JP7358943B2 - Manufacturing method of copper electrolytic anode - Google Patents

Description

The present invention relates to a method for producing a copper electrolytic anode used in an electrolysis step in a non-ferrous smelting process typified by copper smelting.

Conventionally, in the non-ferrous smelting process to obtain valuable metals such as copper from non-ferrous metal raw materials such as sulfide concentrate containing valuable metals such as copper, refining is performed using a refining furnace to increase the purity to 99.8%. An anode is manufactured by casting blister copper, and the resulting anode is sent to an electrolytic process as a copper electrolytic anode.The anode and a separately prepared cathode are alternately inserted into an electrolytic bath and subjected to electrolytic treatment to improve purity. We manufacture electrolytic copper that has improved to over 99.99%.

In electrolytic treatment, a thin stainless steel plate is used in the permanent cathode method (hereinafter referred to as the "PC method"), and a thin seed plate made of high-purity copper is used in the conventional method (seed plate method). As a cathode (hereinafter referred to as "electrolytic cathode"), it is immersed in an electrolytic solution stored in an electrolytic cell alternately with a copper electrolytic anode. Then, by applying a voltage, copper is electrodeposited on the surface of the electrolytic cathode, and the electrodeposited electrolytic copper is peeled off from the thin stainless steel plate to create a product. In the case of a seed plate, it is shipped as a product as it is. are doing.

The copper electrolytic anode used in such electrolytic treatment is cast, for example, with a turntable type casting device. The copper electrolytic anode casting equipment is configured to form a copper electrolytic anode by sequentially performing casting, cooling, and stripping while intermittently rotating an anode mold placed on a turntable. There is.

Specifically, in a copper electrolytic anode casting apparatus, when refined blister copper supplied from a refining furnace is cast into an anode mold, it is cooled and solidified in a cooling section by intermittent rotation on a turntable. Then, the solidified refined blister copper is stripped off from the anode mold by a stripping machine, thereby becoming a copper electrolytic anode.

Now, in the manufacturing process of such a copper electrolytic anode, after the copper electrolytic anode has been stripped off, the anode mold 12 is used to improve the peelability of the copper electrolytic anode from the anode mold before casting the next refined blister copper. For this purpose, a mold release agent (mold release agent slurry) is sprinkled into the mold cavity.

The mold release agent (mold release agent slurry) is also called clay water. For example, as disclosed in Patent Document 1 (see paragraph [0015]), the mold release agent is prepared by mixing 110 g of clay per mold with about 1.8 to 2 liters of water (solid content concentration 0.05 to 0.05 liters). 10 g/cm ³ ) and is evenly distributed over the casting surface of the anode mold.

The surface of the copper electrolytic anode manufactured by such a manufacturing method is required to be smooth. On the other hand, in the electrolysis process, the distance between the anode and cathode is set as narrow as possible to increase productivity, but if there are unnecessary protrusions such as protrusions on the anode surface, the distance between the anode and cathode becomes narrower. This is because, if set, the rate of occurrence of short circuits at the anode will increase, and the current efficiency of the electrolytic process will be significantly deteriorated.

Therefore, Patent Document 2 discloses that copper electrolysis involves performing crystal water decomposition treatment in which the mold release agent containing crystal water is maintained at a temperature higher than the crystal water decomposition temperature before being sprayed onto the anode mold. A method of manufacturing an anode is disclosed. According to the technology disclosed in Patent Document 2, the crystal water contained in the mold release agent is decomposed by the crystal water decomposition treatment, so that it is possible to suppress the formation of blisters on the surface of the copper electrolytic anode during the casting process, and The company says it can improve the surface smoothness of electrolytic anodes. However, since fired clay powder does not have crystallization water, it has poor fixability to the anode mold and wears out the anode mold.

