims (1)

[Scope of utility model registration request] An exhaust suction line for suctioning generated gas is provided in the electrolytic cell, and a siphon-shaped drain line is further provided for draining the electrolyte. In an electrolysis device for metal extraction, in which a flat insoluble anode plate and a plurality of cathode plates are installed alternately facing each other,
An electrolytic device for metal extraction, in which the other end of a water-sealed tube whose end is immersed below the gas-liquid interface in an electrolytic cell is connected to an exhaust suction line for suctioning generated gas.