JP6045481B2 - Method for producing electrolytic copper - Google Patents

Description

  The present invention relates to a method for producing electrolytic copper, and more particularly, to a method for producing electrolytic copper that can achieve both smoothness of electrolytic copper and suppression of an increase in S quality in electrolytic copper.

  The main component of the electrolytic solution used for electrolytic purification of copper is a copper sulfate solution, but a small amount of organic or inorganic substances are added as additives. The additive is used for improving the deposited state of copper in the cathode plate. As organic additives, additives that form protective colloids such as glue, gelatin, and lignin (pulp waste liquor) and organic substances having a functional group such as thiourea and aloin are commonly used. In general, the activation polarization at the time of deposition is increased by the additive, and the uniform electrodeposition is improved by increasing the polarization, so that the deposited metal can be dense and have a uniform surface. Since such additives are gradually consumed as electrolysis continues, it is necessary to add them from time to time.

  In recent years, further improvement in production efficiency has been demanded, and in order to improve production efficiency, it is necessary to perform electrolysis at a high current density. In order to maintain smoothness, it is necessary to add more thiourea. However, if thiourea is added excessively, the quality of S (sulfur) in the electrolytic copper is increased, and there is a possibility that the electrolytic copper product standard (15 ppm or less) is exceeded. Therefore, for example, Patent Document 1 proposes a method of obtaining good surface electrolytic copper by increasing both the chlorine ion addition amount and the thiourea addition amount. Moreover, in patent document 2, it replaces with maintaining the liquid temperature of electrolyte solution at 63-65 degreeC, or increasing the quantity of the thiourea in electrolyte solution, and increases chloride ion concentration within the range of 60 mg / L or less. Thus, a method for producing electrolytic copper having a smooth surface and low S quality has been proposed.

Here, although the action of thiourea and chloride ions is not necessarily clear, it is considered as shown in FIG. FIG. 12 is a molecular structure diagram of thiourea, and FIG. 13 is an image diagram of the adsorbed state of the additive on the cathode surface. That is, thiourea forms a complex ([Cu (TU)] ⁺ ) with copper ions (Cu ⁺ ), and is present somewhat higher near the surface of the cathode 50. On the other hand, Cl ⁻ ions in the electrolytic solution are specifically adsorbed on the cathode surface and are concentrated as compared with the bulk of the electrolytic solution. Both the complex ([Cu (TU)] ⁺ ) and Cl ⁻ ions are adsorbed on the cathode surface, but the increase of Cl ⁻ ions reduces S entrainment in thiourea, thereby smoothing the copper electrode. It is considered that the increase in the quality and S quality can be suppressed.

Japanese Patent Laid-Open No. 11-12777 Japanese Patent Laid-Open No. 9-24188

However, the current density shown in the Examples of Patent Document 1 is only 250A / m ^2, the chloride current density is shown in Patent Document 1 in operation at high current densities exceeding 300A / m ² ions It is not shown whether the concentration and thiourea concentration are appropriate.

  On the other hand, Patent Document 2 focuses on the temperature of the electrolytic solution and the chlorine ion concentration in the electrolytic solution in operation at a high current density, and instead of increasing thiourea, the chlorine ion concentration in the electrolytic solution. Although it is characterized by an increase within a range of 60 mg / L or less, the concentration ratio between the thiourea concentration and the chloride ion concentration appropriate for the smoothness of electrolytic copper and the suppression of the increase in S quality is not shown. Absent. Moreover, if the chlorine ion concentration in the electrolytic solution is increased, there is a concern about the problem of corrosion of the cathode plate and the electrolytic purification equipment. In this regard, paragraph number “0013” of Cited Document 1 observes pitting corrosion by immersing strips made of SUS316 for 2 months in an electrolytic solution having a chlorine ion concentration of 45 mg / L or more and 60 ° C. or higher. However, since no abnormality was observed, it has been shown that SUS316 may be used as a device material. However, it is practically difficult to construct all the members constituting the electrolytic purification equipment with such a material.

  Therefore, the present invention has been made in view of such problems, and even when electrolytic refining of copper is performed in a state where the current density is high, the surface smoothness is maintained appropriately, and the chloride ion concentration and the thiourea concentration are maintained. It is an object of the present invention to provide a method for producing electrolytic copper capable of preventing the thiourea from being entrained in the electrolytic copper and simultaneously suppressing the increase in S quality by maintaining the ratio at a predetermined ratio.

The invention according to claim 1 to solve the above described problems is the electrolytic copper manufacturing method by electrolytic purification with chloride ion and thiourea as an additive, drainage tank withdrawn from the electrolytic cell at a constant flow rate Measuring the concentration of thiourea and chloride ions in the electrolytic solution recovered to a predetermined time, and calculating a concentration ratio of the chloride ion concentration and the thiourea based on the measurement results; the drainage range concentrations of thiourea the thiourea concentration of a predetermined electrolyte in the vicinity of the liquid supply portion of the electrolytic cell so as not to fall below a predetermined concentration of the recovered electrolyte into the tank from the electrolytic cell In order to maintain a constant amount of thiourea supplied to the dissolution tank based on the measurement result, thereby supplying a new electrolyte solution for replenishment quantitatively to the supply tank. Thiourea And performing density adjustment, the supply concentration ratio between the concentration and the chloride ion concentration of thiourea of the drainage electrolytic solution recovered to tank from the electrolytic cell to the supply tank to be within a predetermined range Adjusting the concentration of hydrochloric acid, which is a chloride ion source for supplying, supplying thiourea and chloride ions adjusted in concentration to the supply tank, the thiourea stored in the supply tank, and the A step of continuously supplying an electrolytic solution containing chloride ions into the electrolytic cell at a constant flow rate .

The present invention according to claim 2 in order to solve the above described problems is the electrolytic copper method according to claim 1, the concentration of thiourea in the effluent electrolyte solution recovered to tank from the electrolytic bath The concentration of the thiourea in the electrolyte solution in the vicinity of the liquid supply part of the electrolytic cell is maintained within the range of 5.0 to 6.0 ppm so that the concentration does not fall below 2.0 ppm, and is recovered in the drainage tank. The concentration ratio obtained by dividing the concentration (ppm) of thiourea in the electrolyte by the chloride ion concentration (mg / L) is in the range of 0.04 to 0.07, preferably in the range of 0.04 to 0.06. Thus, the thiourea and the chloride ions are continuously supplied into the electrolytic cell through the supply tank .

