JP2009001874A - Permanent cathode system electrolytic refining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent cathode system electrolytic refining method by which the electrodeposition of metallic grains such as copper grains inside an insulating material attached to both side edges of a cathode plate is suppressed and the insulating material is easily detached. <P>SOLUTION: When the insulating material 5 is attached to both side edges of the cathode plate 4, after the cathode plate 4 is inserted and held in a cathode plate mounting groove 6 of the insulating material 5 which has a closed lower end, a silicone based caulking material 7 is injected from a gap between the lower end of the cathode plate 4 and the lower end closed part of the insulating material 5. In such a case, the silicone based caulking material 7 is filled only into a lower end portion of the gap between the cathode plate 4 and the cathode plate mounting groove 6 of the insulating material 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, in the electrolytic purification of the permanent cathode method, when electrolytically refining a metal such as copper using a cathode plate with an insulating material attached on both side edges, an electrolyte enters between the cathode plate and the insulating material, The present invention relates to a method for suppressing metal particles from adhering to a portion of a cathode plate covered with an insulating material.

  For example, in copper electrorefining of copper, electrolytic operation is performed by alternately charging a plurality of anode plates and cathode plates into an electrolytic cell. At that time, copper melts from the anode plate in which approximately 98% of the copper grade is cast, and the copper gradually electrodeposits on the cathode plate as the electrolysis progresses. Is obtained.

  In general copper electrolytic purification, a thin electric copper plate called a seed plate is used as a cathode plate. For example, as shown in FIG. 1A, a seed plate 1 made of electrolytic copper serving as a cathode plate has a handle 2 attached to an upper portion thereof, and a cathode beam 3 made of a conductive material held by the handle 2. Is suspended in the electrolytic cell. The seed plate 1 on which electrolytic copper is electrodeposited by electrolytic purification is washed after completion of electrolytic purification, the cathode beam 3 is extracted, and stored as it is in a storage place.

  In the seed plate electrolysis step, which is a separate step, the above-mentioned seed plate is electrodeposited with copper on a plate such as stainless steel called a mother plate for several millimeters, and then stripped from the mother plate for copper electrolytic purification. Manufactured by applying a process to suspend it in an electrolytic cell. Since the seed plate manufactured in this way is thin, distortion is likely to occur when it is peeled off from the mother plate, and it is difficult to ensure flatness because it is easy to bend during transportation or handling. When the flatness of the seed plate is lowered, it causes contact with the adjacent anode plate during electrolytic refining and causes a problem such as a short circuit, which may have various adverse effects such as a reduction in operation efficiency.

  On the other hand, in the copper electrorefining of the permanent cathode system, as shown in FIG. 1B, a thick base plate such as stainless steel or titanium is used as the cathode plate 4 and electrolysis is performed by the cathode beam 3 attached to the upper portion. It can be hung in the tank. Electrolytic copper is electrodeposited on the cathode plate 4 by electrolytic refining. In order to facilitate the stripping of the electrodeposited copper on both surfaces of the cathode plate 4, the left and right edges of the cathode plate 4 are made of resin or the like. An insulating material 5 is attached.

  After the electrolytic purification is completed, the electrolytic copper electrodeposited on the cathode plate is peeled off, washed and stored in a storage place as a product. After the electrodeposited electrolytic copper is stripped, the cathode plate is again placed in the electrolytic cell and the electrolytic purification is repeated. Thus, in the permanent cathode type copper electrolytic refining, the cathode plate with high flatness is repeatedly used, so that the occurrence of short-circuits can be suppressed and the process for hanging in the seed plate electrolysis process or electrolytic cell. Since no process is required, it is advantageous in terms of cost.

