JP5673471B2 - Method for removing copper ions in aqueous nickel chloride solution and method for producing electronickel - Google Patents

Description

  The present invention relates to a method for removing copper ions from a nickel chloride aqueous solution and a method for producing electrical nickel. More specifically, the present invention relates to copper from a nickel chloride aqueous solution obtained by leaching, for example, nickel sulfide obtained from nickel oxide ore. The present invention relates to a method for removing copper ions in an aqueous nickel chloride solution and a method for producing the electric nickel in a method for producing electric nickel which is fixedly removed and produced by electrolytic collection.

  The step of removing copper ions, which are impurities, from the aqueous nickel chloride solution is an important step in the manufacturing process of electrolytic nickel. For example, in the process of electrolytically collecting high-purity electrical nickel from a leachate (nickel chloride aqueous solution) obtained by leaching nickel raw materials such as nickel sulfide, the amount of copper contained in the nickel chloride aqueous solution is 0.1 g / L or less The electrolytic solution is obtained by a method of removing the low concentration region of the steel and further removing the remaining elements such as iron and cobalt.

  Methods for removing copper ions from an aqueous nickel chloride solution include a method of removing copper ions as hydroxide by adjusting the pH of the aqueous solution, a method of selectively removing copper by electrolysis or solvent extraction, and copper by addition of sulfide. And a method of removing as a sulfide. However, in removing copper to a low concentration range by these methods, there are the following problems industrially.

  For example, in the method of removing copper ions as a hydroxide, the generated hydroxide becomes fine, so that there is a concern that a filtration failure may occur in a solid-liquid separation process in a subsequent process. Also, with this method, it is difficult to selectively remove copper, and nickel, iron, etc. are co-precipitated, so if you try to remove the copper concentration in the aqueous solution to a range where there is no problem in the electrowinning process, There is a problem of increased loss.

  In addition, in the electrolytic method, copper has a lower ionization tendency than nickel, so it is possible to selectively remove copper. This increases the recovery loss of nickel. In addition, this electrolysis method requires a large facility, and operation costs such as electric power are excessive. Further, in the solvent extraction method, copper can be selectively removed, but since the entire amount of the aqueous solution flowing in the process needs to be treated, the equipment becomes large and the operation cost increases.

  In terms of selective removal of copper, a method using a sulfurizing agent such as hydrogen sulfide is extremely effective. However, since the copper sulfide generated at this time generally has a fine particle size, filtration failure occurs in the solid-liquid separation process, which often becomes a bottleneck of the process.

  On the other hand, it is possible to selectively remove copper to a low concentration even by a method of adding nickel matte, which is a nickel raw material, as a sulfurizing agent (see, for example, Patent Documents 1 and 2). However, since the nickel mat is manufactured by dry processing, the cost is very high in small-scale manufacturing. Moreover, when it purchases, it is expensive and there exists a problem from a cost viewpoint when utilizing as a copper removal agent. In addition, there is a method of adding nickel sulfide (NiS) produced by a wet process as a sulfiding agent. However, nickel sulfide is low in reactivity as a sulfiding agent used for copper removal, so copper ions in an aqueous nickel chloride solution are reduced. It is difficult to reduce the concentration.

Japanese Patent Laid-Open No. 02-145731 JP 2007-191769 A

  The present invention has been proposed in view of the above situation, and in a method of immobilizing and removing copper ions from a nickel chloride aqueous solution containing copper ions, the copper concentration in the nickel chloride aqueous solution is, for example, 0.1 g / A copper ion removal method capable of improving the filterability of sulfides by reducing the generated sulfides at the same time as reducing to a low concentration range of L or less, and electric nickel to which the copper ion removal method is applied An object is to provide a manufacturing method.

  As a result of intensive studies to achieve the above-described object, the present inventors have added nickel sulfide to a nickel chloride aqueous solution containing copper to reduce copper ions, and then added hydrogen sulfide to form copper. By fixing and removing the ions, the copper concentration in the nickel chloride aqueous solution can be reduced to a low concentration range, and the added nickel sulfide acts as a filter aid to suppress the refinement of the sulfide. It discovered that filterability could be improved and completed this invention.

