JP6375937B2 - Leaching control system and leaching control method - Google Patents

Description

  The present invention relates to a leaching control system and a leaching control method. More specifically, the present invention relates to a raw material nickel mixed sulfide subjected to chlorine leaching treatment with chlorine gas, and an electrowinning method from a resulting chlorine leaching solution (nickel chloride solution). The present invention relates to a leaching control system and a leaching control method in a chlorine leaching process in an electric nickel manufacturing process for manufacturing electric nickel.

  Conventionally, as a method for producing electric nickel, an electric nickel production process has been adopted by a chlorine leaching method. Specifically, nickel mixed sulfide (MS) is a mixture of nickel (Ni), cobalt (Co), etc. produced by sulfuric acid leaching from nickel matte and low grade laterite ore produced from dry smelting. )) As a raw material, chlorine leaching (chlorine leaching process (CP process)) of most metals such as nickel, cobalt, copper (Cu) contained in the raw material, and a solution obtained by leaching chlorine (nickel chloride) After removing metal impurities and the like from the solution, electrolytic nickel is produced by electrowinning in the electrolysis process (for example, Patent Documents 1 and 2). In the electrolysis process, chlorine gas is generated from the anode side, and the chlorine gas is transferred to the chlorine leaching process and used for metal chlorine leaching treatment.

  The nickel mixed sulfide used as a raw material contains a particularly large amount of nickel and copper, and a chlorine leaching reaction occurs due to the treatment in the chlorine leaching process described above, and a high-concentration chloride solution mainly composed of Ni and Cu is produced. Can be obtained.

  On the other hand, in the chlorine leaching process, in addition to the nickel mixed sulfide slurry (MS slurry), the residue (cementum) from the cementation process (CM process) for fixing copper in the nickel chloride solution obtained by chlorine leaching. The slurry of Cation residue (CMR)) is added at the same time, and chlorine leaching treatment is performed on two types of raw materials, MS slurry and CMR slurry. Since the cementation residue contains a large amount of immobilized Cu, when it dissolves in the liquid, it becomes Cu ions, and acts as a carrier that absorbs chlorine and oxidizes the metal during chlorine leaching. From this, the nickel leaching and the cementation residue are added together and allowed to react, whereby metal leaching such as nickel can be efficiently advanced.

  The high-concentration solution generated by the reaction in the chlorine leaching step, that is, the nickel chloride solution, is sent to the cementation step again through a filtration process for separating the leaching residue. As shown in FIG. 2, the chlorine leaching process and the cementation process are circulated in the system. A liquid (nickel chloride solution) generated in the chlorine leaching process and separated into solid and liquid is referred to as “CPL”.

JP 2009-46736 A Japanese Patent No. 4924754

  In the chlorine leaching process described above, it is important to constantly monitor the state of the leaching reaction of a metal such as Ni and maintain a constant leaching rate. An important medium for maintaining and managing this leaching rate is the oxidation-reduction potential (ORP) during the chlorine leaching reaction. In order to effectively leach metal, it is important to maintain the ORP in a certain area as its environment. Actually, the ORP in the tank (chlorine leaching reaction tank (CP tank)) is constantly monitored. By maintaining the ORP within a certain range, a stable leaching rate can be ensured.

  In the chlorine leaching reaction in the chlorine leaching process, the optimum value of ORP is determined by the relationship with the Cu ion concentration. Therefore, maintaining the ORP within a certain range means that the Cu ion concentration in the reaction solution is stable. However, conversely, if the Cu concentration in the reaction solution fluctuates, the ORP shows a value that deviates from the optimum region, and this indicates that the leaching rate is reduced.

  Here, FIG. 9 shows a system configuration diagram of a chlorine leaching process in a conventional chlorine leaching process. As shown in the block diagram of FIG. 9, conventionally, the chlorine gas blowing flow rate supplied to the chlorine leaching reaction tank (No. 0A-CP tank) and the addition amount of nickel mixed sulfide (MS) as a raw material are respectively It is controlled independently. Usually, when the ORP of the solution in the CP tank fluctuates as the Cu ion concentration fluctuates, the ORP is adjusted to the optimum value by adjusting the amount of cementation residue (CMR) added during the chlorine leaching reaction. It has been corrected. However, since the cementation residue itself added for adjustment naturally contains fixed Cu, even if the ORP is temporarily restored to the optimum region, this solution is circulated in the system thereafter. For this reason (see FIG. 8), the Cu ion concentration in the entire system eventually changes due to the circulation.

  When the Cu concentration is lowered, as described above, the metal leaching reaction efficiency is lowered, and in this case, the amount of nickel mixed sulfide added as a raw material must be reduced in order to adjust the Cu concentration in the system. . However, reducing the addition amount of the raw material nickel mixed sulfide naturally reduces the processing amount, and the production efficiency of electro nickel is significantly reduced.

  The present invention has been made in view of such a situation, and in the chlorine leaching process in the chlorine leaching process, the fluctuation of the ORP can be suppressed and stably maintained in the optimum region range. It aims at providing the method which can stabilize a leaching rate.

  The inventors of the present invention have made extensive studies in order to solve the above-described problems. As a result, based on the amount of chlorine gas blown into the reaction tank, the amount of MS to be processed in the entire chlorine leaching step S1 and the amount of MS to be processed in the reaction tank are determined, and the ORP accompanying the leaching reaction caused thereby. It was found that the ORP at the time of chlorine leaching reaction can be stably maintained within the optimum region range by determining and adding the amount of CMR added in accordance with the variation, and the present invention has been completed. That is, the present invention provides the following.

