阅读说明：本技术 锰原料的制造方法及含锰钢的熔炼方法 (Method for producing manganese raw material and method for smelting manganese-containing steel ) 是由 小田信彦 日野雄太 高木勇辉 西名庆晃 菊池直树 于 2019-02-22 设计创作，主要内容包括：本发明提供通过从含锰氧化物物质中回收杂质浓度低的锰原料从而能够降低含锰铁水的熔炼成本的锰原料的制造方法及含锰钢的熔炼方法。所述锰原料的制造方法具备：第一粉碎工序(S100),以含锰氧化物物质作为原料,通过对所述含锰氧化物物质进行粉碎所产生的压缩力而生成复合物,从而生成含有复合物的第一粉碎含锰氧化物物质,所述含锰氧化物物质至少包含锰、钙、硅、铁及磷,所述复合物是作为强磁体的尖晶石相及铁酸钙相中的至少一相与nCaO·P<Sub>2</Sub>O<Sub>5</Sub>化合物相复合而成的；第一磁选工序(S102),通过磁力将粉碎工序中生成的第一粉碎含锰氧化物物质分离成磁化物和非磁化物；将第一磁选工序中分离出的非磁化物作为锰原料而回收的工序(S104)。(The invention provides a method for producing a manganese raw material and a method for smelting manganese-containing steel, which can reduce the smelting cost of manganese-containing molten iron by recovering a manganese raw material with low impurity concentration from a manganese-containing oxide substance. The method for producing a manganese raw material comprises: a first grinding step (S100) for forming a first ground manganese-containing oxide substance containing at least manganese, calcium, silicon, iron and phosphorus by using a manganese-containing oxide substance as a raw material and generating a composite by means of a compressive force generated by grinding the manganese-containing oxide substance, wherein the composite is formed by at least one phase of a spinel phase and a calcium ferrite phase which are ferromagnetic bodies and nCaO & P 2 O 5 Compound phase composition; a first magnetic separation step (S102) for magnetically separating the first pulverized manganese-containing oxide substance produced in the pulverization step into a magnetized substance and a non-magnetized substance; and a step (S104) for recovering the non-magnetized material separated in the first magnetic separation step as a manganese raw material.)

1. A method of producing a manganese feedstock, the method comprising:

a first pulverization step of generating a first pulverized manganese-containing oxide substance containing at least manganese, calcium, silicon, iron, and phosphorus by generating a complex by using a manganese-containing oxide substance as a raw material and by generating a compressive force generated by pulverizing the manganese-containing oxide substance, wherein the complex is at least one of a spinel phase and a calcium ferrite phase which are ferromagnetic bodies and nCaO & P₂O₅Compound phase composition;

a first magnetic separation step of magnetically separating the first pulverized manganese-containing oxide substance produced in the first pulverization step into a magnetized substance and a non-magnetized substance;

and a step of recovering the non-magnetized material separated in the first magnetic separation step as a manganese raw material.

2. The method for producing a manganese raw material according to claim 1,

in the first pulverization step, the first pulverized manganese-containing oxide substance is pulverized so that the particle diameter thereof is 500 μm or less.

3. The method for producing a manganese raw material according to claim 1 or 2,

in the first pulverization step, a substance containing a manganese silicate phase as a mineral phase is used as the manganese oxide-containing substance.

4. The method for producing a manganese raw material according to claim 3,

in the first magnetic separation step, the manganese silicate phase is separated as a non-magnetized substance by separation using a magnetic force that does not magnetize the manganese silicate phase.

5. The method for producing a manganese raw material according to any one of claims 1 to 4,

in the first magnetic separation step, the magnetic field to be applied is a fluctuating magnetic field that changes with time.

6. The method for producing a manganese raw material according to any one of claims 1 to 5, further comprising:

a classifying step of classifying the first pulverized manganese-containing oxide substance into coarse particles and fine particles with a separation particle size set to a range of 30 μm to 150 μm after the first pulverizing step,

in the first magnetic separation step, the coarse particles obtained by classification in the classification step are separated.

