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 suppress leakage of chlorine gas.SOLUTION: There is provided an apparatus for producing an aqueous solution of nickel chloride which comprises a dissolution tank 1 which is maintained at a negative pressure and into which a nickel raw material N is charged, a liquid supply device which supplies a dissolution starting liquid to the dissolution tank 1 and a chlorine gas supply device which supplies chlorine gas to the dissolution tank 1. The nickel raw material N is chlorine leached in the dissolution tank 1 to produce an aqueous solution of nickel chloride. Since the inside of the dissolution tank 1 is maintained at a negative pressure, leakage of chlorine gas from the dissolution tank 1 can be suppressed.SELECTED DRAWING: Figure 2

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. Nickel chloride is also 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 crystallization of an 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. Patent Document 3 also 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] Since chlorine gas has a pungent odor and is highly toxic, it is necessary to take measures to prevent leakage.

[0006] In view of the above circumstances, an object of the present invention is to provide a manufacturing facility and a manufacturing method for an aqueous nickel chloride solution that can suppress leakage of chlorine gas. [Means for solving the problem]

[0007] The production apparatus for an aqueous nickel chloride solution of the first invention comprises: a dissolution tank into which nickel raw materials are charged and which is airtight and maintained under negative pressure; a liquid supply device that supplies the initial dissolution solution to the dissolution tank; and a chlorine gas supply device that supplies chlorine gas to the dissolution tank. A drain pipe connected to the lower part of the dissolution tank for discharging liquid from the dissolution tank, Equipped with, The dissolution tank is filled with the initial dissolution liquid, and then, in a sealed state, the initial dissolution liquid is discharged from the drain pipe, thereby creating a negative pressure. The nickel raw material is leached with chlorine in the dissolution tank to produce an aqueous nickel chloride solution. 2nd The invention provides a manufacturing apparatus for nickel chloride aqueous solution, 1 The invention is characterized in that it includes an initial liquid tank connected to the drain pipe, and the dissolution tank is located at a higher position than the initial liquid tank. Third The invention provides a manufacturing apparatus for nickel chloride aqueous solution, 1 or 2nd The invention is characterized by comprising an overflow pipe connected to the upper part of the dissolution tank for discharging the initial dissolution liquid from the dissolution tank. 4th The invention provides a manufacturing apparatus for nickel chloride aqueous solution, The system comprises a dissolution tank into which nickel raw materials are charged and which is airtight and maintained under negative pressure; a liquid supply device that supplies the initial dissolution liquid to the dissolution tank; and a chlorine gas supply device that supplies chlorine gas to the dissolution tank. The dissolution tank comprises an inlet for charging the nickel raw material, a lid for closing the inlet, and a water seal for sealing the space between the inlet and the lid. In the dissolution tank, the nickel raw material is leached with chlorine to produce an aqueous nickel chloride solution. It is characterized by the following: Fifth The invention provides a manufacturing apparatus for nickel chloride aqueous solution, 4th The invention is characterized in that the maximum water sealing depth of the water seal portion is 408 to 510 mm. 6th The invention provides a method for producing an aqueous nickel chloride solution, comprising: a raw material charging step of charging nickel raw materials into an airtight dissolution tank; a depressurization step of creating negative pressure inside the dissolution tank; and a leaching step of obtaining an aqueous nickel chloride solution by chlorine leaching the nickel raw materials while maintaining negative pressure in the dissolution tank. In the depressurization step, after filling the dissolution tank with the initial dissolution solution, the dissolution tank is sealed and the liquid level of the initial dissolution solution is lowered to create negative pressure inside the dissolution tank. It is characterized by the following: 7th The invention provides a method for producing an aqueous nickel chloride solution. 6thThe invention is characterized in that, in the depressurization step, the pressure of the gas phase in the dissolution tank is set to -1 to -3 kPa. 8th The invention provides a method for producing an aqueous nickel chloride solution. The process comprises a raw material charging step of charging nickel raw materials into an airtight dissolution tank, a depressurization step of creating negative pressure inside the dissolution tank, and a leaching step of obtaining an aqueous nickel chloride solution by chlorine leaching the nickel raw materials while maintaining negative pressure in the dissolution tank. The nickel raw material is characterized by being electrolytic nickel. [Effects of the Invention]