  (1) A first invention of the present invention is a chlorine leaching process in which a chlorine leaching treatment is performed on a nickel mixed sulfide with chlorine gas in a reaction vessel to obtain a chlorine leaching solution in which a metal component is leached, and the chlorine leaching. A cementation step of immobilizing copper contained in the chlorine leachate obtained by the treatment to obtain a cementation final solution and a cementation residue, and after performing a liquid purification treatment on the cementation final solution, electrolysis An electrolysis step for producing electric nickel and chlorine gas by treatment, and a leaching control system in the chlorine leaching step in the manufacturing process of electric nickel, wherein the chlorine gas supply unit supplies the chlorine gas into the reaction vessel A raw material supply unit for supplying the nickel mixed sulfide as a raw material into the reaction layer, and a cementation residue obtained in the cementation step. A cementation residue addition unit for adding the inside of the reaction vessel, the chlorine gas supply unit calculates the amount of chlorine gas blown into the reaction vessel in the chlorine leaching step, the raw material supply unit, Based on the chlorine gas blowing amount calculated in the chlorine gas supply unit, the amount of nickel mixed sulfide to be subjected to chlorine leaching treatment is determined, and the amount of nickel mixed sulfide is supplied into the reaction vessel, In the cementation residue addition unit, the amount of cementation residue added to the reaction vessel is determined based on the measurement result of the oxidation-reduction potential in the reaction vessel, and the amount of cementation residue in the reaction vessel is determined. It is a leaching control system characterized by adding.

  (2) According to a second aspect of the present invention, in the first aspect described above, a plurality of the reaction vessels are provided, and the chlorine gas supply unit blows each chlorine gas into the plurality of reaction vessels. The total flow rate of chlorine gas is calculated by adding together, and in the raw material supply unit, based on the total flow rate of chlorine gas calculated in the chlorine gas supply unit, nickel mixing is performed to perform chlorine leaching treatment in one reaction tank The leaching control system is characterized in that a treatment amount of sulfide is determined, and a nickel mixed sulfide of the treatment amount is supplied into the reaction vessel.

  (3) According to a third aspect of the present invention, in the first or second aspect described above, the cementation residue addition unit includes the measurement result of the oxidation-reduction potential in the reaction tank and the raw material supply unit. Leaching characterized in that the amount of cementation residue added to the reaction vessel is determined based on the determined nickel mixed sulfide throughput, and the addition amount of cementation residue is added into the reaction vessel. Control system.

  (4) A fourth invention of the present invention is a chlorine leaching process for obtaining a chlorine leaching solution obtained by leaching a nickel mixed sulfide with a chlorine gas in a reaction tank with a chlorine gas and leaching a metal component, and the chlorine leaching. A cementation step of immobilizing copper contained in the chlorine leachate obtained by the treatment to obtain a cementation final solution and a cementation residue, and after performing a liquid purification treatment on the cementation final solution, electrolysis An electrolysis step for producing electric nickel and chlorine gas by treatment, and a leaching control method in the chlorine leaching step in the manufacturing process of electric nickel, wherein the amount of chlorine gas blown into the reaction tank in the chlorine leaching step is A first step to calculate, a second step to determine the amount of nickel mixed sulfide to be leached based on the calculated chlorine gas blowing amount, Based on the treated amount of the nickel mixed sulfide, the third step of supplying the treated amount of nickel mixed sulfide to the reaction vessel, and the fourth step of measuring the oxidation-reduction potential in the reaction vessel were measured. And a fifth step of determining an addition amount of the cementation residue obtained in the cementation step based on the oxidation-reduction potential and adding the addition amount of cementation residue to the reaction vessel. This is a leaching control method.

  According to the present invention, in the chlorine leaching process in the chlorine leaching process, fluctuations in the ORP can be suppressed and stably maintained in the optimum region range. Thereby, the nickel leaching rate from raw materials, such as nickel mixed sulfide, can be stabilized.

It is process drawing of an electrical nickel manufacturing process. No. 0A tank, no. 0B tank, No. It is a block diagram when the case where a chlorine leaching process is performed in the reaction tank of a total of 5 tanks of 1-3 tanks is made into an example. It is a block diagram of the leaching control system in the chlorine leaching process according to the first embodiment. It is a block diagram of the leaching control system in the chlorine leaching process according to the second embodiment. It is a flowchart which shows the flow of the leaching control method which concerns on 1st Embodiment. It is a graph which shows an ORP measurement result when performing a chlorine leaching process in a chlorine leaching process, and (A) is an ORP measurement result when performing a leaching process based on the leaching control system configuration according to the first embodiment. (B) shows the ORP measurement result when the leaching process is performed based on the conventional system configuration. It is a flowchart which shows the flow of the leaching control method which concerns on 2nd Embodiment. It is a conceptual diagram for demonstrating circulating in the system of the nickel chloride solution between a chlorine leaching process and a cementation process. It is a system block diagram of the leaching process in the conventional chlorine leaching process.

Hereinafter, specific embodiments of the present invention (hereinafter referred to as “present embodiments”) will be described in detail in the following order with reference to the drawings. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention.
1. Electro nickel manufacturing process 2. Leaching control system in chlorine leaching process 2-1. First embodiment 2-2. Second embodiment 3. 3. Leaching control method in chlorine leaching process 3-1. First embodiment 3-2. Second embodiment

<< 1. Electrical nickel manufacturing process >>
In the leaching control system and the leaching control method according to the present embodiment, the nickel mixed sulfide as a raw material is subjected to chlorine leaching treatment with chlorine gas, and the resulting nickel leaching solution (nickel chloride solution) is electronicked by electrowinning. The leaching control system and the leaching control method in the chlorine leaching process in the electrolytic nickel manufacturing process for manufacturing the steel.

