JP2008308744A - Copper electrolysis method in acidic chloride bath - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper electrolysis method which can provide an electrodeposit having superior smoothness by using an electrolytic solution of an acidic chloride bath containing copper and is superior in safety and economy. <P>SOLUTION: This copper electrolysis method for providing the electrodeposit having superior smoothness by using the electrolytic solution of the acidic chloride bath containing copper includes: supplying the electrolytic solution to an electrolytic tank provided with a cathode and an anode; continuously passing an electric current to the electrolytic tank; and controlling an effective energization rate to 50 to 90%, which is determined by dividing a current-passing period by the total period of time of the current-passing period and the current-stopping period in one cycle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a copper electrolysis method in an acidic chloride bath. More specifically, the present invention is excellent in safety and economical efficiency in which an electrodeposit excellent in smoothness can be obtained from an electrolytic solution comprising an acidic chloride bath containing copper. The present invention relates to a copper electrolysis method.

  Conventionally, the copper electrolysis method has been used as a method for obtaining high-purity copper by separating impurity elements when refining crude copper obtained from ore by a dry copper smelting method such as smelting. In addition, recently, smelting by a wet method has been attempted in consideration of energy and environmental aspects by a dry copper smelting method. Here, in the hydrometallurgical method, copper is leached from ore using sulfuric acid or hydrochloric acid, and copper is recovered from the leachate by electrolytic collection.

  As a leachate for such a hydrometallurgical process, a sulfuric acid bath based on sulfuric acid and a chloride bath based on hydrochloric acid or chloride are usually used. Here, when leaching in a sulfuric acid bath, the copper ions in the leaching solution are in a divalent form. On the other hand, in the case of a chloride bath, the copper ions in the leachate can take both monovalent and divalent forms. By the way, in electrolysis, since monovalent copper ions can be metallized with half the electric power of divalent copper ions, the energy saving effect is remarkably large. However, in the case of electrolytic deposition in a sulfuric acid bath, an electrodeposit having a smooth electrodeposition surface can be obtained by using an appropriate amount of additive, whereas electrolytic deposition from a chloride bath is acicular. It is known that there is a problem that an electrodeposit having a smooth electrodeposition surface cannot be obtained, particularly when electrolysis is performed at a high current density in order to increase productivity.

  For this reason, a method for producing an electrodeposit on a dentite (see, for example, Patent Document 1) has been disclosed. Electrodeposition of such needle-like or granular electrodeposits causes a short circuit during electrolysis. Electricity loss is likely to occur, and the labor of the inspection tank is increased. In addition, since such electrodeposit falls from the cathode and deposits on the bottom of the tank, a recovery facility from the bottom of the tank is necessary, and there is a possibility of sticking into the hand during handling, which is also a problem in terms of safety management. . Furthermore, at present, electrolytic copper is generally traded in the form of a cathode in the market. Therefore, in the case of acicular or granular electrolytic copper, troubles such as storing in a case or remelting are required. This is not advantageous in terms of cost.

  In general, in order to obtain an electrodeposit having a smooth electrodeposition surface, an additive is used in the electrolytic solution. Since additives are rapidly decomposed in an acidic atmosphere such as by chlorine gas generated from the anode, it has been considered that the use of organic additives is not effective. Moreover, the possibility that harmful substances are generated by the reaction between the decomposed organic substance and chlorine gas cannot be completely denied, and there is a concern that the characteristics of the decomposed organic substance deteriorate due to covering the surface of the insoluble electrode. By the way, although additives such as glue generally used in a sulfuric acid bath are effective in a trace amount of several mg / L, they are sensitive to their excess and deficiency and difficult to manage. Moreover, since there are many factors that affect the electrodeposition state in addition to the additive, many problems remain in the use and confirmation of effectiveness by analysis and the like.

