Production equipment and method for nickel chloride aqueous solution

Abstract

To provide an apparatus and a method for producing an aqueous solution of nickel chloride which can obtain an aqueous solution of nickel chloride from which dissolved chlorine gas has been removed.SOLUTION: There is provided an apparatus AA for producing an aqueous solution of nickel chloride which comprises a dissolution tank 1 in which a first nickel raw material is chlorine leached to obtain an aqueous solution of nickel chloride and an adjustment tank 3 in which the aqueous solution of nickel chloride discharged from the dissolution tank 1 is brought into contact with a second nickel raw material to leach the second nickel raw material with chlorine gas dissolved in the aqueous solution of nickel chloride. Since the chlorine gas dissolved in the aqueous solution of nickel chloride is consumed to leach the second nickel raw material, the chlorine gas can be removed from the aqueous solution of nickel chloride.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a manufacturing facility and a manufacturing method for an aqueous nickel chloride solution. More specifically, the present invention relates to a facility and a method for producing an aqueous nickel chloride solution by chlorine leaching of a nickel raw material.

Background Art

[0002] Nickel chloride is used for nickel plating. Also, nickel chloride is used as a raw material for electrode materials of multilayer ceramic capacitors and nickel powder for conductive pastes. As the above nickel chloride, an aqueous nickel chloride solution or nickel chloride crystals obtained by crystallizing the aqueous nickel chloride solution are used.

[0003] Patent Documents 1 and 2 disclose methods for obtaining an aqueous nickel chloride solution by dissolving a nickel raw material in hydrochloric acid. Also, Patent Document 3 discloses a method for obtaining an aqueous nickel chloride solution by chlorine leaching of a nickel raw material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Chlorine gas is dissolved in the aqueous nickel chloride solution obtained by chlorine leaching. The dissolved chlorine gas may be released due to an increase in the temperature of the aqueous nickel chloride solution or the like. Since chlorine gas has a pungent odor and is highly toxic, it is required to remove the chlorine gas dissolved in the aqueous nickel chloride solution in advance.

[0006] In view of the above circumstances, the present invention aims to provide a production facility and method for producing an aqueous nickel chloride solution from which dissolved chlorine gas has been removed. [Means for solving the problem]

[0007] The production apparatus for a nickel chloride aqueous solution according to the first invention is characterized by comprising: a dissolution tank that obtains a nickel chloride aqueous solution by chlorine leaching a first nickel raw material; and a conditioning tank that brings the nickel chloride aqueous solution discharged from the dissolution tank into contact with a second nickel raw material and leaches the second nickel raw material with chlorine gas dissolved in the nickel chloride aqueous solution. The production apparatus for nickel chloride aqueous solution of the second invention is characterized in that, in the first invention, the adjustment tank comprises a tank body, a liquid passage plate provided to divide the tank body vertically and on which the second nickel raw material is placed, a supply port for supplying the nickel chloride aqueous solution to the lower part of the tank body below the liquid passage plate, and a discharge port for discharging the nickel chloride aqueous solution from the upper part of the tank body above the liquid passage plate. The third invention provides a method for producing an aqueous nickel chloride solution, comprising: a leaching step of obtaining an aqueous nickel chloride solution by leaching a first nickel raw material with chlorine; and a dechlorination gas step of bringing the aqueous nickel chloride solution into contact with a second nickel raw material and leaching the second nickel raw material with chlorine gas dissolved in the aqueous nickel chloride solution. The method for producing an aqueous nickel chloride solution of the fourth invention is characterized in that, in the third invention, the second nickel raw material is electrolytic nickel. [Effects of the Invention]

[0008] According to the first invention, chlorine gas dissolved in the nickel chloride aqueous solution is consumed in the leaching of the second nickel raw material, thereby removing chlorine gas from the nickel chloride aqueous solution. According to the second invention, the nickel chloride aqueous solution comes into contact with the second nickel raw material as it flows from bottom to top inside the adjustment tank, resulting in good contact efficiency between the nickel chloride aqueous solution and the second nickel raw material, and thus chlorine gas is easily removed. According to the third invention, the chlorine gas dissolved in the nickel chloride aqueous solution is consumed in the leaching of the second nickel raw material, thereby removing the chlorine gas from the nickel chloride aqueous solution. According to the fourth invention, since the second nickel raw material is electrolytic nickel, the contamination of nickel chloride aqueous solution with components other than nickel can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall configuration diagram of a manufacturing facility according to one embodiment. [Figure 2] This is a longitudinal cross-section of the dissolution tank. [Figure 3] This is a longitudinal cross-section of the initial fluid tank. [Figure 4] This is a longitudinal cross-section of the adjustment tank. [Figure 5] This is an explanatory diagram showing the state of the dissolution tank during (1) the raw material charging process and (2) the liquid supply process. [Figure 6] (3) This is an explanatory diagram showing the state of the dissolution tank in the depressurization process and (4) the chlorine gas supply process. [Modes for carrying out the invention]

[0010] Next, embodiments of the present invention will be described based on the drawings. (manufacturing equipment) The nickel chloride aqueous solution manufacturing equipment according to one embodiment of the present invention is equipment for manufacturing a nickel chloride aqueous solution by chlorine leaching of a nickel raw material. The nickel raw material is not particularly limited as long as it contains nickel. However, if electrolytic nickel is used as the nickel raw material, a high-purity nickel chloride aqueous solution can be obtained without any special purification treatment.