  First, prior to the description of the leaching control system and the leaching control method in this chlorine leaching process, an electric nickel manufacturing process having a chlorine leaching process will be described.

  FIG. 1 is a process diagram of an electrolytic nickel manufacturing process. As shown in this process diagram, the manufacturing process of electric nickel includes a chlorine leaching step S1 in which a chlorine leaching process is performed on a nickel mixed sulfide with chlorine gas in a reaction tank, and copper contained in the obtained chlorine leaching solution. A cementation step S2 to be immobilized, a liquid purification step S3 for subjecting the obtained cementation final solution to a liquid purification treatment, and an electrolysis step S4 for obtaining electric nickel by electrolytic treatment from the solution after the liquid purification. Hereinafter, each step will be specifically described.

[Chlorine leaching process]
In the chlorine leaching step S1, for example, nickel mixed sulfide (MS) obtained by wet smelting treatment of nickel oxide ore is used as a raw material, and metal components such as nickel and copper are oxidatively leached with chlorine gas, and a chlorine leaching solution (copper-containing liquid) A nickel chloride solution).

  In the chlorine leaching in the chlorine leaching step S1, the chlorine gas recovered in the electrolysis step S4 described later is supplied to the chlorine leaching reaction tank, and the leaching treatment of metal components such as nickel in the nickel mixed sulfide is performed by the chlorine gas. Then, a nickel chloride solution (copper-containing nickel chloride solution) is produced as a chlorine leaching solution. In addition, the nickel mixed sulfide used as a raw material can be repulped and slurried with a nickel chloride solution obtained in the electrolysis step S4, for example.

For example, in the chlorine leaching step S1, 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 (3)

  As shown in this reaction formula, in the chlorine leaching step S1, when a nickel mixed sulfide slurry as a raw material is sent to a chlorine leaching reaction tank, nickel sulfide, copper sulfide, etc. contained in the nickel mixed sulfide These metal components are oxidized and leached by divalent copper ions oxidized by chlorine gas to produce a nickel chloride solution as a chlorine leaching solution. In the chlorine leaching step S1, the cementation residue (CMR) generated in the cementation step S2, which will be described later, is also transferred to the chlorine leaching reaction tank and processed together with the nickel mixed sulfide. The cementation residue contains fixed copper sulfide, unreacted nickel, and the like.

  By the chlorine leaching process using chlorine gas as described above, the generated chlorine leaching solution is sent to a cementation step S2 described later, and copper in the solution is fixed and removed. On the other hand, in the chlorine leaching step S1, a chlorine leaching residue mainly containing sulfur remains as a solid phase. The sulfur in the chlorine leaching residue is recovered as a product.

  Here, the chlorine leaching reaction in the chlorine leaching step S1 is not particularly limited, but can be performed using a plurality of reaction tanks (chlorine leaching reaction tank (CP tank)). FIG. 0A tank, no. 0B tank, No. 1-No. It is a block diagram when the case where a chlorine leaching process is performed using 3 tanks and a total of 5 reaction tanks is taken as an example. In addition, CP tank is not restricted to what consists of such 5 tanks, Even if it is 1 tank, it may consist of other several tanks.

  More specifically, as shown in FIG. 0A tank, no. 0B tank, No. 1-No. In the case of performing 3 tanks in a total of 5 tanks, first, the raw material nickel mixed sulfide (MS) is No. 0A tank and No. It is supplied to the 0B tank. No. 0A tank and No. It is configured in parallel with the 0B tank. The treatment solution is sent to one tank due to overflow. From No. 1 tank To 2 tanks, No. No. 2 The three tanks are sequentially sent by overflow. Chlorine gas necessary for the leaching reaction is blown into all of these five reaction tanks, and a metal such as Ni is leached in each reaction tank.

[Cementation process]
In the cementation step S2, the nickel chloride solution (copper-containing nickel chloride solution) that is the chlorine leaching solution generated in the chlorine leaching step S1 is fed, and the copper in the nickel chloride solution is fixed and removed. Specifically, in the cementation step S2, the nickel chloride solution is made of, for example, a nickel mat produced from dry smelting, and pulverized and repulped by the nickel chloride solution generated in the subsequent electrolysis step S4. Add the prepared slurry. Further, in the cementation step S2, a chlorine leaching residue mainly containing sulfur generated as a by-product in the chlorine leaching step S1 is added.

For example, in the cementation step S2, reactions shown in the following formulas (4) to (7) occur.
Ni + Cu2 ⁺ → Ni2 ⁺⁺ Cu ⁺ (4)
Ni ₃ S ₂ + 2Cu ²⁺ → Ni ²⁺ + 2NiS + 2Cu ⁺ (5)
Ni + 2Cu ⁺ + S → Ni ²⁺ + Cu ₂ S (6)
_{^{Ni 3 S 2 + + 2Cu +}} + S → Ni 2+ + 2NiS + Cu 2 S ··· (7)

  As shown in this reaction formula, in the cementation step S2, divalent copper ions in the nickel chloride solution are reduced to monovalent copper ions by the reducing power of nickel metal and nickel sulfite in the nickel mat, and the monovalent copper ions are reduced. Copper in the nickel chloride solution is removed by fixing copper ions as copper sulfide with sulfur in the chlorine leaching residue.

