JP6179773B2 - Method and apparatus for casting anode for copper electrolysis - Google Patents

Description

  The present invention relates to a casting method and casting equipment for a copper electrolysis anode, and more particularly, to a method and a casting apparatus for casting a copper electrolysis anode with a mold on a turntable that rotates intermittently.

  In general, in the copper smelting process, a copper raw material is dry-smelted to refined crude copper having a copper grade of about 99.2% by weight, and the refined crude copper is cast into a mold to produce an anode for copper electrolysis. In the copper electrolysis process, electrolytic copper as a product is produced by electrolytic purification using the copper electrolysis anode as a raw material. In the copper electrolysis process, anodes and cathodes are alternately suspended in the electrolytic cell one by one, arranged and electrolyzed. Therefore, the anode for copper electrolysis is cast into a shape having a pair of drooping ears for holding the body and making electrical contact on both sides of the top of the body.

  This copper electrolysis anode is generally manufactured by a copper anode rotary casting apparatus. As the copper anode rotary casting apparatus, as schematically shown in FIG. 1, the molten copper discharged from the copper refining furnace (not shown) is singly or plural (in FIG. A plurality of copper molds 4 and 5 placed on a pair of intermittently rotating turntables 2 and 3 are poured into a predetermined amount, cooled and solidified, and then peeled off from the molds 4 and 5. Thus, a copper anode is manufactured. In the casting of the anode for copper electrolysis, while the pair of turntables 2 and 3 on which the molds 4 and 5 are placed are intermittently rotated in opposite directions, The operation of pouring molten copper at 1100 ° C. to 1150 ° C. into the molds 4 and 5 and simultaneously removing the solidified anode by cooling in the water-cooled hood 8 from the molds 4 and 5 are performed simultaneously. . To remove the anode from the mold, the turntables 2 and 3 are cast by pushing up a push-up pin (not shown) that passes through the molds 4 and 5 from below and is aligned with the upper end of the mold bottom. After the pair of hanging ears of the anode is lifted diagonally to float both ears, the anode ears are hung on the pair of hooks by the anode stripping equipment installed at the position of the stripping device 9. It is carried out by transferring to a cooling water tank.

  In the final stage of these casting processes, after removing the copper anode from the mold, it is necessary to perform a preparation operation for performing the next casting before pouring the next molten copper into the mold. As the preparatory work, the release agent spraying device 6 installed above the turntables 2 and 3 sprays or applies the slurry in which the release agent is suspended in water or the release agent aqueous solution on the inner surface of the mold. ing. As the mold release agent, clay powder, barium sulfate, fly ash, silica stone powder and the like are used. The purpose of spraying or applying a slurry in which the release agent is suspended in water or an aqueous solution of the release agent is to facilitate peeling and prevent the anode from bending during peeling. For example, a powder having a heat insulating property is sprayed or applied to prevent seizure between the mold and the rough copper and embrittlement of the mold due to high temperature, to smooth the bottom of the mold, and to smooth the surface of the anode.

When casting this anode for copper electrolysis, the molten copper generates a wave in the mold and hits the side wall when pouring into the mold after spraying or applying the mold release agent. In addition, there is a case where a portion where the molten copper adheres and is cooled and solidified is generated. Therefore, “casting” that rises significantly along the side wall of the mold is likely to occur around the stripped anode. On the other hand, in the copper electrolysis process, in order to improve the productivity per unit facility, the interval between the anode and the cathode suspended in the electrolytic cell is arranged as narrow as possible. At this time, if the “casting” is large, a short circuit occurs due to contact between the casting and the cathode. Therefore, the productivity decreases due to the decrease in the current efficiency, and the workability deteriorates due to the increase in the short correction work amount. And the quality of electrolytic copper deteriorates due to the generation of grains.
In particular, in the case where a casting is generated at the lower side of the hanging ear portion of the anode, even if the casting is crushed and the lower side portion of the ear portion is cut by pressing on the ear portion, When suspended on the anode, the suspension of the anode may be deteriorated, which further increases the short circuit of the current.

