Method for manufacturing electrolytic anode

Abstract

To provide a method for producing an anode for electrolysis capable of suppressing the generation of the blister on the anode surface without producing the problem that the anode burns to a mold.SOLUTION: A casting step for successively casting a molten crude metal to plural anode molds 12 provided on an intermittently rotating turn table 11, a cooling step for cooling the cast molten crude metal, a removing step for removing an anode A for electrolysis solidified by the cooling from the anode mold 12 and a release agent scattering step for scattering release agent slurry into the anode mold 12 directly after the removal of the anode A for electrolysis while dispersing the same with a gas for dispersion are repeatedly performed, and preferably, after the completion of the release agent scattering step, a piping cleaning step for introducing a gas for cleaning into a feed piping 22 of the release agent slurry to exhaust the remaining release agent slurry is further performed.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for producing an anode for electrolysis used in an electrolytic refining process. [Background technology]

[0002] In the non-ferrous metal refining process, the grade of the molten non-ferrous metal is gradually increased by dry processing, and then electrolytic refining is finally performed to produce high-purity non-ferrous metals. For example, in the electrolytic refining of copper, the molten refined blister copper with a purity of about 99.5% produced by oxidizing and reducing the blister copper in the previous refining furnace is cast into a roughly rectangular plate, and anodes (hereinafter referred to as "anodes") made of multiple copper plates and multiple separately prepared cathodes (hereinafter referred to as "cathodes") are alternately arranged one by one and immersed in the electrolyte in an electrolytic cell, and a voltage is applied to them to produce electrolytic copper.

[0003] The above-mentioned copper electrolytic refining is classified into a permanent cathode method (hereinafter referred to as the "PC method") and a conventional method (hereinafter referred to as the "seed plate method") depending on the type of cathode used. In the former PC method, a stainless steel thin plate is used as the cathode, and the electrolytic copper electrodeposited on the thin plate is peeled off from the thin plate in a subsequent peeling process and shipped as a product, and the thin plate is reused. On the other hand, in the latter seed plate method, a thin plate-shaped seed plate made of high purity copper is used as the cathode, and the electrolytic copper electrodeposited on the seed plate is shipped as a product together with the seed plate.

[0004] In the above-mentioned copper electrolytic refining, in order to increase productivity, the anode and the cathode are arranged as close to each other as possible in the electrolytic cell, so if the surface of the anode body is uneven, the anode and the cathode may come into contact with each other and cause a short circuit. If a short circuit occurs in the electrolytic cell, the electrolytic efficiency decreases, so in the above-mentioned casting of refined blister copper, it is desirable to mold a smooth anode without unevenness on its surface.

[0005] One of the reasons for the unevenness of the anode surface is thought to be the anode sticking to the mold during casting. As a countermeasure to this, Patent Document 1 discloses a technique for forming a layer of a mold release agent made of clay powder and water glass on the inner surface of the anode mold before pouring the molten metal. It is described that this prevents the anode from sticking during casting and allows the molding of a smooth anode with no unevenness on the surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 2896764 specification Summary of the Invention [Problem to be solved by the invention]

[0007] As shown in the above Patent Document 1, by forming a layer of a release agent (hereinafter referred to as "release layer") on the inner surface of the anode mold, it is possible to prevent problems such as seizure during casting and the resulting unevenness of the anode surface, but since the release layer is formed by spraying a release agent slurry prepared by adding water to the release agent onto the anode mold, a convex part (hereinafter referred to as "blister") like a blister formed of a thin film with a hollow inside may occur on the surface of the anode. If such a blister occurs on the surface of the anode, the current is preferentially consumed in the blister during electrolysis, and as a result, some of the blisters may break or peel off, which may cause the above-mentioned short circuit problem.

[0008] One of the causes of the occurrence of blistering on the surface of the anode is considered to be poor drying of the release agent slurry poured into the anode mold so as to spread over the entire inner surface. In other words, if the evaporation of moisture from the release agent slurry poured into the anode mold before the anode is cast is not completed before the molten blister copper is poured, the residual moisture will turn into steam bubbles when the molten blister copper is poured, and a phenomenon will occur in which the film on the surface of the molten copper is pushed up. As a countermeasure against this, it is considered to reduce the moisture contained in the release agent slurry to suppress the occurrence of blistering. However, if the amount of moisture contained in the release agent slurry is reduced, the fluidity of the release agent slurry will decrease, making it difficult for the release agent components to reach every corner of the mold, which may cause problems such as the anode being burned onto the mold or the release agent components clogging the spraying device for the release agent slurry.

