JP2012001760A - Method for refining nickel chloride solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the loss of chlorine in a system and an amount of use of new chlorine, in a method for refining a nickel chloride solution.SOLUTION: In a process S5 for producing nickel carbonate, nickel carbonate 24 is produced from the nickel electrolysis waste liquid 20 of electrolytic nickel 18, produced from a nickel chloride solution 17 by an electrowinning method, and soda lime 22, and the filtrate 26 of the nickel carbonate 24 in an amount corresponding to the liquid amount stored in the production process system of the electrolytic nickel is returned into the system as a recovered chlorine gas 16 source in a cleaning process S3 or as a recovered chlorine gas 15 source in a chlorine leaching process S2. Thereby, the loss of chlorine in the system is reduced and the amount of use of new chlorine is reduced.

Description

  The present invention relates to a method for purifying a nickel chloride solution in an electrolytic nickel production process, and more specifically, a loss of chlorine (a loss of chlorine) in an electrolytic nickel production process system required for purifying a nickel chloride solution having a low impurity concentration. The present invention relates to a method for purifying a nickel chloride solution that reduces the amount of chlorine used and a new amount of chlorine.

  Among conventional non-ferrous metal hydrometallurgical methods, chlorine is a method for producing electric nickel from sulfides (nickel sulfides) containing metal components such as nickel, cobalt, copper, iron, etc. using electrowinning. Examples include a leaching method (see, for example, Patent Document 1 and Patent Document 2). For example, as shown in FIG. 2, the chlorine leaching method includes a cementation step S10, a chlorine leaching step S11, a liquid cleaning step S12, an electrowinning step S13, and a nickel carbonate manufacturing step S14.

  For example, leaching of nickel sulfide (sulfide) 100 in the chlorine leaching method is performed by a cementation step S10 and a chlorine leaching step S11. In the cementation step S10, for example, as shown in the following formula (1), copper ions in the chlorine leaching solution are reduced with metal nickel in the nickel sulfide 100, and the copper sulfide is converted using the sulfur in the nickel sulfide 100. A nickel leaching solution 102 from which copper is removed by immobilization as a residue 101 is obtained.

<Cementation process>
2Cu ⁺ + S ⁰ + Ni ⁰ → Cu ₂ S + Ni ⁺ (1)
Further, in the chlorine leaching step S11, for example, as shown in the following formulas (2) and (3), the metals in the residue 101 fixed in the cementation step S10 are replaced with new chlorine gas 103 or later. As described above, for example, the chlorine gas 105 collected in the electrolytic collection step S13 is leached into the liquid. Note that the sulfur in the nickel sulfide 100 is distributed to the leaching residue in the chlorine leaching step S11 and discharged out of the system.

<Chlorine leaching process>
NiS + Cl ₂ → Ni ²⁺ + S ⁰ + 2Cl ⁻ (2)
Cu ₂ S + 2Cl ₂ → 2Cu ²⁺ + S ₀ + 4Cl ⁻ (3)
In order to purify the nickel chloride solution (low impurity nickel chloride solution) 107 having a low impurity concentration used in the electrowinning step S13 from the nickel leaching solution 102 obtained in the above steps, in the liquid purification step S12, the nickel leaching solution 102 is made of nickel. Remove other impurities. Specifically, liquid purification process S12 has a deironing process, a decobalt process, a deleading process, and a dezincing process as main processes. In the iron removal step and the cobalt removal step, trace impurities are removed using an oxidation neutralization method. The oxidation neutralization method is a method using chlorine gas as an oxidizing agent and carbonate as an alkaline agent. When heavy metals such as cobalt and iron become higher-order oxide ions, hydroxides are produced in a low pH region. It uses the property that tends to become. For example, in the liquid purification step S12, as shown in the following formula (4), using the new chlorine gas 104 or the chlorine gas 106 collected in the electrowinning step S13 as described above, from the nickel leachate 102, A nickel precipitate 107 is obtained by forming a hydroxide precipitate of the impurity of interest.

