JP5768765B2 - Operation method of electrolytic smelting equipment - Google Patents

Description

  The present invention relates to a method for operating an electrolytic smelting facility. More specifically, the present invention relates to a technique for exchange work performed between energization periods in electrolytic refining and electrowinning.

As a method of electrolytic smelting, electrolytic purification and electrolytic extraction are known.
Electrolytic refining is a post-process of dry smelting and produces high-purity metal from crude metal. The anode used for the electrolytic refining is a crude metal produced by dry smelting, and its purity is increased to such an extent that it can be advantageously subjected to electrolytic refining. On the other hand, the cathode is a product metal, which is a metal having a purity exceeding a certain standard. In electrolytic purification, the target metal elutes from the anode in the form of ions and is deposited on the cathode. Impurities having a higher potential than the target metal contained in the anode are deposited on the bottom of the electrolytic cell as anode slime.
Electrolytic extraction is the last step of the hydrometallurgical process.The target metal is leached from the ore using an appropriate solvent, impurities are removed from the leachate in the liquid purification process, and the target metal ions are concentrated to remove the electrolyte. The target metal is deposited on the cathode from the electrolyte by electrolysis.

  In the electrolytic smelting, a plurality of anodes and cathodes are alternately inserted into an electrolytic bath filled with an electrolytic solution, and electrolysis is performed by energizing between the anode and the cathode. Then, after energization for a predetermined time, the power is interrupted once, the anode and the cathode are replaced, and energization is repeated. Hereinafter, a period from the start of energization to the end of energization is referred to as an energization period, and an operation performed between the energization period and the energization period is referred to as replacement work.

  For example, in the electrolytic refining of copper, the energization time per anode is generally about 15 to 20 days, and a product cathode (electrocopper) that has been energized for 7 to 10 days per anode can be obtained twice. it can. The energizing period for obtaining the first product cathode is referred to as the first half life, and the energizing period for obtaining the second product cathode is referred to as the second half life. This is done by replacing the cathode with a new one and turning it on again.

  On the other hand, the replacement work from the second half life to the first half life is performed according to the following procedure. First, after the end of the second half of the life, make a power outage once. Next, both the anode and the cathode are extracted from the electrolytic cell, the electrolytic solution is discharged, and the anode slime deposited on the bottom of the electrolytic cell is removed. Next, a new anode and cathode are inserted into the electrolytic cell, and the electrolytic solution is supplied. Then, the electrolytic cell is filled with the electrolytic solution, and energization is started after the temperature of the electrolytic solution reaches a predetermined temperature.

By the way, in the electrolytic refining of copper, it is known that the short-circuit rate between the anode and the cathode increases when the temperature of the cathode is reduced to 60 ° C. or less in the initial stage of energization (see Patent Document 1). This is because if the temperature of the cathode is low, acicular electrodeposition occurs near the electrolyte surface.
When a short circuit occurs, power is wasted and operating costs increase. In addition, a cathode that has short-circuited may generate particles or bumps due to excessive electrodeposition or may be partially melted, resulting in an appearance quality that does not meet the standards and being a product.

  Also, in copper electrolytic purification equipment, the electrolytic solution circulates in the electrolytic solution circulation system, and impurities are removed from the electrolytic solution discharged from the electrolytic bath, and the temperature is adjusted to around 60 ° C, which is suitable for copper electrolytic purification. Then, the solution is again supplied to the electrolytic cell. On the other hand, the anode and cathode immediately after replacement are at an outside air temperature (about 0 to 30 ° C.) and the temperature is low. Therefore, the exchanged anode and cathode are warmed by the electrolytic solution and gradually rise in temperature. Then, immediately after the start of liquid supply, the electrolyte is deprived of heat by the anode and the cathode, the temperature is lowered, and the temperature of the electrolyte rises as the temperature of the anode and the cathode rises.

  In the example of the replacement work from the latter half life to the first half life described above, when energization is started immediately after the electrolytic cell is filled with the electrolytic solution, the cathode temperature remains low and the short-circuit rate increases. Therefore, after the electrolytic cell is filled with the electrolytic solution, the short-circuit rate is reduced by starting energization after the temperature of the electrolytic solution reaches a predetermined temperature (for example, 57 ° C.).

