JP2016006233A - Wet refining method of nickel oxide ore - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet refining method of a nickel oxide ore that allows the use of a base rock as a neutralizer in the neutralization process in the wet refining of the nickel oxide ore.SOLUTION: The wet refining method of the nickel oxide ore include a neutralization process. In the neutralization process, a neutralization residue is obtained by using a base rock as a neutralizer and carrying out the neutralization while adjusting the particle size of the base rock, in which hematite is concentrated in the particles with a smaller size, and the constituents of the nickel oxide ore other than the hematite are concentrated in the particles with larger size. Subsequent to the neutralization process, a wet classification process is provided to classify the neutralization residue.

Description

  The present invention relates to a method for hydrometallizing nickel oxide ore.

Nickel is widely used as a raw material for stainless steel.
However, with the tendency of the resources of the sulfide ore used as a raw material to be exhausted, technology for refining low-grade oxide ore has been developed and put into practical use.

  Specifically, nickel oxide ores such as limonite and saprolite are put into a pressure device such as an autoclave together with a sulfuric acid solution, and nickel is leached under a high temperature and high pressure of about 240 to 260 ° C., “high temperature pressure acid leaching (HPAL : High Pressure Acid Leach) ”has been put into practical use.

  Nickel leached into the sulfuric acid solution is neutralized with a neutralizing agent to neutralize excess acid, and then separated into leaching residue by solid-liquid separation, and then impurities and hydroxides and sulfides are separated. It is recovered as an intermediate material in the form of By further refining this intermediate raw material, nickel metal, nickel salt compounds, and the like are obtained.

In the pre-neutralization step of neutralizing the excess acid, the pH is adjusted to a suitable level for solid-liquid separation, and in the next solid-liquid separation step, the solid content is measured with equipment called CCD (Counter Current Decantation). Concentration and solid-liquid separation. Normally, a CCD uses a plurality of continuous thickeners.
The liquid component obtained from the CCD (hereinafter sometimes referred to as “overflow”) is sent to the neutralization process to adjust the pH to a suitable level for the sulfurization process. After removing the precipitate, for example, it is generally sent to a sulfidation step, and sulfidation is performed to obtain an intermediate raw material such as a mixed sulfide of nickel and cobalt.

  At this time, for example, in Patent Document 1, a part of the solid content obtained by CCD (hereinafter, sometimes referred to as underflow) is added as a seed crystal in the neutralization step to promote the formation of fine precipitates. The technology is described and is effectively used to improve the efficiency of actual operation.

  In such a manufacturing process called high pressure acid leaching (HPAL), for example, in the case of nickel oxide ore, a low-grade ore (hereinafter referred to as grade) with a valuable metal of 1 to 2 wt% or less for recovery purposes. Can be leached nickel almost completely.

Moreover, by producing the intermediate raw material from the leachate, the target metal can be concentrated to the same extent as the conventional raw material, and the target metal can be obtained by a refining method and process substantially the same as those of the conventional raw material.
This HPAL process can be applied not only to nickel oxide ore but also to many types such as nickel sulfide ore, copper sulfide ore, and copper oxide ore.

  Furthermore, the main component of the leaching residue obtained by the HPAL process is iron oxide in the form of hematite, etc. The iron content in the leaching residue is about 50%, and the amount of leaching residue produced is the production of intermediate raw materials About 50 to 100 times the amount. This is because both nickel oxide ore and copper sulfide ore used as raw materials contain iron far exceeding the content of nickel and copper.

This leaching residue is in the form of an oxide that is chemically and environmentally stable because it is generated at a high temperature, but currently has no particular utility value and is stored in a residue deposit site.
For this reason, a vast residue depositing place for storing and storing a huge amount of leaching residue generated with the operation of the HPAL process is required.