<Purification process (oxidation neutralization method)>
2M ²⁺ + Cl ₂ + 3NiCO ₃ + 3H ₂ O
→ 2M (OH) ₃ + 3Ni ²⁺ + 2Cl ⁻ + 3CO ₂ (4)
(However, M is cobalt or iron.)
In the electrowinning step S13, electro nickel 108 is produced using the nickel chloride solution 107 obtained in the liquid purification step S12. For example, in the electrowinning step S13, nickel ions in the nickel chloride solution 107 are deposited as metal on the cathode side as shown in the following formula (5), and electro nickel 108 is obtained. In the electrowinning step S13, chlorine ions in the nickel chloride solution 107 are generated as chlorine gas on the anode side as shown in the following formula (6).

<Cathode reaction>
Ni ²⁺ + 2e ⁻ → Ni ⁰ (5)
<Anode reaction>
2Cl ⁻ → Cl ² ↑ + 2e ⁻ (6)
In the nickel carbonate manufacturing step S14, for example, as shown in the following formula (7), a nickel electrolytic waste liquid (nickel chloride solution) 110, which is a waste liquid in the electrowinning step S13, and soda ash (sodium carbonate) 114 are mixed, By adjusting the pH to about 7, nickel carbonate 116 used in the liquid purification step S12 is manufactured. Usually, the filtrate 118 is discharged out of the system in order to adjust the amount of liquid retained in the system. Sodium contained in the filtrate 118 is discharged out of the system after being treated in the wastewater treatment step.

<Nickel carbonate manufacturing process>
Na ₂ CO ₃ + NiCl ₂ → NiCO ₃ + 2Na ⁺ + 2Cl ⁻ (7)
By the way, the chlorine gas generated by the anode reaction in the electrowinning step S13 is a chlorine amount equimolar to the nickel amount theoretically deposited. Therefore, all the chlorine gas generated in the electrowinning step S13 is recovered and reused in the chlorine leaching step S11. In the chlorine leaching step S11, the amount of nickel equivalent to the amount of nickel deposited in the electrowinning step S13 is leached. can do. This establishes a balance between the chlorine content and the nickel content.

  However, chlorine gas is required not only in the chlorine leaching step S11 but also in the liquid purification step S12 as described above, for example. Accordingly, the chlorine gas recovered in the electrolytic collection step S13 does not actually contribute to the chlorine leaching step S11.

  Moreover, the reaction by chlorine in each process mentioned above does not advance at 100% efficiency. Chlorine is distributed in the gas phase side of the reaction tank, for example, and is contained in a large amount in the filtrate 118 that is treated as exhaust gas in a detoxification process (not shown) or discharged from the nickel carbonate production process S14. Accordingly, the chlorine content in the system tends to decrease (chlorine loss).

  As described above, in the manufacturing process of the electric nickel 108 using the chloride bath, efficient purification of the nickel chloride solution is realized by repeatedly using the chlorine retained in the system. On the other hand, there is a chlorine loss in each step in the manufacturing process of the electric nickel 108. Therefore, in order to ensure the amount of chlorine necessary for the leaching of nickel in the nickel sulfide 100, for example, in the chlorine leaching step S11 and the liquid purification step S12, new chlorine gases 103 and 104 corresponding to chlorine loss are added in the system. In addition to this, the chlorine balance must be maintained. For example, deterioration of the leaching efficiency in the chlorine leaching step S11 becomes a problem. Further, due to the increase in impurity quality in the nickel sulfide 100, the amount of chlorine required in the liquid purification step S12 increases, and an increase in the amount of new chlorine gas 104 used in connection therewith becomes a problem.

Japanese Patent Publication No.7-91599 JP 2005-248245 A

  The present invention has been proposed in view of such circumstances, and a nickel chloride solution that can reduce chlorine loss in a production process system of electronickel and can reduce the amount of new chlorine used. An object is to provide a purification method.

