WO2014136487A1 - Hydrometallurgical plant for nickel oxide ore and method for operating said hydrometallurgical plant - Google Patents

Abstract

The present invention makes it possible to increase the throughput in ore processing and thus attain enhanced productivity without causing poor reaction or deterioration in operation efficiency. This hydrometallurgical plant (10) is provided with: a leaching system (11) which is composed of multiple leaching lines that have leaching tanks (11_(n)) respectively and in which the leaching of an ore is conducted; a preliminary neutralization system (12) which is equipped with first- and second-stage neutralization tanks and in which the pH of a leach slurry is adjusted; and a solid-liquid separation system (13) which is composed of one separation line and in which the pH-controlled leach slurry discharged from the preliminary neutralization system (12) is separated into a solid and a liquid. The preliminary neutralization system (12) is configured in a manner such that: multiple first-stage neutralization tanks (12A_(n)) are arranged so as to correspond respectively to the leaching tanks (11_(n)) of the multiple leaching lines; and the leach slurry streams, the pH values of which have been adjusted in the first-stage neutralization tanks (12A_(n)), are joined in a single line which is composed of one second-stage neutralization tank (12B). The joined leach slurry streams are transferred to the solid-liquid separation system (13).

Description

Nickel oxide ore hydrometallurgical plant and method of operating the hydrometallurgical plant

The present invention relates to a nickel oxide ore wet smelting plant that recovers nickel and cobalt from nickel oxide ore, and an operation method of the wet smelting plant. This application claims priority on the basis of Japanese Patent Application No. 2013-046986 filed on March 8, 2013 in Japan. This application is incorporated herein by reference. Incorporated.

Recently, high-pressure acid leaching using sulfuric acid (High Pressure Acid 注目 Leach) has attracted attention as a hydrometallurgical method for nickel oxide ore. Unlike the conventional dry smelting method, which is a conventional nickel oxide ore smelting method, this method does not include dry processes such as reduction and drying processes, and is a consistent wet process. Is advantageous. Further, in this method, a sulfide containing nickel and cobalt whose nickel quality is increased to about 50% by mass (hereinafter also referred to as “nickel / cobalt mixed sulfide” or “Ni / Co mixed sulfide”) is obtained. Has the advantage of being able to

The hydrometallurgical method of nickel oxide ore using this high pressure acid leaching method has processes as shown in the simplified process diagram of FIG. That is, an ore processing step in which nickel oxide ore is pulverized to a predetermined size to form a slurry, a sulfuric acid is added to the ore slurry to perform a leaching treatment under high temperature and high pressure (high pressure acid), and a leaching slurry. A pre-neutralization step in which neutralization (hereinafter also referred to as “pre-neutralization”) treatment is performed before multi-stage washing, and the leach residue and nickel are washed while multi-stage washing is performed on the leach slurry obtained by the pre-neutralization treatment. And a solid-liquid separation process (hereinafter also referred to as “CCD process”) for solid-liquid separation into a leachate containing an impurity element together with cobalt, and a neutralized starch containing the impurity element by adjusting the pH of the obtained leachate A neutralization step for obtaining a neutralized final solution containing zinc together with nickel and cobalt, and dezincification for forming a nickel sulfide by adding a sulfiding agent to the neutralized final solution to obtain a nickel recovery mother liquor Process and nickel times A nickel recovery process that forms a mixed sulfide containing nickel and cobalt by adding a sulfiding agent to the mother liquor, and a neutralization treatment is performed by mixing the waste liquid (poor liquid) in the nickel recovery process and the residue from the CCD process. A final neutralization step (see, for example, Patent Documents 1 and 2).

In the pre-neutralization step in the above-described hydrometallurgy, the leaching slurry obtained from the leaching step is adjusted to a pH at which cleaning can be performed efficiently during the multi-stage cleaning process in the next CCD step. Specifically, the pH of the leaching slurry is adjusted by charging the leaching slurry into a neutralization tank and adding a neutralizing agent such as calcium carbonate.

The pre-neutralized leaching slurry is then separated into a leaching solution and an leaching residue containing impurity elements together with nickel and cobalt while being subjected to multi-stage cleaning in a CCD process. The separated leachate is sent to the neutralization step to become a neutralization final solution, and the leach residue is sent to the final neutralization step for processing.

In the dezincing process, the neutralized final solution is charged into the sulfurization reactor, and zinc sulfide, copper, etc. in the neutralized final solution are converted to sulfide by adding a sulfurizing agent such as hydrogen sulfide gas or sodium hydrosulfide. . After the sulfiding treatment, a nickel recovery mother liquor from which zinc sulfide has been removed is obtained by solid-liquid separation using a filter press or the like.

By the way, when designing a hydrometallurgical plant of nickel oxide ore, when the ore processing amount (or planned production amount) is large, it is conceivable to design the plant based on the following two measures, for example. That is,
[I] Make the whole system large (for example, a system of 30,000 tons / year as shown in FIG. 8)
[Ii] Two series of small-scale systems are installed (for example, two systems of 15,000 tons / year are installed as shown in FIG. 9)

However, in the case of [i], it is not sufficient to industrially simply increase the equipment size, particularly in the design of the leaching treatment equipment for performing the leaching process. In other words, in the leaching treatment facility, it is necessary to sufficiently consider the viewpoint of reactivity that a predetermined leaching reaction must be efficiently and effectively caused to leach valuable metal at a high leaching rate. Become. In addition, when the facility size is increased as described above, there is a problem from the viewpoint of economy that the cost for repairing as necessary increases. Therefore, it is very difficult in practice to increase the size of equipment simply industrially, and 10,000 tons / year to 15,000 tons / year with a proven track record (leaching slurry production in terms of nickel) It is desirable to configure the equipment with a scale of

Also, in the case of [ii], the number of equipment is naturally increased by using a plurality of systems, and the equipment investment cost becomes very large. Moreover, in order to perform efficient smelting operation, since connection piping for mutually transferring a process liquid (process liquid) between each series is also needed (for example, refer patent document 3), cost. Becomes even larger.

Thus, as a compromise of the measures [i] and [ii] described above, for example, it is easily recalled that a plant is designed based on the following measures. That is,
[Iii] The upper process is two series (plural series) and the subsequent lower process is one series (for example, as shown in FIG. 10, the upper process up to the pre-neutralization process is made into two series, and the lower process after the CCD process. And a system of 30,000 tons / year)

However, in the wet refining method of nickel oxide ore, which stage is preferably divided into the above-mentioned upper process and lower process, and it is given to efficient operation resulting from the merge in the lower process There are no known issues.

In this way, when it is designed to be divided into a plurality of upper processes and a single lower process, the process liquid transferred from each of the upper processes (for example, leaching slurry) is There is a possibility that variations occur, and a non-uniform process liquid is transferred to a lower process consisting of a single series. In such a case, the reaction conditions in the processing equipment in the lower process are not uniform, so that efficient operation is impossible, and there is a possibility of causing a reaction failure and affecting product quality.

Furthermore, if a trouble such as a leaching failure in the leaching process occurs in one of the upper processes made up of a plurality of processes, or a start-up operation after the operation is stopped, a defect occurs in the other processes. Even if it is not, there is a problem that the entire plant is forced to stop because it joins in the lower process to make one line, and the operation efficiency is remarkably deteriorated.

For example, in Patent Document 3, in a plant having a plurality of the same processes, even if there is a trouble or the like in a predetermined process on a series of processes by connecting processing facilities in a predetermined process with piping. A technique for minimizing a decrease in operation efficiency is disclosed, which is a very effective technique in actual operation. However, for the reasons described above, when the upper process is operated in two lines, and then a plant that merges and becomes a single line in the lower process is targeted, the technique described in Patent Document 3 is used as it is. It cannot be applied.

Japanese Patent Laid-Open No. 06-116660 JP-A-2005-350766 JP 2011-225908 A

The present invention has been proposed in view of such circumstances, and is a nickel oxide ore capable of improving productivity by increasing the amount of ore treatment without causing a reaction failure or deterioration in operation efficiency. An object of the present invention is to provide a wet smelting plant and an operation method thereof.

The inventors of the present invention have made extensive studies in order to achieve the above-described object. As a result, in the pre-neutralization facility for pre-neutralizing the leaching slurry obtained after the leaching treatment, the neutralization tank is provided in two stages, and the first stage neutralization tanks are arranged in a plurality of series. And it discovered that the subject mentioned above could be solved by making the neutralization processing tank of a 2nd step into a single series.

That is, the hydrometallurgical plant for nickel oxide ore according to the present invention includes at least a leaching facility including a plurality of leaching treatment tanks for leaching the nickel oxide ore and a two-stage neutralization treatment tank, and the leaching treatment described above. Pre-neutralization equipment that performs pre-neutralization to adjust the pH of the leached slurry discharged from the tank to a predetermined range, and a single series, the leached slurry discharged from the pre-neutralization equipment after pH adjustment, A solid-liquid separation facility for solid-liquid separation into a leachate and a leach residue in a solid-liquid separation tank. In the preliminary neutralization facility, the first stage neutralization tank is a leach provided in the leaching facility. A plurality of series are provided so as to correspond to each series of treatment tanks, and the second stage in which the leaching slurry adjusted in pH in each series of neutralization treatment tanks constituting the first stage consists of a single series So as to join the neutralization tank Made which are, leached slurry joins the neutralization tank of the second stage, characterized in that it is transferred to the solid-liquid separation equipment.

The operation method of the nickel oxide ore hydrometallurgical plant according to the present invention is an operation method of the hydrometallurgical plant for recovering nickel and cobalt from the nickel oxide ore, the hydrometallurgy of the nickel oxide ore. The plant includes at least a leaching facility including a plurality of leaching treatment tanks for leaching the nickel oxide ore and a two-stage neutralization treatment tank, and the pH of the leaching slurry discharged from the leaching treatment tank is within a predetermined range. A pre-neutralization facility that performs pre-neutralization to be adjusted, and a single series of leaching slurry that has been pH-adjusted and discharged from the pre-neutralization facility are separated into a leaching solution and a leaching residue in a solid-liquid separation tank. In the preliminary neutralization facility, a plurality of first-stage neutralization treatment tanks correspond to each series of leaching treatment tanks provided in the leaching equipment. The second stage neutralization treatment tanks are arranged in a single series, and the leach slurry discharged from each neutralization treatment tank in the first stage is formed from the single series. It is made to merge with the 2nd-stage neutralization processing tank, and the leached slurry which joined is transferred to the said solid-liquid separation equipment, It is characterized by the above-mentioned.

In the nickel oxide ore hydrometallurgical plant according to the present invention, the pre-neutralization equipment for pre-neutralizing the leaching slurry is constituted by a two-stage neutralization tank, and the first-stage neutralization tank Is a plurality of series so as to correspond to a plurality of leaching treatment tanks, and the second stage neutralization treatment tank is a single series. As a result, it is possible to increase the amount of ore processing while reducing equipment costs, and to eliminate variations in the leach slurry, which is a process liquid, and to effectively prevent reaction failures and operational efficiency degradation. It becomes.

