JP5594602B2 - Anode casting apparatus for rotary copper electrolysis and crack control method for peripheral edge of copper electrolysis anode - Google Patents

Description

The present invention relates to a rotary copper electrolysis anode casting apparatus for casting refined crude copper produced in a copper smelting process and supplying it as an anode to the next electrolytic refining process, and a crack suppression method for the peripheral edge of the copper electrolysis anode. The present invention relates to the type of mold release agent in the casting apparatus and the spraying method.

The anode for copper electrolysis is usually cast in a shape having a pair of hanging ears on both sides of the top of the main body. The anode for copper electrolysis is manufactured by a copper anode rotary casting machine.
As a typical copper anode rotary casting machine, a certain amount of molten copper discharged from a copper refining furnace is placed on a number of copper molds placed on one or more turntables that rotate intermittently. After casting and solidifying by cooling, the copper anode is peeled off from the mold, and the obtained copper anode is supplied to the electrolysis process.

In casting this type of anode for copper electrolysis, molten copper at 1100 ° C. to 1150 ° C. is poured into each mold while a pair of turntables on which the mold is placed are intermittently rotated in opposite directions. The operation of removing the anode cooled or solidified at other block positions from the mold is performed at the same time.
In this apparatus, as a preparatory work for performing the next casting after stripping the copper anode from the mold, for example, Patent Document 1 discloses a mold release agent such as clay and ends of the upper and lower sides of the mold at the center of the mold. A technique for applying silicon oil to prevent the occurrence of casting on the part is disclosed. In addition to clay, release agents such as barium sulfate are known.

  In this way, the shape of the anode is adjusted, that is, the anode bending that occurs when peeling from the mold, the unevenness that occurs on the anode surface, the casting that occurs at the end during casting of the anode (casting of molten metal), and the like are suppressed. Is important for performing good operation in the electrolysis process, which is a subsequent process.

  By the way, a crack may occur on the anode side surface after casting as a defect of the anode shape. Usually, if the depth is about 1/3 or less of the anode thickness, there will be no effect on the subsequent electrolysis process, but if a crack larger than this occurs, it will be at the end of the electrolysis process for the anode. As the anode is thinned and thinned by electrolysis, the cracks rapidly develop and structurally break down, and the normal posture (suspended state) cannot be maintained in the electrolytic cell. Problems such as dropping into the tank occur and adversely affect the electrolysis process, but it has been difficult to cope with the conventional technique.

JP 2001-191171 A

Not only in the solidification process of the anode but usually in the casting process, there is a difference in cooling rate between the central part and the peripheral part of the mold. That is, the central part does not cool easily, and therefore the cooling rate is low, whereas the peripheral part has a high cooling rate.
For this reason, even in the casting process of the anode, uneven stress distribution occurs during the solidification process depending on the position of the mold, and particularly at the peripheral part, the cooling rate is high and stress is concentrated, so cracks occur, and the above-mentioned problems occur. Occur.

  Of course, a countermeasure corresponding only to the reduction of cracks is not sufficient, and a countermeasure capable of simultaneously suppressing, for example, casting is required. Moreover, the solution by installing new equipment such as heat insulation equipment is desirable because it tends to increase the investment cost or decrease the work efficiency by adjusting the cooling efficiency and changing the work time, leading to a decrease in productivity and competitiveness. Absent.

From the above, the present invention mitigates the uneven cooling rate in the copper anode at the center and periphery of the mold during casting of the anode, suppresses cracks in the periphery of the anode, and does not deteriorate casting. An object of the present invention is to provide a method for suppressing cracks in an anode for copper electrolysis and a casting apparatus, which are low in cost.

The present inventors have found that the above problems can be solved by paying attention to the thermal conductivity of the release agent and the spraying method, and have completed the present invention.
That is, according to the first aspect of the present invention, when casting a copper electrolysis anode having a pair of hanging ears on both sides of the top of the main body into a mold on a turntable that rotates intermittently, the turntable At the upper release agent spraying position, a release agent having a higher thermal conductivity than barium sulfate (hereinafter sometimes referred to as release agent a) is applied to the center of the casting mold, and from the release agent a. A crack inhibiting method for a copper electrolysis anode peripheral portion , characterized in that a crack preventing mold release agent having a low thermal conductivity is sprayed on the peripheral portion of a casting mold.