[0011] Electrolytic nickel can be produced, for example, by wet nickel smelting. In wet nickel smelting, raw materials such as nickel matte and nickel-cobalt mixed sulfide are chlorinated. A purification treatment is performed to remove impurities from the leachate to obtain an aqueous nickel chloride solution. Electrolytic nickel can then be obtained by electrolysis using the aqueous nickel chloride solution as the electrolyte.

[0012] In order to increase the dissolution efficiency, it is preferable that the electrolytic nickel be smaller. For example, it is preferable to use electrolytic nickel in the form of a plate cut to a size of 100 mm × 100 mm or less. Also, button-shaped electrolytic nickel may be used. The smaller the size of the electrolytic nickel, the larger the contact area with the nickel chloride aqueous solution, and thus the chlorine leaching proceeds more efficiently.

[0013] As shown in FIG. 1, the manufacturing equipment AA of the present embodiment includes a dissolution tank 1, a starting solution tank 2, an adjustment tank 3, and a final solution tank 4. The manufacturing equipment AA also has a control device 5 that acquires measurement values from various measuring instruments and controls the operations of various valves, pumps, etc. A computer such as a PLC can be used as the control device 5.

[0014] The dissolution tank 1 is a tank that performs chlorine leaching on a nickel raw material to obtain a nickel chloride aqueous solution. Hereinafter, the nickel raw material processed in the dissolution tank 1 is referred to as the first nickel raw material. The dissolution tank 1 only needs to be able to perform chlorine leaching on the first nickel raw material, and its configuration is not particularly limited, but it can be the configuration described below.

[0015] [[ID=!4]] As shown in FIG. 2, the dissolution tank 1 has a tank body 10. The tank body 10 is preferably a tank having airtightness. The shape of the tank body 10 is not particularly limited and may be cylindrical or rectangular.

[0016] An inlet 12 is provided at the center of the top plate of the tank body 10. The first nickel raw material N1 is loaded into the tank body 10 from the inlet 12. The inlet 12 is closed by a lid 13. Also, a water seal portion for water-sealing between the inlet 12 and the lid 13 is provided. Therefore, by closing the inlet 12 with the lid 13 and water-sealing it, the tank body 10 can be made airtight.

[0017] Inside the trough body 10, a sieve plate 15 is provided. The sieve plate 15 is horizontally provided so as to cross near the upper and lower centers of the trough body 10. The internal space of the trough body 10 is partitioned into two upper and lower spaces by the sieve plate 15. As the sieve plate 15, a plate material having a plurality of holes or slits, such as a punching plate or a wedge wire screen, is used. The first nickel raw material N1 charged from the charging port 12 is placed on the sieve plate 15. On the other hand, the liquid passes through the sieve plate 15 and flows down from the upper space to the lower space of the trough body 10.

[0018] A liquid supply port 16 is provided on the top plate of the trough body 10. The liquid supply port 16 is connected to a liquid supply device. The dissolution starting liquid supplied from the liquid supply device flows into the trough body 10 from the liquid supply port 16. Details of the liquid supply device will be described later.

[0019] An overflow port 17 is provided at the upper part and a drain port 18 is provided at the lower part on the side wall of the trough body 10. The overflow port 17 is above the sieve plate 15 and is provided at a position close to the top plate of the trough body 10. On the other hand, the drain port 18 is below the sieve plate 15 and is provided at a position close to the sieve plate 15. Both the overflow port 17 and the drain port 18 are used for discharging the liquid in the trough body 10.

[0020] An outlet 19 is further provided on the side wall of the trough body 10. The outlet 19 is below the drain port 18 and is provided at a position close to the bottom of the trough body 10. A return port 20 is provided on the top plate of the trough body 10.

[0021] The outlet 19 and the return port 20 are connected by a small circulation pipe 51. A small circulation pump 71 is provided in the small circulation pipe 51. The suction side of the small circulation pump 71 is connected to the outlet 19, and the discharge side is connected to the return port 20. Therefore, when the small circulation pump 71 is driven, the liquid can be extracted from the lower part of the trough body 10 and returned to the upper part of the trough body 10.

[0022] A heat exchanger 73 is provided in the small circulation pipe 51. The heat exchanger 73 cools the liquid flowing through the small circulation pipe 51. Therefore, the liquid withdrawn from the tank body 10 is cooled and then returned to the tank body 10.

