JPH11246989A - Electrolytic refining method of copper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the cutting of the hanging portions of a cathode by corrosion and to obviate the occurrence of an excess electric power cost occurring in the increase of a cell voltage by the enlargement of a distance between plates after replacement of the cathode which is heretofore carried out. SOLUTION: An anode life is coincided with a cathode life, and the operation not executing the replacement of the cathode in the second half of the anode life is carried out. Namely, an insoluble cathode mother plate is used as the cathode or a seed plate reinforced in the hanging portion is used as the cathode and the energization to the cathode is executed till the time corresponding to the anode life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for electrolytically refining metals such as copper, and more particularly, to an electrolytic refining method for saving labor in operation and reducing power costs.

[0002]

2. Description of the Related Art In the electrorefining of metals such as copper, a crude metal is used for an anode, a thin plate of a target metal is used for a cathode, and the metal eluted from the anode is electrodeposited on the cathode. Withdraw the cathode that has become a quality metal plate. On the cathode, a hanging portion for hanging the cathode in the electrolytic solution of the battery case is provided at an upper portion, and the hanging portion is hung on a cross beam.

[0003] In this case, if the electrodeposition is continued for a long time, there is a possibility that an accident may occur in which the hanging portion is cut by acid erosion. Therefore, the anode life is 1/3 to 1 /
After the elapse of the second time, the cathode was withdrawn, and instead, a new cathode made of a thin metal plate was charged, and the operation of supplying electricity again was performed. However, replacing the cathode increases the number of operation steps and increases the operation time.

[0004] In electrolytic refining, the metal is eluted from the anode and becomes thinner, and the metal is electrodeposited on the cathode and becomes thicker. Therefore, the distance between the plates between the anode and the cathode is almost constant. After replacement of the cathode, the initial thickness of the new cathode is less than the thickness of the raised cathode, thus increasing the distance between the plates. As a result,
There has been a problem that the tank voltage increases and the power cost increases accordingly.

[0005] Further, by pulling up the cathode from the battery tank containing the electrolyte and placing a new cathode, the slime on the anode surface and the tank bottom is stirred and floated.
Since the slime adhering to the newly arranged cathode surface may cause contamination (contamination) of particles and impurities, it is not preferable to replace the cathode from the viewpoint of maintaining quality. .

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to prevent the cathodic hanging portion of the cathode from being cut by acid erosion in the electrolytic refining process. It is an object of the present invention to prevent generation of extra power cost caused by an increase in cell voltage due to an increase in the distance between plates.

[0007]

In order to solve the above-mentioned problems, in the method of the present invention, the anode life and the cathode life are made to coincide with each other, and the operation is performed without replacing the cathode in the latter half of the anode life. .

That is, in the method for electrolytically refining copper of the present invention, an insoluble cathode base plate is used as a cathode, or a seed plate having a reinforced hook portion is used as a cathode, and until a time corresponding to the anode life is reached. Energize the cathode.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to prevent an increase in the cell voltage in the latter half of the anode life and stirring of the electrolytic solution due to replacement of the cathode, the anode life and the cathode life may be made to coincide with each other and the cathode life may be raised at the same time. However, it is not preferable to make the anode thinner in accordance with the thickness of the cathode in order to match the anode life with the cathode life in terms of handling in the refining process and an increase in the amount of repeated anode scrap. That is, the cathode life should be adjusted to the anode life.

In the first place, the anode-cathode distance exceeding a certain value necessary for circulating the electrolyte evenly to obtain good electrodeposition or to settle to the bottom of the tank without catching the slime, Because it is sufficiently open at times and is almost constant throughout the operation,
At this point, there is no need to replace the cathode.

If the cathode having the conventional shape is used for a long time, the hanging portion may be cut off. Therefore, a method of increasing the thickness of the hanging portion can be considered.