  In an industrial electrolytic smelting facility having hundreds to thousands of electrolytic cells, generally, a plurality of electrolytic cells are connected in series and energized. For example, in the case of electrolytic smelting of copper, it is necessary to pass a current of several thousand to several tens of thousands of A through one electrolytic cell. On the other hand, the required voltage is as low as about 0.5 V, This is because it is neither technically easy nor economical to manufacture a low-voltage power supply device. Therefore, a method is adopted in which a plurality of electrolytic cells are electrically connected in series and energized so that the voltage can be controlled to several V to several tens of V. In such an energization method, only a part of the circuit can be short-circuited to cause a power failure in the electrolytic cell therebetween. Since it is uneconomical to install a large number of short-circuit machines so that all the electrolyzers can be blacked out individually, the cost of equipment is high and it is uneconomical. A method of controlling energization and power failure using a short-circuit machine is used. The replacement work as described above is also performed on a group basis.

  For example, replacement work from the second half life to the first half life in the electrolytic refining of copper is performed according to the following procedure. First, after the end of the second half of the life, the group is blacked out once. Next, extraction of the anode and cathode, discharge of the electrolytic solution, removal of anode slime, insertion of a new anode and cathode, and supply of the electrolytic solution are sequentially performed for a plurality of electrolytic cells belonging to the set. All the electrolytic cells are filled with the electrolytic solution, and energization of the set is started after the temperature of the electrolytic solution reaches a predetermined temperature.

  Because the replacement work is performed according to the above procedure, among the multiple electrolytic cells belonging to one set, the electrolytic cell that started the work first completes earlier than the electrolytic cell that started the work last To do. That is, the temperature of the electrolytic solution reaches a predetermined temperature and can be energized. However, current cannot be supplied until the temperature of the electrolytic solution reaches a predetermined temperature in all electrolytic cells. Eventually, in the electrolytic cell that started the work last, energization could not be started until the temperature of the electrolyte reached a predetermined temperature, and the other electrolytic cells were in a state of waiting until the start of energization even after the work was completed. Become. As a result, the entire replacement work takes a long time. Since electrolysis cannot be performed during the replacement work, there is a problem that if the replacement work takes a long time, the operation efficiency decreases accordingly.

Japanese Patent Application Laid-Open No. 08-311678

  In view of the above circumstances, an object of the present invention is to provide a method for operating an electrolytic smelting facility that shortens replacement work and has high operational efficiency.

The method for operating an electrolytic smelting facility according to the first invention is an exchange operation performed between an energization period and an energization period in an assembly composed of a plurality of electrolytic cells having common control of energization and power failure. A discharge step of discharging the electrolytic solution in the electrolytic cell to which the electrolytic cell belongs, and a liquid supply step of supplying the electrolytic solution to the electrolytic cell belonging to the set after the discharging step, wherein in the liquid supply step, the electrolytic cell In addition to supplying the electrolyte solution to the electrolyte solution in addition to the electrolyte solution supplied from the solution supply means provided in the electrolytic cell, the electrolyte solution supplied from another electrolytic cell is supplied. To do.
The operation method of the electrolytic smelting facility according to the second aspect of the present invention is the first aspect, wherein the supply source electrolytic cell supplying the electrolytic solution is an electrolytic cell belonging to the same set as the supply destination electrolytic cell supplied with the electrolytic solution The electrolytic cell is one in which the supply of the electrolytic solution is started earlier than the supply destination electrolytic cell.
The operation method of the electrolytic smelting facility of the third invention is that in the second invention, the supply destination electrolytic cell is an electrolytic cell in which supply of the electrolytic solution is started latest among the electrolytic cells belonging to the set. It is characterized by.
The method for operating an electrolytic smelting facility according to a fourth aspect of the invention is characterized in that, in the second or third aspect of the invention, the supply source electrolytic cell is supplied with an electrolytic solution supplied from a plurality of the supply source electrolytic cells. To do.
The method for operating an electrolytic smelting facility according to a fifth aspect of the present invention is the second, third or fourth aspect of the invention, wherein the feeding of the electrolytic solution from the supply source electrolytic cell to the supply destination electrolytic cell is based on the siphon principle. It is characterized by performing.
The method for operating an electrolytic smelting facility according to a sixth aspect of the present invention is the second, third or fourth aspect of the invention, wherein 4 hours have elapsed since the start of energization of feeding the electrolytic solution from the supply source electrolytic cell to the supply destination electrolytic cell It is characterized by continuing until time.