7. The method for producing a manganese raw material according to claim 6, further comprising:

a third magnetic separation step of separating the fine particles obtained by the classification step into a magnetized material and a non-magnetized material by a magnetic force;

and a step of recovering the magnetized material separated in the third magnetic separation step as a manganese raw material.

8. The method for producing a manganese raw material according to any one of claims 1 to 7, further comprising:

a second pulverization step of pulverizing the magnetic material separated in the first magnetic separation step to produce a second pulverized manganese-containing oxide substance;

a second magnetic separation step of magnetically separating the second pulverized manganese-containing oxide substance produced in the second pulverization step into a magnetized substance and a non-magnetized substance;

and a step of recovering the magnetized material separated in the second magnetic separation step as a manganese raw material.

9. A method of smelting manganese-containing steel, the method comprising:

a method for producing a manganese raw material according to any one of claims 1 to 8, wherein a manganese raw material recovered by the method is added to molten iron or molten steel, and the manganese concentration of the molten iron or molten steel is adjusted.

Technical Field

The present invention relates to a method for producing a manganese raw material and a method for smelting manganese-containing steel.

Background

In response to the recent demand for weight reduction of vehicle bodies of automobiles and the like, there has been an increasing demand for high-tensile steel sheets called high-strength steel materials. Such a high-strength steel material is generally provided with high tensile strength by adding a metal such as manganese (Mn).

Examples of the raw material mainly used as the manganese raw material include manganese-containing oxide materials typified by manganese ore, ferromanganese, and metal manganese. The cost (unit price) of unit pure manganese is reduced in sequence according to the sequence of manganese ore, ferromanganese and metal manganese. Therefore, by selecting a manganese-containing oxide substance typified by manganese ore as a manganese raw material, cost reduction can be achieved.

However, manganese ores and ferromanganese, which are generally inexpensive manganese raw materials, contain a large amount of impurities represented by carbon (C) and phosphorus (P), and particularly contain about 0.02 to 0.2 mass% of P. Therefore, when molten iron containing manganese or molten steel containing manganese (molten iron and molten steel are collectively referred to as "molten iron") is smelted using an inexpensive manganese raw material, P contained in the manganese raw material is transferred to the molten iron containing manganese, and thus it is necessary to subject the molten iron containing manganese to dephosphorization.

As a method for dephosphorizing molten iron having a high manganese content, for example, a method described in patent document 1 is known.

Disclosure of Invention

Problems to be solved by the invention

In the method described in patent document 1, BaO or BaCO is used₃、Ba(OH)₂、BaSO₄、BaCl₂、BaF₂And the like, containing Ba. However, the generated BaO is specified as a harmful substance in japan, and its disposal is restricted by law. Therefore, the method of patent document 1 using the flux containing Ba has a great problem in slag treatment and the like.

The usable amount of the manganese-containing oxide material or the low-cost manganese raw material such as ferromanganese in the production of molten iron containing manganese depends on the P standard (upper limit concentration of P) of the product. Therefore, when high manganese steel having a manganese content of 3 mass% or more is to be smelted, the proportion of manganese metal having a low P concentration and a high cost as a manganese raw material has to be increased, which causes a problem of extremely high smelting cost.

The present invention has been made in view of the above problems, and an object thereof is to provide a method for producing a manganese raw material and a method for smelting manganese-containing steel, which can reduce the smelting cost of molten manganese-containing iron by recovering a manganese raw material having a low impurity concentration from a manganese-containing oxide substance.

Means for solving the problems

According to one embodiment of the present invention, there is provided a method for producing a manganese raw material, including: a first pulverization step of generating a first pulverized manganese-containing oxide substance containing at least manganese, calcium, silicon, iron, and phosphorus by generating a complex by using a manganese-containing oxide substance as a raw material and by generating a compressive force generated by pulverizing the manganese-containing oxide substance, wherein the complex is at least one of a spinel phase and a calcium ferrite phase which are ferromagnetic bodies and nCaO & P₂O₅Compound phase composition; a first magnetic separation step of subjecting the first pulverized manganese oxide-containing substance produced in the first pulverization step to magnetic separationSeparating into a magnetized substance and a non-magnetized substance; and a step of recovering the non-magnetized material separated in the first magnetic separation step as a manganese raw material.

