JP2020050905A - Smelting method of oxide ore - Google Patents

Abstract

To provide a smelting method of oxide ore for improving the quality of a metal to be obtained and efficiently producing a metal having high quality in a smelting method for producing metal by reducing a mixture containing oxide ore such as nickel oxide ore.SOLUTION: The smelting method of oxide ore includes: a pulverization and mixing step of supplying lumpy oxide ore and a lumpy carbonaceous reducing agent to a same grinding device, and pulverizing the lumpy materials to obtain a mixture; and a reducing step of subjecting the mixture to a reduction treatment to obtain a reduced product containing a metal and slag.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for smelting an oxide ore, for example, a method for smelting an oxide ore such as a nickel oxide ore as a raw material with a carbonaceous reducing agent to obtain a reduced product.

  As a method for smelting nickel oxide ore called limonite or saprolite, which is a kind of oxide ore, a dry smelting method using a smelting furnace to produce nickel matte, and iron and nickel using a rotary kiln or moving hearth furnace Smelting method (hereinafter referred to as “ferronickel” as an alloy of iron and nickel), acid leaching at high temperature and pressure using an autoclave, and mixed sulfide mixed with nickel and cobalt (mixed sulfide) ) Is known.

  Among the various methods described above, particularly when reducing and smelting nickel oxide ore using a dry smelting method, the nickel oxide ore as a raw material is crushed to an appropriate size in order to advance the reaction. Agglomeration processing is performed as preprocessing.

  Specifically, when the nickel oxide ore is agglomerated, that is, when the powdered or fine ore is agglomerated, the nickel oxide ore is mixed with other components, for example, a reducing agent such as a binder or coke. The mixture is then adjusted for water content, and then charged into a lump manufacturing machine, for example, a molded product (pellet, briquette, or the like having a side or diameter of about 10 mm or more and 30 mm or less; hereinafter, simply referred to as “pellet”. It is common to say).

  The pellets obtained by agglomeration need to have a certain degree of air permeability in order to "blow off" the contained water. Further, if the reduction does not proceed uniformly in the pellets in the subsequent reduction treatment, the composition of the obtained reduced product becomes non-uniform, which causes inconveniences such as dispersion or uneven distribution of the metal. Therefore, it is important to uniformly mix the mixture when preparing pellets and to maintain the temperature as uniform as possible when reducing the obtained pellets.

  In addition, it is a very important technique to coarsen the metal (ferronickel) generated by the reduction treatment. When the produced ferronickel has a fine size of, for example, several tens μm or more and several hundreds μm or less, it is difficult to separate the slag from the simultaneously generated slag, and the recovery rate (yield) as ferronickel is greatly reduced. I will. Therefore, a treatment for coarsening the reduced ferronickel is required.

  For example, in Patent Document 1, an agglomerate containing a metal oxide and a carbonaceous reducing agent is supplied onto a hearth of a moving bed type reduction melting furnace and heated to reduce and melt the metal oxide. In the manufacturing method, the relative value of the projected area ratio of the agglomerate to the hearth with respect to the maximum projected area ratio of the agglomerate to the hearth when the distance between the agglomerates is 0 is defined as the floor density. A method is disclosed in which agglomerates having an average diameter of 19.5 mm or more and 32 mm or less are supplied onto a hearth so as to have a bed density of 0.5 or more and 0.8 or less, and are heated. In this method, it is described that the productivity of granular metallic iron can be increased by controlling the bed density and the average diameter of the agglomerate together.

  However, in the method using a material having a specific diameter as an agglomerate as disclosed in Patent Literature 1, it is necessary to remove a material having no specific diameter. There was a problem of low. Further, in the method of Patent Document 1, it is necessary to adjust the bed density of the agglomerate to 0.5 or more and 0.8 or less, and it is not possible to laminate the agglomerate. Was high.

  As described above, the technology of producing a metal or an alloy by mixing and reducing an oxide ore has many problems in terms of increasing productivity, reducing production cost, and improving metal quality.

JP 2011-256414 A

  The present invention provides a smelting method for producing a metal by reducing a mixture containing an oxide ore such as a nickel oxide ore, which can improve the quality of the obtained metal and efficiently produce a high-quality metal. It is an object of the present invention to provide a method for smelting an oxide ore that can be performed.

