JP6565511B2 - Ore slurry processing method, nickel oxide ore hydrometallurgy method - Google Patents

Description

  The present invention relates to an ore slurry treatment method and a nickel oxide ore hydrometallurgy method, and more specifically, in a hydrometallurgical method of leaching and recovering nickel and cobalt from nickel oxide ore by acid leaching. The present invention relates to a method for treating ore slurry supplied to leaching treatment and a method for hydrometallizing nickel oxide ore including the treatment step.

  In recent years, as the mining rights have become more and more oligopolistic in mineral resources such as iron, copper, nickel, cobalt, chromium and manganese, the raw material costs in metal smelting have increased significantly. In order to cope with this large increase in cost, technology development for using low-grade ore that has not been the object of smelting has been conducted.

  For example, in nickel smelting, a material excellent in corrosion resistance under high temperature and high pressure has been developed, and wet based on a high pressure acid leaching (HPAL) method of acid leaching nickel oxide ore under pressure with sulfuric acid. Smelting methods are attracting attention.

  This high-pressure acid leaching method is advantageous in terms of energy cost because it does not have a dry process such as a reduction process or a drying process, unlike a dry smelting process that is a conventional smelting method of nickel oxide ore. In the future, it will continue to be an effective technique for smelting low-grade nickel oxide ore (hereinafter simply referred to as “ore”).

  Moreover, in order to raise the completeness as a smelting process of the hydrometallurgical process based on this high pressure acid leaching method, focusing on the leaching process under high temperature and pressure, improvement of the leaching rate of nickel and cobalt, purification of the leachate Various proposals have been made regarding reductions in the amount of operating materials used.

By the way, as a process for performing a leaching treatment under high temperature and pressure, Patent Document 1 discloses a method comprising the following steps (a) to (c) from ores containing valuable metals such as nickel, cobalt, and manganese. A method for recovering valuable metals is disclosed.
Step (a): Slurry ore is leached at atmospheric pressure under acidic conditions using sulfuric acid acid obtained in step (b) to obtain atmospheric leaching solution and atmospheric leaching residue.
Step (b): The atmospheric pressure leaching residue obtained in step (a) is reacted with sulfuric acid in an oxidizing atmosphere under high temperature and pressure to obtain a pressurized acid leaching solution.
Step (c): A neutralizing agent is added to the atmospheric leachate obtained in step (a) to neutralize it, and then an alkali sulfide compound is added to recover nickel and cobalt in the leachate as sulfides.

  In this method, the nickel leaching rate from the ore is improved by performing two-stage leaching in which the ore slurry is leached at atmospheric pressure in step (a) and then the pressure leaching residue is leached under pressure in step (b). At the same time, excess acid contained in the leaching solution of the pressurized acid leaching is neutralized by the alkali component contained in the atmospheric leaching residue, thereby reducing the load of the neutralization step (step (c)).

  However, since this is a two-stage leaching process, there are problems such as an increase in the number of equipment and cost and labor, and a problem in that a large amount of thin liquid generated when cleaning leaching residues is costly. .

In order to solve these problems, Patent Document 2 discloses a method including the following steps (i) to (iv) as another process using leaching under high temperature and pressure.
(I) Leaching step: ore is slurried and sulfuric acid is added and stirred at a temperature of 220 to 280 ° C. to form a leaching slurry.
(Ii) Solid-liquid separation step: The leaching slurry is washed using a multi-stage thickener and separated into a leaching solution containing nickel and cobalt and a leaching residue.
(Iii) Neutralization step: Adjusting the pH to be 4 or less using calcium carbonate while suppressing oxidation of the leachate to produce a neutralized starch containing trivalent iron, and neutralized starch slurry And nickel recovery mother liquor.
(Iv) Sulfurization step: Hydrogen sulfide gas is blown into the mother liquor for nickel recovery to produce a sulfide containing nickel and cobalt, which is separated into a sulfide containing nickel and cobalt and a poor solution.

  Here, the outline | summary of the practical plant based on the technique disclosed by patent document 2 is demonstrated using FIG. In addition, FIG. 1 is a smelting process figure in an example of the practical plant based on the hydrometallurgy method of nickel oxide ore.

  As shown in the process diagram of FIG. 1, first, in [1] ore processing step, nickel oxide ore as a raw material is mixed with water, foreign matters are removed from the obtained mixture, and ore particle size is adjusted. This is done to form an ore slurry of nickel oxide ore.

  Next, in the [2] leaching step, the obtained ore slurry is subjected to high temperature pressure leaching using sulfuric acid to form a leaching slurry containing a leaching solution and a leaching residue.

  Next, in the [3] solid-liquid separation step, the obtained leaching slurry is subjected to multistage cleaning, and then separated into a leaching solution containing nickel and cobalt and a leaching residue slurry.

  Next, in the [4] neutralization step, the separated leachate is neutralized and separated into a neutralized starch slurry containing trivalent iron hydroxide and a post-neutralized solution.

  Next, in the [5] zinc removal step, a sulfurizing agent is added to the post-neutralization solution, the zinc contained in the solution becomes a sulfide, and the zinc sulfide starch containing zinc sulfide and the zinc are removed. Separated into mother liquor for nickel recovery.

  Next, [6] In the sulfiding step, a sulfiding agent is added to the mother liquor for recovering nickel, and nickel and cobalt contained in the mother liquor become sulfides, and mixed sulfides of nickel and cobalt, nickel, etc. Separated from the removed poor solution. The poor liquid is used as washing water for the leach residue in the solid-liquid separation step [3].

  Finally, in [7] final neutralization step, the excess poor liquid and the leaching residue slurry separated in the solid-liquid separation step [3] are neutralized, and the final produced by the neutralization treatment Neutralization residue is stored in the tailing dam.

  As a feature of such a smelting process, the leaching slurry is washed in multiple steps in the solid-liquid separation step [3], thereby reducing the consumption of neutralizing agent and the amount of starch in the neutralization step [4] of the next step. It can be reduced, and since the true density of the leach residue can be increased, the solid-liquid separation characteristics can be improved. Further, there is a feature that the process can be simplified by performing the leaching process in the leaching step [2] only by high-temperature pressure leaching, which is advantageous over the method disclosed in Patent Document 1. It is said that.

  Furthermore, by using the poor solution generated in the sulfidation step [6] as the cleaning solution used in the solid-liquid separation step [3], the nickel adhering to the leaching residue is leached using sulfuric acid remaining in the poor solution. It is said that effective and efficient water can be used repeatedly. Furthermore, the loss of nickel can be reduced by returning the slurry of the neutralized starch produced in the neutralization step [4] to the solid-liquid separation step [3], which is more advantageous. .