On the other hand, in iron and steel smelting, iron ore containing iron oxide is charged into a blast furnace together with a reducing agent such as coke, heated to reduce and melt to obtain crude steel, which is refined in a converter. A method of obtaining steel is used.
The raw iron oxide is a limited resource, and obtaining high-quality iron ore necessary for maintaining the quality of steel is becoming increasingly difficult. For this reason, the examination which uses a leaching residue as an iron ore is made | formed.

However, the leaching residue of the HPAL process could not be used directly for ironmaking raw materials.
The following two points can be cited as the reason.
(1) Since the leaching residue of the HPAL process contains gangue and impurities, particularly sulfur, in addition to iron oxide, it was not suitable as a raw material used in a conventional general iron making process.
(2) The average particle size of hematite recovered from the leaching residue is 1 μm or less and is very fine and difficult to handle.

By the way, iron ore can be divided into lump ore (6.3 to 31.5 mm), fine ore (1 to 6.3 mm), fine ore (0.05 to 0.1 mm) and charged into the blast furnace. There are three types of raw materials for iron making: lump ore, sintered ore, and pellets.
The sintered ore is produced by sintering fine ore, and the pellet is obtained by firing fine ore.
The sulfur grade in iron oxide that can be used for such ironmaking raw materials varies depending on the facility capacity, production amount, etc. of each ironworks, but it is generally required to be suppressed to less than 1%.

On the other hand, the leaching residue of the HPLA process usually contains about 5 to 8% sulfur.
The origin of sulfur in the leaching residue is calcium sulfate (gypsum), which is mostly mixed during nickel refining.
Gypsum is free sulfuric acid remaining in the leach slurry obtained by high-pressure acid leaching (free sulfuric acid is sulfuric acid that remains unreacted among sulfuric acid added excessively to perform sufficient leaching in the HPAL process. )), A general and inexpensive calcium-based neutralizer, such as limestone or slaked lime, is added, and is produced by the reaction of calcium and free sulfuric acid contained in the neutralizer. , It will be mixed in the leach residue.
In addition, a part (about 1%) of sulfur contained in the leaching residue is taken into the generated hematite particles.

Therefore, it is considered that the neutralizing agent to be added does not form a poorly soluble starch after neutralization, such as limestone or slaked lime, but uses a material that forms a soluble salt.
For example, there are sodium hydroxide, potassium hydroxide, magnesium hydroxide, magnesium oxide and the like as neutralizing agents suitable for such applications.

However, these neutralizing agents are not suitable for processes that consume a large amount of neutralizing agents, such as the HPAL process, for reasons such as high cost or low production.
For this reason, a calcium-based neutralizing agent that forms a poorly soluble starch after neutralization as described above must be used in whole or in part, and it is unavoidable that sulfur is mixed in. The resulting leach residue could not be processed into hematite and used as a raw material for iron making.

On the other hand, there is also known a method for separating sulfur in iron ore using a pressure device such as an autoclave.
For example, Patent Document 2 stirs iron alunite-containing residues and zinc sulfide-containing materials with an oxygen partial pressure of at least 1000 kPa and a temperature condition of 130 to 170 ° C. with 40 to 100 g / l of free sulfuric acid in an autoclave, Substantially dissolve the iron and zinc content of the residue and zinc sulfide-containing concentrate, introduce the solution into a leaching circuit for zinc electrolysis to precipitate iron in the form of hematite, and remove sulfur from the solids. Separating and supplying the residue to another application.
However, this method requires an expensive new device such as an autoclave, which increases the equipment cost, and also has a problem in terms of productivity.

Therefore, it has been proposed to use magnesium oxide contained in the ore itself as a neutralizing agent.
For example, U.S. Patent No. 6,057,053 provides a process for recovering magnesium oxide from a source of magnesium sulfate, which provides a source of magnesium sulfate in solution obtained from a portion of the process associated with the leaching of metal-containing ores or concentrates. A step of converting magnesium sulfate in a solution state to solid magnesium sulfate, a step of contacting solid magnesium sulfate with elemental sulfur in a reducing atmosphere, magnesium as magnesium oxide, and sulfur as sulfur dioxide gas And a recovering step.

