JP3208927B2 - Electrorefining method for non-ferrous metals - Google Patents

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 non-ferrous metals such as copper and nickel.

[0002]

2. Description of the Related Art When electrolytically refining copper or nickel, electrolysis is performed by alternately inserting 20 to 30 anodes and cathodes into one tank. When the electrodeposition layer is formed to a certain thickness on the cathode, the anode is left as it is, and the electrolyzed cathode is replaced with the pre-electrolysis cathode to continue the electrolysis.

In order to replace the electrolyzed cathode with the pre-electrolysis cathode, usually, half of the electrolyzed cathode in one cell is pulled out of the electrolysis tank, and then the same number of pre-electrolysis cathodes as the withdrawn electrolyzed cathode is inserted. Shortly thereafter, the other half of the electrolyzed cathode is replaced with a pre-electrolysis cathode.

[0004] To replace the cathode, a hacker suspending a plurality of pre-electrolysis cathodes is moved over the electrolytic cell, and a hanging tool between the pre-electrolysis cathodes is lowered onto the electrolyzed cathode, and the electrolysis is performed. The cathode is lifted, then the pre-electrolysis cathode is moved to the insertion position in the electrolyzer, lowered and inserted into the electrolyzer, and the lifting tool is lifted. It takes at least 15 minutes for the cathode to be inserted into the electrolytic cell.

[0005] During this time, the cathode current density of the just-inserted pre-electrolysis cathode doubles, so that this cathode is then electrolyzed at a predetermined cathode current density to the surface of the electrolyzed cathode, in the form of particles or powdery electrodeposits. And the problem of deteriorating the appearance quality of the electrodeposited product occurs.

In order to avoid such a situation, when replacing the latter half cathode, it was necessary to stop the current supply or reduce the current supply. However, there is a problem that the electrolyzer also loses power or the current decreases, and the electrodeposition speed decreases. It is necessary to change the connection one by one in order to prevent the other electrolyzer from power failure, but changing the connection for each replacement tank complicates the work.

[0007]

SUMMARY OF THE INVENTION According to the present invention, when replacing one half of the electrolyzed cathode in one tank in the electrorefining process with a pre-electrolysis cathode, a predetermined current is supplied to the electrolysis tank and the surface of the electrolyzed cathode is removed. An object of the present invention is to provide a method for preventing generation of particles or powdery electrodeposits.

[0008]

SUMMARY OF THE INVENTION According to the present invention, when replacing an electrolyzed cathode of one electrolytic cell with a pre-electrolytic cathode, half of the electrolyzed cathode of the electrolytic cell is pulled up from the electrolytic cell, and then the same number Insert the pre-electrolysis cathode into the electrolytic cell, and perform electrolysis for a predetermined time or more according to the magnitude of the cathode current density when performing electrolysis at a predetermined cathode current density by inserting all anodes and all cathodes into the electrolysis tank, Thereafter, the remaining half of the electrolyzed cathode is replaced with a pre-electrolysis cathode, and electrolysis is performed at the predetermined cathode current density.

[0009] The present invention is also when replacing the electrolyte already cathode of one electrolytic cell and before the electrolysis cathode, the electrolyte already cathode half of the electrolyzer lifted from the electrolytic cell, then the electrolyte already cathode same number of raised Caso before electrolysis
Insert all anodes and cathodes into the electrolytic cell
Current density when performing electrolysis at a predetermined cathode current density
Electrolyzed in another electrolytic cell for more than a predetermined time according to the magnitude of the degree
Cathode or electroless plated cathode in electrolyzer
Insert and then remove the remaining half of the electrolyzed cathode before electrolysis.
In place of the cathode, electrolysis is performed at the predetermined cathode current density.

[0010]

In the electrolysis, while the current is small, the cathode surface is electrodeposited smoothly. However, as the current increases, a portion where the current density is locally increased on the cathode surface, and the current in that portion is increased. The deposition rate increases, and as a result, particles and the like are generated, making it impossible to obtain uniform electrodeposition with a smooth surface. When performing electrolysis, usually, electrolysis is performed from the beginning by applying a current having a cathode current density equal to or less than a range where smooth electrodeposition occurs to a cathode inserted into an electrolytic cell.

In view of this point, the present invention focuses on electrolysis at a predetermined cathode current density by inserting half of the pre-electrolysis cathodes initially inserted into the electrolytic cell and inserting all the anodes and all the cathodes into the electrolytic cell. If electrolysis is performed for a predetermined time or more according to the cathode current density, the surface is electrodeposited smoothly, and thereafter, the remaining half of the electrolyzed cathode is pulled up, and then the remaining half of the pre-electrolysis cathode is inserted. In addition, it has been found that even if a current having a density twice as high as a predetermined cathode current density flows through half of the pre-electrolysis cathodes initially inserted in the electrolytic cell, a cathode whose surface is electrodeposited smoothly can be obtained. .