  The inventors of the present invention found a reduction in chlorine loss and a reduction in the amount of new chlorine used by repeating the nickel carbonate filtrate in the nickel carbonate production process in the system.

  That is, the method for purifying a nickel chloride solution according to the present invention removes impurities from a nickel leachate containing at least nickel by an oxidation neutralization method using chlorine gas and nickel carbonate in an electric nickel production process system. A method for refining a nickel chloride solution to obtain a nickel chloride solution, wherein the nickel carbonate is produced from electrolytic waste liquid of electrolytic nickel produced from the nickel chloride solution and soda ash by electrowinning, and the liquid retained in the system An amount of the nickel carbonate filtrate corresponding to the amount is returned to the system as a chlorine gas source in the system.

  The nickel chloride solution purification method according to the present invention is such that the total amount of liquid retained in the system does not exceed 60% of the total amount of liquid that can be retained in the system. Is returned to the system.

  The method for purifying a nickel chloride solution according to the present invention is characterized in that the nickel carbonate filtrate is returned to a cleaning step for obtaining the nickel chloride solution from the nickel leachate by the oxidation neutralization method.

  According to the present invention, the loss of chlorine is reduced by returning the nickel carbonate filtrate that has been dispensed to the outside of the electrolytic nickel manufacturing process system to the system according to the amount of liquid retained in the system. At the same time, the amount of new chlorine used can be reduced. Therefore, according to the present invention, it is possible to achieve the purification of a nickel chloride solution with high chlorine recovery efficiency.

It is process drawing which shows an example of the purification method of the nickel chloride solution which concerns on this invention. It is process drawing which shows an example of the refinement | purification method of the conventional nickel chloride solution.

Hereinafter, an example of a specific embodiment to which the present invention is applied (hereinafter referred to as “the present embodiment”) will be described in the following order with reference to the drawings.
1. 1. Nickel wet refining method 1-1. Processing of each process 1-2. Repetitive amount of filtrate 1-3. 1. Sodium concentration Other Embodiment 3 Example

<1. Purification method of nickel chloride solution>
(1-1. Process of each process)
For example, as shown in FIG. 1, the nickel chloride purification method according to the present embodiment includes a cementation step S1, a chlorine leaching step S2, a liquid purification step S3, an electrowinning step S4, and a nickel carbonate manufacturing step. S5.

  In the cementation step S1, for example, the copper in the copper-containing nickel chloride solution is subjected to a substitution reaction with the nickel in the nickel sulfide 10 to remove the copper, and the nickel leaching solution (removed copper chloride solution) 12 is included. Residue 11 is obtained. That is, in the cementation step S1, nickel sulfide 10 is subjected to a cementation reaction with copper ions. As the nickel sulfide 10, for example, a nickel mat containing nickel sulfide as a main component and containing cobalt, copper or the like as impurities is used. That is, in the cementation step S1, for example, as shown in the equation (8), copper ions in a chlorine leaching solution (copper-containing nickel chloride solution) containing copper are reduced with metal nickel in the nickel sulfide 10 to obtain nickel sulfide. The sulfur in the product 10 is used to immobilize as a residue 11 containing copper sulfide to obtain a nickel leachate 12 from which copper has been removed.