  As a countermeasure, for example, Patent Document 1 discloses a technique in which a mold release agent having poor wettability with respect to a molten metal to be cast is applied to at least an ear portion of a mold prior to pouring molten metal into the mold. Yes. Further, Patent Document 2 discloses that a mold release agent is sprayed to a predetermined place in a mold immediately before the mold stops or stops at a predetermined stop position on the turntable, and the mold is placed at the predetermined stop position after a predetermined time has elapsed. Disclosed is a method and apparatus for spraying an anti-casting agent at a predetermined location. Silicon oil, graphite powder, bone ash, and the like are used as a mold release agent or an anti-casting agent having poor wettability.

  Further, as a defect of the anode shape, a crack may occur on the side surface of the anode after casting. If the crack depth is about 1/3 or less of the anode thickness, there is no effect on the subsequent electrolysis process, but if a crack with a depth greater than this occurs, the anode will be dissolved as the electrolysis time increases. Therefore, the anode is cut along the crack, and the anode fragment or the anode itself falls into the electrolytic cell. If the anode debris falls, the electrolysis operation must be stopped and the removal operation must be carried out. Not only is the work involved in danger, but also a decrease in productivity due to a decrease in energization time, adhesion of anode slime, etc. It will cause deterioration of the quality of electrolytic copper.

  As a countermeasure against the crack, Patent Document 3 discloses that a release agent having a higher thermal conductivity than barium sulfate is sprayed on the center of the mold, and a release agent having a lower thermal conductivity than the release agent having a higher thermal conductivity. Techniques have been proposed for spraying the peripheral edge of the mold. Specifically, after spraying clay water as a mold release agent only on the mold bottom surface, this method sprays barium sulfate slurry as a mold release agent for crack prevention on the mold side surface, thereby casting the anode side surface after casting. It solves the problem of cracking. However, this method has a problem that “swelling” occurs on the anode surface in a portion where the clay water and the barium sulfate slurry are mixed. This is because when a plurality of types of release agents are sprayed at the same stop position of the mold, mixing of the release agent slurry in an undried state in the mold cannot be avoided. That is, immediately after spraying clay water on the bottom of the mold, when slurry of barium sulfate was sprayed on the side of the mold as a mold release agent for crack prevention, the clay water in the mold and the slurry of barium sulfate were mixed. In the portion, the release agent moisture is difficult to dry, and the molten metal may be poured with moisture remaining on the mold. At this time, the water remaining on the bottom of the mold at the bottom of the molten copper after pouring the molten copper becomes water vapor, but solidification of the molten copper surface proceeds before the water vapor escapes from the molten copper surface to the atmosphere. For this reason, a portion in which the inside raised from several mm to several tens of mm becomes a cavity is formed on the surface of the anode. This raised part is a “bulge”. When “blowing” occurs on the anode surface, a problem similar to that when “casting” occurs is caused. In other words, a large “bulge” and the cathode contact each other to cause a short circuit of the current, resulting in a decrease in productivity due to a decrease in current efficiency, a deterioration in workability due to an increase in the amount of short correction work, and the occurrence of grains. The quality of electrolytic copper will deteriorate.

JP 59-133966 A JP 2001-191171 A JP 2012-183556 A

  The present invention has been made to solve the problems of the method described in Patent Document 3, and intermittently moves a copper electrolysis anode having a pair of hanging ears on both sides of the top of the anode body. A method for casting an anode for copper electrolysis capable of preventing the occurrence of cracks on the side surface of the anode after casting while preventing the occurrence of swelling of the anode surface after casting when casting with the mold on the turntable The object is to provide a casting apparatus.