In order to solve the above problems, the present invention according to claim 3 is the method for producing electrolytic copper according to claim 1 or 2, wherein the current density in electrolytic refining is in the range of 300 to 320 A / m ^2. Features.

  According to the method for producing electrolytic copper according to the present invention, thiourea can be optimally added without excessively added, and the chloride ion concentration relative to the thiourea concentration in the electrolytic solution can be maintained within an optimal range. Therefore, there is an effect that it is possible to achieve both the smoothness of the electrolytic copper and the suppression of the increase in the S quality while preventing the S component in the thiourea from being caught in the electrolytic copper and the generation of the bumps.

It is a block diagram which shows one Embodiment of the electrolytic purification equipment for enforcing the manufacturing method of the electrolytic copper which concerns on this invention. It is a front view which shows a feeder apparatus. It is a front view which shows the detail of the screw of a feeder apparatus. It is a front view which shows the detail of the hopper part of a feeder apparatus. It is explanatory drawing which shows the motion of a throwing chute. It is side surface sectional drawing which shows the structure of a hopper. It is a flowchart which shows one Embodiment of the addition amount adjustment of thiourea. It is a flowchart which shows one Embodiment of the addition amount adjustment of hydrochloric acid. The various characteristics of the thiourea in Example 1 are shown, (a) is a thiourea concentration characteristic diagram in the electrolyte solution on the supply side, (b) is a thiourea concentration characteristic diagram in the electrolyte solution on the drain side, (c) ) Is a characteristic graph of concentration ratio transition of thiourea / chloride ions in the electrolyte solution on the drain side. (A) is a current efficiency transition characteristic diagram, (b) is an electrolytic copper S (sulfur) concentration transition characteristic chart, and (c) is a liquid temperature transition characteristic of the electrolytic solution. The various characteristics of thiourea in Example 2 are shown, (a) is a thiourea concentration characteristic diagram in the electrolyte solution on the drain side, and (b) is the thiourea / chloride ion concentration in the electrolyte solution on the drain side. Ratio transition characteristic diagram, (c) is an electrolytic copper S (sulfur) concentration transition characteristic diagram. It is a molecular structure diagram of thiourea. It is an image figure of the adsorption state of the additive in a cathode surface.

[Configuration of electrolytic purification equipment]
Hereinafter, a preferred embodiment of a method for producing electrolytic copper according to the present invention will be described with reference to the drawings. First, an electrolytic purification facility for carrying out the method for producing electrolytic copper according to the present invention will be described. FIG. 1 is a block diagram showing an embodiment of an electrolytic purification facility for carrying out the electrolytic copper production method according to the present invention.

  The illustrated electrolytic purification equipment 1 generally includes an electrolytic tank 11 filled with an electrolytic solution 10, a drain tank 12 for quantitatively collecting the electrolytic solution 10 from the electrolytic tank 11, and a new electrolytic solution for supplementation. Supply tank 13 for quantitatively supplying 10 to the electrolytic cell 11, hydrochloric acid tank 14 for storing hydrochloric acid 140 as one of the additives, and electrolysis for storing fresh electrolytic solution 10 for supplying to the supply tank 13 In addition to the liquid supply tank 15, the apparatus further includes an additive dissolution apparatus 2 that continuously dissolves additives such as thiourea and glue, and an additive solution supply apparatus 3 that supplies the additive solution 200 to the supply tank 13. It is configured. In addition, a pump 17a is provided in the middle of a pipe 16a for transferring the electrolytic solution 10 collected in the drain tank 12 to the supply tank 13, and a pipe for transferring the hydrochloric acid 140 stored in the hydrochloric acid tank 14 to the supply tank 13. A pump 17b is provided in the middle of 16b, and a pump 17c is provided in the middle of the pipe 16c for transferring the fresh electrolyte 10 stored in the electrolyte supply tank 15 to the supply tank 13. A pump 17d is disposed in the pipe 16d for transferring the electrolytic solution 10 to which the additive stored in the tank is added to the electrolytic cell 11. In addition, a filtration device 18 is provided in the pipe 16 a, and after removing floating substances from the electrolytic solution 10 collected in the drainage tank 12 by the filtration device 18, the electrolytic solution 10 is returned to the supply tank 13. The circulation use of the electrolytic solution 10 is intended.

  In the electrolytic cell 11, a plurality of anodes (not shown) formed by casting crude copper serving as an anode, and a plurality of cathode plates 5 for growing copper by electrodepositing copper on the electrodeposition surface. Are alternately immersed at a predetermined interval. In addition, the electrolytic solution 10 is supplied to the electrolytic cell 11 via a supply tank 13. The electrolytic solution 10 is supplied from a supply port (not shown) provided on the lower side of one end portion in the longitudinal direction of the electrolytic cell 11 and is collected from the upper side of the opposite end portion. As the cathode plate 5, a stainless steel plate is used for electrolysis purification by the permanent cathode method (PC method). The additive dissolving device 2 continuously dissolves the additive used in the electrolytic purification, and the additive solution 200 dissolved by the additive dissolving device 2 is put into the supply tank 13 by the additive solution supplying device 3. It is continuously supplied into the stored electrolyte 10.

[Configuration of additive dissolution apparatus]
The additive dissolution apparatus 2 includes a dissolution tank 23 for dissolving the additive and a first feeder device 22a that is an additive supply apparatus for continuously adding the additive to the dissolution tank 23. Dissolution apparatus 20a, a second dissolution apparatus 20b including a second feeder apparatus 22b which is an additive supply apparatus for continuously adding other additives to the dissolution tank 23, and a solvent in the dissolution tank 23. A solvent supply device 50 constituted by a valve 50a and a pipe 50b, a liquid level measuring device 27 for measuring a change in height of the liquid level of the additive solution 200 stored in the dissolution tank 23, The electronic thermometer 28 for measuring the temperature of the additive solution 200 in the dissolution tank 23 is provided. The operations of the first feeder device 22a, the second feeder device 22b, and the solvent supply device 50 are controlled by the control device 30. Further, a pump 25 is provided in the pipe 24 for transferring the additive solution 200 adjusted in the dissolution tank 23 to the supply tank 13. In FIG. 1, the pipes 16 b and 24 are connected to the supply tank 13 in a connected state. However, the pipes 16 b and 24 are not limited to this, and may separately reach the supply tank 13 independently. In addition, the solvent in this embodiment is water.