  As shown in FIG. 2 (a), the cathode plate used in the permanent cathode type electrolytic purification is provided with insulating materials 5 on both left and right edges. That is, the insulating material 5 is provided with a cathode plate mounting groove 6 comprising a cut groove portion 6a along the longitudinal direction for inserting a side edge of the cathode plate 4 and a stopper groove portion 6b orthogonal thereto. The upper end of the cathode plate mounting groove 6 is open, but the lower end is closed. The side edge portion of the cathode plate 4 is inserted into the cut groove portion 6 a of the cathode plate mounting groove 6, and the lower end of the cathode plate 4 is held in contact with the lower end closing portion of the cathode plate mounting groove 6. Yes. The left and right edges of the cathode plate 4 are provided with protrusions (not shown), and the protrusions engage with the stopper groove 6b of the insulating material 5.

  However, the insulating material 5 is merely fitted and held in close contact with the left and right side edges of the cathode plate 4 in order to facilitate attachment to and removal from the cathode plate 4. For this reason, it is extremely difficult to make the lower end of the cathode plate 4 and the lower end closed portion of the insulating material 5 closely contact each other, and it is inevitable that a gap in which the cathode plate mounting groove 6 is slightly opened remains between them. As a result, the electrolytic solution penetrates from the gap during the electrolytic operation, and as the electrolysis proceeds, the portion of the cathode plate 4 that should not be electrodeposited by the insulating material 5, that is, the cathode in the insulating material 5. Copper particles are electrodeposited on the plate 4.

  The copper particles electrodeposited on the cathode plate in the insulating material adhere to the electrolytic copper peeled off from the cathode plate after the completion of electrolytic purification, impair the appearance of the product electrolytic copper, or perform the electrolytic purification cycle of electrodeposition and peeling. By repeating, it grows inside the insulating material and breaks the lower end portion of the insulating material in an attempt to accompany the electrolytic copper during stripping. In addition, large growth of the copper grains causes damage to the insulating material from the inside during electrolytic refining, and causes equipment troubles such as being caught on the cathode plate transport equipment after completion of electrolytic refining.

  As a method for solving such a problem, for example, Japanese Patent Application Laid-Open No. 2006-265699 discloses an edge strip cathode plate for firmly adhering a cathode plate used in a permanent cathode method and an edge strip (insulating material). A method of attaching the edge strip to the side edge of the cathode plate after pre-filling the silicon sealant in the groove for inserting the substrate, preferably applying the silicon sealant also to the portion contacting the edge strip on the side edge of the cathode plate Are listed.

  However, this method is to apply a silicon sealant to an insulating material or the like before mounting on the cathode plate. Therefore, even if an insulating material coated with a silicon sealant is prepared, and the cathode plate and the insulating material are fixed by attaching them to the side edges of the cathode plate, the structure of both of them as shown in FIG. The lower end of the insulating material and the lower end closing portion of the insulating material cannot be in close contact with each other, and a gap in which the cathode plate mounting groove is opened remains between them, and the electrolyte enters the gap and the metal particles are electrodeposited. In addition, since the silicon sealant is applied to the entire cathode plate mounting groove of the insulating material, the insulating material and the cathode plate are firmly adhered, and the insulating material can be removed even when replacement due to aging is necessary. Have difficulty.

  Japanese Patent Laid-Open No. 2007-002282 discloses that an insulating material that is softer than the insulating material is disposed on the inner surface of the mounting groove of the insulating material that is attached to the edge of the cathode plate, and is integrally formed. By attaching a clamping tool to the opposite side of the mounting groove, and pressing the insulating material against the cathode plate with this clamping tool, the cathode plate and the insulating material (elastic material of thermoplastic elastomer) are brought into close contact with each other. A method for preventing intrusion is described.

  However, since this method requires an insulating material having a special structure with a fastening tool, it is not possible to use an ordinary insulating material that has been conventionally used for permanent cathode electrolytic purification. Moreover, even if this special structure of insulating material is used, the cathode plate and insulating material structure as shown in FIG. 2 prevents the lower end of the cathode plate and the lower end blocking portion of the insulating material from being in close contact with each other. Therefore, it was impossible to eliminate the remaining gap, and therefore it was not possible to completely prevent the electrolyte from entering from the remaining gap.

JP 2006-265699 A JP 2007-002282 A

  In view of the above-described conventional circumstances, the present invention suppresses electrodeposition of metal particles such as copper particles on the cathode plate inside the insulating material attached to both side edges of the cathode plate in the electrolytic purification of the permanent cathode method. It aims to provide a method.