According to an aspect of the present invention, there is provided a method for smelting manganese-containing steel, including: the method for manufacturing a manganese raw material includes adding a manganese raw material recovered by the method for manufacturing a manganese raw material to molten iron or steel to adjust a manganese concentration of the molten iron or steel.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided a method for producing a manganese raw material and a method for smelting a manganese-containing steel, which can reduce the smelting cost of molten manganese-containing iron by recovering a manganese raw material having a low impurity concentration from a manganese-containing oxide substance such as manganese ore,

drawings

Fig. 1 is a flowchart illustrating a method for producing a manganese raw material according to a first embodiment of the present invention.

Fig. 2 is a schematic diagram showing the mechanism of the method for producing a manganese raw material according to the first embodiment of the present invention.

Fig. 3 is a flowchart showing a method for producing a manganese raw material according to a second embodiment of the present invention.

Fig. 4 is a graph showing the results of example 3.

Detailed Description

Manganese ore, which is one of manganese-containing oxide substances, mainly contains oxides and sulfides of Ca, Si, Mg, Al, Fe, and P as components other than manganese. Here, the manganese oxide means that the manganese compound contains at least oxygen as an element and also contains Mn₇SiO₁₂Silicates represented by MnFe₂O₄Is a typical spinel compound.

Before the present invention, the inventors studied the mineral phase of manganese ore using XRD (X-ray diffraction ) and EPMA (Electron Probe Micro Analyzer). As a result, MnO containing Mn phase as a nonmagnetic material was confirmed₂With MnFe₂O₄A ferromagnetic spinel compound (hereinafter also referred to as "spinel phase"), typically represented by Mn₇SiO₁₂As a representative example, a weak magnet silicate (hereinafter also referred to as "silicate phase") exists. Here, the ferromagnetic body, the weak magnetic body, and the nonmagnetic body are classified according to the magnitude of magnetic permeability, and when magnetic separation is performed at a certain magnetic field strength, they are classified into the ferromagnetic body, the weak magnetic body, and the nonmagnetic body in order of easy magnetization. On the other hand, nCaO. P containing P phase and a nonmagnetic substance was confirmed₂O₅Compound phase (hereinafter also referred to as "nCaO. P")₂O₅Phase ") as the main component. It was also confirmed that the P-containing phase had a size of about 1 to 100 μm and existed in a phase different from the Mn-containing phase, although the phase varied depending on the mineral.

The inventors have intensively studied based on the above findings, focusing on the difference in magnetic properties between the Mn-containing phase and the P-containing phase, and as a result, have found a method capable of efficiently separating impurities from a manganese-containing oxide substance represented by manganese ore by pulverization and magnetic separation.

In the following detailed description, numerous specific details are set forth, such as embodiments of the present invention, in order to provide a thorough understanding of the present invention. It may be evident, however, that one or more embodiments may be practiced without these specific details. For the sake of simplicity, a known configuration and a known apparatus are schematically illustrated in the drawings.

< first embodiment >

A method for producing a manganese raw material according to a first embodiment of the present invention will be described with reference to fig. 1 and 2. In the first embodiment, the manganese-containing oxide substance used contains at least manganese, calcium, silicon, iron, and phosphorus, as represented by manganese ore. In addition, most of manganese, calcium, silicon, iron, and phosphorus are contained in the manganese oxide-containing substance in the form of an oxide. The manganese-containing oxide substance other than the above is not limited, and a manganese-containing oxide substance containing a manganese silicate compound is preferably used in order to efficiently recover the manganese raw material.