  However, this smelting process has the following problems.

  First, there is suppression of equipment wear. Nickel oxide ore is transported between facilities in each process as ore slurry, but the equipment material is significantly worn by the ore slurry at the time of transport, especially repair pipes and pumps in the leaching process are frequently repaired, This is a major cause of an increase in maintenance costs and a decrease in plant availability.

  Secondly, there is a reduction in the amount of final neutralization residue. The leaching residue slurry produced in the solid-liquid separation step [3] is combined with the excess poor liquid produced from the sulfidation step [6], and neutralized using limestone slurry or slaked lime slurry in the final neutralization step [7]. Processed and detoxified. The final neutralization residue produced from this final neutralization step [7] is stored in a tailing dam. This final neutralization residue includes impurities such as hematite and chromite in the leach residue slurry. Since gypsum formed by the neutralization treatment is contained, it cannot be recycled, and a large cost burden for the construction and maintenance of the tailing dam has occurred.

  Thus, in the practical plant using the hydrometallurgical method based on the conventional high pressure acid leaching method, the solution of the subject mentioned above is calculated | required. Furthermore, in order to solve the problem effectively and economically, it becomes an effective means to efficiently separate and recover the impurity components contained in the ore or the leach residue slurry, and these impurity components can be recycled as resources. Effective utilization is also required.

  In Patent Document 3, in hydrometallurgy based on the high pressure acid leaching method, a step of physically separating and recovering particles containing at least one selected from silica mineral, chromite, or siliceous clay from ore slurry, and leaching residue A method of hydrometallizing nickel oxide ore including a step of physically separating and recovering hematite particles in a slurry is disclosed. However, further improvement is required for efficient separation and recovery of impurity components contained in the ore or leach residue.

JP-A-6-116660 JP-A-2005-350766 JP 2010-95788 A

  The present invention has been proposed in view of such a situation, and in a hydrometallurgical process of nickel oxide ore using acid leaching treatment, equipment such as piping and pumps using ore slurry supplied to the acid leaching treatment is provided. An object of the present invention is to provide a method capable of suppressing wear and reducing the amount of final neutralization residue produced from the final neutralization step in the hydrometallurgical process.

  As a result of intensive studies, the inventors performed classification treatment on the ore slurry to separate the mixture containing goethite from the mixture containing chromite, and then the magnetic separation process on the mixture containing chromite. By separating and removing chromite as a non-magnetized material, it is possible to reduce chromite in the ore slurry to be subjected to the acid leaching treatment, and to find out that the above-mentioned problems can be solved. It came to be completed. That is, the present invention provides the following.

  (1) 1st invention of this invention is a processing method of the ore slurry used for the acid leaching process in the hydrometallurgy method of nickel oxide ore, Comprising: The classification apparatus was used with respect to the ore slurry of the said nickel oxide ore. A classification process is performed to obtain a mixture containing goethite and a mixture containing chromite, and a mixture containing magnetite as a magnetized product is separated from the mixture containing chromite using a magnetic separator. A magnetic separation process for separating a mixture containing chromite as a non-magnetized product, a mixture containing the goethite obtained in the classification process, and a mixture containing the magnetite separated in the magnetic separation process Is an ore slurry used for the acid leaching treatment.

  (2) The second invention of the present invention is the first invention, wherein the mixture containing the chromite separated in the classification step is smaller than the magnetic field strength of the magnetic separation apparatus using the magnetic separation process. Using a low-field magnetic separation apparatus that generates magnetic field strength, further comprising a low-field magnetic separation process that separates a mixture containing magnetite as a magnetized material and separates a mixture containing chromite as a non-magnetized material, In the magnetic separation process, the mixture containing chromite as a non-magnetized product is separated from the mixture containing the chromite separated through the low magnetic separation process, and the mixture containing magnetite separated in the low magnetic separation process Is included in the ore slurry to be subjected to the acid leaching treatment.

  (3) According to a third aspect of the present invention, in the first or second aspect, in the classification step, a hydrocyclone is used as the classification device, and the mixture containing the goethite is separated as an overflow of the hydrocyclone. Then, the ore slurry is treated by separating the mixture containing the chromite as underflow.

  (4) According to a fourth aspect of the present invention, in the third aspect, in the classification step, among the underflow particles, an abundance ratio of particles having a particle size of −45 μm is 30% or less. An ore slurry treatment method comprising adjusting a pressure and a concentration of ore slurry to be classified.

  (5) A fifth invention of the present invention is a method for hydrometallurgy of nickel oxide ore, wherein the nickel oxide ore slurry is subjected to an acid leaching treatment and leached to recover nickel, and prepared from the nickel oxide ore. The ore slurry includes a treatment step of ore slurry that separates chromite from the ore slurry subjected to the acid leaching treatment, and the ore slurry treatment step includes a classification device for the ore slurry prepared from the nickel oxide ore. Separation of the mixture containing magnetite as a magnetized product from the mixture containing the chromite by the classification process to obtain the mixture containing goethite and the mixture containing chromite from the mixture containing the chromite And a magnetic separation process that separates a mixture containing chromite as a non-magnetized product, and obtained in the classification process. A nickel oxide ore hydrometallurgical smelting method characterized in that a mixture containing the goethite and a mixture containing the magnetite separated in the magnetic separation process are used as ore slurry for the acid leaching treatment. .

  ADVANTAGE OF THE INVENTION According to this invention, the chromite in the ore slurry used for an acid leaching process can be reduced efficiently and effectively. As a result, wear of equipment such as piping and pumps used for transferring ore slurry can be suppressed, and the amount of final neutralization residue produced from the final neutralization step in the hydrometallurgical process can be reduced. Can do.

It is process drawing which shows an example of the hydrometallurgical process of nickel oxide ore. It is process drawing which shows an example of the processing method of an ore slurry. It is process drawing which shows an example of the hydrometallurgical process of the nickel oxide ore to which the processing method of an ore slurry is applied.

  Hereinafter, a specific embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention.

<< 1. Treatment method of ore slurry >>
The processing method of the ore slurry according to the present embodiment is a method for processing an ore slurry that is subjected to an acid leaching process under high temperature and high pressure, for example, in a hydrometallurgical process using nickel oxide ore as a raw material. This is a pretreatment method prior to the acid leaching treatment.