By using this method, the magnesium contained in the ore can be reused as a neutralizing agent, and the calcium brought in can be suppressed. As a result, the calcium mixed in the iron oxide in the residue can be reduced. .
However, the method of Patent Document 3 requires a large amount of heat to crystallize magnesium in a solution as magnesium sulfate and to heat the obtained magnesium sulfate to convert it to magnesium oxide, which is an economical method. hard.

Furthermore, a method of using an oxide ore (limonite ore) having a high magnesium content as a neutralizing agent has been proposed.
For example, Patent Document 4 discloses that in a method of recovering nickel or cobalt from an oxide ore containing nickel or cobalt and iron, as the oxide ore, a first oxide ore and a magnesium content ratio than the first oxide ore are disclosed. Preparing a second oxide ore having a high level, classifying the first oxide ore into a first small particle size ore and a first large particle size ore, A classification step of classifying the second small particle size oxide ore and the second large particle size oxide ore, and leaching nickel or cobalt from the first large particle size oxide ore using sulfuric acid, A leaching step of obtaining a sulfuric acid leaching solution containing cobalt and a leaching residue, and mixing the sulfuric acid leaching solution containing the leaching residue with the second large particle size ore, the sulfuric acid leaching solution and the second large particle size oxidized ore React with magnesium contained in The reaction process which adjusts pH, and obtains the reaction liquid containing nickel or cobalt and the reaction residue containing iron, and neutralizes the reaction liquid containing the reaction residue using a neutralizing agent, and contains nickel or cobalt It is a recovery method characterized by including the neutralization liquid and the neutralization process of obtaining the neutralization residue containing iron.

By using this method, nickel oxide ore itself can be used as a neutralizing agent.
However, the cost and effort for classifying the ore could not be ignored. Furthermore, there are many gangue components in the leaching residue, and as it is, the iron quality is low, and it is difficult to say that it is an efficient raw material.
Therefore, it has been difficult to replace the total amount of neutralizing agent used in the HPAL process with magnesium oxide.

In addition, a method for preventing sulfur contamination by replacing the neutralizing agent with magnesium oxide derived from the mother rock can be easily recalled only in the preliminary neutralization step for producing the leach residue.
However, if a conventional calcium-based neutralizing agent is used in the neutralization step and the technique described in Patent Document 1 for improving the efficiency of actual operation is used, the neutralization step residue is returned to the CCD. Therefore, the sulfur content in the leaching residue is unavoidable, and a new problem that causes an increase in sulfur quality occurs.

JP 2004-225120 A Japanese Patent Laid-Open No. 03-176081 JP 2009-520661 A Japanese Patent No. 4294585

  The present invention provides a method for wet refining of nickel oxide ore that makes it possible to use a host rock as a neutralizing agent in the neutralization step of wet refining of nickel oxide ore.

  A first invention of the present invention for solving the above problems is a wet refining method of nickel oxide ore, the wet refining method including a neutralization step, and in the neutralization step, Hematite is concentrated on the small particle size side and the constituents of nickel oxide ore other than the hematite are concentrated on the large particle size side. A nickel oxide ore refining method characterized in that a wet classification step of classifying the obtained neutralization residue is provided following the neutralization step.

  According to a second aspect of the present invention, there is provided a nickel oxide ore refining method characterized in that the host rock in the first invention is a host rock having a particle size not exceeding 500 μm.

  The method for producing hematite for iron production according to the present invention is a conventional method for refining hematite having a low sulfur content to the extent that it can be used as a raw material for iron production from a leach residue containing fine iron oxide produced by the HPAL process. It enables the combined use of a Ca-based neutralizer and a non-Ca-based neutralizer other than a Ca-derived neutralizer. Secondly, it enables sintering of ultrafine ore that has not been conventionally used, and has a remarkable industrial effect.

It is a manufacturing process flowchart of this invention. It is a conventional manufacturing process flowchart.