  In the cementation step S2, nickel in the solution from which the copper has been fixed and removed becomes divalent nickel ions, and the solution is sent to the next purification step S3 as a final cementation solution. On the other hand, the copper sulfide and unreacted nickel that remain in the solid phase after being immobilized become cementation residues and are sent again to the chlorine leaching step S1. As for cobalt and copper in the nickel mat, unreacted substances are sent as a cementation residue to the chlorine leaching step S1 by the same reaction as nickel, and metal ions are sent as a cementation final solution to the cleaning step S3.

  For example, the cementation step S2 may be divided into a first cementation step S2A and a second cementation step S2B. Specifically, in the first cementation step S2A, nickel mixed sulfide (MS) is added to the nickel chloride solution sent from the chlorine leaching step S1, and the reducing power of the nickel mixed sulfide is reduced. Thus, divalent copper ions are reduced to monovalent copper ions. Next, in the second cementation step S2B, nickel mat and chlorine leaching residue are added to the produced slurry, and monovalent copper ions are sulfided together with chlorine leaching residue which is a sulfur source by the nickel mat, such as copper sulfide. As a product, the copper in the nickel chloride solution is removed. Thus, by performing the copper cementation process in two stages, the copper circulating in the system can be removed more efficiently with a predetermined amount of nickel matte, Copper can be more reliably removed from the nickel solution.

[Purification process]
In the liquid purification step S3, the cementation final solution is fed from the cementation step S2, and for example, other than nickel such as iron, cobalt, copper, etc. contained in the final cementation liquid by a liquid purification treatment such as an oxidation neutralization method. Remove impurities. For example, the liquid purification step S3 includes a deironing step, a decobalt step, a deleading step, and a dezincing step as main steps.

  More specifically, in these treatment steps in the liquid purification step S3, for example, chlorine gas as an oxidizing agent and carbonate as an alkaline agent are used as a method for removing impurities from the nickel leachate which is a cementation final solution. An oxidation neutralization method can be used. The oxidation neutralization method uses 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 is a method widely used for wastewater treatment and the like. In addition, regarding the chemical | medical agent used for an oxidation neutralization method, hypochlorous acid, oxygen, air other than chlorine gas can be used as an oxidizing agent, and caustic soda etc. other than carbonate are used as an alkaline agent. Hydroxides, ammonia and the like can be used.

For example, in the liquid purification process S3, impurities are removed by a 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 this reaction formula, in the liquid purification step S3, a hydroxide precipitate of the target impurity is formed from the nickel leachate using chlorine gas, and a nickel chloride solution from which the impurity has been removed is obtained.

[Electrolysis process]
In the electrolysis step S4, electronickel is produced by an electrowinning method using the nickel chloride solution obtained through the liquid purification step S3. In the electrolysis step S4, nickel ions in the nickel chloride solution are deposited as metal on the cathode side, and electric nickel is generated. On the other hand, on the anode side, chlorine ions in the nickel chloride solution are generated as chlorine gas and used in the chlorine leaching step S1 and the like.

Specifically, in the electrolysis step S5, reactions shown in the following (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)

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

≪2. Leaching control system for chlorine leaching process >>
<2-1. First Embodiment>
FIG. 3 is a configuration diagram of a leaching control system in the chlorine leaching reaction tank in the above-described chlorine leaching step S1 according to the first embodiment. In the present embodiment, the chlorine leaching reaction in the chlorine leaching step S1 is performed as No. 0A tank, no. 0B tank, No. 1-No. An example is given of a case where the reaction is carried out in 3 tanks, 5 tanks in total (see FIG. 2). It is a leaching control system configuration diagram in the 0A tank. The leaching control of the 0A tank will be specifically described.

  As shown in FIG. 3, in the leaching control system in the chlorine leaching reaction tank 11, a chlorine gas supply for supplying chlorine gas required for leaching to a reaction tank (No. 0A tank) 11 for leaching metal with chlorine gas. A part 12, an MS supply part 13 that supplies nickel mixed sulfide (MS) as a raw material to be leached, and a CMR addition part 14 that adds cementation residue (CMR) are configured.

[Chlorine leaching reaction tank (No. 0A tank)]
The chlorine leaching reaction tank 11 is a reaction tank that contains a nickel mixed sulfide (MS) slurry as a raw material and causes a leaching reaction in which a metal such as Ni contained in the MS is leached by chlorine gas. A slurry of cementation residue (CMR) produced in the above-described cementation step S2 is also supplied as a raw material to the reaction tank 11 as appropriate, and chlorine gas blown in while stirring the slurry by the stirring mechanism 11a. Reacts with the metal component to leach out to form a chlorine leachate (nickel chloride solution) in which the metal component is leached.

  In the chlorine leaching reaction tank 11, a chlorine gas supply pipe 52 for supplying chlorine gas is provided in the reaction tank 11 for leaching a metal such as Ni contained in the raw material as described above with chlorine gas. ing. In addition, an MS supply pipe 53 for supplying MS as a main raw material and a CMR addition pipe 54 for adding CMR are provided. As will be described in detail later, in the present embodiment, the MS processing amount to be processed in the reaction tank 11 is determined based on the amount of chlorine gas blown, and the CMR addition amount is determined in accordance with the ORP, Each is charged into the reaction tank 11 from the supply pipes 52, 53 and 54.

  Further, the chlorine leaching reaction tank 11 is provided with an ORP measurement unit 15 for measuring the oxidation-reduction potential (ORP) of the processing solution in the reaction tank. The ORP measurement unit 15 measures the ORP during the leaching reaction, and detects the variation of the ORP with time.