  Specifically, this ore slurry treatment method, as shown in the process diagram of FIG. 2, performs classification using a classifier on the nickel oxide ore slurry, and a mixture containing goethite and a mixture containing chromite. Are separated from the mixture containing chromite obtained in the classification step S21 and the chromite obtained in the classification step S21 by using a magnetic separator, and the chromite is contained as a non-magnetized product. And magnetic separation process S23 for separating the mixture.

  Moreover, in this ore slurry processing method, following the classification step S21, a low magnetic field that generates a magnetic field strength smaller than the magnetic field strength of the magnetic separation apparatus used in the magnetic separation process S23 is applied to the mixture containing classified and separated chromite. It is possible to provide a low-field magnetic separation process S22 that separates a mixture containing magnetite as a magnetized product and separates a mixture containing chromite as a non-magnetized product using a magnetic sorting apparatus.

  Nickel oxide ore that is a raw material to be processed in the hydrometallurgical process of nickel oxide ore is mainly so-called laterite ore such as limonite or saprolite ore. The nickel content of the laterite ore is usually 0.8 to 2.5% by weight, and nickel is contained as a hydroxide or a hydrous silicic clay (magnesium silicate) mineral. Further, 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 hydrous silicic clay. .

  Further, the laterite ore contains chromium, and most of the chromium content is contained as a chromite mineral containing iron or magnesium, for example, about 1 to 5% by weight. Further, the magnesia content is contained in hydrous silicic clay minerals as well as silicic clay minerals that are unweathered and contain almost no nickel which has high hardness. Silicic acid content is contained in silica minerals such as quartz and cristobalite (amorphous silica) and hydrous silicic clay.

  Thus, the chromite mineral, siliceous clay mineral, and silica mineral contained in the laterite ore are so-called gangue components that hardly contain nickel.

  In the nickel oxide ore hydrometallurgical process, the raw material nickel oxide ore, which is mainly a laterite ore, is mixed with water after the ore particle size is adjusted, and is prepared as an ore slurry. Contains chromite as described above. It is known that when such ore slurry containing chromite is transferred using equipment such as pipes and pumps to be subjected to acid leaching treatment, the equipment is remarkably worn out, and maintenance and operation efficiency of equipment are improved. It has a big effect.

  For this reason, as the ore slurry used for the acid leaching treatment, it is desirable to use one obtained by separating and removing the chromite component prior to the acid leaching treatment.

  Here, each component distribution state in the ore particle which comprises an ore slurry is demonstrated. When the nickel oxide ore is observed by EPMA, the portion having a high chromium content has a high ratio of being present as a single phase independent of the portion having a high iron content, and is often contained in an ore having a particle size of 20 to 1000 μm. . This indicates that the mineral containing chromium is contained in a large amount in particles of about 20 μm or more, while the mineral containing nickel and iron is contained in a large amount in particles of less than about 20 μm.

  Therefore, in order to effectively separate and recover chromite from the ore slurry, the ore after removing coarse particles from the nickel oxide ore used as a raw material is slurried, and the nickel oxide ore in the ore slurry is adjusted to an appropriate particle size. It is important to set the appropriate classification particle size. In addition, although the crushing particle size at this time is determined in consideration of the original purpose in forming the ore slurry, it is preferably about 2 mm or less.

  Table 1 shows an example of the ore particle size distribution of the ore slurry obtained by crushing the raw material nickel oxide ore to a particle size of about 2 mm or less, and the quality of the metal element component in each particle size category.

  As shown in Table 1, it can be seen that chromium, silicon, magnesium and the like are concentrated in the coarse grain portion of 75 μm or more in the ore in the ore slurry. On the other hand, it can be seen that iron is concentrated in the fine-grained portion of 75 μm or less.

  From this, first, for example, 2 mm or less ore slurry obtained by adjusting the particle size of the raw material nickel oxide ore is subjected to classification treatment with a predetermined classification particle size (classification point) using a classification device, Classification into coarse and fine grained parts. Then, a mixture containing chromite in the coarse-grained portion can be obtained, and a mixture containing goethite containing iron in the fine-grained portion can be obtained. Thereby, a chromite can be isolate | separated from an ore slurry as a 1st step. Hereinafter, more specifically, a classification process for performing such classification processing will be described.

<1-1. Classification process>
In the classification step S21, the ore slurry of nickel oxide ore is subjected to classification using a classification device, and classified into a mixture containing goethite and a mixture containing chromite. The mixture containing goethite classified here is an ore slurry from which chromite has been separated and removed, and the ore slurry supplied to an acid leaching process performed in a pressure reaction vessel such as an autoclave in a hydrometallurgical process as it is, Become.

  In the classification step S21, classification and separation can be performed into a mixture containing goethite and a mixture containing chromite by determining the operating conditions using a classification device. In this classification treatment, based on a predetermined classification particle size, the fine-grained portion becomes a mixture containing goethite, and the coarse-grained portion becomes a mixture containing chromite and separated. In addition, the mixture containing chromite classified into the coarse-grained portion mainly contains chromite and magnetite, and a part of goethite mixed in the coarse-grained portion is included.

  Specifically, the classification process in the classification step S21 is not particularly limited, but it is preferable that the chromite concentration in the mixture containing chromite is concentrated to about 41% by weight or more.

  Specifically, regarding the operating conditions of the classifier, the classification particle size (classification point) of the ore slurry to be processed is not limited as long as the goethite containing nickel can be efficiently classified and separated as a fine particle part, and preferably 20 to It is preferable to select from the range of 150 μm, more preferably from 45 to 75 μm. That is, the lower limit of the classification particle size that can be industrially implemented is approximately 20 μm. From this, when the classified particle size is less than 20 μm, the concentration of chromite to the coarse portion becomes insufficient and nickel in the ore slurry supplied to the acid leaching process is lost. On the other hand, if the classified particle size exceeds 150 μm, the removal of chromite, siliceous clay, and silica minerals may be insufficient in the fine-grained portion.

  Although it does not specifically limit as a classification apparatus, It is preferable to use a hydrocyclone. In general, the specific gravity of chromite is larger than the specific gravity of iron hydroxide such as goethite, and by performing classification using a hydrocyclone, the ore slurry is chromite as underflow (U / F) based on the particle size. As a result, the mixture containing goethite can be separated with high accuracy from the mixture containing. Hydrocyclone is suitable for processing a large amount of ore slurry, and also suitable for processing when there are many distributions to the overflow. Note that the hydrocyclone may have only one stage, or may have two or more stages.

  The operating pressure of a classifier such as a hydrocyclone, that is, the pressure of the slurry supplied to the classifier is not particularly limited, but is preferably about 0.1 to 0.3 MPa in consideration of classification performance, processing speed, and the like. .