  In the present embodiment, two types of additives, thiourea 60a and glue 60b, are used as additives, and these additives are dissolved and mixed in one dissolution tank 23. Therefore, the additive dissolution apparatus 2 is the first dissolution apparatus. Two systems, 20a and a second dissolving device 20b, are provided. As described above, the additive supply device 2 may be provided in a necessary number according to the type of additive to be added to the electrolytic solution 10 or a mixture of a plurality of additives in a predetermined ratio in advance. It can also be set as the structure which provides only one by using.

  The upper surface of the dissolution tank 23 is hermetically sealed by an upper surface plate 23b, and an axial fan 23c is attached to the upper surface plate 23b. By exhausting the air in the space in the dissolution tank 23 to the outside by the axial fan 23c, the steam generated inside the dissolution tank 23 is discharged to the outside, and the pressure inside the dissolution tank 23 is set to a charging chute 220a, which will be described later. The pressure is relatively lower than the pressure in the first feeder device 22a and the second feeder device 22b communicated through 220b. By forming in this way, it is prevented that the vapor | steam generate | occur | produced in the melting tank 23 reaches the 1st feeder apparatus 22a and the 2nd feeder apparatus 22b, and moisture is absorbed and solidified or deteriorated. In particular, since the thiourea 60a has high hygroscopicity, such a configuration makes it possible to prevent solidification and dissolve smoothly.

  In addition, a pipe 23a for passing steam is disposed around the dissolution tank 23, and the additive solution 200 stored in the dissolution tank 23 is kept at a predetermined temperature, for example, 50 ° C. by heat exchange. Be able to. In addition, it is good also as a structure which heat-reserves an additive solution by distribute | circulating warm water through the piping 23a, and it is also possible to cool the additive solution 200 by distribute | circulating cold water.

[Configuration of additive supply device]
The 1st feeder apparatus 22a and the 2nd feeder apparatus 22b which supply an additive to the dissolution tank 23 are comprised using "CE-W" type | mold "biaxial screw type cassette weighting feeder" by Kubota Corporation, for example. can do. Here, since the 1st feeder apparatus 22a and the 2nd feeder apparatus 22b are provided with the substantially same structure, the structure is demonstrated below based on the 1st feeder apparatus 22a. The first feeder device 22a is also referred to as a loss infeeder. As schematically shown in FIG. 2, the base 221; a drive unit 222 installed on the base 221; The screw mechanism 223 that is rotationally driven, the hopper portion 224 that is disposed above the screw mechanism 223 and supplies the additive to the screw mechanism 223, and the additive that has been fed to the end of the screw mechanism 223 is discharged. A discharge cylinder 235 and a load cell 26a for measuring the amount of the discharged additive are provided. The discharge tube 235 is connected to a charging chute 220 a that serves as an additive supply path to the dissolution tank 23.

  FIG. 3 is a front view showing details of the screw of the feeder device. As shown in FIG. 3, the screw mechanism 223 includes screws 225a and 225b having spiral screw blades 226 provided on the outer periphery thereof, and these can be rotated by the driving unit 222 in a state where they are arranged in parallel. It is stored. The screw blades 226 of the screws 225a and 225b are installed with a slight gap so as not to contact each other. As a result, a necessary amount of additive is continuously cut out and supplied into the dissolution tank 23.

  FIG. 4 is an exploded view showing details of the hopper 224. As shown in FIG. 4, the hopper portion 224 is installed in the upper portion of the screw mechanism 223 and has a bowl-shaped supply hopper 227 having a supply port for supplying an additive to the screw mechanism 223 at the lower portion, and the supply hopper 227. The agitator 228 is disposed in a state where it is supported by the shafts 227a and 227b, and is agitated to prevent the additive from solidifying by being driven to rotate by the driving unit 222, and the upper surface of the supply hopper 227. Gasket 229, clamp 230 installed on the upper surface of gasket 229, weighing hopper 231 installed on the upper surface of clamp 230, gasket 232 installed on the upper surface of weighing hopper 231, and installed on the upper surface of gasket 232 It comprises a clamp 233 and a lid 234 installed on the upper surface of the clamp 233. There. The additive, particularly thiourea 60a, is highly hygroscopic and easily solidified, so that it is stirred by the agitator 228 so as not to agglomerate.

  The charging chute 220a for guiding the additive to the dissolution tank 23 is formed with an inclined portion inclined obliquely from the middle, and a pipe 50b of the solvent supply device 50 is provided at a predetermined position on the discharge tube 235 side of the charging chute 220a. Are connected to each other to form a solvent introduction part 50d. When the additive is introduced into the dissolution tank 23 via the introduction chute 220a, the dissolution tank 23 is dissolved while the additive is dissolved by supplying a part of water as a solvent to be supplied to the dissolution tank 23 from the solvent introduction part 50d. Can be thrown into. Thus, the additive is smoothly and reliably dissolved without the additive being attached to the inner wall of the charging chute 220a.

  Further, as shown in FIG. 5, the charging chute 220 a can be rotated in the horizontal direction, and by providing a spare dissolution tank 29 separately from the dissolution tank 23, the two dissolution tanks 23 and 29 can be provided. It can be changed and used as appropriate. By providing the two dissolution tanks 23 and 29, when performing the maintenance of the dissolution tank 23, residue cleaning, or the like, continuous operation is possible without stopping the operation by using the other dissolution tank 29. In the present embodiment, the number of dissolution tanks is two, but the number is not limited to this, and three or more tanks may be provided. Further, in this embodiment, the throwing chute 220a is manually rotated, but it may be configured to automatically rotate by electric means or the like.

  The load cell 26a measures the weight of 10 members from the supply hopper 227 to the lid 234 and the additive contained in the hopper unit 224. That is, if the total weight Wh of 10 members from the supply hopper 227 to the lid 234 is measured in advance and the total weight Wt associated with the storage of the additive is measured with respect to this weight Wh, (Wt−Wh = By calculating Wn), the weight Wn of the additive in the hopper 224 can be measured.