  As will be described in detail later, a signal related to the measured ORP value is transmitted to the CMR addition unit 14, and the CMR addition unit 14 controls the amount of CMR addition based on the received signal.

[Chlorine gas supply section]
The chlorine gas supply unit 12 supplies chlorine gas necessary for the leaching reaction of metal components contained in raw materials such as MS in the chlorine leaching reaction tank 11. Here, as the chlorine gas supplied from the chlorine gas supply unit 12, the chlorine gas generated from the anode side in the electrolysis step S4 in the electric nickel production process is recovered and used. Therefore, the amount of chlorine gas that can be supplied from the chlorine gas supply unit 12 (chlorine gas blowing amount) is determined based on the amount of chlorine gas recovered from the electrolysis step S4.

  The chlorine gas supply unit 12 includes a chlorine gas detection unit 21 that detects the amount of chlorine gas blown into the chlorine leaching reaction tank (No. 0A tank) 11 and a total flow rate calculation unit 16 that recognizes the detected amount of blown gas and that will be described later. An instruction control unit 22 for instructing the blowing of chlorine gas into the chlorine leaching reaction tank (No. 0A tank) 11 and a bypass valve 23 for controlling the on / off of the blowing are provided. The bypass valve 23 is connected to a chlorine gas supply pipe 52, and a predetermined amount of chlorine gas is supplied to the chlorine leaching reaction tank 11.

  The chlorine gas supply unit 12 includes Detecting the amount of chlorine gas blown in four reaction tanks other than the chlorine leaching reaction tank 11 in the 0A tank, the amount of chlorine gas blowing in the chlorine leaching reaction tank (No. 0A tank) 11 and the chlorine gas in all other reaction tanks A total flow rate calculation unit 16 that calculates a total value with the flow rate is connected.

  Here, in the total flow rate calculation unit 16, as described above, no. 0A tank, no. 0B tank, No. 1-No. A signal relating to the amount of chlorine gas blown into each of the three reaction tanks of three tanks is sent, and the total flow rate of chlorine gas blown into the five reaction tanks is calculated. The calculated total flow rate of chlorine gas blow is notified to the MS supply unit 13 to be described later, and the MS throughput to be processed in each reaction tank by the MS supply unit 13 based on the notified chlorine gas blow amount. It is determined. Thus, in the present embodiment, the determination of the amount of chlorine gas blown and the amount of MS treatment is not independently determined and controlled, but based on the amount of chlorine gas blown in the entire chlorine leaching step S1. The amount of MS to be processed is determined. The flow of determination of the MS processing amount based on the chlorine gas blowing amount will be described in detail later.

[MS supply section]
The MS supply unit 13 supplies nickel mixed sulfide (MS) as a raw material to be leached in the chlorine leaching reaction tank 11. Here, as described above, the nickel mixed sulfide to be supplied contains a large amount of Ni and Cu, and a high amount mainly of Ni and Cu is obtained by a chlorine leaching reaction in which chlorine gas is applied to this MS. A concentrated chloride solution is obtained. Note that the MS supply unit 13 supplies the chlorine leaching reaction tank 11 with MS that has been repulped and slurried with, for example, a nickel chloride solution obtained in the electrolysis step S4.

  The MS supply unit 13 includes an MS amount detection unit 31 that detects an MS supply amount to the chlorine leaching reaction tank (No. 0A tank) 11, in other words, an MS processing amount, and a total flow rate calculation unit connected to the chlorine gas supply unit 12. 16 determines the MS processing amount (MS supply amount to be supplied to the chlorine leaching reaction tank 11) based on the total flow rate of chlorine gas blown in the entire chlorine leaching step S1 from 16, an instruction control unit 32 for instructing supply, and ON / OFF of supply And a bypass valve 33 for controlling the control. The bypass valve 33 is connected to the MS supply pipe 53 so that the supply amount of MS controlled by the instruction control unit 32 is supplied to the chlorine leaching reaction tank 11.

  Specifically, in the instruction control unit 32, when a signal related to the total flow rate of chlorine gas blown in the entire chlorine leaching step S1 is sent from the total flow rate calculation unit 16 and received, the total flow rate calculation unit 16 determines whether the total flow rate of chlorine leaching step S1 The MS throughput (total MS throughput) is determined, and the MS throughput for each reaction vessel is determined from the total MS throughput. At this time, the MS processing amount for each reaction tank (in FIG. 3, the MS processing amount in the chlorine leaching reaction tank 11) is the total MS processing amount and the chlorine leaching reaction tank (No. 0A tank) with respect to the total flow rate of chlorine gas blowing. 11 is distributed and determined from the total MS processing amount based on the ratio of the amount of chlorine gas supplied to 11 (the amount detected by the chlorine gas detector 21).

  A notification regarding the determined MS throughput is sent from the instruction control unit 32 to the MS amount detection unit 31 and the bypass valve 33, and the determined predetermined amount of MS is supplied to the chlorine leaching reaction tank 11. Thus, in the present embodiment, the MS amount in each reaction tank is determined based on the amount of chlorine gas blown in, and supplied to the reaction tank 11.

  In the MS supply unit 13, the MS processing amount supplied to the reaction tank 11 may be determined in consideration of the ORP value measured in the chlorine leaching reaction tank 11.