In order to solve the problems of the prior art described above, the inventors of the present invention have made extensive studies focusing on the method of spraying the mold release agent into the mold, and as a result, when spraying multiple types of mold release agents, Sprinkling with consideration of timing so that the multiple types of mold release agents do not mix in the mold, preventing the occurrence of cracks on the side of the anode after casting and the occurrence of swelling on the anode surface after casting It was found that an anode having a good shape can be obtained.
That is, the method for casting an anode for copper electrolysis according to the present invention involves casting a copper electrolysis anode having a pair of hanging ears on both sides of the top of the anode body with a mold on a turntable that rotates intermittently. Each time the turntable makes one turn, the slurry of clay water or barium sulfate is alternately sprayed as a mold release agent on the casting surface in the mold. The copper electrolysis anode casting apparatus according to the present invention comprises an intermittently rotating turntable for casting a copper electrolysis anode having a pair of hanging ears on both sides of the top of the anode body with a mold. The anode casting apparatus provided includes a spraying device that alternately sprays clay water or barium sulfate slurry at the same stop position of the mold on the turntable every time the turntable makes one turn. is there.

  According to the casting method and apparatus for an anode for copper electrolysis of the present invention, two mold release agents, clay and barium sulfate, are alternately used every time the turntable makes one turn, so that one mold release agent is a mold. As the mold is dried by the residual heat of the mold, a part of the mold release agent remains in the mold. Therefore, it is possible to prevent the occurrence of cracks on the side surface of the anode after casting while preventing the occurrence of swelling of the anode surface after casting. it can. In addition, it is possible to prevent the anode fragments from falling into the electrolytic cell in the copper electrolysis process, and to reduce the occurrence of short-circuit current. Electrolytic operation can be realized, and at the same time, high-quality electrolytic copper can be produced.

It is a schematic plan view which shows one Example of the copper anode rotary casting apparatus which concerns on this invention. It is a schematic flowchart which shows the mold release agent spreading | diffusion apparatus in a copper anode rotary casting apparatus same as the above.

The copper anode rotary casting apparatus shown in FIG. 1 includes a pouring block 7 on a large number of copper molds 4 and 5 placed on a pair of turntables 2 and 3 that rotate and move intermittently in opposite directions as described above. In this method, the copper anode is casted by pouring a fixed amount at a time, and removing the anode solidified by cooling in the water-cooled hood 8 from the molds 4 and 5 by the stripping device 9.
In the copper anode rotary casting apparatus according to the present invention, every time the turntables 2 and 3 make one turn by the release agent spraying apparatus 6 installed above the turntables 2 and 3, clay water or A method of alternately spraying barium sulfate slurry is adopted, and the release agent spraying device 6 includes a barium sulfate slurrying tank 6A-1, a supply pipe 6A-2, as shown in FIG. A barium sulfate slurry supply system 6A comprising a supply pump 6A-3, a switching valve 6A-4, a flow rate control valve 6A-5, and a barium sulfate slurry spray nozzle (for mold side surface) 6A-6, and a clay powder slurrying tank 6B-1 A clay water supply system 6B comprising a supply pipe 6B-2, a supply pump 6B-3, a switching valve 6B-4, a flow rate adjusting valve 6B-5, and a clay water spray nozzle (for mold bottom surface) 6B-6, and the supply distribution Is composed of a pipe was a changeover valve 6C-1 with the communicating pipe 6C between 6A-2 and 6B-2.

  In the present invention, two types of clay and barium sulfate were particularly selected as the mold release agent. As described above, clay has the action of preventing the mold and the copper from being seized and preventing the mold from becoming brittle due to high temperature. This is because it is excellent as a heat insulating material and a surface smoothing agent, and barium sulfate has an action of preventing the occurrence of casting and maintaining the shape quality of the anode. In addition, the thermal conductivity of barium sulfate as a solid is 1.31 W / m · K, and the thermal conductivity of general clay is about 0.7 to 1.5 W / m · K. Therefore, if the thermal conductivity of the solid itself is compared, barium sulfate and clay are almost the same.