  The present invention is a method for producing hematite in a production process in which a mineral acid and an oxidizing agent are added to an ore containing iron and valuable metal, and the valuable metal is leached under high temperature and high pressure, and the following (1) to ( 9) A method for producing (high purity) hematite for iron making, which is characterized by undergoing the treatment of 9).

(1) A leaching slurry formed by adding a mineral acid and an oxidizing agent to the ore, and leaching the leachate obtained by leaching valuable metals contained in the ore under high temperature and high pressure by adding a neutralizing agent. Forming high pressure acid leaching process.
(2) A pre-neutralization step in which the obtained leaching slurry is neutralized by addition of a neutralizing agent to form a pre-neutralized slurry that is separated into a Ni-rich component and a Fe-rich component.
(3) The pre-neutralized slurry formed by the pre-neutralization step of (2) is solid-liquid separated into a Ni-enriched slurry (liquid component) and an Fe-enriched slurry (solid component) and washed. Liquid separation step 1.
(4) The neutralization process 1 which neutralizes the Ni enrichment slurry obtained by the solid-liquid separation process 1 of (3) using Ca type | system | group neutralizing agent.
(5) The neutralization process 2 which neutralizes the Fe enrichment slurry obtained by the solid-liquid separation process 1 of (3) using a non-Ca neutralizer.
(6) Solid-liquid separation step 3 in which the neutralized Fe-enriched slurry produced through the neutralization step 2 of (5) is solid-liquid separated and washed to produce hematite as a solid component.
(7) Seed crystal addition in which a part of the Fe-enriched slurry obtained in the solid-liquid separation step 1 of (3) is added as a seed crystal to the neutralization step 1 of (4) to neutralize the Ni-enriched slurry processing.
(8) The solid obtained by solid-liquid separation of the precipitate obtained from the neutralization step 1 of the Ni-enriched slurry of (4) is separated into a residue (solid component) containing a sulfur compound and a liquid component containing no sulfur and washed. Liquid separation step 2.
(9) A firing step of firing the hematite obtained in the solid-liquid separation step 3 of (6) at 1150 to 1350 ° C.

  Furthermore, the water content is removed from the solid component hematite obtained in the solid-liquid separation step 3 in (6), and the moisture content adjustment step (10) in which the water content of the removed hematite is 10% to 17% is performed. Then, it may be fired by the step (9).

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a manufacturing process flow chart of the present invention.
The valuable metal contained in the ore is manufactured according to the flow indicated by the leftmost solid arrow (the thin solid arrow from the neutralization step) in FIG.
On the other hand, hematite, which is a by-product of this manufacturing process, is a leaching residue (Fe rich) obtained at the tip of the solid line arrow branched to the right side from the solid-liquid separation step 1 (CCD) as shown by the thick line in FIG. And then manufactured according to the flow indicated by the rightmost solid line arrow in FIG. Hereinafter, each step will be described in detail.

[Neutralization treatment]
The neutralization treatment in the present invention is performed in three steps of “1. Preliminary neutralization step”, “2. Neutralization step 1”, “3, Neutralization step 2”. The neutralizing agent used in each step is described below.
As the neutralizing agent in the preliminary neutralization step, mother rock, magnesium oxide or magnesium hydroxide is used.
As the neutralizing agent in the neutralizing step 1, a Ca-based neutralizing agent can be used, and inexpensive limestone or slaked lime is used.
As the neutralizing agent in the neutralizing step 2, a non-Ca neutralizing agent is used and sodium hydroxide or potassium hydroxide is used, but magnesium hydroxide or magnesium oxide may be used.
Each neutralization step will be described.

1. Pre-neutralization step In the pre-neutralization step of the present invention, first of all, while using a host rock (unit: wt%) whose representative composition is shown in Table 1 as a neutralizing agent, the mixing of calcium is suppressed. Advance the harmony. In the case of refining nickel oxide ore, the target pH is neutralized to about pH 1 to 3 in order to improve the separation efficiency in the solid-liquid separation step 1 of the next step.

