JP7176595B1 - Method for producing ore slurry, hydrometallurgical method for nickel oxide ore - Google Patents

Abstract

An object of the present invention is to provide a method capable of effectively increasing the concentration of an ore slurry to be subjected to leaching treatment in hydrometallurgical refining of nickel oxide ore, for example, while suppressing the addition amount of a flocculant. Kind Code: A1 The present invention is a method for producing ore slurry by slurring nickel oxide ore, which includes a process of setting the D90 average particle size of nickel oxide ore to 60 μm or more and performing sedimentation and concentration of the ore slurry. In this production method, the amount of flocculant added in the sedimentation concentration is 80 g or less per ton of ore, and the concentration of the ore slurry is adjusted to 34% by mass or more. [Selection drawing] Fig. 2

Description

TECHNICAL FIELD The present invention relates to an ore slurry production method and a hydrometallurgical method for nickel oxide ore to which the production method is applied.

In the hydrometallurgical method based on high-temperature pressurized sulfuric acid leaching to recover nickel from low-grade nickel oxide ore, the ore supplied to the leaching process is taken out by a crusher or a wet sieve with a predetermined size or less, and the slurry is become.

In addition, the ore slurry is usually prepared by blending several types of ores so as to achieve a predetermined acid consumption, nickel (Ni) concentration of the leachate, and other impurity concentrations. However, since the slurry concentration (solid content rate) of the ore slurry obtained at this point is as low as about 10% by mass to 15% by mass, the Ni content is also relatively low, and if it is supplied as it is to the leaching process, it will be obtained. The amount of the leachate is large and the Ni concentration is low. A problem arises in that nickel cannot be efficiently recovered from such a leachate.

Therefore, the ore slurry with a low slurry concentration is supplied to the leaching step after performing a concentration operation to increase the slurry concentration using a sedimentation concentration device such as a thickener. In thickener, since the thickening behavior (sedimentation concentration in the thickener) differs depending on the type of ore, the type of ore blended, the blend ratio, the shape and size of the thickener used for thickening, the type and amount of flocculant used. etc.

The higher the slurry concentration of the ore slurry, the more nickel passes through the process in the leaching process per unit time, and the higher the nickel recovery efficiency. Therefore, the slurry concentration is required to be as high as possible.

In order to increase the slurry concentration, a flocculant is generally used for concentration. Since the main component of the flocculant is usually high-molecular hydrocarbon, the carbon grade in the liquid increases. The viscosity and carbon grade of the flocculant are factors that slow down the process in the leaching process. In general, it is desirable that the amount of the flocculant to be added is about 100 g/t-ore or less.

For example, in Patent Document 1, when an ore slurry containing an ore whose particle size is adjusted is charged into a thickener and concentrated, the addition amount of a flocculant to be added to the ore slurry and the temperature after concentration of the ore slurry are specified. Also disclosed is a technique for adjusting the concentration and viscosity of the ore slurry by specifying the molecular weight and pre-dilution rate of the flocculant.

JP 2012-153922 A

The present invention has been proposed in view of such circumstances. The purpose is to provide a method that can increase the

The inventor of the present invention has made extensive studies in order to solve the above-described problems. As a result, the particle size of the nickel oxide ore that constitutes the ore slurry affects the sedimentation speed in the process of sedimentation concentration, and the concentration of the ore slurry can be adjusted to a desired value by adjusting the particle size of the ore to have a specific particle size distribution. The inventors have found that the high concentration range can be efficiently adjusted, leading to the completion of the present invention.

(1) A first aspect of the present invention is a method of preparing an ore slurry by slurring a nickel oxide ore, wherein the nickel oxide ore has a D90 average particle size of 60 μm or more, and the ore slurry is subjected to sedimentation and concentration. A method for producing an ore slurry, comprising:

(2) A second aspect of the present invention is the first aspect, wherein the addition amount of the flocculant added in the sedimentation concentration is 80 g or less per ton of ore, and the concentration of the ore slurry is adjusted to 34% by mass or more. It is a method for producing an ore slurry.

(3) A third aspect of the present invention is the method for producing an ore slurry according to the first or second aspect, wherein the nickel oxide ore has an average D50 particle size of 10 μm or more.

(4) A fourth aspect of the present invention is the method according to any one of the first to third aspects, wherein ore particles having an average D90 particle size of less than 60 μm are added with ore particles having an average D90 particle size of greater than 60 μm and mixed. By doing so, the D90 average particle size of the nickel oxide ore is set to 60 μm or more, and the ore particles having the D90 average particle size larger than 60 μm are those on the large particle size side obtained by the classification operation by the classifier, the ore slurry is a manufacturing method.

