JPS6014758Y2 - Etching solution regeneration device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a regeneration device using electrolytic oxidation of an etching solution.

In order to plate a syncytial resin such as ABS resin, etching is required as a pretreatment.

A mixed acid of chromic acid and sulfuric acid is mainly used for this etching, and it is thought that etching occurs when the resin is oxidized by the following reaction of chromic acid, namely Cr"+3e-+Cr". It is being

Therefore, when etching is performed in this way, hexavalent chromium in the etching solution is reduced to trivalent chromium, and
As the concentration of valent chromium increases, the etching power of the etching solution becomes weaker.

Therefore, aged etching solutions require renewal or regeneration.

As one of the methods for regenerating this etching solution, there has conventionally been an electrolytic oxidation method.

In this method, an insoluble electrode is placed in an aged etching solution, direct current electrolysis is carried out, and an electrochemical reaction near the anode oxidizes trivalent chromium to hexavalent chromium, as is known in the art.

In this case, the amount of trivalent chromium oxidized to hexavalent chromium by direct current electrolysis is based on Fraday's law, and the amount of Ig trivalent chromium oxidized to hexavalent chromium is proportional to S゛ for the current passed through the electrode. In order to do this, it is necessary to apply DC electricity of approximately 2.0 amperes for one hour.

In this electrolytic oxidation regeneration method, as shown in FIG. This is done by energizing.

Etching solution 11 to be electrolytically oxidized is pumped up from etching tank 9 by pump 6 and introduced into electrolytic tank 1 through piping 7, where it is electrolytically oxidized and then sequentially overflowed from electrolytic tank 1 and discharged, and then passed through piping 8. After that, it is returned to the etching tank 9 again.

Note that the cathode 3 is surrounded by a diaphragm 4 and held in the cathode chamber liquid 12 to prevent unnecessary materials from being electrodeposited.

The wiring 5 to each electrode is connected in parallel to a power source 10, as shown in FIG.

In this way, in conventional equipment, a large number of anodes and cathodes are installed in one electrolytic bath for anodic oxidation, and the current capacity of the DC power supply used to regenerate the etching solution depends on the amount of oxidized trivalent chromium. It needed a size proportional to.

In the normal etching process of synthetic resin plating, an electrolytic oxidation regeneration device with a power source with a DC current capacity of several hundred amperes to several thousand amperes is installed. There was a problem of high cost.

The present invention is intended to solve the above-mentioned conventional problems, and aims to provide a regeneration device that can reduce the current capacity of the DC power supply used in electrolytic oxidation regeneration of etching solution, and reduce equipment costs. This is what I did.

Specifically, the present invention creates different levels of various liquids so that the etching liquid to be regenerated passes through multiple electrolytic cells continuously, and overflows sequentially from the tank with a high liquid level to the tank with a low liquid level. The etching solution is installed so that it can flow, and each type is electrically insulated from each other, and the anode and cathode attached to each type are wired in series with a DC power supply, and electricity is applied to electrolytically oxidize the etching solution. It is characterized by

According to the present invention, since each electrode is connected in series to the power source, the current capacity of the DC power source can be reduced from one to several tenths of that of conventional devices.

At the same time, it is also possible to reduce the capacity of the DC wiring.

Note that the present invention is applicable not only to the regeneration of etching liquid, but also to equipment for electrolytic oxidation treatment of cyanide wastewater, electrolytic production of caustic soda, etc.

The present invention will be explained below with reference to the drawings.

An embodiment of the present invention will be described with reference to FIGS. 2 and 3.

In the figure, reference numerals 1 and 1' denote electrolytic cells containing an etching solution 11 to be regenerated, which is made of a steel plate lined with lead.

Both electrolytic cells 1 and 1' have an overflow, and the overflow outlet of the first electrolytic cell 1 is installed so that the liquid flows into the next electrolytic cell 1'.

Installation is carried out by placing the electrolytic cells 1, 1' and the mounts 13.13' on mounts 13.13' of different heights.
13', an insulator 14 is placed between them so that they are electrically insulated from each other.

The electrodes provided in the electrolytic cells 1, 1' support an anode 2 and a cathode 3 facing each other, as in the conventional device, and the cathode 3 is supported by a diaphragm 4.
The diaphragm 4 is filled with dilute sulfuric acid as the cathode chamber liquid 12.