2Cu ⁺ + S ⁰ + Ni ⁰ → Cu ₂ S + Ni ⁺ (8)
In the chlorine leaching step S2, for example, the residue 11 and the nickel sulfide 10 obtained in the cementation step S1 are converted into a new chlorine gas 13 (hereinafter referred to as “new chlorine gas 13”), for example, as described in detail later. The copper gas-containing nickel chloride solution described above is obtained by leaching with the chlorine gas 15 recovered in the electrowinning step S4 (hereinafter referred to as “recovered chlorine gas 15”). That is, in the chlorine leaching step S2, the residue 11 separated into the nickel leaching solution 12 and the residue 11 in the cementation step S1 is leached with chlorine. Specifically, in the chlorine leaching step S2, for example, as shown in the equations (9) and (10), the metals in the residue 11 fixed in the cementation step S1 are replaced with new chlorine gas 13 or recovered chlorine gas. 15 for leaching into the liquid. Although not shown, a part of the copper-containing nickel chloride solution obtained in the chlorine leaching step S2 is used as an electrolytic feed solution. Copper powder is obtained by electrowinning using this electrolytic feed solution, an insoluble electrode as the anode, and a titanium electrode as the cathode, and the electrolytic waste solution is supplied to the cementation step S1.

NiS + Cl ₂ → Ni ²⁺ + S ⁰ + 2Cl ⁻ (9)
Cu ₂ S + 2Cl ₂ → 2Cu ²⁺ + S ₀ + 4Cl ⁻ (10)

  In the liquid purification step S3, the nickel leachate 12 is subjected to a new chlorine gas 14 (hereinafter referred to as “new chlorine gas 14”) as an oxidant, or a chlorine gas 16 (hereinafter referred to as “electrolytic collection step S4” described above). The "recovered chlorine gas 16") and nickel carbonate 24 as an alkaline agent are added to carry out an oxidation neutralization reaction. Thereby, in liquid purification process S3, the nickel chloride solution 17 from which impurities other than nickel were removed from the nickel leaching solution 12 is obtained. Thus, in the liquid purification step S3, the nickel chloride solution having a low impurity concentration used in the electrowinning step S4 is purified. For example, liquid purification process S3 has a deironing process, a decobalt process, a deleading process, and a dezincing process as main processes. In the iron removal process and the cobalt removal process, trace amounts of impurities are removed using an oxidation neutralization method.

  The reason why chlorine gas is used as an oxidant for chemicals used in the oxidative neutralization method is that chlorine gas is a strong oxidant generated in the process and is easy to use. In addition, nickel carbonate is used as an alkaline agent because nickel carbonate produced by reacting the waste liquid from the electrolytic collection step S4 with sodium carbonate is produced, for example, than nickel hydroxide produced by reacting with sodium hydroxide. This is because the filterability of the product is good, and the reactivity during oxidation neutralization is good.

  In the liquid purification step S3, for example, new chlorine gas 14 or recovered chlorine gas 16 is used for oxidation, nickel carbonate 24 is used for neutralization, pH is set to 3.8 to 4.8, and ORP (Oxidation-reduction Potential). Is controlled at 1000 to 1100 mV (Ag / AgCl electrode). Thereby, in liquid purification process S3, as shown to (11) Formula, the hydroxide precipitation of the target impurity is formed, for example.

2M ²⁺ + Cl ₂ + 3NiCO ₃ + 3H ₂ O
→ 2M (OH) ₃ + 3Ni ²⁺ + 2Cl ⁻ + 3CO ₂ (11)
(However, M is cobalt or iron.)

  In the electrolytic collection process S4, the nickel electrolysis 18 is manufactured by the electrolytic collection method using the nickel chloride solution 17 purified in the liquid purification process S3. In the electrowinning step S4, nickel ions in the nickel chloride solution 17 are deposited as metal (electrical nickel 18) on the cathode side, for example, as shown in equation (12). In the electrowinning step S4, chlorine ions in the nickel chloride solution 17 are generated as chlorine gas on the anode side, for example, as shown in equation (13). This chlorine gas is used as, for example, the recovered chlorine gas 15 and the recovered chlorine gas 16 described above.