On the other hand, Patent Document 3 discloses a technique related to a method for manufacturing a copper electrolytic anode using a binder such as water glass in order to ensure the fixation to the mold that is lost due to firing. According to the technique disclosed in Patent Document 3, the anode mold and the mold release agent have good fixing properties, and thereby the life of the anode mold can be maintained.

As in the technique disclosed in Patent Document 3, by using a binder such as water glass, the swelling of the surface of the copper electrolytic anode is suppressed and the fixability to the anode mold is improved. Since a binder such as water glass also contains water of crystallization, it is not easy to completely suppress the occurrence of blistering.

Japanese Patent Application Publication No. 2001-191171 Japanese Patent Application Publication No. 2015-139779 Japanese Patent Application Publication No. 2018-065167

An object of the present invention is to provide a method for manufacturing a copper electrolytic anode that suppresses swelling on the surface of the copper electrolytic anode while maintaining fixability to an anode mold.

The present inventors have made extensive studies to solve the above-mentioned problems. As a result, the inventors discovered that the above-mentioned problems could be achieved by using a mold release agent containing crystalline water-containing clay powder and fired clay powder as a mold release agent to be sprayed on the anode mold, leading to the completion of the present invention. . Specifically, the present invention provides the following.

(1) The first aspect of the present invention includes a step of casting a molten crude metal into an anode mold, a step of cooling the molten crude metal cast into the anode mold, and a step of cooling the molten crude metal. A method for producing a copper electrolytic anode, comprising the steps of: stripping off the electrolytic anode; and spraying a mold release agent on the anode mold after the copper electrolytic anode is peeled off, the mold release agent comprising: This is a method for producing a copper electrolytic anode, which includes clay powder containing crystal water and fired clay powder.

(2) A second aspect of the present invention is that in the first aspect, the calcined clay powder in the mold release agent has a mass of 60 to 80% based on the total mass of the crystal water-containing clay powder and the calcined clay powder. % of copper electrolytic anode manufacturing method.

(3) In the third aspect of the present invention, in the first or second aspect, the fired clay powder is a crystalline water-containing clay powder that contains crystallized water, and the crystallized water is measured by differential thermal-thermogravimetric analysis. This is a method for producing a copper electrolytic anode obtained by performing a crystal water decomposition treatment held at a temperature higher than the decomposition temperature of .

(4) The fourth aspect of the present invention is that in any one of the first to third aspects, the amount of the release agent to be sprayed per 1 m ² of the anode mold [weight of release agent (g)/weight of the anode mold] This is a method for producing a copper electrolytic anode, in which the sprayed area (m ² )] is set to 80 (g/m ² ) or more and 180 (g/m ² ) or less.

(5) The fifth aspect of the present invention is the copper electrolytic solution according to any one of the first to fourth aspects, wherein the solid content concentration of the mold release agent is 0.05 g/cm ³ or more and 0.10 g/cm ³ or less. This is an anode manufacturing method.

According to the present invention, it is possible to effectively suppress swelling on the surface of the copper electrolytic anode while fixing a mold release agent to the anode mold and maintaining good peeling of the copper electrolytic anode.

1 is a schematic diagram schematically showing the configuration of a copper electrolytic anode casting apparatus used in a method for manufacturing a copper electrolytic anode. FIG. 3 is an explanatory diagram of a copper electrolytic anode stripping operation using a push-up pin. (a) A plan view schematically showing a copper electrolytic anode in which a bulge has occurred. (b) A cross-sectional view taken along the line XX of the copper electrolytic anode. 1 is a graph showing the swelling height of copper electrolytic anodes manufactured using mold release agents 1 and 2 and the rate of swelling thereof.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments, and various changes can be made without changing the gist of the present invention. Furthermore, in this specification, the expression "X to Y" (X and Y are arbitrary numerical values) means "more than or equal to X and less than or equal to Y."