[0023] Inside the tank body 10, an injection unit 21 is provided near the underside of the top plate. The return port 20 is connected to the injection unit 21. The liquid that has circulated through the small circulation pipe 51 is injected from the injection unit 21, wetting the first nickel raw material N1.

[0024] The injection unit 21 consists of a small annular tube 21a and a large annular tube 21b arranged concentrically. Each of the small annular tube 21a and the large annular tube 21b has multiple holes provided at predetermined intervals, and liquid is injected from these holes. The charging port 12 is located inside the small annular tube 21a. Therefore, the injection unit 21 does not get in the way when the first nickel raw material N1 is charged.

[0025] In this embodiment, the initial dissolution liquid flows directly down from the liquid inlet 16. Alternatively, the liquid inlet 16 may be connected to an injection unit. This injection unit may be the same as the injection unit 21 connected to the return port 20, or it may be a separate component. By connecting the liquid inlet 16 to the injection unit, the initial dissolution liquid can be injected into the first nickel raw material N1.

[0026] A chlorine gas supply pipe 52 is connected to the tank body 10. The open end of the chlorine gas supply pipe 52 is inside the tank body 10 and located below the slat plate 15. The other end of the chlorine gas supply pipe 52 is connected to a chlorine gas supply source 74. A gas cylinder containing liquefied chlorine can be used as the chlorine gas supply source 74. A flow control valve 61 is provided on the chlorine gas supply pipe 52. Chlorine gas can be supplied to the inside of the tank body 10 by the chlorine gas supply pipe 52. The amount of chlorine gas supplied can also be adjusted by adjusting the opening of the flow control valve 61. The chlorine gas supply pipe 52, the flow control valve 61, and the chlorine gas supply source 74 constitute a chlorine gas supply device that supplies chlorine gas to the dissolution tank 1.

[0027] A pressure gauge 22 is provided on the top plate of the tank body 10. The pressure gauge 22 can measure the pressure in the gas phase inside the dissolution tank 1.

[0028] A ring collection port 23 is provided on the top plate of the tank body 10. A ring collection tube 53 is connected to the ring collection port 23. An exhaust valve 62 is also provided on the ring collection tube 53. Opening the exhaust valve 62 allows the gas inside the tank body 10 to be exhausted. Closing the exhaust valve 62 makes the tank body 10 airtight.

[0029] The gas phase within the dissolution tank 1 is filled with chlorine gas supplied from the chlorine gas supply pipe 52. The first nickel raw material N1 is also moistened by the liquid sprayed from the spray unit 21. This results in the first nickel raw material N1 being covered with a liquid film under a chlorine gas atmosphere. The chlorine gas is absorbed by the liquid covering the first nickel raw material N1, and the chlorine leaching reaction of the first nickel raw material N1 proceeds, generating an aqueous nickel chloride solution. In this way, the first nickel raw material N1 is chlorinated within the dissolution tank 1 to produce an aqueous nickel chloride solution. The generated aqueous nickel chloride solution is temporarily stored at the bottom of the dissolution tank 1 and discharged from the drain port 18 or the outlet 19.

[0030] As shown in Figure 3, the initial liquid tank 2 is a tank for storing the initial dissolution liquid. The initial dissolution liquid is either an aqueous nickel chloride solution or water. Pure water is preferred as the initial dissolution liquid. This allows for the acquisition of a high-purity aqueous nickel chloride solution. The shape of the initial liquid tank 2 is not particularly limited and may be cylindrical or rectangular. Furthermore, the initial liquid tank 2 does not require the same airtightness as the dissolution tank 1. However, since chlorine gas is dissolved in the initial dissolution liquid during steady operation, it is preferable that the gas phase portion of the initial liquid tank 2 is also enclosed.

[0031] A liquid outlet 31 and a liquid inlet 32 ​​are provided at the bottom of the initial liquid tank 2. A water addition port 33 and a hydrochloric acid addition port 34 are provided on the top plate of the initial liquid tank 2. The initial liquid tank 2 has a stirrer 35. The initial liquid solution can be stirred by driving the stirrer 35. The initial liquid tank 2 is equipped with a pH meter 36. The pH of the initial liquid solution can be measured using the pH meter 36. The initial liquid tank 2 is equipped with a liquid level gauge 37. The liquid level in the initial liquid tank 2 can be measured using the liquid level gauge 37.

[0032] As shown in Figure 1, one end of a supply pipe 54 is connected to the liquid outlet 31 of the initial liquid tank 2. The other end of the supply pipe 54 is connected to the liquid inlet 16 of the dissolution tank 1. A supply pump 72 is provided on the supply pipe 54. When the supply pump 72 is driven, the initial dissolution liquid in the initial liquid tank 2 is supplied to the dissolution tank 1. Therefore, the initial liquid tank 2, the supply pipe 54, and the supply pump 72 constitute a liquid supply device that supplies the initial dissolution liquid to the dissolution tank 1.