  Moreover, as a classifier, it is preferable to adjust the shape etc. so that the pulp density of an underflow may be 50 weight% or more.

  Moreover, it is although it does not specifically limit as a pulp density | concentration of the ore slurry used for classifiers, such as a hydrocyclone, It is preferable about 10-30 weight%, and it is more preferable that it is 15-20 weight%. For example, in classification separation using a hydrocyclone, treatment is possible even if the pulp concentration is less than 10% by weight, but a large amount of water is required, and further, it is disadvantageous for sedimentation concentration in the subsequent step. On the other hand, if the pulp concentration exceeds 30% by weight, the viscosity of the slurry increases and classification separation may be difficult. For these reasons, it is preferable to set the pulp concentration in the range of 10 to 30% by weight, so that it is not necessary to supply new water and a tank for dilution is not required.

  Moreover, in performing the classification treatment, it is preferable to adjust the operating pressure and the like in consideration of the classification performance of the classification device and the processing speed as described above, among them, among the particles of the coarse portion obtained, It is preferable to adjust the slurry pressure supplied to the classifier and the concentration of the ore slurry to be classified so that the existence ratio of particles having a particle size of −45 μm (less than 45 μm) is 30% or less.

  In addition, in the particles classified into the coarse particles, it is desirable that the existence ratio of particles having a particle size of less than 45 μm is closer to 0%, but as the proportion of particles having a particle size of less than 45 μm is lowered, the separated fine particles Coarse particles of low nickel content may be mixed in the portion, which may cause nickel recovery loss in the hydrometallurgical process.

  In this way, by optimizing the pulp concentration, the operating pressure of the classifier such as hydrocyclone, the shape of the classifier, etc., it becomes possible to eliminate the distribution of chromite to the fine-grained portion, effectively reducing chromite. Can be separated.

<1-2. Magnetic beneficiation process>
In the magnetic separation process S23, the magnetic separation process is performed on the mixture containing chromite separated in the classification process S21 using a magnetic separation apparatus.

  As described above, the mixture containing chromite classified and separated as the coarse part in the classification step S21 mainly includes chromite and magnetite, and partly includes goethite. In the magnetic separation process S23, a mixture containing magnetite as a magnetized product can be separated by subjecting the mixture containing chromite to a magnetic separation process, and a mixture containing chromite as a non-magnetized product is separated. can do. By such magnetic separation process, chromite can be effectively separated, in other words, chromite can be further concentrated. On the other hand, the mixture containing magnetite as the separated magnetized material can be used as an ore slurry to be supplied to the acid leaching process of the hydrometallurgical process.

  In addition, goethite that is contained in a small amount in the mixture containing chromite, which is the target of magnetic separation process, will be included in the mixture containing magnetite by this magnetic separation process, and as with magnetite, acid leaching treatment Ore slurry to be supplied to

  As the magnetic separation apparatus, a high magnetic field separation apparatus that generates a relatively high magnetic field is used. Specifically, the high magnetic field magnetic separation apparatus is not particularly limited, but it is preferable to generate a magnetic field strength of 5 KGaus or higher. Thereby, magnetite can be effectively separated as a magnetized material. On the other hand, if the magnetic field strength is too high, the chromite to be separated may be magnetized at the same time. Therefore, the magnetic field strength of the high magnetic field magnetic separator is preferably 20 kGauss or less. Thus, chromite can be separated and removed more effectively by performing the magnetic separation process using a magnetic separation apparatus having a magnetic field strength in the range of 5 to 20 KGaus.

<1-3. Low magnetic field magnetic separation process>
Now, in the magnetic separation process using the high magnetic field magnetic separation apparatus in the magnetic separation process S23, both magnetite and goethite are separated and removed from the mixture containing chromite obtained by the classification process in the classification process S21. The magnetite can be separated as a magnetized material as described above. Although the effect of magnetic separation with magnetite as a magnetized material is greater than when processed using a magnetic separation apparatus having a relatively low magnetic field strength, it is difficult to remove magnetite from the magnet if the magnetic field strength is too high. On the other hand, goethite is not magnetized by magnetic separation with a magnetic separator with a relatively low magnetic field strength, but is magnetized with magnetic separation with a magnetic separator with a high magnetic field strength.

  Therefore, in the ore slurry processing method according to the present embodiment, as shown by the dotted line encircled portion in the process diagram of FIG. 2, following the classification step S21 using a classification device such as a hydrocyclone. It is preferable to provide a low magnetic field magnetic separation process S22.

  In the low magnetic field beneficiation process S22, the low magnetic field beneficiation apparatus that generates a magnetic field strength smaller than the magnetic field intensity of the magnetic beneficiation apparatus used in the magnetic beneficiation process S23 described above was obtained through the classification process S21. Magnetic beneficiation treatment is performed on the mixture containing chromite. By magnetic separation using this low-field magnetic separation apparatus, a mixture containing magnetite, which is a ferromagnetic material, can be separated as a magnetized product, and a mixture containing chromite and goethite can be separated as a non-magnetized product. can do.

  Thus, in the low magnetic field magnetic beneficiation step S22, magnetite that is a ferromagnetic material can be separated and removed efficiently, and the mixture containing the separated magnetite is supplied to the acid leaching process of the hydrometallurgical process. It can be.

  The low magnetic field magnetic separation apparatus is not particularly limited as long as it generates a magnetic field intensity smaller than the magnetic field intensity of the magnetic separation apparatus used in the magnetic separation process S23, but can operate with a magnetic field intensity of about 500 to 2000 Gauss. Is preferred. The magnetic separation process using the low magnetic field magnetic separation apparatus is a process for selectively removing the magnetite of the ferromagnetic material. However, if the magnetic field strength of the apparatus used is less than 500 Gauss, it is difficult to obtain the effect. On the other hand, when the magnetic field strength exceeds 2000 Gauss, it becomes difficult to remove the magnetite that has become a magnetized material from the magnet.

  In the low magnetic field magnetic separation process S22, the mixture containing chromite and goethite separated as a non-magnetized product is sent to the process in the magnetic separation process S23 described above. Specifically, in the magnetic separation process S23, the mixture containing chromite and goethite is subjected to a magnetic separation process using a magnetic separation apparatus in the range of, for example, 5 to 20 KGaus, and as a result, the mixture is used as a magnetized product. The mixture containing sites is separated, and the mixture containing chromite as non-magnetized material is separated.

