JPH06212472A - Zinc electrolytic refining method and device therefor - Google Patents

Abstract

PURPOSE:To enable energizing in high current density by keeping the temp. of a copper conductor arranged at a side edge part of an electrolytic cell below a prescribed value by cooling the copper conductor with a forcedly cooling means. CONSTITUTION:Electrode plates 2 are hung in an electrolytic soln. 4 in the electrolytic cell 1 and an electrolysis is executed by energizing high electric current through the copper conductor 3. The copper conductor 3 is cooled by intermittently sprinkling water from a water tube 5 for sprinkling water. Since contacting parts are subjected to surface-oxidation and contact resistance rapidly increases to be easy to burn out by heating when the temp. of the copper conductor 3 exceeds 100 deg.C, the temp. of the copper conductor 3 is kept below 90 deg.C by forcedly cooling. Since the edge parts of the electrode plates are washed by cooling water at the same time, generation of scales such as gypsum generating from the electrolytic soln. 4 at the edge parts of the electrode plates are prevented. Consequently, operation can be run in hight current density over 500A/m<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high current density operation in electrowinning of zinc smelting, and more specifically, it has been set as an upper limit value in conventional high current density zinc electrolysis while controlling the temperature of a copper conductor. Further exceeding 500 A / m ² , for example, 550 A / m ² or more, or even 60
The present invention relates to a method and an 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 zinc electrowinning process in Japan, a method of electrolyzing at high current density at night using a large amount of nighttime electric power whose unit price is low has been widely adopted. However, even in this case, the current density generally used is at most about 500 A / m ² .
Therefore, from the viewpoint of further intensive use of nighttime electric power, it has been desired to further increase the current density and further increase the nighttime operation rate.

However, in the current zinc electrolysis method, 50
When operating at a high current density of 0 A / m ² or more, the temperature of the electrode plate contact part and the copper conductor rises sharply, so that an oxide film is likely to form on these surfaces, and with this, the electrode plate and copper There has been a problem that the conductor itself is significantly worn. Further, since the electrolytic solution in the electrolytic cell is a sulfuric acid acid solution, as the electrolytic solution temperature rises, steam is generated and scales such as gypsum are generated on the electrode plate. There is also a problem that a large current flows through the electrode plate of the part to generate a spark.

[0004]

As described above, in the conventional high current density operation, the contact resistance abruptly increases due to the oxidation of the copper conductor and the surface of the electrode plate, and it is easy to burn by heating. Therefore, the current density is at most 500 A / At present, it is only possible to raise it to about m ² , and in order to operate at a higher current density, it was necessary to wait for the development of a new method.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve such problems, and found that the temperature rise of the copper conductor was controlled to be below a certain temperature.
A current density exceeding 500 A / m ² , for example, a current density of 5
It has been found that the present invention can be provided by finding out that even if it is 50 A / m ² or more, and further 600 A / m ² or more, it can operate sufficiently without any trouble.

That is, in one aspect, the present invention is provided in a side edge portion of a battery case 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. By cooling the copper conductor continuously, intermittently, or as needed at any time by means of forced cooling, such as by spraying water, the copper conductor (bus / bar) is heated to a predetermined temperature determined by preliminary tests or theoretical calculations. The present invention provides a zinc electrolytic smelting method characterized in that electrolysis is performed at a high current density of more than 500 A / m ² while not exceeding the limit.

The predetermined temperature is, for example, 100 ° C.
It was confirmed that is a tentative standard. Ie 10
It was confirmed that the electrolysis can be continued without a problem at a high current density of 550 A / m ² or more, and further 600 A / m ² or more if the copper conductor is cooled and operated so as not to exceed 0 ° C. If the above-mentioned predetermined temperature is further lowered, for example, to 90 ° C., troubles are less likely to occur, but it is necessary to increase the amount of water for forced cooling.

500 A / m ² is a current density which has been set as an upper limit value in the conventional high current density electrolysis, and the present invention breaks this wall and enables electrolysis at a higher ultrahigh current density. It is a technology. For this reason, in the broadest claim, the current density is “over 500 A / m ² ”.
However, specifically, satisfactory results have been obtained by performing high current density electrolysis of 550 A / m ² or 600 A / m ² .