  That is, the method for removing copper ions in an aqueous nickel chloride solution according to the present invention was obtained by adding nickel sulfide to an aqueous nickel chloride solution containing copper ions and reducing the copper ions and the reducing step. Supplying hydrogen sulfide to the slurry and immobilizing the reduced copper ions as copper sulfide; and a solid-liquid separation step of solid-liquid separating the slurry obtained through the copper ion immobilization step. It is characterized by having.

  The method for producing electronickel according to the present invention is a method for producing electronickel by removing copper ions from an aqueous solution of nickel chloride containing copper obtained by leaching nickel sulfide with chlorine and producing electronickel by electrowinning. And adding nickel sulfide to the nickel chloride aqueous solution containing the copper ions, reducing the copper ions, supplying hydrogen sulfide to the slurry obtained through the reduction step, and reducing the copper ions. It includes a cementation step having a copper ion immobilization step for immobilizing selenium as copper sulfide and a solid-liquid separation step for solid-liquid separation of the slurry obtained through the copper ion immobilization step.

  According to the present invention, the copper concentration in the nickel chloride aqueous solution can be reduced to a low concentration range, and at the same time, the refinement of copper sulfide generated can be suppressed and the filterability can be improved. In addition, by producing electrolytic nickel using the nickel chloride aqueous solution from which copper ions are removed effectively and efficiently by improving the filterability in this way, it is possible to produce high-quality electrical nickel free of impurities. .

It is process drawing of the electrical nickel manufacturing process to which the copper ion removal method which concerns on this Embodiment is applied. It is process drawing of a cementation process.

  Hereinafter, specific embodiments of a method for removing copper ions in an aqueous nickel chloride solution according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present invention.

  The method for removing copper ions in a nickel chloride aqueous solution according to the present embodiment (hereinafter also referred to as copper ion removal method) is a chloride obtained by leaching a metal sulfide containing copper such as nickel sulfide. It removes copper ions from an aqueous nickel solution. The nickel chloride aqueous solution from which the copper ions have been removed in this way becomes, for example, an electrolytic solution for an electrolytic nickel production process, and is used for electrolytic deposition of electrical nickel.

  Specifically, the copper ion removal method according to the present embodiment was obtained through a reduction step of adding nickel sulfide to a nickel chloride aqueous solution containing copper ions to reduce copper ions in the aqueous solution, and a reduction step. It has a copper ion immobilization step of supplying hydrogen sulfide to the slurry and immobilizing copper ions as copper sulfide, and a solid-liquid separation step of solid-liquid separating the slurry obtained through the copper ion immobilization step.

  According to this copper ion removal method, the copper concentration in the nickel chloride aqueous solution can be effectively reduced to a low concentration range of, for example, about 0.1 g / L, and at the same time, the copper ions are immobilized and generated. Refinement of copper sulfide can be suppressed to improve filterability, and copper ions can be effectively and efficiently removed from the aqueous nickel chloride solution. Further, by producing electrolytic nickel using the nickel chloride aqueous solution from which copper ions have been removed in this way, it is possible to produce high-quality electrical nickel free of impurities.

  Hereinafter, the copper ion removing method according to the present embodiment will be described more specifically based on a specific example in which the method for producing electrolytic nickel is applied.

  FIG. 1 is a process diagram of a manufacturing process for electrolytic nickel. As shown in FIG. 1, the nickel manufacturing process uses nickel sulfide as a raw material to leaching metals such as nickel into chlorine and produces a nickel chloride aqueous solution (copper-containing nickel chloride aqueous solution) containing copper ions as a chlorine leaching solution. A chlorine leaching step S1, a cementation step S2 for fixing and removing copper ions from the copper-containing nickel chloride aqueous solution obtained in the chlorine leaching step S1, and a liquid purification step for removing impurities other than nickel from the cementation final solution S3 and electrolysis process S4 which obtains electric nickel by the electrowinning method from the nickel chloride aqueous solution obtained through liquid purification process S3.