In the second invention of the present invention, a release agent (release agent a) having a higher thermal conductivity than that of barium sulfate in the first invention is sprayed on the center of the mold, and then the thermal conductivity is higher than that of the release agent a. A method for suppressing cracks in the peripheral edge of an anode for copper electrolysis, characterized in that a low release agent for crack prevention is sprayed on the peripheral edge of a mold.

According to a third aspect of the present invention, the crack preventing release agent having a thermal conductivity lower than that of the release agent having a high thermal conductivity (release agent a) in the first and second inventions is barium sulfate. It is the crack suppression method of the anode peripheral part for copper electrolysis characterized.

According to a fourth aspect of the present invention, there is provided a rotary copper electrolysis anode casting apparatus for casting a copper electrolysis anode having a pair of drooping ears on both sides of the top of a copper electrolysis anode body using a mold. A mold release agent spraying facility and a crack prevention mold release agent spraying facility are provided at the same stop position on the turntable that intermittently rotates and moves, and cracks with lower thermal conductivity than the mold release agent a at the periphery of the mold A rotating copper electrolysis anode casting apparatus comprising a nozzle for spraying a release agent for prevention.

  According to the present invention, when the release agent a such as clay having higher thermal conductivity than the release agent for crack prevention and the nozzle of the release agent for crack prevention such as barium sulfate are installed at the same block position, It is possible to control the cracking of the anode and solve problems such as dropping the anode in the copper electrolysis process without making major modifications to the equipment such as nozzles and hoods, and without worsening the occurrence of casting. Because it can, its industrial value is extremely large.

It is the schematic which shows the anode casting_mold | template of this invention, and a mold release agent spray nozzle position. It is the schematic which shows the anode mold | type of a prior art, and a mold release agent spray nozzle position. It is a figure which shows the time table of the mold release agent application in an Example.

  The present inventors have observed the anode casting process and temperature distribution as well as the various causes of cracking of the anode, and examined the various causes. It is easy to concentrate on the periphery, especially when the stress increases, and by using a release agent such as barium sulfate with low thermal conductivity for crack prevention only in that part, the occurrence of casting is worsened It has been found that cracks can be suppressed without causing them to occur.

That is, in the casting apparatus of the present invention, the type of mold release agent is changed on the bottom and side surfaces, and the spray nozzle is installed in a hood provided in the same block, which solves the problems in the prior art. .
Cracking of release agent a such as clay water and barium sulfate when spraying release agent a such as clay water and cracking release agent such as barium sulfate at the same stop position on the turntable in the present invention The spraying position of the mold release agent for prevention with respect to the mold will be described with reference to FIG.

1 is sprayed with a release agent a such as clay water having a higher thermal conductivity than that of the crack preventing release agent, and the hatched portion B has a thermal conductivity higher than that of the release agent a such as barium sulfate. Apply low release agent for crack prevention.
That is, in FIG. 1, the nozzle is arranged so that the nozzle tip for the release agent a such as clay is located at the center of the mold 1. On the other hand, the nozzle is arranged so that the tip of the spray nozzle of the crack preventing release agent such as barium sulfate is located in the peripheral portion.
For example, in FIG. 1, a release agent a such as clay may be disposed at a mark “◯”, and a spray nozzle of a release agent for crack prevention such as barium sulfate may be disposed at a mark “Δ”.

  The order of spraying the release agent in the present invention is that the mold is placed on the spray block provided with the spray nozzle for the release agent a such as clay and the spray nozzle for the release agent for crack prevention such as barium sulfate, or just before stopping. First, the mold release agent a is sprayed, and the crack preventing mold release agent is sprayed just before the mold starts moving to the next block.

Further, in order to sufficiently bring out the effects of the present invention, when clay is used for the release agent a having a higher thermal conductivity than barium sulfate, 105 to 115 g of clay per mold is 1.1 to 1.5. Disperse clay water suspended in 1 liter of water over the center of the mold. Further, when barium sulfate is used as a crack preventing mold release agent having a lower thermal conductivity than the mold release agent a, 145 to 155 g of barium sulfate per one mold is suspended in 0.7 to 0.8 liter of water. It is preferable to spray the solution on a predetermined part of the mold. Each of the above ranges of concentration and amount is suitable for spreading to an appropriate range on the mold surface after spraying and for sufficient evaporation of moisture.
Hereinafter, the present invention will be described in detail using examples.