(5) A fifth aspect of the present invention includes an ore slurry preparation step of slurrying nickel oxide ore to prepare an ore slurry, and a leaching step of adding sulfuric acid to the ore slurry and performing a leaching treatment. In the hydrometallurgical method for nickel oxide ore, the ore slurry preparation step includes a process of sedimentation and concentration of the ore slurry by setting the D90 average particle size of the nickel oxide ore to 60 μm or more.

(6) A sixth aspect of the present invention is the fifth aspect, wherein the amount of flocculant added in the sedimentation concentration is 80 g or less per ton of ore, and the concentration of the ore slurry is adjusted to 34% by mass or more. It is a method for hydrometallurgy of nickel oxide ore.

Advantageous Effects of Invention According to the present invention, it is possible to provide a method that can effectively increase the concentration of ore slurry to be subjected to leaching treatment in hydrometallurgical refining of nickel oxide ore, for example, while suppressing the amount of flocculant added. .

BRIEF DESCRIPTION OF THE DRAWINGS It is process drawing which shows an example of the flow of a nickel hydrometallurgical process. FIG. 4 is a graph showing the relationship between the amount of flocculant added and the slurry concentration when a sedimentation concentration test was conducted using two kinds of ores having different particle size distributions.

Specific embodiments of the present invention (hereinafter also referred to as "present embodiments") will be described in detail below. It should be noted that the present invention is not limited to the following embodiments, and modifications can be made as appropriate without changing the gist of the present invention.

≪1. Ore Slurry Manufacturing Method»
The method according to the present embodiment is a method of producing an ore slurry by slurring a nickel oxide ore (hereinafter also simply referred to as “manufacturing method”). This production method can be applied to treatment in an ore slurry preparation step for preparing an ore slurry to be subjected to leaching treatment in a leaching step in a nickel oxide ore hydrometallurgical process.

Specifically, the manufacturing method according to the present embodiment includes a process of sedimentation and concentration of ore slurry obtained by adding water to ore using a sedimentation and concentration apparatus such as a thickener. Such sedimentation concentration increases the slurry concentration of the ore slurry. In the production method according to the present embodiment, in the sedimentation concentration, the D90 average particle size of the nickel oxide ore is adjusted to 60 μm or more, and sedimentation concentration is performed on the ore slurry with the particle size adjusted. .

As a result of studies by the present inventors, it was found that the particle size of the nickel oxide ore that constitutes the ore slurry affects the sedimentation speed in the sedimentation concentration process, and that the particle size should be adjusted so that the specific particle size, that is, the D90 average particle size is 60 μm or more. , the concentration of the ore slurry (slurry concentration: solid content concentration in the ore slurry) can be efficiently adjusted to a desired high concentration range.

Moreover, according to the production method according to the present embodiment, it is possible to produce an ore slurry with an effectively increased slurry concentration without depending on the addition amount of the flocculant in the sedimentation concentration. Specifically, it is possible to adjust the slurry concentration to a high concentration of 34% by mass or more by reducing the amount of the flocculant added in the sedimentation concentration, for example, 80 g or less per ton of ore, which is smaller than the conventional amount. In other words, a highly concentrated ore slurry can be produced by an economically extremely efficient operation without increasing the chemical cost of the flocculant.

A method for adjusting the particle size of the nickel oxide ore is not particularly limited, and a known method can be used. For example, ore is crushed or crushed to a certain size, and then classified at a predetermined classification particle size (classification point) using a classifier.

In addition, it is not limited to adjusting the particle size by pulverizing ore or the like, and for example, ore particles having an average D90 particle size of less than 60 μm are mixed with ore particles having an average D90 particle size of more than 60 μm at a predetermined ratio. , the ore to be treated for sedimentation and concentration may be prepared. According to such a particle size adjustment method, a simple operation of adding ore particles having an appropriate particle size based on an operation such as sieving and mixing without performing a complicated operation such as pulverization or crushing. It is possible to perform efficient preparation of an object to be treated. In addition, since ore particles having a small particle size can also be treated, the range of application of ore particles as objects of sedimentation and concentration treatment can be expanded. At this time, the ore particles having a D90 average particle size larger than 60 μm (large particle size ore particles) to be added are those on the large particle size side obtained by the classification operation with a classifier (for example, the sieving operation with a 60 μm sieve). ore particles on a sieve to be classified), and the amount added is such that the D90 average particle size of the ore to be subjected to sedimentation and concentration treatment obtained by mixing is 60 μm or more.

