JP3145194B2 - Zinc electrolytic smelting method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the operation of high current density in the electrowinning of zinc kneading, and more particularly, to the upper limit of conventional high current density zinc electrolysis while controlling the temperature of a copper conductor. More than 500 A / m ² , for example, 550 A / m ² or more, or even 60
The present invention relates to a method and apparatus for operating at a high current density of 0 A / m ² or more.

[0002]

2. Description of the Related Art In recent years, in the domestic zinc electrowinning process, a method of performing high current density electrolysis during the night by using a large amount of nighttime electric power at a low unit price has been adopted. However, even in this case, the generally used current density is at most about 500 A / m ² .
Therefore, it has been desired to further increase the current density and further increase the nighttime operation rate from the viewpoint of further emphasis on nighttime power use.

However, in the current zinc electrolysis method, 50
When the operation is performed at a high current density of 0 A / m ² or more, the temperature of the contact portion between the electrode plate and the copper conductor rapidly increases, so that an oxide film is easily formed on these surfaces, and accordingly, the electrode plate or the copper There has been a problem that the conductor itself is significantly worn. In addition, since the electrolytic solution in the electrolytic cell is a sulfuric acid acidic solution, water vapor is generated as the temperature of the electrolytic solution is increased, and scale such as gypsum is generated on the electrode plate. There is also a problem that a large current flows through the electrode plate of the portion to generate a spark.

[0004]

As described above, in the conventional high current density operation, the contact resistance rapidly increases due to oxidation of the copper conductor and the surface of the electrode plate, and it is easy to burn out by heating. Therefore, the current density is at most 500 A / At present, it can only be increased to about ² m2, and in order to operate at a higher current density, the development of a new method had to be awaited.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems. As a result, the inventors have devised to control the temperature rise of the copper conductor to a certain temperature or less.
A current density exceeding 500 A / m ² , for example, a current density of 5
It has been found that even at 50 A / m ² or more, and even 600 A / m ² or more, it is possible to operate satisfactorily without any trouble, and to provide the present invention.

That is, in one aspect of the present invention, in an electrolysis method for electrolytically extracting zinc from a zinc sulfate solution using an aluminum plate as a cathode and a lead alloy plate as an anode, the present invention is provided at a side edge of a battery case. The copper conductor (bus bar) is cooled at a predetermined temperature determined by preliminary tests, theoretical calculations, or the like by cooling the copper conductor continuously, intermittently, or as needed, by forced cooling means such as watering. An object of the present invention is to provide a zinc electrolytic smelting method characterized in that electrolysis is performed at a high current density exceeding 500 A / m ² while not exceeding the value.

[0007] The predetermined temperature is, for example, 100 ° C.
It was confirmed that it was a rough guide. That is, 10
It has been confirmed that electrolysis can be continued at a high current density of 550 A / m ² or more, and more preferably 600 A / m ² or more if the operation is performed while cooling the copper conductor so as not to exceed 0 ° C. If the above-mentioned predetermined temperature is further lowered, for example, 90 ° C., troubles are less likely to occur, but it is necessary to increase the amount of water for forced cooling.

[0008] 500 A / m ² is the current density which was temporarily set to the upper limit in the conventional high current density electrolysis, and the present invention breaks this wall and enables electrolysis at a much higher ultra-high current density. Technology. Therefore, in the broadest claim, the current density is set to "beyond 500 A / m ² ".
Specifically, a high current density electrolysis of 550 A / m ² or 600 A / m ² was performed, and a satisfactory result was obtained.

As described above, the essence of the technical idea of the present invention is that if the copper conductor is operated to maintain the temperature below an appropriate set temperature by the forced cooling means, the conventional upper limit of the current density is 500 A. It has been discovered that zinc electrolytic smelting can be stably performed for a long time even at a high current density which is significantly higher than / m ² . Therefore, the selection of the water spray method as the forced cooling means is merely an example, and other known cooling means, for example, a method of blowing cooled air can be employed. Setting the target value of cooling to 100 ° C. or lower or 90 ° C. or lower is merely one specific example, and is not a limitation of the invention.