According to the first invention, since the electrolytic solution supplied from the other electrolytic cell is supplied, the amount of the electrolytic solution supplied to the electrolytic cell is increased, and the time for supplying the electrolytic solution is shortened. The temperature rises faster. Therefore, it is possible to start energization early while reducing the short-circuit rate, and the replacement work can be performed in a short time, so that the operation efficiency is good.
According to the second aspect of the invention, since the electrolytic solution supplied from the electrolytic tank that has started supplying the electrolytic solution early is supplied, the electrolytic solution having a high temperature can be supplied. Therefore, the temperature rise of the electrolytic solution becomes faster.
According to the third aspect of the invention, the amount of electrolyte supplied to the electrolytic cell where the supply of the electrolyte is started latest increases. Therefore, the time for supplying the electrolytic solution in the electrolytic cell is shortened, and the temperature rise of the electrolytic solution is accelerated. As a result, the time for supplying the electrolytic solution is shortened for the entire set.
According to the fourth aspect of the invention, since the electrolytic solution supplied from the plurality of supply source electrolytic cells is supplied, the amount of electrolytic solution supplied to the electrolytic cell is further increased. Therefore, the supply time of the electrolytic solution is further shortened, and the temperature rise of the electrolytic solution is further accelerated.
According to the fifth aspect, since the liquid is fed using the principle of siphon, the liquid feeding is continued until the supply destination electrolytic tank is filled with the electrolytic solution, and when it is filled with the electrolytic solution, the liquid feeding is naturally stopped. And there is no shortage of electrolyte in the source electrolytic cell. In this way, control of the flow rate is unnecessary, and the operation is easy.
According to the sixth aspect of the invention, since the amount of electrolyte supplied is increased until the elapse of 4 hours after the start of energization, the cathode can be sufficiently warmed at the initial stage of energization, and the short-circuit rate can be reduced.

It is an arrangement plan of an electrolytic cell of a general copper electrolytic purification facility. 1 is a schematic view of a general copper electrolytic purification facility. FIG. It is explanatory drawing of liquid feeding of the electrolyte solution from a supply source electrolytic cell to a supply destination electrolytic cell. It is a temperature change graph of an electrode and electrolyte solution, (a) is an Example, (b) is a comparative example.

Next, an embodiment of the present invention will be described with reference to the drawings.
In electrolytic smelting, a plurality of anodes and cathodes are alternately inserted into an electrolytic bath filled with an electrolytic solution, and electrolysis is performed by energizing between the anode and the cathode. Then, after energization for a predetermined time, the power is interrupted once, the anode and the cathode are replaced, and energization is repeated. Hereinafter, the period from the start of energization to the end of energization is referred to as the energization period, and the work performed between the energization period and the energization period is referred to as replacement work.

  Moreover, in the electrolytic smelting equipment having several hundred to one thousand electrolytic cells, ten to ten or more electrolytic cells are made into one set, and the electrolytic cells belonging to the set are electrically connected in series. Therefore, energization and power outage are not controlled for each electrolytic cell, and energization and power outage are controlled in units of groups. The replacement work as described above is also performed on a group basis.

  The present invention is a method relating to an exchange operation involving replacement of an electrolytic solution in an electrolytic smelting facility having a set of a plurality of electrolytic cells having common control of energization and power failure as described above.

  In addition, the operation method of the electrolytic smelting equipment of the present invention can be applied to an electrolytic purification equipment that performs electrolytic purification and an operating method of an electrolytic collection equipment that performs electrolytic collection. Moreover, the target metal used as a product is not particularly limited. For example, copper, lead, nickel, gold, silver, and the like are known as target metals for electrolytic purification, and nickel, cobalt, copper, silver, gold, zinc, and the like are known as target metals for electrolytic collection. In any case, since the operation method is the same, the following description will be made taking copper electrolytic purification as an example.

First, the structure of a general copper electrolytic purification facility will be described.
In FIG. 2, 1 is an electrolysis tank, 2 is a drainage tank, 3 is a pump, 4 is a heat exchanger, 5 is a liquid supply tank, and these form an electrolyte circulation system.