Ni ²⁺ + 2e ⁻ → Ni ⁰ (12)
2Cl ⁻ → Cl ² ↑ + 2e ⁻ (13)

In the nickel carbonate manufacturing step S5, as shown in the equation (14), a nickel chloride solution (hereinafter referred to as “nickel electrolytic waste solution”) 20 which is a waste solution of the electrowinning step S4 and soda ash (sodium carbonate) 22 are mixed. And nickel carbonate 24 is manufactured by adjusting pH to about 7-8. This nickel carbonate 24 is used in the above-described liquid purification step S3. In the nickel carbonate manufacturing step S5, for example, a continuous solid-liquid separator is used. In the filtrate (drainage) 26 after the nickel carbonate 24 is produced in the nickel carbonate production step S5, for example, as shown in the equation (14), sodium ions (Na ⁺ ) and chloride ions (Cl ⁻ ) And are distributed.

Na ₂ CO ₃ + NiCl ₂ → NiCO ₃ + 2Na ⁺ + 2Cl ⁻ (14)
In the nickel chloride purification method according to the present embodiment, in the nickel carbonate production step S5, the nickel carbonate 24 is obtained from the nickel electrolytic waste liquid 20 of the electric nickel 18 and the soda ash 22 produced from the nickel chloride solution 17 by the electrolytic collection method. The amount of the filtrate 26 of nickel carbonate 24 corresponding to the amount of liquid stored in the manufacturing process system of the electric nickel 18 (hereinafter simply referred to as “in the system”) is the chlorine gas source in the liquid purification step S3, or It returns to the system as a chlorine gas source in the chlorine leaching step S2. That is, in the method for purifying nickel chloride according to the present embodiment, in addition to the above-described new chlorine gas 13, new chlorine gas 14, recovered chlorine gas 15 and recovered chlorine gas 16, conventionally, the production of nickel carbonate is used as a chlorine gas source. The filtrate 26 that has been dispensed out of the system in step S5 is repeatedly used according to the amount of liquid retained in the system.

  This reduces chlorine loss in the system and, for example, reduces the amount of new chlorine gas 13 used in the chlorine leaching step S2 and the new chlorine gas 14 used in the liquid purification step S3, resulting in high chlorine recovery efficiency. Purification of the nickel solution can be realized. Further, by reducing the chlorine loss in the system, it is possible to reduce the trouble of treating the filtrate 26 with wastewater and the processing cost associated with the wastewater treatment of the filtrate 26. Furthermore, by returning the filtrate 26 to the system according to the amount of liquid retained in the system, chlorine loss in the system can be reduced while controlling the liquid volume balance in the system.

  Here, when the filtrate 26 is returned from the nickel carbonate production step S5 to the electrowinning step S4, the composition of the nickel chloride solution 17 used in the electrowinning changes, and the nickel chloride solution 17 is re-prepared. It takes time and processing efficiency decreases. Therefore, in the nickel chloride purification method according to the present embodiment, it is preferable to return the filtrate 26 of the nickel carbonate 24 to a process other than the electrowinning process S4, for example, the liquid purification process S3.

(1-2. Repetitive amount of filtrate)
In the nickel carbonate manufacturing step S5, when the amount of liquid retained in the system is within a predetermined amount, the amount of the filtrate 26 corresponding to the amount of liquid retained in the system is returned to the liquid purification step S3 as a chlorine gas source. On the other hand, in the nickel carbonate manufacturing step S5, when the amount of liquid retained in the system exceeds a predetermined amount, the filtrate 26 is discharged out of the system. Thereby, while preventing the liquid held in the system from overflowing, chlorine loss can be reduced and the amount of new chlorine used can be reduced.