≪1. Copper electrolysis anode manufacturing method≫
The copper electrolytic anode manufacturing method according to the present invention is a method for manufacturing an anode used in electrolytic treatment, which is carried out using a copper electrolytic anode casting apparatus. Specifically, the method for producing this copper electrolytic anode includes a step of casting molten crude metal into an anode mold, a step of cooling the molten crude metal cast into the anode mold, and a step of casting copper made of the cooled molten crude metal. The method includes a step of stripping off the electrolytic anode, and a step of spraying a mold release agent onto the anode mold after the copper electrolytic anode is stripped off.

This copper electrolytic anode manufacturing method is characterized in that the mold release agent used in the step of spraying the mold release agent onto the anode mold contains crystal water-containing clay powder and calcined clay powder. It is said that

According to such a method, it is possible to effectively suppress swelling on the surface of the produced copper electrolytic anode while fixing the mold release agent to the anode mold and maintaining good peeling of the copper electrolytic anode. .

<1-1. About electrolytic anode casting equipment＞
Here, as described above, the method for manufacturing a copper electrolytic anode according to the present invention can be carried out in a copper electrolytic anode casting apparatus. Here, prior to explaining the method for manufacturing a copper electrolytic anode, a copper electrolytic anode casting apparatus for casting a copper electrolytic anode will be explained.

FIG. 1 is a diagram showing an example of the configuration of a copper electrolytic anode casting apparatus. As shown in FIG. 1, the copper electrolytic anode casting apparatus 10 includes a turntable 11, an anode mold 12, a cooling section 13, a defective anode stripping machine 14, a stripping machine 15, a mold release agent dispersing section 16, and the like. The copper electrolytic anode casting apparatus 10 is connected to a refining furnace 17 that is a source of refined blister copper in a molten state.

In the copper electrolytic anode casting apparatus 10, a turntable 11 is installed to be able to rotate intermittently in the direction of arrow R in FIG. 1, and a plurality of anode molds 12 are placed on the turntable 11. . Refined blister copper in a molten state is poured into the anode mold 12 and cast.

In the copper electrolytic anode casting apparatus 10, the cooling unit 13 cools the purified blister copper cast into the anode mold 12, and the stripping machine 15 strips the cooled and solidified copper electrolytic anode from the anode mold 12. take. Then, the mold release agent spraying section 16 sprays a mold release agent into the anode mold 12 to improve releasability during stripping.

In such a copper electrolytic anode casting apparatus 10, a plurality of anode molds 12 placed on a turntable 11 are intermittently rotated in the direction of arrow R, thereby performing a casting process, a cooling process, and a peeling process. The mold release agent dispersion process is performed sequentially.

<1-2. About each process>
The method for manufacturing a copper electrolytic anode according to the present invention includes repeatedly performing a casting process, a cooling process, a stripping process, and a release agent dispersing process, the details of which will be explained below, in the copper electrolytic anode casting apparatus 10. Casting a copper electrolytic anode.

[Casting process]
The casting process is a process of casting refined blister copper into the anode mold 12. In this step, a fixed amount of refined blister copper supplied from the refining furnace 17 is poured into the mold recess of the anode mold 12, thereby casting the refined blister copper into the shape of a copper electrolytic anode.

[Cooling process]
The cooling step is a step of cooling the refined blister copper cast into the mold recess of the anode mold 12. In this step, solidification of the refined blister copper is promoted in the cooling section (cooling hood) 13 by means of spraying cooling water onto the cast refined blister copper. Furthermore, in this step, the temperature of the anode mold 12 is also cooled down to an appropriate temperature.

The inside of the cooling unit (cooling hood) 13 is configured by spraying cooling water, for example in the form of a shower, onto the copper electrolytic anode and the anode mold 12 .

[Peeling process]
The stripping step is a step of stripping off the copper electrolytic anode that has been cooled and solidified in the cooling step from the mold recess of the anode mold 12.

FIG. 2 shows a schematic diagram of the copper electrolytic anode stripping operation. As a method for stripping off the copper electrolytic anode E, for example, an ear portion (hanging ear portion) that is a part of the copper electrolytic anode E is pushed up from the mold recess using a push-up pin that has been previously installed in the mold recess. This can be done by hooking the part with the peeling machine 15 and peeling it off.