  The present inventor has found that the above problem can be solved by supplying a lump of oxide ore and a lump of carbonaceous reducing agent to the same grinding apparatus to obtain a mixture and grinding the mixture, The present invention has been completed.

  (1) A first aspect of the present invention is to supply a lump of oxide ore and a lump of carbonaceous reducing agent to the same pulverizer, and to pulverize the lump to obtain a mixture, Performing a reduction treatment on the obtained mixture to obtain a reduced product containing metal and slag.

  (2) A second aspect of the present invention is the method for refining an oxide ore according to the first aspect, wherein the crushing device is any one of a jaw crusher, a roll mill, a hammer crusher, a roll crusher, and a double roll crusher. .

  (3) A third aspect of the present invention is the method for refining an oxide ore according to the first or second aspect, in which the obtained mixture is kneaded in the pulverizing and mixing step.

  (4) A fourth aspect of the present invention is the method for refining an oxide ore in which the oxide ore is a nickel oxide ore according to any one of the first to fourth inventions.

  ADVANTAGE OF THE INVENTION According to the smelting method of the oxide ore which concerns on this invention, a high quality metal can be manufactured efficiently.

It is a flowchart showing an example of a flow of a smelting method of nickel oxide ore. It is a figure which shows typically the state when each lump used for a grinding process is ground together with the same jaw crusher.

  Hereinafter, specific embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments, and various changes can be made without changing the gist of the present invention. In this specification, the notation “X to Y” (X and Y are arbitrary numerical values) means “X or more and Y or less”.

≪1. Outline of smelting method of oxide ore
In the method for smelting oxide ore according to the present embodiment, oxide ore (oxide) as a raw material ore is mixed with a carbonaceous reducing agent, and the mixture (pellet) is mixed in a smelting furnace (reduction furnace). By performing the reduction treatment, metal and slag are generated.

  For example, as the oxide ore, a nickel oxide ore containing nickel oxide, iron oxide, or the like is used as a raw material, and the nickel oxide ore and a carbonaceous reducing agent are mixed to form a molded product. There is a method of producing ferronickel, which is an alloy of iron and nickel, by reducing preferentially and partially reducing iron.

  In the smelting method of the oxide ore according to the present embodiment, when preparing a mixture containing the oxide ore and the carbonaceous reducing agent, the lump of the oxide ore and the aggregate of the carbonaceous reducing agent are mixed in the same pulverizing apparatus. And the masses are ground together to obtain a mixture.

  According to such a method, the particle size and particle size distribution of the oxide ore and the carbonaceous reducing agent, which are the raw material components in the mixture to be subjected to the reduction treatment, can be made substantially equal. By subjecting such a mixture to a reduction treatment, the reduction reaction easily proceeds uniformly in the mixture, and the quality of the obtained metal can be improved.

{2. Smelting method for producing ferronickel using nickel oxide ore.
In the following, the nickel (nickel oxide) and iron (iron oxide) contained in the nickel oxide ore, which is the raw material ore, are reduced to generate a metal of the iron-nickel alloy, and the metal is separated to separate the ferromagnetic alloy. A smelting method for producing nickel will be described as an example.

  Specifically, as shown in FIG. 1, the nickel oxide ore smelting method according to the present embodiment is a method of pulverizing and mixing a nickel oxide ore as a raw material component and a carbonaceous reducing agent to obtain a mixture. The method includes a step S1, a reduction step S2 of performing a reduction treatment on the obtained mixture to obtain a reduced product containing metal and slag, and a separation step S3 of separating metal and slag from the reduced product.

<2-1. Grinding and mixing process>
The pulverization mixing step S1 is a step of pulverizing and mixing the nickel oxide ore and the carbonaceous reducing agent, which are the raw material components, to obtain a mixture. In addition, a mixture is obtained by adding iron ore, a flux component, a binder, and the like as optional additives. The mixture obtained through the pulverizing / mixing step S1 is subjected to the processing (reduction processing) in the reduction step S2 of the next step.

The nickel oxide ore, which is a raw material ore, is not particularly limited, and limonite ore, saprolite ore, or the like can be used. Note that the nickel oxide ore contains at least nickel oxide (NiO) and iron oxide (Fe ₂ O ₃ ).

  Although it does not specifically limit as a carbonaceous reducing agent, For example, coal powder, coke powder, etc. are mentioned.