  For example, in a copper electrowinning process from a halogen-based copper electrolyte, polyethylene glycol is added to the halogen-based electrolyte as a smoothing additive, and the halogen-based electrolyte near the cathode surface is electrolyzed with gas or mechanical stirring. Thus, in a method for producing dense plate-shaped electrolytic copper (see, for example, Patent Document 2), it is disclosed that plate-like copper can be produced even from a chloride bath by using polyethylene glycol or strengthening stirring. Has been. However, polyethylene glycol has a stable molecular weight, but on the other hand, it is difficult to control the liquid state, such as it is difficult to restore the current state when it is damaged and it enters excessively, so in copper electrolysis in a sulfuric acid bath, It is not used industrially. In this method, the electrolyte solution in the vicinity of the electrode is stirred at a large flow rate of 1 m / sec. However, considering the structure of the industrial electrolytic cell and the number of electrodes in the cell, such a large flow rate is required. There is a problem that the power cost cannot be ignored and the effect of reducing the power cost by monovalent electrolysis is reduced.

  From the above situation, obtaining an electrodeposit having a smooth electrodeposition surface from a chloride bath has not yet been put into practical use, and an electrode having excellent smoothness is obtained from an electrolytic solution comprising an acidic chloride bath containing copper. It has been demanded to manufacture a kimono by a method excellent in safety and economy.

Japanese Patent Laying-Open No. 2005-105351 (first page, second page) JP 2006-97128 A (first page, second page)

  In view of the above-mentioned problems of the prior art, an object of the present invention is to provide an electrodeposit excellent in smoothness from an electrolytic solution comprising an acidic chloride bath containing copper, and to provide a copper electrolysis excellent in safety and economy. It is to provide a method.

  In order to achieve the above object, the present inventors have conducted extensive research on a copper electrolysis method from an electrolytic solution comprising an acidic chloride bath containing copper. As a result of controlling the intermittent energization to the above, it has been found that an electrodeposit excellent in smoothness can be produced from an electrolytic solution composed of an acidic chloride bath containing copper at a low cost without safety problems. completed. The intermittent energization refers to periodically energizing and powering out every predetermined time while periodically interrupting power, thereby performing so-called pulse electrolysis.

That is, according to the first aspect of the present invention, there is provided a copper electrolysis method for obtaining an electrodeposit excellent in smoothness from an electrolytic solution comprising an acidic chloride bath containing copper,
The electrolytic solution was supplied to an electrolytic cell equipped with a cathode and an anode, and energization of the electrolytic cell was made intermittent, and the energization time was divided by the total time of the energization time and power outage time in one cycle. There is provided a copper electrolysis method characterized in that an effective energization rate is 50 to 90%.

  According to a second aspect of the present invention, there is provided the copper electrolysis method according to the first aspect, wherein the power failure time used for the intermittent energization is 30 seconds to 1 minute.

  According to a third invention of the present invention, in the first or second invention, the electrolytic solution is an acidic copper chloride aqueous solution (A) having a copper concentration of 40 g / L or more and a solubility limit or less. A featured copper electrolysis method is provided.

  According to a fourth invention of the present invention, in the first or second invention, the electrolyte solution has a copper concentration of 40 g / L or more and a solubility limit or less, and a weight average molecular weight ( A copper electrolysis method is provided which is an acidic copper chloride aqueous solution (B) containing glue or gelatin having a Mw) of 40,000 or less at a concentration of 0.1 to 1 g / L.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the electrolytic cell comprises a cathode chamber and an anode chamber in which the cathode and the anode are separated by a filter cloth diaphragm. A featured copper electrolysis method is provided.

  According to a sixth aspect of the present invention, in the fifth aspect, the liquid supply to the anode chamber is an acidic copper chloride aqueous solution (A), while the liquid supply to the cathode chamber is acidic copper chloride. A copper electrolysis method is provided which is an aqueous solution (B).

  According to the seventh invention of the present invention, in any one of the first to sixth inventions, the material of the cathode is copper, and the surface roughness is represented by a five-point standard roughness (Rz). A copper electrolysis method is provided in which the measured value is 5 to 20 μm.

  According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the width of the cathode is increased at a rate of 10 to 30% with respect to the width of the anode. An electrolysis method is provided.

  The copper electrolysis method in the acidic chloride bath of the present invention is excellent in smoothness from an electrolytic solution composed of an acidic chloride bath containing copper by making the energization to the electrolytic cell intermittently controlled to a specific effective current rate. Therefore, the industrial value of the copper electrolysis method is extremely high. Further, it is more advantageous to use a combination of the above-mentioned intermittent energization and the addition of a specific amount of glue or gelatin having a specific weight average molecular weight as an additive.

