JPS6333971Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an anode for high current density electrolysis in chloride-based electrolysis, and more particularly to a high current density electrolytic anode that combines the advantages of a soluble anode and an insoluble anode.

Chloride-based electrolytes, e.g.
Zn plating solutions or ingots of chloride-Zn based alloy component metals are commonly used. This anode ingot is cast in a shape that matches the shape of the cathode in the electrolytic cell and maintains a constant distance between the electrodes. For example, in a horizontal plating tank, the ingot surface facing the strip serving as the cathode is horizontal, and in a radial plating tank, the ingot surface is arcuate.

For example, when plating a strip using such an anodic ingot, the anode surface facing the strip is mainly melted, so that as the strip width changes, the anode becomes uneven and becomes uniform in the width direction. It is difficult to obtain a plated layer with a suitable thickness and composition. In addition, because the anode ingot does not dissolve uniformly due to the difference in anode current density between the edges and the center, the anode must be removed from the electrolytic bath leaving about 1/3 to 1/2 of the anode and replaced with a new anode. However, it is economically disadvantageous.

It is also possible to use an insoluble anode, but this is not possible because there is no material that can withstand anodic electrolysis using an electrolyte mainly composed of chloride for a long period of time.

An anode for electrolysis in which metal particles are housed in an insoluble anode cage has also been proposed, but in the case of high current density electrolysis, it is difficult to uniformly supply a large current.

In order to improve these problems, this invention
As a result of detailed studies, we have provided an electrolytic anode that combines the advantages of a soluble anode and an insoluble anode, and is particularly suitable for high-current density electrolysis with good productivity.

That is, the present invention uses metal grains as an anode and an anode case that houses the anode for electrolysis.The side of the anode case facing the cathode is an insulator with many holes, and the metal grains are used as the cathode. Mainly chloride, characterized by having a Ti plate on the side (rear side) facing through, and providing a current-carrying projection with excellent corrosion resistance such as Ti, Nb, Ta, stainless steel, or Ni alloy on the Ti plate. The present invention provides an anode for high current density electrolysis of electrolytes.

A detailed explanation will be given below with reference to the drawings.

Figure 1 is a perspective view of the electrolytic anode case of the present invention;
FIG. 2 is a side view. The side 2 of the anode case 1 facing the cathode is made of an insulating material such as plastic, and has a sufficient number of holes 3 to contact the metal grains 4 in the electrolytic case and to allow liquid to enter and exit without stagnation. It is being Back side 5 and side 6 of case
is composed of a Ti plate, which is in contact with metal grains inside the case. The outside of parts 5 and 6 that make up this case are coated with an insulating material. A large current is applied to this anode case from the power supply terminal 7 for high current electrolysis, but simply contacting the metal grains and the Ti plate will cause a difference in contact resistance, so the large current is applied to the cathode facing the cathode. Unable to supply power evenly to the surface being used.

Therefore, by installing protrusions 8 in electrical contact with the Ti plate at appropriate intervals within the case, we succeeded in significantly increasing the contact area with the metal particles and obtaining a uniform current distribution.

The reason why the material on the side of the anode case facing the cathode is an insulator is because the electrolyte containing chloride is extremely corrosive, so if a metal material is used, it will This is for anodic dissolution.
Therefore, it is desirable that the length of the current-carrying protrusion attached to the Ti plate be approximately 2/3 of the case thickness, and that it be buried within the metal grains. The shape of the protrusions and the mounting interval are not particularly limited as long as they do not interfere with the movement of the metal particles.

The material of the protrusion is not particularly limited, as long as it can conduct electricity, even metals with excellent corrosion resistance such as Ti, Nb, Ta, stainless steel, and Zi alloys, or magnetic materials such as ferrite.

In addition, instead of the Ti plates 5 and 6, corrosion-resistant materials such as Zb, Ta, stainless steel, and Ni alloys can be used depending on the composition of the electrolytic solution and the electrolytic conditions. Carbon plates can also be used.

3 and 4 are side views of the modified anode case of the present invention.

In FIG. 3, the Ti plate 5 is tilted to make the metal particle supply port larger and narrower toward the back. This reduces the amount of metal grains charged into the anode case and improves structural strength. Some of the charged metal grains do not remain, allowing for smooth refreshment. Since there are fewer metal grains in contact with the Ti plate in areas far from the power supply section, there are advantages such as less current flow resistance between the metal grains and better uniform current distribution.

Further, FIG. 4a shows an arc-shaped anode case, which is useful for radial cells. FIG. 4b shows an example in which it is more effective to spread out when considering the accumulation of anode slime generated during long-term electrolysis.

Example Fig. 4 shows an arc-shaped electrolytic anode applied to the radial cell shown in Fig. 5, and the current density due to chloride liquid
Zn-Ni alloy electroplating was performed. The electrolysis conditions are as follows.

(1) Zn-Ni alloy plating liquid Zinc chloride 250g / Nickel chloride 50g / Ammonium chloride 350g / PH 4.0 Melting temperature 50℃ Current density 50-200A/dm ² Metal grains: Zinc grains, Nickel grains For long-term line operation There were no abnormalities in the anode case for electrolysis of the present invention, and the metal particles could be smoothly anodically melted.

Furthermore, the deposited amount and Ni content of the obtained Zn--Ni alloy plating layer were uniform in the width direction.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an electrolytic anode case provided with an energizing protrusion of the present invention, Fig. 2 is a side view thereof, Figs. 3 and 4a and 4b are side views of a modified anode case, and Fig. 5 The figure is a side view of a radial cell to which the anode case of the present invention is applied. Code, 1... Anode case for electrolysis, 2... Front of the anode case, 3... Hole drilled in the front, 4... Metal particles, 5... Back of the anode case, 6... Side of the anode case, 7... Power supply Terminal, 8... Protrusion for current-carrying, 9...
...Conductor roll, 10...Counterflow nozzle, 11...Anode slime.

Claims (1)

[Scope of utility model registration request] In an electrolytic anode consisting of a metal grain as an anode and an anode case that houses the anode, the side of the anode case facing the cathode is an insulator with many holes, and the side facing the cathode through the metal grains. An anode for high current density electrolysis of an electrolyte containing chloride as a main component, characterized in that the Ti plate is provided with conductive protrusions for current flow having excellent corrosion resistance.