JPS5817270B2 - Electrode device for electrolysis - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present inventors have previously disclosed patents Nos. 212080 and 229.
No. 381, No. 294943, and No. 726754 provide an electrodeposition method in which the shape of an electrodeposited material can be adjusted to, for example, a smooth plate shape by molten salt electrolysis.

The present invention relates to improvement of an electrode device for electrolysis, that is, a cathode device, which is suitable for use when obtaining metals or alloys by such molten salt electrolysis.

FIG. 1 is a schematic diagram of a molten salt electrodeposition apparatus, in which 1 is a bathtub containing a molten salt electrolytic bath 2, and an anode 3 is placed inside the bathtub 1.
and a cathode 4 are respectively arranged at predetermined positions.

In this case, the cathode 4 for depositing the vastly regulated electrolytic product is configured to be able to rotate (or vibrate) in the bath,
In particular, in order to make the cathode itself lightweight and to avoid overheating due to the difference in thermal expansion coefficient between the cathode 4 in contact with the bath 2 and the rotating shaft 5 that rotates it, it is constructed of a hollow cylindrical body, for example, a cylindrical body. .

FIG. 2 shows a specific example of a conventional rotating cathode 4, which includes an electrode main body 6 made of a hollow metal cylinder, an insulating cylindrical holder 7, and a motor (not shown). A conductive ring 9 is fitted onto the rotating shaft 5 inserted into the electrode main body 6, and the fitting part of the rotating shaft 5 with the conductive ring 9 is a tapered circle. A conductive ring 9 is formed by a nut 10 having a tapered portion 5a and screwed into the screw of the rotating shaft 5.
is pushed up along the tapered portion 5a, and due to the frictional engagement between the inner surface of the through hole 9a of the small conductive ring 9 and the aperture portion 5a, the rotating shaft 5 and the electrode body 6 are rotationally integrated and made electrically conductive. configured to do so.

The holder 7 is provided to protect the rotating shaft 5 from being wetted by the electrolytic bath 2 when the electrode main body 6 is placed in the electrolytic bath 2 and from forming deposits thereon.

The holder 7 and the cathode section 6 are connected through an intermediate ring 11 and a seal section 13 made of asbestos 12 therebetween.

Further, caps 14 and 15 are disposed at the upper end of the holder 7 and the lower side of the electrode main body 6, respectively, to close the caps 14 and 15, and these are similarly joined together via the asbestos 12.

By the way, in the conventional cathode device 8, a ceramic holder was used as the holder 7, and asbestos 12 was used as the sealing member.
This ceramic holder 7 lacked mechanical strength and was easily damaged by, for example, a crust (coagulated film) formed on the surface of the electrolytic bath 2.

- Although the mechanical strength of the holder 7 increases if it is made of metal, electrical insulation between the holder and the cathode body 6 or the rotating shaft 5 is difficult.

That is, in order to keep the electrodeposition conditions constant, the cathode body 6
must be placed in a constant position below the bath surface, so naturally the connection between the holder 7 and the catholyte body 6 is also immersed in the bath.

Therefore, if this connecting part is in the bath for a long time, the electrolytic bath 2 will seep between the asbestos 12 and the holder 7, and current will flow from the electrode part 6 to the holder 7 or the intermediate ring 11, etc. 11 or electrodeposition also occurs on the holder 7, which changes the deposition area and changes the electrodeposition conditions, etc.
It is easy to cause inconvenience.

In view of the above-mentioned points, the present invention provides a cathode device with excellent durability, in which the holder is made of metal to improve its mechanical strength, and the seal portion is improved to ensure electrical insulation to the holder. It is.

Hereinafter, the present invention will be explained in detail using FIG.

Note that parts corresponding to those in FIG. 2 are designated by the same reference numerals and redundant explanation will be omitted.