Hereinafter, the copper electrolysis method in the acidic chloride bath of the present invention will be described in detail.
The copper electrolysis method in the acidic chloride bath of the present invention is a copper electrolysis method for obtaining an electrodeposit excellent in smoothness from an electrolyte solution comprising an acidic chloride bath containing copper, the electrolyte solution comprising a cathode and an anode. The electrolysis cell was supplied and the electrolysis cell was energized intermittently, and the effective energization rate obtained by dividing the energization time by the total time of energization time and power outage time in one cycle was 50 to 90%. It is characterized by being.

  In the present invention, in a copper electrolysis method from an electrolytic solution comprising an acidic chloride bath containing copper, it is important to conduct intermittent energization in which the energization to the electrolytic cell is controlled to a specific effective energization rate. As a result, an electrodeposit excellent in smoothness can be produced from an electrolytic solution comprising an acidic chloride bath containing copper by a method excellent in safety and economy. In other words, it is not continuous energization that is generally performed, but by pulse electrolysis that is performed periodically while power is interrupted, by repeating melting of electrodeposited protrusions caused by energization at the time of power failure, electrodeposition The growth rate can be made uniform, and a smooth electrodeposition surface can be obtained as a whole.

  As an effective energization rate in intermittent energization used for the above-mentioned copper electrolysis method, it is 50 to 90%, and it is preferred that it is 60 to 90%. That is, the smaller the effective energization rate, the smaller the crystal grains of the electrodeposit, the smoothness of the electrodeposited surface is improved, and the generation of needle-like crystals in the periphery of the cathode can be suppressed. If it is less than 50%, it is the same as more than half of the electrolytic cell is inactive, and this takes more than twice the power, but it is more productive than electrodeposition by a general sulfuric acid bath that can provide smooth electrodeposition. The superiority in is lost. In addition, there was almost no difference in smoothness between 60% and 50% of the effective energization rate. On the other hand, a higher effective energization rate is preferable from the viewpoint of productivity. However, when it exceeds 90%, needle-like crystals are generated in the periphery of the cathode, and irregularities due to grains become conspicuous in the center.

  The power failure time used for the intermittent energization is not particularly limited, but is preferably 30 seconds to 1 minute. That is, when the power failure time is less than 30 seconds, initialization such as elimination of the liquid flow on the electrode surface cannot be completed sufficiently, and the smoothing effect is insufficient. On the other hand, even if the power failure time exceeds 1 minute, the productivity is lowered, for example, there is no smoothing effect and the power failure occurs.

  Although it does not specifically limit as electrolyte solution used for the said copper electrolysis method, Preferably copper concentration is 40 g / L or more and the range below a solubility limit, More preferably, it is 60 g / L or more and below a solubility limit. An acidic copper chloride aqueous solution (A) containing hydrochloric acid in a range is used. That is, when the copper concentration is less than 40 g / L, it is difficult to obtain a smooth electrodeposition surface. On the other hand, when the copper concentration exceeds the solubility limit, precipitates are generated in the electrolytic solution or as a salt on the cathode surface. It is deposited and cannot be electrolyzed. The relationship between the copper concentration and the smoothness will also be described in the following hull cell test.

  As an electrolytic solution used in the copper electrolysis method, an acidic copper chloride aqueous solution in which a smoothing agent is further added to the acidic copper chloride aqueous solution (A), for example, glue or gelatin having a weight average molecular weight (Mw) of 40,000 or less. An acidic copper chloride aqueous solution (B) contained at a concentration of 0.1 to 1 g / L can be used. Thereby, smoothness improves compared with the case where acidic copper chloride aqueous solution (A) is used by the smoothing effect of the said smoothing agent, for example, glue or gelatin. That is, smoothness can be further improved by combining the intermittent energization with the addition of a specific amount of such glue or gelatin as an additive.

Here, the effect of the smoothing agent will be described using a Hull cell test.
As described above, the use of additives in the chloride bath still has many problems in confirming and managing its effectiveness by analysis, etc., and its liquid management is significantly more difficult than in the case of a sulfuric acid bath. There was no proper technique. By the way, in electrolytic refining in a sulfuric acid bath, a method using a hull cell test, for example, Japanese Patent No. 3148115, is disclosed as one of the methods for controlling the electrodeposition state. It is shown that there is a good correlation with the surface roughness. By applying this, the hull cell test is used to measure the roughness of the surface condition on the cathode, and by finding the electrolysis conditions that minimize the surface roughness over a wide current density range, It was considered that the conditions were suitable for obtaining, and based on this, the electrolysis factors necessary for obtaining a smooth electrodeposition surface were examined.