  For example, in the nickel carbonate production step S5, it is preferable to return the filtrate 26 to the system so that the total amount of liquid retained in the system does not exceed 60% of the total amount of liquid that can be retained in the system. . If the amount of the filtrate 26 returned from the nickel carbonate production S6 to the liquid purification step S3 is too small, the amount of chlorine recovered decreases, and the amount of new chlorine gas used cannot be reduced, so that the processing becomes inefficient. . Moreover, when there is too much quantity of the filtrate 26 which returns to the liquid purification process S3 from nickel carbonate manufacturing process S5, the water balance of the liquid held in a system will worsen, and the liquid quantity held in a system will increase rapidly. Will tend to. Here, the case where the amount of liquid in the system suddenly increases means, for example, the case where the total amount of liquid held in the system increases by 10% or more per day. Moreover, when there is too much quantity of the filtrate 26 returned to liquid purification process S3, the sodium concentration in the liquid held in a system will rise too much, and the quality of the electric nickel 18 obtained by electrowinning process S4 will be affected. There is a risk of getting out.

More specifically, for example, when the total amount of liquid that can be retained in the system is 1000 m ³ , the carbonic acid production process S5 is performed so that the total amount of liquid retained in the system does not exceed 600 m ^3. The filtrate 26 of nickel 24 is returned to the liquid purification step S3. In this case, in the nickel carbonate manufacturing step S5, when the filtrate 26 is returned to the cleaning step S3 at a rate of about 5 to 20 L / min, and the total amount of liquid retained in the system is 600 m ³ or more. The amount of the filtrate 26 returned to the liquid purification step S3 is temporarily reduced, or all the filtrate 26 is discharged out of the system from the nickel carbonate production step S5. As described above, in the method for purifying nickel chloride according to the present embodiment, the flow rate of the filtrate 26 that is repeatedly returned from the nickel carbonate production step S5 to the liquid purification step S3 is adjusted while observing fluctuations in the amount of liquid retained in the system. It is preferable to do. Thereby, for example, even if the liquid held in the system tends to decrease due to evaporation, an inexpensive and inexpensive nickel chloride solution can be purified.
(1-3. Sodium concentration)
As described above, in the method for purifying nickel chloride according to the present embodiment, the filtrate 26 is returned from the nickel carbonate manufacturing step S5 to the cleaning step S3 and reused. However, if the filtrate 26 is repeatedly reused in the system, the sodium ion concentration in the liquid held in the system increases, the hardness of the electrical nickel 18 increases, and the quality of the electrical nickel 18 may not be kept constant. There is. Therefore, in actual operation, for example, it is desirable to manage the sodium concentration by measuring the sodium concentration in the nickel chloride solution collected in the electrolytic collection step S4. For example, when the sodium concentration in the liquid retained in the system becomes too high, the amount of the filtrate 26 returned from the nickel carbonate production process S5 to the liquid purification process S3 is adjusted, It is preferable to reduce the sodium ion concentration. Thereby, the quality of the electric nickel 18 manufactured in the electrowinning step S4 can be kept constant.

  As described above, in the method for purifying a nickel chloride solution according to the present embodiment, the filtrate 26 of nickel carbonate 24 that has conventionally been dispensed out of the system in the nickel carbonate manufacturing step S5 is retained in the system. Return according to the liquid volume. This reduces chlorine loss in the system, reduces the amount of new chlorine used, for example, reduces the amount of new chlorine gas 14 used in the liquid purification step S3, and reduces the amount of new chlorine used in the chlorine leaching step S2. The amount of chlorine gas 13 used can be reduced. Thus, in the purification method of the nickel chloride solution according to the present embodiment, the purification of the nickel chloride solution 17 with high chlorine recovery efficiency can be realized. Further, in the method for purifying the nickel chloride solution according to the present embodiment, it is possible to return the filtrate 26 of the nickel carbonate 24 in accordance with the amount of liquid retained in the system, so that it is possible to treat the filtrate 26 with wastewater, or the filtrate. The processing cost accompanying the 26 wastewater treatment can be reduced.

<2. Other embodiments>
In the above description, the filtrate 26 is described as being returned from the nickel carbonate production step S5 to the liquid purification step S3. However, the present invention is not limited to this example. For example, the filtrate 26 may be returned to a process other than the electrolytic collection process S4, for example, the cementation process S1 or the chlorine leaching process S2 in consideration of the piping configuration in the system.