Moreover, this pushing up is preferably performed within the cooling section (cooling hood) 13. For example, the first push-up (primary push-up) is performed at approximately the midpoint in the direction of travel in the cooling hood (for example, point M in FIG. 1), and at the downstream side in the direction of travel in the cooling hood (for example, point D in FIG. 1). Perform the second push up (secondary push up).

The first push-up (primary push-up) is preferably performed in a state where the copper electrolytic anode is solidified to the extent that it can withstand the load due to push-up, that is, does not deform. Specifically, it is preferable to perform the first push-up (primary push-up) when the mold temperature becomes 700° C. or lower. If the mold temperature is too high, the copper electrolytic anode that is in the middle of solidification will succumb to the pushing force of the push-up pin 18 and bend downward into a convex state, resulting in the bent defective anode E' shown by the dotted line in FIG. This is because there is a risk that Note that such a defective anode E' is removed by a defective anode stripping machine 14 shown in FIG.

The second push-up (secondary push-up) is performed in a state where the mold temperature is lower than that of the first push-up. In this manner, by pushing up twice or more at different temperatures within the cooling section (cooling hood) 13, the copper electrolytic anode can be smoothly peeled off from the mold recess of the anode mold 12. Such a push-up position can be adjusted to some extent within the cooling section (cooling hood) 13 so that the push-up position can be pushed up twice or more at different temperatures.

[Releasing agent spraying process]
The mold release agent spraying step is a step of spraying a mold release agent into the mold recess of the anode mold 12 after the copper electrolytic anode has been peeled off. After the copper electrolytic anode is peeled off in the above-mentioned stripping process, in order to carry out the next casting process in a preferable manner, a mold release agent is sprayed into the recessed part of the anode mold 12, and as will be described later, the temperature is 170 to 180°C. Moisture contained in the mold release agent is evaporated by the anode mold 12 having a certain level of heat, and a mold release layer is formed. The anode mold 12 on which the mold release layer has been formed is transported to a casting position for refined blister copper in order to perform the next cycle of casting process, and then new refined blister copper is cast therein.

≪2. About mold release agent≫
Here, the mold release agent sprayed onto the anode mold 12 in the mold release agent spraying step is used as a slurry formed by mixing crystal water-containing clay powder, fired clay powder, and water. The method for manufacturing a copper electrolytic anode according to the present embodiment is characterized by using a mold release agent containing crystal water-containing clay powder and calcined clay powder.

Here, if a mold release agent consisting only of clay powder containing crystallized water is used as in the past, blisters like those shown in Figures 3(a) and (b) may appear on the surface of the anode surface body. In some cases, irregularities (hereinafter referred to as "bulges") S are formed. The cause of the "swelling" that occurs on the surface of such a copper electrolytic anode is considered to be as follows. In other words, since the temperature of the anode mold 12 during spraying of the mold release agent is about 170 to 180°C, the adhering water of the water contained in the mold release agent (mold release agent slurry) evaporates, but the adhering water does not melt into the clay powder. The crystallization water contained remains undecomposed and remains until the next casting process. Then, when refined blister copper is poured into the anode mold 12 to which clay powder with residual crystallization water is attached, the residual crystallized water is decomposed by the heat of the refined blister copper, generating steam. When the generated water vapor is taken into the vicinity of the surface of the molten copper, solidification of the surface of the molten copper progresses in this state, and as a result, blisters are formed on the surface.

Therefore, in the method for manufacturing a copper electrolytic anode according to the present embodiment, the mold release agent is fixed to the anode mold 12 by using a mold release agent containing crystal water-containing clay powder and fired clay powder. While maintaining good peeling of the copper electrolytic anode, it is possible to effectively suppress swelling on the surface of the produced copper electrolytic anode.