[CMR addition part]
The CMR addition unit 14 supplies a predetermined amount of cementation residue (CMR) to the chlorine leaching reaction tank 11. Here, the cementation residue to be supplied is a product obtained in the cementation step S2 in the electric nickel manufacturing process described above, and is generated by a reaction for fixing copper contained in the copper-containing nickel chloride solution which is a chlorine leaching solution. Solid precipitate. The cementation residue contains immobilized copper and unreacted nickel, and the slurry of the cementation residue is fed to the chlorine leaching step S1.

  The CMR addition unit 14 includes a CMR amount detection unit 41 that detects a CMR addition amount with respect to the chlorine leaching reaction tank (No. 0A tank) 11 and a CMR addition amount based on the ORP value measured in the chlorine leaching reaction tank 11. An instruction control unit 42 for determining and instructing addition is provided, and a bypass valve 43 for controlling ON / OFF of addition is provided. The bypass valve 43 is connected to the CMR addition pipe 54 so that an addition amount of CMR that is command-controlled by the command control unit 42 is added to the chlorine leaching reaction tank 11.

  Here, in order to maintain the leaching rate of the chlorine leaching reaction in the chlorine leaching step S1, it is important to maintain the oxidation-reduction potential (ORP) in a certain region as an environment for leaching the metal. It is known that the ORP as the leaching environment has an optimum region specific to the raw material. Specifically, the optimum region in the leaching reaction of the nickel mixed sulfide which is the main raw material is in the range of 470 mV to 470 mV. This ORP value is obtained when the liquid temperature in the reaction vessel is 110 ° C., the pH is −1, and the reference electrode is Ag / AgCl.

  As described above, the optimum value of ORP is determined by the relationship with the Cu ion concentration. Therefore, maintaining the ORP within a certain range means that the Cu ion concentration in the reaction solution is stable. On the contrary, if the Cu concentration in the reaction solution fluctuates, the ORP shows a value deviating from the optimum region, which indicates that the leaching rate is lowered. When the ORP in the reaction vessel fluctuates with the fluctuation of the Cu ion concentration, the ORP can be corrected to the optimum value by adjusting the amount of CMR added.

  Also in the present embodiment, in the CMR addition unit 14, when the instruction control unit 42 receives a signal related to the ORP value (variation of the ORP value with time) measured in the chlorine leaching reaction tank 11, the CMR addition unit 14 is based on the ORP value. Then, determine the amount of CMR added and instruct supply. Then, a notification regarding the determined CMR addition amount is sent from the instruction control unit 42 to the CMR amount detection unit 41 and the bypass valve 43, and the determined predetermined amount of CMR is supplied to the chlorine leaching reaction tank 11.

  Also in the prior art, when the ORP of the solution in the chlorine leaching reaction tank fluctuates with the fluctuation of the Cu ion concentration, the ORP is corrected to the optimum value by adjusting the amount of CMR added. . However, even if the ORP is temporarily restored to the optimum region by the addition of CMR, the Cu ion concentration in the whole system will eventually change again due to the circulation in the system of the solution (see FIG. 8), and the ORP will eventually reach the optimum region. It was difficult to stabilize.

  In contrast, in the ORP control system according to the present embodiment, as described above, the amount of chlorine gas blown in and the determination of the MS processing amount are not independently controlled, but the amount of chlorine gas blown in is blown in. Based on the above, the amount of MS to be processed in the entire chlorine leaching step S1 is determined, and the amount of CMR added is determined and added in accordance with the ORP fluctuation caused by the leaching reaction caused by this. According to such a configuration, the ORP can be stably maintained in the optimum region range, and can be maintained constant at a desired leaching rate.

<2-2. Second Embodiment>
FIG. 4 is a configuration diagram of a leaching control system in the chlorine leaching reaction tank in the above-described chlorine leaching step S1 according to the second embodiment. In the second embodiment, the chlorine leaching reaction in the chlorine leaching step S1 is also performed as No. 0A tank, no. 0B tank, No. 1-No. A case where the reaction is performed in three reaction tanks in a total of five tanks is taken as an example (see FIG. 2), and FIG. It is a block diagram of the leaching control system of 0A tank.

  As shown in FIG. 4, in the leaching control system according to the second embodiment, the addition of CMR from the CMR adding unit 14 is compared with the leaching control system according to the first embodiment described above (see FIG. 3). In addition to determining the amount of CMR added from the CMR addition unit 14 based on the ORP value measured in the chlorine leaching reaction tank 11, the amount of MS supplied to the chlorine leaching reaction tank 11 (MS throughput) and Referring to the balance (the ratio between the MS supply amount and the CMR addition amount), the difference is that control for determining the CMR addition amount is performed.

  Specifically, in the CMR addition unit 14 for adding CMR, the instruction control unit 42 uses the ORP value (time-lapse ORP value) measured in the chlorine leaching reaction tank 11 in the same manner as in the first embodiment. And a signal related to the MS supply amount (MS processing amount in the chlorine leaching reaction tank 11) determined by the instruction control unit 32 of the MS supply unit 13 is received and received. Yes. The reception control of each signal is performed by the switch control unit 61, and a signal regarding the ORP value from the chlorine leaching reaction tank 11 and a signal regarding the MS supply amount from the instruction control unit 32 of the MS supply unit 13 are CMR. It is surely sent to the instruction control unit 42 of the adding unit 14.

  As described above, the amount of CMR added from the CMR addition unit 14 is determined based on not only the ORP value measured in the chlorine leaching reaction tank 11 but also the MS supply amount supplied to the chlorine leaching reaction tank 11. As a result, it is possible to control in consideration of the amount of MS to be processed and the addition balance of Cu in the supplied CMR, and it is possible to maintain the ORP in the optimum region range even more stably. Thus, it is possible to maintain a constant leaching rate as desired.