  As a result, if the smoothing agent is contained at an appropriate concentration, for example, the electrolyte solution may contain glue or gelatin having a weight average molecular weight (Mw) of 40,000 or less at a concentration of 0.1 to 1 g / L. It has been found that, by adding, the effect as a smoothing agent can be exhibited even in a chloride bath. The details will be described in the following [Hull Cell Test with Chloride Bath Electrolyte].

[Hull cell test with electrolyte in chloride bath]
Hydrochloric acid adjusted with hydrochloric acid so that the copper concentration is 20-60 g / L using sodium chloride of reagent grade 1 as the test solution, the chloride concentration is 100 g / L with sodium chloride, and the pH is 1 An acidic copper chloride aqueous solution was used. In accordance with the test conditions, an additive such as glue was dissolved in a predetermined concentration and stirred well, and then placed in a hull cell tank (electrolysis tank). A commercially available 267 mL tank was used as the hull cell tank. As the anode, a copper plate having a thickness of 0.6 mm cut into a size of 65 × 65 mm was used. As the cathode, a commercially available copper plate for Hull Cell test was used.
In the test, a current of 2 A was applied for 1 hour while maintaining the liquid temperature at 60 ° C. No stirring was performed during energization. After energization, the cathode is lifted, the surface is washed with pure water and ethyl alcohol, and the surface roughness at a position where the current density on the cathode corresponds to ²⁰ to 800 A / m ² is measured with a stylus type surface roughness meter (maximum measured roughness). 30 μm), and the relationship between the hull cell roughness and the current density was determined.

FIG. 1 shows the relationship between the surface roughness of the cathode and the current density when no industrial glue is used and an electrolytic solution having a glue concentration of 1 g / L is used. Here, the copper concentration was 20, 40, and 60 g / L, and the result of the sulfuric acid bath was also shown for reference. In addition, industrial glue is normally used in copper electrolytic purification of a sulfuric acid bath. Further, as shown in FIG. 1, when no glue was added, the electrode was in a rough electrodeposition state where the surface roughness could not be measured when the copper concentration was 20 g / L. On the other hand, when the copper concentration is 40 to 60 g / L, the current density used in the industrial operation is approximately 100 to 400 A / m ² , and the surface roughness decreases, and the increase in the copper concentration is smooth. It turns out to be essential to get dressed. In addition, when 1 g / L of glue was added, the surface roughness was remarkably reduced, and smoothness comparable to the surface roughness in the sulfuric acid bath was obtained. In particular, when the copper concentration was increased to 60 g / L, smoothness was maintained even on the high current density side exceeding 400 A / m ² , and an appearance completely equivalent to that of the sulfuric acid bath was obtained. In addition, when the copper concentration exceeds 60 g / L, further improvement in smoothness can be expected. However, the upper limit is selected in consideration of the solubility of copper and the increase in cell voltage.

  FIG. 2 shows the relationship between the surface roughness of the cathode and the current density when no industrial glue is used and when an electrolytic solution having a glue concentration of 1, 0.1, 0.01 g / L is used. The copper concentration was 60 g / L, and the result of the sulfuric acid bath was also shown for reference. From FIG. 2, it can be seen that the smoothness does not decrease at a glue concentration of 0.1 to 1 g / L, but the smoothness from a high current density to a medium current density region decreases at 0.01 g / L. In addition, since the appropriate glue concentration in the case of a sulfuric acid bath is estimated to be 0.001 to 0.002 g / L, it is indispensable to use a considerably high concentration in order to obtain an effect in a chlorination bath. I understand that.