<Chlorine leaching process>
In the chlorine leaching step S1, for example, a metal sulfide containing copper such as nickel sulfide 10 manufactured by wet smelting from nickel oxide ore is used as a raw material, and a metal such as nickel is leached with chlorine. Specifically, the chlorine gas recovered in the electrolysis step S4 together with the cementation residue after the cementation step S2 described later is used to leach metals such as nickel in the metal sulfide raw material such as nickel sulfide to obtain a chlorine leaching solution. Of copper-containing nickel chloride aqueous solution. Here, the metal sulfide raw material such as nickel sulfide is repulped and slurried with an aqueous solution of nickel chloride obtained in the electrolysis process.

Specifically, in the chlorine leaching step S1, for example, reactions shown in the following formulas (1) to (3) occur.
Cl ₂ + 2Cu ⁺ → 2Cl ⁻ + 2Cu ²⁺ (1)
NiS + 2Cu ²⁺ → Ni ²⁺ + S ⁰ + 2Cu ⁺ (2)
Cu ₂ S + 2Cu ²⁺ → 4Cu ⁺ + S ⁰ (3)

  That is, in the chlorine leaching step S1, when nickel sulfide as a raw material is fed, metal components such as nickel sulfide and copper sulfide contained in the nickel sulfide are converted into divalent copper ions oxidized by chlorine gas. By oxidative leaching, an aqueous nickel chloride solution containing copper ions as a chlorine leaching solution is generated. The nickel chloride aqueous solution generated in the chlorine leaching step S1 is processed in the subsequent cementation step S2, and the copper ions in the aqueous solution are fixed and removed. On the other hand, in this chlorine leaching step S1, a chlorine leaching residue mainly containing sulfur remains in the solid phase.

<Cementation process>
In the cementation step S2, the copper ions are fixed and removed from the nickel chloride aqueous solution containing the copper ions which are the chlorine leaching solution generated in the chlorine leaching step S1. In the electrolytic nickel smelting process, copper contained in the nickel chloride aqueous solution to be subjected to nickel electrowinning becomes an impurity. Therefore, it is possible to produce good quality nickel by effectively removing copper from the nickel chloride aqueous solution.

  In this embodiment, in this cementation step S2, as shown in FIG. 2, a reduction step S21 in which nickel sulfide is added to a nickel chloride aqueous solution containing copper ions to reduce copper ions in the aqueous solution, and a reduction step S21. The copper ion immobilization step S22 in which hydrogen sulfide is added to the slurry obtained through the above steps to immobilize copper ions as copper sulfide, and the slurry obtained through the copper ion immobilization step S22 is subjected to solid-liquid separation. Step S23.

  In addition, the cementation final liquid obtained through cementation process S2 which consists of each process (S21-S23) mentioned above is sent to liquid purification process S3, and other impurities, such as iron and zinc, are removed. On the other hand, the cementation residue containing the copper immobilized and removed in the cementation step S2 is sent again to the chlorine leaching step S1, and is leached with a new nickel sulfide raw material.

(Reduction process)
First, in the reduction step S21, the copper ions in the nickel chloride aqueous solution containing copper generated in the chlorine leaching step S1 are reduced. At this time, in this embodiment, nickel sulfide (NiS) is added for reduction treatment.

Specifically, in this reduction step S21, for example, reactions shown in the following (4) to (5) occur.
4NiS + 2Cu ²⁺ → Ni ²⁺ + Ni ₃ S ₄ + 2Cu ⁺ (4)
NiS + 2Cu ⁺ → Ni ²⁺ + Cu ₂ S (5)

  As shown in the above formula (4), in the reduction step S21, nickel sulfide is added to the nickel chloride aqueous solution generated in the chlorine leaching step S1, so that the nickel sulfide is divalent copper in the nickel chloride aqueous solution. Ions are reduced to monovalent copper ions. The copper ions thus reduced are fixed as copper sulfide by the hydrogen sulfide added in the subsequent copper ion fixing step S22.