  In the control system configuration diagram shown in FIG. 4, the same components as those in the control system shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted here.

≪3. Leaching control method in chlorine leaching process >>
<3-1. First Embodiment>
Next, the flow of the leaching control method in the chlorine leaching step S1 based on the leaching control system configuration shown in FIG. 3 will be described. FIG. 5 is a flowchart showing the flow of the leaching control method according to the first embodiment.

  As the chlorine gas used for chlorine leaching in the chlorine leaching reaction tank 11, the chlorine gas obtained from the anode side in the electrolysis step S4 in the electric nickel production process is used. Therefore, first, in step S101, the amount of chlorine gas supplied to the chlorine leaching reaction tank (No. 0A tank) 11 is detected based on the amount of chlorine gas recovered from the electrolysis step S4. The chlorine gas amount is detected by the chlorine gas detection unit 21 in the chlorine gas supply unit 12.

  Next, in step S102, the amount of chlorine gas supplied to the chlorine leaching reaction tank (No. 0A tank) 11 and the other reaction tanks (No. 0B tank, No. 1 to No. 3 tank) are supplied. The total amount of chlorine gas blown in the chlorine leaching step S1 is calculated by adding the amount of chlorine gas. The total flow rate of the chlorine gas blow-in is calculated by the total flow rate calculation unit 16.

  Next, in step S103, the MS processing amount (total MS processing amount) in the entire chlorine leaching step S1 is determined based on the calculated total flow rate of chlorine gas blowing. Subsequently, in step S104, the MS throughput for each reaction vessel is determined from the total MS throughput in the determined chlorine leaching step S1 as a whole. Here, the MS throughput in the chlorine leaching reaction tank 11 is determined. The determination of the total MS throughput and the determination of the MS throughput for each reaction tank in step S103 and step S104 are performed by the instruction control unit 32 of the MS supply unit 13.

  Next, in step S <b> 105, the determined MS processing amount is instructed and controlled by the instruction control unit 32, and that amount of MS is supplied to the chlorine leaching reaction tank 11. On the other hand, in step S <b> 106, chlorine gas is blown into the chlorine leaching reaction tank 11 from the chlorine gas supply unit 12.

  Next, in step S107, the ORP value in the chlorine leaching reaction tank 11 is measured. The measurement of the ORP value here is preferably performed continuously every predetermined time so that the temporal ORP fluctuation can be confirmed.

  Next, in step S108, the amount of CMR added is determined based on the measured ORP value (variation in ORP value over time). Determination of the CMR addition amount based on the ORP value is performed by the instruction control unit 42 in the CMR addition unit 14.

  In step S 109, the determined CMR addition amount is instructed and controlled by the instruction control unit 42, and that amount of CMR is added to the chlorine leaching reaction tank 11.

  As described above, in the ORP control method according to the present embodiment, the amount of MS to be processed in the entire chlorine leaching step S1 and the amount of MS to be processed in each reaction tank are determined based on the amount of chlorine gas blown in. The amount of CMR added is determined and added in accordance with the ORP fluctuation caused by the leaching reaction caused by this. According to such a configuration, the ORP can be stably maintained in the optimum region range, and the leaching efficiency can be improved by maintaining the leaching rate at a desired level.

  Specifically, FIG. 6A shows an ORP measurement result when the chlorine leaching process is performed in the chlorine leaching step S1 based on the leaching control system configuration according to the present embodiment. This graph shows the variation of the ORP value with the horizontal axis as time (elapsed time of one day). From the graph of FIG. 6 (A), the ORP value in the reaction vessel 11 can be accurately controlled within the range of only 4 mV from 458 mV to 462 mV by the leaching control system and the leaching control method according to this embodiment. Is clearly understood. Thus, according to this leaching control system and leaching control method, it is possible to stably control the ORP within the optimum range for leaching the nickel mixed sulfide, whereby Ni or the like from the raw material can be controlled. The metal leaching rate can be stabilized.

  On the other hand, FIG. 6 (B) shows a chlorine leaching reaction performed by a configuration (see FIG. 9) in which chlorine gas injection and determination of MS throughput are controlled independently as in the prior art. It shows an ORP measurement result. As shown in FIG. 6B, it can be seen that the ORP value fluctuates greatly (fluctuation range: 20 mV or more) in the conventional configuration, and the leaching rate of metal such as Ni from the raw material is stabilized. It is expected not to be possible.

<3-2. Second Embodiment>
FIG. 7 is a flowchart for explaining the flow of the leaching control method in the chlorine leaching step S1 based on the control system configuration according to the second embodiment shown in FIG. As described above, in the control system (see FIG. 4) according to the second embodiment, the amount of CMR added based on the ORP value measured in the chlorine leaching reaction tank 11 regarding the addition of CMR from the CMR addition unit 14. The CMR addition amount is determined with reference to the balance (the ratio between the MS supply amount and the CMR addition amount) with the MS supply amount (MS treatment amount) supplied to the chlorine leaching reaction tank 11 as well. It differs in that it performs control.

  First, in step S101, the amount of chlorine gas supplied to the chlorine leaching reaction tank (No. 0A tank) 11 is detected based on the amount of chlorine gas recovered from the electrolysis step S4 (chlorine gas detector 21).