  Further, the first dissolving device 20a and the second dissolving device 20b store additives for replenishing the additive that has been cut out from the first feeder device 22a and the second feeder device 22b, respectively. Hoppers 21a and 21b are provided. As shown in FIG. 6, the hoppers 21 a and 21 b include a main body 211 a that stores the additive, a crusher 211 b that is provided inside the main body 211 a, a motor 211 d that drives the crusher 211 b, and a first additive. The screw conveyor 211c is provided to be transferred to the feeder device 22a. Since the additive thiourea 60a is highly hygroscopic and easily hardened, the agglomerated additive is pulverized by the crusher 211b before being transferred to the first feeder device 22a and then transferred by the screw conveyor 211c. It has become. The addition of the additive to the hoppers 21a and 21b is performed by opening the upper surface cover 211e provided at the upper portion and introducing the additive contained in a flexible container (not shown) from the opening.

[Configuration of additive solution supply apparatus]
The additive solution supply device 3 is a device that continuously supplies the additive solution 200 dissolved by the additive dissolving device 2 and the hydrochloric acid 140 in the hydrochloric acid tank 14 into the electrolytic solution 10 through the supply tank 13. The additive dissolving device 2 includes a pump 25 that transfers the additive solution 200 from the dissolving tank 23 to the supply tank 13 and a control device 30 that controls the pump 25. The control device 30 also controls the first feeder device 22 a and the second feeder device 22 b and the pump 17 b that transfers the hydrochloric acid 140 to the supply tank 13. The control device 30 includes at least a central processing unit and a storage device (both not shown), and various measurement data and measurement data sent to the control device 30 based on a program stored in the storage device in advance. Various controls are executed by processing in the central processing unit using.

  The supply of the electrolytic solution 10 from the supply tank 13 into the electrolytic cell 11 is performed by continuously supplying the electrolytic solution 10 stored in the supply tank 13 into the electrolytic cell 11 at a constant flow rate. The electrolyte 10 is a fresh electrolyte 10 stored in the electrolyte supply tank 15, and the electrolyte is extracted from the electrolyte tank 10 at a constant flow rate and collected in the drainage tank 12, and the suspended matter is removed by the filtration device 18. Liquid 10, additive solution 200 dissolved in dissolution tank 23, and hydrochloric acid 140 stored in hydrochloric acid tank 14 are mixed and stored as electrolyte 10 for supply. As described above, the electrolytic solution 10 collected in the drainage tank 12 is circulated after the suspended matter is removed by the filtration device 18. Since the suspended matter adheres to the surface of the cathode plate 5 and causes the formation of bumps, the smoothness of the electrolytic copper is ensured by removing this in advance. Then, the control device 30 controls the pump 25 so as to transfer the additive solution 200 adjusted in the dissolution tank 23 into the supply tank 13 at a predetermined flow rate. In the present embodiment, the control device is configured so that the flow rate of the electrolytic solution 10 supplied from the supply tank 13 to the electrolytic cell 11 and the flow rate of the electrolytic solution 10 collected from the electrolytic cell 11 to the drainage tank 12 are substantially the same. 30 is controlled. Here, conventionally, the additive is configured to be added to the drainage tank 12, and the electrolytic solution 10 to which the additive has been added is filtered by the filtration device 18. If there is, the loss of the additive becomes large, and thiourea and chloride ions added as additives are lost irregularly in the filtration device 18, so that the concentration ratio of the two at the time of supply to the electrolytic cell 11 is increased. Since it becomes difficult to adjust to a predetermined range, in this embodiment, the supply route to the supply tank 13 of the additive solution 200 and the supply route to the supply tank 13 of the electrolytic solution 10 collected in the drainage tank 12 It was decided to divide. As a result, the additive solution 200 does not pass through the filtration device 18, and therefore no loss occurs.

  On the other hand, the electrolyte solution 10 is added with hydrochloric acid 140 as a chloride ion source for suppressing an increase in the S grade of electrolytic copper and improving smoothness. The hydrochloric acid 140 is adjusted to a predetermined concentration and stored in the hydrochloric acid tank 14, and the control device 30 of the additive dissolving device 2 controls the pump 17b to the supply tank 13 through the pipe 16b at a constant flow rate. It comes to supply. The concentration of chloride ions in the electrolytic solution 10 is adjusted by changing the concentration of hydrochloric acid 140 in the hydrochloric acid tank 14. That is, the chloride ion concentration in the electrolytic solution 10 sampled from the drainage tank 12 at regular intervals is measured, and the control device 30 uses the measurement result to determine the chloride necessary for the concentration of hydrochloric acid 140 to be supplied. The amount of ions or the amount of water is calculated and added to the hydrochloric acid tank 14. The supply flow rate of hydrochloric acid 140 as a chloride ion source supplied from the hydrochloric acid tank 14 to the supply tank 13 is constant, and the concentration of chloride ions in the electrolytic solution 10 is adjusted by changing the concentration of the supplied hydrochloric acid 140. Do. The hydrochloric acid 140 may be supplied to the drainage tank 12 instead of the supply tank 13.

[Outline of the method for producing electrolytic copper according to the present invention]
Next, an outline of the method for producing electrolytic copper according to the present invention will be described. In the production of copper by electrolytic refining, the present inventors have electrodeposited when the concentration of thiourea 60a in the electrolytic solution 10 of the drainage tank 12 recovered from the electrolytic cell 11 is less than 2.0 ppm, based on the experience of operation so far. When an abnormal phenomenon occurs and the concentration of thiourea 60a in the electrolytic solution 10 increases, the concentration of sulfur (S) in the electrolytic copper increases, which causes a problem as a product. However, the electrolytic solution 10 is supplied from the supply tank 13 to the electrolytic cell 11. The concentration of thiourea 60a in the electrolytic solution 10 in the vicinity of the supply port for supplying the liquid is at least in the range of 5.0 to 6.0 ppm, and the concentration of thiourea 60a in the electrolytic solution 10 collected in the drainage tank 12 ( ppm) is less than 2.0 ppm, and the concentration ratio obtained by dividing the thiourea concentration (ppm) by the chloride ion concentration (mg / L) is in the range of 0.04 to 0.07, preferably 0.8. 04-0.06 If enclose with the sulfur in the copper (S) quality is maintained within specifications, also be produced good copper in operation in the range of 300~320A / m ² is a higher current density than conventional Confirm that you can. This point will be described later.