Moreover, in the hydrometallurgical plant according to the present invention, since the two-stage neutralization tank is provided as described above, the reaction of the first-stage neutralization tank and the processing equipment in other processes. By appropriately providing piping for connecting the tank, for example, at an abnormal time such as when the plant is started up, it does not adversely affect other systems capable of normal operation and while suppressing a decrease in operation efficiency, Efficient start-up operation can be performed.

FIG. 1 is a configuration diagram of a nickel oxide ore hydrometallurgical plant. FIG. 2 is a process diagram of a hydrometallurgical method using high pressure acid leaching of nickel oxide ore. FIG. 3 is a diagram for explaining the flow of operation during normal operation. FIG. 4 is a diagram for explaining the flow of operation for self-circulating transfer from the first-stage neutralization tank to the corresponding leaching tank. FIG. 5 is a diagram for explaining an operation flow for transferring the leach slurry from the first-stage neutralization tank to the final neutralization facility. FIG. 6 is a diagram for explaining an operation flow for transferring the leach slurry from the first-stage neutralization tank to the solid-liquid separation tank. FIG. 7 is a simplified process diagram of a hydrometallurgical method using high pressure acid leaching of nickel oxide ore. FIG. 8 is a simplified process diagram of a hydrometallurgical method using high pressure acid leaching of nickel oxide ore. FIG. 9 is a simplified process diagram of a hydrometallurgical method using high pressure acid leaching of nickel oxide ore. FIG. 10 is a simplified process diagram of a hydrometallurgical method using high pressure acid leaching of nickel oxide ore.

Hereinafter, the nickel oxide ore hydrometallurgical plant according to the present invention and the operation method thereof will be described in detail in the following order 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.
1. 1. Outline of nickel oxide ore hydrometallurgical plant 2. About hydrometallurgy of nickel oxide ore 3. Structure of hydrometallurgical plant and method of operating hydrometallurgical plant 3-1. Basic configuration and operation flow during normal operation 3-2. Configuration for self-circulation and operation flow during self-circulation 3-3. Transfer configuration to final neutralization equipment and operation flow when transferring to final neutralization equipment 3-4. Transfer configuration to solid-liquid separation tank and operation flow at the time of transfer to solid-liquid separation tank 3-5. Transition from non-normal operation to normal operation 3-6. Summary 4. Example

<< 1. Overview of nickel oxide ore hydrometallurgical plant >>
The nickel oxide ore hydrometallurgical plant according to the present embodiment (hereinafter also simply referred to as “wet hydrometallurgical plant”) includes, for example, a leaching process by a high-pressure acid leaching method, a preliminary neutralization process, and a solid-liquid separation. It is for performing the hydrometallurgical operation of the nickel oxide ore which consists of a process (CCD process), a neutralization process, a dezincification process, a sulfurization process, and a final neutralization process (detoxification process).

Specifically, as shown in the block diagram of the hydrometallurgical plant in FIG. 1, the hydrometallurgical plant 10 according to the present embodiment includes at least a leaching treatment tank 11 _{(1 to n)} for leaching nickel oxide ore. _{) With} a plurality of (n) series leaching equipment 11 and a two-stage neutralization tank, and preliminary neutralization to adjust the pH of the leaching slurry discharged from the leaching tank 11 _{(1 to n)} to a predetermined range. A pre-neutralization facility 12 to be performed, and a solid-liquid separation facility 13 that consists of a single series and separates the leached slurry that has been pH adjusted and discharged from the pre-neutralization facility 12 into a solid-liquid separation tank. Is.

In the hydrometallurgical plant 10, the first stage neutralization treatment tank 12 A _{(1 to n) in} the preliminary neutralization equipment 12 is the leaching treatment tank 11 _{(1 to n )} provided in the leaching equipment. _A plurality of (n) series are provided so as to correspond to each series, and a single leaching slurry whose pH is adjusted in each series of neutralization treatment tanks 12A _{(1 to n)} constituting the first stage is provided. It is comprised so that it may join to the neutralization processing tank 12B of the 2nd step | stage which consists of a series. The leached slurry that has joined the second-stage neutralization tank 12B is transferred to the solid-liquid separation facility 13.

In the plant configuration diagram of FIG. 1, as a specific example, the leaching treatment tank 11 _{(1 to n)} and the first stage neutralization treatment tank 12A _{(1 to n)} are provided in two series (n = 2). As shown, the number of sequences is not limited to two.

As described above, the hydrometallurgical plant 10 includes two or more reaction tanks in a series of treatment facilities in a process before the preliminary neutralization process (hereinafter also referred to as “upper process”). In the process after the neutralization process (hereinafter, also referred to as “lower process”), a series of processing equipment is configured from a single series (one series) of reaction vessels. In this way, it is possible to increase the amount of nickel oxide ore while reducing the number of parts and suppressing the equipment cost, using a leaching treatment facility of a size that has been used in the past. The production amount of mixed sulfide (product) can be stably increased.

In addition, according to the hydrometallurgical plant 10, even when the leaching slurry obtained from a plurality of series of treatment facilities has a variation in pH or the like, it is made to merge in the second-stage neutralization treatment tank 12B. Therefore, the variation can be eliminated, and solid-liquid separation processing can be performed in the solid-liquid separation facility 13 as a uniform leaching slurry.

Furthermore, according to the hydrometallurgical plant 10, by appropriately providing piping for connecting the first-stage neutralization treatment tank 12A _{(1 to n)} and the reaction tank of the treatment equipment in other processes, for example, plant operation It is possible to prevent the leaching slurry at the stage where the leaching process, such as immediately after the start, has not progressed sufficiently, from being transferred to the solid-liquid separation process or a subsequent process. Thereby, generation | occurrence | production of the reaction failure in each process, the fall of operational efficiency, etc. can be suppressed effectively.

Hereinafter, the nickel oxide ore wet smelting plant and the operation method of the wet smelting plant according to the present embodiment will be described more specifically.

≪2. About hydrometallurgy of nickel oxide ore >>
First, the nickel oxide ore wet smelting method executed by the hydrometallurgical plant 10 according to the present embodiment will be described. This nickel oxide ore wet smelting method is a hydrometallurgical method of leaching and recovering nickel and cobalt from nickel oxide ore using, for example, a high-pressure acid leaching method (HPAL method).

FIG. 2 shows an example of a process diagram of a hydrometallurgical method using high pressure acid leaching of nickel oxide ore. As shown in FIG. 2, the hydrometallurgical method of nickel oxide ore is a leaching step S1 in which sulfuric acid is added to a slurry of nickel oxide ore and leaching is performed under high temperature and high pressure, and the pH of the obtained leaching slurry is set to a predetermined value. A pre-neutralization step S2 for pre-neutralization to adjust to a range; a solid-liquid separation step S3 for separating a residue while performing multi-stage washing of a pH-adjusted leaching slurry to obtain a leachate containing impurity elements together with nickel and cobalt; Adjusting the pH of the leachate, separating neutralized starch containing impurity elements to obtain a neutralized final solution containing zinc together with nickel and cobalt, and adding a sulfurizing agent to the neutralized final solution The zinc sulfide is generated by the above, and the zinc sulfide is separated and removed to obtain the nickel recovery mother liquor containing nickel and cobalt, and the sulfur recovery agent is added to the nickel recovery mother liquor. And a nickel recovery step S6 described form a mixed sulfide containing Kell and cobalt. Furthermore, this hydrometallurgy method has a final neutralization step S7 for recovering and detoxifying the leaching residue separated in the solid-liquid separation step S3 and the poor liquid discharged in the nickel recovery step S6.

(1) Leaching process (1-1) About leaching process In the leaching process S1, a leaching process using, for example, a high-pressure acid leaching method is performed on the nickel oxide ore. Specifically, sulfuric acid is added to the ore slurry obtained by pulverizing the nickel oxide ore used as a raw material, and the ore slurry is stirred by pressurization under a high temperature condition of 220 to 280 ° C. A leach slurry consisting of the residue is formed.

Nickel oxide ores used in the leaching step S1 are mainly so-called laterite ores such as limonite or saprolite ores. Laterite ore usually has a nickel content of 0.8 to 2.5% by weight and is contained as a hydroxide or siliceous clay (magnesium silicate) mineral. The iron content is 10 to 50% by weight and is mainly in the form of trivalent hydroxide (goethite), but partly divalent iron is contained in the siliceous clay. In the leaching step S1, in addition to such a laterite ore, an oxidized ore containing valuable metals such as nickel, cobalt, manganese, and copper, for example, a manganese nodule that exists in the deep sea bottom is used.

In the leaching process in the leaching step S1, a leaching reaction represented by the following formulas (1) to (3) and a high temperature thermal hydrolysis reaction represented by the following formulas (4) and (5) occur, and nickel, cobalt, etc. Leaching as a sulfate and immobilizing the leached iron sulfate as hematite. However, since the immobilization of iron ions does not proceed completely, the leaching slurry obtained usually contains divalent and trivalent iron ions in addition to nickel, cobalt and the like.

・ Leaching reaction MO + H ₂ SO ₄ → MSO ₄ + H ₂ O (1)
(In the formula, M represents Ni, Co, Fe, Zn, Cu, Mg, Cr, Mn, etc.)
2Fe (OH) ₃ + 3H ₂ SO ₄
→ Fe ₂ (SO ₄ ) ₃ + 6H ₂ O (2)
FeO + H ₂ SO ₄ → FeSO ₄ + H ₂ O (3)
High temperature thermal hydrolysis reaction 2FeSO ₄ + H ₂ SO ₄ + 1 / 2O ₂
→ Fe ₂ (SO ₄ ) ₃ + H ₂ O (4)
Fe ₂ (SO ₄ ) ₃ + 3H ₂ O → Fe ₂ O ₃ + 3H ₂ SO ₄ (5)

The amount of sulfuric acid added in the leaching step S1 is not particularly limited, and an excessive amount that allows iron in the ore to be leached is used. For example, 300 to 400 kg per ton of ore. If the amount of sulfuric acid added per ton of ore exceeds 400 kg, the sulfuric acid cost increases, which is not preferable. In the leaching step S1, the pH of the obtained leaching solution is adjusted to 0.1 to 1.0 from the viewpoint of filterability of the leaching residue containing hematite produced in the subsequent solid-liquid separation step S3. It is preferable to do.

(1-2) About Leaching Facility In the hydrometallurgical plant 10 according to the present embodiment, the leaching process (high pressure acid leaching facility) 11 performs the leaching process in the leaching step S1 described above.

Specifically, as shown in FIG. 1, the leaching equipment 11 in the hydrometallurgical plant 10 includes a plurality of (n) series of leaching treatment tanks 11 _{(1 to n)} for leaching nickel oxide ore (for example, FIG. 1). (N = 2 series) as shown in FIG. Hereinafter, the leaching treatment tank is referred to as “leaching treatment tank 11 _(n) ” when the number of series is not specified. Similarly, a first-stage neutralization tank 12A _{(1 to n), which} will be described later, is also expressed as “neutralization tank 12A _(n) ”.