[0009] Incidentally, when a release agent slurry is sprayed on the mold immediately after the anode is peeled off, the moisture contained in the release agent slurry evaporates due to the heat of the mold exceeding 100°C, but the inventors thought that since the release agent components such as clay powder contained in the mold agent slurry have an insulating effect, the heat transfer to the moisture in the mold agent slurry is hindered and the moisture does not evaporate completely until the molten blister copper is poured, and this may cause the swelling. It is thought that moisture is more likely to remain in the mold during winter or when the mold temperature is lower than usual because a long time has passed since the casting operation of the previous batch.

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a method for producing an anode for electrolysis that can suppress the occurrence of blistering on the surface of the anode without causing the problem of the anode being burned onto a mold by shortening the time it takes for the water contained in a release agent slurry to evaporate. [Means for solving the problem]

[0011] In order to achieve the above object, the method for producing an anode for electrolysis of the present invention includes a casting step of sequentially casting molten crude metal into a plurality of anode molds provided on an intermittently rotating turntable, a cooling step of cooling the cast molten crude metal, a stripping step of peeling off the anode for electrolysis solidified by the cooling from the anode mold, and a step of removing the anode for electrolysis from the anode mold immediately after the anode for electrolysis has been peeled off. The solid content of the clay is 120-160g / L. Release agent slurry Using the emission part The release agent is dispersed by a dispersion gas while being dispersed. and scanning the emission portion in one direction along the bottom surface of the mold recess of the anode mold. It is characterized by: Effect of the Invention

[0012] According to the present invention, it is possible to suppress the occurrence of blistering on the surface of the anode for electrolysis without causing the problem of the anode for electrolysis being burned onto the anode mold. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic plan view of an electrolytic anode casting apparatus to which a method for producing an electrolytic anode according to an embodiment of the present invention can be suitably applied. [Diagram 2] FIG. 2 is a plan view of an electrolysis anode produced by the electrolysis anode casting apparatus of FIG. 1. [Diagram 3] FIG. 2 is a perspective view of an anode mold provided on a turntable of the electrolytic anode casting apparatus of FIG. 1. [Figure 4] FIG. 2 is a schematic flow diagram of a specific example of a release agent slurry supplying device used in a release agent spraying step and a pipe cleaning step in the manufacturing method for an electrolytic anode according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic diagram of a specific example of a mechanism for scanning the release agent slurry discharge portion of FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the method for producing an anode for electrolysis of the present invention will be described, taking as an example a case where the anode for electrolysis is a copper electrolysis anode used in electrolytic refining in a copper smelting process. First, an electrolysis anode casting apparatus in which the method for producing an anode for electrolysis of the present invention can be suitably carried out will be described.

[0015] 1. Anode casting equipment for electrolysis As shown in FIG. 1 , an electrolysis anode casting apparatus 10 that continuously produces electrolysis anodes from molten blister copper is mainly composed of a turntable 11 that rotates intermittently in the direction of the white arrow, a plurality of anode molds 12 that are arranged on the turntable 11 at equal intervals in the circumferential direction, a trough section 13 that sequentially pours molten blister copper refined in a previous-stage refining furnace into these plurality of anode molds 12, a cooling device 14 that cools the molten blister copper cast into the anode mold 12, a stripping machine 15 that strips the electrolysis anodes that have been solidified by cooling in the cooling device 14 from the anode mold 12, and a release agent spraying section 16 that sprays a slurry release agent into the anode mold 12 to improve releasability during stripping. Although FIG. 1 shows an example in which 12 anode molds 12 are provided on the turntable 11, the number of anode molds is not limited to this, and generally, about 20 anode molds are provided on the turntable.

[0016] The electrolysis anode produced by the above-mentioned electrolysis anode casting apparatus 10 is immersed in the electrolyte in an electrolytic cell in a suspended state in the next step of electrolytic refining, and therefore has a characteristic shape as shown in the front view of Fig. 2. Specifically, the electrolysis anode A shown in Fig. 2 is composed of an anode main body in the shape of a substantially rectangular plate with dimensions of about 1000 mm in length and 1000 mm in width, and a pair of hanging ears protruding from both upper ends of the anode main body, and the anode main body can be immersed in the electrolyte in the electrolytic cell by placing the pair of hanging ears on opposing side walls of the electrolytic cell.