  That is, in the cementation step S2 according to the present embodiment, copper ions are reduced by making the best use of the reducing power of nickel sulfide in the reduction step S21, and copper sulfide is removed in the subsequent copper ion immobilization step S22. Let it form. Thereby, in the copper ion immobilization step S22, copper sulfide which is an immobilization product of copper ions is formed effectively and efficiently, and the amount of hydrogen sulfide to be added can be reduced.

  Further, in this embodiment, by adding nickel sulfide to the nickel chloride aqueous solution, this nickel sulfide can act as a filter aid when forming copper sulfide. That is, in forming the copper sulfide, the added nickel sulfide can act as a so-called seed crystal. Thereby, it is possible to suppress the copper sulfide from being refined, improve the filterability of the sulfide, and effectively separate and remove copper from the nickel chloride aqueous solution.

  Here, the nickel sulfide to be added is not particularly limited, but it is preferable to use a nickel sulfide having a median diameter (D50) of 20 μm or more. By adding nickel sulfide having a median diameter of 20 μm or more, nickel sulfide can sufficiently act as a so-called seed crystal, and the particle diameter of the formed copper sulfide can be increased, and the filterability is more effective. Can be improved. More preferably, nickel sulfide having a median diameter of 30 μm or more is added. Thereby, the particle size of copper sulfide can be further increased, the filterability is further improved, and copper can be efficiently removed. The upper limit of the particle size of nickel sulfide is not particularly limited, but is preferably 100 μm or less from the viewpoint of reduction efficiency.

  The method for adjusting the particle size of nickel sulfide is not particularly limited, but can be adjusted by wet pulverization using, for example, a tower mill or a bead mill.

  The addition amount of nickel sulfide is not particularly limited, and is added so as to be excessively large relative to the amount of copper in the nickel chloride aqueous solution.

  Although it does not specifically limit as temperature conditions in reduction process S21, It is preferable to set it as 80-110 degreeC, and it is more preferable to set it as 90-95 degreeC especially. By setting the temperature condition to 80 ° C. or higher, the reduction reaction of the copper ions in the nickel chloride aqueous solution can be efficiently advanced, and the copper ion immobilization efficiency in the copper ion immobilization step S22 described later is improved. be able to. When the temperature condition is higher than 110 ° C., although the reduction efficiency of copper ions in the nickel chloride aqueous solution is improved, the equipment cost due to the heat resistance specification and the operation cost due to the increase in the amount of steam are required, and the efficient operation cannot be performed.

  In addition, the nickel chloride aqueous solution used in the reduction step S21 and generated in the chlorine leaching step S1 is not particularly limited and can be applied in any composition state. For example, a nickel concentration of 150 to 270 g / L, a copper concentration of 20 to 40 g / L, and a pH of 0.5 to 2.0 can be used. Moreover, as a form of the copper ion in the nickel chloride aqueous solution, for example, a divalent copper ion ratio of 60 to 90% and a monovalent copper ion ratio of 10 to 40% can be used.

  Thus, in the reduction step S21, nickel sulfide is added to the nickel chloride aqueous solution to reduce the divalent copper ions in the aqueous solution to monovalent copper ions. Thereby, in the copper ion immobilization step S22 of the next step, the reaction using reduced monovalent copper ions as sulfides efficiently proceeds, so that the copper ions are effectively immobilized and removed. In addition, the amount of expensive hydrogen sulfide added in the next step can be reduced, and an efficient copper removal treatment can be performed.

  Further, in the present embodiment, the nickel sulfide added in the reduction step S21 can act as a filter aid when immobilizing copper ions, so that a precipitate of copper sulfide is formed based on the nickel sulfide. It becomes formed, and it can suppress that the copper sulfide formed becomes fine and can improve filterability.

