JPH0285396A - Electrolytic treatment method and apparatus - Google Patents

Abstract

PURPOSE:To inhibit the vibration of a strip and to electrolytically treat the strip at low voltage and high current density when the strip is passed through a cylindrical electrolytic cell provided with electrodes at the inside and an electrolytic soln. is spouted parallel to the surface of the strip to electrolytically treat the strip, by placing an electrolytic soln. vessel communicating with the outlet of the electrolytic cell and enabling the regulation of the level of the soln. in the vessel. CONSTITUTION:A strip 2 is passed through a cylindrical electrolytic cell 1 provided with electrodes 3 at the inside and voltage is impressed between the electrodes 3 and the strip 2 while spouting electrolytic soln. parallel to the surface of the strip 2 from the nozzles 4 of headers 6 set at the inlet of the cell 1 to electrolytically treat the strip 2. In this case, an electrolytic soln. vessel 7 communicating with the outlet of the cell 1 is placed, the surface of the electrolytic soln. in the vessel 7 is kept higher than the top of the outlet of the cell 1 and the height of the surface of the electrolytic soln. in the vessel 7 is regulated with an overflow pipe 8. Since static pressure is applied to the strip 2 passing through the cell 2, the vibration of the strip 2 is prevented, the interval between the strip 2 and each of the electrodes 3 can be narrowed and the strip 2 can be electrolytically treated at low voltage and high current density.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electrolytic treatment method and apparatus for electrolytically treating a strip.

<Prior Art> Conventionally, electrolytic treatment apparatuses have been proposed that are capable of electrolyzing at high current density during electrolytic treatment and are capable of low voltage operation.

Japanese Patent Publication No. 50-8020 discloses that, as shown in Fig. 7, an electrolytic solution is injected onto a strip 2 passing through a cylindrical electrolytic cell 1 in a direction opposite to the traveling direction of the strip 2, thereby reducing the relative relationship of the strip 2 to the electrolytic solution. The speed was increased to enable electrolysis at high current densities. However, when this device is used, it is not effective in stably passing the strip 2, the distance between the strip 2 and the electrode 3 cannot be shortened, and when electrolysis is performed at a high current density, the voltage increases.

Also, if the passing speed of the strip 2 is low, the electrolyte can be sent in the opposite direction to the direction in which the strip travels, but if the line speed becomes high, the electrolyte will flow due to the viscosity of the strip 2 and the electrolyte. Since the electrolyte is carried out in the direction of travel of the strip 2, if the electrolyte is injected in the opposite direction to the direction of travel of the strip 2, the electrolyte will stagnate in the cylindrical electrolytic cell 1 and the gas generated on the electrolytic surface will not be removed, causing the electrolytic The voltage will rise. Note that 4 is a nozzle and 5 is a seal plate.

Furthermore, as shown in FIG. 8, JP-A-60-177200 discloses that the electrolytic solution is injected in the same direction to the strip 2 passing through the cylindrical electrolytic cell 1 to narrow the electrolytic solution outlet of the cylindrical electrolytic cell 1. Therefore, we proposed an electrolytic cell that aims to maintain the electrolytic solution on the electrolytic surface while passing the strip 2 at high speed, and to efficiently exhaust the gas generated on the electrolytic surface. In this case, the vibration of the strip 2 cannot be suppressed and the distance between the strip 2 and the electrode 3 cannot be shortened.

In addition, since the outlet of the cylindrical electrolytic cell 1 is narrowed, it becomes more difficult to narrow the distance between the electrode 3 and the strip 2 by the narrowed outlet, making it impossible to lower the electrolytic voltage.
6 is a header.

Japanese Patent Publication No. 61-18433 maintains static pressure on the electrolytic surface by installing a seal spray at the electrolyte outlet as shown in Figs. 9 and 10, and this static pressure prevents the vibration of the strip 2 and the strip 2 can be stably passed through the electrolytic cell, the distance between the strip 2 and the electrode 3 can be shortened to lower the electrolytic voltage, and the gas generated on the electrolytic surface can be easily discharged. However, this electrolytic cell works effectively up to a line speed of 200 mpm, but as the line speed increases further, the electrolyte is carried out along with the strip 2 due to the viscosity of the strip 2 and the electrolyte. It becomes difficult to eject the gas in the opposite direction to the traveling direction of the strip 2, and the gas generated on the electrolytic surface becomes stagnate. Furthermore, in the electrolytic cell shown in FIG. 10, the strip 2 carries out the electrolytic solution, making it difficult to maintain the electrolytic solution on some electrolytic surfaces.