The main feature of the present invention is that the above two types of release agents, clay and barium sulfate, are used alternately each time the turntable makes one round, and the reason is as follows.
That is, as described above, after spraying clay water as a mold release agent on the mold bottom surface, spraying barium sulfate slurry as a mold release agent on the mold side surface to prevent cracks on the anode side surface after casting. The problem that occurs can be solved, but if the slurry of barium sulfate is sprayed on the side of the mold immediately after the clay water is sprayed on the mold bottom surface, In the part where the release agent slurry in the state is mixed and the clay water and the barium sulfate slurry are mixed, the release agent moisture becomes difficult to dry, and the molten metal is poured in a state where moisture remains in the mold, Since the water remaining on the bottom of the mold at the bottom of the molten copper after pouring the molten copper becomes water vapor, solidification of the molten copper surface proceeds before the water vapor escapes from the molten copper surface to the atmosphere. "Blister" occurs on the surface. In the present invention, as a means for preventing the occurrence of the “blowing”, two types of release agents, clay and barium sulfate, are alternately used every time the turntable makes one round. In other words, two types of release agents, clay and barium sulfate, are used alternately each time the turntable makes one turn, so that one release agent is dried by the residual heat of the mold, and a part of the release agent is the mold. As a result, the inner surface of the mold is layered with clay, which is excellent as a heat insulating material and surface smoothing agent, and barium sulfate, which can maintain good shape quality of the anode, and cracks on the side surface of the anode after casting It is possible to prevent the occurrence of blistering on the anode surface after casting, while preventing the occurrence of the occurrence of the anode, so that an anode having a good shape can be cast.

Next, a method of casting an anode for copper electrolysis using the copper anode rotary casting apparatus shown in FIGS. 1 and 2 will be described.
In the copper anode rotary casting apparatus shown in FIG. 1, the two turntables 2 and 3 that rotate and move intermittently rotate one block in 12 to 13 seconds, and move 12 blocks to a fixed position after moving one block. It is operated in a cycle of stopping for 13 seconds. The turntable rotates in the direction of the arrow shown in FIG. Since one mold becomes one block, the turntables 2 and 3 make one turn in 7 to 8 minutes. Molten copper is poured into the molds 4 and 5 at the position of the pouring block 7, sprayed and cooled in the water cooling hood 8, and then taken out from the mold as an anode at the position of the stripping device 9. A mold release agent is sprayed from a mold release agent spraying nozzle by a mold release agent spraying device 6 to the emptied mold, and then molten copper is poured at a position of a pouring block 7.

In the present invention, in the first turn of the two turntables 2 and 3 that rotate intermittently, barium sulfate slurry is sprayed with a barium sulfate slurry spray nozzle (for mold side surface) 6A-6 of the release agent spray device 6 and It sprays from the clay water spray nozzle (for mold bottom surface) 6B-6. When spraying barium sulfate slurry, the switching valve 6B-4 of the clay slurry supply system 6B is closed, and the switching valve 6A-4 of the barium sulfate slurry supply system 6A and the switching valve 6C-1 of the communication pipe 6C are opened. . The barium sulfate slurry sprayed into the molds 4 and 5 is dried by the residual heat of the molds, and the molten copper is poured into the molds 4 and 5 at the pouring block 7 and solidified by cooling in the water cooling hood 8. Is removed from the molds 4 and 5 by the peeling device 9. At this time, most of the barium sulfate in the mold adheres to the anode and is taken out, but part of the barium sulfate remains in the molds 4 and 5. Subsequently, in the second turn of the turntables 2 and 3, clay water is sprayed with the clay water spray nozzle (for the mold bottom surface) 6B-6 and the barium sulfate slurry spray nozzle (for the mold side surface) 6A-6 of the release agent spray device 6. Scatter from. When spraying clay water, the switching valve 6A-4 of the barium sulfate slurry supply system 6A may be closed, and the switching valve 6B-4 of the clay water supply system 6B and the switching valve 6C-1 of the communication pipe 6C may be opened. At this time, since a part of the previous barium sulfate remains in the molds 4 and 5 from which the anode has been peeled off, the inner surfaces of the molds 4 and 5 do not mix clay and barium sulfate. It will be in the state where it piled up in layers. In this state, the molten copper is poured again into the molds 4 and 5 at the pouring block 7, and the anode solidified by cooling in the water-cooled hood 8 is removed from the molds 4 and 5 by the stripping device 9. The Thereafter, the same process as described above is repeated to manufacture the anode.
Thus, according to the present invention, by alternately using two types of release agents of clay and barium sulfate every time the turntable makes one turn, mixing of clay and barium sulfate can be prevented. It is possible to cast an anode having a good shape without cracks on the anode side surface and without swelling on the anode surface.