The nickel sulfide added in the reduction step S21 has a low reactivity as a sulfiding agent, and although it is difficult to remove copper ions in the nickel chloride aqueous solution to a low concentration, it is represented by the above formula (5). The reaction of immobilizing such monovalent copper ions as copper sulfide (Cu ₂ S) can also be slightly caused. Therefore, by adding nickel sulfide, not only in the copper ion fixing step S22 of the next step, but also in the reduction step S21, it can be fixed as copper sulfide, and also in this respect, it is expensive to add in the next step. The amount of hydrogen sulfide used can be reduced, and an efficient copper removal treatment can be performed.

(Copper ion immobilization process)
Next, in the copper ion fixing step S22, hydrogen sulfide (H ₂ S) is supplied, and the copper ions reduced in the reducing step S21 are fixed as copper sulfide. At this time, in the present embodiment, it is important to supply hydrogen sulfide directly to the slurry obtained through the reduction step S21. That is, hydrogen sulfide is supplied in a state where nickel sulfide remains in the slurry without performing a process such as solid-liquid separation on the slurry obtained in the reduction step S21.

Specifically, in this copper ion immobilization step S22, for example, reactions represented by the following formulas (6) and (7) occur.
H ₂ S + 2Cu ⁺ → 2H ⁺ + Cu ₂ S (6)
2Cu ⁺ + S + H ₂ S → 2CuS + 2H ⁺ (7)

  As shown in the above formulas (6) and (7), the copper ion immobilization step S22 was obtained because the divalent copper ions in the nickel chloride aqueous solution were reduced to monovalent copper ions by the reduction step S21. By supplying hydrogen sulfide to the slurry, the reaction in which hydrogen sulfide becomes a sulfur source to form copper sulfide effectively proceeds. Thereby, the copper contained in the nickel chloride aqueous solution can be fixed as copper sulfide. And the copper sulfide deposit formed by immobilizing copper can be separated and removed from the nickel chloride aqueous solution by performing a solid-liquid separation process in the next solid-liquid separation step S23.

  The supplied hydrogen sulfide is a strong reducing agent. By fixing copper ions with this hydrogen sulfide, the copper concentration in the nickel chloride aqueous solution can be reduced to a low concentration range of 0.1 g / L or less. it can.

  Since the hydrogen sulfide supplied to the slurry is a gas at room temperature, it is supplied as hydrogen sulfide gas. As the hydrogen sulfide gas, for example, a hydrogen sulfide gas synthesis facility attached to an electric nickel production plant and supplied from the synthesis facility can be used. Moreover, the density | concentration of hydrogen sulfide gas is 95-100 volume% in the steady state of operation, for example.

  Further, the supply amount of the hydrogen sulfide gas is not particularly limited, but is blown so that the molar ratio is about 1.0 to 1.1 times the amount of copper contained in the slurry obtained through the reduction step S21. It is preferable. When the supply amount is less than 1.0 times in terms of the molar ratio with respect to the copper amount, the monovalent copper ions contained in the nickel chloride aqueous solution may not be sufficiently fixed as copper sulfide. On the other hand, when the supply amount is larger than 1.1 times in terms of the molar ratio with respect to the copper amount, the effect of immobilizing copper ions is not improved further, while the amount of unreacted hydrogen sulfide gas discharged increases. Therefore, it becomes inefficient from the viewpoint of economy.

  Here, as described above, hydrogen sulfide is a strong reducing agent. Generally, when hydrogen sulfide is supplied to a slurry to fix copper ions to form a copper sulfide precipitate, Fine copper sulfide having a median diameter of 1 μm or less is formed. Such fine copper sulfide is remarkably impaired in the solid-liquid separation treatment, and cannot be effectively separated and removed from the aqueous nickel chloride solution.