In the present invention, as shown in FIG. 3, a rotating shaft 5 is inserted into a cathode main body 6 made of a hollow metal cylinder, and a conductive ring 9 is attached to a tapered portion 5a at the tip of the rotating shaft 5. Attachment: The cathode main body 6 and the rotating shaft 5 are rotationally integrated via the conductive ring 9 (the above is the same as in the conventional example).

A metal (for example, stainless steel) cylindrical holder 16 that protects the rotating shaft 5 is arranged on the cathode main body 6 via an intermediate ring 11, and between the intermediate ring 11, the holder 16, and the cathode main body 6. A seal portion 17 is inserted into each.

A similar sealing portion 17 is also inserted between the upper end of the holder 16 and the cap 14 that closes it.

This sealing part 17 is made of a heat-resistant and insulating cushion material 18 made of asbestos, for example, and a so-called impermeable insulating material that is heat-resistant, does not allow the electrolytic bath 2 to penetrate, and has excellent electrical conductivity, such as mica. It is constituted by a laminate with a body 19.

In this case, the intermediate ring 11 has a flange 11a that abuts against the outer peripheral surface of the seal portion 17.

Here, the laminated arrangement relationship between the cushion material 18 and the impermeable insulator 19 is such that the impermeable insulator 19 is arranged on the side that contacts the holder 16 or the cathode body 6, and the intermediate ring 11
Alternatively, the cushioning material 18 may be placed on the side that contacts the cap 14.

Note that the seal portion 17 of the present invention may be used between the lower end of the cathode body 6 and the cap 15, but the seal here may be composed only of the cushioning material 18 made of asbestos.

According to the cathode device having such a configuration, the mechanical strength of the boulder 16 is increased by making it metal, and the electrolytic bath 2
The sealing portion 17 made of a laminate of mica 19 and asbestos 18 provides a reliable airtight seal between the holder 16 and the rotating shaft 5 or between the holder 16 and the cathode Electrical insulation between the main bodies 6 is ensured.

Also, in the seal part 17? For example, if mica 19 is
16 or placed on the cathode main body 6 side, example O is asbestos 18
When the intermediate ring 11 or cap 14 side is placed, electrical insulation becomes even more reliable.

The reason for this is that even if the electrolytic bath 2 were to penetrate into the asbestos 18, the electrolytic bath 2 would not penetrate into the mica 19, so that the mica 19 would maintain insulation from the holder 16.

Conversely, when mica 19 is placed on the intermediate ring 11 or cap 14 side and asbestos 18 is placed on the holder 16 side,
If the electrolytic bath 2 is left in the electrolytic bath 2 for a long time, the electrolytic bath 2 will soak into the asbestos 18, and there is a risk that current will flow from the rotating shaft 5 to the holder 16 or the intermediate ring 11 through the asbestos 18.

Furthermore, in this case (as in the conventional example), the flow of the bath due to the rotation of the electrodes directly hits the nonwoven fabric such as asbestos 18, causing the disadvantage that it is peeled off and dispersed in the bath.

Therefore, it is important to consider the order in which the laminate is arranged.

According to the present invention described above, a highly durable and highly reliable electrode device for electrolysis can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a molten salt electroplating device used to explain the present invention, and FIG. 2 is a sectional view showing an example of a conventional cathode device.
FIG. 3 is a sectional view showing an example of a cathode device according to the present invention. 1 is a bathtub, 2 is a molten salt electrolytic bath, 3 is an anode, 4 is a cathode, 5
1 is a rotating shaft, 6 is a cathode main body, 11 is an intermediate ring, 16 is a metal holder, 17 is a sealing portion, 18 is a cushioning material, and 19 is an impermeable insulator.

Claims (1)

[Claims] 1. In an electrode device for obtaining metals or alloys by molten salt electrolysis, the electrode part body and the metal part holder are combined with an intermediate ring having a flange, and the intermediate ring is equipped with an impermeable insulator and a cushion. An electrode device for electrolysis, wherein a laminate of materials is housed with its outer peripheral surface abutting against the flange of the intermediate ring, and at least the cushion material does not come into direct contact with the electrolytic bath.