JPS62127500A - Electrolyzing method and apparatus - Google Patents

Abstract

PURPOSE:To attain stable conditions under which electrodes are not dissolved, by placing graphite electrodes and an auxiliary electrode in the same treating vessel and supplying part of electric current in each of forward and backward periods to the auxiliary electrode so that the electrode always acts as anode. CONSTITUTION:An apparatus for continuously treating a metallic web 1 is composed of an electrolytic cell 4 provided with graphite electrodes 7, 8 and an auxiliary electrode 30 and of a power supply unit provided with a power source 14 for supplying AC to the electrodes 7, 8, 30. Part of AC in each of forward and backward periods is supplied to the auxiliary electrode 30 so that the electrode 30 always acts as anode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electrode treatment using alternating waveform current, and in particular to a method and apparatus for continuous electrolytic treatment of metal webs.

[Conventional technology]

Regarding the power supply method when performing electrode treatment using conventional alternating waveform current, an auxiliary anode electrode (hereinafter referred to as auxiliary electrode) is installed outside the graphite electrode, and a part of the current is diverted to the auxiliary electrode. The insoluble condition of the electrode has been dealt with by always maintaining the current conditions at the electrode such that the anode current and the cathode current are established (for example, Japanese Patent Application Laid-Open No. 59-21550
(See Japanese Patent Application Laid-Open No. 60-67699). In this case, as an electrode processing device, the auxiliary electrode is connected to either the forward side or the reverse side, or to the forward side and the reverse side, respectively.
It was set up for ke.

[Problem that the invention seeks to solve]

Therefore, a comb-wave-shaped current flows through the auxiliary electrode of a conventional electrolytic treatment device, so if the auxiliary electrode is installed together with the graphite electrode in the main reaction tank, it will be in a stable state when the auxiliary electrode is flowing. In a rest state where no current flows, a small amount of current flows through the auxiliary electrode, which causes the electrode to melt when used for a long time. Therefore, in order to prevent this, the auxiliary electrode is generally installed in an auxiliary tank that is separate from the main reaction tank, or if it must be installed in the same tank, it is necessary to set the auxiliary electrode to an auxiliary tank that is designed to prevent current flow between the bridges. It was necessary to use a high insulator, which was a major problem with the equipment.

The present invention provides electrolytic treatment using alternating waveform current,
To provide an electrolytic treatment method and device that can obtain stable indissolution conditions without providing an auxiliary tank separate from a main reaction tank or using a highly accurate insulator when installing an auxiliary electrode in the reaction tank. It is in.

[Means for solving problems]

The present invention provides, as a first invention, a continuous electrolytic treatment method for a metal web by liquid power supply using alternating waveform current for a graphite electrode and an auxiliary anode electrode, in which the graphite electrode and the auxiliary anode are provided in the same treatment tank. , shunting a portion of each current during the forward and reverse cycles to the auxiliary anode electrode;
An electrolytic treatment method characterized in that one auxiliary anode always acts as an anode, and a second invention provides an electrolytic cell having a graphite electrode and one auxiliary anode, and the graphite electrode and the auxiliary anode. In a continuous electrolytic treatment apparatus for a metal web, the graphite electrode and the auxiliary anode electrode are provided in the same treatment tank, and the auxiliary anode electrode is provided in the same treatment tank. This electrolytic processing apparatus is characterized in that the contacts on both sides of a power source are connected to each other by circuits each having a rectifying element and a variable resistor.

The present invention will be explained by way of an example with reference to FIG.

The metal web (1) is guided into the electrolytic cell (4) by guide rolls (16), horizontally conveyed by support rolls (3), and transferred from the guide rolls (26) to the outside of the cell.

Inside the tank, there is a graphite electrode (7) corresponding to the metal web (1).