  However, in the present embodiment, as described above, the nickel sulfide added in the reduction step S21 is contained in the slurry, and hydrogen sulfide is supplied in the presence of the nickel sulfide. Therefore, the nickel sulfide in the slurry acts as a filter aid, and a precipitate of copper sulfide is formed using the nickel sulfide as a seed crystal, so that copper sulfide having a large particle size can be formed. . Therefore, even when copper ions are formed by immobilizing copper ions with hydrogen sulfide, copper sulfide having a large particle size can be formed while suppressing the copper sulfide from becoming finer, and thus filtration can be performed. Thus, copper ions can be effectively removed from the aqueous nickel chloride solution.

  Further, as described above, since the copper ions are fixed by hydrogen sulfide after the reduction power of nickel sulfide is maximized in the reduction step S21, the supply amount of hydrogen sulfide can be reduced. Therefore, by this, it can suppress further that the copper sulfide formed refines | miniaturizes and can further improve filterability.

  Although it does not specifically limit as temperature conditions in copper ion fixed process S22, It is preferable to set it as 60-100 degreeC. When the temperature condition is less than 60 ° C., the reaction shown in the above formulas (6) and (7) does not proceed sufficiently, and the monovalent copper ions may not be immobilized effectively. . On the other hand, when the temperature condition is higher than 100 ° C., the cost for cooling after the reaction is not preferable.

  Further, the copper ion immobilization step S22 is not particularly limited. For example, the oxidation-reduction potential is measured as needed, and the reaction is performed until the oxidation-reduction potential becomes constant. Thereby, copper ion can fully be fixed and it can prevent that copper ion remains in a cementation final solution.

(Solid-liquid separation process)
Next, in the solid-liquid separation step S23, the slurry obtained through the copper ion immobilization step S22 described above is subjected to solid-liquid separation. With this solid-liquid separation step S23, the cementation residue of copper sulfide formed in the copper ion immobilization step S22 is separated and removed, and the aqueous solution of nickel chloride is reduced to a low concentration of 0.1 g / L or less. Some cementation final solution can be obtained.

  The solid-liquid separation method in the solid-liquid separation step S23 is not particularly limited, and for example, solid-liquid separation is performed by a known method such as suction filtration using a filter paper and Nutsche, and copper sulfide as a cementation residue is separated. It can be separated and removed.

  In the present embodiment, as described above, the copper sulfide formed in the copper ion fixing step S22 is suppressed from being refined and the filterability is improved, so that solid-liquid separation can be satisfactorily performed. Thus, it is possible to effectively and efficiently obtain a nickel chloride aqueous solution that hardly contains copper as an impurity in the electrowinning.

  As described above, in the cementation step S2 in the present embodiment, first, nickel sulfide is added in the reduction step S21 to reduce divalent copper ions contained in the nickel chloride aqueous solution to monovalent copper ions, and then In the copper ion fixing step S22, hydrogen sulfide is supplied to the slurry obtained through the reduction step S21 to fix monovalent copper ions to the copper sulfide.

  Thus, by first adding nickel sulfide to reduce copper ions, the fixation reaction of copper ions with hydrogen sulfide in the copper ion fixation step S22 can be effectively and efficiently advanced. And thereby, the usage-amount of expensive hydrogen sulfide can be reduced. In addition, when forming the copper sulfide in the copper ion fixing step S22, the nickel sulfide added in the reduction step S21 can act as a seed crystal, and the copper sulfide formed by fixing the copper can be refined. It can suppress and can improve the filterability of copper sulfide. Furthermore, as described above, the amount of hydrogen sulfide used can be reduced, so that the refinement of copper sulfide formed by hydrogen sulfide can be further effectively suppressed, and the filterability is further improved. .

<Purification process>
In the liquid purification step S3, nickel chloride aqueous solution for removing impurities other than nickel from the cementation final solution (nickel chloride aqueous solution from which copper has been removed) obtained through the above-described cementation step S2 and performing electrowinning. Get.