First, as shown in fig. 1, a pulverization step (S100) of pulverizing a manganese-containing oxide material as a raw material is performed. The method of pulverizing in the pulverizing step is not limited as long as the manganese oxide-containing substance can be pulverized into a predetermined size, and for reasons described later, a pulverizing method of pulverizing the manganese oxide-containing substance by applying pressure is preferable. As a method of pulverizing by applying pressure, there is a method using a ball mill, a rod mill, a roll mill, or the like. In addition, when the grinding is performed by a ball mill or a rod mill, the grinding time is preferably 1 hour or more, and the pressure applied when the grinding is performed by a roll mill is preferably 3MPa or more.

From the viewpoint of ease of handling in the magnetic separation step of the next step, the particle diameter of the manganese oxide-containing substance after pulverization (hereinafter also referred to as "pulverized manganese oxide-containing substance") may be a size exceeding 30 μm in terms of the center particle diameter, which is lower than about 500 μm and is not affected by aggregation of particles.

In the pulverizing step, nCaO. P as a nonmagnetic substance in the manganese oxide-containing substance is pulverized₂O₅Is in phase with MnFe₂O₄A spinel phase of a typical ferromagnetic material and a calcium ferrite phase of the ferromagnetic material are present unevenly in a form surrounded by them. The calcium ferrite phase is CaFe₂O₄Are representative phases. At least one of the spinel phase and the calcium ferrite phase, which are ferromagnetic substances contained in the pulverized manganese oxide-containing material, is also referred to as a ferromagnetic compound. That is, nCaO. P in which a manganese oxide-containing substance is pulverized into a ferromagnetic compound and a nonmagnetic substance₂O₅The phases and the manganese silicate phase of the weak magnet occupy most of the morphology.

Here, the present inventors have made an observation based on EPMA that nCaO. P, which is a high P-containing phase, is present during the pulverization₂O₅The phase is formed into a complex by complexing with a ferromagnetic compound, and forms a high-P-content particle that is easily magnetized as a particle. The composite is a particle comprising two or more phases separated as phases. That is, nCaO. P is added in the pulverizing step₂O₅The phase is surrounded by a ferromagnetic compound, and the highly P-containing particles having magnetism can be formed as particles. Further, the present inventors found through experiments that, in the case where manganese silicate is contained in the ore, the manganese silicate is in the form of particlesFormation of high P-containing particles having magnetic properties is promoted.

Next, a magnetic separation step of magnetically separating the pulverized manganese oxide-containing substance is performed to separate the pulverized manganese oxide-containing substance into a magnetized substance and a non-magnetized substance (S102). In the magnetic separation step, the magnetic force applied to the pulverized manganese-containing oxide material is set to a magnetic force at which the manganese silicate as a weak magnet is not magnetized. By setting the magnetic force in this way, a ferromagnetic compound and nCaO. P can be obtained₂O₅A phase-based magnetized substance and a non-magnetized substance mainly containing a manganese silicate phase, wherein nCaO. P₂O₅The phases are not uniformly present in a form surrounded by a ferromagnetic compound.

In the magnetic separation step, when the magnetic field to be applied is constant, the manganese silicate phase of the weak magnet is also involved in the magnetization of the ferromagnetic compound. Therefore, in the magnetic separation step, a magnetic separation device in which the magnetic field fluctuates with the passage of time is preferably used, and a magnetic separation device of a multipole magnetic field fluctuation system (for example, a magnetic separation device described in japanese patent application laid-open No. 2017-131869) is more preferably used.

After step S102, the non-magnetized material in the separated material separated in the magnetic separation step is recovered as a manganese raw material (S104). The non-magnetized substance recovered in step S104 mainly contains a manganese silicate phase, and nCaO. P unevenly distributed in a form surrounded by a ferromagnetic compound is removed from the pulverized manganese oxide-containing substance₂O₅Non-magnetized substance after phase separation. That is, the concentration of P can be reduced and the concentration of Mn can be increased relative to the manganese oxide-containing substance before recovery. Thus, a manganese raw material having a low P concentration and a high Mn concentration can be produced as compared with the manganese-containing oxide material before recovery.

On the other hand, after step S102, the magnetized material in the separated material separated in the magnetic separation step is recovered as an impurity (S106). The magnetized material recovered in step S106 mainly contains a ferromagnetic compound and nCaO. P unevenly distributed so as to be surrounded by the ferromagnetic compound₂O₅And (4) phase(s). The magnetic material has an increased P concentration and a decreased Mn concentration relative to the manganese oxide-containing material before recovery.