(8) An auxiliary electrode (30) is provided, and the auxiliary electrode uses platinum <pt> or lead (Pb) as an insoluble 7-node electrode. Note that the positional relationship between the graphite electrodes 1 (7), (8) and the auxiliary electrode (30) can be arbitrarily selected. Electrolyte (28
) is sent from the circulation tank (9) to the supply ports (19), (29) of the electrolytic solution (28) by the pump (10), filling the electrolytic cell (4) and passing through the discharge port (13) to the circulation tank (9).
Return to ). Although not shown in the drawings, the electrolytic solution (28) is precisely controlled by a heat exchanger and a filter installed in a part of the circulation system, and impurities are separated and removed by the filter.

On the other hand, as for the electrical system, the electric current a (14) connects one contact to an auxiliary type
(30), and the other contact is connected to the same auxiliary electrode (30) via a graphite electrode (8), a variable resistor (34), and a rectifying element (32) such as a silice or a diode.

[Effect]

A power source (
14) It can flow more easily. When the forward current value of the alternating current is I (n), the forward cycle current 1 (n) flows through the graphite electrode (7) and the auxiliary electrode (30), and further flows into the electrolyte (
Electricity is supplied to the web (11) through the electrolyte (28), and further flows to the electrode (8) via the electrolyte and returns to the power source (14). If the shunt ratio flowing to the auxiliary electrode at this time is α<0<α<1, graphite T! , (1-α)I(n) for the scratch (7), α[(n) for the auxiliary electrode (30), and I for the graphite electrode (8).
(n) flows.

On the other hand, during the reverse cycle, when the current is I (r), the reverse current flows through the graphite electrode (8) and the auxiliary electrode (30), and further flows through the electrolyte to the web (1), and passes through the electrolyte again to form the graphite electrode. It flows to the electrode (7) and returns to the power source (14). If the division ratio flowing to the auxiliary electrode (30) at this time is β<0<β<1, then the graphite electrode (8) has (1-βH(r)) and the auxiliary electrode (30) has βT(r). , the graphite electrode (7) has I
(r) flows. At this time, variable resistors (33), (34
) by appropriately adjusting (1-αH(n) <I
(r), (1-β)I(r) <1 (n) is obtained. This condition is such that the graphite electrode does not dissolve, and as shown in Figure 2, the auxiliary electrode (30)
is always maintained at the anode, there is no pause time or current backflow, and stable indissolution conditions are established. For this reason, graphite electrodes (7), (8) and auxiliary electrodes (30
) are both insoluble and a stable device can be obtained.

In the present invention, as the electrolytic solution (28), for example, hydrochloric acid, nitric acid, sulfuric acid, etc. are used. One embodiment of the present invention has been described above, but the present invention provides two main reaction electrodes in the same tank in electrolytic treatment using an alternating waveform power source, and a part of the current is supplied both during forward cycle and reverse cycle. The purpose is to realize an insoluble electrode by shunting the current to the auxiliary electrode and keeping the current flowing through the auxiliary electrode. Therefore, it goes without saying that the shape of the tank, the number of electrode divisions, and the order of electrode arrangement.

It is not affected by the type of electrolyte or power waveform.

〔Example〕

Example 1 Continuous electrolytic roughening treatment of an aluminum plate as an offset printing plate support was carried out in a 1% aqueous nitric acid solution at a temperature of 35 DEG C. using a symmetrical alternating waveform current with the electrode arrangement shown in FIG. A graphite electrode was used as the electrode, and platinum was used as the insoluble auxiliary anode electrode.

Forward current 1 (n) = Reverse current 1 (r) = 30OA
After continuous electrolytic treatment for 20 hours at a processing speed of 1 m/min, the surfaces of the graphite electrode and auxiliary electrode were visually observed to check for wear and disintegration. In addition, as a method of dividing the current 1 (n) bow (r) to the graphite electrode and the insoluble auxiliary anode electrode, by changing the variable resistors (33) and (34) α
.

The β value was varied. Also, the frequency is 30 to 90
Regardless of this, results showing the relationship between Ia and Ic of the graphite electrode and the state of wear of the electrode as shown in Table 1 were obtained.