  As the content of the carbonaceous reducing agent (the content of the carbonaceous reducing agent contained in the mixture), the chemical equivalent required to reduce the total amount of nickel oxide constituting the nickel oxide ore to nickel metal and the iron oxide ( 50.0% by mass when the total value of the chemical equivalents required to reduce ferric oxide to metallic iron (also referred to as “the sum of the chemical equivalents” for convenience) is 100% by mass. The ratio is preferably set to the following ratio, more preferably 40.0% by mass or less. The amount of iron reduction can be suppressed, the nickel quality can be increased, and high quality ferronickel can be manufactured. Further, the mixing amount of the carbonaceous reducing agent is preferably at least 10.0% by mass when the total value of the chemical equivalents is 100% by mass, and more preferably at least 15.0% by mass. Is more preferable. The reduction of nickel can proceed efficiently and productivity can be improved.

  As the iron ore as an optional additive, for example, iron ore having an iron grade of about 50.0% by mass or more, hematite obtained by hydrometallurgy of nickel oxide ore, or the like can be used. Examples of the flux component include calcium oxide, calcium hydroxide, calcium carbonate, and silicon dioxide. Examples of the binder include bentonite, polysaccharide, resin, water glass, dehydrated cake, and the like.

  Table 1 below shows an example of the composition (% by mass) of some raw material powders to be mixed in the pulverizing and mixing step S1, but the composition of the raw material powders is not limited to this.

  By the way, in the conventional smelting method of oxide ore, for example, each component such as nickel oxide ore and carbonaceous reducing agent is separately pulverized into powder having a predetermined particle size, and the obtained powdery components Was generally mixed to form a mixture. However, in preparing the mixture, even when the lump of nickel oxide ore and the lump of carbonaceous reducing agent are each pulverized under the same conditions, the particle size and particle size distribution of each powdery component obtained are Large differences often occurred. If there is a difference in particle size or particle size distribution between the nickel oxide ore powder and the carbonaceous reducing agent powder that make up the mixture, voids are formed between the particles when they are mixed to form a mixture. Will be done. Then, when such a mixture is subjected to a reduction treatment, the reduction reaction in the mixture does not proceed uniformly, causing variations, and as a result, a low-quality metal is produced.

  Therefore, in the method for smelting nickel oxide ore according to the present embodiment, a lump of nickel oxide ore and a lump of carbonaceous reducing agent are supplied to the same pulverizing device, and these lump are pulverized together. It is characterized by: Here, the “mass” is a form before pulverization of the nickel oxide ore or the carbonaceous reducing agent, and is a form before mixing each component to become a powder component constituting the mixture. . In addition, what was coarsely pulverized is included in the concept of a lump.

  According to such a method, a powder of nickel oxide ore and a powder of a carbonaceous reducing agent having substantially the same particle size and particle size distribution can be obtained in the pulverizer, and such a particle size can be obtained from a substantially uniform component. The resulting mixture can be prepared. Then, by subjecting the mixture thus prepared to a reduction treatment, a reduction reaction in the mixture can be uniformly generated, and the quality of the metal obtained through the reduction treatment can be increased, thereby achieving high quality. It is possible to manufacture a simple metal.

  FIG. 2 is a diagram schematically illustrating a state in which a mixture of each lump is crushed by a jaw crusher. FIG. 2 shows a partial configuration of the jaw crusher. The jaw crusher is a crushing device that crushes an object by two metal blade plates. Specifically, one fixed blade plate 11 is fixed, and another vibration blade plate 12 is swung, and a lump is supplied between the two blade plates 11 and 12 to crush the target.

Specifically, in the grinding and mixing step S1, first, a lump a of nickel oxide ore and a lump b of carbonaceous reducing agent having a predetermined size are prepared. If the size of the lump is too large, it may be difficult to supply it to the pulverizer and pulverize it properly. For example, a large nickel oxide ore or carbonaceous reducing agent of 1000 cm ³ or more is coarsely pulverized. It is preferred to obtain a lump. For example, the diameter of the lump is preferably about 0.5 cm or more and about 20 cm or less, and more preferably about 0.5 cm or more and about 15 cm or less. By supplying a lump having a diameter of about 0.5 cm to about 20 cm to a pulverizer and pulverizing the same, a mixture having a more uniform particle size and particle size distribution can be obtained.