FIG. 3 shows the relationship between the surface roughness of the cathode and the current density when no industrial glue is added and an electrolyte containing gelatin, glue and crude glue at a concentration of 1 g / L is used. The copper concentration was 40 g / L, and the result of the sulfuric acid bath was also shown for reference. Here, Table 1 shows the weight average molecular weight (Mw) of the glue and gelatin used. Nika has a molecular weight depending on the degree of purification, but its influence was evaluated. Here, as a term for glue, powdered glue used in copper electrolytic purification of a sulfuric acid bath is referred to as industrial glue and is used separately from granular crude glue.
From FIG. 3, gelatin having a weight average molecular weight (Mw) of 40,000 or less improves smoothness at a higher current density than that of industrial glue, but there is a difference in the range of current density used in normal operation. small. On the other hand, it can be seen that a rough glue with a weight average molecular weight (Mw) larger than these decreases the smoothing effect on the high current density side. Further, if the weight average molecular weight is about 40,000 or less, smooth electrodeposition can be obtained even on the high current density side.

The electrolytic cell used in the copper electrolysis method is not particularly limited, but a diaphragm electrolytic cell composed of a cathode chamber and an anode chamber in which a cathode and an anode are separated by a filter cloth diaphragm can be used.
At this time, the supply liquid to the anode chamber is preferably an acidic copper chloride aqueous solution (A), while the supply liquid to the cathode chamber is preferably an acidic copper chloride aqueous solution (B). That is, since the anode chamber is highly oxidative, supplying an acidic copper chloride aqueous solution (B) not only oxidizes and decomposes organic matter such as glue and gelatin in the liquid, but also causes a risk of generating harmful components. Because there is also.

The material of the cathode used in the copper electrolysis method is not particularly limited, but copper is preferable. That is, in the case of a cathode made of titanium that can be used repeatedly, uniform electrodeposition is difficult to obtain compared to a copper cathode. However, on the titanium cathode, using a sulfuric acid bath having a copper composition of 40 to 60 g / L and sulfuric acid of 150 to 200 g / L, a copper plating is applied by energizing at a current density of 250 A / m ² for about 1 hour. It was confirmed that the occurrence of uneven electrodeposition can be prevented when the sample is used for electrowinning a chloride bath.

  Here, the surface roughness of the copper cathode is not particularly limited, but is preferably 5 to 20 μm in terms of a 5-point standard roughness (Rz). That is, when the surface roughness is within this range, the smoothness of the electrodeposit is improved and the influence of the surface state of the initial cathode is small.

  The width of the cathode is not particularly limited, but is preferably increased at a rate of 10 to 30% with respect to the width of the anode used in the electrolytic cell. This further prevents needle-like crystals that are likely to occur at the cathode end. That is, when the width of the cathode is less than 10% of the width of the anode, the effect of preventing acicular crystals at the cathode end is small. On the other hand, when the width of the cathode exceeds 30% with respect to the width of the anode, the generation of acicular crystals can be prevented, but the electrodeposition at the end is insufficient, and the electrodeposit is too thin.

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples of the present invention, but the present invention is not limited to these examples. The metal used in Examples and Comparative Examples was analyzed by ICP emission analysis, and the concentration of glue or gelatin was determined from the amount of additive.
Moreover, the electrolytic cell used by the Example and the comparative example is as follows.

[Electrolysis tank]
The shape was a box shape having a length of 60 mm, a width of 90 mm, and a depth of 160 mm, and was made of vinyl chloride. Here, a partition made of Tetoron filter cloth was provided in the electrolytic cell at a position of 20 mm on the anode side and 40 mm on the cathode side in the length direction of the electrolytic cell. Moreover, the drainage port was attached to the position which becomes 15 mm from the electrolytic cell upper part. The anode used was a chlorine-generating insoluble anode manufactured by Permerek Electrode Co., Ltd., masked with tape so that the electrode area was 65 × 120 mm. As the cathode, a copper seed plate having a thickness of 0.7 mm was used so that the electrode area was the same as that of the anode. They were charged and fixed in the electrolytic cell so that the distance between the electrodes was 60 mm. The back surfaces of both electrodes were masked on the entire surface.