Further, the present invention provides an example of a specific apparatus for applying the above technical concept to actual zinc electrolytic smelting.
An apparatus according to claim 2 is provided. In the apparatus, the electrolytic cell in which strip-shaped copper conductors are provided on both side edges is an electrolytic cell used in normal zinc electrolytic smelting and is not special at all, and the copper conductor is forcibly cooled. As an example of the means, a water tube capable of spraying cooling water with an automatic timer is provided on the copper conductor, which is a feature different from a normal electrolytic cell. Actually, furthermore, a partition plate is provided between the electrolytic cell and the copper conductor, and structural considerations are taken such that the cooling water flows out to the lower part of the conductor, but this enhances the cooling effect economically. This is not a structural limitation.

[0011]

According to the experiment, it has been found that when the temperature of the copper conductor exceeds 100 ° C., the contact resistance rapidly increases due to the surface oxidation of the contact portion, and it is easy to burn by heating. In the method of the present invention, cooling water is arbitrarily sprayed from a water pipe connected to an automatic timer,
Normally, the temperature of the copper conductor was always kept at 90 ° C. or lower.

At the same time, the ends (ears) of the electrode plate are also washed with the cooling water, so that the scale of gypsum or the like generated at the end of the electrode plate due to evaporation of water in the electrolytic solution can be prevented.

[0013] Due to these facts, conventionally, at most 50.
What could be operated only at a high current density of about 0 A / m ² can be increased to a high current density of 600 A / m ² or more, so that low-cost nighttime power can be used significantly. Became.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the scope of the present invention is not limited thereto.

[0015]

Embodiment 1 FIG. 1 is a plan view of an electrolysis apparatus according to the present invention. This apparatus includes an electrode plate 2 in an electrolysis tank 1, that is, an aluminum plate as a cathode and a lead alloy plate as an anode. The suspension was alternately suspended in the electrolytic solution, and a high current was supplied to the copper conductor 3 for electrolysis. On the copper conductor, a hose as a water pipe 5 for watering interlocked with an automatic timer (not shown) was installed.

While the copper conductor 3 is energized at a current density of 600 A / m ² , when the electrode plate is left standing from the water pipe 5 for spraying, 2.
Cooling water was sprinkled on the copper conductor 3 at a rate of 4 m ³ / hr,
The temperature of the copper conductor was maintained at 50 ° C., and when the electrode plate was pulled up, the amount of water sprayed was 5.4 m ³ / hr to prevent the formation of an oxide film on the electrode plate surface and the occurrence of sparks due to scale. . As a result, it was possible to increase the operation rate by 8% without increasing any trouble in operation, and to increase the nighttime power utilization rate by 2.8%.

[0017]

Comparative Example 1 Using the same apparatus as in Example 1, current was supplied at a current density of 600 A / m ² . However, unlike Example 1, a change in the copper conductor temperature and the room temperature of the electrolysis every hour were conducted by applying electricity without spraying cooling water, and the results are shown in FIG. As a result, the temperature of the copper conductor rose to 110 ° C. one hour after energization. Further, it was confirmed that the room temperature of the electrolysis also increased from 30 ° C. to 45 ° C. after 5 hours. As a result, an oxide film was formed on the surface of the copper conductor and the electrode plate.

[0018]

As described above, according to the present invention, it is possible to conduct electricity at a high current density by maintaining the rising temperature of the copper conductor at a predetermined temperature or less by automatic watering, and to use a large amount of inexpensive night current. As a result, cost-effective operations can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view of the device of the present invention.

FIG. 2 is a partially enlarged perspective view of the device of the present invention.

FIG. 3 is a diagram showing changes in the temperature of a copper conductor and an electrolyte solution when a high current density (600 A / m ² ) is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolyzer 2 Electrode plate 3 Copper conductor 4 Electrolyte 5 Watering tube

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-54101 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25C 1/00-7/08

Claims (2)

(57) [Claims] 1. An electrolysis method for electrolytically extracting zinc from a zinc sulfate solution using an aluminum plate as a cathode and a lead alloy plate as an anode, wherein a copper conductor provided at a side edge of a battery case is continuously cooled by forced cooling means. Characterized by performing electrolysis at a high current density exceeding 500 A / m ² while keeping the copper conductor from exceeding a predetermined temperature by cooling periodically, intermittently or as needed. Law. 2. A zinc electrolysis apparatus comprising an electrolytic cell provided with strip-shaped copper conductors on both side edges and electrode plates of a cathode and an anode suspended in the cell, wherein an automatic timer is provided on the copper conductor. A zinc electrolysis apparatus characterized in that a water pipe through which cooling water can be sprayed is provided.