  Next, as shown in FIG. 2, a lump a of nickel oxide ore and a lump b of carbonaceous reducing agent are supplied to a jaw crusher. At this time, iron ore, a flux component, and the like may be supplied together as optional additives and may be ground together.

  Then, in the jaw crusher, the lump a of nickel oxide ore and the lump b of the carbonaceous reducing agent are simultaneously pulverized to obtain a powder having substantially the same particle size and particle size distribution.

  Here, when a lump of nickel oxide ore and a lump of carbonaceous reducing agent are pulverized together with a pulverizing device such as a jaw crusher, each of the powdery components obtained as a result of the pulverization in the pulverizing device. It is in a mixed state. Therefore, the powder discharged from the pulverizer is a mixture in which the nickel oxide ore and the carbonaceous reducing agent are uniformly mixed (“mixture C” shown in FIG. 2).

  However, it does not exclude that after the pulverization by the pulverizing device, the powder taken out from the pulverizing device is separately mixed using a mixer or the like. After pulverization by a pulverizer, the obtained powder is charged into a mixer or the like and mixed to mix the nickel oxide ore and the carbonaceous reducing agent in a more uniform powder state to prepare a mixture. Can be. Even in such a case, since the lump of the nickel oxide ore and the lump of the carbonaceous reducing agent are simultaneously pulverized using the same pulverizer, the particle size and the particle size distribution are substantially the same. All the powders are mixed by a mixer or the like.

  The pulverizer is not limited to the jaw crusher illustrated with reference to FIG. Specifically, in addition to the jaw crusher, one selected from a roll mill, a hammer crusher, a roll crusher, a double roll crusher, and the like can be used.

  The mixture obtained as described above may be further kneaded. By kneading the mixture containing the raw material powder, a pressure (shearing force) can be applied to the mixture, and the state in which the aggregation of the carbonaceous reducing agent, the raw material powder, and the like is released and the mixture is more uniformly mixed is obtained. can do. Further, by performing kneading, voids formed between particles of the mixture can be further reduced.

  The kneading can be performed using a batch type kneader such as Brabender, a Banbury mixer, a Henschel mixer, a helical rotor, a roll, a single-screw kneader, a twin-screw kneader, or the like.

  After kneading, the mixture may be extruded using an extruder. As a result, a pressure (shearing force) is applied to the mixture, and the aggregation of the carbonaceous reducing agent, the raw material powder, and the like is released, and the mixture can be more uniformly mixed. Furthermore, voids in the mixture can be reduced. From these facts, the reduction reaction of the mixture tends to occur uniformly in the reduction step S2 described later, the quality of the obtained metal can be improved, and a high-quality metal can be manufactured.

  The extruder is preferably one capable of kneading and molding the mixture under high pressure and high shear force, and examples thereof include a single screw extruder and a twin screw extruder. In particular, it is preferable to provide a twin-screw extruder. By kneading the mixture under high pressure and high shear, the mixture of the raw material powders can be deagglomerated, and can be effectively kneaded, and the strength of the mixture can be increased. In addition, by using a twin-screw extruder, a mixture can be obtained while maintaining high productivity continuously.

  Further, the mixture may be formed into a molded product (pellet) having a predetermined shape. The shape of the molded product can be, for example, spherical, rectangular, cubic, cylindrical, or the like. Since such a shape is a simple shape and not complicated, it is possible to suppress the occurrence of defective products while suppressing the molding cost, the quality of the obtained molded product is also uniform, and the reduction in yield is suppressed. can do.

  The shape of the molded product is particularly preferably spherical. By being a spherical molded product, the reduction treatment can be performed uniformly, and smelting with little variation and high productivity can be performed. When the shape of the molded product is spherical, it can be molded so that the diameter is about 10 mm or more and about 30 mm or less. In the case of a rectangular parallelepiped shape, a cubic shape, a columnar shape, or the like, it can be formed so that the vertical and horizontal inner dimensions are approximately 500 mm or less.

The size of the molded product is not particularly limited, but the volume of the molded product is preferably 8000 mm ³ or more. When the volume of the molded product is 8000 mm ³ or more, the molding cost is suppressed, and the ratio of the surface area to the entire molded product is reduced. Therefore, the reduction treatment is uniformly performed, the variation is small, and the productivity is low. High smelting can be performed.