[0033] One end of a drain pipe 55 is connected to the liquid inlet 32 ​​of the initial liquid tank 2. The other end of the drain pipe 55 is connected to the drain port 18 of the dissolution tank 1. A drain valve 63 is provided in the drain pipe 55. Therefore, when the drain valve 63 is opened, the nickel chloride aqueous solution produced in the dissolution tank 1 is discharged to the initial liquid tank 2 via the drain pipe 55. The supply pipe 54 and the drain pipe 55 constitute a large circulation channel that circulates the liquid between the initial liquid tank 2 and the dissolution tank 1.

[0034] One end of an overflow pipe 56 is connected to the overflow port 17 of the dissolution tank 1. The other end of the overflow pipe 56 is connected to the downstream side (starting tank 2 side) of the drain valve 63 of the drain pipe 55. The liquid that overflows from the overflow port 17 of the dissolution tank 1 is discharged to the starting tank 2 via the overflow pipe 56 and the drain pipe 55.

[0035] As shown in Figure 3, a water addition device is provided in the initial liquid tank 2. The water addition device includes a water supply source 75, a water supply pipe 57, and a flow control valve 64. A water storage tank, utility piping within the factory, etc., can be used as the water supply source 75. The water supply pipe 57 connects the water supply source 75 to the water addition port 33 of the initial liquid tank 2. The flow control valve 64 is provided in the water supply pipe 57 and controls the amount of water supplied to the initial liquid tank 2.

[0036] By adding water to the initial tank 2 using the water addition device, water can be added to the nickel chloride aqueous solution that has returned to the initial tank 2 from the dissolution tank 1. The concentration of the nickel chloride aqueous solution can be adjusted by adding water. Here, stirring with the agitator 35 can make the concentration of the nickel chloride aqueous solution in the initial tank 2 uniform. Furthermore, if pure water is used as the water to be added, the contamination of the nickel chloride aqueous solution with impurities can be prevented.

[0037] A hydrochloric acid addition device is provided in the initial liquid tank 2. The hydrochloric acid addition device includes a hydrochloric acid supply source 76, a hydrochloric acid supply pipe 58, and a flow control valve 65. A tank for storing hydrochloric acid, utility piping within the factory, etc., can be used as the hydrochloric acid supply source 76. The hydrochloric acid supply pipe 58 connects the hydrochloric acid supply source 76 to the hydrochloric acid addition port 34 of the initial liquid tank 2. The flow control valve 65 is provided in the hydrochloric acid supply pipe 58 and controls the amount of hydrochloric acid supplied to the initial liquid tank 2.

[0038] By adding hydrochloric acid to the initial tank 2 using the hydrochloric acid addition device, hydrochloric acid can be added to the nickel chloride aqueous solution that has returned to the initial tank 2 from the dissolution tank 1. The pH of the nickel chloride aqueous solution can be adjusted by adding hydrochloric acid. Here, stirring with the stirrer 35 can make the pH of the nickel chloride aqueous solution in the initial tank 2 uniform. In addition, the pH of the nickel chloride aqueous solution can be measured with the pH meter 36.

[0039] As shown in Figure 1, the manufacturing equipment AA has a drainage device for discharging the generated nickel chloride aqueous solution. The drainage device has a discharge pipe 59 and a flow control valve 66. One end of the discharge pipe 59 is connected to the downstream side (dissolution tank 1 side) of the supply pipe 54 from the supply pump 72. The other end of the discharge pipe 59 is connected to the final liquid tank 4. The flow control valve 66 is provided on the discharge pipe 59. When the flow control valve 66 is opened, a portion of the nickel chloride aqueous solution flowing through the supply pipe 54 flows through the discharge pipe 59 and is guided to the final liquid tank 4.

[0040] A regulating tank 3 is provided in the middle of the discharge pipe 59. As shown in Figure 4, the regulating tank 3 has a tank body 40. The tank body 40 may be an airtight tank. The shape of the tank body 40 is not particularly limited and may be cylindrical or rectangular.

[0041] A liquid-permeable plate 41 is provided inside the tank body 40. The liquid-permeable plate 41 is installed horizontally across the lower part of the tank body 40. The internal space of the tank body 40 is divided into two spaces, upper and lower, by the liquid-permeable plate 41. As the liquid-permeable plate 41, a plate material having multiple holes or slits, such as a perforated plate or a wedge wire screen, is used. The second nickel raw material N2 is placed on top of the liquid-permeable plate 41. As a result, the adjustment tank 3 is filled with the second nickel raw material N2.