[0008] 1 According to the invention, the water head of the initial dissolution solution is used to create negative pressure inside the dissolution tank, making it efficient. Furthermore, negative pressure can be easily created without the need for depressurization devices such as vacuum pumps. 2nd According to the invention, since a height difference is provided between the dissolution tank and the initial liquid tank, the initial liquid is discharged from the dissolution tank by the water head of the initial liquid, making it possible to create negative pressure more efficiently and reliably. Third According to the invention, the dissolution tank can be filled with dissolution liquid by supplying the dissolution liquid to the dissolution tank until it is discharged from the overflow pipe. 4th According to the invention, even if the pressure inside the dissolution tank drops excessively, outside air flows into the dissolution tank due to the water seal breaking, causing the pressure to rise. Therefore, damage to the dissolution tank due to excessive negative pressure can be suppressed. Fifth According to the invention, the negative pressure inside the dissolution tank can be limited to -4 to -5 kPa, thereby suppressing damage to the dissolution tank due to excessive negative pressure. 6th According to the invention, the water head of the initial dissolution solution is used to create negative pressure inside the dissolution tank, making it efficient. Furthermore, negative pressure can be easily created without the need for depressurization devices such as vacuum pumps. 7th According to the invention, the inside of the dissolution tank is kept at an appropriate negative pressure, making the depressurization operation easy. Furthermore, damage to the dissolution tank due to excessive negative pressure can be suppressed. 8th According to the invention, a highly pure aqueous solution of nickel chloride can be obtained. [Brief explanation of the drawing]

[0009] [Figure 1] It is an overall configuration diagram of manufacturing equipment according to an embodiment. [Figure 2] It is a longitudinal sectional view of the dissolution tank. [Figure 3] Figure (A) is a longitudinal sectional view around the charging port. Figure (B) is a plan view around the charging port. [Figure 4] It is a longitudinal sectional view of the starting liquid tank. [Figure 5] It is an explanatory diagram showing the state of the dissolution tank in the (1) raw material charging step and the (2) liquid supply step. [Figure 6] It is an explanatory diagram showing the state of the dissolution tank in the (3) decompression step and the (4) chlorine gas supply step.

Mode for Carrying Out the Invention

[0010] Next, embodiments of the present invention will be described based on the drawings. (Manufacturing Equipment) The manufacturing equipment for an aqueous nickel chloride solution according to an embodiment of the present invention is equipment for producing an aqueous nickel chloride 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 aqueous nickel chloride solution can be obtained without performing special purification treatment.

[0011] Electrolytic nickel can be produced, for example, by the wet smelting of nickel. In the wet smelting of nickel, raw materials such as nickel matte and nickel-cobalt mixed sulfide are chlorine-leached. Purification treatment for removing impurities from the leachate is performed to obtain an aqueous nickel chloride solution. Electrolytic nickel is obtained by electrolytic extraction using the aqueous nickel chloride solution as an electrolyte.

[0012] To increase dissolution efficiency, smaller electrolytic nickel pieces are preferable. For example, it is preferable to use plate-shaped electrolytic nickel cut to dimensions of 100 mm x 100 mm or less. Button-shaped electrolytic nickel may also be used. The smaller the dimensions of the electrolytic nickel, the larger the contact area with the nickel chloride aqueous solution, thus allowing chlorine leaching to proceed more efficiently.

[0013] As shown in Figure 1, the manufacturing equipment AA of this embodiment includes a dissolution tank 1, a starting tank 2, a regulating tank 3, and a final tank 4. Furthermore, the manufacturing equipment AA has a control device 5 that acquires measurement values ​​from various measuring instruments and controls the operation of various valves, pumps, etc. A computer such as a PLC can be used as the control device 5.