Based on this finding, when all the anodes and all the cathodes are inserted into the electrolytic cell and electrolysis is performed at a predetermined cathode current density, a predetermined time or more is applied according to the magnitude of the cathode current density.
It can also be seen that when the cathodes electrolyzed in another electrolytic cell are used as the pre-electrolysis cathodes for half of the cells to be inserted first, a cathode whose surface is electrodeposited with a smooth surface is similarly obtained . Here, the predetermined time , when electrolysis at a predetermined cathode current density,
If it is less than that time, smooth electrodeposition cannot be obtained,
After this, the time required for smooth electrodeposition to be obtained
U.

In the case of copper electrolysis, there are a case where the cathode plate is made into a product and a case where the electrodeposited plate is peeled off from the cathode plate to make a product. In the latter, copper plate and stainless steel,
Electrodeposition is performed by applying a release agent to the titanium plate, but the throwing power is inferior to the case of electrodepositing on the cathode of the copper plate to make the product as it is, so when replacing half of the cathode before electrolysis later There is a problem that the surface smoothness of the electrodeposited cathode is inferior due to the applied high current density.

In the latter case, this problem can be solved by previously electrolyzing in another electrolytic cell or by electroless plating to form a copper film as described above.

[0015]

EXAMPLES Copper seed plate electrolysis was performed as follows. SUS304L stainless steel plate (electrodeposited area 105
Using 24 sheets of 0 × 1070 mm, thickness 3 mm) and 25 pieces of purified copper anode plate (1040 × 1026 × 35 mm), liquid temperature 60 ° C., copper 45 g / l, sulfuric acid 190 g / l, glue addition amount 80 g / electrodeposition Using an electrolytic solution with a composition of copper tons,
Electrolysis was performed in an electrolytic cell having an inner surface size of 1260 × 3000 × 1360 mm.

A cathode and an anode were alternately inserted into the electrolytic cell, and electrolysis was performed at a predetermined cathode current density for a predetermined time. Then, without changing the energizing current, half of the 12 cathodes were pulled up, and energization was performed for 15 minutes so that the remaining 12 cathodes had a cathode current density twice the predetermined cathode current density.

Thereafter, 12 cathodes were inserted so that the cathode current density became a predetermined value. After energizing for 22 hours in this way, the cathode was pulled up from the electrolytic cell, the electrodeposited copper plate was peeled off, and the surface state of the electrodeposited copper plate, which had twice the cathode current density on the way, was observed. The electrolysis situation was judged good or bad. Table 1 shows the results.

[0018]

Table 1 Test Predetermined electrolysis Predetermined cathodic current Doubled cathodic current Electrodeposition time (min) Density (A / m ² ) Density (A / m ² ) 10 160 320 Smooth 2 0 175 350 Smooth 30 200 200 grains Generation 4 2 200 400 Smooth 5 2 216 432 Smooth 6 2 230 460 Grain generation 7 15 200 400 Smooth 8 15 230 460 Smooth 9 15 240 480 Grain generation 10 30 225 450 Smooth 11 30 235 470 Smooth 12 30 250 500 500 45 240 480 Smooth 14 45 250 500 Smooth 15 45 260 520 Grain generation 16 60 235 470 Smooth 17 60 240 480 Smooth 18 60 260 520 Grain generation 19 90 240 480 Smooth 20 90 260 520 Smooth 21 90 265 230 120 0 480 smooth 23 120 250 500 smooth 24 120 265 530 grains occurs

In Table 1, for example, in Test Nos. 7 and 8, the predetermined cathode current densities are 200 and 230 A / m, respectively.
^{In step 2} , electrodeposition can be obtained smoothly with a predetermined electrolysis time of 15 minutes. However, even if the predetermined cathode current density is set to 240 A / m ² as in Test No. 9 even in the predetermined electrolysis time, grain formation can be observed. However, even if the predetermined cathode current density is 240 A / m ² ,
If electrolysis is performed for 45 minutes or more as in Test No. 13, electrodeposition can be performed smoothly. That is, the pre-electrolysis cathode first inserted into the electrolytic cell, a predetermined time or more according to the magnitude of the cathode current density when performing electrolysis at a predetermined cathode current density by inserting all the anodes and all the cathodes into the electrolysis tank It can be seen that by performing electrolysis, a smooth electrodeposited layer can be formed even when the electrolysis is performed at twice the cathodic current density.

[0020]

According to the method of the present invention, when half of the electrolyzed cathodes in one cell are replaced with each other before the electrolysis, a predetermined current is supplied to the electrolysis cell and the surface of the electrolyzed cathode can be formed smoothly.

Claims (1)

(57) [Claims] 1. When replacing an electrolyzed cathode of one electrolytic cell with a pre-electrolytic cathode, half of the electrolyzed cathode of the electrolytic cell is pulled up from the electrolytic cell, and then pulled up.
As many pre-electrolysis cathodes as
Insert the anode and all cathodes into the electrolytic cell and
Depending on the size of the cathode current density when performing electrolysis at the current density
The cathode has been electrolyzed in another electrolytic cell for more than
Insert the electrolessly plated cathode into the electrolytic cell, and then
Insert the remaining half of the electrolyzed cathode with the pre-electrolysis cathode.
Alternatively, a method for electrolytically refining non-ferrous metals , wherein electrolysis is performed at the predetermined cathode current density.