  Since thiourea 60a is consumed and reduced during electrolytic purification, in order to prevent the concentration of thiourea 60a in the electrolytic solution 10 of the drainage tank 12 from falling below 2.0 ppm, the electrolytic solution 10 in operation The concentration of thiourea 60a needs to be at least 2.0 ppm. Therefore, the concentration of thiourea 60a in the electrolytic solution 10 of the additive is used as an index, and the concentration of thiourea 60a in the electrolytic solution 10 in the drainage tank 12 is a predetermined set value, for example, an electrodeposition abnormality phenomenon occurs. Concentration ratio obtained by dividing the concentration (ppm) of thiourea 60a by the chloride ion concentration (mg / L) without falling below the lower limit of 2.0 ppm, which is likely to occur. In view of the fact that thiourea 60a is effectively consumed during electrolytic purification, electrolyte solution 10 is supplied from supply tank 13 to electrolytic cell 11 in the range of 07, preferably 0.04 to 0.06. The additive solution 200 from the dissolution tank 23 to the supply tank 13 by the additive solution supply device 3 so that the concentration of the thiourea 60a in the electrolyte solution 10 in the vicinity of the supply port to be supplied is in the range of 5.0 to 6.0 ppm. Supply and hydrochloric acid It is possible to obtain a proper electrolytic copper by performing the supply of hydrochloric acid 140 to the supply tank 14 to.

  Therefore, the electrolytic solution 10 in the vicinity of the supply port for supplying the electrolytic solution 10 from the supply tank 13 into the electrolytic cell 11 and the electrolytic solution 10 in the drainage tank 12 extracted from the electrolytic cell 11 are sampled at predetermined intervals. Then, the concentration of thiourea 60a in the electrolytic solution 10 is measured, and the control device 30 controls the operation of the first feeder device 22a of the first dissolving device 20a based on the measurement data, thereby adding the additive solution. The concentration of thiourea 60a in 200 is adjusted. In addition, for the electrolytic solution 10 sampled from the drainage tank 12, the concentration of chloride ions is also measured, and the concentration ratio between the concentration of thiourea 60a (ppm) and the concentration of chloride ions (mg / L) is calculated. Then, the concentration of hydrochloric acid 140 to be supplied to the supply tank 13 is adjusted. The concentration measurement of thiourea 60a and chloride ions in the electrolytic solution 10 sampled from the electrolytic bath 11 and the drain bath 12 is automatically performed every predetermined time, and the measurement data is input to the control device 30. Alternatively, the operator can measure the concentration at predetermined time intervals and input the measurement data to the control device 30. Here, in the present embodiment, the “electrolyte solution near the supply port” is provided with a supply port on the lower side of one end in the longitudinal direction of the electrolytic cell 11. It is.

  And when the density | concentration of the thiourea 60a in the electrolyte solution 10 sampled from the drainage tank 12 is less than 2.0 ppm which is a setting value, the control apparatus 30 of the screw mechanism 223 of the 1st feeder apparatus 22a. By increasing the operation speed, the supply amount of thiourea 60a supplied to the dissolution tank 23 is increased so that the concentration of thiourea 60a in the electrolyte in the drainage tank 12 does not fall below 2.0 ppm. Further, when the concentration of thiourea 60a in the electrolyte 10 sampled near the supply port exceeds 6.0 ppm which is the upper limit of the set value, the control device 30 causes the screw mechanism 223 of the first feeder device 22a. , And the amount of thiourea 60a supplied to the dissolution tank 23 is reduced so that the concentration of thiourea 60a in the electrolyte 10 near the supply port is within the range of 5.0 to 6.0 ppm. . On the other hand, when the concentration ratio obtained by dividing the concentration (ppm) of thiourea 60a in the electrolytic solution 10 sampled from the drain tank 12 by the chloride ion concentration (mg / L) is less than 0.04, hydrochloric acid 140 to be supplied is supplied. When the concentration ratio exceeds 0.07 or 0.06, the concentration is adjusted to increase the concentration of hydrochloric acid 140 to be supplied. When the concentration of thiourea 60a is within the range of the conditions, the control device 30 maintains the supply amount of the first feeder device 22a as it is. The supply amount of the thiourea 60 a to the dissolution tank 23 is measured by a load cell 26 a provided in the first feeder device 22 a, and the measurement data is sent to the control device 30. On the other hand, the necessary water for the amount of thiourea 60a to be added is controlled by controlling the opening and closing of the valve 50a of the solvent supply device 50 by the control device 30, and the amount of water supply is measured by a flow meter (not shown). The measurement data is sent to the control device 30. Therefore, the necessary amount of thiourea 60a can be calculated from the measurement data. On the other hand, when the change in the liquid level in the dissolution tank 23 is measured by the liquid level measuring device 27, and the liquid level of the additive solution 200 in the dissolution tank 23 is below a predetermined liquid level. In the case where the control device 30 operates the additive dissolving device 2 to create the additive solution 200, and the liquid level of the additive solution 200 in the dissolving tank 23 becomes equal to or higher than a predetermined liquid level. The control device 30 stops the operation of the additive dissolving device 2.

  Here, when the concentration is adjusted so as to increase the concentration of hydrochloric acid 140 to be supplied when the concentration ratio of the thiourea concentration and the chloride ion concentration exceeds 0.06, FIG. 9 and FIG. As shown in FIG. 10, it has been confirmed that the S grade of electrolytic copper can be stably suppressed to 8 ppm or less. Further, when the concentration is adjusted so as to increase the concentration of hydrochloric acid 140 supplied when the concentration ratio of the thiourea concentration and the chloride ion concentration exceeds 0.07, as shown in FIG. Furthermore, it has been confirmed that the S grade of electrolytic copper can be suppressed to 15 ppm or less, which is the standard for electrolytic copper products. That is, when the numerical value of the concentration ratio between the thiourea concentration and the chloride ion concentration is increased from 0.06 to 0.07, the chloride ion concentration is decreased accordingly. It is expected that the amount of copper involved in copper will increase, but if the numerical value of the concentration ratio of thiourea concentration and chloride ion concentration is in the range of 0.04 to 0.07, the S grade of the product will be reduced to electrolytic copper. It can be maintained within the product standard, and when it is in the range of 0.04 to 0.06, a higher quality product can be provided.