  In order to achieve the above object, the electrolytic purification method of the permanent cathode method provided by the present invention is a method of attaching a cathode plate in a cathode plate mounting groove in which the lower end of the insulating material is closed when the insulating material is attached to both side edges of the cathode plate. After inserting and holding, the silicone caulking material is injected from the gap between the lower end of the cathode plate and the lower end closed portion of the cathode plate mounting groove of the insulating material, and the gap between the cathode plate existing in the cathode plate mounting groove of the insulating material The lower end portion of the portion is filled.

  According to the present invention, when the insulating material is attached to both side edges of the cathode plate, the lower end of the cathode plate and the lower end closing portion of the cathode plate mounting groove of the insulating material are opened between the two, even if they are not in close contact with each other. The gap can be filled later with a silicone caulking material to seal the gap. Therefore, even when electrolytic purification is repeatedly performed using this cathode plate, it is possible to prevent the electrolyte from entering between the cathode plate and the insulating material, and to the portion inserted into the insulating material of the cathode plate. Electrodeposition of metal particles can be suppressed.

  In addition, by suppressing the electrodeposition of the metal particles on the cathode plate in the insulating material described above, the appearance of the electrolytic copper is not impaired when the electrolytic copper is peeled off from the cathode plate after the completion of electrolytic purification. The product electrolytic copper can be obtained. In addition, it is possible to reduce the damage of the insulating material and the occurrence of equipment troubles during the operation of electrolytic purification.

  In the present invention, as shown in FIG. 2A, after the insulating material 5 is attached to both side edges of the cathode plate 4, the lower end portion of the cathode plate 4 and the lower end closing portion of the cathode plate mounting groove 6 of the insulating material 5 are As shown in FIG. 3, a silicone-based caulking material 7 is injected and filled into the gap formed without being in close contact. In order to fill the silicone-based caulking material 7, the silicone-based caulking material 7 may be injected with a caulking gun or the like using the gap remaining at the lowermost end of the cathode plate 4 sandwiched between the insulating materials 5 as the injection port 8.

  In this way, the silicone caulking material 7 is injected from the gap at the lowermost end of the cathode plate 4, and the gap between the insulating plate 5 and the cathode plate 4 existing in the cathode plate mounting groove 6 is shown in FIG. 3. Thus, by filling only the lower end portion of the gap portion with the silicone-based caulking material 7, it is possible to substantially eliminate the ingress of the electrolytic solution without filling the entire gap portion along the cathode plate mounting groove 6. As a result, the electrodeposition of the metal particles on the portion of the cathode plate 4 covered with the insulating material 5 is suppressed, so that troubles such as breakage of the insulating material 5 are reduced even if electrolytic refining is repeated. The life of the cathode plate 4 can be further extended.

  The reason for using the silicone-based caulking material in the present invention is as follows. That is, the cathode plate used in electrolytic purification is generally used in an electrolytic solution containing copper sulfate and sulfuric acid and maintained at a temperature of about 60 ° C. Does not require chemical resistance and temperature resistance. Further, when filling the caulking material, the caulking material must have an appropriate fluidity so that it can be easily injected, for example, with a caulking gun.

  Furthermore, since the caulking material is in contact with the resin insulating material, it is necessary that the compatibility with the resin is weak. This is because if the compatibility is too strong, the caulking material and the insulating material dissolve and deteriorate each other, and the frequency of refilling the caulking material and replacing the insulating material increases. In addition, when the insulating material attached to both side edges of the cathode plate deteriorates, it is necessary to replace the insulating material. However, when the old insulating material is removed during this replacement, the filled caulking material interferes. It is preferable to have an appropriate hardness so as not to occur.

  As a result of testing various commercially available caulking materials such as silicone-based, polyurethane-based, acrylic-based, acrylic urethane-based butyl rubber-based, polyisobutylene-based, etc. It turned out to be optimal. A specific example of the silicone-based caulking material is Loctite (trade name) commercially available from Henkel Japan.