  The liquid purification step S3 includes a deironing step, a decobalt step, a deleading step, and a dezincing step as main steps. In these steps, as a method for removing impurities from the cementation final solution, for example, an oxidation neutralization method using chlorine gas as an oxidizing agent and carbonate as an alkaline agent can be used. The oxidation neutralization method utilizes the property that when heavy metals such as cobalt and iron become high-order oxide ions, they tend to be hydroxides in the low pH range. This method is widely used for wastewater treatment.

Specifically, in this liquid purification process S3, impurities are removed by, for example, the reaction shown in the following formula (8).
2M ²⁺ + Cl ₂ + 3NiCO ₃ + 3H ₂ O →
2M (OH) ₃ + 3Ni ²⁺ + 2Cl ⁻ + 3CO ₂ (8)
(However, M is cobalt or iron.)

  As shown in the above equation (8), in the purification step S3, a chloride precipitate of impurities such as iron and cobalt of interest is formed using chlorine gas from the final cementation solution, and the impurities are removed. A nickel aqueous solution is obtained.

  In general, as the oxidizing agent used in the oxidative neutralization method, hypochlorous acid, oxygen, air and the like can be used in addition to chlorine gas. In addition to carbonates, hydroxides such as caustic soda, ammonia, etc. can be used as the alkaline agent. These chemicals are used in combination suitable for the process conditions. In the nickel refining process, it is preferable to use chlorine gas as the oxidizing agent and carbonate as the alkaline agent. The reason for using chlorine gas as the oxidant is that chlorine gas is a strong oxidant generated in the process and is easy to use. The reason why carbonate is used as the alkaline agent is that the ion concentration of nickel, sodium, sulfuric acid and the like in the entire process can be controlled and the reactivity during oxidation neutralization is excellent.

<Electrolysis process>
In the electrolysis step S4, electronickel is obtained by electrolytic extraction from the nickel chloride aqueous solution purified through the above-described liquid purification step S3.

Specifically, in the electrolysis step S4, reactions represented by the following formulas (9) and (10) occur at the cathode and the anode, respectively.
(Cathode side)
Ni ²⁺ + 2e ⁻ → Ni ⁰ (9)
(Anode side)
2Cl ⁻ → Cl ² ↑ + 2e ⁻ (10)

  That is, as shown in the above equation (9), nickel ions in the nickel chloride aqueous solution are deposited as metal (electrical nickel) on the cathode side. On the anode side, chlorine ions in the nickel chloride aqueous solution are generated as chlorine gas as shown in the above equation (10). The generated chlorine gas is used, for example, in the chlorine leaching step S1 as recovered chlorine gas.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1
Using a device in which three reaction tanks with a capacity of 60 L were connected in series, a nickel chloride aqueous solution containing 28 g / L of copper ions was supplied to the top tank at a flow rate of 36 L / Hr, and the median diameter (D50) was 35 μm. A slurry containing 300 g / L of nickel sulfide was supplied at a flow rate of 21 L / Hr to reduce the copper ions in the aqueous solution at a reaction temperature of 90 ° C. (reduction process).

  Next, the slurry after completion of the reduction step was collected, and the slurry was supplied to a reaction vessel having a capacity of 1 L at 15 mL / min. At the same time, hydrogen sulfide gas was blown into the reaction vessel, the reaction temperature was set to 60 ° C., and the reaction was performed until the oxidation-reduction potential became constant, and the copper ions in the slurry were fixed as sulfides (fixed copper ions Process). Note that the amount of hydrogen sulfide gas blown was equivalent to the amount of monovalent copper ions contained in the slurry supplied through the reduction step and the molar ratio.

  And after completion | finish of a copper ion fixed process, 1 L of obtained slurries were extract | collected, and it suction-filtered with the aspirator (made by Shibata Chemical Co., Ltd.) using Nutsche, and carried out solid-liquid separation (solid-liquid separation process).

(Example 2)
In Example 2, the copper removal treatment was performed under the same conditions as in Example 1 except that the particle size of nickel sulfide added in the reduction step was 20 μm in terms of median diameter (D50).