[0042] A supply port 42 is provided below the liquid passage plate 41 of the tank body 40 (preferably at the bottom). A discharge port 43 is provided above the liquid passage plate 41 of the tank body 40 (preferably at the top). The adjustment tank 3 is located in the middle of the discharge pipe 59. The discharge pipe 59 is divided into an upstream section upstream of the adjustment tank 3 and a downstream section downstream of the adjustment tank 3. The upstream section of the discharge pipe 59 connects the liquid supply pipe 54 to the supply port 42 of the adjustment tank 3. The downstream section of the discharge pipe 59 connects the discharge port 43 of the adjustment tank 3 to the final liquid tank 4. Therefore, the nickel chloride aqueous solution is supplied into the adjustment tank 3 from the supply port 42 and discharged from the discharge port 43. The nickel chloride aqueous solution that has passed through the adjustment tank 3 is stored in the final liquid tank 4.

[0043] The nickel chloride aqueous solution discharged from dissolution tank 1 contains dissolved chlorine gas. When this nickel chloride aqueous solution is passed through adjustment tank 3, the chlorine gas dissolved in the nickel chloride aqueous solution leaches out the second nickel raw material N2 in adjustment tank 3. As the chlorine gas dissolved in the nickel chloride aqueous solution is consumed in the leaching of the second nickel raw material N2, the chlorine gas can be removed from the nickel chloride aqueous solution.

[0044] In particular, if the adjustment tank 3 is configured as shown in Figure 4, the nickel chloride aqueous solution comes into contact with the second nickel raw material N2 as it flows from bottom to top inside the adjustment tank 3. This suppresses short-pass discharge, where the nickel chloride aqueous solution is discharged without sufficient contact with the second nickel raw material N2. The contact efficiency between the nickel chloride aqueous solution and the second nickel raw material N2 is good, and chlorine gas is easily removed.

[0045] The second nickel raw material N2 is not particularly limited as long as it contains nickel, but electrolytic nickel is preferred. Since electrolytic nickel is high-purity nickel, it can suppress the inclusion of impurities (components other than nickel) into the nickel chloride aqueous solution.

[0046] Dissolved chlorine gas can also be removed by placing a nickel chloride aqueous solution under negative pressure. However, the adjustment tank 3 in this embodiment does not require a device to create negative pressure, such as a vacuum pump, thus reducing equipment and operating costs. Furthermore, since dissolved chlorine gas is used in the production of the nickel chloride aqueous solution, there is no waste. Chlorine gas dissolved in the nickel chloride aqueous solution can also be removed by adsorption onto activated carbon. However, contact with activated carbon may introduce impurities into the nickel chloride aqueous solution. Alternatively, dissolved chlorine gas can be removed by adding chemicals such as reducing agents. However, adding chemicals will introduce impurities into the nickel chloride aqueous solution. In contrast to these methods, contact with electrolytic nickel can suppress the introduction of impurities into the nickel chloride aqueous solution.

[0047] (Manufacturing method) Next, a method for producing an aqueous nickel chloride solution according to one embodiment will be described.

[0048] (1) Raw material charging process In dissolution tank 1, the first nickel raw material N1 is leached with chlorine in a batch process to produce an aqueous nickel chloride solution. As shown in Figure 5 (1), at the start of the batch process, the lid 13 of dissolution tank 1 is removed and the first nickel raw material N1 is charged in through the charging port 12. The first nickel raw material N1 is stacked on top of the bamboo mat 15. After the first nickel raw material N1 is charged in, the charging port 12 is closed with the lid 13. Then, a water seal is created between the charging port 12 and the lid 13.

[0049] (2) Liquid supply process Next, as shown in (2) of Figure 5, the exhaust valve 62 of the ring collection tube 53 is opened. The liquid supply pump 72 is driven to supply the initial dissolution solution in the initial liquid tank 2 to the dissolution tank 1 (see Figure 1). Note that when the manufacturing equipment AA is started for the first time, or when there is no residual nickel chloride aqueous solution, the initial dissolution solution in the initial liquid tank 2 is water, preferably pure water. During steady operation in which batch processing is repeated, the initial dissolution solution in the initial liquid tank 2 is the nickel chloride aqueous solution produced in the previous batch processing.

[0050] The initial dissolution solution is supplied to the dissolution tank 1 from the supply port 16. As the initial dissolution solution is supplied, the liquid level in the dissolution tank 1 gradually rises. Consequently, the air in the gas phase of the dissolution tank 1 is exhausted from the collection tube 53. When the liquid level in the dissolution tank 1 reaches the height of the overflow port 17, the initial dissolution solution is discharged from the overflow port 17. At this point, most of the air present in the dissolution tank 1 is exhausted. The initial dissolution solution discharged from the overflow port 17 is returned to the initial liquid tank 2 via the overflow pipe 56 and the drain pipe 55 (see Figure 1). The supply of the initial dissolution solution from the supply port 16 continues until the batch processing is completed.

[0051] Furthermore, the small circulation pump 71 is driven to extract the liquid from the outlet 19 and inject it from the injection unit 21. This liquid circulation continues until the batch processing is completed.