According to the method for producing a manganese raw material of the first embodiment, the crushed manganese-containing oxide substance is magnetically separated. At this time, nCaO. P containing P as an impurity is pulverized in the pulverizing step, as shown in FIG. 2₂O₅The compound is surrounded by at least one of a spinel phase and a calcium ferrite phase, which are ferromagnetic compounds, and magnetic high-P-containing particles can be formed as particles (fig. 2(a) and 2 (B)). In the magnetic separation step, the high-P-content particles are separated from the manganese silicate, whereby a high-purity manganese raw material having a low impurity P concentration and a high Mn concentration can be obtained (fig. 2C and 2D).

The manganese raw material recovered as a high-purity manganese raw material is then used for the smelting of manganese-containing steel. For example, by adding the recovered manganese raw material to molten iron before decarburization in a converter type refining furnace or the like, molten iron having a high manganese concentration can be produced. In the refining process using a converter type refining furnace or the like, when steel is tapped from the converter type refining furnace or the like, or when the steel is melted in a secondary refining facility such as a vacuum degasifier or a ladle refining apparatus, a molten iron having a high manganese concentration can be melted by adding the recovered manganese raw material to the molten iron. Since the P concentration of the recovered manganese raw material is lower than that of the manganese oxide-containing substance before pulverization, the recovered manganese raw material can be used in place of at least a part of other manganese raw materials having a low P concentration and a high price, and the melting cost can be greatly reduced.

This effect is particularly remarkable in the melting of high-manganese steel having a high Mn concentration such as high-strength steel. In addition, as long as the steel contains Mn, although the effect is different, the application is not limited to the high manganese steel, and the melting cost can be reduced. In particular, when smelting is performed by a secondary refining facility, dephosphorization is difficult to perform in subsequent steps including the smelting step, and therefore the effect of using the recovered manganese raw material is increased.

< second embodiment >

Next, a method for producing a manganese raw material according to a second embodiment of the present invention will be described with reference to fig. 3. The manganese-containing oxide substance used is the same as that of the first embodiment.

First, as shown in fig. 3, a first pulverization step (S200) of pulverizing the manganese oxide-containing substance is performed. In the first pulverization step, the manganese oxide-containing substance is pulverized in the same manner as in the pulverization step of the first embodiment.

Next, a classifying step (S202) of classifying the first pulverized manganese oxide-containing substance (the same as the "pulverized manganese oxide-containing substance" in the first embodiment) pulverized in the first pulverizing step into coarse particles and fine particles is performed. In the classification step, it is preferable to set the separation particle diameter to 150 μm or less, as observed from the particle diameter of the manganese silicate at the time of pulverization. The material having a particle size larger than the separation particle size is classified into coarse particles, and the material having a particle size of not more than the boundary value is classified into fine particles. In general, when the particle size is less than 30 μm, the particles aggregate with each other, and therefore, it is difficult to perform a process such as collection and transportation. Therefore, the separation particle diameter is preferably 30 μm or more. The classification method is not particularly limited as long as it is a method used in a general production process such as a cyclone separator and a sieve. For example, in the case of a classification method using a sieve, the mesh size may be set to 30 μm or more and 150 μm or less. In the classification method using a cyclone or the like, the separation particle diameter can be determined by changing the classification conditions represented by the flow rate conditions through trial and error. It is preferable to use a sieve whose classification size can be easily changed according to the change of the manganese oxide-containing substance of the raw material. In the classification step, a nonmagnetic nCaO. P having a small particle size and existing alone is separated from the first pulverized manganese-containing oxide substance after pulverization₂O₅Phase separation into fine particles. The fine particles classified in the classification step also include a spinel phase of a ferromagnetic material, a calcium ferrite phase of a ferromagnetic material, and a manganese silicate phase of a weak magnetic material, each of which has a small particle size and is present alone.