As each series of leaching treatment tanks 11 _(n) constituting the leaching equipment 11, for example, a high-temperature pressurized container (autoclave) is used. In the leaching treatment tank 11 _(n) , for example, ore slurry transferred from the ore treatment process, that is, a predetermined amount of ore slurry obtained by pulverizing ore to a predetermined particle size is loaded from each charging section. Entered.

Although it does not specifically limit as a magnitude | size of the leaching processing tank 11 _{(n) which} consists of an autoclave etc., The thing of the magnitude | size comparable as what has been conventionally used for operation can be used. For example, a leaching slurry having a production amount of 1 million tons / year to 2 million tons / year in terms of nickel can be used. Thus, by using a leaching facility equipped with a plurality of leaching treatment tanks conventionally used, the amount of nickel oxide ore can be increased, and the nickel-cobalt mixed sulfide obtained through a subsequent process Production volume can be increased.

Here, although the details will be described later, in the loading section of the leaching tank 11 _(n), the first stage of the neutralization treatment tank 12A constituting its leaching vessel 11 _(n) a preliminary neutralizing facility 12 _(n) and can be connected to pipe _{21 (n)} connecting the. The pipe 21 _(n) is a pipe that connects the leaching treatment tank 11 _(n) and the first-stage neutralization treatment tank 12A _(n) in the same series. This piping 21 _(n) causes the transfer pump 31 to circulate (self-circulate) the leaching slurry discharged from the first neutralization treatment tank 12A _(n) to the same leaching treatment tank 11 _(n). This is so-called self-circulation piping. The operation for self-circulation will be described in detail later.

(2) Pre-neutralization step (2-1) Pre-neutralization treatment In the pre-neutralization step S2, the pH of the leaching slurry obtained in the leaching step S1 is adjusted to a predetermined range. In the leaching step S1 in which the leaching process by the high-pressure acid leaching method described above is performed, excess sulfuric acid is added from the viewpoint of improving the leaching rate. Therefore, the obtained leaching slurry contains free sulfuric acid (excess sulfuric acid not involved in the leaching reaction), and its pH is very low. Therefore, in the pre-neutralization step S2, the pH of the leaching slurry is adjusted to a predetermined range so that the washing is efficiently performed at the time of the multi-stage washing in the next solid-liquid separation step S3.

Specifically, it is preferable that the leaching slurry used for the cleaning treatment is adjusted to a pH of about 2 to 6. When the pH is lower than 2, a cost for making the subsequent process equipment acid-resistant is required. On the other hand, if the pH is higher than 6, nickel leached in the leaching solution (slurry) may remain as a residue in the washing process (precipitate) and the washing efficiency may be reduced. In the actual operation, it is appropriate depending on conditions such as the operation status of the leaching process in the leaching step S1 and the pH of the washing water used in the solid-liquid separation step S3 (about 5 if it is acid rain) in the pH range described above. A set value may be selected.

The pH adjustment method is not particularly limited, but can be adjusted to a predetermined range by adding a neutralizing agent such as calcium carbonate slurry.

(2-2) Pre-neutralization facility In the hydrometallurgical plant 10 according to the present embodiment, the pre-neutralization facility 12 performs the pre-neutralization process in the pre-neutralization step S2.

Specifically, the preliminary neutralization equipment 12 in the hydrometallurgical plant 10 includes two stages of neutralization treatment tanks 12A and 12B as shown in FIG. Of the two- stage neutralization tanks 12A and 12B, the first-stage neutralization tank 12A _(n) corresponds to each series of the leaching tank 11 _(n) provided in the leaching equipment 11 described above. A plurality (n) series are provided to correspond. Further, the second stage neutralization treatment tank 12B is composed of a single series, and the leached slurry discharged from each of the first stage neutralization treatment tanks 12A _(n) is the second stage neutralization treatment. It is comprised so that it may join the tank 12B.

For example, when the leaching equipment 11 includes two series of leaching treatment tanks (leaching treatment tank 11 ₍₁₎ and leaching treatment tank 11 ₍₂₎ ), the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ Correspondingly, a neutralization tank 12A ₍₁₎ and a neutralization tank 12A ₍₂₎ are provided as the first-stage neutralization tank 12A. The second stage neutralization treatment tank 12B is composed of a single series of treatment tanks, and the neutralization treatment tank 12A ₍₁₎ and the neutralization treatment tank 12A ₍₂₎ constituting the first stage. The leaching slurries discharged from each of the first and second wastewaters are joined to the second neutralization treatment tank 12B.

Here, in normal operation, the slurry after pre-neutralization obtained by pre-neutralizing the leaching slurry with a plurality of series of neutralization treatment tanks is likely to vary in terms of pH, for example. The leaching slurry obtained from the neutralization tank is not uniform. When such a leaching slurry having a non-uniform property between the respective series is used and the process in the subsequent steps is performed, the reaction varies and the like, and the efficient operation cannot be performed.

Therefore, in the present embodiment, as described above, the preliminary neutralization facility 12 is provided with the two-stage neutralization treatment tanks 12A and 12B, and the upper process and the lower process are performed between the first stage and the second stage. Are divided into a plurality of series up to the first stage neutralization treatment tank 12A _(n) , and each series is integrated in the second stage neutralization treatment tank 12B. By comprising in this way, since a leaching slurry joins in the neutralization processing tank 12B of the 2nd step | paragraph, a dispersion | variation will be eliminated, and it transfers to the next solid-liquid separation process S3 as a uniform leaching slurry. Can be made. In addition, since the second-stage neutralization treatment tank 12B can function as a retention tank (buffer), the flow rate of the leaching slurry can be accurately adjusted and stably transferred to the solid-liquid separation step S3. it can.

Furthermore, by treating the leaching treatment tanks 11 _(n) in the leaching step S1 as a plurality of series, the amount of nickel oxide ore is increased, and the series is integrated in the preliminary neutralization step S2 (the next step) ( Merging), it is possible to merge at an early stage after the leaching process, and it is possible to reduce the number of parts of equipment constituting the plant. Thus, in the hydrometallurgical plant 10 which concerns on this Embodiment, the processing amount of nickel oxide ore can be increased effectively, reducing a number of parts and reducing equipment cost effectively.

As a specific neutralization method in the pre-neutralization facility 12, the low-pH leaching slurry obtained from the leaching treatment tanks 11 _{(n) of} each series is subjected to the first stage neutralization treatment corresponding to each series. The tank 12A _(n) is charged and the leaching slurry is neutralized by adding a neutralizing agent such as a calcium carbonate slurry. Thereafter, the leaching slurry neutralized in each series of neutralization treatment tanks 12A _(n) constituting the first stage is joined to the second stage neutralization treatment tank 12B, and leaching after preliminary neutralization. A slurry is obtained. In the second stage neutralization tank 12B, a neutralizing agent may be added to finely adjust the pH of the leaching slurry. Thereby, the leaching slurry whose pH has been adjusted can be subjected to the solid-liquid separation process more stably.

Here, the pipe connecting the neutralization tank 12A _(n) and the leaching tank 11 _(n) in the leaching equipment 11 to the first stage neutralization tank 12A _(n) in the preliminary neutralization equipment 12 21 _(n) can be connected. The pipe 21 _(n) is a pipe that connects the first-stage neutralization treatment tank 12A _(n) and the charging section of the leaching treatment tank 11 _{(n) in} the same series. This pipe 21 _(n) causes the leach slurry to be circulated (self-circulated) from the first stage neutralization tank 12A _(n) to the leaching tank 11 _(n) of the same series by the transfer pump 31. This is so-called self-circulation piping. The arrangement configuration of the pipe 21 _(n) and the self-circulating operation will be described in detail later.

Further, the first neutralization treatment tank 12A _(n) in the preliminary neutralization equipment 12 includes the neutralization treatment tank 12A _(n) and the final neutralization equipment 14 in the final neutralization step (detoxification step) S7. Can be connected to each other. This pipe 22 is connected to the charging section of the final neutralization equipment 14 independently from each series of the first stage neutralization tank 12A _(n) or integrated at a predetermined location from each series. The leaching slurry discharged from the first-stage neutralization tank 12A _(n) can be transferred to the final neutralization facility 14 by the transfer pump 31 provided in the pipe 22. In addition, the arrangement configuration of the piping 22 and the operation of transferring the leaching slurry from the first-stage neutralization treatment tank 12A _(n) to the final neutralization facility 14 will be described in detail later.

Further, in the first stage of the neutralization tank _12A in the pre-neutralization equipment 12 _(n), provided in multiple stages in the solid-liquid separation equipment 13 in the neutralization tank _{12A (n)} and the solid-liquid separation process S3 Moreover, the piping 23 which connects each solid-liquid separation tank can be connected. This pipe 23 is provided for each of the solid-liquid separation tanks provided in multiple stages independently from each series of the first stage neutralization treatment tank 12A _(n) or integrated at a predetermined location from each series. The leaching slurry discharged from the first stage neutralization tank 12A _(n) is transferred to a predetermined solid-liquid separation tank by a transfer pump 31 provided in the pipe 23 and connected to the charging section. Make it possible. In addition, the arrangement configuration of the piping 23 and the operation of transferring the leaching slurry from the first-stage neutralization treatment tank 12A _(n) to the predetermined solid-liquid separation tank will be described in detail later.

In addition, in FIG. 1, although the piping 21, 22, 23 mentioned above are made into common piping in part, and the transfer pump for transferring the leaching slurry is shown in common, it is limited to this. is not. Each of the pipes 21, 22, and 23 may be provided individually and a transfer pump may be installed in each of the pipes 21, 22, and 23.

(3) Solid-liquid separation step (3-1) Solid-liquid separation treatment In the solid-liquid separation step S3, nickel and cobalt were washed while washing the leached slurry after pH adjustment obtained in the preliminary neutralization step S2 in multiple stages. In addition, a leaching solution (crude nickel sulfate aqueous solution) containing zinc as an impurity element is separated from a leaching residue.

In the solid-liquid separation step S3, for example, after the leaching slurry is mixed with the cleaning liquid, the solid-liquid separation process is performed by the solid-liquid separation equipment such as a thickener using the flocculant supplied from the flocculant supply equipment. Specifically, the leaching slurry is first diluted with a cleaning liquid, and then the leaching residue in the slurry is concentrated as a thickener sediment. Thereby, the nickel content adhering to the leaching residue can be reduced according to the degree of dilution.

In this solid-liquid separation step S3, it is preferable to perform solid-liquid separation while using multiple stages of solid-liquid separation tanks such as thickeners and washing the leach slurry in multiple stages. Specifically, as the multi-stage cleaning method, for example, a continuous countercurrent cleaning method (CCD method: Counter-Current Decantation) in which a cleaning liquid is brought into contact with the leaching slurry in countercurrent can be used. Thereby, the cleaning liquid newly introduced into the system can be reduced, and the recovery rate of nickel and cobalt can be improved to 95% or more.