  Further, the crushed mixture may be filled in a predetermined reducing container. By performing the reduction treatment in a state where the mixture filled in the container is filled in the container, the metal reduced in the separation step S3 to be described later can easily separate and recover the metal by a process such as magnetic separation, thereby reducing loss. Can be suppressed.

  In the pulverizing and mixing step S1, a drying treatment for drying the pulverized mixture may be performed. Although it is not an essential aspect to perform the drying treatment in the present embodiment, it is possible to prevent the molded product from expanding due to vaporization of water in the reduction treatment described below.

  The method for drying the mixture is not particularly limited, such as a method of maintaining the mixture at a predetermined drying temperature (for example, 300 ° C. or more and 400 ° C. or less), a method of blowing hot air at a predetermined drying temperature against the mixture, and the like. Conventionally known means can be used. By such a drying treatment, for example, the solid content of the mixture is about 70% by mass and the water content is about 30% by mass. The temperature of the mixture itself during the drying treatment is preferably less than 100 ° C., which is preferable because bursting of the mixture due to bumping of water or the like can be suppressed.

  Further, the drying treatment may be continuously performed at once or may be performed in a plurality of times. Burst of the mixture can be more effectively suppressed by performing the drying treatment in a plurality of times. In the case where the drying treatment is performed a plurality of times, the second and subsequent drying temperatures are preferably 150 ° C. or more and 400 ° C. or less. By drying in this range, drying can be performed without the reduction reaction proceeding.

  Table 2 below shows an example of the composition (parts by mass) in the solid content of the mixture after the drying treatment. The composition of the molded product is not limited to this.

<2-2. Reduction process>
The reduction step S2 is a step of heating the obtained mixture and performing a reduction treatment to obtain a reduced product containing metal and slag. By the heat reduction treatment in the reduction step S2, a smelting reaction (reduction reaction) proceeds, and ferronickel metal (hereinafter, simply referred to as “metal”) and ferronickel slag (hereinafter, simply referred to as “slag”) are separated. Generate.

  Here, in the present embodiment, in the pulverization-mixing step S1, a mixture containing nickel oxide ore and a carbonaceous reducing agent having substantially the same particle size and particle size distribution is prepared. On the other hand, by performing the reduction treatment, the reduction reaction can be uniformly generated, and as a result, the quality of the obtained metal can be increased and a high-quality metal can be manufactured.

  The reduction treatment in the reduction step S2 is performed by charging a mixture containing nickel oxide ore into a reduction furnace heated to a predetermined reduction temperature. In the reduction treatment, the nickel oxide contained in the nickel ore, which is the raw material ore, is reduced as completely and preferentially as possible, while the iron oxide contained in the nickel oxide ore is partially reduced. So-called partial reduction is performed to obtain ferronickel of high nickel quality.

  In the reduction treatment, the nickel oxide ore and iron oxide in the mixture are reduced and metallized to ferronickel in the vicinity of the surface of the mixture where the reduction reaction easily proceeds, for example, in a short period of time, for example, about 1 minute. Form. On the other hand, in the shell, the slag component is gradually melted with the formation of the shell, and slag in a liquid phase is generated. Thereby, the metal and the slag are separately generated in the mixture.

  Then, when the treatment time elapses about 10 minutes, the excess carbonaceous reducing agent not involved in the reduction reaction is taken into the metal to lower the melting point, so that the metal also becomes a liquid phase. In addition, the volume of this reduced product has shrunk to about 50% or more and 60% or less as compared with the mixture charged in the reduction furnace.

  The temperature (reduction temperature) in the reduction treatment is not particularly limited, but is preferably in the range of 1200 ° C to 1450 ° C, more preferably in the range of 1300 ° C to 1400 ° C. By performing reduction in such a temperature range, a reduction reaction can be uniformly generated, and ferronickel with reduced quality variation can be generated. More preferably, by performing the reduction at a reduction temperature in the range of 1300 ° C. or more and 1400 ° C. or less, a desired reduction reaction can be caused in a relatively short time.

  The time in the reduction treatment (treatment time) is set according to the temperature of the reduction furnace, but is preferably 10 minutes or more, and more preferably 15 minutes or more.

  In the reduction treatment, the internal temperature of the reduction furnace may be increased by, for example, a burner until the reduction temperature in the above-described range is reached, and the temperature may be maintained after the temperature increase.