(1) Composition of mold release agent (clay powder containing crystal water)
Crystal water-containing clay powder is clay powder containing crystal water. By containing the crystallized water-containing clay powder in the mold release agent, the crystallized water-containing clay powder is rapidly dried by the anode mold 12 in a high temperature state and becomes a binder, fixing the mold release agent to the anode mold 12. A good release layer is formed in the anode mold 12 to facilitate peeling off the copper electrolytic anode from the anode mold 12.

The clay powder in the crystal water-containing clay powder is not particularly limited, but includes, for example, one or more minerals such as kaolinite, halloysite, montmorillonite, illite, and vermiculite as a main component.

Further, the upper limit of the particle size _D50 of the clay powder is preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 9 μm or less. In addition, "particle size _D50 " is a particle size which becomes 50% of volume integration in a particle size distribution curve, and can be measured by a laser diffraction scattering type particle size distribution measuring method.

If the particle size D ₅₀ of the clay powder containing crystal water exceeds 15 μm, the strength of the release layer formed on the anode mold 12 may decrease, and the fixation of the release agent to the anode mold may decrease.

The lower limit of the particle size _D50 of the clay powder is not particularly limited, but is preferably 1 μm or more, more preferably 4 μm or more, and even more preferably 5 μm or more.

(fired clay powder)
Calcined clay powder is clay powder obtained by firing clay powder containing crystallized water. In this way, by including the fired clay powder in the mold release agent, swelling on the surface of the copper electrolytic anode can be suppressed.

The fired clay powder is obtained by firing the clay powder containing crystal water while maintaining it at a predetermined temperature or higher. More specifically, the fired clay powder is subjected to crystal water decomposition treatment in which the crystal water-containing clay powder containing crystal water is held at a temperature equal to or higher than the crystal water decomposition temperature measured by differential thermal thermogravimetric analysis. It can be obtained by In this way, fired clay powder is obtained by firing clay powder containing crystal water, which together with the fired clay powder constitutes a mold release agent, as a raw material. By performing baking to obtain fired clay powder, it is not necessary to obtain crystal water-containing clay powder and fired clay powder separately, and productivity can be improved.

In the crystal water decomposition treatment, the crystal water decomposition temperature is the decomposition temperature determined by differential thermal-thermogravimetric analysis. Specifically, the decomposition temperature of water of crystallization by differential thermal-thermogravimetric analysis can be measured by a measuring method according to JIS K0129. Note that the decomposition temperature of this crystal water varies due to the measurement equipment and the measurement method when it is measured by a method other than differential thermal-thermogravimetric analysis. It is preferable to maintain the temperature at about 5% lower than the decomposition temperature of crystal water measured by.

Further, during the crystal water decomposition treatment, it is preferable that the temperature higher than the crystal water decomposition temperature is equal to or lower than the crystal water decomposition temperature +300°C. By setting the decomposition temperature of crystallization water to +300° C. or lower, sintering of the clay powder can be suppressed and the particle size can be easily controlled.

Further, for the crystal water decomposition treatment, various existing heating furnaces in the same plant, such as an electric furnace or a kiln, can be used, for example. However, it is not essential that this treatment be performed in a series of processes or within the same equipment.

Further, the firing time is preferably 10 to 120 minutes. If the holding time for firing is less than 10 minutes, the firing may be insufficient and crystallization water may remain in the clay powder. On the other hand, if the holding time for calcination exceeds 120 minutes, although the crystal water can be completely decomposed, it is not preferable because the energy cost will be excessive.

(Ratio of clay powder containing crystallized water to fired clay powder)
As described above, by using a mold release agent containing crystal water-containing clay powder and fired clay powder, the copper electrolytic anode is manufactured while maintaining the fixation of the mold release agent to the anode mold 12. Surface swelling can be effectively suppressed. That is, a copper electrolytic anode with suppressed surface swelling can be manufactured with high productivity by combining the effects of the crystallized water-containing clay powder and the fired clay powder.