The cleaning liquid (cleaning water) is not particularly limited, but it is preferable to use a liquid that does not include nickel and does not affect the process. Among them, it is preferable to use an aqueous solution having a pH of 1 to 3. When the pH of the cleaning liquid is high, a bulky aluminum hydroxide is produced when aluminum is contained in the leachate, which causes poor settling of the leach residue. For this reason, as the cleaning liquid, it is preferable to repeatedly use a low pH (pH of about 1 to 3) poor liquid obtained in the nickel recovery step S6 as a subsequent step.

The flocculant to be used is not particularly limited, and for example, an anionic flocculant can be used.

(3-2) Solid-liquid separation facility In the hydrometallurgical plant 10 according to the present embodiment, the solid-liquid separation facility 13 performs the solid-liquid separation process in the solid-liquid separation step S3 described above.

Specifically, the solid-liquid separation facility 13 in the hydrometallurgical plant 10 is configured by connecting, for example, six-stage thickeners (solid-liquid separation tanks) (CCD1 to CCD6) as shown in FIG. In this solid-liquid separation facility 13, the leaching slurry after the pre-neutralization in the pre-neutralization step S2 (pH adjusted) is transferred by a transfer pump and charged into the first stage thickener (CCD 1). On the other hand, the cleaning liquid (cleaning water) is charged into the sixth-stage thickener (CCD 6) at the final stage via a pipe (not shown).

In this solid-liquid separation equipment 13, in the process in which the leach slurry charged in the CCD 1 is transferred from the CCD 1 to the CCD 2, CCD 3,. The agglomeration of the residue in the leaching slurry is repeated, and the leaching solution adhering to the residue is washed away. By this operation, the residue containing almost no leachate containing valuable metals such as nickel is discharged from the final stage CCD 6. Specifically, the nickel concentration in the moisture adhering to the residue is approximately 0 g / L, and the residue cleaned to a maximum of about 0.5 g / L is discharged. The discharged residue is transferred to the final neutralization step S7 and detoxified.

On the other hand, the cleaning liquid charged in the CCD 6 at the final stage takes in the moisture adhering to the residue in the leaching slurry in the process of being transferred from the CCD 6 to the CCD 5, CCD 4,. As a result, the concentration of valuable metals such as nickel in the cleaning liquid increases, and is finally discharged from the CCD 1 as a leachate and transferred to the neutralization step S4 of the next step. Specifically, the concentration of valuable metals in the cleaning liquid charged in the CCD 6 is, for example, approximately 0 g / L at the time of charging when the nickel concentration is 0.5 g in the transfer process from the CCD 6 to the CCD 5. In the process of transfer from the CCD 5 to the CCD 4, it gradually rises to about 1 g / L, and finally the leachate discharged from the CCD 1 has a nickel concentration of about 3 g / L.

In the above example, an example in which six stages of solid-liquid separation tanks such as thickeners are connected is shown, but the number of connected stages is not limited to this, and the installation space in the hydrometallurgical plant, It can be set as appropriate in consideration of product specifications, processing capacity in subsequent processes, and the like. Further, it is preferable that the desired concentration of the valuable metal in the leachate to be recovered is appropriately set in the same manner. Further, the nickel concentration in the liquid phase of each thickener (CCD) constituting the solid-liquid separation facility 13 is not limited to the above-described concentration.

Here, as described above, in each charging portion of the solid-liquid separation tank such as thickener provided in multiple stages, the first-stage neutralization constituting each solid-liquid separation tank and the preliminary neutralization equipment 12 is provided. A pipe 23 connecting the treatment tank 12A _(n) can be connected. This pipe 23 is provided for each of the solid-liquid separation tanks provided in multiple stages independently from each series of the first stage neutralization treatment tank 12A _(n) or integrated at a predetermined location from each series. The leaching slurry discharged from the first stage neutralization tank 12A _(n) is transferred to a predetermined solid-liquid separation tank by a transfer pump 31 provided in the pipe 23 and connected to the charging section. Make it possible. In addition, the arrangement configuration of the piping 23 and the operation of transferring the leaching slurry from the first-stage neutralization treatment tank 12A _(n) to the predetermined solid-liquid separation tank will be described in detail later.

(4) Neutralization step In the neutralization step S4, the pH of the leachate (crude nickel sulfate aqueous solution) separated in the solid-liquid separation step S3 is adjusted, and the neutralized starch containing the impurity element is separated, and nickel and A neutralized final solution containing zinc together with cobalt is obtained.

Specifically, in the neutralization step S4, the pH of the resulting neutralized final solution is 4 or less, preferably 3.0 to 3.5, more preferably 3.1 to 3, while suppressing oxidation of the separated leachate. A neutralizing agent such as calcium carbonate is added to the leachate so as to be 3.2 to form a neutralized final solution and a neutralized starch slurry containing trivalent iron as an impurity element. In the neutralization step S4, impurities such as trivalent iron ions and aluminum ions remaining in the solution are removed as neutralized starch in this way, and a neutralized final solution serving as a base for the nickel recovery mother liquor is generated. .

The neutralization process in neutralization process S4 is performed by the neutralization equipment. Examples of the neutralization facility include a neutralization reaction tank that performs a neutralization reaction, and a separation treatment tank such as a thickener that separates the neutralized starch obtained by the neutralization reaction and the neutralized final solution. This neutralization equipment consists of a single series. In the neutralization reaction tank in the neutralization facility, the leachate (crude nickel sulfate aqueous solution) discharged from the CCD 1 in the solid-liquid separation facility 13 is charged, and a neutralizing agent such as calcium carbonate is charged for neutralization. A reaction occurs. Also, in the separation treatment tank, the slurry after the neutralization reaction is charged, and the slurry is separated into a neutralized final solution that becomes a mother liquor for nickel recovery and a neutralized starch slurry that contains trivalent iron as an impurity element. To do. In this separation treatment tank, the neutralized starch slurry is extracted from the bottom of the separation treatment tank. The neutralized final solution from which the neutralized starch has been separated overflows and is stored in a storage tank or the like, and is then transferred to the next dezincing step S5.

(5) Dezincing step In the dezincing step S5, a zinc sulfide is generated by adding a sulfiding agent such as hydrogen sulfide gas to the neutralized final solution obtained from the neutralizing step S4 and subjecting it to a sulfiding treatment. The zinc sulfide is separated and removed to obtain a nickel recovery mother liquor (dezincing final solution) containing nickel and cobalt.

Specifically, for example, a neutralized final solution containing zinc and nickel and cobalt is introduced into a pressurized container, and hydrogen sulfide gas or the like is blown into the gas phase, so that zinc is made against nickel and cobalt. Selectively sulfides to produce zinc sulfide and nickel recovery mother liquor.

The dezincing process in the dezincing step S5 is performed in a dezincing facility. The dezincification equipment includes, for example, a sulfidation reaction tank that performs a sulfidation reaction by blowing hydrogen sulfide gas or the like into the final neutralized solution, and a filter device that separates and removes zinc sulfide from the solution after the sulfidation reaction. This dezincification equipment consists of a single series. In the sulfidation reaction tank in the dezincification facility, the neutralized final solution transferred through the above-described neutralization step S4 is charged, and a sulfiding agent such as hydrogen sulfide gas is blown to cause a sulfidation reaction. The filter device is constituted by a filter cloth (filter cloth) or the like, and separates zinc sulfide from the post-sulfurization reaction solution containing zinc sulfide to generate a nickel recovery mother liquor. The obtained nickel recovery mother liquor is transferred to the next nickel recovery step S6.

(6) Nickel recovery step In the nickel recovery step S6, a sulfur recovery agent such as hydrogen sulfide gas is blown into the nickel recovery mother liquor obtained by separating and removing zinc, which is an impurity element, as zinc sulfide in the zinc removal step S5. A sulfurization reaction is caused to produce a sulfide (nickel / cobalt mixed sulfide) containing nickel and cobalt and a poor solution.

The mother liquid for nickel recovery is a sulfuric acid solution in which impurity components are reduced from the leachate of nickel oxide ore through the neutralization step S4 and the dezincing step S5. The nickel recovery mother liquor may contain several g / L of iron, magnesium, manganese, etc. as impurity components. These impurity components are sulfides with respect to nickel and cobalt to be recovered. As a result, the resulting sulfide is not contained.

Nickel recovery processing in the nickel recovery step S6 is executed in a nickel recovery facility. The nickel recovery facility includes, for example, a sulfurization reaction tank that performs a sulfurization reaction by blowing hydrogen sulfide gas or the like into a nickel recovery mother liquor, and a solid-liquid separation tank that separates and recovers nickel-cobalt mixed sulfide from the liquid after the sulfurization reaction. Prepare. This nickel recovery facility consists of a single series. In the sulfidation reaction tank in the nickel recovery facility, the nickel recovery mother liquor transferred through the dezincing step S5 described above is charged, and a sulfidizing agent such as hydrogen sulfide gas is blown to cause a sulfidation reaction. Mixed sulfide is formed. Further, the solid-liquid separation tank is constituted by, for example, a thickener or the like, and is subjected to sedimentation treatment on the slurry after the sulfidation reaction containing nickel / cobalt mixed sulfide, so that nickel / cobalt mixed sulfide which is a precipitate is formed. Is recovered from the bottom of the thickener. On the other hand, the aqueous solution component overflows and is recovered as a poor solution. The recovered poor solution is a solution having a very low concentration of valuable metals such as nickel, and contains impurity elements such as iron, magnesium, and manganese remaining without being sulfided. This poor solution is transferred to the final neutralization step S7 and detoxified.

(7) Final neutralization step (7-1) Final neutralization treatment In the final neutralization step S7, the final stage of the solid-liquid separation tank provided in multiple stages in the solid-liquid separation process in the solid-liquid separation step S3 described above (for example, During the adjustment of the leaching residue discharged from the CCD 6) and the poor solution containing impurity elements such as iron, magnesium, manganese, etc. recovered in the nickel recovery step S6 to a predetermined pH range satisfying the discharge standard A summation process (detoxification process) is performed.

The pH adjustment method is not particularly limited, but can be adjusted to a predetermined range by adding a neutralizing agent such as calcium carbonate slurry.

(7-2) Final Neutral Facility In the hydrometallurgy plant 10 according to the present embodiment, the final neutralization facility 14 performs the neutralization process in the above-described final neutralization step S7.

Specifically, as the final neutralization equipment 14 in the hydrometallurgical plant 10, for example, a final neutralization treatment tank is provided in a single series. Specifically, the final neutralization facility 14 is charged with the leaching residue transferred from the solid-liquid separation step S3 and the poor solution transferred from the nickel recovery step S6. Then, in the reaction tank, the leaching residue and the poor liquid are mixed, and the pH is adjusted to a predetermined pH range by the neutralizing agent to become a waste slurry (tailing). The tailing produced | generated in this reaction tank is transferred to a tailing dam (waste storage place).