(Examples 1 to 3, Comparative Example 1)
Using the electrolytic cell, pulse electrolysis (Examples 1 to 3) and continuous electrolysis (Comparative Example 1) were performed, and the obtained electrodeposition states were compared.
Here, as the electrolytic solution to be supplied to the cathode, first grade cuprous chloride and sodium chloride are dissolved in pure water so that the copper concentration is 60 g / L and the chloride concentration is 100 g / L. A solution adjusted with hydrochloric acid so that the pH is 1 was used. The additive was not added. The liquid supply temperature of the electrolytic solution was 60 ° C.
The energization was performed at a current of 2.34 A at a current density of 300 A / m ² . During this time, in pulse electrolysis (Examples 1 to 3), a current amount of 28 AH corresponding to the case of energizing for 12 hours with normal continuous energization while performing intermittent (pulse) energization that repeats energization and power failure at a constant cycle is reached. Electrolysis was performed until time. Here, as a pattern of intermittent energization, an effective energization rate 83% (Example 1) consisting of energization 150 seconds / cycle and a power failure 30 seconds / cycle, an effective energization rate consisting of energization 45 seconds / cycle and a power failure 30 seconds / cycle. An effective energization rate of 50% (Example 3) consisting of 60% (Example 2) and energization 30 seconds / cycle and power failure 30 seconds / cycle was used. The effective energization rate is calculated by energization time / (energization + power failure time) × 100%. Moreover, each energization time at this time was 15, 20, and 24 hours. In continuous electrolysis (Comparative Example 1), the effective energization rate was 100%, and energization was performed for 12 hours.

  After the completion of electrolysis, the surface state of the obtained electrodeposit on the cathode was observed. As a result, in the case of pulse electrolysis (Examples 1 to 3), the needle-like shape on the outer periphery of the cathode was compared with continuous electrolysis (Comparative Example 1). It was found that the occurrence of electrodeposition was suppressed and the smoothness of the central part was improved. An example of the results is shown in FIG. 4 (Comparative Example 1), FIG. 5 (Example 1) and FIG. 6 (Example 2). 4, 5 and 6 are photographs showing the surface state of the obtained cathode electrodeposit. 5 and 6, it can be seen that the intermittent electrode energization is clearly suppressed and the smoothness of the central portion is improved by intermittent energization as compared with FIG. In FIG. 4, a large number of needle electrodepositions occur around the cathode, and unevenness due to grains is conspicuous in the center.

Moreover, the electrodeposit is observed with a microscope, the size of the electrodeposited crystal is read, and the result of conversion into the size of the crystal grain is shown in FIG. FIG. 7 shows the relationship between the effective energization rate and the crystal grain size (mm ³ ). From FIG. 7, it can be seen that the crystal grains are smaller, that is, smoothed as the effective current ratio decreases.

Example 4
The same procedure as in Example 3 was carried out except that an electrolytic solution to which industrial glue (weight average molecular weight (Mw): 36053) was added at a concentration of 1 g / L was used. When the surface state was observed, in appearance, the pulse electrolysis of the electrolyte added with glue suppresses the occurrence of needle-like electrodeposition on the outer periphery of the cathode and improves the smoothness of the central portion compared to continuous electrolysis. I understood that. The results are shown in FIG. FIG. 8 is a photograph showing the surface state of the obtained electrodeposit on the cathode. From FIG. 8, compared with FIG. 4 (Comparative Example 1), the occurrence of acicular electrodeposition on the outer periphery of the cathode is clearly suppressed and the smoothness of the central part is improved by the intermittent energization and the addition of glue. I understand.

(Example 5)
The same procedure as in Example 1 was carried out except that the cathode size was increased by 10% from the anode, the width was 75 mm × the length was 90 mm, and the chloride concentration of the electrolyte was adjusted to 200 g / L. After the electrolysis, the surface state of the obtained electrodeposit on the cathode was observed, and it was found that the occurrence of needle electrodeposition on the outer periphery of the cathode was suppressed by intermittent energization and the enlargement of the cathode area. The results are shown in FIG. FIG. 9 is a photograph showing the surface state of the obtained electrodeposit on the cathode. From FIG. 9, it can be seen that the occurrence of needle electrodeposition on the outer periphery of the cathode is suppressed by intermittent energization and enlargement of the cathode area.