[0017] 2. Manufacturing method of electrolysis anode The method for producing an anode for electrolysis according to an embodiment of the present invention, which is carried out using the anode casting apparatus 10 for electrolysis as described above, repeatedly carries out the following steps: a casting step in which molten blister copper is successively cast into a plurality of anode molds 12 placed on a turntable 11 that rotates intermittently in the direction of the white arrow; a cooling step in which the molten blister copper cast into the anode mold is cooled; a stripping step in which the anode A for electrolysis solidified by cooling in the cooling step is peeled off from the anode mold 12; a release agent spraying step in which a release agent slurry is sprayed into the anode mold 12 immediately after the anode A for electrolysis has been peeled off, while being dispersed with a dispersion gas; and a pipe cleaning step in which, after dispersion of the release agent slurry has been completed, a cleaning gas is introduced into a supply pipe for the release agent slurry as necessary to discharge the release agent slurry remaining in the supply pipe.

[0018] In the manufacturing method of the anode for electrolysis according to the embodiment of the present invention, the release agent slurry is dispersed by the dispersion gas and then sprayed onto the anode mold 12, so that the release agent slurry can be widely sprayed onto the inner surface of the anode mold 12, and therefore the water contained in the release agent slurry can be evaporated quickly. In addition, the dispersion gas plays a role in spreading the release agent in place of water or in cooperation with water, so that the amount of water contained in the release agent slurry can be reduced, and therefore the time required for the water to evaporate can be further shortened.

[0019] This makes it possible to manufacture a smooth electrolysis anode A with almost no blistering on the surface, without the problem of seizing in the mold. As a result, in the subsequent electrolytic refining process, the occurrence rate of short circuits between the anode and the cathode caused by unevenness such as blistering on the surface of the electrolysis anode A can be reduced, and the productivity of the copper refining process can be significantly improved.

[0020] In addition, by carrying out a pipe cleaning step as necessary, it is possible to prevent the release agent slurry from remaining in the supply pipe, and therefore it is possible to suppress the problem of the release agent slurry of high concentration or the solid content, which is generated by solid-liquid separation of the remaining release agent slurry, accumulating in the supply pipe or clogging the supply pipe. Furthermore, since the concentration of the release agent slurry sprayed to the next anode mold through the supply pipe becomes constant, it is possible to suppress the variation in the time required for the water contained in the release agent slurry to evaporate from one anode mold to another. Each of the above-mentioned casting step, cooling step, stripping step, release agent spraying step, and pipe cleaning step will be described in more detail below.

[0021] 2.1 Casting process The casting process is a process in which refined blister copper, which has been increased to a purity of about 99.5% in a previous refining furnace, is successively cast through the gutter section 13 into the anode molds 12 which are transported one after another below the gutter section 13 by the intermittent rotation of the turntable 11. This gutter section 13 is generally composed of a flow gutter, a retention gutter and a metering gutter, which allows a constant amount of refined blister copper to be cast into the mold recess 12a of each anode mold 12, making it possible to manufacture electrolysis anodes A with little variation.

[0022] 2.2 Cooling process The cooling step is a step in which the anode mold 12 filled with the refined blister copper cast in the previous casting step is successively introduced into a hood-shaped cooling device 14 by the rotation of the turntable 11, and the refined blister copper is cooled by spraying cooling water preferably from above and below through cooling water spray piping. This cooling causes the refined blister copper to solidify in the mold recess 12a, and the electrolysis anode A is formed. In this cooling step, the anode mold 12 is also cooled to an appropriate temperature at the same time as the refined blister copper is cooled.

[0023] 2.3 Stripping process The stripping step is a step in which the electrolysis anode A molded by cooling in the preceding cooling step is stripped from the mold recess 12a of the anode mold 12. In stripping the electrolysis anode A, a method is generally adopted in which a portion of the electrolysis anode A near the lug is pushed up by a push-up pin 12b protruding from the bottom of the mold recess 12a, and this pushed-up portion is hooked or gripped by a stripper 15 to remove it from the anode mold 12. Note that before the electrolysis anode A is stripped by the stripper 15, an irregular anode stripping device may be provided to strip off defective anodes that have been determined to be defective by visual inspection or the like.