Here, the content ratio of the crystal water-containing clay powder and the fired clay powder is not particularly limited, but it is preferable that the content of the fired clay powder is greater than the content of the crystal water-containing clay powder. More specifically, for example, the content of the fired clay powder in the mold release agent is preferably within the range of 60 to 80% by mass based on the total mass of the crystal water-containing clay powder and the fired clay powder. . If the amount of baked clay powder added exceeds 80% by mass, the content of crystallized water-containing clay powder will be relatively reduced, so there is a risk that the fixability to the anode mold 12 will be reduced. Furthermore, the mold release layer becomes thicker, which may result in insufficient cooling of the copper electrolytic anode. On the other hand, if the amount of calcined clay powder added is less than 60% by mass, the content of calcined clay powder will be relatively reduced, so there is a risk that the effect of suppressing swelling on the surface of the copper electrolytic anode will not be sufficiently obtained. be. Furthermore, the mold release layer becomes thinner, and the anode mold 12 may be worn out.

(solid content concentration of mold release agent)
Further, the solid content concentration in the mold release agent is not particularly limited, but is preferably 0.05 g/cm ³ or more and 0.10 g/cm ³ or less.

If the solid content concentration of the mold release agent slurry is less than 0.05 g/cm ³ , the mold release layer formed on the anode mold 12 tends to be thin, and there is a possibility that fixing performance may be reduced. Furthermore, if the amount of the release agent to be sprayed is increased in order to improve the fixability to the anode mold 12, it will take too much time to spray the mold release agent per anode mold. Moreover, if it is larger than 0.10 g/cm ³ , the mold release layer formed on the anode mold 12 tends to become thick, and there is a possibility that cooling of the copper electrolytic anode may become insufficient. In addition, in the mold release agent dispersion process using a mold release agent containing crystal water-containing clay powder and fired clay powder, depending on the method of spraying, the release agent may not be able to evaporate in time for the water to evaporate, and the mold release agent may not be uniformly applied to the mold recesses. It may be difficult to spray.

(2) Spraying amount of mold release agent In the present invention, the amount of mold release agent sprayed in the mold release agent spraying step is not particularly limited, but the amount of mold release agent sprayed per 1 m ² of anode mold [ Release agent weight (g)/dispersed area of anode mold (m ² )] is preferably 80 (g/m ² ) or more and 180 (g/m ² ) or less.

If the amount of the above-mentioned mold release agent to be sprayed is less than 80 g/m ² , the mold release layer formed on the anode mold 12 tends to become thin, and there is a possibility that the fixing property to the anode mold 12 may deteriorate. On the other hand, if the amount of the mold release agent to be sprayed exceeds 180 g/m ² , the mold release layer formed on the anode mold 12 tends to become thick, and there is a possibility that cooling of the copper electrolytic anode may become insufficient.

In addition, in the mold release agent spraying step, it is preferable to dry the mold release agent after spraying the slurry of the mold release agent into the mold recesses of the anode mold 12 and before casting refined blister copper into the mold recesses in the next cycle. . Specifically, water contained in the mold release agent evaporates to form a mold release layer made of solids contained in the mold release agent, and the next cycle of casting process is performed.

At this time, the temperature of the anode mold 12 is approximately 170 to 180° C., and the heat causes the moisture contained in the mold release agent to evaporate. Therefore, in order to dry the mold release agent, the anode mold 12 may be left standing for a predetermined period of time, and air may be blown if necessary.