  A plurality of crude copper anodes and pure copper cathodes are alternately inserted into the electrolytic cell 1 to fill the electrolytic solution. The electrolytic solution is discharged from the electrolytic solution discharge portion of the electrolytic cell 1 and is supplied to the drainage cell 2 by a drop. The drainage tank 2, the heat exchanger 4 and the liquid supply tank 5 are connected by a pipe, and a pump 3 is interposed in the pipe. By driving the pump 3, a predetermined flow rate of the electrolyte is supplied from the drainage tank 2 to the heat exchanger 4 or the supply tank 5. The electrolytic solution supplied to the heat exchanger 4 is heated or cooled and supplied to the liquid supply tank 5. Then, the electrolytic solution discharged from the liquid supply tank 5 is supplied to the electrolytic tank 1 by a drop.

A flow control valve is interposed in the liquid supply pipe 6 connecting the liquid supply tank 5 and the electrolytic tank 1, and the supply, stop, and supply amount of the electrolytic solution to the electrolytic tank 1 are controlled by this flow control valve. It can be adjusted. Further, a weir-type flow rate control means is provided in the electrolytic solution discharge part of the electrolytic cell 1 so that the liquid level of the electrolytic solution can be adjusted.
The liquid supply pipe 6 corresponds to the liquid supply means described in the claims. The liquid supply means means means for supplying the electrolytic solution previously provided in the electrolytic cell as described above.

  Thus, the electrolytic solution circulates in the electrolytic solution circulation system, and the electrolytic solution discharged from the electrolytic cell 1 is adjusted to a temperature suitable for copper electrolytic purification (55 to 65 ° C.), The liquid is again supplied to the electrolytic cell 1. Further, impurities are removed while the electrolytic solution circulates in the electrolytic solution circulation system. The removal of impurities in the electrolytic solution can be performed by, for example, sending a part of the electrolytic solution from the electrolytic solution circulation system to the liquid purification step, and using a method such as concentration cooling or electrolytic collection to remove impurities contained in the electrolytic solution or excessive amounts. This is done by removing the copper.

  As shown in FIG. 1, in an electrolytic purification facility, several hundred to thousand electrolytic cells 1 are arranged in a building. These electrolyzers 1 are divided into a plurality of groups, with ten to ten or more adjacent tanks as one set. And ten to dozen or more electrolytic cells 1 belonging to one set are electrically connected in series to control energization and power failure in units of sets. In the example shown in FIG. 1, the adjacent 18 electrolytic cells 1a to 1r are set as a set A, and the electrolytic cells 1a to 1r are electrically connected in series.

  In electrolytic refining of copper, in general, the energization time per anode is about 15 to 20 days, and a product cathode (electrocopper) subjected to energization for 7 to 10 days per anode can be obtained twice. Hereinafter, the energization period for obtaining the first product cathode is referred to as the first half life, and the energization period for obtaining the second product cathode is referred to as the second half life.

  The replacement work from the first half life of the group A to the second half life is performed after the first half life is completed, the group A is once blacked out, the cathodes inserted in the electrolyzers 1a to 1r are replaced with new ones, and the group A again. This is done by starting the energization of.

On the other hand, the replacement work from the latter half life of the group A to the first half life is performed in the following procedure.
(1) First, after the end of the second half life, the group A is blacked out.
(2) Next, the anode and cathode are extracted from the electrolytic cell. Here, the anode and the cathode are extracted using an overhead crane provided in the building. Therefore, the operation is sequentially performed for each of the electrolytic cells 1a to 1r belonging to the set A. For example, the anode and cathode of the electrolytic cell 1a are first extracted, then the anode and cathode of the electrolytic cell 1b are extracted, the same operation is performed in the order of the electrolytic cell 1c,..., 1g, and finally the electrolytic cell 1r. Extract the anode and cathode.

(3) The electrolytic solution in the electrolytic cell is sequentially discharged from the electrolytic cell from which the anode and cathode are extracted (discharge process). Therefore, the electrolytic solution is discharged in the order of the electrolytic cells 1a,.
(4) The anode slime and the like deposited on the bottom of the electrolytic cell are sequentially removed from the electrolytic cell after discharging the electrolytic solution, and new anodes and cathodes are inserted. Again, the anode and cathode are inserted using an overhead crane. Therefore, removal of anode slime and the like and insertion of the anode and cathode are performed in the order of the electrolytic cells 1a,.