Each block is rotated according to the timetable shown in FIG. 3 using a turntable operated in a cycle of intermittently rotating one block in 12 to 13 seconds and stopping in a spraying block at a fixed position for 12 to 13 seconds. The agent was sprayed.
That is, the release agent a is for 11 to 12 seconds after the mold on the turntable starts rotating from the previous block, that is, for preventing cracking of the release agent a such as clay and barium sulfate. Immediately before stopping at the spraying block provided with the nozzle for spraying the release agent, spraying of the release agent a such as clay was started from the nozzle for spraying the release agent and sprayed for about 5 to 6 seconds.

Next, barium sulfate as a crack preventing mold release agent is 21 to 22 seconds after the start of rotation of the turntable from the previous block, that is, 8 to 9 seconds after stopping at the spraying block. It sprayed for about 2-3 seconds from the nozzle for spraying.
The used spraying nozzles are arranged as shown in FIG. That is, the clay water of the release agent a was sprayed from the position indicated by “◯” in FIG. 1 and barium sulfate for crack prevention was sprayed from the position indicated by “Δ”.
As for the clay water of the mold release agent a, 110 g of clay per mold is suspended in 1.3 liters of water and sprayed on the center of the mold, and barium sulfate, which is a mold release agent for preventing cracks, is used as the mold. Each sheet was suspended in 0.75 liters of water at 150 g and spread on the side surface of the mold.

  After casting in this manner, a total of 200 copper anodes were taken out from each of 20 different casting lots, and a total amount of cracks was measured for each copper anode. The values are shown in Table 1 below.

(Comparative Example 1)
A turntable similar to that of Example 1 was used except that silicon oil (diluted with water at a concentration of 10% by weight) was sprayed as a release agent from the position indicated by “Δ” in FIG. Casting was performed under the same spraying conditions.
Similarly to Example 1, 20 cracks obtained from 10 different casting lots were measured for a total of 200 copper anodes, and the average value of the results is shown in Table 1.

(Comparative Example 2)
A turntable similar to that in Example 1 was used except that clay water was sprayed as a release agent from the position “◯” shown in FIG. 2, and barium sulfate was sprayed as a release agent from the position indicated by “●”. Casting was performed under the same spraying conditions as in Example 1.
Similarly to Example 1, 20 cracks obtained from 10 different casting lots were measured for a total of 200 copper anodes, and the average value of the results is shown in Table 1.

  As is clear from Table 1, the amount of crack generation in Example 1 is greatly reduced compared to Comparative Examples 1 and 2, and the effect of suppressing cracks can be obtained without deteriorating casting. I understand.

Claims (4)

When a copper electrolysis anode having a pair of hanging ears on both sides of the top of the main body is cast using a mold on a turntable that rotates intermittently, barium sulfate at the release agent spraying position on the turntable The mold release agent a having a higher thermal conductivity is sprayed on the center of the mold, and the crack release agent having a thermal conductivity lower than that of the mold release agent a is sprayed on the peripheral edge of the mold. A method for suppressing cracks in the peripheral edge of an anode for copper electrolysis. A mold release agent a having a thermal conductivity higher than that of barium sulfate is sprayed on the center of the mold, and then a crack release agent having a thermal conductivity lower than that of the mold release agent a is sprayed on the periphery of the mold. The crack suppression method of the anode peripheral part for copper electrolysis of Claim 1 characterized by the above-mentioned. 3. The method for suppressing cracks in a peripheral portion of an anode for copper electrolysis according to claim 1, wherein the release agent for preventing cracking having a thermal conductivity lower than that of the release agent a is barium sulfate. The anode copper electrolysis with a pair of depending lugs on both sides top of the anode body for copper electrolyte, the anode Casting device for rotating copper electrolyte is cast using a mold,
At the same stop position on the turntable that rotates the mold intermittently, the mold release agent spraying equipment and the crack prevention mold release agent spraying equipment are provided,
An anode casting apparatus for rotary copper electrolysis, comprising a nozzle for spraying a crack preventing mold release agent having a thermal conductivity lower than that of the mold release agent a at a peripheral portion of the mold .

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