[0052] (3) Depressurization process Next, as shown in (3) of Figure 6, the exhaust valve 62 of the ring collection tube 53 is closed to seal the dissolution tank 1. Then, the drain valve 63 is opened to return the initial dissolution liquid in the dissolution tank 1 to the starting liquid tank 2 via the drain pipe 55 (see Figure 1). When the drain valve 63 of the drain pipe 55 is opened, the initial dissolution liquid is discharged from the drain port 18 located at the bottom of the dissolution tank 1. As a result, the liquid level in the dissolution tank 1 gradually decreases. Since the dissolution tank 1 is sealed, the pressure in the gas phase gradually decreases as the liquid level decreases, resulting in negative pressure. In this way, after filling the dissolution tank 1 with the initial dissolution liquid, the dissolution tank 1 is sealed to lower the liquid level of the initial dissolution liquid, thereby creating negative pressure inside the dissolution tank 1.

[0053] (4) Chlorine gas supply process Simultaneously with opening the drain valve 63 of the drain pipe 55, or immediately thereafter, the supply of chlorine gas to the dissolution tank 1 is started. As shown in Figure 6 (4), the supply of chlorine gas is performed by opening the flow control valve 61 of the chlorine gas supply pipe 52. As the liquid level in the dissolution tank 1 decreases, the supply of chlorine gas creates a chlorine gas atmosphere in the gas phase of the dissolution tank 1. The supply of chlorine gas continues until the batch processing is completed.

[0054] Here, it is preferable to control the amount of chlorine gas supplied so that the pressure in the gas phase of the dissolution tank 1 remains constant at a predetermined pressure. The pressure in the gas phase of the dissolution tank 1 can be measured by a pressure gauge 22. The control device 5 obtains the measured value from the pressure gauge 22 and controls the opening of the flow control valve 61 so that the measured value remains constant at a predetermined pressure, thereby adjusting the amount of chlorine gas supplied. For example, the control device 5 performs feedback control with the pressure in the gas phase of the dissolution tank 1 as the controlled variable and the amount of chlorine gas supplied as the manipulated variable. The target value of the pressure in the gas phase of the dissolution tank 1 is set to, for example, between -1 and -3 kPa.

[0055] The liquid level in the dissolution tank 1 drops to the height of the drain port 18 and remains constant at this level. At this time, the position of the open end of the chlorine gas supply pipe 52 (the chlorine gas discharge port) may be higher than the liquid level, at the same level as the liquid level, or lower than the liquid level. In other words, the chlorine gas may be supplied directly to the gas phase in the dissolution tank 1, or it may be supplied into the liquid in the dissolution tank 1.

[0056] (5) Leaching process When the supply of chlorine gas is started, the chlorine leaching reaction of the first nickel raw material N1 begins. The gas phase in the dissolution tank 1 is filled with chlorine gas. The first nickel raw material N1 is also moistened by the liquid sprayed from the spray unit 21. As a result, the first nickel raw material N1 is covered with a liquid film under a chlorine gas atmosphere. The chlorine gas is absorbed by the liquid covering the first nickel raw material N1, the chlorine leaching reaction of the first nickel raw material N1 proceeds, and an aqueous nickel chloride solution is produced. The produced aqueous nickel chloride solution is temporarily stored at the bottom of the dissolution tank 1. A portion of this aqueous nickel chloride solution is discharged from the drain port 18 and circulates between the dissolution tank 1 and the initial liquid tank 2 via the large circulation channels 55 and 54. Another portion of the aqueous nickel chloride solution circulates through the small circulation pipe 51 and is sprayed from the spray unit 21.

[0057] The chlorine leaching reaction of the first nickel raw material N1 consumes chlorine gas, causing a decrease in the pressure of the gas phase in the dissolution tank 1. However, when controlling the supply of chlorine gas based on the pressure of the gas phase in the dissolution tank 1, an amount of chlorine gas is supplied that maintains a constant pressure in the gas phase of the dissolution tank 1. In other words, the amount of chlorine gas consumed in the chlorine leaching reaction is newly supplied.

[0058] (6) Temperature adjustment process The chlorine leaching reaction of the first nickel raw material N1 is an exothermic reaction. Therefore, if left unchecked, the temperature of the nickel chloride aqueous solution in the dissolution tank 1 will rise as the chlorine leaching reaction progresses. However, as shown in Figure 2, a heat exchanger 73 is provided in the small circulation pipe 51 through which the nickel chloride aqueous solution circulates. The heat exchanger 73 can cool the nickel chloride aqueous solution. The heat exchanger 73 adjusts the nickel chloride aqueous solution to a suitable temperature, for example, 50-60°C, from the perspective of protecting the equipment. This suppresses the temperature rise due to the heat of reaction and protects the equipment.

[0059] (7) Water addition process In the dissolution tank 1, the chlorine leaching reaction of the first nickel raw material N1 proceeds continuously. As a result, the nickel concentration in the nickel chloride aqueous solution gradually increases. Therefore, it is preferable to adjust the nickel concentration of the nickel chloride aqueous solution by adding water, preferably pure water.