  In addition, it is preferable that the calorie required for the reduction by multiplying the value of the reduction temperature (° C.) by the numerical value of the reduction time (min) is in the range of 20,000 (° C. × min) to 40,000 (° C. × min) or less. Thereby, a high quality metal can be efficiently manufactured.

  The reduction furnace is not particularly limited. A single furnace may be used, or a furnace such as a moving hearth furnace which can be continuously processed in each process by rotating a hearth or the like may be used. Among them, by using a moving hearth furnace as the reduction furnace, the reduction reaction can proceed continuously and the reaction can be completed with one facility. In addition, when the operation is performed using a separate furnace for each process, there is a possibility that a heat loss may occur due to a decrease in temperature when moving between furnaces. Further, a change may occur in the atmospheric gas, and it may not be possible to immediately cause a reaction when the gas is recharged into the furnace. In this regard, using a moving hearth furnace to perform each process in a single facility reduces heat loss and enables accurate control of the furnace atmosphere, allowing the reaction to proceed more effectively. Can be.

  The moving hearth furnace is not particularly limited. For example, a rotary hearth furnace having a circular shape and divided into a plurality of processing regions can be used. In a rotary hearth furnace, each process is performed in each region while rotating in a predetermined direction. In this rotary hearth furnace, the processing temperature in each area can be adjusted by controlling the time (moving time, rotation time) when passing through each area, and the rotary hearth furnace makes one rotation. Each time the mixture is smelted. The moving hearth furnace may be a roller hearth kiln or the like.

  In the reduction treatment, when the mixture obtained from the mixing step S1 is charged into the reduction furnace, a carbonaceous reducing agent (hereinafter, also referred to as "hearth carbonaceous reducing agent") is spread over the hearth in the reduction furnace in advance. Then, the mixture may be placed on the spread hearth carbonaceous reducing agent. Alternatively, a floor covering material mainly composed of an oxide may be laid on the hearth, and the mixture may be placed thereon. In this way, by laying a carbonaceous reducing agent, a floor covering material, and the like on the hearth and placing the mixture thereon, the reaction between the hearth and the mixture can be suppressed. Life can be extended.

  Here, after the above-described reduction treatment, a temperature holding treatment may be performed to hold the obtained reduced product composed of metal and slag at a predetermined temperature, for example, in the same reduction furnace. More specifically, in the temperature holding process, the reduced product obtained by the reduction process is held at a predetermined temperature for a certain time in the same reduction furnace without being taken out of the reduction furnace. As described above, by performing the temperature holding treatment on the reduced product in the same reduction furnace, the metal can be effectively settled in the reduced product in the semi-molten state to promote the separation of the metal phase and the slag phase. it can. As a result, the metal recovery rate can be increased, and higher quality metal can be obtained.

  The atmosphere gas in the reduction furnace after the reduction treatment is mainly a CO gas derived from a carbonaceous reducing agent, which contains a large amount of a reducing gas such as CO, and includes an inert gas and the like. Almost no oxidizing gas. Therefore, in the reduction furnace after the heat-reduction treatment containing almost no oxidizing gas such as oxygen, the obtained reduced product is subjected to a predetermined condition in a state accompanied by the atmospheric gas (the reduced product is cut off from the oxidizing atmosphere). By maintaining the temperature at the temperature, it is possible to precipitate the metal in the reduced product while effectively suppressing the oxidation of the metal in the reduced product.

  The processing time of the temperature holding (temperature holding time) is not particularly limited, but is preferably 10 minutes or more and 1000 minutes or less, and more preferably 30 minutes or more and 180 minutes or less.

<2-3. Separation process>
The separation step S3 is a step of separating metal and slag from the obtained reduced product. Specifically, the metal phase is separated and recovered from a mixture (reduced product) containing a metal phase (metal solid phase) and a slag phase (slag solid phase) obtained by reduction heating treatment of the mixture.

  As a method of separating the metal phase and the slag phase from the mixture of the metal phase and the slag phase obtained as a solid, for example, in addition to removing unnecessary substances by sieving, separation by specific gravity, separation by magnetic force, and the like Method can be used.