As described above, in the electrolytic treatment apparatus proposed so far, as the line speed increases, it is not possible to simultaneously satisfy the requirements of stable strip passing and efficient removal of gas generated on the electrolytic surface.

<Problems to be Solved by the Invention> In order to prevent the strip from vibrating in the electrolytic cell, it is effective to generate static pressure on both electrolytic surfaces of the strip using an electrolytic solution.

One method for generating static pressure on the electrolytic surface is to pass a strip through a cylindrical electrolytic cell that has electrodes inside, and inject electrolyte from the strip inlet of the cylindrical electrolytic cell to the strip outlet of the cylindrical electrolytic cell. There is a method of applying pressure to generate static pressure on the electrolytic surface while draining the electrolytic solution to the extent that the gas generated on the electrolytic surface can be removed.

However, in the method of using a seal spray at the strip outlet of a cylindrical electrolytic cell, as the speed of the strip increases, the electrolyte is carried out due to the viscosity of the strip and electrolyte. However, there is a problem in that it is difficult to generate static pressure on the electrolytic surface.

The present invention solves the above-mentioned problems, and provides an electrolytic treatment method that enables electrolytic treatment at high current density and low voltage while passing the strip at high speed, thereby producing smooth steel sheets of stable quality with stable operation. The purpose is to provide such equipment.

Means for Solving the Problems> The present inventors have discovered that in order to maintain static pressure in a cylindrical electrolytic cell through which a strip passes at high speed, the electrolytic solution is injected from the strip inlet of the cylindrical electrolytic cell. The present invention is based on the knowledge that at the strip outlet, pressure is applied to discharge the electrolyte jetted from the strip inlet and the electrolyte carried out by the strip itself to the extent that the gas generated at the electrolytic surface is removed. It has arrived.

In order to achieve the above object, according to the present invention, an electrolytic solution is spouted in parallel to the strip surface from the strip entry side of a cylindrical electrolytic cell having electrodes disposed inside to face both sides of the passing strip, thereby electrolyzing the electrolyte. An electrolytic treatment method is provided, characterized in that the liquid level of an electrolytic solution tank communicating with the cylindrical electrolytic cell is adjusted according to the strip passing speed.

Further, according to the present invention, there is provided a cylindrical electrolytic cell having electrodes therein which are arranged opposite to both sides of the strip passing through, and a cylindrical electrolytic cell which is provided on the strip entry side of the electrolytic cell, and electrolytes from the strip entry side parallel to the strip surface. a header having a nozzle for spouting liquid; a wall surface extending to a position higher than the height of an opening on the outlet side of the electrolytic cell provided in communication with the outlet side of the electrolytic cell strip; and a liquid level adjusting means. Provided is an electrolytic treatment apparatus characterized by having a tank.

The present invention will be explained in more detail below.

1 to 3 are a partially sectional side view, a plan view, and a front view of an electrolytic treatment apparatus showing one example of the present invention.

Strip 2 of cylindrical electrolytic cell 1 with electrolytic cell 8i3 arranged inside
A header 6 for injecting electrolyte into the cylindrical electrolytic cell 1 through a nozzle 4 is provided on the inlet side of the cylindrical electrolytic cell 1 .

Further, the outlet side of the strip 2 of the cylindrical electrolytic cell 1 is connected to a night cell 7 having a wall surface higher than the height of the upper surface of the opening of the cylindrical electrolytic cell 1 by opening the outlet side opening. ing.

A suitable overflow pipe 8 is provided in the liquid tank 7 as a liquid level adjusting means. 9 is a conductor roll.

Next, the electrolytic treatment method of the present invention will be explained based on a preferred embodiment shown in FIG.

In FIG. 1, a cylindrical electrolytic cell 1 in which electrolyte is injected through a nozzle 4 from the inlet side of a strip 2 of the cylindrical electrolytic cell 1.
When the strip 2 is passed inside, the electrolyte is injected parallel to the surface of the running strip 2, and the electrolyte is injected into the strip 2.
The electrolytic treatment is carried out by electrodes placed opposite to each other on both sides of the plate.