When the anode mold 12 is left still, the time for leaving it still (drying time) is preferably about 60 to 160 seconds. If the standing time (drying time) is shorter than 60 seconds, there is a risk that moisture may remain in the sprayed mold release agent, while on the other hand, if the standing time (drying time) exceeds 160 seconds, There is a possibility that the production amount of copper electrolytic anodes will decrease.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1]
(Manufacture of fired clay powder)
The decomposition temperature of the crystallized water contained in the crystallized water-containing clay powder prepared as a mold release agent was 647° C. as measured by differential thermal-thermogravimetric analysis according to JIS KO129. Therefore, this clay powder containing crystal water was subjected to crystal water decomposition treatment by holding it at 700° C. for 500 minutes to obtain fired clay powder. The amount of decomposed crystal water was 9% by mass based on the mass of the crystal water-containing clay powder. When the particle size D ₅₀ of this fired clay powder was measured, it was found that the particle size D ₅₀ =15 μm, which was coarser than the crystal water-containing clay powder before treatment.

Next, the fired clay powder was ground to a particle size D ₅₀ =10 μm using a ball mill. The particle size _D50 was measured using a laser diffraction scattering particle size distribution analyzer (manufactured by Macrotrack Co., Ltd., Model No. 9320-X100).

(Preparation of mold release agent)
Crystallized water-containing clay powder and fired clay powder are suspended in water, and a mold release agent (solid content concentration of 0.02 g/cm ³ for the crystallized water-containing clay powder and 0.04 g/cm ³ for the fired clay powder) is added. 06g/cm ³ ) was prepared. Incidentally, the amount of the fired clay powder was 66% by mass based on the total mass of the crystallized water-containing clay powder and the fired clay powder.

(Manufacture of copper electrolytic anode)
The amount of the release agent to be sprayed per 1 m ² of the anode mold [release agent weight (g)/sprayed area of the anode mold (m ² )] of the mold release agent obtained as described above is 110 (g). / m ² ), and the anode mold is left standing at a temperature of about 170 to 180°C for 90 seconds to dry, forming a release layer. After passing through the process, a copper electrolytic anode was manufactured through the above-mentioned casting process, cooling process, and peeling process.

For the 40 produced copper electrolytic anodes, the maximum value of the swelling height on the surface of each copper electrolytic anode was measured, and the average value was as low as 3.6 mm, indicating that swelling could be effectively suppressed. In addition, over 100 copper electrolytic anodes could be manufactured until the mold reached the end of its life due to wear and tear. Note that the "bulge height" of the surface of the copper electrolytic anode means the height from the surface of the copper electrolytic anode to the top of the bulge.

[Example 2]
Regarding the mold release agent, a crystal water-containing clay powder and a calcined clay powder were suspended in water, and a mold release agent was prepared in which the crystal water-containing clay powder was 0.03 g/cm ³ and the calcined clay powder was 0.04 g/cm ³ . A copper electrolytic anode was produced in the same manner as in Example 1, except that the solid content concentration was 0.07 g/cm ³ ). Incidentally, the amount of the fired clay powder was 57% by mass based on the total mass of the crystallized water-containing clay powder and the fired clay powder. The amount of the release agent sprayed per 1 m ² of the anode mold [weight of release agent (g)/spread area of the anode mold (m ² )] was 127 (g/m ² ).

When the swelling height of 40 copper electrolytic anodes was measured, the average value was as low as 6.4 mm. They were able to manufacture more than 100 copper electrolytic anodes until the mold reached the end of its life due to wear and tear.

[Comparative example 1]
Regarding the mold release agent, only the crystal water-containing clay powder was suspended in water, and the mold release agent was prepared so that the crystal water-containing clay powder was 40 g/L (solid concentration 0.04 g/cm ³ ). A copper electrolytic anode was manufactured in the same manner as in Example 1. The amount of the release agent sprayed per m ² of the anode mold [weight of release agent (g)/spread area of the anode mold (m ² )] was 73 (g/m ² ).

When the swell height of 83 copper electrolytic anodes was measured, the average value was 7.4 mm, and the swell was larger than in the example, and the swell could not be suppressed effectively. It should be noted that more than 4,000 copper electrolytic anodes could be manufactured until the anode mold reached the end of its life due to wear and tear.