  In the above description, the filtrate 26 is changed from the nickel carbonate production process S5 to the liquid purification process S3 so that the total liquid volume in the system does not exceed 60% of the total liquid volume that can be held in the system. It was explained as returning. However, the amount of the filtrate 26 returned from the nickel carbonate manufacturing step S5 to the system may be changed according to the equipment scale and the processing capacity of the equipment.

Furthermore, in the nickel chloride solution purification method described above, the processing equipment for executing each step includes a detection unit that detects the amount of liquid in a tank that stores the liquid in each step, and a detection result in the detection unit. A control unit that monitors the total amount of liquid retained in the system and controls the supply amount of the filtrate 26 may be provided. By using such processing equipment, the supply amount of the filtrate 26 can be automatically controlled.
<3. Example>

  Hereinafter, specific examples of the present invention will be described. The scope of the present invention is not limited to any of the following examples.

(About test contents)
A method for repeating nickel carbonate in the nickel carbonate production process will be described. With respect to the solid-liquid separated nickel carbonate, a dehydrated nickel carbonate cake is discharged on the solid side. The nickel carbonate cake is slurried with a nickel chloride solution in a repulp tank and then used in a liquid purification step (impurity removal step). The solid-liquid separated nickel carbonate filtrate is once stored in the filtrate tank and sent to the wastewater treatment process through the liquid feed pipe, but is branched into the repulp tank by branching from the liquid feed pipe. Incorporated into the system.

(Example)
In Example 1, the amount of nickel carbonate filtrate returned from the nickel carbonate production process to the liquid purification process (hereinafter referred to as “filtrate repeat amount”) was 5 L / min. In Example 2, the filtrate repeat amount was 10 L / min. In Example 3, the filtrate repeat amount was 20 L / min. The filtrate repeat amount in Examples 1 to 3 is set so that the total liquid amount retained in the system does not exceed 60% with respect to the total liquid amount (1000 m ³ ) that can be retained in the system. did.

(Comparative example (conventional operation))
In the comparative example, the filtrate repeat amount was set to 0 L / min. That is, in the comparative example, all the liquids were sent to the wastewater treatment process without returning the filtrate from the nickel carbonate production process to the liquid purification process.

  Table 1 shows the results of Examples 1 to 3 and the comparative example.

  In Table 1, “nickel carbonate filtrate repeat amount” refers to the filtrate repeat amount described above, that is, the amount of nickel carbonate filtrate returned from the nickel carbonate production process to the liquid purification process. Further, the “new chlorine use amount” indicates the amount of chlorine gas newly introduced into the system for use in, for example, a chlorine leaching process or a liquid purification process. The “chlorine recovery amount” indicates the amount of chlorine contained in the filtrate recovered in the nickel carbonate production process. The total of the new chlorine usage and the chlorine recovery is the total usage of chlorine used in the system. The “in-system sodium concentration” indicates, for example, the sodium concentration in the nickel chloride solution 17 used in the electrowinning process.

(Evaluation of chlorine recovery)
In the comparative example, since the filtrate repetition amount of nickel carbonate was 0 L / min, the chlorine recovery amount was 0 t / month.

  In Example 1, the chlorine recovery amount was 5.6 t / month by setting the filtrate repetition amount of nickel carbonate to 5 L / min. Therefore, in Example 1, the chlorine loss could be reduced by about 1.7% compared to the comparative example. Moreover, in Example 1, the new chlorine usage was able to be reduced about 8 t / month compared with the comparative example.

  In Example 2, the chlorine recovery amount was 11.5 t / month by setting the filtrate repetition amount of nickel carbonate to 10 L / min. Therefore, in Example 2, the chlorine loss could be reduced by about 3.6% compared to the comparative example. Moreover, in Example 2, the amount of new chlorine used could be reduced by about 12 t / month compared with the comparative example.