  In addition, the obtained metal phase and slag phase can be easily separated because of poor wettability, and for large inclusions, for example, a predetermined head is provided for dropping, or when sieving. By giving an impact such as giving a predetermined vibration, the metal phase and the slag phase can be easily separated from the mixture.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Preparation of mixture]
<Example>
The raw material of the nickel oxide ore was subjected to a sieving process using a sieve having a diameter of 5.0 cm to obtain a lump of nickel oxide ore having a diameter of 5.0 cm or less. In addition, by performing a sieving process on a carbonaceous reducing agent (coal powder, carbon content: 85% by mass) using a sieve having a diameter of 2.0 cm, a lump of carbonaceous reducing agent having a diameter of 2.0 cm or less is obtained. I got something.

The lump of the obtained nickel oxide ore and the lump of the carbonaceous reducing agent are supplied to the same pulverizer, and the lump is pulverized together to obtain a mixture of Examples 1 to 11. Was. The amount of the carbonaceous reducing agent (coal powder) required to reduce nickel oxide and iron oxide (Fe ₂ O ₃ ) contained in the nickel oxide ore without excess or deficiency is 27% by mass. It was contained in such an amount as to be a percentage by mass.

<Comparative example>
In the same manner as in the above example, a lump of nickel oxide ore having a diameter of 5.0 cm or less and a lump of carbonaceous reducing agent having a diameter of 2.0 cm or less were obtained, and then supplied to separate pulverizers. The grinding of only the lump of the nickel oxide ore and the grinding of only the lump of the carbonaceous reducing agent were performed. Thus, a powder of nickel oxide ore was obtained from one pulverizer, and a powder of the carbonaceous reducing agent was obtained from another pulverizer.

  Thereafter, the obtained nickel oxide ore powder and the carbonaceous reducing agent powder were charged into a mixer and mixed while adding an appropriate amount of water to obtain mixtures of Comparative Examples 1 to 5.

[Reduction treatment]
The obtained mixtures of Examples 1 to 11 and Comparative Examples 1 to 5 were appropriately added with water to obtain a spherical mixture (sample) having a diameter of 15 ± 0.5 mm using a bread granulator. Each sample was charged in a reduction furnace and subjected to a reduction treatment under the conditions shown in Table 3. In addition, the hearth of the reduction furnace is preliminarily laid with ash (containing SiO _{2 as} a main component and small amounts of oxides such as Al ₂ O ₃ and MgO as other components), and the mixture sample is placed on the ash. I made it.

[Separation processing]
After the reduced product obtained by the reduction treatment was taken out of the reduction furnace and cooled, the samples of Examples 1 to 11 and Comparative Examples 1 to 5 were pulverized, and the metal was recovered by magnetic separation.

  For each sample, the nickel metallization ratio and the nickel content in the metal were calculated by analysis using an ICP emission spectrometer (SHIMAZU S-8100).

The nickel metal conversion rate, the nickel content rate in the metal, and the nickel metal recovery rate were calculated by the following equations (1) and (2).
Nickel metallization rate = mass of nickel in metal ÷ (mass of all nickel in reduced product) × 100 (%) Formula (1) Nickel content in metal = mass of nickel in metal ÷ (metal Total mass of nickel and iron in the material) x 100 (%) ... (2)

  As can be seen from the results in Table 3, in Examples 1 to 11, the nickel metallization ratio, the nickel content in the metal, and the metal recovery ratio were all higher than in Comparative Examples 1 to 5. This is because, in preparing the mixture to be subjected to the reduction treatment, the lump of nickel oxide ore and the lump of carbonaceous reducing agent are supplied to the same grinding device to pulverize the lump together. It is considered that since the mixture was composed of components having substantially the same particle size and particle size distribution, the reduction reaction in the mixture began to occur uniformly.

1 crusher (jaw crusher)
Reference Signs List 11 fixed blade plate 12 vibrating blade plate a lump of oxide ore b lump of carbonaceous reducing agent C mixture

Claims (4)

A crushing and mixing step of supplying the lump of the oxide ore and the lump of the carbonaceous reducing agent to the same crusher, and crushing the lumps to obtain a mixture;
A reduction step of performing a reduction treatment on the obtained mixture to obtain a reduced product containing metal and slag,
For smelting oxide ores containing The smelting method of an oxide ore according to claim 1, wherein the crushing device is any one of a jaw crusher, a roll mill, a hammer crusher, a roll crusher, and a double roll crusher. The smelting method of an oxide ore according to claim 1 or 2, wherein the obtained mixture is kneaded in the pulverizing and mixing step. The method for refining an oxide ore according to any one of claims 1 to 3, wherein the oxide ore is a nickel oxide ore.

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