The wiring 5 connects the negative electrode of the DC power supply 10 and the cathode of the electrolytic cell 1, then connects the anode of the electrolytic cell 1 and the cathode of the electrolytic cell 1', and then connects the anode of the electrolytic cell 1' and the DC power source 1o. Connect to the positive terminal of

By wiring in this way, two electrolytic cells 1 and 1'
The cathode and anode of are connected in series to the DC power supply, resulting in the following advantages.

Note that 15 in the figure indicates a hood for exhausting mist generated during electrolysis.

In the above embodiment, there are two electrolytic cells, but as shown in the flow sheet of FIG. Of course.

- Also, for electrically insulating the electrolytic cells from each other, the insulator 14 can be omitted by making the electrolytic cells themselves from a non-conductor or by lining them with a non-conductor.

Next, the operation of the device according to the present invention will be explained based on the flow sheet shown in FIG.

The etching process is performed in an etching tank 9.

The etching solution in the etching tank 9 is pumped up by the pump 6 and sent to the electrolytic tank 1 through the piping 7.

Furthermore, the etching solution in electrolytic cell 1 is sequentially sent to electrolytic cell 1' and electrolytic cell 1'' by overflow.

During this time, the etching solution is electrolytically oxidized in each electrolytic cell.
Trivalent chromium in the liquid becomes hexavalent chromium.

The etching solution thus regenerated is discharged from the overflow of the last electrolytic cell 1'' and returns to the etching bath 9 through the pipe 8.

In the above, the current used for regenerating the etching solution is supplied from the positive terminal of the DC power supply 10 through the wiring 5 to the electrolytic cell 1''.
It flows to the anode of the electrolytic cell 1'', further passes through the etching solution and the cathode chamber liquid 12, and flows to the cathode of the electrolytic cell 1'', then passes through the wiring 5a,
It flows to the anode of electrolytic cell 1'.

Thereafter, electricity similarly flows through the wiring 5b to the cathode of the electrolytic cell 1, and then flows into the negative electrode of the DC power supply 10.

Note that electrical paths other than those described above do not exist because the electrolytic cells are insulated from each other.

By configuring as described above, the present invention has the following advantages.

The first advantage is that the equipment cost of the DC power supply can be reduced.

For example, in the embodiment shown in Fig. 2, an IOV, 100OA rectifier was used, whereas a conventional device used a 5V, 2000A rectifier.
A rectifier is required.

As is well known, DC power supplies such as silicon rectifiers have
Increasing the voltage capacity has little effect on equipment costs, but increasing the current capacity increases equipment costs at a constant rate per ampere.

Now, assuming that the equipment cost increases by about 1,000 yen per ampere, we calculate that in the above example, the electrolytic cell is divided into two parts, electrically connected in two stages, and the required current is reduced to one-half. The equipment cost can be reduced by 1,000,000 yen.

In the example shown in FIG. 4, the installation cost of the DC power supply can be reduced to about one-third.

Next, the second advantage is that since the wiring cost is proportional to the current, the present invention requires only a low current as described above.
DC wiring equipment costs can be reduced.

As explained above, the present invention has many advantages, such as being easy to manufacture and having low equipment costs, as it only requires adding an electrolytic cell and changing the wiring, and can be used in various fields as it can operate with low current. has.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional device, Fig. 2 is a partially cutaway side view showing an embodiment of the present invention, Fig. 3 is a plan view of Fig. 2, and Fig. 4 is an explanatory diagram of a conventional device.
The figure is a flow sheet for explaining the present invention. In the figure, 1. 1', 1"-... Electrolytic cell, 2.
...Anode, 3...Cathode, 4...
Diaphragm, 5.5a, 5b...Wiring, 10...
...DC power supply.

Claims (1)

[Scope of utility model registration request] In order for the etching solution to pass through multiple electrolytic cells continuously,
By creating height differences in the various liquid levels, and by overflow,
The etching solution was installed so that it flowed sequentially from the tank with a high liquid level to the tank with a low liquid level, and each type was electrically insulated from each other.
An etching solution regeneration device characterized in that an anode and a cathode attached to various parts are wired in series to a DC power source, and the etching solution is electrolyzed by energizing the wires.