2. Neutralization process 1
In the neutralization process 1 for neutralizing the liquid component (Ni-enriched slurry) obtained from the solid-liquid separation process 1, an inexpensive Ca-based neutralizer such as limestone or slaked lime is used. This enables stable and low-cost operation. In the case of refining nickel oxide ore, the target pH is neutralized to about pH 3 to 5 in order to improve the efficiency of impurity separation in a subsequent process.

The solids that are neutralized and separated in this step are sent to the solid-liquid separation step 2 in a slurry state from the bottom of the neutralization tank, but since gypsum is the main component, it becomes a fine precipitate and settles in the neutralization tank. The speed is small and the solid content of the sediment is not high enough.
Therefore, in order to improve the sedimentation rate, a part of the leaching residue Fe-enriched slurry (haematite is the main component), which is the underflow of the solid-liquid separation step 1 (CCD), is used as a seed crystal, and the solid content weight in the addition is reduced. It is preferable to add in the range of 50% by weight or more and 80% by weight or less of the weight of the precipitate.
If the solid content weight is less than 50% by weight, it does not play a role as a seed crystal, and the sedimentation rate is not sufficiently improved. If it is greater than 80% by weight, the effect of improving the sedimentation rate is not changed so much. This is disadvantageous because the production of hematite obtained by processing the Fe-enriched slurry is reduced.

3. Neutralization process 2
In the neutralization step 2 for neutralizing the leaching residue (Fe-enriched slurry), it is preferable to use sodium hydroxide, potassium hydroxide or the like without using unstable supply of magnesium hydroxide or the like.
Further, using magnesium hydroxide as a neutralizing agent is not preferable because the amount of Mg in the waste water increases and a large amount of neutralizing agent is required in the final Mg solidification treatment.
Since the target pH is the final neutralization step for hematite, it is neutralized to about pH 6-8.

[Solid-liquid separation process]
Next, the solid-liquid separation process in the present invention is performed by three processes of “solid-liquid separation process 1”, “solid-liquid separation process 2”, and “solid-liquid separation process 3”.

1. Solid-liquid separation process 1
The solid-liquid separation step 1 is performed using a known method such as CCD (Counter Current Decantation), and after pre-neutralization separated into Ni-enriched components and Fe-enriched components formed by neutralization in the pre-neutralization step. The slurry is separated into Ni-enriched slurry (liquid component) and Fe-enriched slurry (solid component: leaching residue).

Here, the Ni-enriched slurry is an overflow liquid (supernatant liquid) obtained from the CCD and contains a slight amount of solid content, and is therefore referred to as a slurry for convenience.
The Ni-enriched slurry is processed in a subsequent process to become an intermediate raw material such as a nickel / cobalt mixed sulfide or nickel sulfate solution, and further refined to become a valuable metal.
On the other hand, from the leaching residue of the Fe-enriched slurry, iron oxide for iron making (high purity hematite) is recovered through a neutralization step 2 and a solid-liquid separation step 3 according to the flow indicated by the rightmost solid line arrow in FIG. .

  The solid-liquid separation method used in the solid-liquid separation step 1 includes a substance (here, refers to a slurry after preliminary neutralization), such as a CCD method, in a carrier fluid (here, refers to a cleaning liquid). In addition, the solid-liquid separation method of transporting is preferable from the viewpoint of saving resources because the cleaning liquid created in the manufacturing process can be used, and also preferable from the viewpoint of reducing the sulfur quality in the produced hematite. In the solid-liquid separation step 1, the CCD method is particularly suitable.

2. Solid-liquid separation process 2
In the solid-liquid separation step 2, a known method such as CCD (Counter Current Decantation) is performed, and the liquid component is obtained from the slurry of the precipitate mainly composed of gypsum obtained from the neutralization step 1, and the solid-liquid separation step. 1 is recovered as a cleaning solution, and the residue (solid component) is sent to the final processing step.
By providing this solid-liquid separation step 2, it is possible to use the cleaning liquid from which gypsum has been removed as the cleaning liquid used in the solid-liquid separation step 1 for generating the Fe-enriched slurry. Can be prevented and sulfur quality of the resulting hematite can be suppressed. Also, the amount of newly prepared cleaning liquid can be reduced.