(5) The electrolytic solution is sequentially supplied from the electrolytic cell in which the anode and the cathode have been inserted (liquid supply step). Therefore, the electrolytic solution supply is started in the order of the electrolytic cells 1a,.
(6) After all the electrolytic cells 1a to 1r are filled with the electrolytic solution and the temperature of the electrolytic solution in all the electrolytic cells 1a to 1r reaches a predetermined temperature (for example, 57 ° C.), the energization of the set A is started. To do.

  In copper electrolytic refining, it is known that the short-circuit rate between the anode and the cathode increases when the temperature of the cathode is lowered to 60 ° C. or less at the beginning of energization. This is because if the temperature of the cathode is low, acicular electrodeposition occurs near the electrolyte surface. Here, the short-circuit rate is n / (D × N) (n: the total number of cathodes in which a short circuit occurred during a predetermined period, D: the number of energization days during a predetermined period, N: the number of cathodes manufactured during a predetermined period. ).

  Further, the anode and cathode immediately after replacement are at the outside air temperature (about 0 to 30 ° C.) and the temperature is low. Therefore, the replaced anode and cathode are warmed by the electrolytic solution whose temperature is adjusted to 55 to 65 ° C., and the temperature gradually rises. Then, immediately after the start of liquid supply, the electrolyte is deprived of heat by the anode and the cathode, the temperature is lowered, and the temperature of the electrolyte rises as the temperature of the anode and the cathode rises. Therefore, after the electrolytic cells 1a to 1r are filled with the electrolytic solution, the short-circuit rate is reduced by starting energization after the temperature of the electrolytic solution reaches a predetermined temperature.

  Among the electrolytic cells 1a to 1r belonging to the set A, the electrolytic cell 1a that started the extraction operation of the anode and the cathode was filled with the electrolytic solution earlier than the electrolytic cell 1r that started the operation. The temperature reaches the predetermined temperature quickly. That is, it will be in the state which may energize. However, in all the electrolytic cells 1a-1r, it cannot energize until the temperature of electrolyte solution reaches predetermined temperature.

  In the above (5) liquid supply step, the present invention adds the electrolytic solution supplied to the electrolytic cell 1 to the electrolytic solution supplied from the liquid supply pipe 6 provided in the electrolytic cell 1, and other electrolytic cells. 1 is characterized in that the replacement work is shortened by supplying the electrolyte supplied from 1 (hereinafter also referred to as auxiliary supply).

  For example, as indicated by the solid line arrow in FIG. 1, among the electrolytic cells 1 a to 1 r belonging to the set A, the electrolytic cell 1 a in which the supply of the electrolytic solution is started earliest is the supply source electrolytic cell 1 a, and the latest electrolytic solution The electrolytic cell 1r from which the liquid supply is started is used as the supply destination electrolytic cell 1r, and the electrolytic solution supplied from the supply source electrolytic cell 1a is supplied to the supply destination electrolytic cell 1r. Hereinafter, for convenience of explanation, an electrolytic cell that supplies an electrolytic solution is referred to as a source electrolytic cell, and an electrolytic cell that is supplied with an electrolytic solution supplied by a source electrolytic cell is referred to as a destination electrolytic cell.

  Since the electrolytic solution supplied from the supply source electrolytic cell 1 a is supplied to the supply destination electrolytic cell 1 r, the supply amount is increased as compared with the normal supply amount supplied from the liquid supply pipe 6. Therefore, the time for supplying the electrolytic solution in the supply destination electrolytic tank 1r is shortened, and the temperature rise of the electrolytic solution is accelerated. Here, since the supply destination electrolytic tank 1r is the latest electrolytic tank in which the supply of the electrolytic solution is started, the supply time of the electrolytic solution is shortened as a whole, and the temperature rise of the electrolytic solution is accelerated. If it does so, electricity supply can be started early, reducing a short circuit rate, and exchange work can be made into a short time. And since the exchange work which cannot electrolyze can be made into a short time, operation efficiency becomes good by the part. In addition, as a result of the reduction in the short-circuit rate, power loss and correction work are reduced, and the product yield is improved.