[0014] As shown in Figure 2, the dissolution tank 1 is a tank for chlorine leaching of nickel raw material N. The dissolution tank 1 has a tank body 10. The tank body 10 is an airtight tank. The shape of the tank body 10 is not particularly limited and may be cylindrical or rectangular.

[0015] An inlet 12 is provided in the center of the top plate of the tank body 10. Nickel raw material N is charged into the tank body 10 through the inlet 12. The inlet 12 is closed by a lid 13. A water seal is also provided between the inlet 12 and the lid 13. Therefore, by closing the inlet 12 with the lid 13 and creating a water seal, the tank body 10 can be made airtight.

[0016] As shown in Figures 3(A) and 3(B), the charging port 12 is made up of a cylindrical member erected on the upper surface of the top plate 11. The lid 13 is a cylindrical member with its upper end closed. The inner diameter of the cylindrical part of the lid 13 is slightly larger than the outer diameter of the cylindrical part of the charging port 12. Also, the height dimension of the cylindrical part of the lid 13 is slightly larger than the height dimension of the cylindrical part of the charging port 12.

[0017] The area around the charging port 12 is surrounded by a wall 14 erected on the upper surface of the top plate 11. Seal water W is stored in the area between the wall 14 and the cylindrical part of the charging port 12. When the charging port 12 is closed with the lid 13, the gap between the cylindrical part of the charging port 12 and the cylindrical part of the lid 13 is sealed by the seal water W. This creates a water seal between the charging port 12 and the lid 13. In other words, the water seal is formed by the cylindrical part of the charging port 12, the cylindrical part of the lid 13, and the wall 14.

[0018] As described later, while the nickel raw material N is being treated with chlorine leaching, the inside of the dissolution tank 1 is maintained under negative pressure. Therefore, the liquid level between the cylindrical part of the inlet 12 and the cylindrical part of the lid 13 is higher than the liquid level outside the lid 13, which is open to the atmosphere. For example, if the atmospheric pressure inside the dissolution tank 1 is -2 kPa (= -204 mmH2O), the difference in liquid levels will be 204 mm.

[0019] If the internal pressure of the dissolution tank 1 drops excessively below the set pressure, the sealing water W is drawn into the dissolution tank 1, ultimately leading to a seal failure. This seal failure allows outside air to flow into the dissolution tank 1, increasing the pressure. Therefore, damage to the dissolution tank 1 due to excessive negative pressure can be suppressed.

[0020] The pressure at which the water seal breaks can be set by the maximum water seal depth of the water seal. Here, the maximum water seal depth is the maximum depth that the water seal can take. The maximum water seal depth is determined by the structure of the water seal. In this embodiment, the height of the cylindrical part of the inlet 12 (the height of the upper edge of the cylindrical part with respect to the top surface of the top plate 11) is the maximum water seal depth D.

[0021] For example, to limit the negative pressure inside the dissolution tank 1 to -4kPa (=-408mmH2O), the maximum sealing depth D should be 408mm. To limit the negative pressure inside the dissolution tank 1 to -5kPa (=-510mmH2O), the maximum sealing depth D should be 510mm. Depending on the pressure resistance performance of the dissolution tank 1, the maximum sealing depth D of the water seal is preferably 408 to 510mm. This allows the negative pressure inside the dissolution tank 1 to be limited to -4 to -5kPa, thereby suppressing damage to the dissolution tank 1 due to excessive negative pressure.

[0022] As shown in Figure 2, a slatted plate 15 is provided inside the tank body 10. The slatted plate 15 is installed horizontally so as to cross the tank body 10 near the center of the top and bottom. The internal space of the tank body 10 is divided into two spaces, upper and lower, by the slatted plate 15. As the slatted plate 15, a plate material having multiple holes or slits, such as a perforated plate or a wedge wire screen, is used. The nickel raw material N charged from the charging port 12 is placed on the slatted plate 15. Meanwhile, the liquid passes through the slatted plate 15 and flows down from the upper space to the lower space of the tank body 10.