As described above, the essence of the technical idea of the present invention is 500 A, which is the upper limit value of the conventional current density, when the copper conductor is operated by the forced cooling means so as to be kept below the appropriate set temperature. It was discovered that zinc electrolytic smelting can be stably performed for a long time even at a high current density significantly exceeding / m ² . Therefore, the selection of the sprinkling method as the forced cooling means is only an example, and other known cooling means, for example, a method of blowing cooled air or the like can be adopted. Setting the cooling target value to 100 ° C. or lower, or 90 ° C. or lower is merely one specific example and is not a limiting requirement of the invention.

Furthermore, the present invention provides an example of a concrete apparatus for applying the above technical idea to actual zinc electrolytic smelting.
An apparatus according to claim 2 is provided. The electrolytic cell in which strip-shaped copper conductors are arranged on both side edges of the apparatus is an electrolytic cell used in ordinary zinc electrolytic smelting and is not special, and the copper conductor is forcibly cooled. As an example of the means, a feature that is different from a usual electrolytic cell is that a water pipe capable of spraying cooling water with an automatic timer is provided on the copper conductor. In fact, a partition plate is provided between the electrolytic cell and the copper conductor, and structural consideration is given so that cooling water flows out to the bottom of the conductor, but this enhances the cooling effect economically. This is one of the ways to do so, and is not a structurally limiting condition.

[0011]

According to the experiment, it has been found that when the temperature of the copper conductor exceeds 100 ° C., the contact resistance abruptly increases due to the surface oxidation of the contact portion, and is easily burned by heating. In the method of the present invention, the cooling water is sprayed arbitrarily from the water pipe connected to the automatic timer,
Usually, the temperature of the copper conductor is always maintained at 90 ° C or lower.

At the same time, since the ends (ears) of the electrode plate are also washed with the cooling water, it is possible to prevent scales such as gypsum that are generated at the ends of the electrode plate due to evaporation of water in the electrolytic solution.

Due to these reasons, in the past, at most 50
What could only operate at high current densities up to 0 A / m ² can now be increased to high current densities of 600 A / m ² or more, so that low-cost nighttime electricity can be used meaningfully. 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]

EXAMPLE 1 FIG. 1 is a plan view of an electrolysis apparatus according to the present invention. In this apparatus, an electrode plate 2 is provided in an electrolysis cell 1, that is, an aluminum plate as a cathode and a lead alloy plate as an anode. They were alternately suspended in an electrolytic solution, and a high current was passed through the copper conductor 3 for electrolysis. A hose was installed on the copper conductor as a water pipe 5 for sprinkling in conjunction with an automatic timer (not shown).

The copper conductor 3 is energized at a current density of 600 A / m ² , while the electrode plate is left stationary from the water pipe 5 for sprinkling.
Cooling water is 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, water was sprinkled at a rate of 5.4 m ³ / hr to prevent generation of oxide film on the surface of the electrode plate and generation of sparks by scale. . As a result, the operation was completed without any trouble, and the operating rate could be increased by 8%, and the night power utilization rate could be increased by 2.8%.

[0017]

[Comparative Example 1] Using the same device as in Example 1, electricity was applied at a current density of 600 A / m ² . However, unlike Example 1, changes in copper conductor temperature and electrolysis room temperature were checked every hour by energizing without spraying cooling water, and shown in FIG. As a result, the copper conductor was heated up to 110 ° C. in 1 hour after energization. It was also confirmed that the electrolysis room temperature also increased from 30 ° C to 45 ° C after 5 hours. Along with this, an oxide film was generated on the surfaces of the copper conductor and the electrode plate.

[0018]

As described above, according to the present invention, it is possible to energize the copper conductor 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 nighttime current. As a result, it became possible to operate cost-effectively.

[Brief description of drawings]

FIG. 1 is a plan view of a 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 copper conductor and electrolytic solution temperature during energization at high current density (600 A / m ² ).

[Explanation of symbols]

 1 Electrolyzer 2 Electrode plate 3 Copper conductor 4 Electrolyte 5 Water pipe for watering

Claims (2)

[Claims] 1. 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, a copper conductor provided at a side edge portion of a battery case is continuously subjected to forced cooling means. Zinc electrolytic smelting characterized by performing electrolysis at a high current density of more than 500 A / m ² while preventing 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 having strip-shaped copper conductors on both side edges and cathode and anode electrode plates suspended in the cell, wherein an automatic timer is provided on the copper conductor. A zinc electrolysis device characterized in that a water pipe capable of spraying cooling water is provided.