  In addition, since the electrolytic solution is supplied to the supply source electrolytic tank 1a from the liquid supply pipe 6, even if the electrolytic solution is supplied to the supply destination electrolytic tank 1r, the electrolytic solution is not short.

Various means such as a pump can be used to feed the electrolytic solution from the supply source electrolytic tank 1a to the supply destination electrolytic tank 1r, but it is preferable to use the siphon principle.
Specifically, as shown in FIG. 3, one end of a tube 7 such as a hose is immersed in the electrolytic solution in the supply source electrolytic tank 1a, and the other end is on the supply destination electrolytic tank 1r side. The position is lower than the liquid level of the electrolyte in the tank 1a. At this time, if the pipe 7 is filled with the electrolytic solution, the electrolytic solution in the supply source electrolytic cell 1a is fed to the supply destination electrolytic cell 1r without any other operation. For example, if the entire tube 7 is immersed in the electrolytic solution in the supply source electrolytic tank 1a and the end thereof is moved to the supply destination electrolytic cell 1r side with the end covered, the electrolytic solution is put into the tube 7 Since it can be filled, the electrolyte can be fed when the lid is removed.

  In this way, when the liquid is fed using the siphon principle, there is a difference between the liquid level height of the electrolytic solution in the supply source electrolytic tank 1a and the liquid level height of the electrolytic solution in the supply destination electrolytic tank 1r. The liquid supply continues, and when it reaches the same height, the liquid supply stops. That is, the liquid feeding is continued until the supply destination electrolytic cell 1r is filled with the electrolytic solution, and the liquid feeding naturally stops when the electrolytic tank is filled with the electrolytic solution. And there is no shortage of electrolyte in the supply source electrolytic cell 1a. In this way, control of the flow rate is unnecessary, and the operation is easy.

The supply source electrolytic cell is not limited to the electrolytic cell 1a in which the supply of the electrolytic solution is started earliest, but may be another electrolytic cell belonging to the set A. Further, the supply source electrolytic cell is not limited to the electrolytic cell 1r where the supply of the electrolytic solution is started latest, and may be another electrolytic cell belonging to the set A. The supply source electrolytic cell and the supply destination electrolytic cell may each be one electrolytic cell or a plurality of electrolytic cells. Furthermore, the supply source electrolytic cell may be any electrolytic cell in which the supply of the electrolytic solution is started earlier than the supply destination electrolytic cell, and the combination thereof is not particularly limited.
What is necessary is just to select the combination of a supply source electrolytic cell and a supply destination electrolytic cell so that the time of exchange work may become short as the group A whole.

  For example, the electrolytic solution supplied from a plurality of supply source electrolytic cells 1a and 1b may be supplied to one supply destination electrolytic cell 1r, or the electrolytic solution supplied from one supply source electrolytic cell 1a. The liquid may be supplied to a plurality of supply destination electrolytic cells 1g and 1r. In addition, the electrolytic solution supplied from the electrolytic cell 1a may be supplied to the electrolytic cell 1r and simultaneously, the electrolytic solution supplied from the electrolytic cell 1b may be supplied to the electrolytic cell 1g.

If the electrolytic cell in which the supply of the electrolytic solution is started earlier than the supply destination electrolytic cell is set as the supply source electrolytic cell, the temperature of the electrolytic solution in the supply source electrolytic cell is increased by the time difference. For this reason, since the electrolyte solution having a high temperature can be supplied to the supply destination electrolytic tank, the temperature rise of the electrolyte solution in the supply destination electrolytic tank becomes faster.
Moreover, if the electrolyte supplied from the plurality of supply source electrolytic cells is supplied to the supply destination electrolytic cell, the amount of supply of the electrolyte further increases. Therefore, the supply time of the electrolytic solution in the supply destination electrolytic tank is further shortened, and the temperature rise of the electrolytic solution is further accelerated.

  As described above, it is known that, in the electrolytic refining of copper, when the cathode temperature is lowered to 60 ° C. or less at the initial stage of energization, the short-circuit rate between the anode and the cathode is increased. On the other hand, even when the energization of the set A was started after the temperature of the electrolyte in all the electrolytic cells 1a to 1r reached a predetermined temperature (for example, 57 ° C.), the supply of the electrolyte was started latest. The electrolytic solution in the electrolytic cell 1r does not reach 60 ° C. immediately after the start of energization.