By adjusting the particle size in this way, the D90 average particle size is set to 60 μm or more. The upper limit of the average particle size is preferably 100 μm or less, more preferably 90 μm or less, and particularly preferably 85 μm or less, from the viewpoint of enhancing the leaching efficiency. The D90 average particle size is the particle size where the volume of each particle is accumulated from the smaller particle size side, and the cumulative volume is 90% of the total volume of all particles (accumulated particle size distribution with the total volume as 100% When determining the curve, it means the particle size at which the cumulative curve reaches 90%). Also, the D90 average particle size can be obtained from, for example, a volume integrated value measured with a laser beam diffraction/scattering particle size analyzer.

The D90 average particle size of the nickel oxide ore can be easily controlled by sieving, and it is preferable to use a sieve with an opening that is 1 to 2 times the target D90 average particle size. For example, if the volume of ore particles before sieving has a uniform particle size distribution, the D90 average particle size is about 0.9 times the mesh size of the sieve. Further, when there are many small ore particles, the opening is about 0.5 times the sieve opening, and when there are many large ore particles, the opening is up to about 1.0 times the sieve opening. In the examples described later, it was 0.7 times (31/45) the opening of the sieve.

In addition, regarding the particle size of the nickel oxide ore, it is preferable to further satisfy the condition that the D50 average particle size is 10 μm or more. The D50 average particle size is more preferably 13 μm or more, particularly preferably 15 μm or more. The D50 average particle size is the particle size where the volume of each particle is accumulated from the smaller particle size side, and the cumulative volume is 50% of the total volume of all particles (accumulated particle size distribution with the total volume as 100% When determining the curve, it means the particle size at which the cumulative curve reaches 50%). Also, similarly to the D90 average particle size, the D50 average particle size can be determined from the volume integrated value measured with a laser beam diffraction/scattering particle size analyzer.

≪2. Hydrometallurgical method of nickel oxide ore»
The method for producing an ore slurry described above can be preferably applied, for example, to a process (ore slurry preparation step) for preparing ore slurry to be subjected to leaching treatment in a leaching step in a nickel oxide ore hydrometallurgical process. According to the production method according to the present embodiment, it is possible to prepare an ore slurry having a high slurry concentration while suppressing the chemical cost of the flocculant. , it is possible to increase the leaching efficiency of nickel and cobalt and improve the recovery rate.

A nickel oxide ore hydrometallurgical process is a smelting process in which nickel is leached and recovered from nickel oxide ore using, for example, high pressure acid leaching (HPAL). FIG. 1 is a process diagram showing an example of the flow of a nickel hydrometallurgical process.

The nickel oxide ore hydrometallurgical process includes an ore slurry preparation step S1 in which nickel oxide ore is slurried to prepare an ore slurry, and a leaching step S2 in which sulfuric acid is added to the ore slurry and acid leaching treatment is performed at high temperature and high pressure. a neutralization step S3 of adjusting the pH of the leachate to separate neutralized sediments containing impurity elements to obtain a post-neutralization solution containing nickel; and a nickel recovery step S4 for generating a sulfide containing nickel (nickel sulfide).

(1) Ore Slurry Preparing Step The ore slurry preparing step S1 is a step of preparing an ore slurry by adding water to the nickel oxide ore to be treated to form a slurry.

Nickel oxide ore, which is a raw material ore, is ore containing nickel and cobalt, and is mainly so-called laterite ore such as limonite ore and saprolite ore. Laterite ore has a nickel content of about 0.8% by mass to 2.5% by mass, and nickel is contained as a hydroxide or hydrated magnesium silicate (magnesium silicate) mineral. In addition, the content of iron is about 10% by mass to 50% by mass, and it is mainly in the form of trivalent hydroxide (goethite), but some divalent iron is contained in hydrous silicomagnesium minerals, etc. be done.

Here, in the present embodiment, in the ore slurry preparation step S1, the ore slurry obtained by slurrying is subjected to a concentration treatment using a sedimentation concentration apparatus such as a thickener. At this time, the particle size of the nickel oxide ore constituting the ore slurry is adjusted so that the D90 average particle size is 60 μm or more, and the particle size-adjusted ore slurry is subjected to sedimentation and concentration.

The preparation of the ore slurry is the same as the process in the ore slurry production method described in detail above, so the explanation is omitted here.

Preparing an ore slurry by carrying out sedimentation concentration by such a method makes it possible to prepare an ore slurry having a high slurry concentration while reducing the chemical cost of the flocculant. Specifically, the slurry concentration can be adjusted to a high concentration of 34% by mass or more while suppressing the addition amount of the flocculant to a small amount of 80 g or less per ton of ore.