After step S202, a first magnetic separation step (S204) of magnetically separating the first pulverized manganese-containing oxide material separated as coarse particles in the classification step of step S202 is performed. In the first magnetic separation step, magnetic separation of the first pulverized manganese-containing oxide substance is performed by the same method as in the magnetic separation step in the first embodiment. In addition, in the first magnetic separatorIn the procedure, the magnetic force applied to the first pulverized manganese-containing oxide substance is set to a magnetic force (for example, 2000G or less) at which the manganese silicate as a weak magnet is not magnetized. In the first magnetic separation step, a ferromagnetic compound and nCaO. P unevenly distributed so as to be surrounded by the ferromagnetic compound are mainly separated₂O₅The phase separation into magnetides, mainly separating the manganese silicate as a weak magnet into non-magnetites.

After step S204, the manganese silicate having a large particle size separated as a non-magnetized material is recovered as a manganese raw material (S206).

After step S204, a second pulverization step (S208) of further pulverizing a first pulverized manganese oxide-containing substance mainly containing a ferromagnetic compound having a large particle size separated as a magnetic material and nCaO. P unevenly distributed so as to be surrounded by the ferromagnetic compound is performed₂O₅And (4) phase(s). In the second pulverization step, the first pulverized manganese oxide-containing substance is pulverized to obtain a second pulverized manganese oxide-containing substance having a smaller particle size. In this case, the first pulverized manganese-containing oxide substance is preferably pulverized to a particle size having a center particle size of 30 μm or less. In addition, the pulverization method is not particularly limited to the pulverization method in which pressure is applied. In the second grinding step, the first ground manganese oxide-containing substance is further ground to obtain nCaO. P surrounded by the ferromagnetic compound₂O₅The phases are divided into a spinel phase and a calcium ferrite phase as ferromagnetic compounds, and nCaO. P as a nonmagnetic substance₂O₅And (4) phase(s).

After step S208, a second magnetic separation step (S210) of magnetically separating the second pulverized manganese-containing oxide material is performed. In the second magnetic separation step, the magnetic separation of the second pulverized manganese-containing oxide material is performed by a method capable of suppressing aggregation, such as, for example, performing magnetic separation in a liquid. In the second magnetic separation step, the magnetic force applied to the second pulverized manganese-containing oxide substance may be the same as in the magnetic separation step of the first embodiment, and is preferably a magnetic force (for example, 5000G or more) in which the manganese silicate phase as a weak magnet is magnetized. In the second magnetic separation process, theThe spinel phase and the calcium ferrite phase which exist separately as strong magnetic compounds and the manganosilicate phase of weak magnets are separated into magnetized substances, and nCaO. P exists separately₂O₅The phases are separated into non-magnetised species.

After step S210, the spinel phase and the manganese silicate phase separated as the magnetized material are recovered as a manganese raw material (S212). A calcium ferrite phase is also included in the manganese source. However, when the content of P in the calcium ferrite phase is small and the manganese raw material is used in the refining of iron and steel, oxides of calcium and iron can be used as the steel-making raw material. Therefore, there is no problem in using the manganese raw material for iron and steel refining.

Further, after step S210, nCaO. P separated as a non-magnetized substance₂O₅The phase is recovered as an impurity (S214).

After step S202, a third magnetic separation step (S216) of magnetically separating the first pulverized manganese-containing oxide substance separated as fine particles in the classification step of step S202 is performed. In the third magnetic separation step, the magnetic separation of the first pulverized manganese-containing oxide material is performed by a method capable of suppressing aggregation, such as performing the magnetic separation step in a liquid. In the third magnetic separation step, the magnetic force applied to the first pulverized manganese-containing oxide substance may be any magnetic force that can magnetize the ferromagnetic spinel phase, and may be, for example, a magnetic force different from the magnetic force in the magnetic separation step in the first embodiment. In the primary magnetic separation step, a spinel phase and a calcium ferrite phase, which are ferromagnetic compounds and have small particle diameters and exist alone, and a manganese silicate, which is a weak magnet, are separated into magnetized substances, and nCaO. P, which has small particle diameters and exist alone, is separated₂O₅The phases are separated into non-magnetised species.