Therefore, it is preferable to continue feeding the electrolytic solution from the supply source electrolytic cell to the supply destination electrolytic cell until the cathode temperature reaches 60 ° C. even after the start of energization. In this way, the cathode can be sufficiently warmed at the beginning of energization, and the short-circuit rate can be reduced.
The inventors of the present application have found that the temperature of the cathode reaches 60 ° C. after 4 hours from the start of energization. Therefore, it is preferable to continue feeding the electrolytic solution from the supply source electrolytic tank to the supply destination electrolytic tank until 4 hours have elapsed after the start of energization.

(Other embodiments)
In the above embodiment, the supply source electrolytic cell and the supply destination electrolytic cell belong to the same group A, but the supply source electrolytic cell may be an electrolytic cell belonging to a group different from the group to which the supply destination electrolytic cell belongs. For example, as indicated by a broken line arrow in FIG. 1, an electrolytic cell 1r belonging to the set A is a supply destination electrolytic cell 1r, an electrolytic cell 1x belonging to the set B adjacent to the set A is a supply source electrolytic cell 1x, The electrolytic solution supplied from the tank 1x may be supplied to the supply destination electrolytic tank 1r.

  If the supply source electrolytic cell 1x is energized, the temperature of the electrolytic solution is also increased by Joule heat. Therefore, since the electrolyte solution having a high temperature can be supplied to the supply destination electrolytic cell 1r, the temperature rise of the electrolyte solution in the supply destination electrolytic cell 1r becomes faster.

  When the supply source electrolytic cell is an electrolytic cell belonging to a group different from the set to which the supply destination electrolytic cell belongs, the supply source electrolytic cell is preferably an electrolytic cell after 4 hours have elapsed from the start of energization. It is more preferable that the electrolytic cell is one day later. This is because the temperature of the electrolyte is sufficiently high after 4 hours have elapsed from the start of energization. Moreover, it is because the temperature of electrolyte solution is stable if one day has passed since the start of energization.

In addition, it is preferable to collect the electrolyte solution on the discharge side from the supply source electrolytic cell rather than the liquid supply side. This is because the discharge-side electrolyte has a higher temperature and a higher copper concentration than the supply-side electrolyte.
Furthermore, it is preferable to collect the electrolyte solution near the anode from the supply source electrolytic cell rather than near the cathode. This is because the electrolyte solution in the vicinity of the anode has a locally higher temperature and a higher copper concentration than the average of the electrolyte solution in the entire electrolytic cell.

In both the examples and comparative examples, electrolytic purification of copper was performed under the following conditions.
Electrolytic cell used was a structure lined vinyl chloride on the surface of the concrete, the length 3000 mm, width 1260 mm, the depth 1500～1700Mm (both internal dimensions), the capacity of the electrolytic solution is 3.4 m ² . 27 electrolytic copper anodes of 99.2% copper grade and 26 pure copper cathodes of 99.99% copper grade were alternately arranged per electrolytic cell, and were inserted so that the distance between the anode and the cathode was 105 mm. The electrode area of the anode is 1015 mm wide, 1015 mm long, and has an initial thickness of about 36 mm. The electrode area of the cathode is 1070 mm wide, 1050 mm long, and an initial thickness of about 0.7 mm.

8 days (approx. 200 hours) after power is cut off, only the cathode is lifted, washed and discharged as copper (first half life), then a new cathode is inserted and again after 8 days, the anode and cathode are lifted and discharged (Second half life) The operation of 16 days of 1 life was repeated 13 times (about 30 weeks).
The flow rate of the electrolyte supplied from the supply pipe is 15 L / min, and the liquid temperature is 60 ° C. The composition of this electrolytic solution is a copper concentration of 46 to 50 g / L and a free sulfuric acid concentration of 170 to 200 g / L. The cathode current density during energization is 300 A / m ² .
During energization, the occurrence of a short circuit was detected by changing the electrolytic cell voltage, monitoring the heat generated by an infrared camera, measuring with a magnetic meter, etc., and correcting each time it was discovered.