  In addition, the mixture containing chromite and goethite separated in the low magnetic field magnetic separation process S22 may contain magnetite. In such a case, by the process in the magnetic separation process S23, Magnetite is also contained and separated in the mixture containing goethite obtained as a magnetized product.

  Thus, the ore slurry processing method according to the present embodiment performs classification using a classification device on the nickel oxide ore slurry to obtain a mixture containing goethite and a mixture containing chromite. Step S21 and a magnetic separation process S23 for separating a mixture containing magnetite as a magnetized product and a mixture containing chromite as a non-magnetized product from a mixture containing the obtained chromite using a magnetic separation apparatus Have More preferably, as the low magnetic field magnetic separation process S22, a low magnetic field magnetic separation apparatus that generates a magnetic field strength smaller than the magnetic field intensity of the magnetic separation apparatus that uses the classified and separated chromite mixture in the magnetic separation process S23. Is used to separate a mixture containing magnetite as a magnetized material and a mixture containing chromite as a non-magnetized material.

  Prior to subjecting ore slurry of nickel oxide ore to acid leaching treatment in a hydrometallurgical process, chromite in ore is separated efficiently and effectively by subjecting the ore slurry to such a series of treatments. Can be removed. Then, other separation components, that is, the mixture containing goethite classified and separated in the classification step S21 and the mixture containing magnetite as the magnetized material separated in the magnetic separation process S23 are subjected to acid leaching treatment. By using the ore slurry to be provided, it is possible to prevent wear of equipment such as piping and pumps used in the acid leaching process while suppressing a decrease in the actual yield of nickel.

  Moreover, since the chromite in the ore slurry can be effectively removed, the amount of residue generated in the hydrometallurgical process, particularly the final neutralization residue obtained through the final neutralization step can be reduced.

  Below, the hydrometallurgical process of the nickel oxide ore which applied the processing method of the ore slurry mentioned above is demonstrated concretely.

≪2. Nickel oxide ore hydrometallurgical process >>
The hydrometallurgical process of nickel oxide ore is a smelting process in which nickel is leached and recovered from nickel oxide ore using, for example, a high-pressure acid leaching method (HPAL method).

  FIG. 3 is a process diagram showing an example of the flow of a hydrometallurgical process by high pressure acid leaching of nickel oxide ore. As shown in the process diagram of FIG. 3, the hydrometallurgical process of nickel oxide ore is an ore treatment step S1 for slurrying nickel oxide ore, and an acid leaching treatment is performed under high temperature and high pressure by adding sulfuric acid to the ore slurry. Leaching step S3, solid-liquid separation step S4 for obtaining a leachate containing an impurity element together with nickel by separating the residue while washing the obtained leach slurry in multiple stages, and neutralizing starch containing an impurity element by adjusting the pH of the leachate Neutralization step S5 to obtain a post-neutralization solution containing nickel by separating the product, and a sulfide (zinc sulfide starch) containing zinc and a mother liquor for nickel recovery by adding a sulfiding agent to the post-neutralization solution A zinc removing step S6 and a sulfurating step S7 for generating a sulfide (nickel sulfide) containing nickel by adding a sulfurizing agent to the mother liquor for nickel recovery. Further, this hydrometallurgical process collects the leach residue slurry separated in the solid-liquid separation step S4 and the poor liquor discharged in the sulfidation step S7, renders them harmless and produces a final neutralization residue. It has a neutralization step S8.

  And in this Embodiment, before performing the acid leaching process by the sulfuric acid with respect to an ore slurry, the ore slurry processing process S2 which performs the process which removes a chromite with respect to the ore slurry slurried in the ore processing process S1. It is characterized by having.

(1) Ore treatment process In the ore treatment process S1, the nickel oxide ore that is the raw ore is classified at a predetermined classification point to remove the oversized ore particles, and then water is added to the undersized ore particles. To make a coarse ore slurry.

  Here, the nickel oxide ore which is a raw material ore is an ore containing nickel and cobalt, and as described above, is mainly a so-called laterite ore such as limonite or saprolite ore. The nickel content of the laterite ore is about 0.8 to 2.5% by weight, and nickel is contained as a hydroxide or a hydrous siliceous clay (magnesium silicate) mineral. Further, 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 hydrous silicic clay. .

  Further, the laterite ore contains chromium, and most of the chromium content is contained as a chromite mineral containing iron or magnesium, for example, about 1 to 5% by weight. Further, the magnesia content is contained in hydrous silicic clay minerals as well as silicic clay minerals that are unweathered and contain almost no nickel which has high hardness. Silicic acid is contained in silica minerals such as quartz and cristobalite (amorphous silica) and hydrous silicic acid clay minerals.

  The method for classifying nickel oxide ore is not particularly limited as long as it can classify the ore based on the desired particle size, and for example, it can be performed by sieving using a grizzly or vibrating sieve. Further, the classification point is not particularly limited, and a classification point for obtaining an ore slurry composed of ore particles having a desired particle size or less can be appropriately set.

(2) Ore Slurry Treatment Process In this embodiment, chromite is separated from the ore slurry obtained through the ore treatment process S1 prior to the acid leaching process in the leaching process S3. It is characterized by performing a removal process.

  In the ore slurry treatment step S2, the ore slurry is subjected to a classification treatment using a classification device to obtain a mixture containing goethite and a mixture containing chromite, and the chromite obtained in the classification step S21. And a magnetic separation process S23 that separates a mixture containing magnetite as a magnetized product and a mixture containing chromite as a non-magnetized product using a magnetic separation apparatus.

  In addition, the ore slurry processing step S2 is a low magnetic field magnetic force that generates a magnetic field strength smaller than the magnetic field strength of the magnetic ore separation apparatus that uses the classified and separated chromite mixture in the magnetic ore separation step S23 following the classification step S21. You may make it provide the low magnetic field magnetic separation process S22 which isolate | separates the mixture containing a magnetite as a magnetized material and isolate | separates the mixture containing a chromite as a non-magnetized material using a beneficiation apparatus.

  The detailed description of the chromite removal process in the ore slurry processing step S2 is the same as described above, and is omitted here. By performing the process on the ore slurry in this manner, the chromite is removed from the ore slurry. Separation and removal can be performed efficiently and effectively, and wear of equipment such as pipes and pipes can be prevented when the acid leaching treatment is performed on the ore slurry while suppressing a decrease in the actual nickel yield. It is also possible to reduce the amount of final neutralization residue finally obtained in the hydrometallurgical process.