After step S216, the spinel phase and the manganese silicate phase separated as the magnetized material are recovered as a high-purity manganese raw material (S218). A calcium ferrite phase is also included in the manganese source. However, when the content of P in the calcium ferrite phase is small and the manganese raw material is used in the refining of iron steel, oxides of calcium and iron can be used as the raw material of refined steel. Therefore, there is no problem in using the manganese raw material for iron and steel refining.

After step S216, nCaO. P separated as a non-magnetized substance₂O₅The phase is recovered as an impurity (S220).

Thus, in the second embodiment, the manganese raw material recovered in steps S206, S212, and S218 is produced as a manganese raw material having a lower P concentration and a higher Mn concentration than the manganese-containing oxide substance before recovery.

In the second embodiment, in addition to the manufacturing method of the first embodiment, the classification step of step S202, the second pulverization step of step S208, the second magnetic separation step of step S210, and the third magnetic separation step of step S216 are performed. This also enables Mn contained in the spinel phase that could not be recovered in the first embodiment to be recovered, and therefore the recovery rate of Mn recovered from the manganese-containing oxide substance increases.

In the second embodiment, the manganese raw material recovered as the high-purity manganese raw material is used for the subsequent smelting of manganese-containing steel, as in the first embodiment. At this time, the high-purity manganese raw materials recovered in steps S206, S210, and S218 may be used together as one kind of manganese raw material, or the recovered raw materials may be used separately.

< modification example >

The present invention has been described above with reference to specific embodiments, but these descriptions are not intended to limit the present invention. The embodiments disclosed and other embodiments of the present invention including various modifications will be apparent to those skilled in the art from consideration of the specification of the present invention. Therefore, it is to be understood that the embodiments of the present invention recited in the claims include embodiments including these modifications recited in the present specification alone or in combination.

For example, the second embodiment is configured by adding the classification step, the second magnetic separation step, the second pulverization step, and the third magnetic separation step to the manufacturing method of the first embodiment, but the present invention is not limited to this example. For example, the manufacturing method of the first embodiment may be modified by adding the step described in any one of (a) to (D) below. In the following configurations (a) to (D), as described in the second embodiment, the embodiment including a step of recovering a manganese raw material (high-purity manganese raw material) after each step also includes the step.

(A) Classification procedure

(B) Classification procedure + second magnetic separation procedure

(C) Secondary crushing procedure and third magnetic separation procedure

(D) A classification procedure, a second crushing procedure and a third magnetic separation procedure

< effects of the embodiment >

(1) A method for producing a manganese raw material according to one embodiment of the present invention includes: a first pulverization step (the pulverization step of S100 or S200) wherein a first pulverized manganese-containing oxide substance containing at least manganese, calcium, silicon, iron and phosphorus is produced by using a manganese-containing oxide substance as a raw material and producing a composite by a compressive force generated by pulverizing the manganese-containing oxide substance, wherein the composite is formed by reacting at least one of a spinel phase and a calcium ferrite phase which are ferromagnetic bodies with nCaO.P₂O₅Compound phase composition; a first magnetic separation step (S102, magnetic separation step or S204) of magnetically separating the first pulverized manganese-containing oxide material produced in the first pulverization step into a magnetized material and a non-magnetized material; and a step (S104, S206) for recovering the non-magnetized material separated in the first magnetic separation step as a manganese raw material.

According to the constitution of the above (1), nCaO. P is formed by pulverizing while applying pressure in the pulverizing step₂O₅High P-containing particles in which a compound is surrounded by a ferromagnetic compound phase, the ferromagnetic compound phase being at least one of a spinel phase and a calcium ferrite phase. Then, the high-P-content particles are magnetically separated in the magnetic separation step, whereby a non-magnetized material having a low P concentration and a low Mn concentration is recovered as a manganese raw material. Since the P concentration of the manganese raw material is lower than that of the manganese-containing oxide material before pulverization, the use amount of expensive manganese raw material such as ferromanganese and metal manganese can be reduced by using the manganese raw material for smelting manganese-containing steel, and the smelting cost can be reduced.