Here, as described above, the charging section of the final neutralization facility 14 includes the final neutralization facility 14 and the first-stage neutralization treatment tank 12A _(n) constituting the preliminary neutralization facility 12. The pipe 22 to be connected can be connected. This pipe 22 is connected to the charging section of the final neutralization equipment 14 independently from each series of the first stage neutralization tank 12A _(n) or integrated at a predetermined location from each series. The leaching slurry discharged from the first-stage neutralization tank 12A _(n) can be transferred to the final neutralization facility 14 by the transfer pump 31 provided in the pipe 22. The arrangement of the piping 22 and the operation of transferring the leached slurry from the first stage neutralization tank 12A _(n) to the final neutralization facility 14 will be described in detail later.

≪3. Structure of hydrometallurgical plant and method of operating hydrometallurgical plant >>
<3-1. Basic configuration and operation flow during normal operation>
<3-1-1. Basic configuration>
As described above, the hydrometallurgical plant 10 according to the present embodiment includes at least a leaching facility 11 including a plurality (n) of leaching treatment tanks 11 _(n) for performing leaching treatment on nickel oxide ore, and two stages. The neutralization treatment tanks 12A and 12B are provided, and the pre-neutralization equipment 12 for performing the pre-neutralization for adjusting the pH of the leaching slurry discharged from the leaching treatment tank 11 _(n) to a predetermined range, and a single series, It comprises a solid-liquid separation facility 13 for solid-liquid separation of the leached slurry that has been adjusted in pH and discharged from the preliminary neutralization facility 12 in a solid-liquid separation tank (FIG. 1).

As shown in FIG. 1, in the hydrometallurgical plant 10, in the preliminary neutralization facility 12, the first stage neutralization treatment tank 12 _</ b _{> A (n)} is a leaching treatment tank 11 provided in the leaching equipment 11. _A plurality of series are provided so as to correspond to each series of _(n), and the leaching slurry whose pH is adjusted in each series of neutralization treatment tanks 12A _(n) constituting the first stage consists of a single series. The second stage neutralization tank 12B is configured to join, and the leachate that has joined the second stage neutralization tank is transferred to a solid-liquid separation facility.

According to the hydrometallurgical plant 10 configured in this way, by using a plurality of series of leaching treatment facilities having a size that has been conventionally operated (for example, the amount of leachate produced is 1 to 20,000 tons / year in terms of nickel). The amount of nickel oxide ore can be increased. Further, since the subsequent processes, that is, the processes subsequent to the preliminary neutralization process, are integrated into one series, the number of parts can be reduced as a whole plant, and the equipment cost can be reduced.

In addition, according to this hydrometallurgical plant 10, each leaching slurry obtained from a plurality of series of treatment equipment (leaching treatment tank 11 _(n) , first stage neutralization treatment tank 12A _(n) ) has pH and the like. Even when there is a variation in properties, the leaching slurry discharged from each series is merged in the second stage neutralization treatment tank 12B, so that the variation can be eliminated and uniform. A solid-liquid separation process can be performed as a leach slurry.

Moreover, according to this hydrometallurgical plant 10, although mentioned later in detail, the piping 21,22 which connects the neutralization processing tank 12A _(n) of the 1st step | paragraph, and the reaction tank in the processing equipment in another process. 23 can be provided as appropriate. Thereby, for example, the leaching slurry at a stage where the leaching process such as immediately after the start of plant operation is not sufficiently progressed can be prevented from being transferred to the solid-liquid separation step S3 or a later step, Generation | occurrence | production of the reaction failure in a process, the fall of operational efficiency, etc. can be suppressed effectively.

<3-1-2. Operation flow during normal operation>
Here, the operation method at the time of normal operation of the hydrometallurgical plant 10 mentioned above is demonstrated. FIG. 3 shows a diagram for explaining the flow of operation during normal operation. Here, in the processing facility having a plurality of series, as shown in FIG. 1 and FIG. 3, two series (n = 2) of “first series (1)” and “second series (2)” are provided. Will be described as an example.

As shown by black arrows in FIG. 3, in this hydrometallurgical plant 10, for example, nickel oxide ore slurry (ore slurry) that has been crushed to a predetermined size in an ore treatment process or the like is supplied to the leaching treatment facility 11. The first series of leaching treatment tanks 11 ₍₁₎ and the second series of leaching treatment tanks 11 _(2), which are provided, are ores in the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ of each series. A leaching treatment is applied to the slurry.

Next, the leaching slurry obtained by the leaching treatment in the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ is transferred to the preliminary neutralization equipment 12. Specifically, the leaching slurry discharged from the leaching treatment tanks 11 ₍₁₎ and 11 _{(2) is} stored in the first stage corresponding to each series of the leaching treatment tanks 11 ₍₁₎ and 11 _(2). It charges to sum processing tank 12A ₍₁₎ , 12A ₍₂₎ , respectively. In each of the series of neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ , a neutralizing agent is added to the leached slurry charged to adjust the pH to a predetermined pH range.

Next, the leaching slurry whose pH has been adjusted in the first stage neutralization tanks 12A ₍₁₎ and 12A ₍₂₎ is transferred to the second stage neutralization tank 12B and charged. That is, the leaching slurry whose pH is adjusted in each of the first and second series of neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ is used as a second stage neutralization treatment tank 12B composed of a single series. To join. In this way, in the second stage neutralization treatment tank 12B, the leaching slurries from each series are merged, so that variations in properties such as pH can be eliminated, and the uniform leaching slurry is transferred to the subsequent process. can do. In the second-stage neutralization treatment tank 12B, a neutralizing agent may be added to the combined leaching slurry to finely adjust the pH.

When transferring the leach slurry to the second stage neutralization tank 12B, each of the first stage neutralization tanks 12A ₍₁₎ and 12A ₍₂₎ and the second stage neutralization tank It is transported by overflowing the leached slurry via the pipes 24 ₍₁₎ and 24 ₍₂₎ connecting to 12B.

Subsequently, the leaching slurry is discharged from the second-stage neutralization treatment tank 12B, and the leaching slurry is transferred to the solid-liquid separation facility 13. As shown in FIG. 3, for example, the solid-liquid separation facility 13 can be a facility in which six stages of thickeners (CCD1 to CCD6) are connected, and the transferred leach slurry is used as the first stage thickener (CCD1). To charge. When the leach slurry is transferred to the solid-liquid separation facility 13, the discharge section of the second-stage neutralization tank 12B and the piping 25 connecting the charging section to the first-stage thickener (CCD 1) are used. Then, transfer is performed using a transfer pump 32 provided in the pipe 25.

Thereafter, in the solid-liquid separation facility 13, the leaching slurry charged is contacted countercurrently with the cleaning liquid charged in the final stage CCD 6 in the process of transferring the leached slurry sequentially from the CCD 1 to the CCD 6. The residue in the slurry is agglomerated. Finally, a leachate (crude nickel sulfate aqueous solution) having a high concentration of valuable metals such as nickel is discharged from the CCD 1. On the other hand, the leaching residue having a low concentration of valuable metals such as nickel is discharged from the CCD 6 at the final stage, transferred to the final neutralization equipment 14 and detoxified.

<3-2. Self-circulation configuration and operation flow during self-circulation>
<3-2-1. Self-circulating configuration>
By the way, when the hydrometallurgical plant 10 is started up after periodic inspection or after stopping one or both of the two systems (at the start of operation, at start-up), the leaching process in the leaching equipment 11 is a normal (steady) operation. It takes a certain amount of time to reach the hour level. Specifically, in the leaching equipment 11, since the leaching process is performed under high temperature and high pressure, it is necessary to raise the temperature to a predetermined temperature. Therefore, in the initial stage such as immediately after the start of operation, the process of leaching valuable metals from the ore slurry has hardly started, and the leaching process is performed from the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ constituting the leaching equipment 11. Insufficient leaching slurry is discharged.

When such a leaching slurry is transferred as it is to a processing facility in which the pre-neutralization step S2 and the solid-liquid separation step S3 are performed, the concentration of valuable metals in the obtained leachate is significantly reduced, and the sulfidation reaction in the nickel recovery step S6 and the like This will cause poor reaction and decrease in operational efficiency. Such a decrease in the valuable metal concentration is particularly caused when the leaching slurry discharged in the initial stage after the start of the leaching treatment in the leaching treatment tanks 11 ₍₁₎ and 11 _(2), or when one of the series is operating normally. When the other system is started up below, the temperature rise drainage discharged from the leaching equipment 11 is the cause.

Therefore, in the hydrometallurgical plant 10 according to the present embodiment, as shown in FIG. 4, the first stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ in the preliminary neutralization facility 12, and leaching Pipes 21 ₍₁₎ and 21 ₍₂₎ connecting the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ in the facility 11 are connected. The pipes 21 ₍₁₎ and 21 ₍₂₎ are connected to the first stage neutralization tanks 12A ₍₁₎ and 12A ₍₂₎ and the charging sections of the leaching tanks 11 ₍₁₎ and 11 _(2). It is a pipe connected by the same series. That is, for example, the pipe 21 ₍₂₎ connecting the second series of leaching treatment tank 11 ₍₂₎ and the second series of neutralization treatment tank 12A ₍₂₎ .

These pipes 21 ₍₁₎ and 21 ₍₂₎ are used for the process liquid (temperature increase ₎ for raising the temperature of the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ at the time of start-up after the start of operation as described above. liquid) and leaching tank ₁₁ (1), _{11 (a} leach slurry low nickel concentration discharged from the ₂₎ leaching tank ₁₁ (1), _{11 (2)} and neutralization tank _12A (1), 12A It is possible to circulate between ₍₂₎ . In this way, the pipes 21 ₍₁₎ and 21 ₍₂₎ are the same series of leaching treatment tanks for leaching slurry and process liquid discharged from the first stage neutralization treatment tanks 12A ₍₁₎ and 12A _(2). 11 ₍₁₎ and 11 ₍₂₎ are self-circulating pipes that can be self-circulated.

As shown in FIG. 4, the pipes 21 ₍₁₎ and 21 ₍₂₎ extend from the first-stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ , respectively, and then extend to predetermined locations (see FIG. 1 and FIG. 4 may be combined at the transfer pump 31 location), branched again, and connected to the respective leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ , or completely for each series. It is good also as separate piping. In addition, a transfer pump 31 is provided in the pipes 21 ₍₁₎ and 21 ₍₂₎ , and the leaching slurry discharged from the neutralization tanks 12A ₍₁₎ and 12A ₍₂₎ is transferred to the transfer pump 31. To the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ .

Further, in the pipes 21 ₍₁₎ and 21 ₍₂₎ , for example, the transfer of the leach slurry is controlled between the neutralization tanks 12A ₍₁₎ and 12A ₍₂₎ and the transfer pump 31 described above. ON / OFF valves 42 ₍₁₎ and 42 ₍₂₎ are provided. As will be described in detail later, when the leaching slurry is self-circulated from the first stage neutralization treatment tanks 12A ₍₁₎ , 12A ₍₂₎ to the leaching treatment tanks 11 ₍₁₎ , 11 _(2). Then, the ON / OFF valves 42 ₍₁₎ and 42 ₍₂₎ are set in the ON state (“open” state) so that the discharged leached slurry can be transferred. In the normal operation described above, this for self circulation pipe ₂₁ (1), _{21 (2)} to provided the ON / OFF valve ₄₂ (1), _{42 (2)} the OFF state ( "closed" ).

<3-2-2. Operational flow during self-circulation>
Next, in the hydrometallurgical plant 10, the flow of the operation at the time of self-circulation of FIG. 4 regarding the operation method at the time of self-circulation using the above-described self- circulation pipes 21 ₍₁₎ and 21 ₍₂₎ Will be described. In addition, as shown in FIG. 4, the case where a self-circulation operation is performed in the processing equipment of the second series among the plurality of series of the first series and the second series will be described as an example. Hereinafter, similarly, an operation after starting up the second-line processing facility will be described as an example.

For example, even if the leaching process for the ore slurry is performed in the leaching treatment tank 11 ₍₂₎ in the leaching equipment 11 in the initial stage such as immediately after the start of operation, that is, immediately after the start of the operation of the _{second system} , For example, since the temperature rise of the leaching treatment tank 11 ₍₂₎ is insufficient, the obtained leaching slurry has an insufficient leaching state. Immediately after the start of the operation, in order to raise the temperature of the leaching treatment equipment 11 ₍₂₎ , a process liquid (temperature rising liquid) such as warm water is charged and the temperature rising process is performed.

Therefore, in such a stage, as shown by the flow indicated by the white arrow in FIG. 4, first, the leaching slurry or the process liquid is discharged from the leaching treatment tank 11 _(2), and the middle of the first stage of the same series. It is made to transfer to sum processing tank 12A ₍₂₎ . Thereafter, the neutralization treatment tank _{12A (2)} and the leaching tank _{11 (2)} and via a pipe _{21 (2)} connecting the leaching treatment tank 11 from the first-stage neutralization treatment tank _{12A (2) ( The} leaching slurry or process liquid is self-circulated for ₂₎ .

Specifically, in the self-circulation of the leaching slurry or process liquid, the self-circulation pipe 21 ₍₂₎ connecting the first stage neutralization treatment tank 12A ₍₂₎ and the leaching treatment tank 11 ₍₂₎ is connected. The provided ON / OFF valve 42 ₍₂₎ is turned on (“open” state). The leaching slurry or process liquid is circulated from the neutralization tank 12A ₍₂₎ to the leaching tank 11 ₍₂₎ by the transfer pump 31 provided in the self-circulation pipe 21 ₍₂₎ .

This self-circulating operation is performed, for example, until the leaching treatment tank 11 ₍₂₎ is sufficiently heated. During the self-circulation, the supply of ore slurry and the supply of sulfuric acid to the leaching treatment tank 11 ₍₂₎ are stopped. Therefore, when circulating the leaching slurry, the valuable metal concentration of the leaching slurry is substantially 0 g / L in terms of nickel.

As described above, in the hydrometallurgical plant 10 according to the present embodiment, the first stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ and the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ By providing the pipes 21 ₍₁₎ and 21 ₍₂₎ for connecting the leaching slurry and the process liquid for raising the temperature in the initial stage such as immediately after the start of operation, the self-circulation is enabled. Thereby, it is possible to prevent the leaching slurry and process liquid containing almost no nickel from being transferred to the subsequent solid-liquid separation process S3 or the like.

<3-3. Transfer configuration to final neutralization equipment and operation flow during transfer to final neutralization equipment>
<3-3-1. Transfer configuration to final neutralization equipment>
Further, even when the temperature rise of the leaching treatment tank 11 ₍₂₎ is completed and the supply of ore slurry and sulfuric acid is started by the start-up operation after the start of the operation, the leaching treatment tank 11 ₍₂₎ is still not in the leaching treatment tank 11 _(2). Sufficient leaching treatment is not performed, and a leaching slurry having a desired nickel concentration is not discharged. Such a leach slurry in which almost no nickel or the like has been leached immediately after the start of leaching cannot be transferred to the next step.

Therefore, in the hydrometallurgical plant 10 according to the present embodiment, as shown in FIG. 5, the first stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ in the preliminary neutralization facility 12 and leaching A pipe 22 connecting the leaching treatment tanks 11 ₍₁₎ , 11 ₍₂₎ and the final neutralization equipment 14 in the equipment 11 is connected. The pipe 22 is independent from each series of the first stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ , or is integrated at a predetermined location from each series, so that the final neutralization equipment 14 Connected to the charging section.

The pipe 22 is provided with a transfer pump 31, and the leach slurry discharged from the first- stage neutralization tanks 12 A ₍₁₎ and 12 A ₍₂₎ is finally neutralized by the transfer pump 31. 14 to transfer.

In addition, an ON / OFF valve 42 ₍₁₎ , which controls the transfer of the leach slurry, for example, between the neutralization tanks 12A ₍₁₎ , 12A ₍₂₎ and the above-described transfer pump is provided inside the pipe 22. 42 ₍₂₎ is provided. As will be described in detail later, when the leaching slurry is transferred from the first stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ to the final neutralization facility 14, the ON / OFF valve 42 _{( 1)} , 42 ₍₂₎ is turned on (“open” state) to allow the discharged leach slurry to be transferred. During the normal operation described above, the ON / OFF valves 42 ₍₁₎ and 42 ₍₂₎ provided in the pipe for transferring to the final neutralization facility 14 are in the OFF state (“closed” state). ing.

<3-3-2. Operation flow during transfer to final neutralization equipment>
Next, an operation method at the time of transfer to the final neutralization facility 14 using the above-described pipe 22 in the hydrometallurgical plant 10 will be described with reference to the operation flow diagram of FIG. As shown in FIG. 5, the operation of transferring the leached slurry to the final neutralization facility 14 in the second series of processing equipment of the first series and the second series will be described as an example.

For example, after the start-up operation of only the second-line processing equipment, after the temperature rise of the leaching treatment tank 11 ₍₂₎ is completed, the leaching process proceeds little by little in the leaching treatment tank 11 ₍₂₎ . However, since it is still insufficient, the nickel concentration in the discharged leaching slurry is low.

Therefore, in such a stage, as shown by the flow indicated by the white arrow in FIG. 5, first, the leaching slurry is discharged from the leaching treatment tank 11 ₍₂₎ , and the first stage neutralization treatment tank of the same series. Transfer to 12A ₍₂₎ . Then, via a pipe 22 which connects the neutralization tank _12A and ₍₂₎ and a final neutralization equipment 14, transferring the leached slurry from the neutralization tank _{12A (2)} to a final neutralization equipment 14.

Specifically, when the leaching slurry is transferred to the final neutralization equipment 14, the above-described self-circulation piping (first stage neutralization treatment tank 12A ₍₂₎ and leaching treatment tank 11 ₍₂₎ are connected. Piping) 21 The ON / OFF valve 43 provided in ₍₂₎ is turned off (“closed” state). Next, the ON / OFF valve 42 ₍₂₎ provided in the pipe 22 connecting the first-stage neutralization treatment tank 12A ₍₂₎ and the final neutralization equipment 14 is turned on ("open" state). To do. Then, the leach slurry is transferred from the neutralization tank 12A ₍₂₎ to the final neutralization facility 14 by the transfer pump 31 provided in the pipe 22.

The transfer operation of the leaching slurry to the final neutralization equipment 14 is performed, for example, by the nickel concentration of the leaching slurry discharged from the leaching treatment tank 11 ₍₂₎ among the thickeners provided in multiple stages in the solid-liquid separation equipment 13. This is performed when the nickel concentration in the liquid phase in the stage thickener (CCD 6) is lower. Note that the valuable metal concentration of the leaching slurry at this stage, that is, the stage of carrying out the transfer operation to the final neutralization facility 14 is, for example, about 0 to 5 g / L in terms of nickel.

As described above, in the hydrometallurgical plant 10 according to the present embodiment, the piping 22 that connects the first-stage neutralization treatment tanks 12A ₍₁₎ , 12A ₍₂₎ and the final neutralization equipment 14 is provided. Thus, the leaching slurry discharged at the stage where the leaching process is not sufficiently advanced at the start of operation can be transferred to the final neutralization facility 14. Thereby, it is possible to prevent the leaching slurry having a low nickel concentration from being transferred to the solid-liquid separation step S3 or the like in the subsequent step.

<3-4. Transfer configuration to solid-liquid separation tank and operation flow at the time of transfer to solid-liquid separation tank>
<3-4-1. Transfer configuration to solid-liquid separation tank>
Furthermore, the leaching process gradually proceeds after the start of operation, and the nickel concentration of the leaching slurry discharged from the leaching treatment tank 11 ₍₂₎ is more than the nickel concentration of the leachate in the final stage thickener (CCD 6) of the solid-liquid separation facility. Even if it becomes high, if the nickel concentration is still insufficient, it cannot be transferred to the next step. That is, when it is lower than the desired nickel concentration of the leaching slurry to be transferred to the second-stage neutralization tank 12B, it cannot be transferred to the next step.

Therefore, in the hydrometallurgical plant 10 according to the present embodiment, as shown in FIG. 6, the first stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ in the preliminary neutralization facility 12 are In the liquid separation equipment 13, pipes 23 that connect the respective solid-liquid separation tanks (thickeners) provided in multiple stages are connected. This pipe 23 is independent from each series of the first-stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ , or is integrated at a predetermined location from each series, so that each solid-liquid separation tank Connected to the charging section. More specifically, the pipe 23 extends from the first-stage neutralization treatment tanks 12A ₍₁₎ and 12A ₍₂₎ toward the solid-liquid separation facility 13 and has multiple stages constituting the solid-liquid separation facility 13. It branches so that it may be connected with each connected solid-liquid separation tank (CCD1, CCD2, ... CCD6).

The pipe 23 is provided with a transfer pump 31, and the leaching slurry discharged from the first- stage neutralization tanks 12 A ₍₁₎ and 12 A ₍₂₎ is solid-liquid separated by the transfer pump 31. 13 is transferred to a predetermined solid-liquid separation tank.

In addition, an ON / OFF valve 42 ₍₁₎ for controlling the transfer of the leaching slurry between the neutralization tanks 12A ₍₁₎ , 12A ₍₂₎ and the above-described transfer pump 31, for example, is provided inside the pipe 23. , 42 ₍₂₎ are provided. As will be described in detail later, when the leaching slurry is transferred from the neutralization tanks 12A ₍₁₎ and 12A ₍₂₎ to a predetermined solid-liquid separation tank in the solid-liquid separation facility 13, the ON / OFF valve is used. 42 ₍₁₎ and 42 ₍₂₎ are turned on (“open” state), and the discharged leached slurry can be transferred. In the normal operation described above, the ON / OFF valves 42 ₍₁₎ and 42 ₍₂₎ provided in the pipe 23 for transferring to a predetermined solid-liquid separation tank are in an OFF state (“closed” state). It has become.