[Example 1]
A stainless steel base plate was used as a cathode plate, and an insulating material made of ABS resin was attached to the left and right side edges of the cathode plate. Thereafter, as shown in FIG. 3, a silicone-based caulking material 7 was injected from the gap between the lower end of the cathode plate 4 and the lower end closed portion of the insulating material 5 using a caulking gun. At that time, only the lower end portion of the gap portion between the cathode plate 4 and the insulating material 5 was filled with the silicone-based caulking material. The silicone caulking material used is Loctite 5699 (trade name) manufactured by Henkel Japan K.K.

A plurality of 110 cathode plates with insulating plates and 111 anode plates made of crude copper were alternately placed in an electrolytic cell, and copper electrolytic purification by a permanent cathode method was performed. In addition, as a comparative example, copper electrolytic purification was performed in the same manner as described above, using the same cathode plate with an insulating material as described above except that the silicone-based caulking material was not injected. In all cases, the conditions for electrolytic purification were a current density of 320 A / m ² and an energization time of 184 hours.

  After completing one cycle of electrolytic purification under the above conditions, the electrolytic copper electrodeposited on the cathode plate was peeled off, and the state of adhesion of the copper particles to the obtained lower end portion of the electrolytic copper was confirmed. As a result, in the cathode plate filled with the silicone-based caulking material according to the present invention, the number of cathode plates (the number of lower end portions) to which copper particles adhered out of 110 pieces (the total number of lower end portions of 220) was zero. On the other hand, in the cathode plate not filled with the silicone-based caulking material according to the comparative example, the number of the lower end portions to which the copper particles adhered was extremely large as 198 out of 110 pieces (total number of the lower end portions of 220).

[Example 2]
The same conditions (current) as above using two types of cathode plates with an insulating material, the cathode plate filled with the same silicone caulking material as in Example 1 and the cathode plate not filled with the silicone caulking material according to the comparative example. The electrolytic purification with a density of 320 A / m ² and an energization time of 184 hours was repeated 10 cycles.

  The electrolytic copper electrodeposited on the cathode plate after the completion of electrolytic purification in each cycle was peeled off, and the insulating material was removed from both side edges of the cathode plate after the final 10th cycle of electrolytic purification. At that time, the cathode plate of the present invention is insulated without significant trouble since the silicone caulking material is filled only in the lower end portion of the gap portion between the cathode plate in the cathode plate insertion groove of the insulating material. The material could be removed.

  In addition, as a result of confirming the damage state of the lower end portion of the removed insulating material, in the cathode plate not filled with the silicone-based caulking material according to the comparative example, 110 sheets were grown due to the growth of the copper particles electrodeposited on the cathode plate in the insulating material. Of the 220 insulating materials attached to the cathode plate, 48 were damaged. On the other hand, in the cathode plate filled with the silicone-based caulking material according to the present invention, only 220 of the insulating materials attached to the 110 cathode plates were damaged.

It is a schematic front view of a cathode plate, (a) is a normal cathode plate, (b) is a cathode plate with an insulating material by a permanent cathode system. The state which attached the insulating material to the cathode plate is shown, (a) is a schematic front view of the side edge part of the cathode plate, (b) is a schematic sectional view along the AA line of (a). is there. It is a schematic front view which shows the side edge part of the cathode plate equipped with the insulating material by this invention.

Explanation of symbols

1 Seed plate 2 Lifter 3 Cathode beam 4 Cathode plate 5 Insulating material 6 Cathode plate mounting groove 6a Cut groove 6b Stopper groove 7 Silicone caulking material 8 Inlet

Claims (1)

  In the electrolytic refining of the permanent cathode method, when attaching an insulating material to both side edges of the cathode plate, the cathode plate is inserted and held in the cathode plate mounting groove where the lower end of the insulating material is closed, and then the lower end of the cathode plate and the insulating material It is characterized by injecting a silicone-based caulking material from the gap with the lower end blocking portion of the cathode plate mounting groove, and filling the lower end portion of the gap between the insulating plate and the cathode plate existing in the cathode plate mounting groove. Permanent cathode electrolytic purification method.

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