Next, a preferred embodiment of a method for producing electrolytic copper according to the present invention will be described in detail with reference to the drawings. FIG. 7 is a flowchart showing an embodiment of adjusting the addition amount of thiourea. First, the electrolytic bath 11 of the electrolytic purification equipment 1 is filled with the electrolytic solution 10, and a plurality of anodes (not shown) serving as anodes and cathode plates 5 are alternately arranged. The supply tank 13 is filled with additives such as thiourea 60a, glue 60b, and hydrochloric acid 140, which is a supply source of chloride ions, for improving the deposition state of copper in the cathode plate 5. 10 are stored. The thiourea 60a and glue 60b are dissolved in the dissolution tank 23, and the additive solution 200 is transferred to the supply tank 13 by the pump 25. The hydrochloric acid 140 is stored in the hydrochloric acid tank 14 and transferred to the supply tank 13 by the pump 17b. A predetermined number of cathode plates 5 are successively carried into the electrolytic cell 11 at a predetermined interval by a carry-in / carry-out system (not shown). Then, by applying a predetermined DC voltage between the anode and the cathode plate 5 in a range of current density of 300 to 320 A / m ² , for example, electrolytic refining of copper is performed, and electrolytic copper is applied to the surface of the cathode plate 5. Electrodeposit. When electrolytic copper is electrodeposited on the surface of the cathode plate 5 to a predetermined thickness, the cathode plate 5 is unloaded from the electrolytic cell 11 by the loading / unloading system and transferred to a predetermined location. Thereafter, a new cathode plate 5 is carried into the electrolytic cell 11 by the carry-in system, and the above-described electrolytic purification process is performed again.

  It is also possible to produce electrolytic copper by electrolyzing one anode as an anode twice (2 cycles). That is, the new anode and the cathode plate 5 are charged into the electrolytic cell 11 at the same time, and the new anode is not used up in the first cycle of the electrolytic purification process, but is used again in the next cycle. The first cycle is completed. After that, after the cathode plate 5 is lifted off and the electrolytic copper is peeled off, the new cathode plate 5 is again charged in the electrolytic cell 11 and electrolyzed in the second cycle. Furthermore, as another method, electrolytic copper can be produced by electrolyzing one anode serving as an anode in three times (three cycles). According to this method, since the operation of replacing the cathode plate 5 is performed in a state where the thickness of the electrolytic copper electrodeposited on the cathode plate 5 is thinner than that in the case of 1 or 2 cycles, the width between the anode and the cathode plate 5 is wide. Therefore, the possibility of short-circuiting due to non-uniform electrodeposition is low, and high current efficiency can be easily obtained. On the other hand, since it is necessary to replace the cathode plate 5 three times for one new anode, the work load increases.

  Each step shown in FIG. 7 is executed by a command from the control device 30. First, a predetermined amount of thiourea 60a as an additive is charged into the hopper portion 224 of the first feeder device 22a and a predetermined amount of glue 60b as another additive is charged into the hopper portion 224 of the second feeder device 22b. To do. When the additive is stored in each weighing hopper 231, the weighing (including the weight of the weighing hopper 231) of the additives (thiourea 60 a and glue 60 b) in each weighing hopper 231 is performed by the load cells 26 a and 26 b. The measured value S0 is sent to the control device 30. In the following description, the first feeder device 22a for introducing the thiourea 60a will be described, but the operation thereof is substantially the same as that for the second feeder device 22b for introducing the glue 60b.

  Next, the control device 30 operates the screw mechanism 223 provided in the hopper portion 224 of the first feeder device 22a to supply the additive thiourea 60a to the charging chute 220a at a predetermined flow rate. And the control apparatus 30 calculates the weight of the thiourea 60a supplied to the input chute | shoot 220a by measuring the weight of the thiourea 60a after supply, and comparing the measured value S1 and the previous measured value S0. . On the other hand, the control device 30 opens the valve 50 a of the solvent supply device 50 and starts supplying water as a solvent into the dissolution tank 23. At this time, a part of water is introduced into the solvent introduction part 50d through the pipe 50c branched from the pipe 50b of the solvent supply device 50, and the thiourea 60a is supplied to the dissolution tank 23 while being dissolved in water in the charging chute 220a. Is done. Thereby, an additive is adjusted (step S1). And the control apparatus 30 transfers the additive solution 200 created and adjusted in the dissolution tank 23 by operating the pump 25 to the supply tank 13 (step S2). The supply tank 13 stores the fresh electrolyte 10 supplied from the electrolyte supply tank 15 and the electrolyte 10 continuously recovered from the electrolyte tank 11 to the drain tank 12. The electrolyte solution 10 is recycled. Thus, the electrolytic solution 10 in the supply tank 13 to which the predetermined amount of additive is added is continuously supplied into the electrolytic cell 11 through the pump 17d. On the other hand, hydrochloric acid 140 as an additive from the hydrochloric acid tank 14 is supplied to the supply tank 13 separately from the additive solution 200 containing the thiourea 60a and the glue 60b. The supply process of the hydrochloric acid 140 will be described later.