(2) Leaching Step The leaching step S2 is a step of subjecting the ore slurry obtained through the ore slurry preparation step S1 to an acid leaching treatment using, for example, a high-pressure acid leaching method. Specifically, ore slurry is charged into a pressurized reaction vessel such as an autoclave, sulfuric acid is added thereto, and the ore slurry is stirred while being pressurized under high temperature conditions of about 220°C to 280°C. , to produce a leach slurry consisting of leachate and leach residue.

In the leaching treatment, leaching reactions represented by the following formulas (i) to (iii) and high-temperature thermal hydrolysis reactions represented by the following formulas (iv) and (v) occur, and sulfates such as nickel and cobalt are produced. Leaching and immobilization of the leached iron sulfate as hematite takes place.
・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 +3H2SO4→Fe2 _{( SO4} ) _{3 + 6H2O} ( _ii )
FeO+H2SO4→ _{FeSO4 + H2O (} iii)
- High-temperature thermal hydrolysis reaction 2FeSO4+H2SO4+1/ _2O2- >Fe2 _{( SO4} ) _{3 + H2O ( 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, but is slightly in excess of the chemical equivalent required for the iron in the ore to be leached and changed to hematite, for example, 300 to 400 kg per ton of ore. is used.

In the present embodiment, an ore slurry having a high slurry concentration is prepared, and the ore slurry is subjected to leaching treatment, so that the amount of sulfuric acid used is not excessively increased. And nickel and cobalt can be effectively leached.

The leaching slurry produced by the leaching process is subjected to solid-liquid separation while being washed in multiple stages, thereby separating the leaching solution containing nickel, cobalt and other impurity elements from the leaching residue.

(3) Neutralization Step The neutralization step S3 is a step of performing a neutralization treatment to adjust the pH of the leachate, separating neutralized sediment containing impurity elements, and obtaining a post-neutralization solution containing nickel and cobalt. be.

Specifically, in the neutralization step S3, while suppressing oxidation of the separated leachate, the resulting neutralized liquid has a pH of 4 or less, preferably 3.0 to 3.5, more preferably 3.1 to 3.1. 3. A neutralizing agent such as calcium carbonate is added to the leachate to produce a post-neutralization solution and a neutralized precipitate slurry containing trivalent iron, aluminum, etc. as impurity elements. In the neutralization step S3, impurities are thus removed as neutralized sediments to produce a final neutralization liquid that serves as a mother liquid for recovering nickel.

(4) Nickel Recovery Step In the nickel recovery step S4, a sulfiding agent such as hydrogen sulfide gas is added to the final neutralization solution, which is a mother liquor for nickel recovery, to cause a sulfurization reaction, thereby producing a sulfurization containing nickel and cobalt. It is a step of generating and recovering a substance (hereinafter also simply referred to as "nickel sulfide") and a poor liquid.

The mother liquor for recovering nickel is a sulfuric acid acid solution obtained by subjecting the leachate to the neutralization step S3 to reduce impurity components. The mother liquor for nickel recovery may contain several g/L of impurities such as iron, magnesium, and manganese. is low and therefore not included in the resulting nickel sulfide.

The sulfurization treatment in the nickel recovery step S4 is performed in a sulfurization reaction tank in which hydrogen sulfide gas or the like is blown into the mother liquor to carry out a sulfurization reaction. Slurry after the sulfurization reaction containing sulfides produced by the sulfurization reaction is subjected to sedimentation separation treatment, and nickel sulfide as a precipitate is separated and recovered from the bottom of the apparatus, while the aqueous solution component overflows. and collected as poor liquid. The recovered poor liquid is a solution with an extremely low concentration of valuable metals such as nickel, and contains impurity elements such as iron, magnesium, and manganese that remain without being sulfided.

If zinc is contained in the final neutralization solution obtained through the neutralization step, dezincification treatment for separating and recovering zinc as sulfide should be performed prior to the sulfurization treatment for generating nickel sulfide. may In the dezincification process, the reaction conditions such as the concentration of hydrogen sulfide gas are moderated during the sulfurization reaction to suppress the speed of the sulfurization reaction and to suppress the coprecipitation of nickel, which coexists at a high concentration compared to zinc. .

EXAMPLES The present invention will be more specifically described below with reference to examples, but the present invention is not limited to the following examples.

Using the nickel oxide ore whose chemical composition and specific gravity are shown in Table 1 below, an ore slurry to be subjected to leaching treatment in the nickel oxide ore hydrometallurgical process was prepared. Limonite ore is mainly used as a raw material in the leaching process by the high-temperature pressurized sulfuric acid leaching method. Some of them can be mixed and used depending on the degree of influence of the impurities.