Further, the pipe 23 is provided with an ON / OFF valve 44 for controlling the transfer of the leaching slurry at each branch point toward the solid-liquid separation tanks connected in multiple stages. Thereby, according to the nickel density | concentration in the leaching slurry to transfer, it is possible to carry out transfer control to the solid-liquid separation tank which is an appropriate transfer destination. As a method for controlling the transfer destination, a switching valve for switching the transfer destination may be provided at a predetermined branch point, and switching control of the switching valve may be performed.

<3-4-2. Operation flow during transfer to solid-liquid separation tank>
Next, in the hydrometallurgical plant 10, about the operation method at the time of the transfer to the solid-liquid separation tank which comprises the solid-liquid separation equipment 13 using the piping 23 mentioned above, the figure which shows the flow of operation of FIG. 6 is used. I will explain. As shown in FIG. 6, in the second series of processing equipment of the first series and the second series, the leach slurry is used as the second-stage solid-liquid separation tank (CCD 2) in the solid-liquid separation equipment 13. ) Will be described as an example.

For example, even in a situation where the leaching process is gradually progressing after the start-up operation of the second series of processing equipment, if the leaching process is not sufficient to the level of the normal operation, the leaching process tank 11 _{( Since} the nickel concentration of the leaching slurry discharged from ₂₎ is low, it cannot be transferred to the next step. Specifically, for example, even when the leaching treatment proceeds and the valuable metal concentration in the leaching slurry exceeds 5 g / L in terms of nickel, the leaching slurry to be transferred to the second stage neutralization treatment tank 12B. If it is lower than the desired nickel concentration, it cannot be transferred to the next step.

Therefore, in such a stage, as shown by the flow indicated by the white arrow in FIG. 6, first, the leaching slurry is discharged from the leaching treatment tank 11 ₍₂₎ , and the first stage neutralization treatment tank of the same series. Transfer to 12A ₍₂₎ . Then, via a pipe 23 for connecting the the solid-liquid separation equipment 13 neutralization treatment tank _{12A (2),} the leach slurry is transferred from the neutralization tank _{12A (2)} to solid-liquid separation equipment 13.

At this time, depending on the valuable metal concentration in the leaching slurry, it is sent to the solid-liquid separation tank corresponding to the concentration. For example, when the valuable metal concentration in the leaching slurry is 2.5 g / L in terms of nickel, the second stage where the nickel equivalent concentration in the liquid phase during normal operation (steady state) is about 2.5 g / L. It is made to transfer to the solid-liquid separation tank (CCD2) of eyes. In this way, by appropriately controlling the transfer destination according to the valuable metal concentration in the leaching slurry, it is possible to prevent the first system during normal operation from being affected, and efficient operation is possible. To.

Specifically, when the leaching slurry is transferred to the CCD 2 in the solid-liquid separation facility 13, the above-described self-circulation piping (first stage neutralization treatment tank 12A ₍₂₎ and leaching treatment tank 11 ₍₂₎ , 21 _{) The} ON / OFF valve 43 provided in ₍₂₎ is turned off (“closed” state). Further, an ON / OFF provided in a pipe 22 (a pipe connecting the first-stage neutralization treatment tank 12A ₍₂₎ and the final neutralization equipment 14) 22 for transferring the leach slurry to the final neutralization equipment 14 described above. The OFF valve 45 is turned off (“closed” state).

Next, the ON / OFF valve 42 ₍₂₎ provided in the pipe 23 connecting the first stage neutralization treatment tank 12A ₍₂₎ and the solid-liquid separation facility 13 is turned on ("open" state). To do. Then, the leaching slurry is transferred from the first-stage neutralization tank 12A ₍₂₎ to the solid-liquid separation facility 13 by the transfer pump 31 provided in the pipe 23. At this time, the ON / OFF valve 44 provided at each branch point for branching to each solid-liquid separation tank in the solid-liquid separation facility 13 is controlled so that the leached slurry is transferred to the CCD 2. Specifically, the ON / OFF valve 44 at the branch point to the CCD 2 is turned on (“open” state), and the ON / OFF valves 44 at the other branch points to the CCD 1 and CCD 3 to CCD 6 are turned off (“ Closed state).

As described above, in the hydrometallurgical plant 10 according to the present embodiment, the piping 23 that connects the first- stage neutralization tanks 12A ₍₁₎ and 12A ₍₂₎ and the solid-liquid separation facility 13 is provided. Thus, the leaching process after the start of operation is not yet sufficient and the leaching slurry having a low nickel concentration can be transferred to a predetermined solid-liquid separation tank. This prevents the leaching slurry with a low nickel concentration from being mixed with the leaching slurry discharged from the series that is normally operating, and prevents reaction failures and deterioration of operation efficiency in the subsequent process. Can do.

<3-5. Transition from non-normal operation to normal operation>
Then, when a predetermined time has elapsed from the start of operation and the operation conditions such as the concentration of valuable metals in the leaching slurry discharged from the leaching treatment tank 11 ₍₂₎ and the flow rate of the liquid return to the normal operation level, Each non-normal operation route is closed, and normal operation is performed on the normal operation route.

That is, after transferring the leach slurry discharged from the leaching vessel _{11 (2)} to the first stage of the neutralization tank _{12A (2),} first stage neutralization tank _12A and ₍₂₎ second Through the pipe 24 ₍₂₎ connecting the stage neutralization tank 12B, the leaching slurry is allowed to overflow into the second stage neutralization tank 12B. Then, the leaching slurry is transferred from the second-stage neutralization tank 12B to the CCD 1 in the solid-liquid separation facility 13 to perform the solid-liquid separation process.

<3-6. Summary>
As described above, according to the hydrometallurgical plant 10 according to the present embodiment, the amount of nickel oxide ore is increased and the production amount of nickel / cobalt mixed sulfide is improved while reducing the equipment cost. Can do. Further, even if the leaching slurries obtained from a plurality of series of treatment facilities have variations in properties such as pH, the leaching slurries discharged from the respective series are merged in the second stage neutralization treatment tank 12B. Therefore, the variation can be eliminated, and the solid-liquid separation process can be performed as a uniform leaching slurry.

Moreover, in this hydrometallurgical plant 10, by providing the pipes 21, 22, and 23 as described above, the leaching slurry having a low nickel concentration is transferred to a subsequent process at an abnormal time such as when the processing equipment is started up. This can be prevented. Thereby, the reaction failure in a post process and the fall of operational efficiency can be suppressed.

And in this hydrometallurgical plant 10, the first-stage neutralization tank 12A ₍₁ ) of the pre-neutralization equipment 12 in which the pipes 21, 22, and 23 described above are constituted by two-stage neutralization tanks. ₎ , 12A ₍₂₎ . For this reason, there is no influence on the operation in one of the lines where the normal operation is continued. That is, as shown in the examples of FIGS. 4 to 6, in the second series during the start-up operation, the leaching slurry is self-circulated or transferred to the final neutralization facility 14 or the solid-liquid separation facility 13 while In the first series, it is possible to perform a normal operation as shown by a black arrow. In this way, in the hydrometallurgical plant 10, a two-stage neutralization tank is provided, and only one first-stage neutralization tank is provided as a plurality of lines, so that one of the lines is not affected. The start-up operation at the start of operation (non-normal operation) can be performed.

It should be noted that when the non-normal operation is performed in one of the series (for example, the second series), it is transferred to the second stage neutralization treatment tank 12B as compared to the case where both the series are operated normally. The amount of leaching slurry is reduced. Therefore, the operation is continued by reducing the capacity of the pump for normal operation and the processing capacity in the subsequent process to the extent appropriate for the amount of liquid. However, as described above, in the other series (for example, the first series), normal operation is possible without stopping the operation, so there is no influence on the quality of the product.

1 and FIGS. 3 to 6 show a configuration in which some of the pipes 21, 22, and 23 used in the non-normal operation are shared pipes. Moreover, the transfer pump 31 for transferring the leaching slurry through the pipes 21, 22, 23 is also common. However, the present invention is not limited to this, and it goes without saying that the pipes 21, 22, and 23 may be provided completely individually, and a transfer pump may be provided for each of them. Moreover, in this hydrometallurgical plant 10, what is necessary is just to determine the installation method of piping suitably in consideration of a transfer route. In addition, it is preferable because the number of equipment and the cost can be reduced by sharing the sharable parts in the piping.

1 and FIGS. 3 to 6 show an embodiment in which all of the pipes 21, 22, and 23 used in the non-normal operation are shown, but one or two pipes are provided. May be.

<< 4. Examples >>
Next, examples to which the present invention is applied will be described, but the present invention is not limited to the following examples.

<Operation of wet smelting plant>
(Operation example 1)
In a nickel oxide ore hydrometallurgical plant, each treatment facility was configured as shown in FIG. 1 and a 30-day hydrometallurgical operation was carried out.

That is, a leaching facility 11 having two series of leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ and a two-stage neutralization treatment tank are provided, and the first-stage neutralization treatment tanks 12A ₍₁₎ and 12A _{( The} operation is performed by the hydrometallurgical plant 10 including the pre-neutralization facility 12 in which ₂₎ corresponds to the leaching treatment tank and the second stage neutralization treatment tank 12B is a single series. It was. In the solid-liquid separation equipment 13, as shown in FIG. 1, six stages of thickeners (CCD1 to CCD6) are connected to perform multi-stage cleaning.

As a result, no leaching failure occurred in the leaching equipment subjected to high pressure acid leaching during the 30-day period, and the operation did not stop in any of the two systems. Further, the production amount of the nickel / cobalt mixed sulfide obtained in this operation was 2500 tons in terms of nickel, and there was no problem in the product quality.

The set values of valuable metals in the liquid phase of the CCD of each stage in the solid-liquid separation equipment 13 are nickel equivalent concentrations, CCD1: 3 g / L, CCD 2: 2.5 g / L, CCD 3: 2 g / L, CCD 4: 1.5 g / L, CCD 5: 1 g / L, CCD 6: 0.5 g / L or less.

(Operation example 2)
Using a plant similar to the wet smelting plant 10 used in Operation Example 1, a 30 day wet smelting operation was carried out. The set value of the valuable metal in the liquid phase of the CCD of each stage in the solid-liquid separation equipment 13 was set to be the same as in Operation Example 1.

In the operation of this operation example 2, during the operation period, there were five stoppages due to equipment troubles in the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ in the first line or the second line. For this reason, we stopped and started up the line where the equipment trouble occurred, 5 times. At this time, in the start-up operation, as shown in FIGS. 4 to 6, the operation is performed in an abnormal state according to the nickel concentration of the leaching slurry discharged from the leaching treatment tanks 11 ₍₁₎ and 11 _(2). To do. In such start-up operation, the average required time from stop to return was one day.