[0024] 2.4 Release agent spraying process The release agent spraying step is a step of spraying a release agent slurry prepared to a predetermined solid content concentration into the mold recess 12a of the anode mold 12 after the electrolysis anode A has been peeled off in the previous step. The moisture contained in the sprayed release agent slurry evaporates due to the heat storage held by the anode mold 12, thereby forming a release layer on the inner surface of the mold recess 12a. In the casting step of the next cycle, refined crude copper is cast on this release layer, so that the releasability of the electrolysis anode A from the anode mold 12 can be improved. The evaporation of the moisture contained in the release agent slurry sprayed in this release agent spraying step needs to be completed immediately after the electrolysis anode is peeled off in the previous peeling step, and before the casting step of the next cycle begins. Therefore, in order to quickly evaporate the moisture contained in the release agent slurry, it is desirable to set the temperature of the anode mold 12 immediately after the electrolysis anode is peeled off to 100°C or higher.

[0025] In the above-mentioned spraying of the release agent slurry, the release agent slurry is mixed with a dispersion gas, so that the release agent slurry can be sprayed in a dispersed state in the dispersion gas into the mold recess 12a of the anode mold 12. By dispersing the release agent slurry in the dispersion gas in this way, the release agent slurry is sprayed in a mixed state of three phases, namely, the solid release agent, moisture, and gas. This makes it possible to widely spray the release agent slurry on the inner surface of the mold recess 12a, and the moisture contained in the release agent slurry can be evaporated more quickly. In addition, the role of spreading the release agent can be assigned to the dispersion gas in the same way as water, so that the moisture content of the release agent slurry can be reduced. That is, a release agent slurry having a higher solid content concentration than in the past can be used, so that the time required for the moisture contained in the release agent slurry to evaporate can be further shortened.

[0026] When the water content of the release agent slurry is reduced as described above, it is usually difficult to uniformly spray the release agent onto the inner surface of the mold recess 12a. However, as will be described later, by making the release agent slurry supplied from the supply pipe and released in a mixed state with a dispersion gas scan in one direction along the bottom surface of the mold recess 12a of the anode mold 12, or by making the flow rate of the release agent slurry flowing through the supply pipe variable by, for example, adjusting the opening of a valve, it becomes possible to uniformly spray the release agent onto the inner surface of the mold recess 12a even if the water content is reduced to a certain extent.

[0027] The solid content concentration, which is the solid content mass per unit volume of the release agent slurry, is preferably in the range of 20 to 160 g / L, more preferably in the range of 80 to 120 g / L. If the solid content concentration is less than 20 g / L, the water may take too long to evaporate, causing a problem of swelling, and conversely, if the solid content concentration exceeds 160 g / L, the release agent slurry is likely to clog the supply pipe. The amount of the release agent slurry used may be an amount sufficient to spread the release agent slurry over the entire inner surface of the mold recess 12a of the anode mold 12, and at a normal mold temperature, it is preferably about 500 to 3600 mL per square meter of the size of the anode body of the electrolysis anode, more preferably about 900 to 1800 mL.

[0028] The dispersion gas is supplied at an appropriate pressure, for example, within a range of 100 kPaG to 1 MPaG, so as to balance with the head pressure of the release agent slurry, which changes depending on the pressure loss occurring in the piping path, the discharge part, etc. The supply pressure of the dispersion gas can be adjusted, for example, by adjusting the opening of the supply valve of the dispersion gas while visually checking the dispersion state of the release agent slurry so that the range in which the release agent slurry is dispersed matches the size of the mold recess 12a without scattering over a wide area.

[0029] 2.5 Piping cleaning process The pipe cleaning step is a step in which, after the dispersion of the release agent slurry is completed, a cleaning gas is introduced into the supply pipe of the release agent slurry as necessary, thereby discharging the release agent slurry remaining in the supply pipe. By introducing the cleaning gas after the dispersion of the release agent slurry is completed in this way, the amount of the release agent slurry remaining in the supply pipe can be minimized and the consumption of the cleaning gas can be saved.