[0060] In this embodiment, as shown in Figure 3, water is added to the initial tank 2. This adds water to the nickel chloride aqueous solution that has returned to the initial tank 2 from the dissolution tank 1. Here, it is preferable that the control device 5 adjusts the amount of water added to the nickel chloride aqueous solution to an amount determined based on the amount of chlorine gas supplied to the dissolution tank 1.

[0061] The ratio of the amount of chlorine gas consumed in the chlorine leaching reaction to the amount of nickel leached out is known. Therefore, the amount of water added should be proportional to the amount of chlorine gas supplied. Specifically, the control device 5 sets a target value obtained by multiplying the amount of chlorine gas supplied by a predetermined coefficient, and adjusts the opening of the flow control valve 64 of the water supply pipe 57 so that the amount of water added reaches that target value.

[0062] The nickel concentration in the nickel chloride solution is adjusted to the desired concentration by adding water. For example, the nickel concentration of the nickel chloride solution is adjusted to a predetermined value between 130 and 160 g / L. Alternatively, the nickel concentration of the nickel chloride solution may be measured periodically using a hydrometer or similar device, and the coefficient multiplied by the chlorine gas supply amount to determine the amount of water to be added may be adjusted as needed.

[0063] (8) pH adjustment process It is preferable to adjust the pH of the nickel chloride aqueous solution by adding hydrochloric acid. In this embodiment, as shown in Figure 3, hydrochloric acid is added to the initial tank 2. Here, it is preferable to adjust the pH of the nickel chloride aqueous solution to 1 to 3. The pH of the nickel chloride aqueous solution in the initial tank 2 can be measured by a pH meter 36. The control device 5 obtains the measurement value from the pH meter 36 and controls the opening of the flow control valve 65 of the hydrochloric acid supply pipe 58 so that the measurement value becomes a predetermined target value, thereby adjusting the amount of hydrochloric acid supplied. For example, the control device 5 performs feedback control with the pH of the nickel chloride aqueous solution as the controlled variable and the amount of hydrochloric acid supplied as the manipulated variable.

[0064] Maintaining the pH of the nickel chloride aqueous solution between 1 and 3 prevents the oxidation-neutralization reaction from occurring. Therefore, the formation of hydroxides and oxides through this oxidation-neutralization reaction can be suppressed.

[0065] (9) Drainage process The addition of water and hydrochloric acid causes the liquid level in the initial tank 2 to rise. The initial tank 2 then contains a nickel chloride aqueous solution with adjusted nickel concentration and pH. This adjusted nickel chloride aqueous solution is then discharged from the initial tank 2. The discharge of the nickel chloride aqueous solution is carried out by a drainage device.

[0066] As shown in Figure 1, the drainage system has a discharge pipe 59 and a flow control valve 66. Prepared nickel chloride aqueous solution flows through the supply pipe 54. By opening the flow control valve 66, a portion of the nickel chloride aqueous solution flowing through the supply pipe 54 is diverted to the discharge pipe 59 and guided to the final liquid tank 4.

[0067] Here, it is preferable for the control device 5 to adjust the discharge rate of the nickel chloride aqueous solution so that the liquid level in the initial tank 2 remains constant. Specifically, the liquid level in the initial tank 2 can be measured by the liquid level gauge 37. The control device 5 obtains the measured value from the liquid level gauge 37 and controls the opening of the flow control valve 66 of the discharge pipe 59 so that the measured value remains constant at a predetermined value, thereby adjusting the discharge rate of the nickel chloride aqueous solution. For example, the control device 5 performs feedback control with the liquid level in the initial tank 2 as the controlled amount and the discharge rate of the nickel chloride aqueous solution as the manipulated amount. By performing such control, the generated amount of nickel chloride aqueous solution can be discharged.

[0068] (10) Dechlorination gas process The nickel chloride aqueous solution discharged from the initial tank 2 is supplied to the adjustment tank 3. The adjustment tank 3 is filled with the second nickel raw material N2. Chlorine gas is dissolved in the nickel chloride aqueous solution produced in the dissolution tank 1. When this nickel chloride aqueous solution is passed through the adjustment tank 3, the nickel chloride aqueous solution comes into contact with the second nickel raw material N2, and the chlorine gas dissolved in the nickel chloride aqueous solution leaches out the second nickel raw material N2. The chlorine gas dissolved in the nickel chloride aqueous solution is consumed in the leaching of the second nickel raw material N2, thereby removing the chlorine gas from the nickel chloride aqueous solution. The nickel chloride aqueous solution, from which the dissolved chlorine gas has been removed after passing through the adjustment tank 3, is stored in the final tank 4.

[0069] The second nickel raw material N2 in the adjustment tank 3 is consumed as the nickel chloride aqueous solution is dechlorinated, and its amount gradually decreases. When the amount of the second nickel raw material N2 in the adjustment tank 3 becomes low, new second nickel raw material N2 is added to the adjustment tank 3.