  In Example 3, the chlorine recovery amount was 23.5 t / month by setting the filtrate repetition amount of nickel carbonate to 20 L / min. Therefore, in Example 3, the chlorine loss could be reduced by about 7.3% as compared with the comparative example. Moreover, in Example 3, the amount of new chlorine used could be reduced by about 24 t / month compared with the comparative example.

  Thus, in Examples 1 to 3, with the increase in the amount of nickel carbonate filtrate repeated, the amount of chlorine recovered increases compared to the comparative example, and the amount of chlorine loss is reduced, thereby reducing the amount of chlorine loss. Was able to reduce the amount of new chlorine used.

(Evaluation of sodium concentration in the system)
In the comparative example, the sodium concentration in the system was 12.5 g / L. On the other hand, in Example 1, the sodium concentration in the system was 12.8 g / L. In Example 2, the in-system sodium concentration was 13.6 g / L. In Example 3, the in-system sodium concentration was 15.8 g / L. As described above, in Examples 1 to 3, although the sodium concentration in the system was slightly increased as compared with the comparative example, the concentration was 16 g / L, which was not a problem with the quality of the electric nickel obtained in the electrowinning process. Stayed around.

(Evaluation of the amount of liquid in the system)
In Examples 1 to 3, there was no particular problem with respect to the amount of liquid retained in the system because the amount of liquid in the system did not rapidly increase with repeated nickel carbonate filtrate.

  In addition, when a test in which the repetitive amount of the nickel carbonate filtrate was increased stepwise to 30 L / min, 40 L / min, and 50 L / min was carried out, the amount of liquid in the system rapidly increased within a few days after the start of the test. Because of the increasing tendency, it was forced to reduce the filtrate repeat amount. From this result, it was found that the reduction of chlorine loss due to repeated nickel carbonate filtrate and the reduction of the amount of new chlorine used are limited by the total amount of liquid held in the system.

  From the above results, in Examples 1 to 3, the nickel carbonate filtrate was added so that the total amount of liquid retained in the system did not exceed 60% of the total amount of liquid retained in the system. Since it was returned to the system, chlorine loss was reduced and the amount of new chlorine used could be reduced. Moreover, in Example 1- Example 3, there was no problem in particular about the increase in the amount of liquid held in the system accompanying the repetition amount of the nickel carbonate filtrate. Therefore, in Examples 1 to 3, the amount of new chlorine gas used is reduced by reducing the chlorine loss while adjusting the liquid amount balance in the system so that the liquid held in the system does not overflow. I found out that I can do it.

  10,100 Nickel sulfide, 11,101 Residue, 12,102 Nickel leachate, 13, 14, 15, 16, 103, 104, 105, 106 Chlorine gas, 17,107 Nickel chloride solution, 18,108 Electro nickel, 20 , 110 Nickel electrolytic waste liquid, 22,114 Soda ash, 24,116 Nickel carbonate, 26,118 Filtrate

Claims (3)

A method for refining a nickel chloride solution in which a nickel chloride solution is obtained by removing impurities from a nickel leachate containing at least nickel by an oxidation neutralization method using chlorine gas and nickel carbonate in an electric nickel production process system. ,
The nickel carbonate is produced from electrolytic nickel electrolytic waste solution and soda ash produced from the nickel chloride solution by electrowinning, and the nickel carbonate filtrate in an amount corresponding to the amount of liquid retained in the system, A method for purifying a nickel chloride solution, characterized by being returned to the system as a chlorine gas source in the system.   The nickel carbonate filtrate is returned to the system so that the total amount of liquid retained in the system does not exceed 60% of the total amount of liquid that can be retained in the system. Item 2. A method for purifying a nickel chloride solution according to Item 1.   The method for purifying a nickel chloride solution according to claim 1 or 2, wherein the filtrate of the nickel carbonate is returned to a cleaning step for obtaining the nickel chloride solution from the nickel leachate by the oxidation neutralization method.

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