[0030] As described above, by discharging the release agent slurry remaining in the supply pipe using the cleaning gas, clogging of the supply pipe can be prevented. In addition, since the release agent slurry remaining in the supply pipe is not carried over to the release agent spraying step of the next cycle, a constant amount of release agent slurry with a constant concentration can be sprayed to each anode mold at all times, and the time required for the water to evaporate can be prevented from varying for each anode mold. In addition, problems such as the release agent being wasted or the water taking too long to evaporate can be suppressed.

[0031] The release agent slurry remaining in the supply pipe may be discharged to either the anode mold side or the supply source (storage tank) of the release agent slurry, or may be discharged to both. In either case, the release agent can be effectively utilized without waste. When discharging the release agent slurry remaining in the supply pipe to the anode mold side, it is preferable to start rotating the turntable 11 after cleaning by introducing the cleaning gas is completed. There is no particular limitation on the composition of the gas used for the dispersion gas and cleaning gas, but it is preferable to use any one of air, nitrogen, and water vapor, and it is more preferable to use compressed air because it is easy to handle and inexpensive. Separate gases may be used for the dispersion gas and the cleaning gas, but it is preferable to use the same gas because the supply sources for them can be shared.

[0032] 3. Release agent slurry supply device Next, a specific example of a release agent slurry supplying device used in the above-mentioned release agent spraying step and pipe cleaning step will be described. As shown in Fig. 4, the release agent slurry supplying device supplies the release agent slurry to the anode mold immediately after the electrolysis anode is peeled off. The release agent slurry supplying device is composed of a storage tank 20 as a release agent slurry supply source for temporarily storing the release agent slurry prepared to a predetermined concentration, a pump 21 for pressurizing the release agent slurry discharged from the bottom of the storage tank 20, a supply pipe 22 for sending the release agent slurry pressurized by the pump 21 to the spraying position, and a discharge part 23 such as a nozzle provided at the tip of the supply pipe 22 for spraying the release agent slurry in a state dispersed in a dispersion gas.

[0033] Since the solid content such as the release agent is contained in the release agent slurry in a state of being suspended in a dispersion medium such as water, the solid content easily settles due to the difference in specific gravity and separates from the dispersion medium. For this reason, the storage tank 20 is provided with an agitator 20a, which prevents the solid content from being separated from the dispersion medium. Furthermore, the composition of the release agent slurry can be made more uniform by continuously performing external circulation in which the release agent slurry is extracted from the bottom of the storage tank 20, pressurized by the pump 21, and then returned to the top of the storage tank 20. The supply pipe 22 for the release agent slurry is branched off from the discharge side pipe of the pump 21 that constitutes the circulation system for external circulation, so that the release agent slurry in a uniform state can be sent to the discharge part 23.

[0034] The discharge part 23 provided at the tip of the supply pipe 22 is preferably a nozzle having, for example, two inlets for introducing the release agent slurry and the dispersion gas, respectively, and one outlet for discharging the release agent slurry dispersed by the dispersion gas. The discharge part 23 is preferably moved unilaterally along the bottom surface of the mold recess 12a of the anode mold 12, which can be realized, for example, by a mechanism shown in FIG. 5. Specifically, one end of a shaft part 33 is supported so as to be freely swingable at the tip of a piston 32 that is extended and retracted from a cylinder 31 by the operation of a servo motor 30, and the discharge part 23 is provided at the other end of the shaft part 33, and the central part of the shaft part 33 in the longitudinal direction is supported by a fixed shaft. This makes it possible to spray the release agent slurry over the entire inner surface of the mold recess 12a by reciprocating the piston 32 with the servo motor 30.

[0035] The dispersion gas introduced into the above-mentioned discharge part 23 is supplied from a dispersion gas supply source 24 such as a compressor or a pressure cylinder through a dispersion gas supply pipe 25. In this way, by directly introducing the release agent slurry and the dispersion gas into the discharge part 23 such as a nozzle, these two-phase fluids are uniformly mixed, and it becomes possible to spray the release agent slurry in a dispersed state. The dispersion gas may be introduced in the middle of the supply pipe 22. In this case, however, there is a risk that the release agent slurry dispersed by the dispersion gas will separate into gas and liquid during the liquid transfer in the supply pipe 22. Therefore, it is preferable to introduce the dispersion gas directly into the discharge part 23 or in the immediate vicinity of it, as described above.