  The electrolytic solution 10 in the drainage tank 12 extracted from the electrolytic cell 11 and the electrolytic solution 10 in the vicinity of the supply port of the electrolytic solution 10 supplied from the supply tank 13 into the electrolytic cell 11 are sampled every predetermined time ( Steps S3, 4), the concentration of thiourea 60a in the electrolyte is measured. Then, the measured concentration of thiourea 60a is compared with the set value (2.0 ppm, 5.0 to 6.0 ppm) (steps S5, 8, and 9), and the control device 30 is based on the measurement results. The amount of thiourea 60a supplied to the additive tank 23 is appropriately adjusted by controlling the operation of the first feeder device 22a of the first dissolving device 20a. Specifically, when the concentration of thiourea 60a in the electrolytic solution 10 sampled from the drainage tank 12 is lower than the set value of 2.0 ppm, the control device 30 controls the first feeder device 22a. When the speed of the screw mechanism 223 is increased to increase the supply amount of the thiourea 60a to the dissolution tank 23 (step S6), and the concentration of the thiourea 60a does not fall below the set value of 2.0 ppm, the control device 30 maintains the supply amount of the thiourea 60a to the dissolution tank 23 without changing the speed of the screw mechanism 223 of the first feeder device 22a (step S7). On the other hand, the control device 30 further compares the concentration of the thiourea 60a in the electrolytic solution 10 sampled near the supply port (step S4) with the set value. That is, when the measured value of the concentration of thiourea 60a in the electrolyte 10 sampled near the supply port exceeds 6.0 ppm which is the upper limit of the set value, the speed of the screw mechanism 223 of the first feeder device 22a is increased. The supply amount of the thiourea 60a to the dissolution tank 23 is reduced to be slow (step S10). On the other hand, when the concentration of thiourea 60a is not more than the preset value of 6.0 ppm, the control device 30 further determines whether or not the concentration is in the range of 5.0 to 6.0 ppm. If it is within the range of 0.0 to 6.0 ppm, the rotation speed of the screw mechanism 223 of the first feeder device 22a is maintained as it is and the supply and dissolution of the thiourea 60a is continued (step S7). When the measured value falls below 5.0 ppm, the control device 30 increases the speed of the screw mechanism 223 of the first feeder device 22a to increase the supply amount of the thiourea 60a to the dissolution tank 23 (step S6). ). In the case where the concentration of the thiourea 60a in the electrolyte solution 10 in the drainage tank 12 exceeds 2.0 ppm and the concentration of the thiourea 60a in the electrolyte solution 10 near the supply port is less than 5.0 ppm, The step of increasing the supply amount of thiourea 60a (step S6) may be prioritized.

  The supply amount of the thiourea 60a to the dissolution tank 23 is measured by a load cell 26a provided in the first feeder device 22a, and the measurement data is sent to the control device 30. On the other hand, the necessary water is supplied to the amount of thiourea 60a to be added by the control device 30 controlling the opening and closing of the valve 50a of the solvent supply device 50. Specifically, it is measured by a flow meter (not shown) provided in the solvent supply device 50. The concentration control of the additive can also be performed by adjusting the amount of solvent supplied.

  As described above, the control device 30 rotates the screws 225a and 225b of the screw mechanism 223 while appropriately controlling the rotation speed of the drive unit 222 of the first feeder device 22a, and the thiourea 60a discharge cylinder from the hopper unit 224. 235 is supplied to the dissolution tank 23 through the charging chute 220a. At this time, since the thiourea 60a is stirred by the agitator 228 in the supply hopper 227, solidification in the supply hopper 227 is prevented. Further, a part of water as a solvent supplied to the dissolution tank 23 is sent to the solvent introduction part 50d provided above the charging chute 220a via the pipe 50c, and the inside of the dissolution tank 23 is dissolved while dissolving the thiourea 60a. It is thrown into. Thus, by dissolving thiourea 60a with water quickly, dissolution is prevented from being inhibited by solidification due to moisture absorption. Further, the temperature of the additive solution is maintained at about 50 ° C. by circulating the steam through the pipe 23 a of the dissolution tank 23. Moreover, the additive cut out and reduced from the first feeder device 22a and the second feeder device 22b is sequentially replenished from the separately stored hoppers 21a and 21b. And since the hoppers 21a and 21b are equipped with the crusher 211b, even the additive which has high hygroscopicity and is easy to harden like the thiourea 60a can be smoothly supplied by appropriately crushing.

  Next, adjustment of the addition amount of hydrochloric acid 140 will be described. FIG. 8 is a flowchart showing an embodiment of adjusting the addition amount of hydrochloric acid. The electrolytic solution 10 in the drainage tank 12 is sampled every predetermined time (step S11), and the chloride ion concentration in the electrolytic solution 10 is measured (step S12). The sampling performed in step S3 can also be used for sampling (S11) from the drainage tank 12. Next, a ratio between the measured chloride ion concentration and the concentration of thiourea 60a measured in step S5 is calculated (step S13). If the concentration ratio obtained by dividing the concentration (ppm) of thiourea 60a by the chloride ion concentration (mg / L) is within the range of 0.04 to 0.07, the supply tank is maintained while maintaining the concentration of hydrochloric acid 140 as it is. 13 is continuously supplied (step S14). If the concentration ratio obtained by dividing the concentration (ppm) of thiourea 60a by the chloride ion concentration (mg / L) is not within the range of 0.04 to 0.07, the concentration ratio is further below 0.04. Or whether it exceeds 0.07 (step S15). When the concentration ratio exceeds 0.07, the concentration of hydrochloric acid 140 is increased (step S16), and when the concentration ratio is less than 0.04, the concentration of hydrochloric acid 140 is decreased (step S17). ). Thereby, the concentration ratio of thiourea 60a and chloride ions is maintained within the range of 0.04 to 0.07. As a result, the S grade of electrolytic copper can be suppressed to 15 ppm or less, which is the standard for electrolytic copper products. As described above, the S quality can be further improved to 8 ppm or less by maintaining the concentration ratio of thiourea 60a and chloride ions within the range of 0.04 to 0.06. is there. Note that each step shown in FIG. 8 may be executed in accordance with a command from the control device 30.

[Effect of the embodiment]
According to the method for producing electrolytic copper according to the present embodiment, thiourea is 5.0 to 6.0 ppm in the vicinity of the supply port of the electrolytic solution 20, and 2 in the electrolytic solution 20 collected in the drainage tank 12. 0.0 ppm and not exceeding thiourea and hydrochloric acid (chloride ion) in a certain ratio (range 0.04-0.07, preferably 0.04-0.06) By maintaining so as to be, there is an effect that it is possible to achieve both the smoothness of electrolytic copper and the suppression of the increase in S quality while preventing the thiourea-derived S from being entrained in the electrolytic copper and the occurrence of lumps.

  As described above, the preferred embodiment of the present invention has been described in detail. However, the present invention is not limited to the specific embodiment, and within the scope of the gist of the present invention described in the claims, Needless to say, various modifications and changes are possible.