Table 1 Symbol explanation ○: No change and no wear.

△: Slight wear is observed.

Also, under the above conditions N13. Regarding N11L4, it was possible to obtain an excellent roughened surface as an offset printing plate support.

Example 2 An experiment was conducted in a 1% aqueous solution of hydrochloric acid at a temperature of 35° C. under the same conditions as in Example 1, and the same results as in Table 1 were obtained regarding the stability of the electrode.

Example 3 Continuous anodization of an aluminum plate as an offset printing plate support was carried out in a 20% aqueous sulfuric acid solution at a temperature of 30 DEG C. using a symmetrical alternating waveform current with the electrode arrangement shown in FIG. A graphite electrode was used as the electrode, and lead was used as an insoluble auxiliary anode electrode. Forward current 1(n) = Reverse current I(r
) = 508 at a processing speed of 1 m/min for 20 hours, the surfaces of the graphite bridge and auxiliary electrode were visually observed to check for wear and tear. Further, as a method of dividing the flow of electrodes 1(n) and I(r) to the graphite electrode and the insoluble auxiliary 7-node electrode, the α and β values were variously changed by changing the variable resistors (33) and (34). Also, the frequency was varied from 30 to 9011z, but regardless of this, the second
Results showing the relationship between Ia and Ic of the graphite electrode and the state of wear of the electrode were obtained as shown in the table.

Table 2 Symbol explanation ○: No change and no wear.

△: Slight wear is observed.

According to the present invention, consumption of electrodes can be eliminated as described above.

The present invention is not limited to the embodiments and can be widely applied.

〔Effect of the invention〕

According to the present invention, in the method and apparatus for continuous electrolytic treatment of metal web by liquid power supply using alternating waveform current, an auxiliary tank is provided separately from the main reaction tank, and a high-precision insulator is used between the electrodes. It has become possible to obtain stable non-dissolving conditions, and one auxiliary electrode can serve as the two conventional auxiliary electrodes, making the equipment extremely simple and reducing equipment costs.

Further, since consumption of the electrodes can be eliminated, efficient continuous electrode processing is possible, the process is stabilized, and in addition to the above, maintenance and inspection work is omitted, resulting in cost reduction.

In addition, excellent electrolytically treated surface quality could be obtained by preventing an increase in impurities in the electrolyte due to electrode dissolution.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an electrolytic treatment apparatus according to an embodiment of the present invention, and FIG. 2 is a comparative diagram showing the relationship between the current ratio between the power source and each electrode during the electrolytic treatment of the present invention. ■...Metal web, 3...Support roll, 4
... Electrolytic cell, 7,8... Graphite electrode, 9...
・Circulation tank, 10...Pump, 13...Return port, 14...Power source, 16, 26...Guide roll, 19.29...Liquid supply port, 30...Auxiliary anode electrode ( auxiliary electrode), 28...electrolyte,
22.32... Rectifying element, 33, 34... Variable resistor. Figure 1

Claims (2)

[Claims] (1) In a method for continuous electrolytic treatment of a metal web by liquid power supply using alternating waveform currents for a graphite electrode and an auxiliary anode electrode, the graphite electrode and the auxiliary anode electrode are provided in the same treatment tank, and the graphite electrode and the auxiliary anode electrode are provided in the same treatment tank, and during forward and reverse cycles. An electrode processing method characterized in that a part of each current is shunted to the auxiliary anode electrode so that the auxiliary anode electrode always functions as an anode. (2) A continuous electrode treatment device for a metal web comprising an electrode bath having a graphite electrode and an auxiliary anode electrode, and a power supply equipment having a power supply that supplies an alternating waveform current to the graphite electrode and the auxiliary anode electrode. An electrode processing apparatus characterized in that an electrode and an auxiliary anode electrode are provided in the same processing tank, and the auxiliary anode electrode is connected to contacts on both sides of the power source through circuits each having a rectifying element and a variable resistance.