  In the ore slurry processing step S2, the mixture containing goethite classified and separated in the classification step S21 and the mixture containing magnetite separated as a magnetized product in the magnetic separation process S23 are leached in the leaching step S3 described later. The ore slurry is supplied to the process. In addition, these ore slurries are charged into a pressure reaction vessel such as an autoclave that performs acid leaching through a pipe with pressure by a pump.

(3) Leaching step In the leaching step S3, an acid leaching treatment using, for example, a high-pressure acid leaching method is performed on the ore slurry from which chromite has been separated and removed through the ore slurry treatment step S2. Specifically, sulfuric acid is added to the raw ore slurry in a pressure reaction vessel such as an autoclave, and the ore slurry is pressurized while being pressurized at a high temperature of 220 to 280 ° C, preferably 240 to 270 ° C. Stir to produce a leach slurry consisting of the leachate and leach residue.

  In the leaching process in the leaching step S3, a leaching reaction represented by the following formulas (i) to (iii) and a high-temperature thermal hydrolysis reaction represented by the following formulas (iv) and (v) occur, such as nickel and cobalt. Leaching as sulfate and immobilization of leached iron sulfate as hematite are performed.

・ Leaching reaction MO + H ₂ SO ₄ ⇒MSO ₄ + H ₂ O (i)
(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 (ii)
FeO + H ₂ SO ₄ → FeSO ₄ + H ₂ O (iii)
-High-temperature thermal hydrolysis reaction 2FeSO ₄ + H ₂ SO ₄ + 1 / 2O ₂ ⇒Fe ₂ (SO ₄ ) ₃ + H ₂ O (iv)
_{Fe 2 (SO 4) 3 +} 3H 2 O⇒Fe 2 O 3 + 3H 2 SO 4 ··· (v)

  The amount of sulfuric acid used in the acid leaching treatment is not particularly limited, and is slightly larger than the chemical equivalent required for iron in the ore to be leached and changed to hematite, for example, 300 to 1 per ton of ore. 400 kg is used. In particular, if the amount of sulfuric acid added per ton of ore exceeds 400 kg, the sulfuric acid cost and the neutralizing agent cost in the subsequent process increase, which is not preferable. The amount of sulfuric acid used from the viewpoint of the product is set so that the concentration of free sulfuric acid at the end of leaching is 25 to 50 g / L, preferably 35 to 45 g / L. By satisfying such conditions, the true density of the leach residue can be increased to stably produce a high density leach residue and improve the solid-liquid separation property of the slurry. The equipment in S4 can be simplified.

  Here, in the acid leaching treatment, the ore slurry obtained through the ore slurry treatment step S2 is transferred to, for example, an autoclave through equipment such as piping. At this time, if chromite is contained in the ore slurry, the equipment such as the pipes and pumps are remarkably worn, increasing the repair frequency and increasing the maintenance cost. In addition, it is necessary to stop the operation of the plant at the time of repair, which is a major factor that deteriorates the operation efficiency.

  In this respect, in the present embodiment, chromite is efficiently and effectively separated and removed from the ore slurry in the ore slurry treatment step S2, and therefore, the ore slurry in the ore slurry subjected to the acid leaching treatment in the leaching step S3. Chromite is reduced. As a result, when the ore slurry is transferred through equipment such as piping, it is possible to suppress wear of equipment such as piping and to prevent a reduction in operation efficiency.

(4) Solid-liquid separation process In the solid-liquid separation process S4, the leaching liquid containing the impurity element in addition to nickel and cobalt is separated from the leaching residue while washing the leaching slurry obtained through the leaching process S3 in multiple stages.

  In the solid-liquid separation step S4, for example, after mixing the leaching slurry and the cleaning liquid, a solid-liquid separation process is performed by a solid-liquid separation facility such as a thickener. 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 the solid-liquid separation process, for example, an anionic flocculant may be added.

  In the solid-liquid separation step S4, it is preferable to perform solid-liquid separation while washing the leaching slurry in multiple stages. As the multistage cleaning method, for example, a continuous countercurrent cleaning method in which the cleaning liquid is brought into contact with the leaching slurry in a countercurrent flow 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. Further, 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. For example, as the cleaning liquid, preferably, the poor liquid obtained in the subsequent sulfurization step S7 can be used repeatedly.

(5) Neutralization step In the neutralization step S5, the pH of the leachate separated in the solid-liquid separation step S4 is adjusted, the neutralized starch containing impurity elements is separated, and after neutralization containing nickel and cobalt Obtain a liquid.

  Specifically, in the neutralization step S5, the pH of the resulting neutralized solution is 4 or less, preferably 3.0 to 3.5, more preferably 3.1 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, and a neutralized starch slurry containing trivalent iron, aluminum, or the like as an impurity element is formed after the neutralization. In the neutralization step S5, impurities are removed as neutralized starch in this way, and a neutralized final solution that becomes a mother liquor for nickel recovery is generated.

(6) Zinc removal step In the zinc removal step S6, a sulfurizing agent such as hydrogen sulfide gas is added to the neutralized final solution obtained in the neutralization step S5 prior to separating nickel and cobalt as sulfides. Thus, a sulfurization reaction is caused to produce a sulfide containing zinc, and a slurry of the zinc sulfide starch and a mother liquor for recovering nickel are produced.

  In the treatment in the zinc removal step S6, the speed of the sulfidation reaction is suppressed by creating weak conditions during the sulfidation reaction, and the coprecipitation of nickel having a higher concentration than zinc is suppressed. This selectively removes zinc from the neutralized final solution. The zinc sulfide starch slurry obtained by this zinc removal treatment can be transferred to the final neutralization step S8 for treatment in the same manner as the neutralized starch slurry obtained in the neutralization step S5.

(7) Sulfurization step In the sulfidation step S7, a sulfidizing agent such as hydrogen sulfide gas is added to the nickel recovery mother liquor obtained through the zinc removal step S6 to cause a sulfidation reaction, which contains nickel and cobalt. A sulfide (hereinafter also referred to as “nickel / cobalt mixed sulfide”) and a poor solution are generated.

  The mother liquor for recovering nickel is a sulfuric acid acidic solution from which the impurity components have been reduced from the leachate through the neutralization step S5 and the zinc has been removed through the zinc removal step S6. The nickel recovery mother liquor may contain about several g / L of iron, magnesium, manganese, etc. as impurity components, but these impurity components are sulfided with respect to the recovered nickel and cobalt. Therefore, it is not contained in the resulting nickel / cobalt mixed sulfide.