3. Solid-liquid separation process 3
In the solid-liquid separation step 3, a known method such as wet classification, thickener or filter press is used, and the sulfur content is less than 1% as a solid content from the neutralized Fe-enriched slurry obtained from the neutralization step 2. Collect hematite. Further, the obtained liquid component is recovered as a cleaning liquid in the solid-liquid separation step 1.

  In addition, when neutralizing the surplus acid in the leaching slurry using the host rock, after passing through the solid-liquid separation step 1, the leaching residue (hereinafter referred to as neutralization residue for distinction) is treated with a wet cyclone. Etc. is used to concentrate hematite on the small particle size side (for example, wet cyclone overflow; O / F side) of the neutralization residue, and on the large particle size side (wet cyclone in the wet cyclone). It is preferable to enhance the quality of hematite by concentrating substances other than hematite in the underflow (U / F side).

  As described above, in order to improve the operation efficiency in actual operation, the Fe-enriched slurry is added in the neutralization step, and the precipitate that is a residue generated in the neutralization step is returned to the CCD (FIG. 2). In the conventional manufacturing process flow chart of No. 1), only hematite containing about 5 to 8% sulfur could be obtained, but by applying the present invention, hematite having a sulfur content of less than 1% was obtained. It became possible to get.

On the other hand, the hematite cake (denoted as “hematite” in FIG. 1) obtained in the solid-liquid separation step 3 in the production method of the present invention has a low sulfur content of less than 1%, but a relatively high moisture content of 22%. .
In general, when a solid substance is transported, if the water content is high, a liquefaction phenomenon may occur during ship transportation, which may cause the capsizing of the ship. As a result of investigation by the Japan Maritime Examination Association, the transportable moisture value (TML: Transportable Moisture Limit) of the hematite of the present invention was 17% or less. For this reason, when carrying a ship, it is necessary to reduce the moisture content of the cake. At the same time, the particle size of the hematite is as very small as about 1 μm, so the possibility of dust generation is very high.

  Since this dust generation has the property of decreasing as the moisture content increases, the tendency of the fine particles to increase remarkably from 10% when the moisture content is lowered from 17% is 10 to 17%. Is preferred. If dust can be prevented by using a flexible container at the time of handling, the moisture content is preferably lower.

Therefore, a moisture adjustment step for adjusting the moisture content is preferably performed. In the present invention, dehydration is performed to remove moisture from the hematite cake.
As the dehydration method, there are a heating method, a filter press method, a centrifugal separation method, and the like, but a method using a filter press (pressure filtration) is widely used because of its high water removal efficiency and economy.

However, since the obtained hematite is very fine particles, hematite with adjusted water content can be used as a raw material for iron making, but if it remains as fine particles, clogging is likely to occur in a blast furnace, so only a small amount should be used. I can't.
Therefore, the hematite cake obtained from the hematite production process of the present invention, which is very fine particles, is baked to obtain coarse particles.

The hematite obtained by the production method of the present invention has an average particle size of 1 μm or less. If hematite having this particle size is used as a raw material for iron making, clogging will occur at the time of introduction into the blast furnace. Since hematite is composed of ultrafine particles having an average particle size of 1 μm or less, it can be easily sintered, and lime as a sintering aid that has been added at the time of conventional firing is unnecessary.
Therefore, when the average particle diameter of the obtained hematite exceeds 1 μm, the strength of the fired body obtained after firing such hematite is lowered, which is not preferable.

The firing of the hematite can be easily performed at a temperature of 1150 to 1350 ° C. without adding a sintering aid such as lime, and the density of the obtained hematite fired body is 4.0 g / cc to 5.0 g / cc.
When the hematite firing temperature is less than 1150 ° C., the density of the hematite fired body is less than 4.0 g / cc. When the density is 4.0 g / cc or less, the number of pores in the fired body increases, causing cracks in the fired body and causing brittleness.