[0036] A cleaning gas supply pipe 27 is connected to the supply pipe 22 of the release agent slurry, which supplies a cleaning gas supplied from a cleaning gas supply source 26 such as a compressor or a pressure cylinder. This allows the release agent slurry remaining in the supply pipe 22 downstream of the connection part of the cleaning gas supply pipe 27 to be pressure-fed by the cleaning gas and discharged from the discharge part 23. It is preferable that the point where the cleaning gas supply pipe 27 is connected to the supply pipe 22 of the release agent slurry is as close as possible to the branch point where the supply pipe 22 branches off from the circulation system where the external circulation is performed. In this case, the distance over which the release agent slurry is pressure-fed by the cleaning gas becomes longer, and the pressure loss of the pipe increases slightly, but it becomes possible to discharge most of the release agent slurry remaining in the supply pipe 22 of the release agent slurry.

[0037] In addition, by making the pressure of the cleaning gas higher than the discharge side pressure of the pump 21, the release agent slurry remaining in the supply pipe 22 upstream of the part where the cleaning gas supply pipe 27 is connected may be pumped to the storage tank 20 through the circulation system in which the external circulation is performed. In addition, although an example in which the dispersion gas supply source 24 and the cleaning gas supply source 26 are provided separately is shown in Fig. 4, they may be integrated into one unit.

[0038] In order to perform the above-mentioned supply and stop of the release agent slurry to the supply pipe 22, the introduction and stop of the dispersion gas which are performed in synchronization with the supply and stop of the release agent slurry, respectively, and the introduction and stop of the cleaning gas which is performed while the spraying of the release agent slurry to the anode mold 12 is stopped, respectively, at predetermined timings, it is preferable to provide automatic valves 22a, 25a, 27a in the supply pipe 22, the dispersion gas supply pipe 25, and the cleaning gas supply pipe 27, respectively, and to control the opening and closing of these valves by a control means 28 such as a CPU. EXAMPLES

[0039] Example 1 Using an anode casting facility as shown in Figure 1, anodes for copper electrolysis were manufactured by repeating the casting process, cooling process, stripping process, and release agent spraying process. In order to investigate the effect of the solid concentration of the release agent slurry on the quality of the anodes for electrolysis, anodes for copper electrolysis were manufactured while varying the solid concentration of clay as a release agent contained in the release agent slurry, and the smoothness of the anode surface and the presence or absence of seizure during casting were evaluated. The amount of release agent slurry sprayed was adjusted so that 72 g of release agent was always supplied to each anode mold with one spray.

[0040] In this Example 1, a release agent slurry supplying device as shown in Fig. 4 was used to spray the release agent slurry, but the piping cleaning process using a cleaning gas was not performed. In addition, a two-fluid nozzle was used for the discharge part 23 of the release agent slurry supplying device, which consisted of a mixing part that mixes the gas phase and the slurry phase introduced from the bottom inlet and the side inlet of the approximately cylindrical tubular part, respectively, and a nozzle tip part with a tip opening that discharges the fluid mixed in the mixing part. Compressed air of 500 kPaG was used as the dispersion gas as the gas phase introduced into this discharge part 23. The above evaluation results are shown in Table 1 below.

[0041] [Table 1]

[0042] As shown in Table 1 above, in the cases of solid content concentrations of 40g / L and 120g / L, casting was possible without any particular problems, and it was found that casting was particularly good in the case of 120g / L. In the case of 40g / L, the amount of moisture was greater than in the other cases, so swelling occurred on the anode surface during initial casting. However, it was found that the occurrence of swelling could be suppressed by ensuring sufficient time for the moisture to evaporate by adjusting the rotation speed of the turntable and the cooling conditions in the cooling process. On the other hand, in the case of 200g / L, the amount of release agent slurry sprayed was significantly smaller than in the other cases, so the release agent slurry could not be sprayed well from the nozzle provided as the release part, and it was difficult to spray uniformly on the inner surface of the anode mold. As a result, seizure occurred in some of the anode molds.