Here, the electrolytic solution injected into the cylindrical electrolytic cell 1 communicates with a liquid tank 7 provided on the outlet side, and the liquid level of this liquid tank 7 is adjusted by adjusting the height of the overflow pipe 8. If the cylindrical electrolytic cell 1 is maintained at a predetermined height higher than the upper surface of the outlet opening, static pressure will be generated on the upper and lower electrolytic surfaces of the strip 2 within the cylindrical electrolytic cell 1, and the vibration of the strip surface 2 will be suppressed. It can be suppressed.

As the line speed increases, it becomes easier for the strip 2 to carry out the electrolyte from the electrolytic surface. The gas generated on the electrolytic surface can be removed through the liquid tank 7 while maintaining the static pressure on the electrolytic surface, and the electrolytic solution can be discharged from the overflow pipe 8 to the same level as a stone.

To adjust the liquid level in the liquid tank 7, adjust the height of the overflow pipe 8 according to the stripping speed to maintain a constant liquid level suitable for the stripping speed at that time, or adjust the liquid level to an appropriate level each time the stripping speed changes. Preferably, a liquid level meter 10 is installed in the liquid tank 7 as shown in FIG.
A liquid level signal 11 and a strip speed signal 12 are provided.
is sent to the controller 13 into which appropriate strip speed and liquid level relationship values are input in advance, and the position of the overflow pipe 8 is adjusted based on the command from the controller 13. Electrolyte supply amount control or
Self-a-control to control the amount of electrolyte discharged in step 1 and 15 7
It's okay. In addition, 16 is a priddle roll, 17 is a pulse generator, 18 is an overflow tube position adjustment signal, and 19 is an electrolyte supply! The adjustment signal 20 is an electrolyte discharge amount adjustment signal.

In addition, if an edge mask 21 is installed near the edge of the strip 2 in the cylindrical electrolyzer a1 as shown in FIG. 3, it will prevent the edges of the strip 2 from being overcoated and separate the upper and lower electrolytic surfaces of the strip 2, thereby reducing the static pressure. The cushioning effect on the strip 2 can be further enhanced.

In the apparatus of the present invention shown in FIG. 1, the relationship between the stripping speed and the amount of electrolyte flowing out on the electrolyte outlet side of the cylindrical electrolytic cell and the relationship between the stripping speed and the amount of electrolyte flowing out at the electrolyte outlet side of the cylindrical electrolytic cell, and chromic anhydride of 100 g/j2. Using an electrolyte of 0.4 g/jl of sulfuric acid and 5 g/l of sodium silicofluoride,
The relationship between the stripping speed and the electrolysis voltage when electrolysis was carried out by flowing an electrolysis current of A was as shown in FIGS. 5 and 6. The distance between the strip and the electrode was 8 mm, and a Pb electrode with an electrode length of 500 mm was used. In addition, the liquid level in the liquid tank was adjusted according to the stripping speed (ul)
.

For comparison, the cases where the apparatus shown in FIG. 7 (u,), the apparatus shown in FIG. 8 (ua), the apparatus shown in FIG. 9 (ul), and the apparatus shown in FIG. 10 (U+) are also shown. . however,
ul in Fig. 5 (IA is the strip entry side of the electrolytic cell,
u foil indicates the amount of electrolyte flowing out at the outlet side of the strip.

For u and u6, the amount of electrolyte flowing out at the electrolyte outlet is constant, but for u? , UL, as the stripping speed increases, the electrolyte is pushed back and the amount of electrolyte flowing out at the electrolyte outlet decreases.

ul. As the stripping speed increases, the amount of electrolyte flowing out at the strip outlet side increases (u106), but the amount of electrolyte flowing out at the strip inlet side decreases (ulo^), and when the stripping speed is 200 mpm or more, the amount of electrolyte flowing out at the strip exit side increases (u106), and when the stripping speed is 200 mpm or more, The electrolyte only flows halfway from the point to the outlet side of the strip (see Figure 5).

Regarding the electrolytic voltage of the electrolytic cell, the electrolytic voltage is stable in U because the vibration of the strip is suppressed even if the stripping speed increases and the gas generated on the electrolytic surface is efficiently removed.