[0070] Furthermore, each process from (4) the chlorine gas supply process to (10) the dechlorination gas process is carried out simultaneously. That is, as the chlorine leaching reaction of the first nickel raw material N1 progresses, the generated nickel chloride aqueous solution is adjusted, and the amount of nickel chloride aqueous solution generated is discharged.

[0071] (11) Raw material recharging process As the chlorine leaching reaction progresses, the amount of the first nickel raw material N1 in the dissolution tank 1 decreases. As the amount of the first nickel raw material N1 decreases, the contact area with the nickel chloride aqueous solution decreases, and the dissolution rate decreases. Therefore, it is preferable to terminate the batch process while a certain amount of the first nickel raw material N1 remains in the dissolution tank 1 before it is completely consumed, and to recharge the tank with the first nickel raw material N1.

[0072] Specifically, the flow control valve 61 of the chlorine gas supply pipe 52 is closed to stop the supply of chlorine gas. Next, the exhaust valve 62 of the circular collection pipe 53 is opened to degas the chlorine gas in the dissolution tank 1. The chlorine gas discharged from the circular collection pipe 53 is led to the pollution tower where pollution treatment is performed. In addition, the small circulation pump 71 is stopped to stop the circulation of the nickel chloride aqueous solution in the dissolution tank 1, and the supply of the initial dissolution solution to the dissolution tank 1 from the liquid supply pipe 54 is stopped.

[0073] After a certain period of time has elapsed since opening the exhaust valve 62 of the ring collection tube 53, degassing is completed. Then, the lid 13 of the dissolution tank 1 is removed and new first nickel raw material N1 is charged in through the charging port 12. From there, a new batch process is carried out. That is, each process from (2) the liquid feeding process to (10) the dechlorination gas process is repeatedly executed.

[0074] [Other Embodiments] The number of adjustment tanks 3 in manufacturing equipment AA is not particularly limited; there may be one or multiple. Multiple adjustment tanks 3 may be connected in series or in parallel.

[0075] Manufacturing equipment AA may have multiple dissolution tanks 1. Each of the multiple dissolution tanks 1 is connected to a single initial liquid tank 2 by a large circulation channel. Batch processing is performed in the multiple dissolution tanks 1, with the timing of charging the first nickel raw material N1 being staggered. In this way, nickel chloride aqueous solution will be produced in one of the dissolution tanks 1 throughout the operating period of manufacturing equipment AA. That is, nickel chloride aqueous solution can be produced continuously.

[0076] In the embodiment described above, the dissolution tank 1 is subjected to chlorine leaching under negative pressure, but it may also be subjected to chlorine leaching under positive pressure. In either case, it is preferable to keep the dissolution tank 1 airtight. This prevents chlorine gas from being discharged from the dissolution tank 1 while the chlorine leaching reaction is progressing. Therefore, a large-scale chlorine gas abatement device is unnecessary.

[0077] The nickel concentration of the nickel chloride aqueous solution may be adjusted by adding water to dissolution tank 1. Alternatively, the pH of the nickel chloride aqueous solution may be adjusted by adding hydrochloric acid to dissolution tank 1. In other words, the nickel chloride aqueous solution may be adjusted in dissolution tank 1, and the adjusted nickel chloride aqueous solution may be discharged from dissolution tank 1. In this case, manufacturing equipment AA does not need to have a starting tank 2. [Explanation of Symbols]

[0078] AA manufacturing equipment 1 Dissolution tank 2 Starting liquid tank 3 Adjustment tank 40 Tank body 41 Liquid passing plate 42 supply ports 43 Outlet 4. Final liquid tank 5 Control device

Claims

1. A dissolution tank for obtaining an aqueous nickel chloride solution by chlorine leaching of the first nickel raw material, The system includes a conditioning tank that brings the nickel chloride aqueous solution discharged from the dissolution tank into contact with a second nickel raw material, and leaches the second nickel raw material using chlorine gas dissolved in the nickel chloride aqueous solution. A manufacturing apparatus for nickel chloride aqueous solution characterized by the following features.

2. The adjustment tank is The tank body and The tank body is provided to divide the tank into upper and lower sections, and includes a liquid-passing plate on which the second nickel raw material is placed, The tank body has a supply port below the liquid passage plate for supplying the nickel chloride aqueous solution, The tank body comprises an outlet for discharging the nickel chloride aqueous solution from above the liquid-passing plate. The production apparatus for an aqueous nickel chloride solution according to feature 1.

3. A leaching process to obtain an aqueous nickel chloride solution by chlorine leaching of the first nickel raw material, The method includes a dechlorination step in which the nickel chloride aqueous solution is brought into contact with a second nickel raw material, and the second nickel raw material is leached out by chlorine gas dissolved in the nickel chloride aqueous solution. A method for producing an aqueous nickel chloride solution characterized by the above.

4. The second nickel raw material is electrolytic nickel. A method for producing an aqueous nickel chloride solution according to claim 3, characterized in that way.

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