  Next, in step S102, the amount of chlorine gas supplied to the chlorine leaching reaction tank (No. 0A tank) 11 and the other reaction tanks (No. 0B tank, No. 1 to No. 3 tank) are supplied. The total amount of chlorine gas blown in the chlorine leaching step S1 is calculated by adding the amounts of chlorine gas (total flow rate calculation unit 16).

  Next, in step S103, the MS processing amount (total MS processing amount) in the entire chlorine leaching step S1 is determined based on the calculated chlorine gas blowing total flow rate, and subsequently, the determined chlorine leaching step in step S104. The MS processing amount for each reaction tank (here, the MS processing amount in the chlorine leaching reaction tank 11) is determined from the total MS processing amount in the entire S1 (instruction control unit 32 in the MS supply unit 13).

  Next, in step S105, the determined MS throughput is instructed and controlled by the instruction control unit 32, and MS is supplied to the chlorine leaching reaction tank 11. On the other hand, in step S <b> 106, chlorine gas is blown into the chlorine leaching reaction tank 11 from the chlorine gas supply unit 12.

  Next, in step S107, the ORP value in the chlorine leaching reaction tank 11 is measured.

  Next, in step S108, in the second embodiment, the amount of CMR added is controlled based on the measured ORP value (variation of the ORP value over time), while in step S109, it is determined in step S104. The MS treatment amount (MS treatment amount in the chlorine leaching reaction tank 11) is notified, and the CMR addition amount is controlled in consideration of the ratio between the MS supply amount and the CMR addition amount from the viewpoint of the supplied MS amount.

  In step S110, based on the control of the CMR addition amount in steps S108 and S109, the instruction control unit 42 in the CMR addition unit 14 determines the CMR addition amount, and adds that amount of CMR to the chlorine leaching reaction tank 11. To do.

11 Chlorine leaching reaction tank (reaction tank)
DESCRIPTION OF SYMBOLS 12 Chlorine gas supply part 13 MS supply part 14 CMR addition part 15 ORP measurement part 16 Total flow calculation part 21 Chlorine gas detection part 22 Instruction control part 23 Bypass valve 31 MS amount detection part 32 Instruction control part 33 Bypass valve 41 CMR quantity detection Unit 42 Instruction control unit 43 Bypass valve 52 Chlorine gas supply piping 53 MS supply piping 54 CMR addition piping 61 Switch control unit

Claims (3)

A chlorine leaching process for obtaining a chlorine leaching solution in which a metal component is leached by performing a chlorine leaching treatment with a chlorine gas on nickel mixed sulfide in a reaction vessel;
A cementation step of immobilizing copper contained in the chlorine leaching solution obtained by the chlorine leaching treatment to obtain a cementation final solution and a cementation residue;
An electrolysis process for producing electric nickel and chlorine gas by electrolytic treatment after performing a liquid purification treatment on the final cementation liquid, and a leaching control system in the chlorine leaching step in the manufacturing process of electric nickel There,
A chlorine gas supply unit for supplying chlorine gas into the reaction vessel;
A raw material supply unit for supplying the nickel mixed sulfide as a raw material into the reaction layer;
A cementation residue addition unit for adding the cementation residue obtained in the cementation step into the reaction vessel,
A plurality of the reaction vessels are provided,
In the chlorine gas supply unit, the total amount of chlorine gas blown into the plurality of reaction vessels in the chlorine leaching step is summed to calculate the total flow rate of chlorine gas ,
In the raw material supply unit, based on the total flow rate of the chlorine gas calculated in the chlorine gas supply unit, the amount of nickel mixed sulfide to be subjected to chlorine leaching treatment in one reaction tank is determined, and the inside of the reaction tank To supply the treated amount of nickel mixed sulfide,
In the cementation residue addition unit, the amount of cementation residue added to the reaction vessel is determined based on the measurement result of the oxidation-reduction potential in the reaction vessel, and the amount of cementation residue in the reaction vessel is determined. A leaching control system characterized by the addition of   In the cementation residue addition unit, along with the measurement result of the oxidation-reduction potential in the reaction vessel, the treatment amount of the cementation residue to the reaction vessel is determined based on the treatment amount of the nickel mixed sulfide determined in the raw material supply unit. The leaching control system according to claim 1, wherein an addition amount is determined, and the addition amount of cementation residue is added to the reaction vessel. A chlorine leaching process for obtaining a chlorine leaching solution in which a metal component is leached by performing a chlorine leaching treatment with a chlorine gas on a nickel mixed sulfide in a plurality of reaction vessels;
A cementation step of immobilizing copper contained in the chlorine leaching solution obtained by the chlorine leaching treatment to obtain a cementation final solution and a cementation residue;
An electrolysis step of producing electrolytic nickel and chlorine gas by electrolytic treatment after performing a liquid purification treatment on the cementation final solution, and a leaching control method in the chlorine leaching step in the manufacturing process of electrical nickel There,
A first step of calculating a total flow rate of chlorine gas by adding together the amounts of chlorine gas blown into the plurality of reaction vessels in the chlorine leaching step;
A second step of determining the amount of nickel mixed sulfide to be subjected to chlorine leaching treatment in one reaction tank based on the calculated total flow of chlorine gas;
Determined based on the processing amount of the nickel mixed sulphide, a third step of supplying the processing amount of the nickel mixed sulphide to the reaction vessel,
A fourth step of measuring a redox potential in the reaction vessel;
Based on the measured oxidation-reduction potential, the addition amount of the cementation residue obtained in the cementation step is determined, and a fifth step of adding the addition amount of cementation residue to the reaction vessel;
A leaching control method characterized by comprising:

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