  The sulfiding treatment in the sulfiding step S7 is performed in a nickel and cobalt recovery facility. The recovery equipment includes, for example, a sulfurization reaction tank that performs a sulfurization reaction by blowing hydrogen sulfide gas or the like into the mother liquor, and a solid-liquid separation tank that separates and recovers the nickel / cobalt mixed sulfide from the liquid after the sulfurization reaction. The solid-liquid separation tank is constituted by, for example, a thickener or the like, and by subjecting the slurry after the sulfurization reaction containing the generated sulfide to sedimentation separation, the nickel-cobalt mixed sulfide as a precipitate is removed at the bottom of the thickener. More separated and recovered. 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 a final neutralization step S8, which will be described later, and detoxified.

(8) Final neutralization step In the final neutralization step S8, the poor pH containing impurity elements such as iron, magnesium and manganese discharged in the sulfurization step S7 described above is within a predetermined pH range that satisfies the discharge standard. Apply neutralization treatment (detoxification treatment) to be adjusted. In this final neutralization step S8, the leach residue slurry discharged from the solid-liquid separation process in the solid-liquid separation step S4 can also be processed together. Moreover, the slurry of the zinc sulfide starch obtained in zinc removal process S6 can also be processed as needed.

  The method of detoxification treatment in the final neutralization step S8, that is, the pH adjustment method is not particularly limited, but for example, by adding a neutralizing agent such as calcium carbonate (limestone) slurry or calcium hydroxide (slaked lime) slurry. It can be adjusted to a predetermined range. Specifically, the pH is adjusted to about 8-9.

  By the neutralization treatment using such a neutralizing agent, a final neutralization residue is generated and stored in the tailing dam. On the other hand, the neutralized solution satisfies the discharge standard and is discharged out of the system.

  Here, the final neutralization residue produced in the final neutralization step S8 contains gypsum generated in the neutralization step S5 and the like in addition to impurity components such as hematite and chromite in the leaching residue. Naturally, if the amount of these impurity components is large, the amount of the final neutralization residue also increases, and the cost burden for the construction and maintenance of the tailing dam increases.

  In this regard, in the present embodiment, chromite is efficiently and effectively separated and removed from the ore slurry in the ore slurry processing step S2, so that in the ore slurry used for the acid leaching process in the leaching step S3. The chromite has been reduced. As a result, the amount of chromite in the leaching residue produced by the acid leaching treatment can also be suppressed, and therefore the amount of the final neutralization residue produced in the final neutralization step S8 can be effectively reduced. it can. As a result, the cost of construction and maintenance of the tailing dam can be suppressed, and efficient operation can be performed.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. In addition, the analysis of the metal in an Example and a comparative example was performed using the fluorescent X ray analysis method or the ICP emission analysis method.

≪Processing for ore slurry≫
[Example 1]
Ore used for acid leaching out of ore slurry prepared from nickel oxide ore when performing acid leaching treatment with sulfuric acid using an autoclave in a hydrometallurgical process of nickel oxide ore (refer to the flow chart of FIG. 1) Treatment of the ore slurry to separate chromite from the slurry (see the process diagram of FIG. 2) was performed.

(Classification process)
First, as a classification process, a hydrocyclone (MD-9 type, manufactured by Ataka Daiki Co., Ltd.) was subjected to classification treatment on ore slurry prepared from nickel oxide ore as a raw material for hydrometallurgy. In addition, in the hydrocyclone, the pressure was set to 0.1 MPa, 0.2 MPa, and 0.3 MPa, and classification treatment was performed under the respective conditions. In addition, Table 2 below shows the composition of the ore slurry that was subjected to the classification treatment.

A mixture containing goethite as hydrocyclone overflow (O / F) by classification using hydrocyclone, and a mixture containing chromite, magnetite and some goethite as hydrocyclone underflow (U / F) Were separated from each other. Table 3 below shows the abundance (wt%) of -45 μm particles contained in the hydrocyclone U / F after classification, and Table 4 below shows chromite (Cr ₂ O ₃ contained in the hydrocyclone U / F after classification. ) Concentration (wt%). In addition, Solid% (w / w) in Table 3 and Table 4 shows the solid content density | concentration in the ore slurry made into the object of a classification process.

As shown in Table 3 and Table 4, in this classification treatment, the hydrocyclone slurry pressure is 0.2 MPa or less, and the solid content concentration (Solid%) of the slurry is 23 wt% or less. In the coarse-grained part (hydrocyclone U / F) obtained by the above, the proportion of particles having a size of −45 μm is 30% or less, and the concentration of Cr ₂ O ₃ at this time is concentrated to 13.5% or more. I understand.

(Magnetic separation process)
Next, as a magnetic beneficiation process, the hydrocyclone U / F obtained by the classification process, that is, a magnetic beneficiation process using a high magnetic field magnetic beneficiation apparatus for a mixture containing chromite, magnetite and some goethite. Was given.

  Specifically, a hydrocyclone U / F slurry obtained by physical classification with the concentration of the ore slurry (solid content concentration) charged into the hydrocyclone being 23 wt% and the hydrocyclone slurry pressure being 0.2 MPa, Magnetic beneficiation treatment was performed using a 15 KGaus high magnetic field beneficiation device.

As a result, chromite could be separated as a non-magnetized substance, and the abundance ratio of the fine particles having a size of −45 μm in the non-magnetized substance was 5%. The Cr ₂ O ₃ concentration was 42% by mass.

[Example 2]
In Example 2, the concentration of the ore slurry (solid content concentration) charged into the hydrocyclone was 23% by weight, and the U / F slurry obtained by physical classification at a hydrocyclone slurry pressure of 0.2 MPa was low. As the magnetic field magnetic separation process, a magnetic separation process using a 1000 Gauss low magnetic field separation apparatus was performed.

By this magnetic separation process, a mixture containing chromite was obtained as a non-magnetized substance, the abundance ratio of fine particles having a size of −45 μm in the mixture was 15%, and the Cr ₂ O ₃ concentration was 32% by mass. .

  Then, the magnetic mixture beneficiation process using a 15 KGaus high magnetic field beneficiation apparatus was performed on the obtained mixture containing chromite, which is a non-magnetized substance, in the same manner as in Example 1.

As a result, chromite could be separated as a non-magnetized material, and the abundance ratio of -45 μm-sized fine particles in the non-magnetized material could be reduced to 4%. Further, the Cr ₂ O ₃ concentration increased to 44% by mass.

[Reference Example 1]
The U / F slurry obtained by physical classification with the ore slurry concentration (solid content concentration) of 23% by weight and hydrocyclone slurry pressure of 0.2MPa was processed with a 3KGaus high magnetic field magnetic separator. did.