  It should be noted that either the barium sulfate slurry or the clay water may be sprayed before or after. The operation of the switching valves 6A-4 and 6B-4 and the switching valve 6C-1 of the communication pipe 6C in each supply system of the barium sulfate slurry and the clay water of the release agent spraying device 6 is performed under the set conditions (barium sulfate and clay If you input the water order, switching method for each lap, every two laps, etc.) and the mold lap number signal (first lap, second lap, etc.) is detected by a sensor etc., a simple sequence Can be automated. Furthermore, the amount of spraying from each of the spraying nozzles 6A-6 and 6B-6 may be adjusted by, for example, the flow rate adjusting valves 6A-5 and 6B-5 shown in FIG. This control valve may be installed for each nozzle for finer adjustment.

  Hereinafter, based on an Example, this invention is demonstrated more concretely. However, the present invention is not limited by the following examples, and all modifications and implementations within the scope not departing from the spirit are included in the technical scope of the present invention.

The copper anode rotation shown in FIG. 1 and FIG. 2 provided with turntables 2 and 3 that rotate and move intermittently in a cycle of rotating one block in 12 to 13 seconds and stopping for 12 to 13 seconds after moving one block. In the casting apparatus, every time the turntable makes one turn, the release agent spray nozzles (side spray nozzles and bottom spray nozzles) 6A-6 and 6B-6 installed in the release agent spray device 6 Then, 1100 ° C. molten copper was poured into each mold to produce an anode for copper electrolysis.
In this embodiment, when the mold on the turntable is stopped immediately below the release agent spraying device, the slurry of barium sulfate and the clay water are alternately alternately supplied in this order from the release agent spray nozzle of the release agent spraying device. Sprayed for 5-6 seconds. In addition, the slurry of barium sulfate is obtained by suspending 250 g of barium sulfate in 1.1 to 1.5 liters of water per mold, and the clay water is 1.10 g of clay per mold. It is suspended in 1 to 1.5 liters of water.
After casting in this manner, a total of 200 anodes were extracted from the copper electrolysis anodes produced in 10 different casting lots, 20 each. The number of anodes manufactured in one casting lot is about 1300. Table 1 shows the inspection results obtained by visual inspection of the extracted anodes one by one with respect to the occurrence of cracks and counting the number of anodes with cracks.

Using the same copper anode rotary casting device as in Example 1, each time the turntable makes one turn, the release agent spray nozzle (side spray nozzle and bottom spray nozzle) 6A installed in the release agent spray device 6 From -6 and 6B-6, the same barium sulfate slurry and clay water as in Example 1 were sprayed alternately in the same order as in Example 1, and molten copper at 1150 ° C. was poured into each mold to perform copper electrolysis. An anode was produced.
In this embodiment, when the mold on the turntable is stopped immediately below the release agent spraying device, the clay water and the barium sulfate slurry are alternately alternately supplied in this order from the release agent spray nozzle of the release agent spraying device. Sprayed for ~ 6 seconds.
After casting in this manner, a total of 200 anodes were extracted from the copper electrolysis anodes produced in 10 different casting lots, 20 each. The number of anodes manufactured in one casting lot is about 1300. Each of the extracted anodes is visually inspected for the occurrence of blisters one by one, and the inspection results obtained by tabulating the number of anodes with blisters are shown in Table 2.