Next, Example 1 will be described. The inventors manufactured electrolytic copper under the following conditions.
An electrolytic cell having a length of 1280 mm, a width of 5550 mm, and a depth of 1340 mm, 50 pieces of a crude copper anode having a length of 1060 mm, a width of 990 mm, and a thickness of 45 mm, and 49 pieces of cathode plates having a length of 1040 mm, a width of 1040 mm, and a thickness of 10 mm, respectively. They were arranged with an interval of 100 mm. Furthermore, the electrolytic solution has a copper concentration of 40 to 50 g / L and a sulfuric acid concentration of 165 to 180 g / L, and the electrolytic solution is supplied at a rate of 34 to 36 L / min. Carried out. In addition, electrolytic copper was manufactured by electrolyzing one crude copper anode twice. That is, a new crude copper anode and a cathode plate were simultaneously charged in the electrolytic cell, and the crude copper anode for electrodepositing the electrodeposited copper on the cathode plate was not completely used in one cycle of the electrolytic refining process. In the second cycle, after the completion of the first cycle, the cathode plate was lifted off and the copper electroplated off, and then the new cathode plate was charged again in the electrolytic cell in the second cycle for electrolysis. .

As a result, the results shown in FIGS. 9 and 10 were obtained. FIG. 9 shows various characteristics of thiourea in the examples, (a) is a thiourea concentration characteristic diagram in the electrolyte solution on the supply side, (b) is a thiourea concentration characteristic diagram in the electrolyte solution on the drain side, (C) is a concentration ratio transition characteristic diagram of thiourea / chloride ions in the electrolyte solution on the drain side. 10A is a current efficiency transition characteristic diagram, FIG. 10B is an electrolytic copper S (sulfur) concentration transition characteristic chart, and FIG. 10C is a liquid temperature transition characteristic chart of the electrolytic solution. As shown in FIGS. 9 (a) and 9 (b), the thiourea concentration on the liquid supply side of the electrolytic cell 22 is 5.0 to 6.0 ppm, and the concentration of thiourea in the electrolytic solution recovered in the drainage cell is set. When the concentration ratio of thiourea / chloride ion concentration was controlled to 0.04 to 0.06 as shown in FIG. 9 (c), it was 96 as shown in FIG. 10 (a). %, And it was confirmed that the S grade of electrolytic copper was stably suppressed to 8 ppm or less as shown in FIG. 10 (b). Furthermore, as shown to Fig.9 (a), even if a current density is a high current density of 300-311 A / m < ² >, it turns out that current efficiency is maintainable. And as shown in FIG.10 (c), even if the temperature of electrolyte solution is operated in the high temperature range of 64-67 degreeC (conventionally, for example, 64-65 degreeC), a current efficiency characteristic is above-mentioned high value ( It was also found that 96% or higher) can be maintained. As described above, according to this embodiment, even in the case of two-cycle manufacturing, current efficiency comparable to that in the case of three cycles can be obtained. In addition, since the burden of replacing the cathode plate is reduced compared to the case of 3 cycles, it is possible to reduce the workload while maintaining the current efficiency as in the case of 3 cycles.

Next, Example 2 will be described. In Example 2, electrolytic copper was produced under substantially the same conditions as in Example 1, but the concentration ratio of thiourea / chloride ion concentration was 0.04 to 0.00.
07 is managed. As a result, as shown in FIG. 11, it was confirmed that the S grade of electrolytic copper was stably suppressed to 15 ppm or less.

  As described above, the preferred embodiment of the present invention has been described in detail. However, the present invention is not limited to the specific embodiment, and within the scope of the gist of the present invention described in the claims, Needless to say, various modifications and changes are possible.

DESCRIPTION OF SYMBOLS 1 Electrolytic purification apparatus 2 Additive dissolution apparatus 3 Additive solution supply apparatus 5 Cathode plate 10 Electrolytic solution 11 Electrolytic tank 12 Drainage tank 13 Supply tank 14 Hydrochloric acid tank 15 Electrolytic solution supply tank 17b Pump 18 Filtration apparatus 20a First dissolution apparatus 20b 2nd dissolution apparatus 22a 1st feeder apparatus 22b 2nd feeder apparatus 23 Dissolution tank 24 Piping 25 Pump 26a, 26b Load cell 27 Liquid level measuring device 28 Electronic thermometer 30 Control apparatus 50 Solvent supply apparatus 14 Hydrochloric acid tank 140 hydrochloric acid

Claims (3)

In the method for producing electrolytic copper by electrolytic purification using chloride ions and thiourea as additives,
Measure the concentration of thiourea and chloride ions in the electrolytic solution withdrawn from the electrolytic cell at a constant flow rate and recovered into the drainage tank every predetermined time, and based on the measurement result, the chloride ion concentration and the Calculating a concentration ratio of thiourea;
Concentration predetermined range of the thiourea of the electrolytic solution of the vicinity of liquid supply unit of the electrolytic cell so that the concentration of thiourea of the drainage electrolytic solution recovered to tank from the electrolytic cell does not fall below a predetermined concentration In order to supply a supply tank for quantitatively supplying a new electrolyte for replenishment to the electrolytic cell by increasing / decreasing the supply amount of thiourea supplied to the dissolution cell based on the measurement result in order to maintain the inside Adjusting the concentration of thiourea,
Source of chloride ions for the concentration ratio of the concentration and the chloride ion concentration from the electrolytic cell thiourea of the drainage electrolytic solution recovered to the tank is supplied to the supply tank to be within a predetermined range Adjusting the concentration of hydrochloric acid,
Supplying concentration-adjusted thiourea and chloride ions to the supply tank;
Continuously supplying the electrolytic solution containing the thiourea and the chloride ions stored in the supply tank into the electrolytic cell at a constant flow rate;
A method for producing electrolytic copper , comprising : The method for producing electrolytic copper according to claim 1,
The concentration of the thiourea of the electrolyte in the vicinity of the liquid supply portion of said electrolytic cell so that the concentration of thiourea is not less than the 2.0ppm of the drainage electrolytic solution recovered to tank from the electrolytic cell 5.0 The concentration ratio obtained by dividing the concentration (ppm) of thiourea in the electrolytic solution recovered in the drainage tank by the chloride ion concentration (mg / L) is 0. The thiourea and the chloride ions are continuously supplied into the electrolytic cell through the supply tank so as to be in the range of 0.04 to 0.07, preferably in the range of 0.04 to 0.06. A method for producing electrolytic copper. In the manufacturing method of the electrolytic copper of Claim 1 or 2,
A method for producing electrolytic copper, characterized in that a current density in electrolytic purification is in the range of 300 to 320 A / m ² .

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