As a result, although chromite could be separated as a non-magnetized material, the abundance ratio of fine particles having a size of −45 μm in the non-magnetized material was 12%, and the Cr ₂ O ₃ concentration was 34% by mass. Met.

[Reference Example 2]
The U / F slurry obtained by physical classification with the ore slurry concentration (solid content concentration) of 30% by weight and hydrocyclone slurry pressure of 0.3MPa was processed in a 15KGaus high magnetic field magnetic separator. did.

As a result, although chromite could be separated as a non-magnetized material, the abundance ratio of the fine particles of −45 μm size in the non-magnetized material was 10%, and the Cr ₂ O ₃ concentration was 38% by mass. Met.

≪Acid leaching treatment using ore slurry after treatment≫
[Example 3]
In the treatment of Example 1, the hydrocyclone O / F slurry obtained in the classification process and the magnetized slurry obtained in the magnetic separation process are used as an ore slurry to be subjected to an acid leaching treatment. I was charged. To this, sulfuric acid having a concentration of 98% was added, and high-temperature pressure sulfuric acid leaching was performed under the following conditions to obtain a leaching slurry.

(Leaching treatment conditions)
Leaching temperature: 245 ° C
Leaching time: 60 minutes Final (at the end of leaching) Free sulfuric acid concentration: 40 g / L
Ore slurry concentration (solid content concentration): 30% by weight
Autoclave capacity: 5L

  Next, the obtained leaching slurry was subjected to a solid-liquid separation treatment to separate into a leaching solution and a leaching residue slurry.

In order to know the quality of Cr ₂ O ₃ in the separated leaching residue slurry, Mg (OH) ₂ slurry having a concentration of 20% by weight was added as a neutralizing agent to the leaching residue slurry, and the pH of the slurry was adjusted at 70 ° C. Was neutralized to 2.5. Then, the slurry is subjected to solid-liquid separation using 5C filter paper, and after further adding Mg (OH) ₂ slurry to pH 6, further subjected to solid-liquid separation using 5C filter paper. A Japanese residue was obtained.

The final neutralization residue obtained had a Cr ₂ O ₃ grade of 0.8% by weight. Since the solubility of MgSO ₄ for generating a large, residual sulfur grade was 0.65 wt%.

[Comparative Example 1]
In Comparative Example 1, the ore slurry prepared from the nickel oxide ore used as a raw material was subjected to all the prepared ore slurry without performing classification treatment using a hydrocyclone or magnetic separation using a magnetic separation apparatus. The autoclave was charged as it was, and hot sulfuric acid leaching was performed. The conditions for the acid leaching treatment were the same as in Example 1.

  Then, the neutralization process was performed with respect to the leaching residue slurry obtained by solid-liquid separation, and the final neutralization residue was obtained similarly to Example 1.

When Cr ₂ O ₃ quality in the obtained final neutralization residue was measured, the Cr ₂ O ₃ quality was as high as 2.0% by weight. In addition, since the solubility of produced MgSO ₄ was large, the sulfur quality of the residue was 0.53% by weight.

As is clear from the comparison results of Example 3 and Comparative Example 1, the prepared ore slurry was subjected to a classification treatment by a classification device such as a hydrocyclone, and then the magnetic force was applied to the obtained mixture containing chromite. It was found that the chromite in the ore slurry can be effectively separated and removed by processing using the beneficiation device, and the quality of Cr ₂ O ₃ in the residue obtained through the acid leaching process can be reduced. .

  From this, it is expected that even when the ore slurry is transferred using a pipe, a pump or the like to be subjected to the leaching process, it is possible to prevent wear of these facilities. It is also expected that the amount of final neutralization residue can be reduced.

Claims (4)

A method for treating an ore slurry to be subjected to an acid leaching treatment in a hydrometallurgical method of nickel oxide ore,
Classifying the nickel oxide ore ore slurry using a classification device to obtain a mixture containing goethite and a mixture containing chromite;
The mixture containing the chromite separated in the classification step partially includes goethite, and the mixture containing the chromite is applied using a low-field magnetic separation apparatus that generates a magnetic field strength of 0.5 to 2 KGaus. A low-field magnetic separation process for separating a mixture containing magnetite as a magnetic material and a mixture containing chromite and goethite as non-magnetized materials;
From a mixture containing the chromite and goethite, and magnetic field strength by using a magnetic separator apparatus 5～20KGauss, magnetic separation to separate the mixture containing chromite as a mixture with non-wearing磁物containing goethite as Chaku磁物And having a process
A mixture containing the goethite obtained in the classification step, a mixture containing the magnetite separated in the low magnetic field magnetic separation process, and a mixture containing the goethite separated in the magnetic separation process, A method for treating an ore slurry, wherein the ore slurry is used for the acid leaching treatment. In the classification step, claim 1 using a hydrocyclone as the classifier, separating a mixture containing the goethite as an overflow of the hydrocyclone, and separating the mixture containing the chromite as underflow method of processing ore slurry according to. In the classification step, the hydrocyclone pressure and the concentration of the ore slurry to be classified are adjusted so that the abundance ratio of the underflow particles having a particle size of −45 μm is 30% or less. The processing method of the ore slurry of Claim 2 characterized by the above-mentioned. In the method of hydrometallurgy of nickel oxide ore, the acid leaching treatment is performed on the ore slurry of nickel oxide ore so that nickel is leached and recovered.
Of the ore slurry prepared from the nickel oxide ore, including a treatment step of ore slurry to separate chromite from the ore slurry to be subjected to the acid leaching treatment,
The ore slurry processing step includes:
Classifying step using a classifier for ore slurry prepared from the nickel oxide ore, and obtaining a mixture containing goethite and a mixture containing chromite;
The mixture containing the chromite separated in the classification step partially includes goethite, and the mixture containing the chromite is applied using a low-field magnetic separation apparatus that generates a magnetic field strength of 0.5 to 2 KGaus. A low-field magnetic separation process for separating a mixture containing magnetite as a magnetic material and a mixture containing chromite and goethite as non-magnetized materials;
From a mixture containing the chromite and goethite, and magnetic field strength by using a magnetic separator apparatus 5～20KGauss, magnetic separation to separate the mixture containing chromite as a mixture with non-wearing磁物containing goethite as Chaku磁物And having a process
A mixture containing the goethite obtained in the classification step, a mixture containing the magnetite separated in the low magnetic field magnetic separation process, and a mixture containing the goethite separated in the magnetic separation process, A method for hydrometallizing nickel oxide ore, characterized in that the slurry is ore used for the acid leaching treatment.

Images