[0023] A liquid inlet 16 is provided on the top plate of the tank body 10. The liquid inlet 16 is connected to a liquid supply device. The initial dissolving solution supplied from the liquid supply device flows into the tank body 10 through the liquid inlet 16. Details of the liquid supply device will be described later.

[0024] The side wall of the tank body 10 is provided with an overflow port 17 at the top and a drain port 18 at the bottom. The overflow port 17 is located above the slat plate 15 and close to the top of the tank body 10. On the other hand, the drain port 18 is located below the slat plate 15 and close to the slat plate 15. Both the overflow port 17 and the drain port 18 are used to drain the liquid from inside the tank body 10.

[0025] An outlet 19 is provided on the side wall of the tank body 10. The outlet 19 is located below the drain port 18 and close to the bottom of the tank body 10. A return port 20 is provided on the top plate of the tank body 10.

[0026] The outlet 19 and the return port 20 are connected by a small circulation pipe 51. A small circulation pump 71 is installed 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, liquid is drawn out from the bottom of the tank body 10 and returned to the top of the tank body 10.

[0027] 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.

[0028] 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 nickel raw material N.

[0029] 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 charging nickel raw material N.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The gas phase within the dissolution tank 1 is filled with chlorine gas supplied from the chlorine gas supply pipe 52. The nickel raw material N is also moistened by the liquid sprayed from the spray unit 21. This results in the nickel raw material N being covered with a liquid film under a chlorine gas atmosphere. The chlorine gas is absorbed by the liquid covering the nickel raw material N, and the chlorine leaching reaction of the nickel raw material N proceeds, generating an aqueous nickel chloride solution. In this way, the nickel raw material N 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.

[0034] As shown in Figure 4, 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The dissolution tank 1 is mounted on a base 24. The dissolution tank 1 is positioned higher than the initial liquid tank 2 by the height of the base 24. Here, both the overflow port 17 and the drain port 18 of the dissolution tank 1 are located above the liquid level in the initial liquid tank 2. Therefore, the liquid discharged from the overflow port 17 and the drain port 18 flows naturally into the initial liquid tank 2 due to its water head.

[0040] As shown in Figure 4, 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] A conditioning tank 3 is provided in the middle of the discharge pipe 59. The conditioning tank 3 is filled with nickel raw material. 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 conditioning tank 3, the nickel raw material in the conditioning tank 3 is leached out by the chlorine gas dissolved in the nickel chloride aqueous solution. As the chlorine gas dissolved in the nickel chloride aqueous solution is consumed in the leaching of the nickel raw material, the chlorine gas can be removed from the nickel chloride aqueous solution. In this way, the contamination of the nickel chloride aqueous solution with impurities can be suppressed compared to cases where dissolved chlorine gas is removed using chemicals such as reducing agents. It is preferable to use electrolytic nickel as the nickel raw material to fill the conditioning tank 3. Since electrolytic nickel is high-purity nickel, the contamination of the nickel chloride aqueous solution with impurities can be further suppressed. The nickel chloride aqueous solution that has passed through the conditioning tank 3 is stored in the final liquid tank 4.

[0046] (Manufacturing method) Next, we will explain the method for producing an aqueous nickel chloride solution using manufacturing equipment AA.

[0047] (1) Raw material charging process In dissolution tank 1, nickel raw material N 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 nickel raw material N is charged in through the charging port 12. The nickel raw material N is piled up on the bamboo plate 15. After the nickel raw material N 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.

[0048] (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.

[0049] 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.