Example 3
In Example 3, the copper removal treatment was performed under the same conditions as in Example 1 except that the particle size of nickel sulfide added in the reduction step was 9 μm as the median diameter (D50).

(Comparative Example 1)
In Comparative Example 1, the slurry at the end of the reduction process was filtered, an aqueous solution from which the residue was removed was supplied, and copper ions were immobilized in the copper ion immobilization process under the same conditions as in Example 1. Copper treatment was performed. That is, in Comparative Example 1, the nickel sulfide added in the reduction step was removed from the slurry, and then hydrogen sulfide was supplied to fix the copper ions.

(Evaluation)
As an evaluation of the copper removal treatment in Examples 1 to 3 and Comparative Examples 1 and 2 described above, in order to confirm how much copper is removed, the final liquid copper in each step of the reduction step and the copper ion immobilization step The concentration was measured by measuring with an atomic absorption analyzer (manufactured by VARIAN). Moreover, evaluation of the filterability of the copper sulfide which is a fixed product of the formed copper ions was performed by measuring the filtration rate of suction filtration in the solid-liquid separation step.

  In the filtration, 5C filter paper having a diameter of 150 mm was used. As for the particle size of the starch, the median diameter of the residue (sulfide) formed in the copper ion immobilization step was measured with a Microtrac particle size analyzer (Honeywell).

  Table 1 shows the measurement results.

  As shown in Table 1, in Examples 1 to 3 and Comparative Example 1, the final solution copper concentration in the copper ion immobilization step is 0.001 g / L or less, and the copper ions in the nickel chloride aqueous solution are sufficiently contained. It was possible to reduce to a low concentration range.

Moreover, in Examples 1-3, the residual median diameter became 2.5 micrometers or more, refinement | miniaturization of the precipitate of the copper sulfide formed was suppressed, and the copper sulfide which has a big particle size was able to be formed. And the filtration rate of the deposit of these Examples 1-3 became 14 L / m < ² > * Hr or more, and showed favorable filterability. In particular, in Example 1 in which nickel sulfide having a median diameter of 35 μm was added and in Example 2 in which nickel sulfide having a median diameter of 20 μm was added, refinement of copper sulfide was more effectively suppressed. As a result, the filterability could be further improved.

On the other hand, in Comparative Example 1 in which the copper sulfide was immobilized by hydrogen sulfide in a state where nickel sulfide was removed by solid-liquid separation, the residual median diameter became 0.9 μm, resulting in a very fine copper sulfide precipitate. I have. Moreover, the filtration rate of the deposit was 11.3 L / m < ² > * Hr, and filterability was remarkably impaired compared with Examples 1-3.

Claims (4)

A reduction step of adding nickel sulfide to a nickel chloride aqueous solution containing copper ions and reducing the copper ions;
A copper ion immobilization step of supplying hydrogen sulfide to the slurry obtained through the reduction step and immobilizing the reduced copper ions as copper sulfide;
And a solid-liquid separation step of solid-liquid separation of the slurry obtained through the copper ion immobilization step. A method for removing copper ions in an aqueous nickel chloride solution.   2. The copper ion in an aqueous nickel chloride solution according to claim 1, wherein in the copper ion fixing step, hydrogen sulfide is supplied in a state where the nickel sulfide remains in the slurry obtained through the reduction step. Removal method.   3. The method for removing copper ions in an aqueous nickel chloride solution according to claim 1, wherein the median diameter (D50) of nickel sulfide added in the reduction step is 20 [mu] m or more. In the method for producing electric nickel, copper ions are removed from an aqueous solution of nickel chloride containing copper obtained by chlorine leaching of nickel sulfide, and electric nickel is produced by electrowinning.
A reduction step of adding nickel sulfide to the nickel chloride aqueous solution containing the copper ions and reducing the copper ions;
A copper ion immobilization step of supplying hydrogen sulfide to the slurry obtained through the reduction step and immobilizing the reduced copper ions as copper sulfide;
And a solidification process for solid-liquid separation of the slurry obtained through the copper ion immobilization process.

Images