As a result of operation for 30 days, the amount of nickel-cobalt mixed sulfide produced was 2075 tons (about 83% of Operation Example 1), and there was no problem in product quality.

(Operation example 3)
Using a plant similar to the wet smelting plant 10 used in Operation Example 1, a 30 day wet smelting operation was carried out. The set value of the valuable metal in the liquid phase of the CCD of each stage in the solid-liquid separation equipment 13 was set to be the same as in Operation Example 1.

Also in this operation example 3, like the operation example 2, during the operation period, the leaching failure occurred in the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ in the first series or the second series five times. For this reason, the series where the leaching failure occurred was stopped and started up five times. At this time, in Operation Example 3, the entire hydrometallurgical plant 10 was stopped. In such start-up operation, the average time from stop to return was 2 days.

As a result of the operation for 30 days, there was no problem in the product quality of the obtained nickel-cobalt mixed sulfide, but its production amount was very small as 1300 tons (about 52% of Operation Example 1) Could not produce quantity.

In theoretical simple calculation, although the production volume of about 67% of the operation example 1 can be expected, the reason for having become 1300 tons is to stop the entire hydrometallurgical plant 10 when leaching failure occurs. It is thought that it depends on doing so. That is, because the entire plant is stopped, for example, it is necessary to stop and restart the operation in the dezincing step S5, the nickel recovery step S6, etc., and the timing of starting the operation of each processing facility in the plant is adjusted. It is thought that extra stop time was required.

(Operation example 4)
Using a plant similar to the wet smelting plant 10 used in Operation Example 1, a 30 day wet smelting operation was carried out.

Also in this operation example 4, like the operation example 2, during the operation period, the leaching failure occurred in the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ in the first series or the second series five times. For this reason, the series where the leaching failure occurred was stopped and started up five times. At this time, in the operation example 4, the leaching slurry discharged from the leaching treatment tanks 11 ₍₁₎ and 11 _{(2) being} started up, that is, the leaching slurry having a low nickel concentration due to insufficient leaching treatment is used as it is. It was made to transfer to the neutralization processing tank 12B of the 2nd step via the neutralization processing tank 12A ₍₁₎ , 12A ₍₂₎ of the step. In such start-up operation, the average time from stop to return was 2 days.

As a result of the operation for 30 days, the production amount of the obtained nickel-cobalt mixed sulfide was 2250 tons (about 90% of the operation example 1), but the product quality deteriorated. Specifically, the ratio of valuable metals in the nickel / cobalt mixed sulfide decreased, and it became a defective product that could not be shipped as a product, which had to be disposed of.

This is considered to be due to the fact that in the start-up operation (non-normal operation), the leaching slurry obtained at the stage where the leaching treatment is insufficient is transferred to the subsequent process as it is. That is, the leaching slurry having a low nickel concentration is transferred to a subsequent process and subjected to solid-liquid separation, and the sulfidation treatment in the nickel recovery step S6 is performed by the obtained low nickel concentration leaching solution. As a result, product quality is thought to have deteriorated.

In addition, although the setting value of the valuable metal in the liquid phase of the CCD of each stage in the solid-liquid separation facility 13 was set to be the same as that of the operation example 1, the low-concentration leaching slurry was often accepted, so the solid-liquid separation The fluctuation range of concentration in the tank (CCD) was increased, and stable operation could not be performed.

<Changes in nickel concentration in overflow liquid>
Next, in the case where the leaching treatment tanks 11 ₍₁₎ and 11 ₍₂₎ in the leaching step S1 of the single series (first series or second series) were stopped due to equipment trouble, and the startup operation was performed thereafter, The transition of the nickel concentration in the overflow liquid in the first-stage solid-liquid separation tank (CCD 1) in the operation examples 5 and 6 was examined.

(Operation example 5)
In the operation example 5, as in the operation example 2 described above, only the stopped line is circulated to the leaching treatment tank at the time of temperature rise in the system, and then acid leaching is started until the nickel concentration reaches a prescribed concentration. In accordance with the nickel concentration, operation was performed to send the solution to the final neutralization facility 14 (final neutralization step S7) or the solid-liquid separation tank having an appropriate nickel concentration (FIGS. 4 to 6).

Table 1 below shows the transition of the nickel concentration (g / L) in the overflow from the first-stage solid-liquid separation tank (CCD1) when operated as described above. As shown in Table 1, it can be seen that in this operation example 5, the nickel concentration is extremely stable from the start of operation. In the sulfidation reaction in the subsequent sulfidation process using this overflow liquid as a treatment target, the reaction occurred stably without causing a reaction failure or the like.

(Operation example 6)
In the operation example 6, as in the operation example 4 described above, all of the liquids at the time of the temperature increase in the stopped series and the leachate in which the nickel concentration immediately after the start of the acid leaching does not reach the specified concentration are continuously operated. In the same manner as described above, the sample was transferred to the second stage pre-neutralization tank 12B.

Table 1 below shows the transition of the nickel concentration (g / L) in the overflow from the first-stage solid-liquid separation tank (CCD1) when operated as described above. As shown in Table 1, it can be seen that the nickel concentration decreased extremely over about half a day from the start of operation. As a result, in the subsequent sulfidation step, due to the extremely low nickel concentration, adjustment of the sulfidation reaction becomes very difficult, resulting in poor sulfidation reaction and excessive sulfidation reaction.

　　

Claims (11)

1. at least,
   A leaching facility comprising a plurality of leaching treatment tanks for leaching the nickel oxide ore;
   A pre-neutralization facility comprising a two-stage neutralization tank, and performing pre-neutralization to adjust the pH of the leaching slurry discharged from the leaching tank to a predetermined range;
   Comprising a single series, a solid-liquid separation facility for solid-liquid separation of the leaching slurry adjusted in pH and discharged from the pre-neutralization facility into a leaching solution and a leaching residue in a solid-liquid separation tank,
   In the preliminary neutralization equipment, the first stage neutralization treatment tank is provided with a plurality of series so as to correspond to each series of the leaching treatment tank provided in the leaching equipment, and each of the first stage constituting the first stage A leaching slurry whose pH is adjusted in a series of neutralization tanks is configured to merge with a second stage neutralization tank consisting of a single series, and the second stage neutralization tank A nickel oxide ore hydrometallurgical plant characterized in that the leaching slurry that joins the slag is transferred to the solid-liquid separation facility.
2. A pipe for connecting the first stage neutralization treatment tank and the charging section of the leaching treatment tank in the leaching equipment in the same series is provided,
   The nickel oxidation according to claim 1, wherein the leaching slurry or the process liquid discharged from the first stage neutralization treatment tank can be circulated to the same series of leaching treatment tanks in the leaching equipment. Ore hydrometallurgical plant.
3. A final neutralization facility for performing a neutralization treatment on the leach residue obtained by solid-liquid separation in the solid-liquid separation facility, and the first-stage neutralization tank and the final neutralization facility Piping connecting the charging section is provided,
   2. The nickel oxide ore hydrometallurgical plant according to claim 1, wherein the leaching slurry discharged from the first stage neutralization treatment tank can be transferred to the final neutralization facility.
4. 2. The nickel oxide ore according to claim 1, wherein the solid-liquid separation facility is provided with multi-stage solid-liquid separation tanks and separates the leached slurry discharged from the neutralization tank while performing multi-stage washing. Wet smelting plant.
5. A pipe is provided to connect the first-stage neutralization tank and the charging section of each solid-liquid separation tank provided in multiple stages in the solid-liquid separation facility,
   5. The nickel oxide ore hydrometallurgical plant according to claim 4, wherein the leaching slurry discharged from the first stage neutralization treatment tank can be transferred to each of the solid-liquid separation tanks.
6. 2. The nickel oxide ore hydrometallurgical plant according to claim 1, wherein the amount of leaching slurry in the leaching equipment is 1 million tons / year to 2 million tons / year in terms of nickel amount. .
7. A method of operating a hydrometallurgical plant for recovering nickel and cobalt from nickel oxide ore,
   The nickel oxide ore hydrometallurgical plant is at least:
   A leaching facility comprising a plurality of leaching treatment tanks for leaching the nickel oxide ore;
   A pre-neutralization facility comprising a two-stage neutralization tank, and performing pre-neutralization to adjust the pH of the leaching slurry discharged from the leaching tank to a predetermined range;
   Comprising a single series, a solid-liquid separation facility for solid-liquid separation of the leaching slurry adjusted in pH and discharged from the pre-neutralization facility into a leaching solution and a leaching residue in a solid-liquid separation tank,
   In the preliminary neutralization facility, the first stage neutralization tank is provided with a plurality of series corresponding to each series of the leaching tanks provided in the leaching equipment, and the second stage neutralization tank. Consists of a single series,
   The leaching slurry discharged from each neutralization treatment tank in the first stage is merged with the second stage neutralization treatment tank consisting of a single series, and the merged leaching slurry is transferred to the solid-liquid separation facility. A method for operating a nickel oxide ore hydrometallurgical smelting plant.
8. A pipe for connecting the first stage neutralization treatment tank and the charging section of the leaching treatment tank in the leaching equipment in the same series is provided,
   In the stage immediately after the start of operation, the leaching slurry or process liquid discharged from the leaching treatment tank is circulated from the first stage neutralization treatment tank to the leaching treatment tank via the pipe. A method for operating a nickel oxide ore hydrometallurgical plant according to claim 7.
9. 8. The nickel oxide ore according to claim 7, wherein the solid-liquid separation facility is provided with multi-stage solid-liquid separation tanks and performs solid-liquid separation while washing the leachate discharged from the neutralization tank multi-stage. To operate a wet smelting plant.
10. A final neutralization facility for performing a neutralization treatment on the leach residue obtained by solid-liquid separation in the solid-liquid separation facility, and the first-stage neutralization tank and the final neutralization facility Piping connecting the charging section is provided,
    When the nickel concentration of the leaching slurry discharged from the leaching treatment tank is lower than the nickel concentration of the leaching liquid in the solid-liquid separation tank at the final stage of the solid-liquid separation facility, the leaching slurry discharged from the leaching treatment tank 10. The method for operating a nickel oxide ore hydrometallurgical plant according to claim 9, wherein the first-stage neutralization treatment tank is transferred to the final neutralization equipment via the pipe.
11. A pipe is provided to connect the first-stage neutralization tank and the charging section of each solid-liquid separation tank provided in multiple stages in the solid-liquid separation facility,
    When the nickel concentration of the leaching slurry discharged from the leaching treatment tank is lower than the desired nickel concentration of the leaching liquid to be transferred to the second stage neutralization treatment tank, the leaching discharged from the leaching treatment tank The operation of the nickel oxide ore hydrometallurgical plant according to claim 9, wherein the slurry is transferred from the first-stage neutralization tank to the solid-liquid separation tank of a predetermined stage via the pipe. Method.

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