  To measure the temperature of an electrode in an operation in the first half of the life, a thermistor thermometer is attached to the center of the electrode with an adhesive to measure the temperature of the electrode, and the silicon resin directly contacts the electrolyte. Covered not to. In order to measure the temperature of the electrolytic solution, the same type of thermistor thermometer was also installed in the electrolytic solution discharge part of the electrolytic cell. These two thermistor thermometers were connected to a data logger so that the temperature of the electrode and electrolyte could be measured continuously.

(Example)
In the replacement work from the second half life to the first half life, the electrolytic solution supplied to the electrolytic tank is added to the electrolytic solution supplied from the liquid supply pipe, and the electrolytic solution supplied from the adjacent electrolytic tank is supplied. (Auxiliary liquid supply). Here, the auxiliary liquid supply was performed according to the principle of a siphon using a hose.

As a result, the temperature of the electrode and the electrolyte at the beginning of energization in a certain first half life changed as shown in FIG. That is, the temperature of the electrode and the electrolyte rapidly increased immediately after the start of the auxiliary liquid supply, and energization could be started early. Moreover, the temperature of the electrode and the electrolyte solution became a quasi-steady state in about two and a half hours from the start of energization. Therefore, the auxiliary liquid supply was completed in about 3 hours from the start.
In addition, during the 13-life period, the occurrence of shorts in the first half life was 11 sheets, and the short-circuit rate was 0.4% (= 11 sheets / (8 days × 26 sheets × 13 lives)).

(Comparative example)
In the replacement work from the second half life to the first half life, the electrolytic solution was supplied to the electrolytic cell only by the liquid supply pipe.

As a result, the temperature of the electrode and the electrolyte at the beginning of energization in a certain first half life changed as shown in FIG. That is, the temperature of the electrode and the electrolyte increased after the start of energization, but the increase was more gradual than in the examples. In addition, it took time for the temperature of the electrolytic solution to reach 60 ° C. compared to the example. It took about 4 hours from the start of energization to reach a quasi-steady state.
In addition, during the 13-life period, the number of short-circuits in the first half life was 24 sheets, and the short-circuit rate was 0.9% (= 11 sheets / (8 days × 26 sheets × 13 lives)).

  As a result, it was confirmed that the short-circuit rate can be reduced by applying the present invention. This is considered to be because the temperature of the electrolytic solution reaches 60 ° C. earlier than in the comparative example.

1, 1a-1r, 1x Electrolysis tank 2 Drainage tank 3 Pump 4 Heat exchanger 5 Liquid supply tank 6 Liquid supply pipe 7 Pipe

Claims (6)

It is a replacement work performed between the energization period and the energization period in an assembly consisting of a plurality of electrolytic cells with common control of energization and power failure,
A discharging step of discharging the electrolytic solution in the electrolytic cell belonging to the set;
A liquid supply step of supplying an electrolytic solution to the electrolytic cell belonging to the set after the discharging step,
In the liquid supplying step, the electrolytic solution supplied to the electrolytic cell is added to the electrolytic solution supplied from the liquid supplying means provided in the electrolytic cell, and the electrolytic solution supplied from another electrolytic cell is supplied. A method for operating an electrolytic smelting facility, characterized by being performed by liquefying. The supply source electrolytic cell that supplies the electrolytic solution started to supply the electrolytic solution earlier than the supply destination electrolytic cell among the electrolytic cells belonging to the same set as the supply destination electrolytic cell to which the electrolytic solution was supplied 2. The method for operating an electrolytic smelting facility according to claim 1, wherein the method is an electrolytic cell. 3. The method of operating an electrolytic smelting facility according to claim 2, wherein the supply source electrolytic cell is an electrolytic cell in which supply of the electrolytic solution is started latest among the electrolytic cells belonging to the set. 4. The method for operating an electrolytic smelting facility according to claim 2, wherein the supply electrolytic cell is supplied with an electrolytic solution supplied from a plurality of the supply electrolytic cells. 5. The method of operating an electrolytic smelting facility according to claim 2, 3 or 4, wherein the feeding of the electrolytic solution from the supply source electrolytic cell to the supply destination electrolytic cell is performed using a siphon principle. The operation of the electrolytic smelting equipment according to claim 2, 3 or 4, wherein the feeding of the electrolytic solution from the supply source electrolytic tank to the supply destination electrolytic tank is continued until 4 hours have elapsed after the start of energization. Method.

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