[0050] By supplying the dissolution starter liquid to the dissolution tank 1 until it is discharged from the overflow pipe 56, the dissolution tank 1 can be filled with the dissolution starter liquid. Furthermore, since the tank can be filled with the dissolution starter liquid at the same liquid level, the reproducibility of the operation in the depressurization process described later can be increased.

[0051] Furthermore, a small circulation pump 71 is driven to extract 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] As mentioned above, there is a height difference between the dissolution tank 1 and the initial liquid tank 2. Therefore, the initial liquid is discharged from the dissolution tank 1 by the water head of the initial liquid. Since the water head of the initial liquid is used to create negative pressure inside the dissolution tank 1, it is efficient. Furthermore, negative pressure can be easily created without the need for vacuum pumps or other depressurization devices.

[0054] (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.

[0055] Here, the amount of chlorine gas supplied is controlled to a level at which 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 to adjust the amount of chlorine gas supplied, so that the measured value remains constant at a predetermined pressure. 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 for the pressure in the gas phase of the dissolution tank 1 is set, for example, between -1 and -3 kPa. Since the inside of the dissolution tank 1 is kept at an appropriate negative pressure, depressurization operations are easy. In addition, damage to the dissolution tank 1 due to excessive negative pressure can be suppressed.

[0056] 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.

[0057] (5) Leaching process When the supply of chlorine gas is started, the chlorine leaching reaction of nickel raw material N begins. The gas phase inside the dissolution tank 1 is filled with chlorine gas. In addition, the nickel raw material N is moistened by the liquid sprayed from the spray unit 21. As a result, the nickel raw material N is covered with a liquid film under a chlorine gas atmosphere. The chlorine gas is absorbed by the liquid covering the nickel raw material N, the chlorine leaching reaction of nickel raw material N proceeds, and an aqueous nickel chloride solution is produced. The chlorine leaching of nickel raw material N is carried out while the dissolution tank 1 is maintained under negative pressure. Since the inside of the dissolution tank 1 is maintained under negative pressure, leakage of chlorine gas from the dissolution tank 1 can be suppressed.

[0058] The generated nickel chloride aqueous solution is temporarily stored at the bottom of the dissolution tank 1. A portion of this nickel chloride aqueous 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 nickel chloride aqueous solution circulates through the small circulation pipe 51 and is sprayed from the spray unit 21.

[0059] The chlorine leaching reaction of nickel raw material N consumes chlorine gas, causing a decrease in the pressure of the gas phase in dissolution tank 1. However, the supply of chlorine gas is controlled to maintain a constant pressure in the gas phase of dissolution tank 1. In other words, the amount of chlorine gas consumed in the chlorine leaching reaction is replaced with a new supply.

[0060] (6) Temperature adjustment process The chlorine leaching reaction of nickel raw material N 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.

[0061] (7) Water addition process In the dissolution tank 1, the chlorine leaching reaction of nickel raw material N 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.

[0062] In this embodiment, as shown in Figure 4, 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.

[0063] 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.

[0064] 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.

[0065] (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 4, 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.

[0066] 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.

[0067] (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.

[0068] 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.

[0069] 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.

[0070] (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 nickel raw material. 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 and the nickel raw material come into contact, and the nickel raw material is leached out by the chlorine gas dissolved in the nickel chloride aqueous solution. The chlorine gas dissolved in the nickel chloride aqueous solution is consumed in the leaching of the nickel raw material, thus 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.

[0071] 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 nickel raw material N progresses, the generated nickel chloride aqueous solution is adjusted, and the amount of nickel chloride aqueous solution generated is discharged.

[0072] (11) Raw material recharging process As the chlorine leaching reaction progresses, the amount of nickel raw material N in the dissolution tank 1 decreases. As the amount of nickel raw material N 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 nickel raw material N remains in the dissolution tank 1 before it is completely consumed, and to recharge the nickel raw material N.

[0073] 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.

[0074] 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 nickel raw material N 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.