[Comparative example 2]
Regarding the mold release agent, only the fired clay powder was suspended in water and the mold release agent was prepared so that the fired clay powder was 40 g/L (solid content concentration 0.04 g/cm ³ ). A copper electrolytic anode was manufactured in the same manner.

The release agent peeled off and caused burn-in, making it impossible to produce a copper electrolytic anode.

From the above, the copper electrolytic anode production method of the present invention, in which a mold release agent containing crystallized water-containing clay powder and calcined clay powder is sprayed on an anode mold, fixes the mold release agent to the mold while maintaining the anode surface. It was confirmed that swelling can be suppressed.

[Reference example]
Regarding the mold release agent, fired clay powder and water glass were suspended in water, 0.04 g/cm ³ of fired clay powder and 0.04 mL/g of water glass (sodium silicate specified in JIS K1408, No. 3). Mold release agent 2 was prepared as follows.

Forty pieces of copper electrolytic anodes were each manufactured in the same manner as in Example 1 using Mold Release Agent 1 (Example 1) containing crystal water-containing clay powder and calcined clay powder and Mold Release Agent 2. The amount of spraying was made to be the same as that of Example 1. FIG. 4 shows the height of blistering on the surface of copper electrolytic anodes manufactured using mold release agents 1 and 2 and the rate of blistering. Note that the "bulge height" of the surface of the copper electrolytic anode means the height from the surface of the copper electrolytic anode to the top of the bulge.

Compared to the case where mold release agent 2 containing water glass and fired clay powder is used, when mold release agent 1 containing crystallized water-containing clay powder and fired clay powder is used, the height is 6 to 6. The rate of occurrence of 8 mm bulges was reduced. This is because in the case of mold release agent 2 containing water glass, the drying time is longer and it takes time for the mold release agent in the anode mold to dry between castings, so the crystallization water is not completely decomposed. It is presumed that this is because the swelling on the surface of the copper electrolytic anode could not be sufficiently suppressed.

Therefore, it can be seen that by containing crystal water-containing clay powder in the mold release agent, swelling on the surface of the copper electrolytic anode can be suppressed more effectively than when the mold release agent contains water glass.

10 Copper electrolytic anode casting device 11 Turntable 12 Anode mold 13 Cooling unit 14 Defective anode stripping machine 15 Stripping machine 16 Release agent spraying unit 17 Refining furnace 18 Push-up pin E Anode for electrode E' Anode for electrode (defective anode )
S bulge

Claims (4)

a step of casting molten crude metal into an anode mold;
cooling the molten crude metal cast into the anode mold;
stripping off the copper electrolytic anode made of the cooled molten crude metal;
A method for producing a copper electrolytic anode, comprising the step of spraying a release agent on the anode mold after the copper electrolytic anode is stripped off,
The mold release agent contains crystal water-containing clay powder and fired clay powder ,
The fired clay powder is obtained by subjecting crystal water-containing clay powder containing crystal water to a crystal water decomposition treatment in which the crystal water-containing clay powder is held at a temperature equal to or higher than the crystal water decomposition temperature measured by differential thermal - thermogravimetric analysis. ,
The particle size D50 of the crystal water-containing clay powder is 15 μm or less.
Copper electrolytic anode manufacturing method. The copper electrolytic anode according to claim 1, wherein the calcined clay powder in the mold release agent is contained within a range of 60 to 80% by mass based on the total mass of the crystal water-containing clay powder and the calcined clay powder. Production method. The amount of the release agent to be sprayed per 1 m ² of the anode mold [release agent weight (g)/sprayed area of the anode mold (m ² )] is 80 (g/m ² ) or more and 180 (g/m ^{2 )} . ) The method for producing a copper electrolytic anode according to claim 1 or 2 . The copper electrolytic anode manufacturing method according to any one of claims 1 to 3 , wherein the solid content concentration of the mold release agent is 0.05 g/cm ³ or more and 0.10 g/cm ³ or less.

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