[Conventional example 1]
Using the same copper anode rotary casting apparatus as in Example 1, 11 to 12 seconds after the mold on the turntable starts rotating from the previous block, that is, immediately before stopping at the position of the release agent spraying apparatus. Sprinkle clay water from the bottom spray nozzle for about 5-6 seconds, then 8-9 seconds after the mold stops at the mold release agent spray device, that is, spraying of clay water from the bottom spray nozzle is completed Then, about 3 to 5 seconds later, silicon oil was sprayed from the side spray nozzle for about 2 to 3 seconds, and molten copper at 1100 ° C. was poured into each mold to produce an anode for copper electrolysis. In addition, the silicone oil used the emulsion type silicone mold release agent YMR7212 manufactured by Momentive Co., Ltd., and a solution obtained by diluting the stock solution 10 times with water was sprayed to 75 to 80 mL per mold.
After casting in this manner, a total of 200 anodes were extracted from the copper electrolysis anodes manufactured in 10 different casting lots, each of which was cracked, one for each of the extracted anodes. Table 1 and Table 2 also show the inspection results of the total number of anodes in which cracks and blisters were generated by visual inspection for occurrence of blisters.

[Conventional example 2]
Using the same copper anode rotary casting apparatus as in Example 1, 11 to 12 seconds after the mold on the turntable starts rotating from the previous block, that is, immediately before stopping at the position of the release agent spraying apparatus. Then, spray clay water from the bottom spray nozzle for about 5 to 6 seconds, then 8 to 9 seconds after the mold stops at the mold release agent spray device, that is, spraying of clay water from the bottom spray nozzle is completed. About 3 to 5 seconds after that, the barium sulfate slurry was sprayed from the side spray nozzle for about 2 to 3 seconds, and molten copper at 1150 ° C. was poured into each mold to produce an anode for copper electrolysis. The barium sulfate slurry is obtained by suspending 250 g of barium sulfate in 1.1 to 1.5 liters of water per mold.
After casting in this manner, a total of 200 anodes were extracted from the copper electrolysis anodes manufactured in 10 different casting lots, each of which was cracked, one for each of the extracted anodes. Table 1 and Table 2 also show the inspection results of the total number of anodes in which cracks and blisters were generated by visual inspection for occurrence of blisters.

  As is apparent from the results shown in Table 1, the amount of crack generation in Example 1 is significantly reduced compared to Conventional Example 1 (the prior art described in Patent Document 2), and Conventional Example 2 (Patent Document 2). The amount of crack generation is the same as that of the prior art described in No. 3. Further, as is clear from the results shown in Table 2, in Example 2, the amount of swelling generated is significantly reduced as compared with Conventional Example 2 (the prior art described in Patent Document 3). From this, it can be seen that according to the present invention, the effect of preventing the occurrence of swelling of the anode surface after casting can be obtained while preventing the occurrence of cracks on the side surface of the anode after casting.

DESCRIPTION OF SYMBOLS 1 Reservoir 2, 3 Turntable 4, 5 Mold 6 Release agent spraying device 6A Barium sulfate slurry supply system 6A-1 Barium sulfate slurrying tank 6A-2, 6B-2 Supply piping 6A-3, 6B-3 Supply pump 6A-4, 6B-4, 6C-1 Switching valve 6A-5, 6B-5 Flow control valve 6A-6 Barium sulfate slurry spray nozzle (for mold side)
6B Clay water supply system 6B-1 Clay powder slurrying tank 6B-6 Clay water spray nozzle (for mold bottom)
6C Communication pipe 7 Pouring block 8 Water cooling hood 9 Stripping device

Claims (2)

When a copper electrolysis anode having a pair of hanging ears on both sides of the top of the anode body is cast with a mold on a turntable that rotates intermittently, casting is performed in the mold every time the turntable makes one turn. A casting method for an anode for copper electrolysis, characterized in that a slurry of barium sulfate and clay water or a slurry of clay water and barium sulfate are alternately sprayed on the surface in that order . In an anode casting apparatus having an intermittently rotating turntable for casting a copper electrolysis anode having a pair of hanging ears on both sides of the top of the anode body with a mold, every time the turntable makes one turn Casting of an anode for copper electrolysis comprising a spraying device for alternately spraying barium sulfate slurry and clay water or clay water and barium sulfate slurry in that order at the same stop position of the mold on the turntable apparatus.