[0043] Example 2 In order to investigate the influence of the introduction of a dispersion gas into the discharge portion 23 on the quality of the electrolytic anode, the release agent slurry was prepared to a solid content concentration of 120 g / L, and the release agent slurry was dispersed by introducing a dispersion gas and the dispersion gas was not introduced. The copper electrolytic anode was manufactured under the same conditions as in Example 1 (no cleaning gas was used). Then, 10 pieces were randomly selected from the electrolytic anode group manufactured in each of the cases where the dispersion gas was introduced and where the dispersion gas was not introduced, and the height and number of blisters were measured. The results are shown in Table 2 (when a dispersion gas was introduced) and Table 3 (when a dispersion gas was not introduced).

[0044] [Table 2]

[0045] [Table 3]

[0046] A t-test was performed on the blister height to compare the results when the above-mentioned dispersion gas was introduced and when it was not introduced, and no significant difference was observed at the 95% level. On the other hand, the number of blisters was significantly reduced at the 95% level when the dispersion gas was introduced. In addition, when the appearance of the anodes with low blister height was observed, the number of blisters was less when the dispersion gas was introduced, even in the case of anodes with similarly low blister heights, and the appearance was finished neatly because the number of blisters was less when the dispersion gas was introduced. From the above results, it was confirmed that the introduction of the dispersion gas can increase the solid concentration of the release agent slurry, and the release agent slurry remaining in the supply pipe can be discharged every time, so that high-quality copper electrolysis anodes with little blistering can be stably manufactured.

[0047] Example 3 A copper electrolytic anode was manufactured under the same conditions as in Example 1, except that a pipe cleaning process was provided in which compressed air of 500 kPaG was introduced into the supply pipe 22 as a cleaning gas in the process following the release agent spraying process, and the release agent slurry remaining in the supply pipe 22 after the release agent spraying process was discharged from the discharge part 23. As a result, the height and number of blisters of the electrolytic anode were similar to those of Example 1 at solid concentrations of 40 g / L, 120 g / L, and 200 g / L, but there was not much individual difference in the operation at each solid concentration, and no extremely large amount of blisters or heights were observed. In addition, the degree of seizure in the case of a solid concentration of 200 g / L was less severe than in Example 1. In this way, by providing the piping cleaning step subsequent to the release agent spraying step, it is possible to always spray a constant amount of release agent slurry at a constant concentration. This makes it possible to further reduce the variation in the time required for the water in the release agent slurry to evaporate for each anode mold. As a result, it is found that swelling and burning are less likely to occur. [Explanation of symbols]

[0048] 10 Anode casting equipment 11. Turntable 12 Anode mold 12a Mold recess 12b Push-up pin 13 Hibe 14 Cooling device 15 Peeling machine 16 Release agent spraying section 20 storage tank 20a Mixer 21 Pump 22 Supply piping 22a Automatic valve 23 Emission part 24 Dispersion gas supply source 25 Dispersion gas supply pipe 25a Automatic valve 26 Cleaning gas supply source 27 Cleaning gas supply piping 27a Automatic valve 28 Control Means 30 Servo motor 31 Cylinder 32 Piston 33 Shaft section A Anode for electrolysis

Claims

1. A method for producing an anode for electrolysis, comprising: a casting step in which molten crude metal is successively cast into a plurality of anode molds provided on an intermittently rotating turntable; a cooling step in which the cast molten crude metal is cooled; a stripping step in which the electrolytic anode solidified by cooling is peeled off from the anode mold; and a release agent spraying step in which a release agent slurry containing clay as a solid content at a solid content concentration of 120 to 160 g / L is sprayed into the anode mold immediately after the electrolytic anode has been peeled off, while being dispersed with a dispersion gas using a release agent spraying part, and the release agent spraying part is caused to scan in one direction along the bottom surface of a mold recess of the anode mold.

2. 2. The method for producing an anode for electrolysis according to claim 1, further comprising a pipe cleaning step of introducing a cleaning gas into a supply pipe for the release agent slurry to discharge the release agent slurry remaining in the supply pipe after the dispersion of the release agent slurry in the release agent spraying step is completed.

3. 3. The method for producing an electrolytic anode according to claim 2, wherein in the pipe cleaning step, the release agent slurry remaining in the supply pipe is also discharged to the supply source side.

4. The method for producing an anode for electrolysis according to claim 1, wherein the release agent slurry is sprayed in an amount of 500 to 3600 mL per square meter of the anode body of the anode for electrolysis.

5. 3. The method for producing an electrolytic anode according to claim 2, wherein a flow rate of the release agent slurry flowing through the supply pipe is variable.

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