  On the other hand, when the firing temperature is higher than 1350 ° C., the density exceeds 5.0 g / cc. When the density exceeds 5.0 g / cc, it is difficult for the reducing gas to enter the fired body, and the reduction efficiency of the reducing gas is deteriorated.

  Note that most of the sulfur remaining in the hematite cake is not sulfur derived from gypsum, but is considered to be sulfur of the sulfuric acid component incorporated into the hematite particles in the process of high-temperature pressure acid leaching. By applying this, it is possible to remove substantially all of the sulfur derived from gypsum.

Next, after firing, the particle diameter (d50) is 3 to 20 mm through a pulverization step.
If the particle diameter (d50) is less than 3 mm, it will cause clogging in the blast furnace, and the flow of the reducing gas will deteriorate. On the other hand, when it exceeds 20 mm, reaction time will become long and will cause productivity deterioration.

Moreover, it is preferable to adjust the particle size of the host rock used for the preliminary neutralization treatment to the optimum range by pulverization or the like.
Specifically, as long as the particle size of the host rock does not exceed 500 μm, there is no difference in neutralization performance, and when using a wet cyclone for classification, classification accuracy increases as the particle size of the substance to be classified and removed increases. Therefore, by adjusting the range of the host rock particle diameter to be 500 μm or less and considering the equipment load, it is preferable to adjust the average particle diameter to around 150 μm so that gangues other than hematite can be removed. / F can be distributed to improve the quality of hematite.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The conditions common to the examples and comparative examples are shown in Table 2 below.

The moisture content was measured with a heat drying moisture meter “ML-50” (manufactured by A & D Co., Ltd.), and the sulfur quality was measured using a carbon / sulfur analyzer.
The particle size was measured with a particle size distribution measuring apparatus “model number SALD-3100” (manufactured by SHIMADZU).
A hearth raising / lowering high temperature furnace (manufactured by Marusho Denki Co., Ltd.) was used as the sintering furnace. The sintering temperature was measured by measuring the temperature of the sintered product with a thermocouple, and held for a predetermined time after the sintering temperature reached a predetermined temperature.

In accordance with the manufacturing process flow according to the present invention shown in FIG. 1, the solid-liquid separation process 2 (CCD), the solid-liquid separation process 3 (filter press), and the neutralization process 2 (neutralizing agent: sodium hydroxide) are carried out. The operation was carried out without returning the precipitate obtained from the neutralization step 1 to the solid-liquid separation step 1.
As a result, hematite having a hematite sulfur grade of 0.9%, an average particle size of 0.6 μm, and a moisture content of 22% could be obtained.
Since the Fe-enriched slurry was added to the neutralization step 1 and the sedimentation of the precipitate was promoted, it was possible to operate with the same efficiency as before.

  The obtained hematite cake (10 cm × 20 cm × 1 cm) was baked at 1350 ° C. for 10 minutes. Next, it was pulverized using a jaw crusher.

  The obtained fired body had a sulfur quality of 0.01% and a moisture content of 0%. Moreover, the density of this sintered body was 5.0 g / cc, and the particle diameter (d50) was 3 mm.

In accordance with the manufacturing process flow according to the present invention shown in FIG. 1, the solid-liquid separation process 2 (CCD), the solid-liquid separation process 3 (filter press), and the neutralization process 2 (neutralizing agent: sodium hydroxide) are carried out. The operation was carried out without returning the precipitate obtained from the neutralization step 1 to the solid-liquid separation step 1.
The obtained hematite cake was subjected to a high-pressure filter press (high-pressure heat filtration device) to obtain hematite having a hematite sulfur grade of 0.9%, an average particle size of hematite of 0.6 μm, and a moisture content of 13%.