In u7 and ul, as the stripping speed increases, the electrolytic solution accumulates on the electrolytic surface, gas remains on the electrolytic surface, and the voltage increases. ul. In this case, as the stripping speed increases, the electrolytic solution on the electrolytic surface from the electrolytic solution supply port in the center of the electrolytic cell to the strip entry side becomes insufficient, and the electrolytic voltage increases. In u6, the electrolysis voltage fluctuated due to the large vibration of the strip, and the strip came into contact with the electrode midway through, so electrolysis was stopped.

<Example> The present invention will be specifically explained below based on Examples.

(Example 1, Comparative Examples 1 and 2) Using the electrolytic cell of the present invention shown in FIG.
Plating was performed using a plating solution containing 0 g/u, sulfuric acid 0.4 g/It, and sodium fluorosilicate 5 g/2, and the electrolytic current was increased as the stripping speed was increased. The plating results are shown in Table 1.

The electrolytic voltage increases as the electrolytic current increases, but since the strip vibration is suppressed, the stripping speed remains at 500.
Chromium plating was possible even at mpm, and a uniform ROM layer with a good appearance was obtained.

In Comparative Example 1 using the electrolytic cell shown in Fig. 7, as shown in Table 1, due to an increase in stripping speed and an increase in electrolysis voltage, when the stripping speed exceeds 100 mpm, the electrolysis voltage exceeds the rectifier capacity, and the electrolysis stops. It's now possible. In addition, in Comparative Example 2 using the electrolytic cell shown in Figure 10, as shown in Table 1, as the stripping speed increases, the flow of the electrolytic solution in the electrolytic cell becomes uneven, and brown stains occur. However, when the stripping speed exceeded 150 mpm, the electrolytic voltage exceeded the rectifier capacity, making electrolysis impossible.

<Effects of the Invention> Since the present invention is configured as detailed above, it is possible to perform electrolytic treatment at high current density and low voltage while passing the strip at high speed, making it possible to improve the efficiency of the electrolytic process. Even when the strip passes through the process at high speed, it is now possible to achieve stable operations and plated steel sheets of stable quality.

Furthermore, by combining members with a simple structure, the device of the present invention can discharge electrolyte while maintaining an appropriate static pressure in the cylindrical electrolytic cell even when the strip runs at high speed. The pressure on the electrolyte outlet side of the cylindrical electrolytic cell can be easily adjusted, suppressing the vibration of the strip in the electrolytic cell from low to high stripping speeds, and removing gas generated on the electrolytic surface. This effect is achieved.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view showing an example of the electrolytic treatment apparatus of the present invention. FIG. 2 is a plan view of the same. FIG. 3 is a front view of the same. FIG. 4 is a partially sectional side view showing another example of the device of the present invention. FIG. 5 is a graph showing the relationship between strip speed and electrolyte outflow amount. FIG. 6 is a graph showing the relationship between strip speed and electrolysis voltage. FIG. 7 is a diagram showing a first conventional example. FIG. 8 is a diagram showing a second conventional example. FIG. 9 is a diagram showing a third conventional example. FIG. 10 is a diagram showing a fourth conventional example. Explanation of symbols 1... Cylindrical electrolytic cell, 2... Strip, 3... Electrode, 4... Nozzle, 5... Seal plate, 6... Header 7... Liquid tank, 8 ...Overflow pipe, 9...Conductor roll, 10...Liquid level meter, 11...Liquid level signal, 12...Strip speed signal, 13...Controller, 14... Pump, 5...Valve, 13...Pridle roll, 17...Pulse generator 18...Overflow pipe position adjustment signal, 19...
Electrolyte supply amount adjustment signal, 20... Electrolyte discharge amount adjustment signal, 21... Edge mask

Claims (2)

[Claims] (1) In an electrolytic treatment method in which electrolyte is ejected parallel to the strip surface from the strip entry side of a cylindrical electrolytic cell that has electrodes placed inside to face both sides of the strip passing through, the strip passing speed is An electrolytic treatment method characterized by adjusting the liquid level of an electrolytic solution tank communicating with the cylindrical electrolytic cell accordingly. (2) A cylindrical electrolytic cell with electrodes placed inside to face both sides of the passing strip, and a nozzle provided on the strip entry side of the electrolytic cell that spouts electrolyte parallel to the strip surface from the strip entry side. An electrolytic processing apparatus characterized by having a header having a header and a wall surface extending to a position higher than the height of an upper surface of an opening on the electrolytic cell outlet side provided in communication with the electrolytic cell strip outlet side.