[0075] [Other Embodiments] In the embodiment described above, the nickel chloride aqueous solution in the dissolution tank 1 is circulated through the small circulation pipe 51 and injected from the injection unit 21 onto the nickel raw material N. Alternatively, the nickel chloride aqueous solution circulating in the large circulation channel between the dissolution tank 1 and the initial liquid tank 2 may be injected from the injection unit 21. In this case, the small circulation pipe 51 may be omitted. Furthermore, the temperature of the nickel chloride aqueous solution may be controlled by a heat exchanger provided in the large circulation channel.

[0076] 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 nickel raw material N 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.

[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, the initial tank 2 may be omitted. [Explanation of symbols]

[0078] AA manufacturing equipment 1 Dissolution tank 12 Charging port 13 Lid 14 Wall 15 Screen board 2 Starting liquid tank 3 Adjustment tank 4. Final liquid tank 5 Control device 52 Chlorine gas supply pipe 54 Liquid supply pipe 55 Drainage pipe 56 Overflow pipe

Claims

1. A melting tank containing nickel raw materials and maintained under negative pressure, A liquid supply device that supplies the initial dissolution solution to the dissolution tank, A chlorine gas supply device that supplies chlorine gas to the dissolution tank, The dissolution tank is connected to the lower part of the dissolution tank and includes a drain pipe for discharging liquid from the dissolution tank, The dissolution tank is filled with the initial dissolution liquid, and then, in a sealed state, the initial dissolution liquid is discharged from the drain pipe, thereby creating a negative pressure. In the aforementioned dissolution tank, the nickel raw material is leached with chlorine to produce an aqueous nickel chloride solution. A manufacturing apparatus for nickel chloride aqueous solution characterized by the following features.

2. The system includes a starting tank connected to the aforementioned drain pipe, The dissolution tank is located at a higher elevation than the initial liquid tank. The production apparatus for an aqueous nickel chloride solution according to feature 1.

3. It is connected to the upper part of the dissolution tank and includes an overflow pipe for discharging the initial dissolution liquid from the dissolution tank, The production apparatus for an aqueous nickel chloride solution according to feature 1.

4. A melting tank having airtightness into which nickel raw material is charged and maintained under negative pressure, A liquid supply device that supplies the initial dissolution solution to the dissolution tank, The system includes a chlorine gas supply device that supplies chlorine gas to the dissolution tank, The aforementioned dissolution tank is An inlet for charging the aforementioned nickel raw material, A cover that closes the aforementioned charging port, It includes a water seal portion that seals the space between the inlet and the lid, In the dissolution tank, the nickel raw material is leached with chlorine to produce an aqueous nickel chloride solution. A manufacturing apparatus for nickel chloride aqueous solution characterized by the following features.

5. The maximum water sealing depth of the water seal is 408 to 510 mm. The production equipment for an aqueous nickel chloride solution according to feature 4.

6. A raw material charging process involves charging nickel raw materials into an airtight melting tank, A depressurization step to create a negative pressure inside the dissolution tank, The process includes a leaching step in which the nickel raw material is leached with chlorine while the dissolution tank is maintained under negative pressure to obtain an aqueous nickel chloride solution, In the depressurization step, after filling the dissolution tank with the initial dissolution solution, the dissolution tank is sealed and the liquid level of the initial dissolution solution is lowered to create negative pressure inside the dissolution tank. A method for producing an aqueous nickel chloride solution characterized by the above.

7. In the depressurization process, the pressure in the gas phase of the dissolution tank is set to -1 to -3 kPa. A method for producing an aqueous nickel chloride solution according to claim 6.

8. A raw material charging step of charging nickel raw materials into an airtight dissolution tank, A depressurization step to create a negative pressure inside the dissolution tank, The process includes a leaching step in which the nickel raw material is leached with chlorine while the dissolution tank is maintained under negative pressure to obtain an aqueous nickel chloride solution, The aforementioned nickel raw material is electrolytic nickel. A method for producing an aqueous nickel chloride solution characterized by the above.

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