Further, in the copper electrolysis method of the present invention, an insoluble cathode base plate is repeatedly used as a cathode, and an anode energization time and a cathode energization time are made equal.
That is, an insoluble cathode mother plate is repeatedly used as a cathode.

[0013]

EXAMPLES Copper was electrorefined in the following tank A according to the method of the present invention.

A battery container having a length of 3000 mm, a width of 1260 mm and a depth of 1350 mm was prepared, and was designated as A tank. A purified anode (width 1030 mm, length 1050 mm,
27 sheets of 38 mm thick, single weight of 370 kg) and a stainless steel cathode base plate (electrodeposited part width 1070 mm, length 105
0mm, thickness 3mm, material SUS304L, single weight 40k
g) 26 sheets were alternately charged so that the distance between the anodes was 105 mm.

An electrolytic solution having a Cu concentration of 50 g / L, a sulfuric acid concentration of 180 g / L and a liquid temperature of 60 ° C. was passed through the tank A at a rate of 15 L / min. As an additive, electrodeposited copper amount 1
80 g of glue and 60 g of thiouric acid were continuously added to the liquid per ton. The conduction current was 14,600 A.

In the tank A, electricity was supplied without lifting the cathode for 480 hours from the start of electricity supply. While energized,
Changes in cell voltage were continuously recorded and averaged over one day in Fig. 1.
Are plotted.

For comparison, electrolytic refining of copper was carried out in the following conventional B tank.

A battery case having a length of 3000 mm, a width of 1260 mm and a depth of 1350 mm was prepared and used as a B tank. A purified anode (width 1030 mm, length 1050 mm,
27 sheets of thickness 38mm, unit weight 370kg, and seed plate cathode (width 1070mmm, length 1050mm, thickness 0.7m)
m, initial unit weight 7 kg) were alternately charged so that the distance between the anodes was 105 mm, similarly to the A tank.

The passed electrolyte, the additive, and the current
It was exactly the same as in the case of the tank A.

In the tank B, the cathode was pulled up 240 hours after the start of energization, the electrodeposition plate was peeled off from the cathode, the cathode was charged again, and energization was continued for 240 hours. During energization, changes in cell voltage were recorded continuously and plotted in FIG. 1 as daily averages.

In the tank A of the method of the present invention, as shown in FIG. 1, almost no increase in the tank voltage was observed even in the latter half of the energization, and the average of 50 m compared to the tank B of the conventional method.
The voltage of the tank becomes higher than V, and the power cost can be reduced accordingly. In addition, in the entire energizing time, B
While the average of the tank voltage of the tank is 295 mV, the average of the tank voltage of the tank A of the embodiment of the present invention is 270 mV,
Since the flowing current was constant, the saved electrolysis power reached 8.5%.

However, even in the case of the tank B, the hanging portion of the cathode is thickly reinforced, and 480 minutes from the start of energization as in the case of the tank A.
When the cathode was left without being lifted for a time, the same result as in the case of the A tank was obtained.

[0023]

According to the method of the present invention, the replacement of the cathode is not performed, so that the labor is omitted and a high quality metal plate can be obtained. In addition, it is possible to prevent the hanging portion of the cathode from being cut by acid corrosion, suppress a rise in cell voltage, and perform an operation with reduced power cost.

By making the insoluble cathode base plate used in the method of the present invention heavier than the initial weight of the seed plate cathode of the conventional method, the contact resistance of the contact with the cross beam is small even at the beginning of energization. There is also an effect that the power loss in the part can be reduced, and the power cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change over time of a cell voltage in an embodiment of a method of the present invention and an embodiment of a conventional method.

Claims (2)

[Claims] 1. A method for electrolytically refining copper, comprising using an insoluble cathode mother plate as a cathode and energizing the cathode for a time corresponding to the anode life. 2. A method for electrolytically refining copper, comprising using a seed plate having a reinforced hanging portion as a cathode and energizing the cathode for a time corresponding to the anode life.