A nickel oxide ore was pulverized by a pulverizer and sieved with a sieve having an opening of 45 μm and 1.4 mm. Table 2 below shows the particle size distribution under each sieve. Each average particle size of D10, D50, and D90 was obtained from the volume integrated value measured with a laser beam diffraction/scattering particle size analyzer. As shown in Table 2, the D90 average particle size of the ore particles under the 45 μm sieve was 31 μm, and the D90 average particle size of the ore particles under the 1.4 mm sieve was 62 μm.

The nickel oxide ore of each particle size thus obtained was diluted with pure water to prepare an ore slurry having a slurry concentration of 11% by mass. After that, a sedimentation concentration treatment was performed to increase the slurry concentration, and the sedimentation concentration behavior was investigated. The sedimentation concentration treatment was performed using a thickener, and an anionic flocculant PA804 (manufactured by Kurita Water Industries Ltd.) diluted with pure water to a concentration of 0.03% by mass was used as the flocculant. Specifically, a predetermined amount of flocculant was added to the ore slurry, the slurry was sedimented and concentrated, and the solid concentration in the sedimented ore slurry (slurry concentration shown in FIG. 2) was measured.

FIG. 2 shows the results of investigating the relationship between the addition ratio F _floc (unit: g·t ⁻¹ ) of the flocculant to the ore and the slurry concentration W (Underflow concentration, unit: mass %) for two types of particle size distributions. show.

As shown in FIG. 2, in the ore slurry consisting of the ore under the sieve of the 45 μm sieve, even if the addition amount of the flocculant was increased, the slurry concentration did not change, and the concentration was about 31% by mass. On the other hand, in the case of ore slurry consisting of ore under sieving by a 1.4 mm sieve (ore having a D90 average particle size of 60 μm or more), increasing the amount of flocculant added increases the slurry concentration, and The addition amount of the coagulant was as small as about 50 g/t-Ore, and the slurry concentration could be increased to 34% by mass or more.

The ore under the 1.4 mm sieve contains the same particles as the ore under the 45 μm sieve, but additionally contains ore particles of 45 μm or more, more preferably 60 μm or more. By containing 10% or more, it is considered that precipitation and concentration could be performed more efficiently and effectively. In other words, by containing ore particles of large particle size, ore particles of about 0 μm to 45 μm, which are relatively difficult to sedimentation and concentration, can be treated together, which is industrially useful.

From these results, if it is desired to sediment and concentrate ore particles with an average D90 particle size of less than 60 μm, ore particles having a large particle size on a sieve obtained by a classifier such as a 45 μm sieve or a 60 μm sieve are added. By doing so, it can be seen that the sedimentation concentration can be advanced more efficiently. The ore particles having a large particle size as referred to herein are ore particles having an average D90 particle size of 60 μm or more, and the amount added is such that the average D90 particle size of the ore particles to be sedimented and concentrated is 60 μm or more. .

Claims (3)

A method for producing an ore slurry by slurrying a nickel oxide ore, comprising:
including a process of precipitating and concentrating the ore slurry with the D90 average particle size of the nickel oxide ore of 60 μm or more,
By adding ore particles having an average D90 particle size of greater than 60 μm to ore particles having an average D90 particle size of less than 60 μm and mixing them, the nickel oxide ore has an average D90 particle size of 60 μm or more,
The ore particles having a D90 average particle size of greater than 60 μm are those on the large particle size side obtained by the classification operation using a classifier,
A method for producing ore slurry , wherein the amount of flocculant added in the sedimentation concentration is 80 g or less per ton of ore, and the concentration of the ore slurry is adjusted to 34% by mass or more . The D50 average particle size of the nickel oxide ore is 10 μm or more,
The method for producing an ore slurry according to claim 1 . an ore slurry preparation step of preparing an ore slurry by slurrying nickel oxide ore;
a leaching step of adding sulfuric acid to the ore slurry and subjecting the ore slurry to leaching;
The ore slurry preparation step includes a process of sedimentation and concentration of the ore slurry by setting the D90 average particle size of the nickel oxide ore to 60 μm or more,
By adding ore particles having an average D90 particle size of greater than 60 μm to ore particles having an average D90 particle size of less than 60 μm and mixing them, the nickel oxide ore has an average D90 particle size of 60 μm or more,
The ore particles having a D90 average particle size of greater than 60 μm are those on the large particle size side obtained by the classification operation using a classifier,
The amount of flocculant added in the sedimentation concentration is 80 g or less per ton of ore, and the concentration of the ore slurry is adjusted to 34% by mass or more.
A hydrometallurgical method for nickel oxide ore.

Images