The obtained hematite cake (10 cm × 20 cm × 1 cm) was baked at 1350 ° C. for 10 minutes. Next, it was pulverized using a jaw crusher.
The obtained fired body had a sulfur quality of 0.01% and a moisture content of 0%. Moreover, the density of this sintered body was 5.0 g / cc, and the particle diameter (d50) was 20 mm.

  In accordance with the manufacturing process flow according to the present invention shown in FIG. 1, the solid-liquid separation process 2 (CCD), the solid-liquid separation process 3 (filter press), and the neutralization process 2 (neutralizing agent: sodium hydroxide) are carried out. The operation was carried out without returning the precipitate obtained from the neutralization step 1 to the solid-liquid separation step 1. The average particle of the obtained hematite was 0.6 μm.

The resulting hematite cake was subjected to a high-pressure filter press (high-pressure heating filtration device) to obtain hematite having a hematite sulfur grade of 0.9% and a moisture content of 13%.
The obtained hematite cake (10 cm × 20 cm × 1 cm) was baked at 1150 ° C. for 10 minutes. Next, it was pulverized using a jaw crusher.
The obtained fired body had a sulfur quality of 0.07% and a moisture content of 0%. Moreover, the density of this sintered body was 4.3 g / cc, and the particle diameter (d50) was 20 mm.

(Comparative Example 1)
Without applying the present invention, as shown in the flow chart of the conventional manufacturing process in FIG. 2, an operation was performed in which the precipitate obtained from the neutralization process was returned to the CCD (solid-liquid separation process).
As a result, the obtained hematite had a sulfur grade of 6.5%, and only hematite that was difficult to use as a raw material for iron making was obtained.

(Comparative Example 2)
In accordance with the manufacturing process flow according to the present invention shown in FIG. 1, the solid-liquid separation process 2 (CCD), the solid-liquid separation process 3 (filter press), and the neutralization process 2 (neutralizing agent: sodium hydroxide) are carried out. The operation was carried out without returning the precipitate obtained from the neutralization step 1 to the solid-liquid separation step 1.
The obtained hematite had a sulfur grade of 0.9%, an average particle size of 0.6 μm, and a moisture content of 22%.

The obtained hematite cake (10 cm × 20 cm × 1 cm) was baked at 1400 ° C. for 10 minutes. Next, it was pulverized using a jaw crusher.
The obtained fired body had a sulfur quality of 0.01% and a moisture content of 0%. Moreover, the density of the sintered body was 5.2 g / cc, and the particle diameter (d50) was 20 mm.

(Comparative Example 3)
In accordance with the manufacturing process flow according to the present invention shown in FIG. 1, the solid-liquid separation process 2 (CCD), the solid-liquid separation process 3 (filter press), and the neutralization process 2 (neutralizing agent: sodium hydroxide) are carried out. The operation was carried out without returning the precipitate obtained from the neutralization step 1 to the solid-liquid separation step 1.
The obtained hematite had a sulfur grade of 0.9%, an average particle size of 0.6 μm, and a moisture content of 22%.

The obtained hematite cake (10 cm × 20 cm × 1 cm) was baked at 1050 ° C. for 10 minutes. Next, it was pulverized using a jaw crusher.
The obtained fired body had a sulfur quality of 0.2% and a moisture content of 0%. The density of the fired body was 3.8 g / cc, and the particle diameter (d50) was 20 mm.

Claims (2)

A method for wet refining of nickel oxide ore,
The wet refining method includes a neutralization step,
In the neutralization step, a host rock is used as a neutralizing agent,
The neutralization residue in which hematite is concentrated on the small particle size side and the constituents of nickel oxide ore other than the hematite are concentrated on the large particle size side by adjusting the particle size of the host rock and performing neutralization Get
The nickel oxide ore refining method, wherein a wet classification step of classifying the neutralization residue is provided following the neutralization step.   2. The nickel oxide ore refining method according to claim 1, wherein the host rock is a host rock having a particle size not exceeding 500 [mu] m.

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