Further, according to the configuration of the above (1), when the manganese-containing oxide substance is used, it is not necessary to subject the molten iron to be melted to dephosphorization. Therefore, manganese steel can be smelted without using harmful substances typified by BaO.

(2) In the configuration of the above (1), in the first pulverization step, the particle diameter of the first pulverized manganese-containing oxide substance is pulverized to 500 μm or less.

According to the constitution of the above (2), nCaO. P in the manganese oxide-containing substance can be promoted₂O₅Separation of the phase from the manganese silicate phase. Since the ratio of the particles containing P to the particles containing manganese silicate as the particles is increased, the magnetic separation in the first magnetic separation step is facilitated.

(3) In the above configuration (1) or (2), as the manganese-containing oxide substance, a substance containing a manganese silicate phase as a mineral phase is used.

According to the constitution of the above (3), formation of the high P-containing particles having magnetism as particles is promoted.

(4) In the configuration of the above (3), in the first magnetic separation step, the manganese silicate phase is separated into non-magnetized substances by separation using a magnetic force in which the manganese silicate phase is not magnetized.

According to the constitution of the above item (4), nCaO. P surrounded by the ferromagnetic compound phase and the manganese silicate phase can be more reliably performed₂O₅And (4) separating the phases. Therefore, the effect of separating impurities can be improved.

(5) In the configuration of any one of the above (1) to (4), in the first magnetic separation step, the magnetic field to be applied is a fluctuating magnetic field that changes with time.

According to the configuration of the above (5), the manganese silicate phase of the weak magnet, which is entangled in the spinel phase of the ferromagnetic compound during magnetic separation, can be separated from the ferromagnetic compound phase.

(6) In the above configuration (1) to (5), the first grinding step is followed by a classifying step (S202) of classifying the first ground manganese-containing oxide substance into coarse particles and fine particles at a separation particle size set to a range of 30 μm to 150 μm, and in the first magnetic separation step, the coarse particles classified in the classifying step are separated.

According to the above configuration (6), nCaO. P contained as fine particles in the pulverizing step can be treated₂O₅The phases are separated. Therefore, the P concentration of the manganese raw material recovered as a non-magnetized material in the magnetic separation step can be further reduced.

(7) In the configuration of the above (6), further comprising: a third magnetic separation step (S216) for magnetically separating the fine particles obtained by the classification step into a magnetized material and a non-magnetized material; and a step (S218) of recovering the magnetized material separated in the third magnetic separation step as a manganese raw material.

According to the configuration of the above (7), the spinel phase containing manganese contained in the fine particles can be recovered as a manganese raw material. Therefore, the recovery rate of the manganese raw material recovered from the manganese oxide-containing substance can be improved.

(8) In the configuration of any one of the above (1) to (7), further comprising: a second pulverization step (S208) for pulverizing the magnetic material separated in the first magnetic separation step to produce a second pulverized manganese-containing oxide substance; a second magnetic separation step (S210) for separating the magnetized material produced in the second pulverization step into a magnetized material and an unmagnetized material; and a step (S212) of recovering the magnetized material separated in the second magnetic separation step as a manganese raw material.

According to the constitution of the above item (8), nCaO. P surrounded by spinel phase as the magnetic material separated in the first magnetic separation step is subjected to magnetic separation₂O₅The phase is further refined to make it possible to phase the ferromagnetic compound with nCaO. P₂O₅The phases are separated. Further, the recovery rate of the manganese raw material recovered from the manganese oxide-containing substance can be improved by separating and recovering the phase of the ferromagnetic compound containing manganese by magnetization in the secondary magnetic separation step.

(9) The method for melting manganese steel according to one embodiment of the present invention includes: adding the manganese raw material recovered by the method for producing a manganese raw material according to any one of (1) to (8) above to molten iron or steel to adjust the manganese concentration of the molten iron or steel.

According to the configuration of the above (9), the same effects as those of the above (1) to (8) can be obtained.