(Example 6)
The cathode dimensions were increased by 10% from the anode, and the width 75 mm × length 90 mm were used, the chloride concentration of the electrolyte was adjusted to 200 g / L, and gelatin (weight average molecular weight as an additive) (Mw): 39166) was used in the same manner as in Example 1 except that an electrolytic solution added at a concentration of 1 g / L was used. After completion of electrolysis, the surface state of the obtained electrodeposit on the cathode was observed. It has been found that the occurrence of needle electrodeposition on the outer periphery of the cathode is suppressed and the smoothness of the central portion is improved by energization, addition of gelatin, and enlargement of the cathode area. The results are shown in FIG. FIG. 10 is a photograph showing the surface state of the obtained electrodeposit on the cathode. From FIG. 10, it can be seen that the intermittent energization, the addition of gelatin, and the enlargement of the cathode area suppress the occurrence of needle-like electrodeposition on the outer periphery of the cathode and further improve the smoothness of the central portion.

  As is clear from the above, in Examples 1 to 6, since intermittent energization was performed at a predetermined effective energization rate, it can be seen that an electrodeposit excellent in smoothness can be obtained compared to continuous energization (Comparative Example 1). .

  As is clear from the above, the copper electrolysis method in the acidic chloride bath of the present invention efficiently and safely produces a cathode with excellent smoothness, particularly in the copper electrowinning method used in the field of wet copper smelting. It is suitable as a method.

It is a figure which shows the relationship between the surface roughness of a cathode, and an electric current density at the time of using the electrolytic solution of additive-free industrial glue and an electrolyte concentration of 1 g / L. It is a figure which shows the relationship between the surface roughness of a cathode, and an electric current density at the time of using no electrolyte for industrial use, and using electrolyte solution with a nickel concentration of 1, 0.1, and 0.01 g / L. It is a figure which shows the relationship between the surface roughness of a cathode, and current density at the time of using the electrolyte solution which contains gelatin, glue, and rough glue at the density | concentration of 1 g / L without industrial glue. It is the photograph showing the surface state of the electrodeposit of the cathode obtained by electrolysis. (Comparative Example 1) It is the photograph showing the surface state of the electrodeposit of the cathode obtained by electrolysis. Example 1 It is the photograph showing the surface state of the electrodeposit of the cathode obtained by electrolysis. (Example 2) It is a figure showing the relationship between an effective electricity supply rate and the magnitude | size (mm < ³ >) of a crystal grain. It is the photograph showing the surface state of the electrodeposit of the cathode obtained by electrolysis. Example 4 It is the photograph showing the surface state of the electrodeposit of the cathode obtained by electrolysis. (Example 5) It is the photograph showing the surface state of the electrodeposit of the cathode obtained by electrolysis. (Example 6)

Claims (8)

A copper electrolysis method for obtaining an electrodeposit excellent in smoothness from an electrolytic solution comprising an acidic chloride bath containing copper,
The electrolytic solution was supplied to an electrolytic cell equipped with a cathode and an anode, and energization of the electrolytic cell was made intermittent, and the energization time was divided by the total time of the energization time and power outage time in one cycle. A copper electrolysis method characterized in that an effective energization rate is 50 to 90%.   The copper electrolysis method according to claim 1, wherein a power failure time used for the intermittent energization is 30 seconds to 1 minute.   3. The copper electrolysis method according to claim 1, wherein the electrolytic solution is an acidic copper chloride aqueous solution (A) having a copper concentration of 40 g / L or more and a solubility limit or less.   The electrolytic solution is an acidic chloride containing nickel or gelatin having a copper concentration of 40 g / L or more and a solubility limit or less and a weight average molecular weight (Mw) of 40,000 or less at a concentration of 0.1 to 1 g / L. It is a copper aqueous solution (B), The copper electrolysis method of Claim 1 or 2 characterized by the above-mentioned.   The said electrolytic cell is comprised from the cathode chamber and anode chamber which were partitioned off with the filter cloth-made diaphragm, The copper electrolysis method in any one of Claims 1-4 characterized by the above-mentioned.   6. The copper electrolysis according to claim 5, wherein the supply liquid to the anode chamber is an acidic copper chloride aqueous solution (A), while the supply liquid to the cathode chamber is an acidic copper chloride aqueous solution (B). Method.   The material of the said cathode is copper, and the surface roughness is 5-20 micrometers in the value represented by 5-point standard roughness (Rz), The copper electrolysis of Claims 1-6 characterized by the above-mentioned. Method.   The copper electrolysis method according to claim 1, wherein the width of the cathode is increased at a rate of 10 to 30% with respect to the width of the anode.

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